bug 290631: Introduced WeakHashSetSynchronized

core/org.eclipse.cdt.core.tests/misc/org/eclipse/cdt/utils/WeakHashSetTest.java

@@ -0,0 +1,124 @@
+/*******************************************************************************
+ *  Copyright (c) 2012, 2012 Andrew Gvozdev and others.
+ *  All rights reserved. This program and the accompanying materials
+ *  are made available under the terms of the Eclipse Public License v1.0
+ *  which accompanies this distribution, and is available at
+ *  http://www.eclipse.org/legal/epl-v10.html
+ *
+ *  Contributors:
+ *      Andrew Gvozdev - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.utils;
+
+import junit.framework.Test;
+import junit.framework.TestCase;
+import junit.framework.TestSuite;
+
+import org.eclipse.cdt.internal.core.WeakHashSet;
+import org.eclipse.cdt.internal.core.WeakHashSetSynchronized;
+
+/**
+ * Test suite to test {@link WeakHashSet}.
+ */
+public class WeakHashSetTest extends TestCase {
+	/**
+	 * Sample mock class with specialized hashCode()
+	 */
+	private class MockClass {
+		private String str;
+		private MockClass(String str) {
+			super();
+			this.str = str;
+		}
+		@Override
+		public int hashCode() {
+			// for test purpose make hashcodes equal for all "str" stating with the same letter
+			// note that "equals()" still reports difference
+			String s = str.substring(0,1);
+			return s.hashCode();
+		}
+		@Override
+		public boolean equals(Object obj) {
+			MockClass other = (MockClass) obj;
+			return str.equals(other.str);
+		}
+	}
+
+	public static Test suite() {
+		return new TestSuite(WeakHashSetTest.class);
+	}
+
+	/**
+	 * Test basic methods of {@link WeakHashSet}.
+	 */
+	public void testHashSetBasic() {
+		// create sample objects
+		WeakHashSet<MockClass> weakSet = new WeakHashSet<MockClass>();
+		MockClass a1 = new MockClass("a");
+		MockClass a2 = new MockClass("a");
+
+		// check contains()
+		assertEquals(false, weakSet.contains(a1));
+		assertEquals(null, weakSet.get(a1));
+		// check add() and get()
+		assertSame(a1, weakSet.add(a1));
+		assertSame(a1, weakSet.add(a2));
+		assertSame(a1, weakSet.get(a1));
+		assertSame(a1, weakSet.get(a2));
+		assertEquals(true, weakSet.contains(a1));
+		assertEquals(true, weakSet.contains(a2));
+		// check remove()
+		MockClass aOld = weakSet.remove(a2);
+		assertSame(a1, aOld);
+		assertEquals(null, weakSet.get(a1));
+		assertSame(a2, weakSet.add(a2));
+		assertSame(a2, weakSet.add(a1));
+
+		// create sample objects with the same hashcode
+		MockClass aa = new MockClass("aa");
+		MockClass ab = new MockClass("ab");
+		assertEquals(aa.hashCode(), ab.hashCode());
+		assertEquals(false, aa.equals(ab));
+		// check add() and get()
+		assertEquals(false, weakSet.contains(aa));
+		assertEquals(false, weakSet.contains(ab));
+		assertEquals(null, weakSet.get(aa));
+		assertEquals(null, weakSet.get(ab));
+		assertSame(aa, weakSet.add(aa));
+		assertSame(ab, weakSet.add(ab));
+		assertEquals(true, weakSet.contains(aa));
+		assertEquals(true, weakSet.contains(ab));
+		assertSame(aa, weakSet.get(aa));
+		assertSame(ab, weakSet.get(ab));
+	}
+
+	/**
+	 * Test synchronized {@link WeakHashSetSynchronized}.
+	 * Note that regular {@link WeakHashSet} would fail the test.
+	 */
+	public void testHashSetSyncronization() throws Exception {
+		final WeakHashSet<Integer> weakSet = new WeakHashSetSynchronized<Integer>(1);
+
+		Thread[] threads= new Thread[5000];
+		for (int i = 0; i < threads.length; i++) {
+			final Integer n = i;
+			Thread t= new Thread() {
+				@Override
+				public void run() {
+					weakSet.add(n);
+				}
+			};
+			threads[i] = t;
+			t.start();
+		}
+
+		for (int i = 0; i < threads.length; i++) {
+			threads[i].join();
+		}
+		assertEquals(threads.length, weakSet.size());
+
+		for (int i = 0; i < threads.length; i++) {
+			assertEquals(true, weakSet.contains(i));
+		}
+	}
+}

core/org.eclipse.cdt.core.tests/suite/org/eclipse/cdt/core/suite/AutomatedIntegrationSuite.java

@@ -35,6 +35,7 @@ import org.eclipse.cdt.internal.pdom.tests.PDOMTests;
 import org.eclipse.cdt.utils.CdtVariableResolverTest;
 import org.eclipse.cdt.utils.CommandLineUtilTest;
 import org.eclipse.cdt.utils.FindProgramLocationTest;
+import org.eclipse.cdt.utils.WeakHashSetTest;
 
