/* SimpleMap Copyright (C) 1999 Jochen Hoenicke.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id$
 */

package jode.util;
///#def COLLECTIONS java.util
import java.util.AbstractMap;
import java.util.Map;
import java.util.Iterator;
import java.util.Set;
///#enddef

/**
 * This is a very simple map, using a set as backing.  
 * The default backing set is a simple set, but you can specify any other
 * set of Map.Entry in the constructor.
 */
public class SimpleMap extends AbstractMap {
    private Set backing;

    public SimpleMap() {
	backing = new SimpleSet();
    }
    
    public SimpleMap(int initialCapacity) {
	backing = new SimpleSet(initialCapacity);
    }

    public SimpleMap(Set fromSet) {
	backing = fromSet;
    }
	
    public Set entrySet() {
	return backing;
    }

    public static class SimpleEntry implements Map.Entry {
	Object key;
	Object value;

	public SimpleEntry(Object key, Object value) {
	    this.key = key;
	    this.value = value;
	}

	public Object getKey() {
	    return key;
	}

	public Object getValue() {
	    return value;
	}

	public Object setValue(Object newValue) {
	    Object old = value;
	    value = newValue;
	    return old;
	}
	
	public int hashCode() {
	    return key.hashCode() ^ value.hashCode();
	}

	public boolean equals(Object o) {
	    if (o instanceof Map.Entry) {
		Map.Entry e = (Map.Entry) o;
		return key.equals(e.getKey()) && value.equals(e.getValue());
	    }
	    return false;
	}
    }

    public Object put(Object key, Object value) {
	for (Iterator i = backing.iterator();
	     i.hasNext(); ) {
	    Map.Entry entry = (Map.Entry) i.next();
	    if (key.equals(entry.getKey()))
		return entry.setValue(value);
	}
	backing.add(new SimpleEntry(key, value));
	return null;
    }
}