test/tck/AtomicLongFieldUpdaterTest.java

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 * Other contributors include Andrew Wright, Jeffrey Hayes,
 * Pat Fisher, Mike Judd.
 */

import java.util.concurrent.atomic.AtomicLongFieldUpdater;

import junit.framework.Test;
import junit.framework.TestSuite;

public class AtomicLongFieldUpdaterTest extends JSR166TestCase {
    volatile long x = 0;
    protected volatile long protectedField;
    private volatile long privateField;
    long w;
    float z;
    public static void main(String[] args) {
        main(suite(), args);
    }
    public static Test suite() {
        return new TestSuite(AtomicLongFieldUpdaterTest.class);
    }

    // for testing subclass access
    static class AtomicLongFieldUpdaterTestSubclass extends AtomicLongFieldUpdaterTest {
        public void checkPrivateAccess() {
            try {
                AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a =
                    AtomicLongFieldUpdater.newUpdater
                    (AtomicLongFieldUpdaterTest.class, "privateField");
                shouldThrow();
            } catch (RuntimeException success) {
                assertNotNull(success.getCause());
            }
        }

        public void checkCompareAndSetProtectedSub() {
            AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
            a = updaterFor("protectedField");
            protectedField = 1;
            assertTrue(a.compareAndSet(this, 1, 2));
            assertTrue(a.compareAndSet(this, 2, -4));
            assertEquals(-4, a.get(this));
            assertFalse(a.compareAndSet(this, -5, 7));
            assertEquals(-4, a.get(this));
            assertTrue(a.compareAndSet(this, -4, 7));
            assertEquals(7, a.get(this));
        }
    }

    static class UnrelatedClass {
        public void checkPrivateAccess() {
            Exception ex = null;
            try {
                AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a =
                    AtomicLongFieldUpdater.newUpdater
                    (AtomicLongFieldUpdaterTest.class, "x");
            } catch (RuntimeException rex) {
                ex = rex;
            }
            if (ex != null) throw new Error();
        }
    }

    AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> updaterFor(String fieldName) {
        return AtomicLongFieldUpdater.newUpdater
            (AtomicLongFieldUpdaterTest.class, fieldName);
    }

    /**
     * Construction with non-existent field throws RuntimeException
     */
    public void testConstructor() {
        try {
            updaterFor("y");
            shouldThrow();
        } catch (RuntimeException success) {
            assertNotNull(success.getCause());
        }
    }

    /**
     * construction with field not of given type throws IllegalArgumentException
     */
    public void testConstructor2() {
        try {
            updaterFor("z");
            shouldThrow();
        } catch (IllegalArgumentException success) {}
    }

    /**
     * construction with non-volatile field throws IllegalArgumentException
     */
    public void testConstructor3() {
        try {
            updaterFor("w");
            shouldThrow();
        } catch (IllegalArgumentException success) {}
    }

    /**
     * construction using private field from subclass throws RuntimeException
     */
    public void testPrivateFieldInSubclass() {
        AtomicLongFieldUpdaterTestSubclass s =
            new AtomicLongFieldUpdaterTestSubclass();
        s.checkPrivateAccess();
    }

    /**
     * construction from unrelated class throws RuntimeException
     */
    public void testUnrelatedClassAccess() {
        UnrelatedClass s = new UnrelatedClass();
        s.checkPrivateAccess();
    }

    /**
     * get returns the last value set or assigned
     */
    public void testGetSet() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");
        x = 1;
        assertEquals(1, a.get(this));
        a.set(this, 2);
        assertEquals(2, a.get(this));
        a.set(this, -3);
        assertEquals(-3, a.get(this));
    }

    /**
     * get returns the last value lazySet by same thread
     */
    public void testGetLazySet() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");
        x = 1;
        assertEquals(1, a.get(this));
        a.lazySet(this, 2);
        assertEquals(2, a.get(this));
        a.lazySet(this, -3);
        assertEquals(-3, a.get(this));
    }

    /**
     * compareAndSet succeeds in changing value if equal to expected else fails
     */
    public void testCompareAndSet() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");
        x = 1;
        assertTrue(a.compareAndSet(this, 1, 2));
        assertTrue(a.compareAndSet(this, 2, -4));
        assertEquals(-4, a.get(this));
        assertFalse(a.compareAndSet(this, -5, 7));
        assertEquals(-4, a.get(this));
        assertTrue(a.compareAndSet(this, -4, 7));
        assertEquals(7, a.get(this));
    }

