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 * Version: CPL 1.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Common Public
 * License Version 1.0 (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.eclipse.org/legal/cpl-v10.html
 *
 * Software distributed under the License is distributed on an "AS
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package org.jruby.util.collections;

import java.util.*;

/**
 * A simple set that uses weak references to ensure that its elements can be garbage collected.
 * See WeakHashMap.
 *
 * @author Robert Egglestone
 */
public class WeakHashSet implements Set {
    private WeakHashMap map;

    public WeakHashSet() {
        map = new WeakHashMap();
    }

    public WeakHashSet(int size) {
        map = new WeakHashMap(size);
    }

    public boolean add(T o) {
        Object previousValue = map.put(o, null);
        return previousValue == null;
    }

    public Iterator iterator() {
        return map.keySet().iterator();
    }

    public int size() {
        return map.size();
    }

    public boolean isEmpty() {
        return map.isEmpty();
    }

    public boolean contains(Object o) {
        return map.containsKey(o);
    }

    public boolean remove(Object o) {
        boolean contains = contains(o);
        map.remove(o);
        return contains;
    }

    public boolean removeAll(Collection collection) {
        return map.keySet().removeAll(collection);
    }

    public boolean retainAll(Collection collection) {
        return map.keySet().retainAll(collection);
    }

    public void clear() {
        map.clear();
    }

    public Object[] toArray() {
        return map.keySet().toArray();
    }

    public boolean containsAll(Collection arg0) {
        return map.keySet().containsAll(arg0);
    }

    public boolean addAll(Collection arg0) {
        boolean added = false;
        for (T i: arg0) {
            add(i);
            added = true;
        }
        return added;
    }

    public  T[] toArray(T[] arg0) {
        return map.keySet().toArray(arg0);
    }

}