util/WeakHashMap/GCDuringIteration.java

/*
 * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * @test
 * @bug 6499848
 * @summary Check that iterators work properly in the presence of
 *          concurrent finalization and removal of elements.
 * @key randomness
 */

import java.util.*;
import java.util.concurrent.CountDownLatch;

public class GCDuringIteration {
    private static void waitForFinalizersToRun() {
        for (int i = 0; i < 2; i++)
            tryWaitForFinalizersToRun();
    }

    private static void tryWaitForFinalizersToRun() {
        System.gc();
        final CountDownLatch fin = new CountDownLatch(1);
        new Object() { protected void finalize() { fin.countDown(); }};
        System.gc();
        try { fin.await(); }
        catch (InterruptedException ie) { throw new Error(ie); }
    }

    // A class with the traditional pessimal hashCode implementation,
    // to ensure that all instances end up in the same bucket.
    static class Foo { public int hashCode() { return 42; }}

    <K,V> void put(Map<K,V> map, K k, V v) {
        check(! map.containsKey(k));
        equal(map.get(k), null);
        equal(map.put(k, v), null);
        equal(map.get(k), v);
        check(map.containsKey(k));
        equal(map.put(k, v), v);
        equal(map.get(k), v);
        check(map.containsKey(k));
        check(! map.isEmpty());
        equal(map.keySet().iterator().next(), k);
        equal(map.values().iterator().next(), v);
    }

    void checkIterator(final Iterator<Map.Entry<Foo, Integer>> it, int first) {
        final Random rnd = new Random();
        for (int i = first; i >= 0; --i) {
            if (rnd.nextBoolean()) check(it.hasNext());
            equal(it.next().getValue(), i);
        }
        if (rnd.nextBoolean())
            THROWS(NoSuchElementException.class,
                   new F(){void f(){it.next();}});
        if (rnd.nextBoolean())
            check(! it.hasNext());
    }

    <K,V> V firstValue(Map<K,V> map) {
        return map.values().iterator().next();
    }

    void test(String[] args) throws Throwable {
        final int n = 10;
        // Create array of strong refs
        final Foo[] foos = new Foo[2*n];
        final Map<Foo,Integer> map = new WeakHashMap<Foo,Integer>(foos.length);
        check(map.isEmpty());
        equal(map.size(), 0);

        for (int i = 0; i < foos.length; i++) {
            Foo foo = new Foo();
            foos[i] = foo;
            put(map, foo, i);
        }
        equal(map.size(), foos.length);

        {
            int first = firstValue(map);
            final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
            foos[first] = null;
            for (int i = 0; i < 10 && map.size() != first; i++)
                tryWaitForFinalizersToRun();
            equal(map.size(), first);
            checkIterator(it, first-1);
            equal(map.size(), first);
            equal(firstValue(map), first-1);
        }

        {
            int first = firstValue(map);
            final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
            it.next();          // protects first entry
            System.out.println(map.values());
            foos[first] = null;
            tryWaitForFinalizersToRun();
            equal(map.size(), first+1);
            System.out.println(map.values());
            checkIterator(it, first-1);
            // first entry no longer protected
            for (int i = 0; i < 10 && map.size() != first; i++)
                tryWaitForFinalizersToRun();
            equal(map.size(), first);
            equal(firstValue(map), first-1);
        }

        {
            int first = firstValue(map);
            final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
            it.next();          // protects first entry
            System.out.println(map.values());
            foos[first] = foos[first-1] = null;
            tryWaitForFinalizersToRun();
            equal(map.size(), first);
            equal(firstValue(map), first);
            System.out.println(map.values());
            checkIterator(it, first-2);
            // first entry no longer protected
            for (int i = 0; i < 10 && map.size() != first-1; i++)
                tryWaitForFinalizersToRun();
            equal(map.size(), first-1);
            equal(firstValue(map), first-2);
        }

        {
            int first = firstValue(map);
            final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
            it.next();          // protects first entry
            it.hasNext();       // protects second entry
            System.out.println(map.values());
            foos[first] = foos[first-1] = null;
            tryWaitForFinalizersToRun();
            equal(firstValue(map), first);
            equal(map.size(), first+1);
            System.out.println(map.values());
            checkIterator(it, first-1);
            // first entry no longer protected
            for (int i = 0; i < 10 && map.size() != first-1; i++)
                tryWaitForFinalizersToRun();
            equal(map.size(), first-1);
            equal(firstValue(map), first-2);
        }

