Java Map Merge mergeIfAbsent(Map map, Map toMerge)

Description

Add all values of a map to another map, but onlfy if not already existing.

License

Apache License

Parameter

Parameter	Description
map	target map
toMerge	the values to ad

Declaration

public static void mergeIfAbsent(Map<String, String> map, Map<String, String> toMerge) 

Method Source Code

//package com.java2s;
/*//from   w  ww.j a va 2s .  c  om
 * Copyright 2016 Red Hat, Inc.
 *
 * Red Hat 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.Map;

public class Main {
    /**
     * Add all values of a map to another map, but onlfy if not already existing.
     * @param map target map
     * @param toMerge the values to ad
     */
    public static void mergeIfAbsent(Map<String, String> map, Map<String, String> toMerge) {
        for (Map.Entry<String, String> entry : toMerge.entrySet()) {
            putIfAbsent(map, entry.getKey(), entry.getValue());
            ;
        }
    }

    /**
     * Adds the given key and value pair into the map if the map does not already contain a value for that key
     */
    public static void putIfAbsent(Map<String, String> map, String name, String value) {
        if (!map.containsKey(name)) {
            map.put(name, value);
        }
    }
}

Related

1. mergeEntries( Map dest, Iterable> entries)
2. mergeEnv(Map newEnv, Map env)
3. mergeEnvironmentVariables(Map environmentSource, Map environmentDestination, String environmentVariable)
4. mergeFamilies(Map familySource, Map familyTarget)
5. mergeFixedValueConditions(Map> left, Map> right)
6. mergeImportedPermissionsWithExistingPermissions( Map> existingRoleIdsToActionIds, Map importedRoleIdsToActionIds)
7. mergeListWithMap(List from, Map to)
8. mergeMap(Map map, Object[]... pairs)
9. mergeMap(Map primaryValues, Map defaultValues)