001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    
019    package org.apache.hadoop.conf;
020    
021    import java.io.BufferedInputStream;
022    import java.io.DataInput;
023    import java.io.DataOutput;
024    import java.io.File;
025    import java.io.FileInputStream;
026    import java.io.IOException;
027    import java.io.InputStream;
028    import java.io.InputStreamReader;
029    import java.io.OutputStream;
030    import java.io.OutputStreamWriter;
031    import java.io.Reader;
032    import java.io.Writer;
033    import java.lang.ref.WeakReference;
034    import java.net.InetSocketAddress;
035    import java.net.URL;
036    import java.util.ArrayList;
037    import java.util.Arrays;
038    import java.util.Collection;
039    import java.util.Collections;
040    import java.util.Enumeration;
041    import java.util.HashMap;
042    import java.util.HashSet;
043    import java.util.Iterator;
044    import java.util.LinkedList;
045    import java.util.List;
046    import java.util.ListIterator;
047    import java.util.Map;
048    import java.util.Map.Entry;
049    import java.util.Properties;
050    import java.util.Set;
051    import java.util.StringTokenizer;
052    import java.util.WeakHashMap;
053    import java.util.concurrent.CopyOnWriteArrayList;
054    import java.util.regex.Matcher;
055    import java.util.regex.Pattern;
056    import java.util.regex.PatternSyntaxException;
057    import java.util.concurrent.TimeUnit;
058    import java.util.concurrent.atomic.AtomicBoolean;
059    import java.util.concurrent.atomic.AtomicReference;
060    
061    import javax.xml.parsers.DocumentBuilder;
062    import javax.xml.parsers.DocumentBuilderFactory;
063    import javax.xml.parsers.ParserConfigurationException;
064    import javax.xml.transform.Transformer;
065    import javax.xml.transform.TransformerException;
066    import javax.xml.transform.TransformerFactory;
067    import javax.xml.transform.dom.DOMSource;
068    import javax.xml.transform.stream.StreamResult;
069    
070    import org.apache.commons.collections.map.UnmodifiableMap;
071    import org.apache.commons.logging.Log;
072    import org.apache.commons.logging.LogFactory;
073    import org.apache.hadoop.classification.InterfaceAudience;
074    import org.apache.hadoop.classification.InterfaceStability;
075    import org.apache.hadoop.fs.FileSystem;
076    import org.apache.hadoop.fs.Path;
077    import org.apache.hadoop.fs.CommonConfigurationKeys;
078    import org.apache.hadoop.io.Writable;
079    import org.apache.hadoop.io.WritableUtils;
080    import org.apache.hadoop.net.NetUtils;
081    import org.apache.hadoop.util.ReflectionUtils;
082    import org.apache.hadoop.util.StringInterner;
083    import org.apache.hadoop.util.StringUtils;
084    import org.codehaus.jackson.JsonFactory;
085    import org.codehaus.jackson.JsonGenerator;
086    import org.w3c.dom.DOMException;
087    import org.w3c.dom.Document;
088    import org.w3c.dom.Element;
089    import org.w3c.dom.Node;
090    import org.w3c.dom.NodeList;
091    import org.w3c.dom.Text;
092    import org.xml.sax.SAXException;
093    
094    import com.google.common.base.Preconditions;
095    
096    /** 
097     * Provides access to configuration parameters.
098     *
099     * <h4 id="Resources">Resources</h4>
100     *
101     * <p>Configurations are specified by resources. A resource contains a set of
102     * name/value pairs as XML data. Each resource is named by either a 
103     * <code>String</code> or by a {@link Path}. If named by a <code>String</code>, 
104     * then the classpath is examined for a file with that name.  If named by a 
105     * <code>Path</code>, then the local filesystem is examined directly, without 
106     * referring to the classpath.
107     *
108     * <p>Unless explicitly turned off, Hadoop by default specifies two 
109     * resources, loaded in-order from the classpath: <ol>
110     * <li><tt><a href="{@docRoot}/../core-default.html">core-default.xml</a>
111     * </tt>: Read-only defaults for hadoop.</li>
112     * <li><tt>core-site.xml</tt>: Site-specific configuration for a given hadoop
113     * installation.</li>
114     * </ol>
115     * Applications may add additional resources, which are loaded
116     * subsequent to these resources in the order they are added.
117     * 
118     * <h4 id="FinalParams">Final Parameters</h4>
119     *
120     * <p>Configuration parameters may be declared <i>final</i>. 
121     * Once a resource declares a value final, no subsequently-loaded 
122     * resource can alter that value.  
123     * For example, one might define a final parameter with:
124     * <tt><pre>
125     *  &lt;property&gt;
126     *    &lt;name&gt;dfs.hosts.include&lt;/name&gt;
127     *    &lt;value&gt;/etc/hadoop/conf/hosts.include&lt;/value&gt;
128     *    <b>&lt;final&gt;true&lt;/final&gt;</b>
129     *  &lt;/property&gt;</pre></tt>
130     *
131     * Administrators typically define parameters as final in 
132     * <tt>core-site.xml</tt> for values that user applications may not alter.
133     *
134     * <h4 id="VariableExpansion">Variable Expansion</h4>
135     *
136     * <p>Value strings are first processed for <i>variable expansion</i>. The
137     * available properties are:<ol>
138     * <li>Other properties defined in this Configuration; and, if a name is
139     * undefined here,</li>
140     * <li>Properties in {@link System#getProperties()}.</li>
141     * </ol>
142     *
143     * <p>For example, if a configuration resource contains the following property
144     * definitions: 
145     * <tt><pre>
146     *  &lt;property&gt;
147     *    &lt;name&gt;basedir&lt;/name&gt;
148     *    &lt;value&gt;/user/${<i>user.name</i>}&lt;/value&gt;
149     *  &lt;/property&gt;
150     *  
151     *  &lt;property&gt;
152     *    &lt;name&gt;tempdir&lt;/name&gt;
153     *    &lt;value&gt;${<i>basedir</i>}/tmp&lt;/value&gt;
154     *  &lt;/property&gt;</pre></tt>
155     *
156     * When <tt>conf.get("tempdir")</tt> is called, then <tt>${<i>basedir</i>}</tt>
157     * will be resolved to another property in this Configuration, while
158     * <tt>${<i>user.name</i>}</tt> would then ordinarily be resolved to the value
159     * of the System property with that name.
160     * By default, warnings will be given to any deprecated configuration 
161     * parameters and these are suppressible by configuring
162     * <tt>log4j.logger.org.apache.hadoop.conf.Configuration.deprecation</tt> in
163     * log4j.properties file.
164     */
165    @InterfaceAudience.Public
166    @InterfaceStability.Stable
167    public class Configuration implements Iterable<Map.Entry<String,String>>,
168                                          Writable {
169      private static final Log LOG =
170        LogFactory.getLog(Configuration.class);
171    
172      private static final Log LOG_DEPRECATION =
173        LogFactory.getLog("org.apache.hadoop.conf.Configuration.deprecation");
174    
175      private boolean quietmode = true;
176      
177      private static class Resource {
178        private final Object resource;
179        private final String name;
180        
181        public Resource(Object resource) {
182          this(resource, resource.toString());
183        }
184        
185        public Resource(Object resource, String name) {
186          this.resource = resource;
187          this.name = name;
188        }
189        
190        public String getName(){
191          return name;
192        }
193        
194        public Object getResource() {
195          return resource;
196        }
197        
198        @Override
199        public String toString() {
200          return name;
201        }
202      }
203      
204      /**
205       * List of configuration resources.
206       */
207      private ArrayList<Resource> resources = new ArrayList<Resource>();
208      
209      /**
210       * The value reported as the setting resource when a key is set
211       * by code rather than a file resource by dumpConfiguration.
212       */
213      static final String UNKNOWN_RESOURCE = "Unknown";
214    
215    
216      /**
217       * List of configuration parameters marked <b>final</b>. 
218       */
219      private Set<String> finalParameters = new HashSet<String>();
220      
221      private boolean loadDefaults = true;
222      
223      /**
224       * Configuration objects
225       */
226      private static final WeakHashMap<Configuration,Object> REGISTRY = 
227        new WeakHashMap<Configuration,Object>();
228      
229      /**
230       * List of default Resources. Resources are loaded in the order of the list 
231       * entries
232       */
233      private static final CopyOnWriteArrayList<String> defaultResources =
234        new CopyOnWriteArrayList<String>();
235    
236      private static final Map<ClassLoader, Map<String, WeakReference<Class<?>>>>
237        CACHE_CLASSES = new WeakHashMap<ClassLoader, Map<String, WeakReference<Class<?>>>>();
238    
239      /**
240       * Sentinel value to store negative cache results in {@link #CACHE_CLASSES}.
241       */
242      private static final Class<?> NEGATIVE_CACHE_SENTINEL =
243        NegativeCacheSentinel.class;
244    
245      /**
246       * Stores the mapping of key to the resource which modifies or loads 
247       * the key most recently
248       */
249      private HashMap<String, String[]> updatingResource;
250     
251      /**
252       * Class to keep the information about the keys which replace the deprecated
253       * ones.
254       * 
255       * This class stores the new keys which replace the deprecated keys and also
256       * gives a provision to have a custom message for each of the deprecated key
257       * that is being replaced. It also provides method to get the appropriate
258       * warning message which can be logged whenever the deprecated key is used.
259       */
260      private static class DeprecatedKeyInfo {
261        private final String[] newKeys;
262        private final String customMessage;
263        private final AtomicBoolean accessed = new AtomicBoolean(false);
264    
265        DeprecatedKeyInfo(String[] newKeys, String customMessage) {
266          this.newKeys = newKeys;
267          this.customMessage = customMessage;
268        }
269    
270        /**
271         * Method to provide the warning message. It gives the custom message if
272         * non-null, and default message otherwise.
273         * @param key the associated deprecated key.
274         * @return message that is to be logged when a deprecated key is used.
275         */
276        private final String getWarningMessage(String key) {
277          String warningMessage;
278          if(customMessage == null) {
279            StringBuilder message = new StringBuilder(key);
280            String deprecatedKeySuffix = " is deprecated. Instead, use ";
281            message.append(deprecatedKeySuffix);
282            for (int i = 0; i < newKeys.length; i++) {
283              message.append(newKeys[i]);
284              if(i != newKeys.length-1) {
285                message.append(", ");
286              }
287            }
288            warningMessage = message.toString();
289          }
290          else {
291            warningMessage = customMessage;
292          }
293          return warningMessage;
294        }
295    
296        boolean getAndSetAccessed() {
297          return accessed.getAndSet(true);
298        }
299    
300        public void clearAccessed() {
301          accessed.set(false);
302        }
303      }
304      
305      /**
306       * A pending addition to the global set of deprecated keys.
307       */
308      public static class DeprecationDelta {
309        private final String key;
310        private final String[] newKeys;
311        private final String customMessage;
312    
313        DeprecationDelta(String key, String[] newKeys, String customMessage) {
314          Preconditions.checkNotNull(key);
315          Preconditions.checkNotNull(newKeys);
316          Preconditions.checkArgument(newKeys.length > 0);
317          this.key = key;
318          this.newKeys = newKeys;
319          this.customMessage = customMessage;
320        }
321    
322        public DeprecationDelta(String key, String newKey, String customMessage) {
323          this(key, new String[] { newKey }, customMessage);
324        }
325    
326        public DeprecationDelta(String key, String newKey) {
327          this(key, new String[] { newKey }, null);
328        }
329    
330        public String getKey() {
331          return key;
332        }
333    
334        public String[] getNewKeys() {
335          return newKeys;
336        }
337    
338        public String getCustomMessage() {
339          return customMessage;
340        }
341      }
342    
343      /**
344       * The set of all keys which are deprecated.