    /**
     * compareAndSet succeeds in changing protected field value if
     * equal to expected else fails
     */
    public void testCompareAndSetProtected() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("protectedField");
        protectedField = 1;
        assertTrue(a.compareAndSet(this, 1, 2));
        assertTrue(a.compareAndSet(this, 2, -4));
        assertEquals(-4, a.get(this));
        assertFalse(a.compareAndSet(this, -5, 7));
        assertEquals(-4, a.get(this));
        assertTrue(a.compareAndSet(this, -4, 7));
        assertEquals(7, a.get(this));
    }

    /**
     * compareAndSet succeeds in changing protected field value if
     * equal to expected else fails
     */
    public void testCompareAndSetProtectedInSubclass() {
        AtomicLongFieldUpdaterTestSubclass s =
            new AtomicLongFieldUpdaterTestSubclass();
        s.checkCompareAndSetProtectedSub();
    }

    /**
     * compareAndSet in one thread enables another waiting for value
     * to succeed
     */
    public void testCompareAndSetInMultipleThreads() throws Exception {
        x = 1;
        final AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");

        Thread t = new Thread(new CheckedRunnable() {
            public void realRun() {
                while (!a.compareAndSet(AtomicLongFieldUpdaterTest.this, 2, 3))
                    Thread.yield();
            }});

        t.start();
        assertTrue(a.compareAndSet(this, 1, 2));
        t.join(LONG_DELAY_MS);
        assertFalse(t.isAlive());
        assertEquals(3, a.get(this));
    }

    /**
     * repeated weakCompareAndSet succeeds in changing value when equal
     * to expected
     */
    public void testWeakCompareAndSet() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");
        x = 1;
        do {} while (!a.weakCompareAndSet(this, 1, 2));
        do {} while (!a.weakCompareAndSet(this, 2, -4));
        assertEquals(-4, a.get(this));
        do {} while (!a.weakCompareAndSet(this, -4, 7));
        assertEquals(7, a.get(this));
    }

    /**
     * getAndSet returns previous value and sets to given value
     */
    public void testGetAndSet() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");
        x = 1;
        assertEquals(1, a.getAndSet(this, 0));
        assertEquals(0, a.getAndSet(this, -10));
        assertEquals(-10, a.getAndSet(this, 1));
    }

    /**
     * getAndAdd returns previous value and adds given value
     */
    public void testGetAndAdd() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");
        x = 1;
        assertEquals(1, a.getAndAdd(this, 2));
        assertEquals(3, a.get(this));
        assertEquals(3, a.getAndAdd(this, -4));
        assertEquals(-1, a.get(this));
    }

    /**
     * getAndDecrement returns previous value and decrements
     */
    public void testGetAndDecrement() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");
        x = 1;
        assertEquals(1, a.getAndDecrement(this));
        assertEquals(0, a.getAndDecrement(this));
        assertEquals(-1, a.getAndDecrement(this));
    }

    /**
     * getAndIncrement returns previous value and increments
     */
    public void testGetAndIncrement() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");
        x = 1;
        assertEquals(1, a.getAndIncrement(this));
        assertEquals(2, a.get(this));
        a.set(this, -2);
        assertEquals(-2, a.getAndIncrement(this));
        assertEquals(-1, a.getAndIncrement(this));
        assertEquals(0, a.getAndIncrement(this));
        assertEquals(1, a.get(this));
    }

    /**
     * addAndGet adds given value to current, and returns current value
     */
    public void testAddAndGet() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");
        x = 1;
        assertEquals(3, a.addAndGet(this, 2));
        assertEquals(3, a.get(this));
        assertEquals(-1, a.addAndGet(this, -4));
        assertEquals(-1, a.get(this));
    }

    /**
     * decrementAndGet decrements and returns current value
     */
    public void testDecrementAndGet() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");
        x = 1;
        assertEquals(0, a.decrementAndGet(this));
        assertEquals(-1, a.decrementAndGet(this));
        assertEquals(-2, a.decrementAndGet(this));
        assertEquals(-2, a.get(this));
    }

    /**
     * incrementAndGet increments and returns current value
     */
    public void testIncrementAndGet() {
        AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
        a = updaterFor("x");
        x = 1;
        assertEquals(2, a.incrementAndGet(this));
        assertEquals(2, a.get(this));
        a.set(this, -2);
        assertEquals(-1, a.incrementAndGet(this));
        assertEquals(0, a.incrementAndGet(this));
        assertEquals(1, a.incrementAndGet(this));
        assertEquals(1, a.get(this));
    }

