Package org.apache.hadoop.hdfs.util

Interface Summary

Interface	Description
Diff.Element<K>	An interface for the elements in a Diff.
Diff.Processor<E>	An interface for passing a method in order to process elements.
ReadOnlyList<E>	A ReadOnlyList is a unmodifiable list, which supports read-only operations.
ReferenceCountMap.ReferenceCounter	Interface for the reference count holder
RwLock	Read-write lock interface.

Class Summary

Class	Description
AsyncRFAAppender	Until we migrate to log4j2, use this appender for namenode audit logger as well as datanode and namenode metric loggers with log4j properties, if async logging is required with RFA.
AtomicFileOutputStream	A FileOutputStream that has the property that it will only show up at its destination once it has been entirely written and flushed to disk.
BestEffortLongFile	Class that represents a file on disk which stores a single long value, but does not make any effort to make it truly durable.
ByteArray	Wrapper for byte[] to use byte[] as key in HashMap
Canceler	Provides a simple interface where one thread can mark an operation for cancellation, and another thread can poll for whether the cancellation has occurred.
ConstEnumCounters<E extends java.lang.Enum<E>>	Const Counters for an enum type.
CyclicIteration<K,V>	Provide an cyclic Iterator for a NavigableMap.
DataTransferThrottler	a class to throttle the data transfers.
Diff<K,E extends Diff.Element<K>>	The difference between the current state and a previous state of a list.
Diff.Container<E>	Containing exactly one element.
Diff.UndoInfo<E>	Undo information for some operations such as delete(E) and Diff.modify(Element, Element).
EnumCounters<E extends java.lang.Enum<E>>	Counters for an enum type.
EnumDoubles<E extends java.lang.Enum<E>>	Similar to EnumCounters except that the value type is double.
Holder<T>	A Holder is simply a wrapper around some other object.
LightWeightHashSet<T>	A low memory linked hash set implementation, which uses an array for storing the elements and linked lists for collision resolution.
LightWeightLinkedSet<T>	A low memory linked hash set implementation, which uses an array for storing the elements and linked lists for collision resolution.
MD5FileUtils	Static functions for dealing with files of the same format that the Unix "md5sum" utility writes.
PersistentLongFile	Class that represents a file on disk which persistently stores a single long value.
ReadOnlyList.Util	Utilities for ReadOnlyList
ReferenceCountMap<E extends ReferenceCountMap.ReferenceCounter>	Class for de-duplication of instances.
XMLUtils	General xml utilities.
XMLUtils.Stanza	Represents a bag of key-value pairs encountered during parsing an XML file.

Exception Summary

Exception	Description
ConstEnumCounters.ConstEnumException	An exception class for modification on ConstEnumCounters.
XMLUtils.InvalidXmlException	Exception that reflects an invalid XML document.
XMLUtils.UnmanglingError	Exception that reflects a string that cannot be unmangled.