test/loops/ReadHoldingWriteLock.java

import java.util.concurrent.locks.*;

class ReadHoldingWriteLock {

    public static void main(String[] args) throws Exception {
        ReadHoldingWriteLock t = new ReadHoldingWriteLock();
        t.testReadAfterWriteLock();
        t.testReadHoldingWriteLock();
        t.testReadHoldingWriteLock2();
        t.testReadHoldingWriteLockFair();
        t.testReadHoldingWriteLockFair2();
    }

    static final long SHORT_DELAY_MS = 50;
    static final long MEDIUM_DELAY_MS = 200;

    void assertTrue(boolean b) {
        if (!b) throw new Error();
    }

    /**
     * Readlocks succeed after a writing thread unlocks
     */
    public void testReadAfterWriteLock() throws Exception { 
        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
        lock.writeLock().lock();
        Thread t1 = new Thread(new Runnable() {
                public void run() {
                    lock.readLock().lock();
                    lock.readLock().unlock();
                }
            });
        Thread t2 = new Thread(new Runnable() {
                public void run() {
                    lock.readLock().lock();
                    lock.readLock().unlock();
                }
            });

        t1.start();
        t2.start();
        Thread.sleep(SHORT_DELAY_MS);
        lock.writeLock().unlock();
        t1.join(MEDIUM_DELAY_MS);
        t2.join(MEDIUM_DELAY_MS);
        assertTrue(!t1.isAlive());
        assertTrue(!t2.isAlive());
        
    } 

    /**
     * Read trylock succeeds if write locked by current thread
     */
    public void testReadHoldingWriteLock()throws Exception { 
        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
        lock.writeLock().lock();
        assertTrue(lock.readLock().tryLock());
        lock.readLock().unlock();
        lock.writeLock().unlock();
    } 

    /**
     * Read lock succeeds if write locked by current thread even if
     * other threads are waiting
     */
    public void testReadHoldingWriteLock2() throws Exception{ 
        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
        lock.writeLock().lock();
        Thread t1 = new Thread(new Runnable() {
                public void run() {
                    lock.readLock().lock();
                    lock.readLock().unlock();
                }
            });
        Thread t2 = new Thread(new Runnable() {
                public void run() {
                    lock.readLock().lock();
                    lock.readLock().unlock();
                }
            });
        
        t1.start();
        t2.start();
        lock.readLock().lock();
        lock.readLock().unlock();
        Thread.sleep(SHORT_DELAY_MS);
        lock.readLock().lock();
        lock.readLock().unlock();
        lock.writeLock().unlock();
        t1.join(MEDIUM_DELAY_MS);
        t2.join(MEDIUM_DELAY_MS);
        assertTrue(!t1.isAlive());
        assertTrue(!t2.isAlive());
    } 

    /**
     * Fair Read trylock succeeds if write locked by current thread
     */
    public void testReadHoldingWriteLockFair() throws Exception{ 
        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
        lock.writeLock().lock();
        assertTrue(lock.readLock().tryLock());
        lock.readLock().unlock();
        lock.writeLock().unlock();
    } 

    /**
     * Fair Read lock succeeds if write locked by current thread even if
     * other threads are waiting
     */
    public void testReadHoldingWriteLockFair2() throws Exception { 
        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
        lock.writeLock().lock();
        Thread t1 = new Thread(new Runnable() {
                public void run() {
                    lock.readLock().lock();
                    lock.readLock().unlock();
                }
            });
        Thread t2 = new Thread(new Runnable() {
                public void run() {
                    lock.readLock().lock();
                    lock.readLock().unlock();
                }
            });

        t1.start();
        t2.start();
        lock.readLock().lock();
        lock.readLock().unlock();
        Thread.sleep(SHORT_DELAY_MS);
        lock.readLock().lock();
        lock.readLock().unlock();
        lock.writeLock().unlock();
        t1.join(MEDIUM_DELAY_MS);
        t2.join(MEDIUM_DELAY_MS);
        assertTrue(!t1.isAlive());
        assertTrue(!t2.isAlive());
        