}
Revision:	1.30
Committed:	Sun Nov 8 15:34:01 2015 UTC (8 years, 6 months ago) by dl
Branch:	MAIN
Changes since 1.29:	+88 -2 lines
Log Message:	Add tests checking the forms of thrown exceptions
#	User	Rev	Content
1	dl	1.1	/*
2	dl	1.6	* Written by Doug Lea with assistance from members of JCP JSR-166
3			* Expert Group and released to the public domain, as explained at
4	jsr166	1.19	* http://creativecommons.org/publicdomain/zero/1.0/
5	jsr166	1.10	* Other contributors include Andrew Wright, Jeffrey Hayes,
6			* Pat Fisher, Mike Judd.
7	dl	1.1	*/
8
9	jsr166	1.21	import java.util.concurrent.atomic.AtomicLongFieldUpdater;
10	dl	1.1
11	jsr166	1.27	import junit.framework.Test;
12			import junit.framework.TestSuite;
13
14	dl	1.2	public class AtomicLongFieldUpdaterTest extends JSR166TestCase {
15	dl	1.1	volatile long x = 0;
16	dl	1.30	protected volatile long protectedField;
17			private volatile long privateField;
18	dl	1.4	long w;
19	dl	1.30	float z;
20	jsr166	1.12	public static void main(String[] args) {
21	jsr166	1.29	main(suite(), args);
22	dl	1.1	}
23			public static Test suite() {
24			return new TestSuite(AtomicLongFieldUpdaterTest.class);
25			}
26
27	dl	1.30	// for testing subclass access
28			static class AtomicLongFieldUpdaterTestSubclass extends AtomicLongFieldUpdaterTest {
29			public void checkPrivateAccess() {
30			try {
31			AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a =
32			AtomicLongFieldUpdater.newUpdater
33			(AtomicLongFieldUpdaterTest.class, "privateField");
34			shouldThrow();
35			} catch (RuntimeException success) {
36			assertNotNull(success.getCause());
37			}
38			}
39
40			public void checkCompareAndSetProtectedSub() {
41			AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
42			a = updaterFor("protectedField");
43			protectedField = 1;
44			assertTrue(a.compareAndSet(this, 1, 2));
45			assertTrue(a.compareAndSet(this, 2, -4));
46			assertEquals(-4, a.get(this));
47			assertFalse(a.compareAndSet(this, -5, 7));
48			assertEquals(-4, a.get(this));
49			assertTrue(a.compareAndSet(this, -4, 7));
50			assertEquals(7, a.get(this));
51			}
52			}
53
54			static class UnrelatedClass {
55			public void checkPrivateAccess() {
56			Exception ex = null;
57			try {
58			AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a =
59			AtomicLongFieldUpdater.newUpdater
60			(AtomicLongFieldUpdaterTest.class, "x");
61			} catch (RuntimeException rex) {
62			ex = rex;
63			}
64			if (ex != null) throw new Error();
65			}
66			}
67
68	jsr166	1.24	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> updaterFor(String fieldName) {
69			return AtomicLongFieldUpdater.newUpdater
70			(AtomicLongFieldUpdaterTest.class, fieldName);
71			}
72
73	dl	1.3	/**
74	dl	1.7	* Construction with non-existent field throws RuntimeException
75	dl	1.3	*/
76	jsr166	1.12	public void testConstructor() {
77	jsr166	1.11	try {
78	jsr166	1.24	updaterFor("y");
79	dl	1.3	shouldThrow();
80	jsr166	1.25	} catch (RuntimeException success) {
81	jsr166	1.26	assertNotNull(success.getCause());
82	jsr166	1.25	}
83	dl	1.1	}
84
85	dl	1.3	/**
86	jsr166	1.25	* construction with field not of given type throws IllegalArgumentException
87	dl	1.3	*/
88	jsr166	1.12	public void testConstructor2() {
89	jsr166	1.11	try {
90	jsr166	1.24	updaterFor("z");
91	dl	1.3	shouldThrow();
92	jsr166	1.25	} catch (IllegalArgumentException success) {}
93	dl	1.1	}
94
95	dl	1.3	/**
96	jsr166	1.25	* construction with non-volatile field throws IllegalArgumentException
97	dl	1.3	*/
98	jsr166	1.12	public void testConstructor3() {
99	jsr166	1.11	try {
100	jsr166	1.24	updaterFor("w");
101	dl	1.3	shouldThrow();
102	jsr166	1.25	} catch (IllegalArgumentException success) {}
103	dl	1.1	}
104
105	dl	1.3	/**
106	dl	1.30	* construction using private field from subclass throws RuntimeException
107			*/
