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Add IdentityMap implementation for reference comparisons 

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@131387 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Stephen Colebourne 2003-12-02 21:57:08 +00:00
parent 145e6c8a33
commit b67ef9b935
3 changed files with 357 additions and 4 deletions
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198
src/java/org/apache/commons/collections/map/IdentityMap.java Normal file
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@ -0,0 +1,198 @@
/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/map/IdentityMap.java,v 1.1 2003/12/02 21:57:08 scolebourne Exp $
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001-2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowledgement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.commons.collections.map;
import java.util.Map;
/**
* A <code>Map</code> implementation that matches keys and values based
* on <code>==</code> not <code>equals()</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.
*
* @since Commons Collections 3.0
* @version $Revision: 1.1 $ $Date: 2003/12/02 21:57:08 $
*
* @author java util HashMap
* @author Stephen Colebourne
*/
public class IdentityMap extends HashedMap {
/** Serialisation version */
/**
* Constructs a new empty map with default size and load factor.
*/
public IdentityMap() {
super();
}
/**
* Constructs a new, empty map with the specified initial capacity.
*
* @param initialCapacity the initial capacity
* @throws IllegalArgumentException if the initial capacity is less than one
*/
public IdentityMap(int initialCapacity) {
super(initialCapacity);
}
/**
* Constructs a new, empty map with the specified initial capacity and
* load factor.
*
* @param initialCapacity the initial capacity
* @param loadFactor the load factor
* @throws IllegalArgumentException if the initial capacity is less than one
* @throws IllegalArgumentException if the load factor is less than one
*/
public IdentityMap(int initialCapacity, float loadFactor) {
super(initialCapacity, loadFactor);
}
/**
* Constructor copying elements from another map.
*
* @param map the map to copy
* @throws NullPointerException if the map is null
*/
public IdentityMap(Map map) {
super(map);
}
//-----------------------------------------------------------------------
/**
* Gets the hash code for the key specified.
* 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);
}
/**
* Compares two keys for equals.
* This implementation uses <code>==</code>.
*
* @param key1 the first key to compare
* @param key2 the second key to compare
* @return true if equal by identity
*/
protected boolean isEqualKey(Object key1, Object key2) {
return (key1 == key2);
}
/**
* Compares two values for equals.
* This implementation uses <code>==</code>.
*
* @param value1 the first value to compare
* @param value2 the second value to compare
* @return true if equal by identity
*/
protected boolean isEqualValue(Object value1, Object value2) {
return (value1 == value2);
}
/**
* Creates an entry to store the data.
* This implementation creates an IdentityEntry instance.
*
* @param next the next entry in sequence
* @param hashCode the hash code to use
* @param key the key to store
* @param value the value to store
* @return the newly created entry
*/
protected HashEntry createEntry(HashEntry next, int hashCode, Object key, Object value) {
return new IdentityEntry(next, hashCode, key, value);
}
//-----------------------------------------------------------------------
/**
* HashEntry
*/
protected static class IdentityEntry extends HashEntry {
protected IdentityEntry(HashEntry next, int hashCode, Object key, Object value) {
super(next, hashCode, key, value);
}
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (obj instanceof Map.Entry == false) {
return false;
}
Map.Entry other = (Map.Entry) obj;
return
(getKey() == other.getKey()) &&
(getValue() == other.getValue());
}
public int hashCode() {
return System.identityHashCode(getKey()) ^
System.identityHashCode(getValue());
}
}
}

8
src/test/org/apache/commons/collections/map/TestAll.java
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@ -1,5 +1,5 @@
/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/test/org/apache/commons/collections/map/TestAll.java,v 1.5 2003/12/02 00:44:13 scolebourne Exp $
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/test/org/apache/commons/collections/map/TestAll.java,v 1.6 2003/12/02 21:57:08 scolebourne Exp $
* ====================================================================
*
* The Apache Software License, Version 1.1
@ -65,7 +65,7 @@ import junit.framework.TestSuite;
* Entry point for tests.
*
* @since Commons Collections 3.0
* @version $Revision: 1.5 $ $Date: 2003/12/02 00:44:13 $
* @version $Revision: 1.6 $ $Date: 2003/12/02 21:57:08 $
*
* @author Stephen Colebourne
*/
@ -86,8 +86,8 @@ public class TestAll extends TestCase {
suite.addTest(TestFixedSizeMap.suite());
suite.addTest(TestFixedSizeSortedMap.suite());
suite.addTest(TestFlat3Map.suite());
// suite.addTest(TestHashedMap.suite());
// suite.addTest(TestIdentityMap.suite());
suite.addTest(TestHashedMap.suite());
suite.addTest(TestIdentityMap.suite());
suite.addTest(TestLazyMap.suite());
suite.addTest(TestLazySortedMap.suite());
suite.addTest(TestListOrderedMap.suite());

155
src/test/org/apache/commons/collections/map/TestIdentityMap.java Normal file
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/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/test/org/apache/commons/collections/map/TestIdentityMap.java,v 1.1 2003/12/02 21:57:08 scolebourne Exp $
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001-2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowledgement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.commons.collections.map;
import java.util.Iterator;
import java.util.Map;
import junit.framework.Test;
import junit.framework.TestSuite;
import junit.textui.TestRunner;
import org.apache.commons.collections.AMap;
import org.apache.commons.collections.AbstractTestObject;
/**
* JUnit tests.
*
* @version $Revision: 1.1 $ $Date: 2003/12/02 21:57:08 $
*
* @author Stephen Colebourne
*/
public class TestIdentityMap extends AbstractTestObject {
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 TestIdentityMap(String testName) {
super(testName);
}
public static void main(String[] args) {
TestRunner.run(suite());
}
public static Test suite() {
return new TestSuite(TestIdentityMap.class);
// return BulkTest.makeSuite(TestIdentityMap.class); // causes race condition!
}
public Object makeObject() {
return new IdentityMap();
}
public String getCompatibilityVersion() {
return "3";
}
//-----------------------------------------------------------------------
public void testBasics() {
AMap map = new IdentityMap();
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() {
AMap map = new IdentityMap();
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));
}
}