        {
            int first = firstValue(map);
            final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
            it.next();          // protects first entry
            System.out.println(map.values());
            foos[first] = foos[first-1] = null;
            tryWaitForFinalizersToRun();
            it.remove();
            equal(firstValue(map), first-2);
            equal(map.size(), first-1);
            System.out.println(map.values());
            checkIterator(it, first-2);
            // first entry no longer protected
            for (int i = 0; i < 10 && map.size() != first-1; i++)
                tryWaitForFinalizersToRun();
            equal(map.size(), first-1);
            equal(firstValue(map), first-2);
        }

        {
            int first = firstValue(map);
            final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
            it.next();          // protects first entry
            it.remove();
            it.hasNext();       // protects second entry
            System.out.println(map.values());
            foos[first] = foos[first-1] = null;
            tryWaitForFinalizersToRun();
            equal(firstValue(map), first-1);
            equal(map.size(), first);
            System.out.println(map.values());
            checkIterator(it, first-1);
            for (int i = 0; i < 10 && map.size() != first-1; i++)
                tryWaitForFinalizersToRun();
            equal(map.size(), first-1);
            equal(firstValue(map), first-2);
        }

        {
            int first = firstValue(map);
            final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
            it.hasNext();       // protects first entry
            Arrays.fill(foos, null);
            tryWaitForFinalizersToRun();
            equal(map.size(), 1);
            System.out.println(map.values());
            equal(it.next().getValue(), first);
            check(! it.hasNext());
            for (int i = 0; i < 10 && map.size() != 0; i++)
                tryWaitForFinalizersToRun();
            equal(map.size(), 0);
            check(map.isEmpty());
        }
    }

