jdk/test/java/util/WeakHashMap/GCDuringIteration.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2007, 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
  * @ignore until 6842353 is resolved
  * @summary Check that iterators work properly in the presence of
  *          concurrent finalization and removal of elements.
  */

 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);}}
 }
	/*
	* Copyright (c) 2007, 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
	* @ignore until 6842353 is resolved
	* @summary Check that iterators work properly in the presence of
	* concurrent finalization and removal of elements.
	*/

	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);}}
	}