org.opends.server.core

Class LockFileManager

java.lang.Object

org.opends.server.core.LockFileManager

public final class LockFileManager
extends Object

This class provides a mechanism for allowing the Directory Server to utilize file locks as provided by the underlying OS. File locks may be exclusive or shared, and will be visible between different processes on the same system.

Method Summary

Modifier and Type	Method and Description
static boolean	acquireExclusiveLock(String lockFile, StringBuilder failureReason) Attempts to acquire an exclusive lock on the specified file.
static boolean	acquireSharedLock(String lockFile, StringBuilder failureReason) Attempts to acquire a shared lock on the specified file.
static String	getBackendLockFileName(Backend<?> backend) Retrieves the filename that should be used for the lock file for the specified backend.
static String	getServerLockFileName() Retrieves the filename that should be used for the lock file for the Directory Server instance.
static boolean	releaseLock(String lockFile, StringBuilder failureReason) Attempts to release the lock on the specified file.

Methods inherited from class java.lang.Object

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

Method Detail

acquireSharedLock

public static boolean acquireSharedLock(String lockFile,
                                        StringBuilder failureReason)

Attempts to acquire a shared lock on the specified file.

Parameters:

lockFile - The file for which to obtain the shared lock.

failureReason - A buffer that can be used to hold a reason that the lock could not be acquired.

Returns:

true if the lock was obtained successfully, or false if it could not be obtained.

acquireExclusiveLock

public static boolean acquireExclusiveLock(String lockFile,
                                           StringBuilder failureReason)

Attempts to acquire an exclusive lock on the specified file.

Parameters:

lockFile - The file for which to obtain the exclusive lock.

failureReason - A buffer that can be used to hold a reason that the lock could not be acquired.

Returns:

true if the lock was obtained successfully, or false if it could not be obtained.

releaseLock

public static boolean releaseLock(String lockFile,
                                  StringBuilder failureReason)

Attempts to release the lock on the specified file. If an exclusive lock is held, then it will be released. If a shared lock is held, then its reference count will be reduced, and the lock will be released if the resulting reference count is zero. If we don't know anything about the requested file, then don't do anything.

Parameters:

lockFile - The file for which to release the associated lock.

failureReason - A buffer that can be used to hold information about a problem that occurred preventing the successful release.

Returns:

true if the lock was found and released successfully, or false if a problem occurred that might have prevented the lock from being released.

getServerLockFileName

public static String getServerLockFileName()

Retrieves the filename that should be used for the lock file for the Directory Server instance.

Returns:

The filename that should be used for the lock file for the Directory Server instance.

getBackendLockFileName

public static String getBackendLockFileName(Backend<?> backend)

Retrieves the filename that should be used for the lock file for the specified backend.

Parameters:

backend - The backend for which to retrieve the filename for the lock file.

Returns:

The filename that should be used for the lock file for the specified backend.