Package 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	Description
static boolean	acquireExclusiveLock(String lockFile, StringBuilder failureReason, DirectoryEnvironmentConfig environmentConfig)	Attempts to acquire an exclusive lock on the specified file.
static void	acquireExclusiveLockForBackend(String backendID, LocalizableMessageDescriptor.Arg2<Object,Object> failureMsg, DirectoryEnvironmentConfig environmentConfig)	Attempts to acquire an exclusive lock on the specified backend ID.
static boolean	acquireSharedLock(String lockFile, StringBuilder failureReason, DirectoryEnvironmentConfig environmentConfig)	Attempts to acquire a shared lock on the specified file.
static void	acquireSharedLockForBackend(String backendID, LocalizableMessageDescriptor.Arg2<Object,Object> failureMsg, DirectoryEnvironmentConfig environmentConfig)	Attempts to acquire an shared lock on the specified backend ID.
static String	getServerLockFileName(DirectoryEnvironmentConfig environmentConfig)	Retrieves the filename that should be used for the lock file for the Directory Server instance.
static void	releaseBackendLock(String backendID, LocalizableMessageDescriptor.Arg2<Object,Object> failureMsg, DirectoryEnvironmentConfig environmentConfig)	Attempts to release a lock on the backend id.
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

acquireSharedLockForBackend

public static void acquireSharedLockForBackend(String backendID,
                                               LocalizableMessageDescriptor.Arg2<Object,Object> failureMsg,
                                               DirectoryEnvironmentConfig environmentConfig)
                                        throws LdapException

Attempts to acquire an shared lock on the specified backend ID.

Parameters:

backendID - The backend ID for which to obtain the shared lock.

failureMsg - the message to use in case the backend lock cannot be obtained.

environmentConfig - the environment config

Throws:

LdapException - if the shared lock could not be obtained.

acquireExclusiveLockForBackend

public static void acquireExclusiveLockForBackend(String backendID,
                                                  LocalizableMessageDescriptor.Arg2<Object,Object> failureMsg,
                                                  DirectoryEnvironmentConfig environmentConfig)
                                           throws LdapException

Attempts to acquire an exclusive lock on the specified backend ID.

Parameters:

backendID - The backend ID for which to obtain the exclusive lock.

failureMsg - the message to use in case the backend lock cannot be obtained.

environmentConfig - the environment config

Throws:

LdapException - if the exclusive lock could not be obtained.

acquireSharedLock

public static boolean acquireSharedLock(String lockFile,
                                        StringBuilder failureReason,
                                        DirectoryEnvironmentConfig environmentConfig)

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.

environmentConfig - The environment config

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,
                                           DirectoryEnvironmentConfig environmentConfig)

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.

environmentConfig - The environment config

Returns:

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

releaseBackendLock

public static void releaseBackendLock(String backendID,
                                      LocalizableMessageDescriptor.Arg2<Object,Object> failureMsg,
                                      DirectoryEnvironmentConfig environmentConfig)
                               throws LdapException

Attempts to release a lock on the backend id. 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:

backendID - The backend ID for which to release the associated lock.

failureMsg - the message to use in case the backe3nd lock cannot be released.

environmentConfig - the environment config

Throws:

LdapException - if a problem occurred that might have prevented the lock from being released.

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(DirectoryEnvironmentConfig environmentConfig)

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

Parameters:

environmentConfig - the environment config

Returns:

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