    } 
}
Revision:	1.1
Committed:	Mon May 2 19:19:38 2005 UTC (19 years ago) by dl
Branch:	MAIN
Log Message:	Put misc performance tests into CVS
#	User	Rev	Content
1	dl	1.1	import java.util.concurrent.locks.*;
2
3			class ReadHoldingWriteLock {
4
5			public static void main(String[] args) throws Exception {
6			ReadHoldingWriteLock t = new ReadHoldingWriteLock();
7			t.testReadAfterWriteLock();
8			t.testReadHoldingWriteLock();
9			t.testReadHoldingWriteLock2();
10			t.testReadHoldingWriteLockFair();
11			t.testReadHoldingWriteLockFair2();
12			}
13
14			static final long SHORT_DELAY_MS = 50;
15			static final long MEDIUM_DELAY_MS = 200;
16
17			void assertTrue(boolean b) {
18			if (!b) throw new Error();
19			}
20
21			/**
22			* Readlocks succeed after a writing thread unlocks
23			*/
24			public void testReadAfterWriteLock() throws Exception {
25			final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
26			lock.writeLock().lock();
27			Thread t1 = new Thread(new Runnable() {
28			public void run() {
29			lock.readLock().lock();
30			lock.readLock().unlock();
31			}
32			});
33			Thread t2 = new Thread(new Runnable() {
34			public void run() {
35			lock.readLock().lock();
36			lock.readLock().unlock();
37			}
38			});
39
40			t1.start();
41			t2.start();
42			Thread.sleep(SHORT_DELAY_MS);
43			lock.writeLock().unlock();
44			t1.join(MEDIUM_DELAY_MS);
45			t2.join(MEDIUM_DELAY_MS);
46			assertTrue(!t1.isAlive());
47			assertTrue(!t2.isAlive());
48
49			}
50
51			/**
52			* Read trylock succeeds if write locked by current thread
53			*/
54			public void testReadHoldingWriteLock()throws Exception {
55			final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
56			lock.writeLock().lock();
57			assertTrue(lock.readLock().tryLock());
58			lock.readLock().unlock();
59			lock.writeLock().unlock();
60			}
61
62			/**
63			* Read lock succeeds if write locked by current thread even if
64			* other threads are waiting
65			*/
66			public void testReadHoldingWriteLock2() throws Exception{
67			final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
68			lock.writeLock().lock();
69			Thread t1 = new Thread(new Runnable() {
70			public void run() {
71			lock.readLock().lock();
72			lock.readLock().unlock();
73			}
74			});
75			Thread t2 = new Thread(new Runnable() {
76			public void run() {
77			lock.readLock().lock();
78			lock.readLock().unlock();
79			}
80			});
81
82			t1.start();
83			t2.start();
84			lock.readLock().lock();
85			lock.readLock().unlock();
86			Thread.sleep(SHORT_DELAY_MS);
87			lock.readLock().lock();
88			lock.readLock().unlock();
89			lock.writeLock().unlock();
90			t1.join(MEDIUM_DELAY_MS);
91			t2.join(MEDIUM_DELAY_MS);
92			assertTrue(!t1.isAlive());
93			assertTrue(!t2.isAlive());
94			}
95
96			/**
97			* Fair Read trylock succeeds if write locked by current thread
98			*/
99			public void testReadHoldingWriteLockFair() throws Exception{
100			final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
101			lock.writeLock().lock();
102			assertTrue(lock.readLock().tryLock());
103			lock.readLock().unlock();
104			lock.writeLock().unlock();
105			}
106
107			/**
108			* Fair Read lock succeeds if write locked by current thread even if
109			* other threads are waiting
110			*/
111			public void testReadHoldingWriteLockFair2() throws Exception {
112			final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
113			lock.writeLock().lock();
114			Thread t1 = new Thread(new Runnable() {
115			public void run() {
116			lock.readLock().lock();
117			lock.readLock().unlock();
118			}
119			});
120			Thread t2 = new Thread(new Runnable() {
121			public void run() {
122			lock.readLock().lock();
123			lock.readLock().unlock();
124			}
125			});
126
127			t1.start();
128			t2.start();
129			lock.readLock().lock();
130			lock.readLock().unlock();
131			Thread.sleep(SHORT_DELAY_MS);
132			lock.readLock().lock();
133			lock.readLock().unlock();
134			lock.writeLock().unlock();
135			t1.join(MEDIUM_DELAY_MS);
136			t2.join(MEDIUM_DELAY_MS);
137			assertTrue(!t1.isAlive());
138			assertTrue(!t2.isAlive());
139
140
141			}
142			}