/*
* FindBugs - Find Bugs in Java programs
* Copyright (C) 2003-2008 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
*/
package edu.umd.cs.findbugs.util;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
/**
* @author pugh
*/
public abstract class MergeMap<K, V> {
public static class MinMap<K, V extends Comparable<? super V>> extends MergeMap<K, V> {
@Override
protected V mergeValues(V oldValue, V newValue) {
if (oldValue.compareTo(newValue) > 0)
return newValue;
return oldValue;
}
}
public static class MaxMap<K, V extends Comparable<? super V>> extends MergeMap<K, V> {
@Override
protected V mergeValues(V oldValue, V newValue) {
if (oldValue.compareTo(newValue) < 0)
return newValue;
return oldValue;
}
}
final Map<K, V> map;
protected abstract V mergeValues(V oldValue, V newValue);
public MergeMap() {
map = new HashMap<K, V>();
}
public MergeMap(Map<K, V> map) {
this.map = map;
}
public V put(K k, V v) {
V currentValue = map.get(k);
if (currentValue == null) {
map.put(k, v);
return v;
}
V result = mergeValues(currentValue, v);
if (currentValue != result)
map.put(k, v);
return result;
}
public V get(K k) {
return map.get(k);
}
public boolean containsKey(K k) {
return map.containsKey(k);
}
public Set<Map.Entry<K, V>> entrySet() {
return map.entrySet();
}
public static void main(String args[]) {
MergeMap<String, Integer> m = new MaxMap<String, Integer>();
m.put("a", 1);
m.put("a", 2);
m.put("b", 2);
m.put("b", 1);
System.out.println(m.entrySet());
}
}
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