 /**
  * @author vhirsl
@@ -75,6 +76,7 @@ public class AutomatedIntegrationSuite extends TestSuite {
 		suite.addTest(RewriteTests.suite());
 		suite.addTest(CdtVariableResolverTest.suite());
 		suite.addTest(CommandLineUtilTest.suite());
+		suite.addTest(WeakHashSetTest.suite());
 		suite.addTest(FindProgramLocationTest.suite());
 		suite.addTest(EFSExtensionTests.suite());
 

core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/language/settings/providers/LanguageSettingsStorage.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2011 Andrew Gvozdev and others.
+ * Copyright (c) 2011, 2012 Andrew Gvozdev and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -22,6 +22,7 @@ import java.util.Set;
 import org.eclipse.cdt.core.settings.model.ICLanguageSettingEntry;
 import org.eclipse.cdt.core.settings.model.ICSettingEntry;
 import org.eclipse.cdt.internal.core.WeakHashSet;
+import org.eclipse.cdt.internal.core.WeakHashSetSynchronized;
 
 /**
  * The class representing the (in-memory) storage for language settings entries {@link ICLanguageSettingEntry}.
@@ -39,12 +40,7 @@ public class LanguageSettingsStorage implements Cloneable {
 	 * at the expense of CPU time. WeakHashSet handles garbage collection when a list is not
 	 * referenced anywhere else. See JavaDoc {@link java.lang.ref.WeakReference} about weak reference objects.
 	 */
-	private static WeakHashSet<List<ICLanguageSettingEntry>> listPool = new WeakHashSet<List<ICLanguageSettingEntry>>() {
-		@Override
-		public synchronized List<ICLanguageSettingEntry> add(List<ICLanguageSettingEntry> list) {
-			return super.add(list);
-		}
-	};
+	private static WeakHashSet<List<ICLanguageSettingEntry>> listPool = new WeakHashSetSynchronized<List<ICLanguageSettingEntry>>();
 
 	/**
 	 * Returns the list of setting entries for the given resource and language.

core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/settings/model/util/CDataUtil.java

@@ -58,6 +58,7 @@ import org.eclipse.cdt.core.settings.model.extension.CTargetPlatformData;
 import org.eclipse.cdt.core.settings.model.extension.impl.CDataFactory;
 import org.eclipse.cdt.core.settings.model.extension.impl.CDefaultLanguageData;
 import org.eclipse.cdt.internal.core.WeakHashSet;
+import org.eclipse.cdt.internal.core.WeakHashSetSynchronized;
 import org.eclipse.cdt.internal.core.settings.model.ExceptionFactory;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.ProjectScope;
@@ -82,12 +83,7 @@ public class CDataUtil {
 	 * at the expense of CPU time. WeakHashSet handles garbage collection when a list is not
 	 * referenced anywhere else. See JavaDoc {@link java.lang.ref.WeakReference} about weak reference objects.
 	 */
-	private static WeakHashSet<ICSettingEntry> settingEntriesPool = new WeakHashSet<ICSettingEntry>() {
-		@Override
-		public synchronized ICSettingEntry add(ICSettingEntry entry) {
-			return super.add(entry);
-		}
-	};
+	private static WeakHashSet<ICSettingEntry> settingEntriesPool = new WeakHashSetSynchronized<ICSettingEntry>();
 
 	public static int genRandomNumber(){
 		if (randomNumber == null) {

core/org.eclipse.cdt.core/utils/org/eclipse/cdt/internal/core/WeakHashSetSynchronized.java

@@ -0,0 +1,45 @@
+/*******************************************************************************
+ *  Copyright (c) 2012 Andrew Gvozdev and others.
+ *  All rights reserved. This program and the accompanying materials
+ *  are made available under the terms of the Eclipse Public License v1.0
+ *  which accompanies this distribution, and is available at
+ *  http://www.eclipse.org/legal/epl-v10.html
+ *
+ *  Contributors:
+ *     Andrew Gvozdev - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.internal.core;
+
+/**
+ * A synchronized hashset whose values can be garbage collected.
+ */
+public class WeakHashSetSynchronized<T> extends WeakHashSet<T> {
+	/**
+	 * Constructor.
+	 */
+	public WeakHashSetSynchronized() {
+		super(5);
+	}
+
+	/**
+	 * Constructor.
+	 *
+	 * @param size - initial capacity.
+	 */
+	public WeakHashSetSynchronized(int size) {
+		super(size);
+	}
+
+	@Override
+	synchronized public T add(T obj) {
+		return super.add(obj);
+	}
+	@Override
+	synchronized public T get(T obj) {
+		return super.get(obj);
+	}
+	@Override
+	synchronized public T remove(T obj) {
+		return super.remove(obj);
+	}
+}