345       *
346       * DeprecationContext objects are immutable.
347       */
348      private static class DeprecationContext {
349        /**
350         * Stores the deprecated keys, the new keys which replace the deprecated keys
351         * and custom message(if any provided).
352         */
353        private final Map<String, DeprecatedKeyInfo> deprecatedKeyMap;
354    
355        /**
356         * Stores a mapping from superseding keys to the keys which they deprecate.
357         */
358        private final Map<String, String> reverseDeprecatedKeyMap;
359    
360        /**
361         * Create a new DeprecationContext by copying a previous DeprecationContext
362         * and adding some deltas.
363         *
364         * @param other   The previous deprecation context to copy, or null to start
365         *                from nothing.
366         * @param deltas  The deltas to apply.
367         */
368        @SuppressWarnings("unchecked")
369        DeprecationContext(DeprecationContext other, DeprecationDelta[] deltas) {
370          HashMap<String, DeprecatedKeyInfo> newDeprecatedKeyMap = 
371            new HashMap<String, DeprecatedKeyInfo>();
372          HashMap<String, String> newReverseDeprecatedKeyMap =
373            new HashMap<String, String>();
374          if (other != null) {
375            for (Entry<String, DeprecatedKeyInfo> entry :
376                other.deprecatedKeyMap.entrySet()) {
377              newDeprecatedKeyMap.put(entry.getKey(), entry.getValue());
378            }
379            for (Entry<String, String> entry :
380                other.reverseDeprecatedKeyMap.entrySet()) {
381              newReverseDeprecatedKeyMap.put(entry.getKey(), entry.getValue());
382            }
383          }
384          for (DeprecationDelta delta : deltas) {
385            if (!newDeprecatedKeyMap.containsKey(delta.getKey())) {
386              DeprecatedKeyInfo newKeyInfo =
387                new DeprecatedKeyInfo(delta.getNewKeys(), delta.getCustomMessage());
388              newDeprecatedKeyMap.put(delta.key, newKeyInfo);
389              for (String newKey : delta.getNewKeys()) {
390                newReverseDeprecatedKeyMap.put(newKey, delta.key);
391              }
392            }
393          }
394          this.deprecatedKeyMap =
395            UnmodifiableMap.decorate(newDeprecatedKeyMap);
396          this.reverseDeprecatedKeyMap =
397            UnmodifiableMap.decorate(newReverseDeprecatedKeyMap);
398        }
399    
400        Map<String, DeprecatedKeyInfo> getDeprecatedKeyMap() {
401          return deprecatedKeyMap;
402        }
403    
404        Map<String, String> getReverseDeprecatedKeyMap() {
405          return reverseDeprecatedKeyMap;
406        }
407      }
408      
409      private static DeprecationDelta[] defaultDeprecations = 
410        new DeprecationDelta[] {
411          new DeprecationDelta("topology.script.file.name", 
412            CommonConfigurationKeys.NET_TOPOLOGY_SCRIPT_FILE_NAME_KEY),
413          new DeprecationDelta("topology.script.number.args", 
414            CommonConfigurationKeys.NET_TOPOLOGY_SCRIPT_NUMBER_ARGS_KEY),
415          new DeprecationDelta("hadoop.configured.node.mapping", 
416            CommonConfigurationKeys.NET_TOPOLOGY_CONFIGURED_NODE_MAPPING_KEY),
417          new DeprecationDelta("topology.node.switch.mapping.impl", 
418            CommonConfigurationKeys.NET_TOPOLOGY_NODE_SWITCH_MAPPING_IMPL_KEY),
419          new DeprecationDelta("dfs.df.interval", 
420            CommonConfigurationKeys.FS_DF_INTERVAL_KEY),
421          new DeprecationDelta("hadoop.native.lib", 
422            CommonConfigurationKeys.IO_NATIVE_LIB_AVAILABLE_KEY),
423          new DeprecationDelta("fs.default.name", 
424            CommonConfigurationKeys.FS_DEFAULT_NAME_KEY),
425          new DeprecationDelta("dfs.umaskmode",
426            CommonConfigurationKeys.FS_PERMISSIONS_UMASK_KEY)
427        };
428    
429      /**
430       * The global DeprecationContext.
431       */
432      private static AtomicReference<DeprecationContext> deprecationContext =
433          new AtomicReference<DeprecationContext>(
434              new DeprecationContext(null, defaultDeprecations));
435    
436      /**
437       * Adds a set of deprecated keys to the global deprecations.
438       *
439       * This method is lockless.  It works by means of creating a new
440       * DeprecationContext based on the old one, and then atomically swapping in
441       * the new context.  If someone else updated the context in between us reading
442       * the old context and swapping in the new one, we try again until we win the
443       * race.
444       *
445       * @param deltas   The deprecations to add.
446       */
447      public static void addDeprecations(DeprecationDelta[] deltas) {
448        DeprecationContext prev, next;
449        do {
450          prev = deprecationContext.get();
451          next = new DeprecationContext(prev, deltas);
452        } while (!deprecationContext.compareAndSet(prev, next));
453      }
454    
455      /**
456       * Adds the deprecated key to the global deprecation map.
457       * It does not override any existing entries in the deprecation map.
458       * This is to be used only by the developers in order to add deprecation of
459       * keys, and attempts to call this method after loading resources once,
460       * would lead to <tt>UnsupportedOperationException</tt>
461       * 
462       * If a key is deprecated in favor of multiple keys, they are all treated as 
463       * aliases of each other, and setting any one of them resets all the others 
464       * to the new value.
465       *
466       * If you have multiple deprecation entries to add, it is more efficient to
467       * use #addDeprecations(DeprecationDelta[] deltas) instead.
468       * 
469       * @param key
470       * @param newKeys
471       * @param customMessage
472       * @deprecated use {@link #addDeprecation(String key, String newKey,
473          String customMessage)} instead
474       */
475      @Deprecated
476      public static void addDeprecation(String key, String[] newKeys,
477          String customMessage) {
478        addDeprecations(new DeprecationDelta[] {
479          new DeprecationDelta(key, newKeys, customMessage)
480        });
481      }
482    
483      /**
484       * Adds the deprecated key to the global deprecation map.
485       * It does not override any existing entries in the deprecation map.
486       * This is to be used only by the developers in order to add deprecation of
487       * keys, and attempts to call this method after loading resources once,
488       * would lead to <tt>UnsupportedOperationException</tt>
489       * 
490       * If you have multiple deprecation entries to add, it is more efficient to
491       * use #addDeprecations(DeprecationDelta[] deltas) instead.
492       *
493       * @param key
494       * @param newKey
495       * @param customMessage
496       */
497      public static void addDeprecation(String key, String newKey,
498                  String customMessage) {
499              addDeprecation(key, new String[] {newKey}, customMessage);
500      }
501    
502      /**
503       * Adds the deprecated key to the global deprecation map when no custom
504       * message is provided.
505       * It does not override any existing entries in the deprecation map.
506       * This is to be used only by the developers in order to add deprecation of
507       * keys, and attempts to call this method after loading resources once,
508       * would lead to <tt>UnsupportedOperationException</tt>
509       * 
510       * If a key is deprecated in favor of multiple keys, they are all treated as 
511       * aliases of each other, and setting any one of them resets all the others 
512       * to the new value.
513       * 
514       * If you have multiple deprecation entries to add, it is more efficient to
515       * use #addDeprecations(DeprecationDelta[] deltas) instead.
516       *
517       * @param key Key that is to be deprecated
518       * @param newKeys list of keys that take up the values of deprecated key
519       * @deprecated use {@link #addDeprecation(String key, String newKey)} instead
520       */
521      @Deprecated
522      public static void addDeprecation(String key, String[] newKeys) {
523        addDeprecation(key, newKeys, null);
524      }
525      
526      /**
527       * Adds the deprecated key to the global deprecation map when no custom
528       * message is provided.
529       * It does not override any existing entries in the deprecation map.
530       * This is to be used only by the developers in order to add deprecation of
531       * keys, and attempts to call this method after loading resources once,
532       * would lead to <tt>UnsupportedOperationException</tt>
533       * 
534       * If you have multiple deprecation entries to add, it is more efficient to
535       * use #addDeprecations(DeprecationDelta[] deltas) instead.
536       *
537       * @param key Key that is to be deprecated
538       * @param newKey key that takes up the value of deprecated key
539       */
540      public static void addDeprecation(String key, String newKey) {
541        addDeprecation(key, new String[] {newKey}, null);
542      }
543      
544      /**
545       * checks whether the given <code>key</code> is deprecated.
546       * 
547       * @param key the parameter which is to be checked for deprecation
548       * @return <code>true</code> if the key is deprecated and 
549       *         <code>false</code> otherwise.
550       */
551      public static boolean isDeprecated(String key) {
552        return deprecationContext.get().getDeprecatedKeyMap().containsKey(key);
553      }
554    
555      /**
556       * Checks for the presence of the property <code>name</code> in the
557       * deprecation map. Returns the first of the list of new keys if present
558       * in the deprecation map or the <code>name</code> itself. If the property
559       * is not presently set but the property map contains an entry for the
560       * deprecated key, the value of the deprecated key is set as the value for
561       * the provided property name.
562       *
563       * @param name the property name
564       * @return the first property in the list of properties mapping
565       *         the <code>name</code> or the <code>name</code> itself.
566       */
567      private String[] handleDeprecation(DeprecationContext deprecations,
568          String name) {
569        ArrayList<String > names = new ArrayList<String>();
570            if (isDeprecated(name)) {
571          DeprecatedKeyInfo keyInfo = deprecations.getDeprecatedKeyMap().get(name);
572          warnOnceIfDeprecated(deprecations, name);
573          for (String newKey : keyInfo.newKeys) {
574            if(newKey != null) {
575              names.add(newKey);
576            }
577          }
578        }
579        if(names.size() == 0) {
580            names.add(name);
581        }
582        for(String n : names) {
583              String deprecatedKey = deprecations.getReverseDeprecatedKeyMap().get(n);
584              if (deprecatedKey != null && !getOverlay().containsKey(n) &&
585                  getOverlay().containsKey(deprecatedKey)) {
586                getProps().setProperty(n, getOverlay().getProperty(deprecatedKey));
587                getOverlay().setProperty(n, getOverlay().getProperty(deprecatedKey));
588              }
589        }
590        return names.toArray(new String[names.size()]);
591      }
592     
593      private void handleDeprecation() {
594        LOG.debug("Handling deprecation for all properties in config...");
595        DeprecationContext deprecations = deprecationContext.get();
596        Set<Object> keys = new HashSet<Object>();
597        keys.addAll(getProps().keySet());
598        for (Object item: keys) {
599          LOG.debug("Handling deprecation for " + (String)item);
600          handleDeprecation(deprecations, (String)item);
601        }
602      }
603     
604      static{
605        //print deprecation warning if hadoop-site.xml is found in classpath
606        ClassLoader cL = Thread.currentThread().getContextClassLoader();
607        if (cL == null) {
608          cL = Configuration.class.getClassLoader();
609        }
610        if(cL.getResource("hadoop-site.xml")!=null) {
611          LOG.warn("DEPRECATED: hadoop-site.xml found in the classpath. " +
612              "Usage of hadoop-site.xml is deprecated. Instead use core-site.xml, "
613              + "mapred-site.xml and hdfs-site.xml to override properties of " +
614              "core-default.xml, mapred-default.xml and hdfs-default.xml " +
615              "respectively");
616        }
617        addDefaultResource("core-default.xml");
618        addDefaultResource("org.apache.hadoop.conf.CoreDefaultProperties");
619        addDefaultResource("core-site.xml");
620      }
621      
622      private Properties properties;
623      private Properties overlay;
624      private ClassLoader classLoader;
625      {
626        classLoader = Thread.currentThread().getContextClassLoader();
627        if (classLoader == null) {
628          classLoader = Configuration.class.getClassLoader();
629        }
630      }
631      
632      /** A new configuration. */
633      public Configuration() {
634        this(true);
635      }
636    
637      /** A new configuration where the behavior of reading from the default 
638       * resources can be turned off.
