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From scolebou...@apache.org
Subject cvs commit: jakarta-commons/collections/src/java/org/apache/commons/collections/map ReferenceIdentityMap.java
Date Tue, 27 Apr 2004 21:37:33 GMT
scolebourne    2004/04/27 14:37:32

  Added:       collections/src/test/org/apache/commons/collections/map
                        TestReferenceIdentityMap.java
               collections/data/test
                        ReferenceIdentityMap.fullCollection.version3.1.obj
                        ReferenceIdentityMap.emptyCollection.version3.1.obj
               collections/src/java/org/apache/commons/collections/map
                        ReferenceIdentityMap.java
  Log:
  Add ReferenceIdentityMap
  
  Revision  Changes    Path
  1.1                  jakarta-commons/collections/src/test/org/apache/commons/collections/map/TestReferenceIdentityMap.java
  
  Index: TestReferenceIdentityMap.java
  ===================================================================
  /*
   *  Copyright 2004 The Apache Software Foundation
   *
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  package org.apache.commons.collections.map;
  
  import java.lang.ref.WeakReference;
  import java.util.Iterator;
  import java.util.Map;
  
  import junit.framework.Test;
  
  import org.apache.commons.collections.BulkTest;
  import org.apache.commons.collections.IterableMap;
  
  /**
   * Tests for ReferenceIdentityMap. 
   * 
   * @version $Revision: 1.1 $
   *
   * @author Paul Jack
   * @author Stephen Colebourne
   */
  public class TestReferenceIdentityMap extends AbstractTestIterableMap {
  
      private static final Integer I1A = new Integer(1);
      private static final Integer I1B = new Integer(1);
      private static final Integer I2A = new Integer(2);
      private static final Integer I2B = new Integer(2);
  
      public TestReferenceIdentityMap(String testName) {
          super(testName);
      }
  
      public static Test suite() {
          return BulkTest.makeSuite(TestReferenceIdentityMap.class);
      }
  
      public static void main(String args[]) {
          String[] testCaseName = { TestReferenceIdentityMap.class.getName() };
          junit.textui.TestRunner.main(testCaseName);
      }
  
      public Map makeEmptyMap() {
          ReferenceIdentityMap map = new ReferenceIdentityMap(ReferenceIdentityMap.WEAK, ReferenceIdentityMap.WEAK);
          return map;
      }
      
      public Map makeConfirmedMap() {
          // Testing against another [collections] class generally isn't a good idea,
          // but the alternative is a JDK1.4 dependency in the tests
          return new IdentityMap();
      }
  
      public boolean isAllowNullKey() {
          return false;
      }
  
      public boolean isAllowNullValue() {
          return false;
      }
  
      //-----------------------------------------------------------------------
      public void testBasics() {
          IterableMap map = new ReferenceIdentityMap(ReferenceIdentityMap.HARD, ReferenceIdentityMap.HARD);
          assertEquals(0, map.size());
          
          map.put(I1A, I2A);
          assertEquals(1, map.size());
          assertSame(I2A, map.get(I1A));
          assertSame(null, map.get(I1B));
          assertEquals(true, map.containsKey(I1A));
          assertEquals(false, map.containsKey(I1B));
          assertEquals(true, map.containsValue(I2A));
          assertEquals(false, map.containsValue(I2B));
          
          map.put(I1A, I2B);
          assertEquals(1, map.size());
          assertSame(I2B, map.get(I1A));
          assertSame(null, map.get(I1B));
          assertEquals(true, map.containsKey(I1A));
          assertEquals(false, map.containsKey(I1B));
          assertEquals(false, map.containsValue(I2A));
          assertEquals(true, map.containsValue(I2B));
          
          map.put(I1B, I2B);
          assertEquals(2, map.size());
          assertSame(I2B, map.get(I1A));
          assertSame(I2B, map.get(I1B));
          assertEquals(true, map.containsKey(I1A));
          assertEquals(true, map.containsKey(I1B));
          assertEquals(false, map.containsValue(I2A));
          assertEquals(true, map.containsValue(I2B));
      }
      
      //-----------------------------------------------------------------------
      public void testHashEntry() {
          IterableMap map = new ReferenceIdentityMap(ReferenceIdentityMap.HARD, ReferenceIdentityMap.HARD);
          
          map.put(I1A, I2A);
          map.put(I1B, I2A);
          
          Map.Entry entry1 = (Map.Entry) map.entrySet().iterator().next();
          Iterator it = map.entrySet().iterator();
          Map.Entry entry2 = (Map.Entry) it.next();
          Map.Entry entry3 = (Map.Entry) it.next();
          
          assertEquals(true, entry1.equals(entry2));
          assertEquals(true, entry2.equals(entry1));
          assertEquals(false, entry1.equals(entry3));
      }
      
