AbstractOwnableSynchronizer

 

/**A synchronizer that may be exclusively owned by a thread.  This
 * class provides a basis for creating locks and related synchronizers
 * that may entail a notion of ownership.  The
 * AbstractOwnableSynchronizer class itself does not manage or
 * use this information. However, subclasses and tools may use
 * appropriately maintained values to help control and monitor access
 * and provide diagnostics.
*/
public abstract class AbstractOwnableSynchronizer
    implements java.io.Serializable {

    /** Use serial ID even though all fields transient. */
    private static final long serialVersionUID = 3737899427754241961L;

    /**
     * Empty constructor for use by subclasses.
     */
    protected AbstractOwnableSynchronizer() { }

    /**
     * The current owner of exclusive mode synchronization.
     */
    private transient Thread exclusiveOwnerThread;

    /**
     * Sets the thread that currently owns exclusive access. A
     * null argument indicates that no thread owns access.
     * This method does not otherwise impose any synchronization or
     * volatile field accesses.
     */
    protected final void setExclusiveOwnerThread(Thread t) {
        exclusiveOwnerThread = t;
    }

    /**
     * Returns the thread last set by
     * setExclusiveOwnerThread, or null if never
     * set.  This method does not otherwise impose any synchronization
     * or volatile field accesses.
     * @return the owner thread
     */
    protected final Thread getExclusiveOwnerThread() {
        return exclusiveOwnerThread;
    }
}