    //--------------------- Infrastructure ---------------------------
    volatile int passed = 0, failed = 0;
    void pass() {passed++;}
    void fail() {failed++; Thread.dumpStack();}
    void fail(String msg) {System.err.println(msg); fail();}
    void unexpected(Throwable t) {failed++; t.printStackTrace();}
    void check(boolean cond) {if (cond) pass(); else fail();}
    void equal(Object x, Object y) {
        if (x == null ? y == null : x.equals(y)) pass();
        else fail(x + " not equal to " + y);}
    public static void main(String[] args) throws Throwable {
        new GCDuringIteration().instanceMain(args);}
    void instanceMain(String[] args) throws Throwable {
        try {test(args);} catch (Throwable t) {unexpected(t);}
        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
        if (failed > 0) throw new AssertionError("Some tests failed");}
    abstract class F {abstract void f() throws Throwable;}
    void THROWS(Class<? extends Throwable> k, F... fs) {
        for (F f : fs)
            try {f.f(); fail("Expected " + k.getName() + " not thrown");}
            catch (Throwable t) {
                if (k.isAssignableFrom(t.getClass())) pass();
                else unexpected(t);}}
}
Revision:	1.6
Committed:	Mon May 25 19:06:26 2015 UTC (9 years ago) by jsr166
Branch:	MAIN
Changes since 1.5:	+1 -2 lines
Log Message:	unignore
#	User	Rev	Content
1	jsr166	1.1	/*
2	jsr166	1.5	* Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
3	jsr166	1.1	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4			*
5			* This code is free software; you can redistribute it and/or modify it
6			* under the terms of the GNU General Public License version 2 only, as
7			* published by the Free Software Foundation.
8			*
9			* This code is distributed in the hope that it will be useful, but WITHOUT
10			* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11			* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12			* version 2 for more details (a copy is included in the LICENSE file that
13			* accompanied this code).
14			*
15			* You should have received a copy of the GNU General Public License version
16			* 2 along with this work; if not, write to the Free Software Foundation,
17			* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18			*
19	jsr166	1.2	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20			* or visit www.oracle.com if you need additional information or have any
21			* questions.
22	jsr166	1.1	*/
23
24			/*
25			* @test
26			* @bug 6499848
27			* @summary Check that iterators work properly in the presence of
28			* concurrent finalization and removal of elements.
29	jsr166	1.5	* @key randomness
30	jsr166	1.1	*/
31
32			import java.util.*;
33			import java.util.concurrent.CountDownLatch;
34
35			public class GCDuringIteration {
36	jsr166	1.3	private static void waitForFinalizersToRun() {
37	jsr166	1.4	for (int i = 0; i < 2; i++)
38			tryWaitForFinalizersToRun();
39			}
40
41			private static void tryWaitForFinalizersToRun() {
42			System.gc();
43			final CountDownLatch fin = new CountDownLatch(1);
44			new Object() { protected void finalize() { fin.countDown(); }};
45			System.gc();
46			try { fin.await(); }
47			catch (InterruptedException ie) { throw new Error(ie); }
48	jsr166	1.1	}
49
50			// A class with the traditional pessimal hashCode implementation,
51			// to ensure that all instances end up in the same bucket.
52			static class Foo { public int hashCode() { return 42; }}
53
54			<K,V> void put(Map<K,V> map, K k, V v) {
55			check(! map.containsKey(k));
56			equal(map.get(k), null);
57			equal(map.put(k, v), null);
58			equal(map.get(k), v);
59			check(map.containsKey(k));
60			equal(map.put(k, v), v);
61			equal(map.get(k), v);
62			check(map.containsKey(k));
63			check(! map.isEmpty());
64			equal(map.keySet().iterator().next(), k);
65			equal(map.values().iterator().next(), v);
66			}
67
68			void checkIterator(final Iterator<Map.Entry<Foo, Integer>> it, int first) {
69			final Random rnd = new Random();
70			for (int i = first; i >= 0; --i) {
71			if (rnd.nextBoolean()) check(it.hasNext());
72			equal(it.next().getValue(), i);
73			}
74			if (rnd.nextBoolean())
75			THROWS(NoSuchElementException.class,
76			new F(){void f(){it.next();}});
77			if (rnd.nextBoolean())
78			check(! it.hasNext());
79			}
80
81			<K,V> V firstValue(Map<K,V> map) {
82			return map.values().iterator().next();
83			}
84
85			void test(String[] args) throws Throwable {
86			final int n = 10;
87			// Create array of strong refs
88			final Foo[] foos = new Foo[2*n];
89			final Map<Foo,Integer> map = new WeakHashMap<Foo,Integer>(foos.length);
90			check(map.isEmpty());
91			equal(map.size(), 0);
92
93			for (int i = 0; i < foos.length; i++) {
94			Foo foo = new Foo();
95			foos[i] = foo;
96			put(map, foo, i);
97			}
98			equal(map.size(), foos.length);
99
100			{
101			int first = firstValue(map);
102			final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
103	jsr166	1.4	foos[first] = null;
104			for (int i = 0; i < 10 && map.size() != first; i++)
105			tryWaitForFinalizersToRun();
106	jsr166	1.1	equal(map.size(), first);
107			checkIterator(it, first-1);
108			equal(map.size(), first);