639       * 
640       * If the parameter {@code loadDefaults} is false, the new instance
641       * will not load resources from the default files. 
642       * @param loadDefaults specifies whether to load from the default files
643       */
644      public Configuration(boolean loadDefaults) {
645        this.loadDefaults = loadDefaults;
646        updatingResource = new HashMap<String, String[]>();
647        synchronized(Configuration.class) {
648          REGISTRY.put(this, null);
649        }
650      }
651      
652      /** 
653       * A new configuration with the same settings cloned from another.
654       * 
655       * @param other the configuration from which to clone settings.
656       */
657      @SuppressWarnings("unchecked")
658      public Configuration(Configuration other) {
659       this.resources = (ArrayList<Resource>) other.resources.clone();
660       synchronized(other) {
661         if (other.properties != null) {
662           this.properties = (Properties)other.properties.clone();
663         }
664    
665         if (other.overlay!=null) {
666           this.overlay = (Properties)other.overlay.clone();
667         }
668    
669         this.updatingResource = new HashMap<String, String[]>(other.updatingResource);
670       }
671       
672        this.finalParameters = new HashSet<String>(other.finalParameters);
673        synchronized(Configuration.class) {
674          REGISTRY.put(this, null);
675        }
676        this.classLoader = other.classLoader;
677        this.loadDefaults = other.loadDefaults;
678        setQuietMode(other.getQuietMode());
679      }
680      
681      /**
682       * Add a default resource. Resources are loaded in the order of the resources 
683       * added.
684       * @param name file name. File should be present in the classpath.
685       */
686      public static synchronized void addDefaultResource(String name) {
687        if(!defaultResources.contains(name)) {
688          defaultResources.add(name);
689          for(Configuration conf : REGISTRY.keySet()) {
690            if(conf.loadDefaults) {
691              conf.reloadConfiguration();
692            }
693          }
694        }
695      }
696    
697      /**
698       * Add a configuration resource. 
699       * 
700       * The properties of this resource will override properties of previously 
701       * added resources, unless they were marked <a href="#Final">final</a>. 
702       * 
703       * @param name resource to be added, the classpath is examined for a file 
704       *             with that name.
705       */
706      public void addResource(String name) {
707        addResourceObject(new Resource(name));
708      }
709    
710      /**
711       * Add a configuration resource. 
712       * 
713       * The properties of this resource will override properties of previously 
714       * added resources, unless they were marked <a href="#Final">final</a>. 
715       * 
716       * @param url url of the resource to be added, the local filesystem is 
717       *            examined directly to find the resource, without referring to 
718       *            the classpath.
719       */
720      public void addResource(URL url) {
721        addResourceObject(new Resource(url));
722      }
723    
724      /**
725       * Add a configuration resource. 
726       * 
727       * The properties of this resource will override properties of previously 
728       * added resources, unless they were marked <a href="#Final">final</a>. 
729       * 
730       * @param file file-path of resource to be added, the local filesystem is
731       *             examined directly to find the resource, without referring to 
732       *             the classpath.
733       */
734      public void addResource(Path file) {
735        addResourceObject(new Resource(file));
736      }
737    
738      /**
739       * Add a configuration resource. 
740       * 
741       * The properties of this resource will override properties of previously 
742       * added resources, unless they were marked <a href="#Final">final</a>. 
743       * 
744       * WARNING: The contents of the InputStream will be cached, by this method. 
745       * So use this sparingly because it does increase the memory consumption.
746       * 
747       * @param in InputStream to deserialize the object from. In will be read from
748       * when a get or set is called next.  After it is read the stream will be
749       * closed. 
750       */
751      public void addResource(InputStream in) {
752        addResourceObject(new Resource(in));
753      }
754    
755      /**
756       * Add a configuration resource. 
757       * 
758       * The properties of this resource will override properties of previously 
759       * added resources, unless they were marked <a href="#Final">final</a>. 
760       * 
761       * @param in InputStream to deserialize the object from.
762       * @param name the name of the resource because InputStream.toString is not
763       * very descriptive some times.  
764       */
765      public void addResource(InputStream in, String name) {
766        addResourceObject(new Resource(in, name));
767      }
768      
769      
770      /**
771       * Reload configuration from previously added resources.
772       *
773       * This method will clear all the configuration read from the added 
774       * resources, and final parameters. This will make the resources to 
775       * be read again before accessing the values. Values that are added
776       * via set methods will overlay values read from the resources.
777       */
778      public synchronized void reloadConfiguration() {
779        properties = null;                            // trigger reload
780        finalParameters.clear();                      // clear site-limits
781      }
782      
783      private synchronized void addResourceObject(Resource resource) {
784        resources.add(resource);                      // add to resources
785        reloadConfiguration();
786      }
787      
788      private static Pattern varPat = Pattern.compile("\\$\\{[^\\}\\$\u0020]+\\}");
789      private static int MAX_SUBST = 20;
790    
791      private String substituteVars(String expr) {
792        if (expr == null) {
793          return null;
794        }
795        Matcher match = varPat.matcher("");
796        String eval = expr;
797        for(int s=0; s<MAX_SUBST; s++) {
798          match.reset(eval);
799          if (!match.find()) {
800            return eval;
801          }
802          String var = match.group();
803          var = var.substring(2, var.length()-1); // remove ${ .. }
804          String val = null;
805          try {
806            val = System.getProperty(var);
807          } catch(SecurityException se) {
808            LOG.warn("Unexpected SecurityException in Configuration", se);
809          }
810          if (val == null) {
811            val = getRaw(var);
812          }
813          if (val == null) {
814            return eval; // return literal ${var}: var is unbound
815          }
816          // substitute
817          eval = eval.substring(0, match.start())+val+eval.substring(match.end());
818        }
819        throw new IllegalStateException("Variable substitution depth too large: " 
820                                        + MAX_SUBST + " " + expr);
821      }
822      
823      /**
824       * Get the value of the <code>name</code> property, <code>null</code> if
825       * no such property exists. If the key is deprecated, it returns the value of
826       * the first key which replaces the deprecated key and is not null
827       * 
828       * Values are processed for <a href="#VariableExpansion">variable expansion</a> 
829       * before being returned. 
830       * 
831       * @param name the property name.
832       * @return the value of the <code>name</code> or its replacing property, 
833       *         or null if no such property exists.
834       */
835      public String get(String name) {
836        String[] names = handleDeprecation(deprecationContext.get(), name);
837        String result = null;
838        for(String n : names) {
839          result = substituteVars(getProps().getProperty(n));
840        }
841        return result;
842      }
843      
844      /**
845       * Get the value of the <code>name</code> property as a trimmed <code>String</code>, 
846       * <code>null</code> if no such property exists. 
847       * If the key is deprecated, it returns the value of
848       * the first key which replaces the deprecated key and is not null
849       * 
850       * Values are processed for <a href="#VariableExpansion">variable expansion</a> 
851       * before being returned. 
852       * 
853       * @param name the property name.
854       * @return the value of the <code>name</code> or its replacing property, 
855       *         or null if no such property exists.
856       */
857      public String getTrimmed(String name) {
858        String value = get(name);
859        
860        if (null == value) {
861          return null;
862        } else {
863          return value.trim();
864        }
865      }
866      
867      /**
868       * Get the value of the <code>name</code> property as a trimmed <code>String</code>, 
869       * <code>defaultValue</code> if no such property exists. 
870       * See @{Configuration#getTrimmed} for more details.
871       * 
872       * @param name          the property name.
873       * @param defaultValue  the property default value.
874       * @return              the value of the <code>name</code> or defaultValue
875       *                      if it is not set.
876       */
877      public String getTrimmed(String name, String defaultValue) {
878        String ret = getTrimmed(name);
879        return ret == null ? defaultValue : ret;
880      }
881    
882      /**
883       * Get the value of the <code>name</code> property, without doing
884       * <a href="#VariableExpansion">variable expansion</a>.If the key is 
885       * deprecated, it returns the value of the first key which replaces 
886       * the deprecated key and is not null.
887       * 
888       * @param name the property name.
889       * @return the value of the <code>name</code> property or 
890       *         its replacing property and null if no such property exists.
891       */
892      public String getRaw(String name) {
893        String[] names = handleDeprecation(deprecationContext.get(), name);
894        String result = null;
895        for(String n : names) {
896          result = getProps().getProperty(n);
897        }
898        return result;
899      }
900    
901      /**
902       * Returns alternative names (non-deprecated keys or previously-set deprecated keys)
903       * for a given non-deprecated key.
904       * If the given key is deprecated, return null.
905       *
906       * @param name property name.
907       * @return alternative names.
908       */
909      private String[] getAlternativeNames(String name) {
910        String altNames[] = null;
911        DeprecatedKeyInfo keyInfo = null;
912        DeprecationContext cur = deprecationContext.get();
913        String depKey = cur.getReverseDeprecatedKeyMap().get(name);
914        if(depKey != null) {
915          keyInfo = cur.getDeprecatedKeyMap().get(depKey);
916          if(keyInfo.newKeys.length > 0) {
917            if(getProps().containsKey(depKey)) {
918              //if deprecated key is previously set explicitly
919              List<String> list = new ArrayList<String>();
920              list.addAll(Arrays.asList(keyInfo.newKeys));
921              list.add(depKey);
922              altNames = list.toArray(new String[list.size()]);
923            }
924            else {
925              altNames = keyInfo.newKeys;
926            }
927          }
928        }
929        return altNames;
930      }
931    
932      /** 
933       * Set the <code>value</code> of the <code>name</code> property. If 
934       * <code>name</code> is deprecated or there is a deprecated name associated to it,
935       * it sets the value to both names.
936       * 
937       * @param name property name.
938       * @param value property value.
939       */
940      public void set(String name, String value) {
941        set(name, value, null);
942      }
943      
944      /** 
945       * Set the <code>value</code> of the <code>name</code> property. If 
946       * <code>name</code> is deprecated, it also sets the <code>value</code> to
947       * the keys that replace the deprecated key.
948       *
949       * @param name property name.
950       * @param value property value.
951       * @param source the place that this configuration value came from 
952       * (For debugging).
953       * @throws IllegalArgumentException when the value or name is null.
954       */
955      public void set(String name, String value, String source) {
956        Preconditions.checkArgument(
957            name != null,
958            "Property name must not be null");
959        Preconditions.checkArgument(
960            value != null,
961            "Property value must not be null");
962        DeprecationContext deprecations = deprecationContext.get();
963        if (deprecations.getDeprecatedKeyMap().isEmpty()) {
964          getProps();
965        }
966        getOverlay().setProperty(name, value);
967        getProps().setProperty(name, value);
968        String newSource = (source == null ? "programatically" : source);
969    
970        if (!isDeprecated(name)) {
971          updatingResource.put(name, new String[] {newSource});
972          String[] altNames = getAlternativeNames(name);
973          if(altNames != null) {
974            for(String n: altNames) {
975              if(!n.equals(name)) {
976                getOverlay().setProperty(n, value);
977                getProps().setProperty(n, value);
978                updatingResource.put(n, new String[] {newSource});
979              }
980            }
981          }
982        }
983        else {
984          String[] names = handleDeprecation(deprecationContext.get(), name);
985          String altSource = "because " + name + " is deprecated";
986          for(String n : names) {
987            getOverlay().setProperty(n, value);
988            getProps().setProperty(n, value);
989            updatingResource.put(n, new String[] {altSource});
990          }
991        }
992      }
993    
994      private void warnOnceIfDeprecated(DeprecationContext deprecations, String name) {
995        DeprecatedKeyInfo keyInfo = deprecations.getDeprecatedKeyMap().get(name);
996        if (keyInfo != null && !keyInfo.getAndSetAccessed()) {
997          LOG_DEPRECATION.info(keyInfo.getWarningMessage(name));
998        }
999      }
1000    
1001      /**
1002       * Unset a previously set property.
