com.twelvemonkeys.util.LinkedSet Maven / Gradle / Ivy
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * 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.
*
* * Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS 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 COPYRIGHT HOLDER OR 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.
*/
package com.twelvemonkeys.util;
import java.io.Serializable;
import java.util.*;
/**
* Generic map and linked list implementation of the {@code Set} interface,
* with predictable iteration order.
*
* Resembles {@code LinkedHashSet} from JDK 1.4+, but is backed by a generic
* {@code LinkedMap}, rather than implementing a particular algoritm.
*
*
* @see LinkedMap
*
* @author Harald Kuhr
* @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/util/LinkedSet.java#1 $
*/
public class LinkedSet extends AbstractSet implements Set, Cloneable, Serializable {
private final static Object DUMMY = new Object();
private final Map map;
public LinkedSet() {
map = new LinkedMap();
}
public LinkedSet(Collection pCollection) {
this();
addAll(pCollection);
}
public boolean addAll(Collection pCollection) {
boolean changed = false;
for (E value : pCollection) {
if (add(value) && !changed) {
changed = true;
}
}
return changed;
}
public boolean add(E pValue) {
return map.put(pValue, DUMMY) == null;
}
public int size() {
return map.size();
}
public Iterator iterator() {
return map.keySet().iterator();
}
}