Mega Code Archive
Multi Map
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/*
* FindBugs - Find Bugs in Java programs
* Copyright (C) 2006, University of Maryland
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* @author pugh
*/
public class MultiMap<K, V> {
final Class<? extends Collection<V>> containerClass;
@SuppressWarnings("unchecked")
public MultiMap(Class<? extends Collection> c) {
containerClass = (Class<? extends Collection<V>>) c;
}
private Collection<V> makeCollection() {
try {
return containerClass.newInstance();
} catch (InstantiationException e) {
throw new RuntimeException(e);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
}
}
Map<K, Collection<V>> map = new HashMap<K, Collection<V>>();
public Collection<? extends K> keySet() {
return map.keySet();
}
public void clear() {
map.clear();
}
public void add(K k, V v) {
Collection<V> s = map.get(k);
if (s == null) {
s = makeCollection();
map.put(k, s);
}
s.add(v);
}
public void remove(K k, V v) {
Collection<V> s = map.get(k);
if (s != null) {
s.remove(v);
if (s.isEmpty()) map.remove(k);
}
}
public void removeAll(K k) {
map.remove(k);
}
public Collection<V> get(K k) {
Collection<V> s = map.get(k);
if (s != null) return s;
return Collections.<V>emptySet();
}
}
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