[TOC]

org.apache.nutch.util

Class LockUtil

public class LockUtil
extends Object

Utility methods for handling application-level locking.

  • Author:
  • Andrzej Bialecki

Constructor Summary

Constructors Constructor and Description LockUtil()

Method Summary

Methods Modifier and Type Method and Description static void createLockFile(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path lockFile, boolean accept) Create a lock file. static boolean removeLockFile(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path lockFile) Remove lock file.

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Methods inherited from class java.lang.Object

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

Constructor Detail

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LockUtil

public LockUtil()

Method Detail

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createLockFile

public static void createLockFile(org.apache.hadoop.fs.FileSystem fs,
                  org.apache.hadoop.fs.Path lockFile,
                  boolean accept)
                           throws IOException

Create a lock file.

  - Parameters:
  - <code>fs</code> - filesystem
  - <code>lockFile</code> - name of the lock file
  - <code>accept</code> - if true, and the target file exists, consider it valid. If false and the target file exists, throw an IOException. 
  - Throws: 
  - <code>IOException</code> - if accept is false, and the target file already exists, or if it&#39;s a directory.       
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removeLockFile

public static boolean removeLockFile(org.apache.hadoop.fs.FileSystem fs,
                     org.apache.hadoop.fs.Path lockFile)
                              throws IOException

Remove lock file. NOTE: applications enforce the semantics of this file - this method simply removes any file with a given name.

  - Parameters:
  - <code>fs</code> - filesystem
  - <code>lockFile</code> - lock file name 
  - Returns:
  - false, if the lock file doesn&#39;t exist. True, if it existed and was successfully removed. 
  - Throws: 
  - <code>IOException</code> - if lock file exists but it is a directory.

Copyright © 2014 The Apache Software Foundation