Gets a value from a map of maps. - Java java.util

Java examples for java.util:Map Value

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Description

Gets a value from a map of maps.

Demo Code

/*//from   w w w.j  av a 2  s. co  m
 * Copyright 2013 Anton Karmanov
 *
 * 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 com.java2s;

import java.util.Map;

public class Main {
    /**
     * Gets a value from a map of maps.
     * 
     * @param map1 the map of maps.
     * @param key1 the key for the map of maps.
     * @param key2 the key for a nested map.
     * @return the value, or <code>null</code> if the key is not found neither in the outer,
     * nor in the nested map.
     */
    static <K1, K2, V> V getFromMapMap(Map<K1, Map<K2, V>> map1, K1 key1,
            K2 key2) {
        Map<K2, V> map2 = map1.get(key1);
        return map2 == null ? null : map2.get(key2);
    }
}

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