      
      //-----------------------------------------------------------------------
     // Unfortunately, these tests all rely on System.gc(), which is
     // not reliable across platforms.  Not sure how to code the tests
     // without using System.gc() though...
     // They all passed on my platform though. :)
  /*
      public void testPurge() {
          ReferenceIdentityMap map = new ReferenceIdentityMap(ReferenceIdentityMap.WEAK, ReferenceIdentityMap.WEAK);
          Object[] hard = new Object[10];
          for (int i = 0; i < hard.length; i++) {
              hard[i] = new Object();
              map.put(hard[i], new Object());
          }
          System.gc();
          assertTrue("map should be empty after purge of weak values", map.isEmpty());
  
          for (int i = 0; i < hard.length; i++) {
              map.put(new Object(), hard[i]);
          }
          System.gc();
          assertTrue("map should be empty after purge of weak keys", map.isEmpty());
  
          for (int i = 0; i < hard.length; i++) {
              map.put(new Object(), hard[i]);
              map.put(hard[i], new Object());
          }
  
          System.gc();
          assertTrue("map should be empty after purge of weak keys and values", map.isEmpty());
      }
  
  
      public void testGetAfterGC() {
          ReferenceIdentityMap map = new ReferenceIdentityMap(ReferenceIdentityMap.WEAK, ReferenceIdentityMap.WEAK);
          for (int i = 0; i < 10; i++) {
              map.put(new Integer(i), new Integer(i));
          }
  
          System.gc();
          for (int i = 0; i < 10; i++) {
              Integer I = new Integer(i);
              assertTrue("map.containsKey should return false for GC'd element", !map.containsKey(I));
              assertTrue("map.get should return null for GC'd element", map.get(I) == null);
          }
      }
  
  
      public void testEntrySetIteratorAfterGC() {
          ReferenceIdentityMap map = new ReferenceIdentityMap(ReferenceIdentityMap.WEAK, ReferenceIdentityMap.WEAK);
          Object[] hard = new Object[10];
          for (int i = 0; i < 10; i++) {
              hard[i] = new Integer(10 + i);
              map.put(new Integer(i), new Integer(i));
              map.put(hard[i], hard[i]);
          }
  
          System.gc();
          Iterator iterator = map.entrySet().iterator();
          while (iterator.hasNext()) {
              Map.Entry entry = (Map.Entry)iterator.next();
              Integer key = (Integer)entry.getKey();
              Integer value = (Integer)entry.getValue();
              assertTrue("iterator should skip GC'd keys", key.intValue() >= 10);
              assertTrue("iterator should skip GC'd values", value.intValue() >= 10);
          }
  
      }
  
      public void testMapIteratorAfterGC() {
          ReferenceIdentityMap map = new ReferenceIdentityMap(ReferenceIdentityMap.WEAK, ReferenceIdentityMap.WEAK);
          Object[] hard = new Object[10];
          for (int i = 0; i < 10; i++) {
              hard[i] = new Integer(10 + i);
              map.put(new Integer(i), new Integer(i));
              map.put(hard[i], hard[i]);
          }
  
          System.gc();
          MapIterator iterator = map.mapIterator();
          while (iterator.hasNext()) {
              Object key1 = iterator.next();
              Integer key = (Integer) iterator.getKey();
              Integer value = (Integer) iterator.getValue();
              assertTrue("iterator keys should match", key == key1);
              assertTrue("iterator should skip GC'd keys", key.intValue() >= 10);
              assertTrue("iterator should skip GC'd values", value.intValue() >= 10);
          }
  
      }
  
      public void testMapIteratorAfterGC2() {
          ReferenceIdentityMap map = new ReferenceIdentityMap(ReferenceIdentityMap.WEAK, ReferenceIdentityMap.WEAK);
          Object[] hard = new Object[10];
          for (int i = 0; i < 10; i++) {
              hard[i] = new Integer(10 + i);
              map.put(new Integer(i), new Integer(i));
              map.put(hard[i], hard[i]);
          }
  
          MapIterator iterator = map.mapIterator();
          while (iterator.hasNext()) {
              Object key1 = iterator.next();
              System.gc();
              Integer key = (Integer) iterator.getKey();
              Integer value = (Integer) iterator.getValue();
              assertTrue("iterator keys should match", key == key1);
              assertTrue("iterator should skip GC'd keys", key.intValue() >= 10);
              assertTrue("iterator should skip GC'd values", value.intValue() >= 10);
          }
  
