Mercurial > hg > blitz_stable
view src/com/go/trove/util/NullKeyMap.java @ 32:243c74d599bf
Update ignores
author | Dan Creswell <dan.creswell@gmail.com> |
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date | Sat, 12 Jun 2010 10:41:47 +0100 |
parents | 3dc0c5604566 |
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/* ==================================================================== * Trove - Copyright (c) 1997-2000 Walt Disney Internet Group * ==================================================================== * The Tea Software License, Version 1.1 * * Copyright (c) 2000 Walt Disney Internet Group. 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 acknowledgment: * "This product includes software developed by the * Walt Disney Internet Group (http://opensource.go.com/)." * Alternately, this acknowledgment may appear in the software itself, * if and wherever such third-party acknowledgments normally appear. * * 4. The names "Tea", "TeaServlet", "Kettle", "Trove" and "BeanDoc" must * not be used to endorse or promote products derived from this * software without prior written permission. For written * permission, please contact opensource@dig.com. * * 5. Products derived from this software may not be called "Tea", * "TeaServlet", "Kettle" or "Trove", nor may "Tea", "TeaServlet", * "Kettle", "Trove" or "BeanDoc" appear in their name, without prior * written permission of the Walt Disney Internet Group. * * 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 WALT DISNEY INTERNET GROUP 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. * ==================================================================== * * For more information about Tea, please see http://opensource.go.com/. */ package com.go.trove.util; import java.util.*; import java.io.Serializable; /****************************************************************************** * A Map supporting null keys that wraps a Map that doesn't support null keys. * NullKeyMap substitutes null keys with a special placeholder object. This * technique does not work when the wrapped Map is a TreeMap because it cannot * be compared against other objects. In order for TreeMaps to support null * keys, use any of the null ordering comparators found in the {@link Utils} * class. * * @author Brian S O'Neill * @version * <!--$$Revision: 1.1 $-->, <!--$$JustDate:--> 9/07/00 <!-- $--> */ public class NullKeyMap extends AbstractMap implements Serializable { // Instead of using null as a key, use this placeholder. private static final Object NULL = new Serializable() {}; private Map mMap; private transient Set mKeySet; private transient Set mEntrySet; /** * @param map The map to wrap. */ public NullKeyMap(Map map) { mMap = map; } public int size() { return mMap.size(); } public boolean isEmpty() { return mMap.isEmpty(); } public boolean containsKey(Object key) { return (key == null) ? mMap.containsKey(NULL) : mMap.containsKey(key); } public boolean containsValue(Object value) { return mMap.containsValue(value); } public Object get(Object key) { return (key == null) ? mMap.get(NULL) : mMap.get(key); } public Object put(Object key, Object value) { return mMap.put((key == null) ? NULL : key, value); } public Object remove(Object key) { return (key == null) ? mMap.remove(NULL) : mMap.remove(key); } public void putAll(Map map) { Iterator it = map.entrySet().iterator(); while (it.hasNext()) { Map.Entry entry = (Map.Entry)it.next(); put(entry.getKey(), entry.getValue()); } } public void clear() { mMap.clear(); } public Set keySet() { if (mKeySet == null) { mKeySet = new AbstractSet() { public Iterator iterator() { final Iterator it = mMap.keySet().iterator(); return new Iterator() { public boolean hasNext() { return it.hasNext(); } public Object next() { Object key = it.next(); return (key == NULL) ? null : key; } public void remove() { it.remove(); } }; } public boolean contains(Object key) { return containsKey((key == null) ? NULL : key); } public boolean remove(Object key) { if (key == null) { key = NULL; } if (containsKey(key)) { NullKeyMap.this.remove(key); return true; } else { return false; } } public int size() { return NullKeyMap.this.size(); } public void clear() { NullKeyMap.this.clear(); } }; } return mKeySet; } public Collection values() { return mMap.values(); } public Set entrySet() { if (mEntrySet == null) { mEntrySet = new AbstractSet() { public Iterator iterator() { final Iterator it = mMap.entrySet().iterator(); return new Iterator() { public boolean hasNext() { return it.hasNext(); } public Object next() { final Map.Entry entry = (Map.Entry)it.next(); if (entry.getKey() == NULL) { return new AbstractMapEntry() { public Object getKey() { return null; } public Object getValue() { return entry.getValue(); } public Object setValue(Object value) { return entry.setValue(value); } }; } else { return entry; } } public void remove() { it.remove(); } }; } public boolean contains(Object obj) { if (!(obj instanceof Map.Entry)) { return false; } Map.Entry entry = (Map.Entry)obj; Object key = entry.getKey(); Object value = entry.getValue(); if (key == null) { key = NULL; } Object lookup = get(key); if (lookup == null) { return value == null; } else { return lookup.equals(value); } } public boolean remove(Object obj) { if (!(obj instanceof Map.Entry)) { return false; } Map.Entry entry = ((Map.Entry)obj); Object key = entry.getKey(); if (key == null) { key = NULL; } if (containsKey(key)) { NullKeyMap.this.remove(key); return true; } else { return false; } } public int size() { return NullKeyMap.this.size(); } public void clear() { NullKeyMap.this.clear(); } }; } return mEntrySet; } }