Java ConcurrentMap addConcurrent(K key, C values, ConcurrentMap map)

Description

If map already has a value associated with the key it adds values to that value, otherwise it will put values to the map.

License

Apache License

Parameter

Parameter	Description
key	Key under which we are adding values
values	Values we want to add
map	Map which we are adding values to
K	Key
V	Value
C	Collection

Return

New value associated with the key

Declaration

public static <K, V, C extends Collection<V>> C addConcurrent(K key, C values, ConcurrentMap<K, C> map) 

Method Source Code

//package com.java2s;
/*//from  ww  w  .ja v  a  2s.  c  om
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

import java.util.Collection;

import java.util.concurrent.ConcurrentMap;

public class Main {
    /**
     * If map already has a value associated with the key it adds values to that
     * value, otherwise it will put values to the map.  Do not reuse values.
     *
     * @param key    Key under which we are adding values
     * @param values Values we want to add
     * @param map    Map which we are adding values to
     * @param <K> Key
     * @param <V> Value
     * @param <C> Collection
     * @return New value associated with the key
     */
    public static <K, V, C extends Collection<V>> C addConcurrent(K key, C values, ConcurrentMap<K, C> map) {
        C currentValues = map.get(key);
        if (currentValues == null) {
            currentValues = map.putIfAbsent(key, values);
            if (currentValues == null) {
                return values;
            }
        }
        synchronized (currentValues) {
            currentValues.addAll(values);
        }
        return currentValues;
    }
}

Related

1. addClassMapping(String className, Class clazz)
2. addIfAbsent(K key, ConcurrentMap map, Object value)
3. clearClassMapping()
4. clearDefaultResourceBundles()
5. create(boolean sorted)