      }
  */
  /*
      // Uncomment to create test files in /data/test
      public void testCreateTestFiles() throws Exception {
          ReferenceIdentityMap m = (ReferenceIdentityMap) makeEmptyMap();
          writeExternalFormToDisk(m, getCanonicalEmptyCollectionName(m));
          m = (ReferenceIdentityMap) makeFullMap();
          writeExternalFormToDisk(m, getCanonicalFullCollectionName(m));
      }
  */
  
  
      public String getCompatibilityVersion() {
          return "3.1";
      }
  
      /** Tests whether purge values setting works */
      public void testPurgeValues() throws Exception {
          // many thanks to Juozas Baliuka for suggesting this method
          Object key = new Object();
          Object value = new Object();
          
          WeakReference keyReference = new WeakReference(key);
          WeakReference valueReference = new WeakReference(value);
          
          Map testMap = new ReferenceIdentityMap(ReferenceIdentityMap.WEAK, ReferenceIdentityMap.HARD,
true);
          testMap.put(key, value);
          
          assertEquals("In map", value, testMap.get(key));
          assertNotNull("Weak reference released early (1)", keyReference.get());
          assertNotNull("Weak reference released early (2)", valueReference.get());
          
          // dereference strong references
          key = null;
          value = null;
          
          int iterations = 0;
          int bytz = 2;
          while(true) {
              System.gc();
              if(iterations++ > 50){
                  fail("Max iterations reached before resource released.");
              }
              testMap.isEmpty();
              if( 
                  keyReference.get() == null &&
                  valueReference.get() == null) {
                  break;
                  
              } else {
                  // create garbage:
                  byte[] b =  new byte[bytz];
                  bytz = bytz * 2;
              }
          }
      }
  }
  
  
  
  1.1                  jakarta-commons/collections/data/test/ReferenceIdentityMap.fullCollection.version3.1.obj
  
  	<<Binary file>>
  
  
  1.1                  jakarta-commons/collections/data/test/ReferenceIdentityMap.emptyCollection.version3.1.obj
  
  	<<Binary file>>
  
  
  1.1                  jakarta-commons/collections/src/java/org/apache/commons/collections/map/ReferenceIdentityMap.java
  
  Index: ReferenceIdentityMap.java
  ===================================================================
  /*
   *  Copyright 2004 The Apache Software Foundation
   *
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  package org.apache.commons.collections.map;
  
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.Serializable;
  import java.lang.ref.Reference;
  
  /**
   * A <code>Map</code> implementation that allows mappings to be
   * removed by the garbage collector and matches keys and values based
   * on <code>==</code> not <code>equals()</code>.
   * <p>
   * <p>
   * When you construct a <code>ReferenceIdentityMap</code>, you can specify what
kind
   * of references are used to store the map's keys and values.
   * If non-hard references are used, then the garbage collector can remove
   * mappings if a key or value becomes unreachable, or if the JVM's memory is
   * running low. For information on how the different reference types behave,
   * see {@link Reference}.
   * <p>
   * Different types of references can be specified for keys and values.
   * The default constructor uses hard keys and soft values, providing a
   * memory-sensitive cache.
   * <p>
   * This map is similar to
   * {@link org.apache.commons.collections.map.ReferenceMap ReferenceMap}.
   * It differs in that keys and values in this class are compared using <code>==</code>.
   * <p>
   * This map will violate the detail of various Map and map view contracts.
   * As a general rule, don't compare this map to other maps.
   * <p>
   * This {@link Map} implementation does <i>not</i> allow null elements.
   * Attempting to add a null key or value to the map will raise a <code>NullPointerException</code>.
   * <p>
   * This implementation is not synchronized.
   * You can use {@link java.util.Collections#synchronizedMap} to 
   * provide synchronized access to a <code>ReferenceIdentityMap</code>.
   * Remember that synchronization will not stop the garbage collecter removing entries.
   * <p>
   * All the available iterators can be reset back to the start by casting to
   * <code>ResettableIterator</code> and calling <code>reset()</code>.
   *
   * @see java.lang.ref.Reference
   * 
   * @since Commons Collections 3.0 (previously in main package v2.1)
   * @version $Revision: 1.1 $ $Date: 2004/04/27 21:37:32 $
   * 
   * @author Stephen Colebourne
   */
  public class ReferenceIdentityMap extends AbstractReferenceMap implements Serializable {
  
      /** Serialization version */
      private static final long serialVersionUID = -1266190134568365852L;
  
