Package de.aristaflow.adept2.util.locking

Class ObjectEqualityLockManager<O>

  • Type Parameters:
    O - The type of the objects to be locked being compared with Object.equals(Object).
    public class ObjectEqualityLockManager<O>
extends 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 Description
      protected ObjectLockManager<O,​Thread> olm
      The object lock manager to which all calls will be forwarded.

    • Constructor Summary

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

    • Field Detail

    • Constructor Detail

      • ObjectEqualityLockManager

        public ObjectEqualityLockManager​(String lockType,
                                 Logger logger)
                          throws 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:
        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​(String lockType,
                                 boolean optimistic,
                                 Logger logger)
                          throws 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:
        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 InterruptedException
        Locks the designated object by the current thread.
        Parameters:
        writeLock - Whether to acquire a write lock.
        lockedObject - The object to lock.
        Throws:
        InterruptedException - If the thread is interrupted while waiting for the lock, an InterruptedException will be thrown.
        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 InterruptedException,
                             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:
        InterruptedException - If the thread is interrupted while waiting for the lock, an InterruptedException will be thrown.
        TimeoutException - If the designated timeout elapsed before the lock can be acquired, a TimeoutException will be thrown.
        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.