1003       */
1004      public synchronized void unset(String name) {
1005        String[] names = null;
1006        if (!isDeprecated(name)) {
1007          names = getAlternativeNames(name);
1008          if(names == null) {
1009              names = new String[]{name};
1010          }
1011        }
1012        else {
1013          names = handleDeprecation(deprecationContext.get(), name);
1014        }
1015    
1016        for(String n: names) {
1017          getOverlay().remove(n);
1018          getProps().remove(n);
1019        }
1020      }
1021    
1022      /**
1023       * Sets a property if it is currently unset.
1024       * @param name the property name
1025       * @param value the new value
1026       */
1027      public synchronized void setIfUnset(String name, String value) {
1028        if (get(name) == null) {
1029          set(name, value);
1030        }
1031      }
1032      
1033      private synchronized Properties getOverlay() {
1034        if (overlay==null){
1035          overlay=new Properties();
1036        }
1037        return overlay;
1038      }
1039    
1040      /** 
1041       * Get the value of the <code>name</code>. If the key is deprecated,
1042       * it returns the value of the first key which replaces the deprecated key
1043       * and is not null.
1044       * If no such property exists,
1045       * then <code>defaultValue</code> is returned.
1046       * 
1047       * @param name property name.
1048       * @param defaultValue default value.
1049       * @return property value, or <code>defaultValue</code> if the property 
1050       *         doesn't exist.                    
1051       */
1052      public String get(String name, String defaultValue) {
1053        String[] names = handleDeprecation(deprecationContext.get(), name);
1054        String result = null;
1055        for(String n : names) {
1056          result = substituteVars(getProps().getProperty(n, defaultValue));
1057        }
1058        return result;
1059      }
1060    
1061      /** 
1062       * Get the value of the <code>name</code> property as an <code>int</code>.
1063       *   
1064       * If no such property exists, the provided default value is returned,
1065       * or if the specified value is not a valid <code>int</code>,
1066       * then an error is thrown.
1067       * 
1068       * @param name property name.
1069       * @param defaultValue default value.
1070       * @throws NumberFormatException when the value is invalid
1071       * @return property value as an <code>int</code>, 
1072       *         or <code>defaultValue</code>. 
1073       */
1074      public int getInt(String name, int defaultValue) {
1075        String valueString = getTrimmed(name);
1076        if (valueString == null)
1077          return defaultValue;
1078        String hexString = getHexDigits(valueString);
1079        if (hexString != null) {
1080          return Integer.parseInt(hexString, 16);
1081        }
1082        return Integer.parseInt(valueString);
1083      }
1084      
1085      /**
1086       * Get the value of the <code>name</code> property as a set of comma-delimited
1087       * <code>int</code> values.
1088       * 
1089       * If no such property exists, an empty array is returned.
1090       * 
1091       * @param name property name
1092       * @return property value interpreted as an array of comma-delimited
1093       *         <code>int</code> values
1094       */
1095      public int[] getInts(String name) {
1096        String[] strings = getTrimmedStrings(name);
1097        int[] ints = new int[strings.length];
1098        for (int i = 0; i < strings.length; i++) {
1099          ints[i] = Integer.parseInt(strings[i]);
1100        }
1101        return ints;
1102      }
1103    
1104      /** 
1105       * Set the value of the <code>name</code> property to an <code>int</code>.
1106       * 
1107       * @param name property name.
1108       * @param value <code>int</code> value of the property.
1109       */
1110      public void setInt(String name, int value) {
1111        set(name, Integer.toString(value));
1112      }
1113    
1114    
1115      /** 
1116       * Get the value of the <code>name</code> property as a <code>long</code>.  
1117       * If no such property exists, the provided default value is returned,
1118       * or if the specified value is not a valid <code>long</code>,
1119       * then an error is thrown.
1120       * 
1121       * @param name property name.
1122       * @param defaultValue default value.
1123       * @throws NumberFormatException when the value is invalid
1124       * @return property value as a <code>long</code>, 
1125       *         or <code>defaultValue</code>. 
1126       */
1127      public long getLong(String name, long defaultValue) {
1128        String valueString = getTrimmed(name);
1129        if (valueString == null)
1130          return defaultValue;
1131        String hexString = getHexDigits(valueString);
1132        if (hexString != null) {
1133          return Long.parseLong(hexString, 16);
1134        }
1135        return Long.parseLong(valueString);
1136      }
1137    
1138      /**
1139       * Get the value of the <code>name</code> property as a <code>long</code> or
1140       * human readable format. If no such property exists, the provided default
1141       * value is returned, or if the specified value is not a valid
1142       * <code>long</code> or human readable format, then an error is thrown. You
1143       * can use the following suffix (case insensitive): k(kilo), m(mega), g(giga),
1144       * t(tera), p(peta), e(exa)
1145       *
1146       * @param name property name.
1147       * @param defaultValue default value.
1148       * @throws NumberFormatException when the value is invalid
1149       * @return property value as a <code>long</code>,
1150       *         or <code>defaultValue</code>.
1151       */
1152      public long getLongBytes(String name, long defaultValue) {
1153        String valueString = getTrimmed(name);
1154        if (valueString == null)
1155          return defaultValue;
1156        return StringUtils.TraditionalBinaryPrefix.string2long(valueString);
1157      }
1158    
1159      private String getHexDigits(String value) {
1160        boolean negative = false;
1161        String str = value;
1162        String hexString = null;
1163        if (value.startsWith("-")) {
1164          negative = true;
1165          str = value.substring(1);
1166        }
1167        if (str.startsWith("0x") || str.startsWith("0X")) {
1168          hexString = str.substring(2);
1169          if (negative) {
1170            hexString = "-" + hexString;
1171          }
1172          return hexString;
1173        }
1174        return null;
1175      }
1176      
1177      /** 
1178       * Set the value of the <code>name</code> property to a <code>long</code>.
1179       * 
1180       * @param name property name.
1181       * @param value <code>long</code> value of the property.
1182       */
1183      public void setLong(String name, long value) {
1184        set(name, Long.toString(value));
1185      }
1186    
1187      /** 
1188       * Get the value of the <code>name</code> property as a <code>float</code>.  
1189       * If no such property exists, the provided default value is returned,
1190       * or if the specified value is not a valid <code>float</code>,
1191       * then an error is thrown.
1192       *
1193       * @param name property name.
1194       * @param defaultValue default value.
1195       * @throws NumberFormatException when the value is invalid
1196       * @return property value as a <code>float</code>, 
1197       *         or <code>defaultValue</code>. 
1198       */
1199      public float getFloat(String name, float defaultValue) {
1200        String valueString = getTrimmed(name);
1201        if (valueString == null)
1202          return defaultValue;
1203        return Float.parseFloat(valueString);
1204      }
1205    
1206      /**
1207       * Set the value of the <code>name</code> property to a <code>float</code>.
1208       * 
1209       * @param name property name.
1210       * @param value property value.
1211       */
1212      public void setFloat(String name, float value) {
1213        set(name,Float.toString(value));
1214      }
1215    
1216      /** 
1217       * Get the value of the <code>name</code> property as a <code>double</code>.  
1218       * If no such property exists, the provided default value is returned,
1219       * or if the specified value is not a valid <code>double</code>,
1220       * then an error is thrown.
1221       *
1222       * @param name property name.
1223       * @param defaultValue default value.
1224       * @throws NumberFormatException when the value is invalid
1225       * @return property value as a <code>double</code>, 
1226       *         or <code>defaultValue</code>. 
1227       */
1228      public double getDouble(String name, double defaultValue) {
1229        String valueString = getTrimmed(name);
1230        if (valueString == null)
1231          return defaultValue;
1232        return Double.parseDouble(valueString);
1233      }
1234    
1235      /**
1236       * Set the value of the <code>name</code> property to a <code>double</code>.
1237       * 
1238       * @param name property name.
1239       * @param value property value.
1240       */
1241      public void setDouble(String name, double value) {
1242        set(name,Double.toString(value));
1243      }
1244     
1245      /** 
1246       * Get the value of the <code>name</code> property as a <code>boolean</code>.  
1247       * If no such property is specified, or if the specified value is not a valid
1248       * <code>boolean</code>, then <code>defaultValue</code> is returned.
1249       * 
1250       * @param name property name.
1251       * @param defaultValue default value.
1252       * @return property value as a <code>boolean</code>, 
1253       *         or <code>defaultValue</code>. 
1254       */
1255      public boolean getBoolean(String name, boolean defaultValue) {
1256        String valueString = getTrimmed(name);
1257        if (null == valueString || valueString.isEmpty()) {
1258          return defaultValue;
1259        }
1260    
1261        valueString = valueString.toLowerCase();
1262    
1263        if ("true".equals(valueString))
1264          return true;
1265        else if ("false".equals(valueString))
1266          return false;
1267        else return defaultValue;
1268      }
1269    
1270      /** 
1271       * Set the value of the <code>name</code> property to a <code>boolean</code>.
1272       * 
1273       * @param name property name.
1274       * @param value <code>boolean</code> value of the property.
1275       */
1276      public void setBoolean(String name, boolean value) {
1277        set(name, Boolean.toString(value));
1278      }
1279    
1280      /**
1281       * Set the given property, if it is currently unset.
1282       * @param name property name
1283       * @param value new value
1284       */
1285      public void setBooleanIfUnset(String name, boolean value) {
1286        setIfUnset(name, Boolean.toString(value));
1287      }
1288    
1289      /**
1290       * Set the value of the <code>name</code> property to the given type. This
1291       * is equivalent to <code>set(&lt;name&gt;, value.toString())</code>.
1292       * @param name property name
1293       * @param value new value
1294       */
1295      public <T extends Enum<T>> void setEnum(String name, T value) {
1296        set(name, value.toString());
1297      }
1298    
1299      /**
1300       * Return value matching this enumerated type.
1301       * @param name Property name
1302       * @param defaultValue Value returned if no mapping exists
1303       * @throws IllegalArgumentException If mapping is illegal for the type
1304       * provided
1305       */
1306      public <T extends Enum<T>> T getEnum(String name, T defaultValue) {
1307        final String val = get(name);
1308        return null == val
1309          ? defaultValue
1310          : Enum.valueOf(defaultValue.getDeclaringClass(), val);
1311      }
1312    
1313      enum ParsedTimeDuration {
1314        NS {
1315          TimeUnit unit() { return TimeUnit.NANOSECONDS; }
1316          String suffix() { return "ns"; }
1317        },
1318        US {
1319          TimeUnit unit() { return TimeUnit.MICROSECONDS; }
1320          String suffix() { return "us"; }
1321        },
1322        MS {
1323          TimeUnit unit() { return TimeUnit.MILLISECONDS; }
1324          String suffix() { return "ms"; }
1325        },
1326        S {
1327          TimeUnit unit() { return TimeUnit.SECONDS; }
1328          String suffix() { return "s"; }
1329        },
1330        M {
1331          TimeUnit unit() { return TimeUnit.MINUTES; }
1332          String suffix() { return "m"; }
1333        },
1334        H {
1335          TimeUnit unit() { return TimeUnit.HOURS; }
1336          String suffix() { return "h"; }
1337        },
1338        D {
1339          TimeUnit unit() { return TimeUnit.DAYS; }
1340          String suffix() { return "d"; }
1341        };
1342        abstract TimeUnit unit();
1343        abstract String suffix();
1344        static ParsedTimeDuration unitFor(String s) {
1345          for (ParsedTimeDuration ptd : values()) {
1346            // iteration order is in decl order, so SECONDS matched last
1347            if (s.endsWith(ptd.suffix())) {
1348              return ptd;
1349            }
1350          }
1351          return null;
1352        }
1353        static ParsedTimeDuration unitFor(TimeUnit unit) {
1354          for (ParsedTimeDuration ptd : values()) {
1355            if (ptd.unit() == unit) {
1356              return ptd;
1357            }
1358          }
1359          return null;
1360        }
1361      }
1362    
1363      /**
1364       * Set the value of <code>name</code> to the given time duration. This
1365       * is equivalent to <code>set(&lt;name&gt;, value + &lt;time suffix&gt;)</code>.