109			equal(firstValue(map), first-1);
110			}
111
112			{
113			int first = firstValue(map);
114			final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
115			it.next(); // protects first entry
116			System.out.println(map.values());
117	jsr166	1.4	foos[first] = null;
118	jsr166	1.6	tryWaitForFinalizersToRun();
119	jsr166	1.1	equal(map.size(), first+1);
120			System.out.println(map.values());
121			checkIterator(it, first-1);
122	jsr166	1.4	// first entry no longer protected
123			for (int i = 0; i < 10 && map.size() != first; i++)
124			tryWaitForFinalizersToRun();
125	jsr166	1.1	equal(map.size(), first);
126			equal(firstValue(map), first-1);
127			}
128
129			{
130			int first = firstValue(map);
131			final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
132			it.next(); // protects first entry
133			System.out.println(map.values());
134	jsr166	1.4	foos[first] = foos[first-1] = null;
135			tryWaitForFinalizersToRun();
136	jsr166	1.1	equal(map.size(), first);
137			equal(firstValue(map), first);
138			System.out.println(map.values());
139			checkIterator(it, first-2);
140	jsr166	1.4	// first entry no longer protected
141			for (int i = 0; i < 10 && map.size() != first-1; i++)
142			tryWaitForFinalizersToRun();
143	jsr166	1.1	equal(map.size(), first-1);
144			equal(firstValue(map), first-2);
145			}
146
147			{
148			int first = firstValue(map);
149			final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
150			it.next(); // protects first entry
151			it.hasNext(); // protects second entry
152			System.out.println(map.values());
153	jsr166	1.4	foos[first] = foos[first-1] = null;
154			tryWaitForFinalizersToRun();
155	jsr166	1.1	equal(firstValue(map), first);
156			equal(map.size(), first+1);
157			System.out.println(map.values());
158			checkIterator(it, first-1);
159	jsr166	1.4	// first entry no longer protected
160			for (int i = 0; i < 10 && map.size() != first-1; i++)
161			tryWaitForFinalizersToRun();
162	jsr166	1.1	equal(map.size(), first-1);
163			equal(firstValue(map), first-2);
164			}
165
166			{
167			int first = firstValue(map);
168			final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
169			it.next(); // protects first entry
170			System.out.println(map.values());
171	jsr166	1.4	foos[first] = foos[first-1] = null;
172			tryWaitForFinalizersToRun();
173	jsr166	1.1	it.remove();
174			equal(firstValue(map), first-2);
175			equal(map.size(), first-1);
176			System.out.println(map.values());
177			checkIterator(it, first-2);
178	jsr166	1.4	// first entry no longer protected
179			for (int i = 0; i < 10 && map.size() != first-1; i++)
180			tryWaitForFinalizersToRun();
181	jsr166	1.1	equal(map.size(), first-1);
182			equal(firstValue(map), first-2);
183			}
184
185			{
186			int first = firstValue(map);
187			final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
188			it.next(); // protects first entry
189			it.remove();
190			it.hasNext(); // protects second entry
191			System.out.println(map.values());
192	jsr166	1.4	foos[first] = foos[first-1] = null;
193			tryWaitForFinalizersToRun();
194	jsr166	1.1	equal(firstValue(map), first-1);
195			equal(map.size(), first);
196			System.out.println(map.values());
197			checkIterator(it, first-1);
198	jsr166	1.4	for (int i = 0; i < 10 && map.size() != first-1; i++)
199			tryWaitForFinalizersToRun();
200	jsr166	1.1	equal(map.size(), first-1);
201			equal(firstValue(map), first-2);
202			}
203
204			{
205			int first = firstValue(map);
206			final Iterator<Map.Entry<Foo,Integer>> it = map.entrySet().iterator();
207			it.hasNext(); // protects first entry
208			Arrays.fill(foos, null);
209	jsr166	1.4	tryWaitForFinalizersToRun();
210	jsr166	1.1	equal(map.size(), 1);
211			System.out.println(map.values());
212			equal(it.next().getValue(), first);
213			check(! it.hasNext());
214	jsr166	1.4	for (int i = 0; i < 10 && map.size() != 0; i++)
215			tryWaitForFinalizersToRun();
216	jsr166	1.1	equal(map.size(), 0);
217			check(map.isEmpty());
218			}
219			}
220
221			//--------------------- Infrastructure ---------------------------
222			volatile int passed = 0, failed = 0;
223			void pass() {passed++;}
224			void fail() {failed++; Thread.dumpStack();}
225			void fail(String msg) {System.err.println(msg); fail();}
226			void unexpected(Throwable t) {failed++; t.printStackTrace();}
227			void check(boolean cond) {if (cond) pass(); else fail();}
228			void equal(Object x, Object y) {
229			if (x == null ? y == null : x.equals(y)) pass();
230			else fail(x + " not equal to " + y);}
231			public static void main(String[] args) throws Throwable {
232			new GCDuringIteration().instanceMain(args);}
233			void instanceMain(String[] args) throws Throwable {
234			try {test(args);} catch (Throwable t) {unexpected(t);}
235			System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
236			if (failed > 0) throw new AssertionError("Some tests failed");}
237			abstract class F {abstract void f() throws Throwable;}
238			void THROWS(Class<? extends Throwable> k, F... fs) {
239			for (F f : fs)
240			try {f.f(); fail("Expected " + k.getName() + " not thrown");}
241			catch (Throwable t) {
242			if (k.isAssignableFrom(t.getClass())) pass();
243			else unexpected(t);}}
244			}