util/concurrent/FairReentrantLock.java

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain. Use, modify, and
 * redistribute this code in any way without acknowledgement.
 */

package java.util.concurrent;

/**
 * A reentrant mutual exclusion lock that, under contention, favors
 * granting access to the longest-waiting thread.  Programs using fair
 * locks may display lower overall throughput (i.e., are slower) than
 * those using default locks, but have but smaller variances in times
 * to obtain locks.
 * @since 1.5
 * @author Doug Lea
 */

public class FairReentrantLock extends ReentrantLock {
    /**
     * Creates an instance of <tt>FairReentrantLock</tt>.
     */
    public FairReentrantLock() { }

    /**
     * Return true if it is OK to take fast path to lock.  For fair
     * locks, we allow barging only when there are no waiters.
     * @return true if queue empty
     */
    boolean canBarge() {
        return queueEmpty();
    }
}


Revision:	1.2
Committed:	Tue Jun 24 14:34:48 2003 UTC (20 years, 11 months ago) by dl
Branch:	MAIN
Changes since 1.1:	+3 -0 lines
Log Message:	Added missing javadoc tags; minor reformatting
#	User	Rev	Content
1	dl	1.1	/*
2			* Written by Doug Lea with assistance from members of JCP JSR-166
3			* Expert Group and released to the public domain. Use, modify, and
4			* redistribute this code in any way without acknowledgement.
5			*/
6
7			package java.util.concurrent;
8
9			/**
10			* A reentrant mutual exclusion lock that, under contention, favors
11			* granting access to the longest-waiting thread. Programs using fair
12			* locks may display lower overall throughput (i.e., are slower) than
13			* those using default locks, but have but smaller variances in times
14			* to obtain locks.
15	dl	1.2	* @since 1.5
16			* @author Doug Lea
17	dl	1.1	*/
18
19			public class FairReentrantLock extends ReentrantLock {
20			/**
21			* Creates an instance of <tt>FairReentrantLock</tt>.
22			*/
23			public FairReentrantLock() { }
24
25			/**
26			* Return true if it is OK to take fast path to lock. For fair
27			* locks, we allow barging only when there are no waiters.
28	dl	1.2	* @return true if queue empty
29	dl	1.1	*/
30			boolean canBarge() {
31			return queueEmpty();
32			}
33			}
34
35
36