de.aristaflow.adept2.util.locking

Class ObjectEqualityLockManager<O>

java.lang.Object

de.aristaflow.adept2.util.locking.ObjectEqualityLockManager<O>

Type Parameters:

O - The type of the objects to be locked being compared with Object.equals(Object).

public class ObjectEqualityLockManager<O>
extends java.lang.Object

Class with convenience methods for an ObjectLockManager using the current thread for locking and using object equality for the locked objects.

Author:

Ulrich Kreher

Field Summary

Fields

Modifier and Type	Field and Description
protected ObjectLockManager<O,java.lang.Thread>	olm The object lock manager to which all calls will be forwarded.

Constructor Summary

Constructors

Constructor and Description
ObjectEqualityLockManager(java.lang.String lockType, boolean optimistic, java.util.logging.Logger logger) Creates a new ObjectLockManager using the current thread for locking and using object equality for the locked objects.
ObjectEqualityLockManager(java.lang.String lockType, java.util.logging.Logger logger) Creates a new ObjectLockManager with pessimistic locking using the current thread for locking and using object equality for the locked objects.

Method Summary

Modifier and Type	Method and Description
void	getLockForObject(boolean writeLock, O lockedObject) Locks the designated object by the current thread.
void	getLockForObject(boolean writeLock, O lockedObject, long timeout) Locks the designated object by the current thread.
boolean	hasLock(boolean writeLock, O lockedObject) Checks whether the designated object is locked for reading or writing by the current thread.
void	unlockObject(boolean writeLock, O lockedObject) Unlocks the designated object by the current thread.

Methods inherited from class java.lang.Object

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

Field Detail

olm

protected final ObjectLockManager<O,java.lang.Thread> olm

The object lock manager to which all calls will be forwarded.

Constructor Detail

ObjectEqualityLockManager

public ObjectEqualityLockManager(java.lang.String lockType,
                                 java.util.logging.Logger logger)
                          throws java.lang.reflect.InvocationTargetException

Creates a new ObjectLockManager with pessimistic locking using the current thread for locking and using object equality for the locked objects.

Parameters:

lockType - The type of locks managed by the created object. This is for user information only.

logger - The logger for log messages.

Throws:

java.lang.reflect.InvocationTargetException - If there are problems instantiating the lock count manager or the reentrant lock, an InvocationTargetException will be thrown. This prevents problems at runtime when actually retrieving a lock (which requires creating the corresponding objects).

ObjectEqualityLockManager

public ObjectEqualityLockManager(java.lang.String lockType,
                                 boolean optimistic,
                                 java.util.logging.Logger logger)
                          throws java.lang.reflect.InvocationTargetException

Creates a new ObjectLockManager using the current thread for locking and using object equality for the locked objects.

Parameters:

lockType - The type of locks managed by the created object. This is for user information only.

optimistic - Whether to use optimistic locking which prevents synchronisation but may create unneeded objects. This is suggested with not much lock contention.

logger - The logger for log messages.

Throws:

java.lang.reflect.InvocationTargetException - If there are problems instantiating the lock count manager or the reentrant lock, an InvocationTargetException will be thrown. This prevents problems at runtime when actually retrieving a lock (which requires creating the corresponding objects).

Method Detail

getLockForObject

public void getLockForObject(boolean writeLock,
                             O lockedObject)
                      throws java.lang.InterruptedException

Locks the designated object by the current thread.

Parameters:

writeLock - Whether to acquire a write lock.

lockedObject - The object to lock.

Throws:

java.lang.InterruptedException - If the thread is interrupted while waiting for the lock, an InterruptedException will be thrown.

java.lang.RuntimeException - If the provided lock count manager can not be instantiated, a RuntimeException will be thrown.

getLockForObject

public void getLockForObject(boolean writeLock,
                             O lockedObject,
                             long timeout)
                      throws java.lang.InterruptedException,
                             java.util.concurrent.TimeoutException

Locks the designated object by the current thread. Since the locks are expected to be short-term this method will wait until the lock can be successfully acquired. The locks are reentrant, that is, it needs to be unlocked for every call to this method and for the right lock type (read or write lock).

Parameters:

writeLock - Whether to acquire a write lock.

lockedObject - The object to lock.

timeout - The time to wait for the lock. A timeout <= 0 means to wait forever (or until the lock is granted).

Throws:

java.lang.InterruptedException - If the thread is interrupted while waiting for the lock, an InterruptedException will be thrown.

java.util.concurrent.TimeoutException - If the designated timeout elapsed before the lock can be acquired, a TimeoutException will be thrown.

java.lang.RuntimeException - If the provided lock or the lock count manager can not be instantiated, a RuntimeException will be thrown.

hasLock

public boolean hasLock(boolean writeLock,
                       O lockedObject)

Checks whether the designated object is locked for reading or writing by the current thread.

Parameters:

writeLock - Whether the locking object is to be checked for having a write lock on the designated locked object.

lockedObject - The object to check for the lock lock.

Returns:

Whether the designated locking object has the designated lock on the designated locked object.

unlockObject

public void unlockObject(boolean writeLock,
                         O lockedObject)
                  throws LockException

Unlocks the designated object by the current thread. The lock will not be released if it is held several times. If an exception occurs while trying to unlock, the lock will still be held when returning.

Parameters:

writeLock - Whether to release the write lock.

lockedObject - The object to unlock.

Throws:

LockException - If the locked object has not locked at all or not by the designated locking object, a LockException will be thrown.