org.exist.storage.lock
Interface Lock

All Known Implementing Classes:

MultiReadReentrantLock, ReentrantReadWriteLock

public interface Lock

Field Summary

static int	NO_LOCK
static int	READ_LOCK
static int	WRITE_LOCK

Method Summary

boolean	acquire() Acquire a lock for read.
boolean	acquire(int mode) Acquire a lock for read or write.
boolean	attempt(int mode) Attempt to acquire a lock for read or write.
String	getId()
LockInfo	getLockInfo() Create a LockInfo entry for the given lock.
boolean	hasLock() Check if the lock is currently locked by someone.
boolean	hasLock(Thread owner) Check if the specified thread holds either a write or a read lock on the resource.
boolean	isLockedForRead(Thread owner) Check if the specified thread does currently hold a read lock.
boolean	isLockedForWrite() Returns true if there are active or pending write locks.
void	release(int mode) Release a lock of the specified type.
void	release(int mode, int count)
void	wakeUp() Wake up waiting threads and recompute dependencies.

Field Detail

READ_LOCK

static final int READ_LOCK

See Also:

Constant Field Values

WRITE_LOCK

static final int WRITE_LOCK

See Also:

Constant Field Values

NO_LOCK

static final int NO_LOCK

See Also:

Constant Field Values

Method Detail

acquire

boolean acquire()
                throws LockException

Acquire a lock for read.

Throws:

LockException

acquire

boolean acquire(int mode)
                throws LockException

Acquire a lock for read or write. mode is one of READ_LOCK or WRITE_LOCK.

Parameters:

mode -

Throws:

LockException

attempt

boolean attempt(int mode)

Attempt to acquire a lock for read or write. This method will fail immediately if the lock cannot be acquired.

Parameters:

mode -

release

void release(int mode)

Release a lock of the specified type.

Parameters:

mode -

release

void release(int mode,
             int count)

isLockedForWrite

boolean isLockedForWrite()

Returns true if there are active or pending write locks.

isLockedForRead

boolean isLockedForRead(Thread owner)

Check if the specified thread does currently hold a read lock.

Parameters:

owner - the thread to search for

Returns:

true if the thread holds a read lock

hasLock

boolean hasLock()

Check if the lock is currently locked by someone.

Returns:

true if there's an active read or write lock

hasLock

boolean hasLock(Thread owner)

Check if the specified thread holds either a write or a read lock on the resource.

Parameters:

owner - the thread

Returns:

true if owner has a lock

wakeUp

void wakeUp()

Wake up waiting threads and recompute dependencies. Currently used to rerun deadlock detection.

getId

String getId()

getLockInfo

LockInfo getLockInfo()

Create a LockInfo entry for the given lock.

Returns:

the lock info