108			public void testPrivateFieldInSubclass() {
109			AtomicLongFieldUpdaterTestSubclass s =
110			new AtomicLongFieldUpdaterTestSubclass();
111			s.checkPrivateAccess();
112			}
113
114			/**
115			* construction from unrelated class throws RuntimeException
116			*/
117			public void testUnrelatedClassAccess() {
118			UnrelatedClass s = new UnrelatedClass();
119			s.checkPrivateAccess();
120			}
121
122			/**
123	jsr166	1.18	* get returns the last value set or assigned
124	dl	1.3	*/
125	jsr166	1.12	public void testGetSet() {
126	dl	1.8	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
127	jsr166	1.24	a = updaterFor("x");
128	dl	1.1	x = 1;
129	jsr166	1.22	assertEquals(1, a.get(this));
130			a.set(this, 2);
131			assertEquals(2, a.get(this));
132			a.set(this, -3);
133			assertEquals(-3, a.get(this));
134	dl	1.1	}
135	dl	1.9
136			/**
137	jsr166	1.18	* get returns the last value lazySet by same thread
138	dl	1.9	*/
139	jsr166	1.12	public void testGetLazySet() {
140	dl	1.9	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
141	jsr166	1.24	a = updaterFor("x");
142	dl	1.9	x = 1;
143	jsr166	1.22	assertEquals(1, a.get(this));
144			a.lazySet(this, 2);
145			assertEquals(2, a.get(this));
146			a.lazySet(this, -3);
147			assertEquals(-3, a.get(this));
148	dl	1.9	}
149
150	dl	1.3	/**
151	dl	1.4	* compareAndSet succeeds in changing value if equal to expected else fails
152	dl	1.3	*/
153	jsr166	1.12	public void testCompareAndSet() {
154	dl	1.8	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
155	jsr166	1.24	a = updaterFor("x");
156	dl	1.1	x = 1;
157	jsr166	1.22	assertTrue(a.compareAndSet(this, 1, 2));
158			assertTrue(a.compareAndSet(this, 2, -4));
159			assertEquals(-4, a.get(this));
160			assertFalse(a.compareAndSet(this, -5, 7));
161			assertEquals(-4, a.get(this));
162			assertTrue(a.compareAndSet(this, -4, 7));
163			assertEquals(7, a.get(this));
164	dl	1.1	}
165
166	dl	1.4	/**
167	dl	1.30	* compareAndSet succeeds in changing protected field value if
168			* equal to expected else fails
169			*/
170			public void testCompareAndSetProtected() {
171			AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
172			a = updaterFor("protectedField");
173			protectedField = 1;
174			assertTrue(a.compareAndSet(this, 1, 2));
175			assertTrue(a.compareAndSet(this, 2, -4));
176			assertEquals(-4, a.get(this));
177			assertFalse(a.compareAndSet(this, -5, 7));
178			assertEquals(-4, a.get(this));
179			assertTrue(a.compareAndSet(this, -4, 7));
180			assertEquals(7, a.get(this));
181			}
182
183			/**
184			* compareAndSet succeeds in changing protected field value if
185			* equal to expected else fails
186			*/
187			public void testCompareAndSetProtectedInSubclass() {
188			AtomicLongFieldUpdaterTestSubclass s =
189			new AtomicLongFieldUpdaterTestSubclass();
190			s.checkCompareAndSetProtectedSub();
191			}
192
193			/**
194	dl	1.4	* compareAndSet in one thread enables another waiting for value
195			* to succeed
196			*/
197	jsr166	1.13	public void testCompareAndSetInMultipleThreads() throws Exception {
198	dl	1.4	x = 1;
199	jsr166	1.24	final AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
200			a = updaterFor("x");
201	dl	1.4
202	jsr166	1.14	Thread t = new Thread(new CheckedRunnable() {
203			public void realRun() {
204			while (!a.compareAndSet(AtomicLongFieldUpdaterTest.this, 2, 3))
205			Thread.yield();
206			}});
207	jsr166	1.13
208			t.start();
209			assertTrue(a.compareAndSet(this, 1, 2));
210			t.join(LONG_DELAY_MS);
211			assertFalse(t.isAlive());
212	jsr166	1.23	assertEquals(3, a.get(this));
213	dl	1.4	}
214
215	dl	1.3	/**
216	dl	1.4	* repeated weakCompareAndSet succeeds in changing value when equal
217	jsr166	1.10	* to expected
218	dl	1.3	*/
219	jsr166	1.12	public void testWeakCompareAndSet() {
220	dl	1.8	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