1366       * @param name Property name
1367       * @param value Time duration
1368       * @param unit Unit of time
1369       */
1370      public void setTimeDuration(String name, long value, TimeUnit unit) {
1371        set(name, value + ParsedTimeDuration.unitFor(unit).suffix());
1372      }
1373    
1374      /**
1375       * Return time duration in the given time unit. Valid units are encoded in
1376       * properties as suffixes: nanoseconds (ns), microseconds (us), milliseconds
1377       * (ms), seconds (s), minutes (m), hours (h), and days (d).
1378       * @param name Property name
1379       * @param defaultValue Value returned if no mapping exists.
1380       * @param unit Unit to convert the stored property, if it exists.
1381       * @throws NumberFormatException If the property stripped of its unit is not
1382       *         a number
1383       */
1384      public long getTimeDuration(String name, long defaultValue, TimeUnit unit) {
1385        String vStr = get(name);
1386        if (null == vStr) {
1387          return defaultValue;
1388        }
1389        vStr = vStr.trim();
1390        ParsedTimeDuration vUnit = ParsedTimeDuration.unitFor(vStr);
1391        if (null == vUnit) {
1392          LOG.warn("No unit for " + name + "(" + vStr + ") assuming " + unit);
1393          vUnit = ParsedTimeDuration.unitFor(unit);
1394        } else {
1395          vStr = vStr.substring(0, vStr.lastIndexOf(vUnit.suffix()));
1396        }
1397        return unit.convert(Long.parseLong(vStr), vUnit.unit());
1398      }
1399    
1400      /**
1401       * Get the value of the <code>name</code> property as a <code>Pattern</code>.
1402       * If no such property is specified, or if the specified value is not a valid
1403       * <code>Pattern</code>, then <code>DefaultValue</code> is returned.
1404       *
1405       * @param name property name
1406       * @param defaultValue default value
1407       * @return property value as a compiled Pattern, or defaultValue
1408       */
1409      public Pattern getPattern(String name, Pattern defaultValue) {
1410        String valString = get(name);
1411        if (null == valString || valString.isEmpty()) {
1412          return defaultValue;
1413        }
1414        try {
1415          return Pattern.compile(valString);
1416        } catch (PatternSyntaxException pse) {
1417          LOG.warn("Regular expression '" + valString + "' for property '" +
1418                   name + "' not valid. Using default", pse);
1419          return defaultValue;
1420        }
1421      }
1422    
1423      /**
1424       * Set the given property to <code>Pattern</code>.
1425       * If the pattern is passed as null, sets the empty pattern which results in
1426       * further calls to getPattern(...) returning the default value.
1427       *
1428       * @param name property name
1429       * @param pattern new value
1430       */
1431      public void setPattern(String name, Pattern pattern) {
1432        if (null == pattern) {
1433          set(name, null);
1434        } else {
1435          set(name, pattern.pattern());
1436        }
1437      }
1438    
1439      /**
1440       * Gets information about why a property was set.  Typically this is the 
1441       * path to the resource objects (file, URL, etc.) the property came from, but
1442       * it can also indicate that it was set programatically, or because of the
1443       * command line.
1444       *
1445       * @param name - The property name to get the source of.
1446       * @return null - If the property or its source wasn't found. Otherwise, 
1447       * returns a list of the sources of the resource.  The older sources are
1448       * the first ones in the list.  So for example if a configuration is set from
1449       * the command line, and then written out to a file that is read back in the
1450       * first entry would indicate that it was set from the command line, while
1451       * the second one would indicate the file that the new configuration was read
1452       * in from.
1453       */
1454      @InterfaceStability.Unstable
1455      public synchronized String[] getPropertySources(String name) {
1456        if (properties == null) {
1457          // If properties is null, it means a resource was newly added
1458          // but the props were cleared so as to load it upon future
1459          // requests. So lets force a load by asking a properties list.
1460          getProps();
1461        }
1462        // Return a null right away if our properties still
1463        // haven't loaded or the resource mapping isn't defined
1464        if (properties == null || updatingResource == null) {
1465          return null;
1466        } else {
1467          String[] source = updatingResource.get(name);
1468          if(source == null) {
1469            return null;
1470          } else {
1471            return Arrays.copyOf(source, source.length);
1472          }
1473        }
1474      }
1475    
1476      /**
1477       * A class that represents a set of positive integer ranges. It parses 
1478       * strings of the form: "2-3,5,7-" where ranges are separated by comma and 
1479       * the lower/upper bounds are separated by dash. Either the lower or upper 
1480       * bound may be omitted meaning all values up to or over. So the string 
1481       * above means 2, 3, 5, and 7, 8, 9, ...
1482       */
1483      public static class IntegerRanges implements Iterable<Integer>{
1484        private static class Range {
1485          int start;
1486          int end;
1487        }
1488        
1489        private static class RangeNumberIterator implements Iterator<Integer> {
1490          Iterator<Range> internal;
1491          int at;
1492          int end;
1493    
1494          public RangeNumberIterator(List<Range> ranges) {
1495            if (ranges != null) {
1496              internal = ranges.iterator();
1497            }
1498            at = -1;
1499            end = -2;
1500          }
1501          
1502          @Override
1503          public boolean hasNext() {
1504            if (at <= end) {
1505              return true;
1506            } else if (internal != null){
1507              return internal.hasNext();
1508            }
1509            return false;
1510          }
1511    
1512          @Override
1513          public Integer next() {
1514            if (at <= end) {
1515              at++;
1516              return at - 1;
1517            } else if (internal != null){
1518              Range found = internal.next();
1519              if (found != null) {
1520                at = found.start;
1521                end = found.end;
1522                at++;
1523                return at - 1;
1524              }
1525            }
1526            return null;
1527          }
1528    
1529          @Override
1530          public void remove() {
1531            throw new UnsupportedOperationException();
1532          }
1533        };
1534    
1535        List<Range> ranges = new ArrayList<Range>();
1536        
1537        public IntegerRanges() {
1538        }
1539        
1540        public IntegerRanges(String newValue) {
1541          StringTokenizer itr = new StringTokenizer(newValue, ",");
1542          while (itr.hasMoreTokens()) {
1543            String rng = itr.nextToken().trim();
1544            String[] parts = rng.split("-", 3);
1545            if (parts.length < 1 || parts.length > 2) {
1546              throw new IllegalArgumentException("integer range badly formed: " + 
1547                                                 rng);
1548            }
1549            Range r = new Range();
1550            r.start = convertToInt(parts[0], 0);
1551            if (parts.length == 2) {
1552              r.end = convertToInt(parts[1], Integer.MAX_VALUE);
1553            } else {
1554              r.end = r.start;
1555            }
1556            if (r.start > r.end) {
1557              throw new IllegalArgumentException("IntegerRange from " + r.start + 
1558                                                 " to " + r.end + " is invalid");
1559            }
1560            ranges.add(r);
1561          }
1562        }
1563    
1564        /**
1565         * Convert a string to an int treating empty strings as the default value.
1566         * @param value the string value
1567         * @param defaultValue the value for if the string is empty
1568         * @return the desired integer
1569         */
1570        private static int convertToInt(String value, int defaultValue) {
1571          String trim = value.trim();
1572          if (trim.length() == 0) {
1573            return defaultValue;
1574          }
1575          return Integer.parseInt(trim);
1576        }
1577    
1578        /**
1579         * Is the given value in the set of ranges
1580         * @param value the value to check
1581         * @return is the value in the ranges?
1582         */
1583        public boolean isIncluded(int value) {
1584          for(Range r: ranges) {
1585            if (r.start <= value && value <= r.end) {
1586              return true;
1587            }
1588          }
1589          return false;
1590        }
1591        
1592        /**
1593         * @return true if there are no values in this range, else false.
1594         */
1595        public boolean isEmpty() {
1596          return ranges == null || ranges.isEmpty();
1597        }
1598        
1599        @Override
1600        public String toString() {
1601          StringBuilder result = new StringBuilder();
1602          boolean first = true;
1603          for(Range r: ranges) {
1604            if (first) {
1605              first = false;
1606            } else {
1607              result.append(',');
1608            }
1609            result.append(r.start);
1610            result.append('-');
1611            result.append(r.end);
1612          }
1613          return result.toString();
1614        }
1615    
1616        @Override
1617        public Iterator<Integer> iterator() {
1618          return new RangeNumberIterator(ranges);
1619        }
1620        
1621      }
1622    
1623      /**
1624       * Parse the given attribute as a set of integer ranges
1625       * @param name the attribute name
1626       * @param defaultValue the default value if it is not set
1627       * @return a new set of ranges from the configured value
1628       */
1629      public IntegerRanges getRange(String name, String defaultValue) {
1630        return new IntegerRanges(get(name, defaultValue));
1631      }
1632    
1633      /** 
1634       * Get the comma delimited values of the <code>name</code> property as 
1635       * a collection of <code>String</code>s.  
1636       * If no such property is specified then empty collection is returned.
1637       * <p>
1638       * This is an optimized version of {@link #getStrings(String)}
1639       * 
1640       * @param name property name.
1641       * @return property value as a collection of <code>String</code>s. 
1642       */
1643      public Collection<String> getStringCollection(String name) {
1644        String valueString = get(name);
1645        return StringUtils.getStringCollection(valueString);
1646      }
1647    
1648      /** 
1649       * Get the comma delimited values of the <code>name</code> property as 
1650       * an array of <code>String</code>s.  
1651       * If no such property is specified then <code>null</code> is returned.
1652       * 
1653       * @param name property name.
1654       * @return property value as an array of <code>String</code>s, 
1655       *         or <code>null</code>. 
1656       */
1657      public String[] getStrings(String name) {
1658        String valueString = get(name);
1659        return StringUtils.getStrings(valueString);
1660      }
1661    
1662      /** 
1663       * Get the comma delimited values of the <code>name</code> property as 
1664       * an array of <code>String</code>s.  
1665       * If no such property is specified then default value is returned.
1666       * 
1667       * @param name property name.
1668       * @param defaultValue The default value
1669       * @return property value as an array of <code>String</code>s, 
1670       *         or default value. 
1671       */
1672      public String[] getStrings(String name, String... defaultValue) {
1673        String valueString = get(name);
1674        if (valueString == null) {
1675          return defaultValue;
1676        } else {
1677          return StringUtils.getStrings(valueString);
1678        }
1679      }
1680      
1681      /** 
1682       * Get the comma delimited values of the <code>name</code> property as 
1683       * a collection of <code>String</code>s, trimmed of the leading and trailing whitespace.  
1684       * If no such property is specified then empty <code>Collection</code> is returned.
1685       *
1686       * @param name property name.