      /**
       * Constructs a new <code>ReferenceIdentityMap</code> that will
       * use hard references to keys and soft references to values.
       */
      public ReferenceIdentityMap() {
          super(HARD, SOFT, DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, false);
      }
  
      /**
       * Constructs a new <code>ReferenceIdentityMap</code> that will
       * use the specified types of references.
       *
       * @param keyType  the type of reference to use for keys;
       *   must be {@link #HARD}, {@link #SOFT}, {@link #WEAK}
       * @param valueType  the type of reference to use for values;
       *   must be {@link #HARD}, {@link #SOFT}, {@link #WEAK}
       */
      public ReferenceIdentityMap(int keyType, int valueType) {
          super(keyType, valueType, DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, false);
      }
  
      /**
       * Constructs a new <code>ReferenceIdentityMap</code> that will
       * use the specified types of references.
       *
       * @param keyType  the type of reference to use for keys;
       *   must be {@link #HARD}, {@link #SOFT}, {@link #WEAK}
       * @param valueType  the type of reference to use for values;
       *   must be {@link #HARD}, {@link #SOFT}, {@link #WEAK}
       * @param purgeValues should the value be automatically purged when the 
       *   key is garbage collected 
       */
      public ReferenceIdentityMap(int keyType, int valueType, boolean purgeValues) {
          super(keyType, valueType, DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, purgeValues);
      }
  
      /**
       * Constructs a new <code>ReferenceIdentityMap</code> with the
       * specified reference types, load factor and initial capacity.
       *
       * @param keyType  the type of reference to use for keys;
       *   must be {@link #HARD}, {@link #SOFT}, {@link #WEAK}
       * @param valueType  the type of reference to use for values;
       *   must be {@link #HARD}, {@link #SOFT}, {@link #WEAK}
       * @param capacity  the initial capacity for the map
       * @param loadFactor  the load factor for the map
       */
      public ReferenceIdentityMap(int keyType, int valueType, int capacity, float loadFactor)
{
          super(keyType, valueType, capacity, loadFactor, false);
      }
  
      /**
       * Constructs a new <code>ReferenceIdentityMap</code> with the
       * specified reference types, load factor and initial capacity.
       *
       * @param keyType  the type of reference to use for keys;
       *   must be {@link #HARD}, {@link #SOFT}, {@link #WEAK}
       * @param valueType  the type of reference to use for values;
       *   must be {@link #HARD}, {@link #SOFT}, {@link #WEAK}
       * @param capacity  the initial capacity for the map
       * @param loadFactor  the load factor for the map
       * @param purgeValues  should the value be automatically purged when the 
       *   key is garbage collected 
       */
      public ReferenceIdentityMap(int keyType, int valueType, int capacity,
                          float loadFactor, boolean purgeValues) {
          super(keyType, valueType, capacity, loadFactor, purgeValues);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Gets the hash code for the key specified.
       * <p>
       * This implementation uses the identity hash code.
       * 
       * @param key  the key to get a hash code for
       * @return the hash code
       */
      protected int hash(Object key) {
          return System.identityHashCode(key);
      }
  
      /**
       * Gets the hash code for a MapEntry.
       * <p>
       * This implementation uses the identity hash code.
       * 
       * @param key  the key to get a hash code for, may be null
       * @param value  the value to get a hash code for, may be null
       * @return the hash code, as per the MapEntry specification
       */
      protected int hashEntry(Object key, Object value) {
          return System.identityHashCode(key) ^
                 System.identityHashCode(value);
      }
  
      /**
       * Compares two keys for equals.
       * <p>
       * This implementation converts the key from the entry to a real reference
       * before comparison and uses <code>==</code>.
       * 
       * @param key1  the first key to compare passed in from outside
       * @param key2  the second key extracted from the entry via <code>entry.key</code>
       * @return true if equal by identity
       */
      protected boolean isEqualKey(Object key1, Object key2) {
          key2 = (keyType > HARD ? ((Reference) key2).get() : key2);
          return (key1 == key2);
      }
  
      /**
       * Compares two values for equals.
       * <p>
       * This implementation uses <code>==</code>.
       * 
       * @param value1  the first value to compare passed in from outside
       * @param value2  the second value extracted from the entry via <code>getValue()</code>
       * @return true if equal by identity
       */
      protected boolean isEqualValue(Object value1, Object value2) {
          return (value1 == value2);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Write the map out using a custom routine.
       */
      private void writeObject(ObjectOutputStream out) throws IOException {
          out.defaultWriteObject();
          doWriteObject(out);
      }
  
      /**
       * Read the map in using a custom routine.
       */
      private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException
{
          in.defaultReadObject();
          doReadObject(in);
      }
  
  }
  
  
  

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