// Copyright 2017 JanusGraph Authors
//
// Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package org.janusgraph.util.datastructures;
import java.util.concurrent.ConcurrentMap;
/**
* Utility class for Maps
*
* @author Matthias Broecheler (me@matthiasb.com)
*/
public class Maps {
public final static <K, V> V putIfAbsent(ConcurrentMap<K, V> map, K key, Factory<V> factory) {
V res = map.get(key);
if (res != null) return res;
else {
V newobj = factory.create();
res = map.putIfAbsent(key, newobj);
if (res == null) return newobj;
else return res;
}
}
}