1687       * @return property value as a collection of <code>String</code>s, or empty <code>Collection</code> 
1688       */
1689      public Collection<String> getTrimmedStringCollection(String name) {
1690        String valueString = get(name);
1691        if (null == valueString) {
1692          Collection<String> empty = new ArrayList<String>();
1693          return empty;
1694        }
1695        return StringUtils.getTrimmedStringCollection(valueString);
1696      }
1697      
1698      /** 
1699       * Get the comma delimited values of the <code>name</code> property as 
1700       * an array of <code>String</code>s, trimmed of the leading and trailing whitespace.
1701       * If no such property is specified then an empty array is returned.
1702       * 
1703       * @param name property name.
1704       * @return property value as an array of trimmed <code>String</code>s, 
1705       *         or empty array. 
1706       */
1707      public String[] getTrimmedStrings(String name) {
1708        String valueString = get(name);
1709        return StringUtils.getTrimmedStrings(valueString);
1710      }
1711    
1712      /** 
1713       * Get the comma delimited values of the <code>name</code> property as 
1714       * an array of <code>String</code>s, trimmed of the leading and trailing whitespace.
1715       * If no such property is specified then default value is returned.
1716       * 
1717       * @param name property name.
1718       * @param defaultValue The default value
1719       * @return property value as an array of trimmed <code>String</code>s, 
1720       *         or default value. 
1721       */
1722      public String[] getTrimmedStrings(String name, String... defaultValue) {
1723        String valueString = get(name);
1724        if (null == valueString) {
1725          return defaultValue;
1726        } else {
1727          return StringUtils.getTrimmedStrings(valueString);
1728        }
1729      }
1730    
1731      /** 
1732       * Set the array of string values for the <code>name</code> property as 
1733       * as comma delimited values.  
1734       * 
1735       * @param name property name.
1736       * @param values The values
1737       */
1738      public void setStrings(String name, String... values) {
1739        set(name, StringUtils.arrayToString(values));
1740      }
1741    
1742      /**
1743       * Get the socket address for <code>name</code> property as a
1744       * <code>InetSocketAddress</code>.
1745       * @param name property name.
1746       * @param defaultAddress the default value
1747       * @param defaultPort the default port
1748       * @return InetSocketAddress
1749       */
1750      public InetSocketAddress getSocketAddr(
1751          String name, String defaultAddress, int defaultPort) {
1752        final String address = get(name, defaultAddress);
1753        return NetUtils.createSocketAddr(address, defaultPort, name);
1754      }
1755    
1756      /**
1757       * Set the socket address for the <code>name</code> property as
1758       * a <code>host:port</code>.
1759       */
1760      public void setSocketAddr(String name, InetSocketAddress addr) {
1761        set(name, NetUtils.getHostPortString(addr));
1762      }
1763      
1764      /**
1765       * Set the socket address a client can use to connect for the
1766       * <code>name</code> property as a <code>host:port</code>.  The wildcard
1767       * address is replaced with the local host's address.
1768       * @param name property name.
1769       * @param addr InetSocketAddress of a listener to store in the given property
1770       * @return InetSocketAddress for clients to connect
1771       */
1772      public InetSocketAddress updateConnectAddr(String name,
1773                                                 InetSocketAddress addr) {
1774        final InetSocketAddress connectAddr = NetUtils.getConnectAddress(addr);
1775        setSocketAddr(name, connectAddr);
1776        return connectAddr;
1777      }
1778      
1779      /**
1780       * Load a class by name.
1781       * 
1782       * @param name the class name.
1783       * @return the class object.
1784       * @throws ClassNotFoundException if the class is not found.
1785       */
1786      public Class<?> getClassByName(String name) throws ClassNotFoundException {
1787        Class<?> ret = getClassByNameOrNull(name);
1788        if (ret == null) {
1789          throw new ClassNotFoundException("Class " + name + " not found");
1790        }
1791        return ret;
1792      }
1793      
1794      /**
1795       * Load a class by name, returning null rather than throwing an exception
1796       * if it couldn't be loaded. This is to avoid the overhead of creating
1797       * an exception.
1798       * 
1799       * @param name the class name
1800       * @return the class object, or null if it could not be found.
1801       */
1802      public Class<?> getClassByNameOrNull(String name) {
1803        Map<String, WeakReference<Class<?>>> map;
1804        
1805        synchronized (CACHE_CLASSES) {
1806          map = CACHE_CLASSES.get(classLoader);
1807          if (map == null) {
1808            map = Collections.synchronizedMap(
1809              new WeakHashMap<String, WeakReference<Class<?>>>());
1810            CACHE_CLASSES.put(classLoader, map);
1811          }
1812        }
1813    
1814        Class<?> clazz = null;
1815        WeakReference<Class<?>> ref = map.get(name); 
1816        if (ref != null) {
1817           clazz = ref.get();
1818        }
1819         
1820        if (clazz == null) {
1821          try {
1822            clazz = Class.forName(name, true, classLoader);
1823          } catch (ClassNotFoundException e) {
1824            // Leave a marker that the class isn't found
1825            map.put(name, new WeakReference<Class<?>>(NEGATIVE_CACHE_SENTINEL));
1826            return null;
1827          }
1828          // two putters can race here, but they'll put the same class
1829          map.put(name, new WeakReference<Class<?>>(clazz));
1830          return clazz;
1831        } else if (clazz == NEGATIVE_CACHE_SENTINEL) {
1832          return null; // not found
1833        } else {
1834          // cache hit
1835          return clazz;
1836        }
1837      }
1838    
1839      /** 
1840       * Get the value of the <code>name</code> property
1841       * as an array of <code>Class</code>.
1842       * The value of the property specifies a list of comma separated class names.  
1843       * If no such property is specified, then <code>defaultValue</code> is 
1844       * returned.
1845       * 
1846       * @param name the property name.
1847       * @param defaultValue default value.
1848       * @return property value as a <code>Class[]</code>, 
1849       *         or <code>defaultValue</code>. 
1850       */
1851      public Class<?>[] getClasses(String name, Class<?> ... defaultValue) {
1852        String[] classnames = getTrimmedStrings(name);
1853        if (classnames == null)
1854          return defaultValue;
1855        try {
1856          Class<?>[] classes = new Class<?>[classnames.length];
1857          for(int i = 0; i < classnames.length; i++) {
1858            classes[i] = getClassByName(classnames[i]);
1859          }
1860          return classes;
1861        } catch (ClassNotFoundException e) {
1862          throw new RuntimeException(e);
1863        }
1864      }
1865    
1866      /** 
1867       * Get the value of the <code>name</code> property as a <code>Class</code>.  
1868       * If no such property is specified, then <code>defaultValue</code> is 
1869       * returned.
1870       * 
1871       * @param name the class name.
1872       * @param defaultValue default value.
1873       * @return property value as a <code>Class</code>, 
1874       *         or <code>defaultValue</code>. 
1875       */
1876      public Class<?> getClass(String name, Class<?> defaultValue) {
1877        String valueString = getTrimmed(name);
1878        if (valueString == null)
1879          return defaultValue;
1880        try {
1881          return getClassByName(valueString);
1882        } catch (ClassNotFoundException e) {
1883          throw new RuntimeException(e);
1884        }
1885      }
1886    
1887      /** 
1888       * Get the value of the <code>name</code> property as a <code>Class</code>
1889       * implementing the interface specified by <code>xface</code>.
1890       *   
1891       * If no such property is specified, then <code>defaultValue</code> is 
1892       * returned.
1893       * 
1894       * An exception is thrown if the returned class does not implement the named
1895       * interface. 
1896       * 
1897       * @param name the class name.
1898       * @param defaultValue default value.
1899       * @param xface the interface implemented by the named class.
1900       * @return property value as a <code>Class</code>, 
1901       *         or <code>defaultValue</code>.
1902       */
1903      public <U> Class<? extends U> getClass(String name, 
1904                                             Class<? extends U> defaultValue, 
1905                                             Class<U> xface) {
1906        try {
1907          Class<?> theClass = getClass(name, defaultValue);
1908          if (theClass != null && !xface.isAssignableFrom(theClass))
1909            throw new RuntimeException(theClass+" not "+xface.getName());
1910          else if (theClass != null)
1911            return theClass.asSubclass(xface);
1912          else
1913            return null;
1914        } catch (Exception e) {
1915          throw new RuntimeException(e);
1916        }
1917      }
1918    
1919      /**
1920       * Get the value of the <code>name</code> property as a <code>List</code>
1921       * of objects implementing the interface specified by <code>xface</code>.
1922       * 
1923       * An exception is thrown if any of the classes does not exist, or if it does
1924       * not implement the named interface.
1925       * 
1926       * @param name the property name.
1927       * @param xface the interface implemented by the classes named by
1928       *        <code>name</code>.
1929       * @return a <code>List</code> of objects implementing <code>xface</code>.
1930       */
1931      @SuppressWarnings("unchecked")
1932      public <U> List<U> getInstances(String name, Class<U> xface) {
1933        List<U> ret = new ArrayList<U>();
1934        Class<?>[] classes = getClasses(name);
1935        for (Class<?> cl: classes) {
1936          if (!xface.isAssignableFrom(cl)) {
1937            throw new RuntimeException(cl + " does not implement " + xface);
1938          }
1939          ret.add((U)ReflectionUtils.newInstance(cl, this));
1940        }
1941        return ret;
1942      }
1943    
1944      /** 
1945       * Set the value of the <code>name</code> property to the name of a 
1946       * <code>theClass</code> implementing the given interface <code>xface</code>.
1947       * 
1948       * An exception is thrown if <code>theClass</code> does not implement the 
1949       * interface <code>xface</code>. 
1950       * 
1951       * @param name property name.
1952       * @param theClass property value.
1953       * @param xface the interface implemented by the named class.
1954       */
1955      public void setClass(String name, Class<?> theClass, Class<?> xface) {
1956        if (!xface.isAssignableFrom(theClass))
1957          throw new RuntimeException(theClass+" not "+xface.getName());
1958        set(name, theClass.getName());
1959      }
1960    
1961      /** 
1962       * Get a local file under a directory named by <i>dirsProp</i> with
1963       * the given <i>path</i>.  If <i>dirsProp</i> contains multiple directories,
1964       * then one is chosen based on <i>path</i>'s hash code.  If the selected
1965       * directory does not exist, an attempt is made to create it.
1966       * 
1967       * @param dirsProp directory in which to locate the file.
1968       * @param path file-path.
1969       * @return local file under the directory with the given path.
1970       */
1971      public Path getLocalPath(String dirsProp, String path)
1972        throws IOException {
1973        String[] dirs = getTrimmedStrings(dirsProp);
1974        int hashCode = path.hashCode();
1975        FileSystem fs = FileSystem.getLocal(this);
1976        for (int i = 0; i < dirs.length; i++) {  // try each local dir
1977          int index = (hashCode+i & Integer.MAX_VALUE) % dirs.length;
1978          Path file = new Path(dirs[index], path);
1979          Path dir = file.getParent();
1980          if (fs.mkdirs(dir) || fs.exists(dir)) {
1981            return file;
1982          }
1983        }
1984        LOG.warn("Could not make " + path + 
1985                 " in local directories from " + dirsProp);
1986        for(int i=0; i < dirs.length; i++) {
1987          int index = (hashCode+i & Integer.MAX_VALUE) % dirs.length;
1988          LOG.warn(dirsProp + "[" + index + "]=" + dirs[index]);
1989        }
1990        throw new IOException("No valid local directories in property: "+dirsProp);
1991      }
1992    
1993      /** 
1994       * Get a local file name under a directory named in <i>dirsProp</i> with
1995       * the given <i>path</i>.  If <i>dirsProp</i> contains multiple directories,
1996       * then one is chosen based on <i>path</i>'s hash code.  If the selected
1997       * directory does not exist, an attempt is made to create it.
