Mercurial > hg > blitz_condensed
diff src/com/go/trove/util/NullKeyMap.java @ 0:3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
author | Dan Creswell <dan.creswell@gmail.com> |
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date | Sat, 21 Mar 2009 11:00:06 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/com/go/trove/util/NullKeyMap.java Sat Mar 21 11:00:06 2009 +0000 @@ -0,0 +1,270 @@ +/* ==================================================================== + * 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; + } +}