package com.google.code.hs4j.network.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}.
*
* @author The Apache MINA Project (dev@mina.apache.org)
* @version $Rev: 597692 $, $Date: 2007-11-23 08:56:32 -0700 (Fri, 23 Nov 2007) $
*/
public class MapBackedSet<E> extends AbstractSet<E> implements Serializable {
private static final long serialVersionUID = -8347878570391674042L;
protected final Map<E, Boolean> map;
public MapBackedSet(Map<E, Boolean> map) {
this.map = map;
}
public MapBackedSet(Map<E, Boolean> map, Collection<E> c) {
this.map = map;
addAll(c);
}
@Override
public int size() {
return map.size();
}
@Override
public boolean contains(Object o) {
return map.containsKey(o);
}
@Override
public Iterator<E> iterator() {
return map.keySet().iterator();
}
@Override
public boolean add(E o) {
return map.put(o, Boolean.TRUE) == null;
}
@Override
public boolean remove(Object o) {
return map.remove(o) != null;
}
@Override
public void clear() {
map.clear();
}
}