1998       * 
1999       * @param dirsProp directory in which to locate the file.
2000       * @param path file-path.
2001       * @return local file under the directory with the given path.
2002       */
2003      public File getFile(String dirsProp, String path)
2004        throws IOException {
2005        String[] dirs = getTrimmedStrings(dirsProp);
2006        int hashCode = path.hashCode();
2007        for (int i = 0; i < dirs.length; i++) {  // try each local dir
2008          int index = (hashCode+i & Integer.MAX_VALUE) % dirs.length;
2009          File file = new File(dirs[index], path);
2010          File dir = file.getParentFile();
2011          if (dir.exists() || dir.mkdirs()) {
2012            return file;
2013          }
2014        }
2015        throw new IOException("No valid local directories in property: "+dirsProp);
2016      }
2017    
2018      /** 
2019       * Get the {@link URL} for the named resource.
2020       * 
2021       * @param name resource name.
2022       * @return the url for the named resource.
2023       */
2024      public URL getResource(String name) {
2025        return classLoader.getResource(name);
2026      }
2027    
2028      /**
2029       * Checks if the class specified by propertiesClassName is found on the classLoader.
2030       * If yes, creates an instance of the class and checks if the instance is of type {@link java.util.Properties}.
2031       *
2032       * @param propertiesClassName class name.
2033       * @return instance of {@link Properties} if successful. Returns null otherwise.
2034       */
2035      public Properties getProperties(String propertiesClassName) {
2036        try {
2037          Class<?> propertiesClass = getClassByNameOrNull(propertiesClassName);
2038          if (propertiesClass != null) {
2039            Object propertiesObj = propertiesClass.newInstance();
2040            if (propertiesObj instanceof Properties) {
2041              if (LOG.isDebugEnabled()) {
2042                LOG.debug("Loaded " + propertiesClass.getName());
2043              }
2044              return (Properties) propertiesObj;
2045            }
2046          }
2047        } catch (InstantiationException e) {
2048        } catch (IllegalAccessException e) {
2049        }
2050    
2051        return null;
2052      }
2053    
2054      /** 
2055       * Get an input stream attached to the configuration resource with the
2056       * given <code>name</code>.
2057       * 
2058       * @param name configuration resource name.
2059       * @return an input stream attached to the resource.
2060       */
2061      public InputStream getConfResourceAsInputStream(String name) {
2062        try {
2063          URL url= getResource(name);
2064    
2065          if (url == null) {
2066            LOG.info(name + " not found");
2067            return null;
2068          } else {
2069            LOG.info("found resource " + name + " at " + url);
2070          }
2071    
2072          return url.openStream();
2073        } catch (Exception e) {
2074          return null;
2075        }
2076      }
2077    
2078      /** 
2079       * Get a {@link Reader} attached to the configuration resource with the
2080       * given <code>name</code>.
2081       * 
2082       * @param name configuration resource name.
2083       * @return a reader attached to the resource.
2084       */
2085      public Reader getConfResourceAsReader(String name) {
2086        try {
2087          URL url= getResource(name);
2088    
2089          if (url == null) {
2090            LOG.info(name + " not found");
2091            return null;
2092          } else {
2093            LOG.info("found resource " + name + " at " + url);
2094          }
2095    
2096          return new InputStreamReader(url.openStream());
2097        } catch (Exception e) {
2098          return null;
2099        }
2100      }
2101    
2102      protected synchronized Properties getProps() {
2103        if (properties == null) {
2104          properties = new Properties();
2105          HashMap<String, String[]> backup = 
2106            new HashMap<String, String[]>(updatingResource);
2107          loadResources(properties, resources, quietmode);
2108          if (overlay!= null) {
2109            properties.putAll(overlay);
2110            for (Map.Entry<Object,Object> item: overlay.entrySet()) {
2111              String key = (String)item.getKey();
2112              updatingResource.put(key, backup.get(key));
2113            }
2114          }
2115        }
2116        return properties;
2117      }
2118    
2119      /**
2120       * Return the number of keys in the configuration.
2121       *
2122       * @return number of keys in the configuration.
2123       */
2124      public int size() {
2125        return getProps().size();
2126      }
2127    
2128      /**
2129       * Clears all keys from the configuration.
2130       */
2131      public void clear() {
2132        getProps().clear();
2133        getOverlay().clear();
2134      }
2135    
2136      /**
2137       * Get an {@link Iterator} to go through the list of <code>String</code> 
2138       * key-value pairs in the configuration.
2139       * 
2140       * @return an iterator over the entries.
2141       */
2142      @Override
2143      public Iterator<Map.Entry<String, String>> iterator() {
2144        // Get a copy of just the string to string pairs. After the old object
2145        // methods that allow non-strings to be put into configurations are removed,
2146        // we could replace properties with a Map<String,String> and get rid of this
2147        // code.
2148        Map<String,String> result = new HashMap<String,String>();
2149        for(Map.Entry<Object,Object> item: getProps().entrySet()) {
2150          if (item.getKey() instanceof String && 
2151              item.getValue() instanceof String) {
2152            result.put((String) item.getKey(), (String) item.getValue());
2153          }
2154        }
2155        return result.entrySet().iterator();
2156      }
2157    
2158      private Document parse(DocumentBuilder builder, URL url)
2159          throws IOException, SAXException {
2160        if (!quietmode) {
2161          LOG.info("parsing URL " + url);
2162        }
2163        if (url == null) {
2164          return null;
2165        }
2166        return parse(builder, url.openStream(), url.toString());
2167      }
2168    
2169      private Document parse(DocumentBuilder builder, InputStream is,
2170          String systemId) throws IOException, SAXException {
2171        if (!quietmode) {
2172          LOG.info("parsing input stream " + is);
2173        }
2174        if (is == null) {
2175          return null;
2176        }
2177        try {
2178          return (systemId == null) ? builder.parse(is) : builder.parse(is,
2179              systemId);
2180        } finally {
2181          is.close();
2182        }
2183      }
2184    
2185      private void loadResources(Properties properties,
2186                                 ArrayList<Resource> resources,
2187                                 boolean quiet) {
2188        if(loadDefaults) {
2189          for (String resource : defaultResources) {
2190            loadResource(properties, new Resource(resource), quiet);
2191          }
2192        
2193          //support the hadoop-site.xml as a deprecated case
2194          if(getResource("hadoop-site.xml")!=null) {
2195            loadResource(properties, new Resource("hadoop-site.xml"), quiet);
2196          }
2197        }
2198        
2199        for (int i = 0; i < resources.size(); i++) {
2200          Resource ret = loadResource(properties, resources.get(i), quiet);
2201          if (ret != null) {
2202            resources.set(i, ret);
2203          }
2204        }
2205      }
2206      
2207      private Resource loadResource(Properties properties, Resource wrapper, boolean quiet) {
2208        String name = UNKNOWN_RESOURCE;
2209        try {
2210          Object resource = wrapper.getResource();
2211          name = wrapper.getName();
2212          
2213          DocumentBuilderFactory docBuilderFactory 
2214            = DocumentBuilderFactory.newInstance();
2215          //ignore all comments inside the xml file
2216          docBuilderFactory.setIgnoringComments(true);
2217    
2218          //allow includes in the xml file
2219          docBuilderFactory.setNamespaceAware(true);
2220          try {
2221              docBuilderFactory.setXIncludeAware(true);
2222          } catch (UnsupportedOperationException e) {
2223            LOG.error("Failed to set setXIncludeAware(true) for parser "
2224                    + docBuilderFactory
2225                    + ":" + e,
2226                    e);
2227          }
2228          DocumentBuilder builder = docBuilderFactory.newDocumentBuilder();
2229          Document doc = null;
2230          Element root = null;
2231          boolean returnCachedProperties = false;
2232          
2233          if (resource instanceof URL) {                  // an URL resource
2234            doc = parse(builder, (URL)resource);
2235          } else if (resource instanceof String) {        // a CLASSPATH resource
2236            String resourceStr = (String) resource;
2237            Properties props = null;
2238            if (!resourceStr.endsWith(".xml") && (props = getProperties(resourceStr)) != null) {
2239              overlay(properties, props);
2240            } else {
2241              URL url = getResource(resourceStr);
2242              doc = parse(builder, url);
2243            }
2244          } else if (resource instanceof Path) {          // a file resource
2245            // Can't use FileSystem API or we get an infinite loop
2246            // since FileSystem uses Configuration API.  Use java.io.File instead.
2247            File file = new File(((Path)resource).toUri().getPath())
2248              .getAbsoluteFile();
2249            if (file.exists()) {
2250              if (!quiet) {
2251                LOG.info("parsing File " + file);
2252              }
2253              doc = parse(builder, new BufferedInputStream(
2254                  new FileInputStream(file)), ((Path)resource).toString());
2255            }
2256          } else if (resource instanceof InputStream) {
2257            doc = parse(builder, (InputStream) resource, null);
2258            returnCachedProperties = true;
2259          } else if (resource instanceof Properties) {
2260            overlay(properties, (Properties)resource);
2261          } else if (resource instanceof Element) {
2262            root = (Element)resource;
2263          }
2264    
2265          if (doc == null && root == null) {
2266            if (quiet)
2267              return null;
2268            throw new RuntimeException(resource + " not found");
2269          }
2270    
2271          if (root == null) {
2272            root = doc.getDocumentElement();
2273          }
2274          Properties toAddTo = properties;
2275          if(returnCachedProperties) {
2276            toAddTo = new Properties();
2277          }
2278          if (!"configuration".equals(root.getTagName()))
2279            LOG.fatal("bad conf file: top-level element not <configuration>");
2280          NodeList props = root.getChildNodes();
2281          DeprecationContext deprecations = deprecationContext.get();
2282          for (int i = 0; i < props.getLength(); i++) {
2283            Node propNode = props.item(i);
2284            if (!(propNode instanceof Element))
2285              continue;
2286            Element prop = (Element)propNode;
2287            if ("configuration".equals(prop.getTagName())) {
2288              loadResource(toAddTo, new Resource(prop, name), quiet);
2289              continue;
2290            }
2291            if (!"property".equals(prop.getTagName()))
2292              LOG.warn("bad conf file: element not <property>");
2293            NodeList fields = prop.getChildNodes();
2294            String attr = null;
2295            String value = null;
2296            boolean finalParameter = false;
2297            LinkedList<String> source = new LinkedList<String>();
2298            for (int j = 0; j < fields.getLength(); j++) {
2299              Node fieldNode = fields.item(j);
2300              if (!(fieldNode instanceof Element))
2301                continue;
2302              Element field = (Element)fieldNode;
2303              if ("name".equals(field.getTagName()) && field.hasChildNodes())
2304                attr = StringInterner.weakIntern(
2305                    ((Text)field.getFirstChild()).getData().trim());
2306              if ("value".equals(field.getTagName()) && field.hasChildNodes())
2307                value = StringInterner.weakIntern(
2308                    ((Text)field.getFirstChild()).getData());
2309              if ("final".equals(field.getTagName()) && field.hasChildNodes())
2310                finalParameter = "true".equals(((Text)field.getFirstChild()).getData());
2311              if ("source".equals(field.getTagName()) && field.hasChildNodes())
2312                source.add(StringInterner.weakIntern(
2313                    ((Text)field.getFirstChild()).getData()));
2314            }
2315            source.add(name);
2316            
2317            // Ignore this parameter if it has already been marked as 'final'
2318            if (attr != null) {
2319              if (deprecations.getDeprecatedKeyMap().containsKey(attr)) {
2320                DeprecatedKeyInfo keyInfo =
2321                    deprecations.getDeprecatedKeyMap().get(attr);
2322                keyInfo.clearAccessed();
2323                for (String key:keyInfo.newKeys) {
2324                  // update new keys with deprecated key's value 
2325                  loadProperty(toAddTo, name, key, value, finalParameter, 
2326                      source.toArray(new String[source.size()]));
2327                }
2328              }
2329              else {
2330                loadProperty(toAddTo, name, attr, value, finalParameter, 
2331                    source.toArray(new String[source.size()]));
2332              }
2333            }
2334          }
2335          
2336          if (returnCachedProperties) {
2337            overlay(properties, toAddTo);
2338            return new Resource(toAddTo, name);
2339          }
2340          return null;
2341        } catch (IOException e) {
2342          LOG.fatal("error parsing conf " + name, e);
2343          throw new RuntimeException(e);
2344        } catch (DOMException e) {
2345          LOG.fatal("error parsing conf " + name, e);
2346          throw new RuntimeException(e);
2347        } catch (SAXException e) {
2348          LOG.fatal("error parsing conf " + name, e);
2349          throw new RuntimeException(e);
2350        } catch (ParserConfigurationException e) {
2351          LOG.fatal("error parsing conf " + name , e);
2352          throw new RuntimeException(e);
2353        }
2354      }
2355    
2356      private void overlay(Properties to, Properties from) {
2357        for (Entry<Object, Object> entry: from.entrySet()) {
2358          to.put(entry.getKey(), entry.getValue());
2359        }
2360      }
2361      
2362      private void loadProperty(Properties properties, String name, String attr,
2363          String value, boolean finalParameter, String[] source) {
2364        if (value != null) {
2365          if (!finalParameters.contains(attr)) {
2366            properties.setProperty(attr, value);
2367            updatingResource.put(attr, source);
2368          } else {
2369            LOG.warn(name+":an attempt to override final parameter: "+attr
2370                +";  Ignoring.");
2371          }
2372        }
2373        if (finalParameter) {
2374          finalParameters.add(attr);
2375        }
2376      }
2377    
2378      /** 
2379       * Write out the non-default properties in this configuration to the given
2380       * {@link OutputStream} using UTF-8 encoding.
