/***************************************************************************
* Copyright (C) 2011 by Fabrizio Montesi <famontesi@gmail.com> *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU Library General Public License as *
* published by the Free Software Foundation; either version 2 of the *
* License, 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 Library General Public *
* License along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
* *
* For details about the authors of this software, see the AUTHORS file. *
***************************************************************************/
package jolie.util;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
/**
*
* @author Fabrizio Montesi
*/
public abstract class MultiMap< K, V >
{
private final Map< K, Collection< V > > map = new HashMap< K, Collection< V > >();
protected abstract Collection< V > createCollection();
public boolean containsKey( K key )
{
return map.containsKey( key );
}
public Collection< V > get( K key )
{
Collection< V > r = map.get( key );
if ( r == null ) {
return Collections.emptyList();
}
return r;
}
public V put( K key, V value )
{
Collection< V > r = map.get( key );
if ( r == null ) {
r = createCollection();
map.put( key, r );
}
r.add( value );
return value;
}
public void clear()
{
map.clear();
}
public Set< K > keySet()
{
return map.keySet();
}
}