221	jsr166	1.24	a = updaterFor("x");
222	dl	1.1	x = 1;
223	jsr166	1.28	do {} while (!a.weakCompareAndSet(this, 1, 2));
224			do {} while (!a.weakCompareAndSet(this, 2, -4));
225	jsr166	1.22	assertEquals(-4, a.get(this));
226	jsr166	1.28	do {} while (!a.weakCompareAndSet(this, -4, 7));
227	jsr166	1.22	assertEquals(7, a.get(this));
228	dl	1.1	}
229
230	dl	1.3	/**
231	jsr166	1.18	* getAndSet returns previous value and sets to given value
232	dl	1.3	*/
233	jsr166	1.12	public void testGetAndSet() {
234	dl	1.8	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
235	jsr166	1.24	a = updaterFor("x");
236	dl	1.1	x = 1;
237	jsr166	1.22	assertEquals(1, a.getAndSet(this, 0));
238			assertEquals(0, a.getAndSet(this, -10));
239			assertEquals(-10, a.getAndSet(this, 1));
240	dl	1.1	}
241
242	dl	1.3	/**
243	dl	1.4	* getAndAdd returns previous value and adds given value
244	dl	1.3	*/
245	jsr166	1.12	public void testGetAndAdd() {
246	dl	1.8	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
247	jsr166	1.24	a = updaterFor("x");
248	dl	1.1	x = 1;
249	jsr166	1.22	assertEquals(1, a.getAndAdd(this, 2));
250			assertEquals(3, a.get(this));
251			assertEquals(3, a.getAndAdd(this, -4));
252			assertEquals(-1, a.get(this));
253	dl	1.1	}
254
255	dl	1.3	/**
256	dl	1.4	* getAndDecrement returns previous value and decrements
257	dl	1.3	*/
258	jsr166	1.12	public void testGetAndDecrement() {
259	dl	1.8	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
260	jsr166	1.24	a = updaterFor("x");
261	dl	1.1	x = 1;
262	jsr166	1.22	assertEquals(1, a.getAndDecrement(this));
263			assertEquals(0, a.getAndDecrement(this));
264			assertEquals(-1, a.getAndDecrement(this));
265	dl	1.1	}
266
267	dl	1.3	/**
268	dl	1.4	* getAndIncrement returns previous value and increments
269	dl	1.3	*/
270	jsr166	1.12	public void testGetAndIncrement() {
271	dl	1.8	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
272	jsr166	1.24	a = updaterFor("x");
273	dl	1.1	x = 1;
274	jsr166	1.22	assertEquals(1, a.getAndIncrement(this));
275			assertEquals(2, a.get(this));
276			a.set(this, -2);
277			assertEquals(-2, a.getAndIncrement(this));
278			assertEquals(-1, a.getAndIncrement(this));
279			assertEquals(0, a.getAndIncrement(this));
280			assertEquals(1, a.get(this));
281	dl	1.1	}
282
283	dl	1.3	/**
284	dl	1.4	* addAndGet adds given value to current, and returns current value
285	dl	1.3	*/
286	jsr166	1.12	public void testAddAndGet() {
287	dl	1.8	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
288	jsr166	1.24	a = updaterFor("x");
289	dl	1.1	x = 1;
290	jsr166	1.22	assertEquals(3, a.addAndGet(this, 2));
291			assertEquals(3, a.get(this));
292			assertEquals(-1, a.addAndGet(this, -4));
293			assertEquals(-1, a.get(this));
294	dl	1.1	}
295
296	dl	1.3	/**
297	jsr166	1.18	* decrementAndGet decrements and returns current value
298	dl	1.3	*/
299	jsr166	1.12	public void testDecrementAndGet() {
300	dl	1.8	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
301	jsr166	1.24	a = updaterFor("x");
302	dl	1.1	x = 1;
303	jsr166	1.22	assertEquals(0, a.decrementAndGet(this));
304			assertEquals(-1, a.decrementAndGet(this));
305			assertEquals(-2, a.decrementAndGet(this));
306			assertEquals(-2, a.get(this));
307	dl	1.1	}
308
309	dl	1.3	/**
310	dl	1.4	* incrementAndGet increments and returns current value
311	dl	1.3	*/
312	jsr166	1.12	public void testIncrementAndGet() {
313	dl	1.8	AtomicLongFieldUpdater<AtomicLongFieldUpdaterTest> a;
314	jsr166	1.24	a = updaterFor("x");
315	dl	1.1	x = 1;
316	jsr166	1.22	assertEquals(2, a.incrementAndGet(this));
317			assertEquals(2, a.get(this));
318			a.set(this, -2);
319			assertEquals(-1, a.incrementAndGet(this));
320			assertEquals(0, a.incrementAndGet(this));
321			assertEquals(1, a.incrementAndGet(this));
322			assertEquals(1, a.get(this));
323	dl	1.1	}
324
325			}