2381       * 
2382       * @param out the output stream to write to.
2383       */
2384      public void writeXml(OutputStream out) throws IOException {
2385        writeXml(new OutputStreamWriter(out, "UTF-8"));
2386      }
2387    
2388      /** 
2389       * Write out the non-default properties in this configuration to the given
2390       * {@link Writer}.
2391       * 
2392       * @param out the writer to write to.
2393       */
2394      public void writeXml(Writer out) throws IOException {
2395        Document doc = asXmlDocument();
2396    
2397        try {
2398          DOMSource source = new DOMSource(doc);
2399          StreamResult result = new StreamResult(out);
2400          TransformerFactory transFactory = TransformerFactory.newInstance();
2401          Transformer transformer = transFactory.newTransformer();
2402    
2403          // Important to not hold Configuration log while writing result, since
2404          // 'out' may be an HDFS stream which needs to lock this configuration
2405          // from another thread.
2406          transformer.transform(source, result);
2407        } catch (TransformerException te) {
2408          throw new IOException(te);
2409        }
2410      }
2411    
2412      /**
2413       * Return the XML DOM corresponding to this Configuration.
2414       */
2415      private synchronized Document asXmlDocument() throws IOException {
2416        Document doc;
2417        try {
2418          doc =
2419            DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
2420        } catch (ParserConfigurationException pe) {
2421          throw new IOException(pe);
2422        }
2423        Element conf = doc.createElement("configuration");
2424        doc.appendChild(conf);
2425        conf.appendChild(doc.createTextNode("\n"));
2426        handleDeprecation(); //ensure properties is set and deprecation is handled
2427        for (Enumeration<Object> e = properties.keys(); e.hasMoreElements();) {
2428          String name = (String)e.nextElement();
2429          Object object = properties.get(name);
2430          String value = null;
2431          if (object instanceof String) {
2432            value = (String) object;
2433          }else {
2434            continue;
2435          }
2436          Element propNode = doc.createElement("property");
2437          conf.appendChild(propNode);
2438    
2439          Element nameNode = doc.createElement("name");
2440          nameNode.appendChild(doc.createTextNode(name));
2441          propNode.appendChild(nameNode);
2442    
2443          Element valueNode = doc.createElement("value");
2444          valueNode.appendChild(doc.createTextNode(value));
2445          propNode.appendChild(valueNode);
2446    
2447          if (updatingResource != null) {
2448            String[] sources = updatingResource.get(name);
2449            if(sources != null) {
2450              for(String s : sources) {
2451                Element sourceNode = doc.createElement("source");
2452                sourceNode.appendChild(doc.createTextNode(s));
2453                propNode.appendChild(sourceNode);
2454              }
2455            }
2456          }
2457          
2458          conf.appendChild(doc.createTextNode("\n"));
2459        }
2460        return doc;
2461      }
2462    
2463      /**
2464       *  Writes out all the parameters and their properties (final and resource) to
2465       *  the given {@link Writer}
2466       *  The format of the output would be 
2467       *  { "properties" : [ {key1,value1,key1.isFinal,key1.resource}, {key2,value2,
2468       *  key2.isFinal,key2.resource}... ] } 
2469       *  It does not output the parameters of the configuration object which is 
2470       *  loaded from an input stream.
2471       * @param out the Writer to write to
2472       * @throws IOException
2473       */
2474      public static void dumpConfiguration(Configuration config,
2475          Writer out) throws IOException {
2476        JsonFactory dumpFactory = new JsonFactory();
2477        JsonGenerator dumpGenerator = dumpFactory.createJsonGenerator(out);
2478        dumpGenerator.writeStartObject();
2479        dumpGenerator.writeFieldName("properties");
2480        dumpGenerator.writeStartArray();
2481        dumpGenerator.flush();
2482        synchronized (config) {
2483          for (Map.Entry<Object,Object> item: config.getProps().entrySet()) {
2484            dumpGenerator.writeStartObject();
2485            dumpGenerator.writeStringField("key", (String) item.getKey());
2486            dumpGenerator.writeStringField("value", 
2487                                           config.get((String) item.getKey()));
2488            dumpGenerator.writeBooleanField("isFinal",
2489                                            config.finalParameters.contains(item.getKey()));
2490            String[] resources = config.updatingResource.get(item.getKey());
2491            String resource = UNKNOWN_RESOURCE;
2492            if(resources != null && resources.length > 0) {
2493              resource = resources[0];
2494            }
2495            dumpGenerator.writeStringField("resource", resource);
2496            dumpGenerator.writeEndObject();
2497          }
2498        }
2499        dumpGenerator.writeEndArray();
2500        dumpGenerator.writeEndObject();
2501        dumpGenerator.flush();
2502      }
2503      
2504      /**
2505       * Get the {@link ClassLoader} for this job.
2506       * 
2507       * @return the correct class loader.
2508       */
2509      public ClassLoader getClassLoader() {
2510        return classLoader;
2511      }
2512      
2513      /**
2514       * Set the class loader that will be used to load the various objects.
2515       * 
2516       * @param classLoader the new class loader.
2517       */
2518      public void setClassLoader(ClassLoader classLoader) {
2519        this.classLoader = classLoader;
2520      }
2521      
2522      @Override
2523      public String toString() {
2524        StringBuilder sb = new StringBuilder();
2525        sb.append("Configuration: ");
2526        if(loadDefaults) {
2527          toString(defaultResources, sb);
2528          if(resources.size()>0) {
2529            sb.append(", ");
2530          }
2531        }
2532        toString(resources, sb);
2533        return sb.toString();
2534      }
2535      
2536      private <T> void toString(List<T> resources, StringBuilder sb) {
2537        ListIterator<T> i = resources.listIterator();
2538        while (i.hasNext()) {
2539          if (i.nextIndex() != 0) {
2540            sb.append(", ");
2541          }
2542          sb.append(i.next());
2543        }
2544      }
2545    
2546      /** 
2547       * Set the quietness-mode. 
2548       * 
2549       * In the quiet-mode, error and informational messages might not be logged.
2550       * 
2551       * @param quietmode <code>true</code> to set quiet-mode on, <code>false</code>
2552       *              to turn it off.
2553       */
2554      public synchronized void setQuietMode(boolean quietmode) {
2555        this.quietmode = quietmode;
2556      }
2557    
2558      synchronized boolean getQuietMode() {
2559        return this.quietmode;
2560      }
2561      
2562      /** For debugging.  List non-default properties to the terminal and exit. */
2563      public static void main(String[] args) throws Exception {
2564        new Configuration().writeXml(System.out);
2565      }
2566    
2567      @Override
2568      public void readFields(DataInput in) throws IOException {
2569        clear();
2570        int size = WritableUtils.readVInt(in);
2571        for(int i=0; i < size; ++i) {
2572          String key = org.apache.hadoop.io.Text.readString(in);
2573          String value = org.apache.hadoop.io.Text.readString(in);
2574          set(key, value); 
2575          String sources[] = WritableUtils.readCompressedStringArray(in);
2576          updatingResource.put(key, sources);
2577        }
2578      }
2579    
2580      //@Override
2581      @Override
2582      public void write(DataOutput out) throws IOException {
2583        Properties props = getProps();
2584        WritableUtils.writeVInt(out, props.size());
2585        for(Map.Entry<Object, Object> item: props.entrySet()) {
2586          org.apache.hadoop.io.Text.writeString(out, (String) item.getKey());
2587          org.apache.hadoop.io.Text.writeString(out, (String) item.getValue());
2588          WritableUtils.writeCompressedStringArray(out, 
2589              updatingResource.get(item.getKey()));
2590        }
2591      }
2592      
2593      /**
2594       * get keys matching the the regex 
2595       * @param regex
2596       * @return Map<String,String> with matching keys
2597       */
2598      public Map<String,String> getValByRegex(String regex) {
2599        Pattern p = Pattern.compile(regex);
2600    
2601        Map<String,String> result = new HashMap<String,String>();
2602        Matcher m;
2603    
2604        for(Map.Entry<Object,Object> item: getProps().entrySet()) {
2605          if (item.getKey() instanceof String && 
2606              item.getValue() instanceof String) {
2607            m = p.matcher((String)item.getKey());
2608            if(m.find()) { // match
2609              result.put((String) item.getKey(), (String) item.getValue());
2610            }
2611          }
2612        }
2613        return result;
2614      }
2615    
2616      /**
2617       * A unique class which is used as a sentinel value in the caching
2618       * for getClassByName. {@see Configuration#getClassByNameOrNull(String)}
2619       */
2620      private static abstract class NegativeCacheSentinel {}
2621    
2622      public static void dumpDeprecatedKeys() {
2623        DeprecationContext deprecations = deprecationContext.get();
2624        for (Map.Entry<String, DeprecatedKeyInfo> entry :
2625            deprecations.getDeprecatedKeyMap().entrySet()) {
2626          StringBuilder newKeys = new StringBuilder();
2627          for (String newKey : entry.getValue().newKeys) {
2628            newKeys.append(newKey).append("\t");
2629          }
2630          System.out.println(entry.getKey() + "\t" + newKeys.toString());
2631        }
2632      }
2633    
2634      /**
2635       * Returns whether or not a deprecated name has been warned. If the name is not
2636       * deprecated then always return false
2637       */
2638      public static boolean hasWarnedDeprecation(String name) {
2639        DeprecationContext deprecations = deprecationContext.get();
2640        if(deprecations.getDeprecatedKeyMap().containsKey(name)) {
2641          if(deprecations.getDeprecatedKeyMap().get(name).accessed.get()) {
2642            return true;
2643          }
2644        }
2645        return false;
2646      }
2647    }