Package org.apache.hadoop.hdfs.server.datanode

Class DatanodeUtil

java.lang.Object

org.apache.hadoop.hdfs.server.datanode.DatanodeUtil

@Private
public class DatanodeUtil
extends java.lang.Object

Provide utility methods for Datanode.

Field Summary

Fields

Modifier and Type	Field	Description
static java.lang.String	DISK_ERROR
static java.lang.String	UNLINK_BLOCK_SUFFIX

Constructor Summary

Constructors

Constructor	Description
DatanodeUtil()

Method Summary

Modifier and Type	Method	Description
static java.io.File	createFileWithExistsCheck(FsVolumeSpi volume, org.apache.hadoop.hdfs.protocol.Block b, java.io.File f, FileIoProvider fileIoProvider)	Create a new file.
static boolean	dirNoFilesRecursive(FsVolumeSpi volume, java.io.File dir, FileIoProvider fileIoProvider)	Checks whether there are any files anywhere in the directory tree rooted at dir (directories don't count as files).
static java.io.FileInputStream	getMetaDataInputStream(org.apache.hadoop.hdfs.protocol.ExtendedBlock b, FsDatasetSpi<?> data)
static java.lang.String	getMetaName(java.lang.String blockName, long generationStamp)
static java.io.File	getUnlinkTmpFile(java.io.File f)
static java.io.File	idToBlockDir(java.io.File root, long blockId)	Get the directory where a finalized block with this ID should be stored.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

UNLINK_BLOCK_SUFFIX

public static final java.lang.String UNLINK_BLOCK_SUFFIX

See Also:

Constant Field Values

DISK_ERROR

public static final java.lang.String DISK_ERROR

See Also:

Constant Field Values

Constructor Detail

DatanodeUtil

public DatanodeUtil()

Method Detail

createFileWithExistsCheck

public static java.io.File createFileWithExistsCheck(FsVolumeSpi volume,
                                                     org.apache.hadoop.hdfs.protocol.Block b,
                                                     java.io.File f,
                                                     FileIoProvider fileIoProvider)
                                              throws java.io.IOException

Create a new file.

Throws:

java.io.IOException - if the file already exists or if the file cannot be created.

getMetaName

public static java.lang.String getMetaName(java.lang.String blockName,
                                           long generationStamp)

Returns:

the meta name given the block name and generation stamp.

getUnlinkTmpFile

public static java.io.File getUnlinkTmpFile(java.io.File f)

Returns:

the unlink file.

dirNoFilesRecursive

public static boolean dirNoFilesRecursive(FsVolumeSpi volume,
                                          java.io.File dir,
                                          FileIoProvider fileIoProvider)
                                   throws java.io.IOException

Checks whether there are any files anywhere in the directory tree rooted at dir (directories don't count as files). dir must exist

Returns:

true if there are no files

Throws:

java.io.IOException - if unable to list subdirectories

idToBlockDir

public static java.io.File idToBlockDir(java.io.File root,
                                        long blockId)

Get the directory where a finalized block with this ID should be stored. Do not attempt to create the directory.

Parameters:

root - the root directory where finalized blocks are stored

blockId -

Returns:

getMetaDataInputStream

public static java.io.FileInputStream getMetaDataInputStream(org.apache.hadoop.hdfs.protocol.ExtendedBlock b,
                                                             FsDatasetSpi<?> data)
                                                      throws java.io.IOException

Returns:

the FileInputStream for the meta data of the given block.

Throws:

java.io.FileNotFoundException - if the file not found.

java.lang.ClassCastException - if the underlying input stream is not a FileInputStream.

java.io.IOException