org.apache.mina.util.MapBackedSet Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.mina.util;
import java.io.Serializable;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
/**
* A {@link Map}-backed {@link Set}.
*
* @param The element stored in the set
*
* @author Apache MINA Project
*/
public class MapBackedSet extends AbstractSet implements Serializable {
private static final long serialVersionUID = -8347878570391674042L;
protected final Map map;
/**
* Creates a new MapBackedSet instance
*
* @param map The map that we want to back
*/
public MapBackedSet(Map map) {
this.map = map;
}
/**
* Creates a new MapBackedSet instance
*
* @param map The map that we want to back
* @param c The elements we want to add in the map
*/
public MapBackedSet(Map map, Collection c) {
this.map = map;
addAll(c);
}
/**
* {@inheritDoc}
*/
@Override
public int size() {
return map.size();
}
/**
* {@inheritDoc}
*/
@Override
public boolean contains(Object o) {
return map.containsKey(o);
}
/**
* {@inheritDoc}
*/
@Override
public Iterator iterator() {
return map.keySet().iterator();
}
/**
* {@inheritDoc}
*/
@Override
public boolean add(E o) {
return map.put(o, Boolean.TRUE) == null;
}
/**
* {@inheritDoc}
*/
@Override
public boolean remove(Object o) {
return map.remove(o) != null;
}
/**
* {@inheritDoc}
*/
@Override
public void clear() {
map.clear();
}
}