org.apache.nutch.util
Class LockUtil

java.lang.Object
  extended by org.apache.nutch.util.LockUtil

public class LockUtil
extends Object

Utility methods for handling application-level locking.

Author:
Andrzej Bialecki

Constructor Summary
LockUtil()
           
 
Method Summary
static void createLockFile(FileSystem fs, Path lockFile, boolean accept)
          Create a lock file.
static boolean removeLockFile(FileSystem fs, Path lockFile)
          Remove lock file.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

LockUtil

public LockUtil()
Method Detail

createLockFile

public static void createLockFile(FileSystem fs,
                                  Path lockFile,
                                  boolean accept)
                           throws IOException
Create a lock file.

Parameters:
fs - filesystem
lockFile - name of the lock file
accept - if true, and the target file exists, consider it valid. If false and the target file exists, throw an IOException.
Throws:
IOException - if accept is false, and the target file already exists, or if it's a directory.

removeLockFile

public static boolean removeLockFile(FileSystem 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:
fs - filesystem
lockFile - lock file name
Returns:
false, if the lock file doesn't exist. True, if it existed and was successfully removed.
Throws:
IOException - if lock file exists but it is a directory.


Copyright © 2012 The Apache Software Foundation