Java Map Invert invert(Map map)

Description

invert

License

Apache License

Declaration

public static <T, U> Map<U, T> invert(Map<T, U> map) 

Method Source Code

//package com.java2s;
/*//from   ww w.  j  a  v  a  2 s.  co  m
 * Copyright Terracotta, Inc.
 *
 * 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.
 */

import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import static java.util.Collections.unmodifiableMap;

public class Main {
    public static <T, U> Map<U, T> invert(Map<T, U> map) {
        Map<U, T> inversion = new HashMap<U, T>();
        for (Entry<T, U> e : map.entrySet()) {
            if (inversion.put(e.getValue(), e.getKey()) != null) {
                throw new IllegalArgumentException("Inversion is not a valid map");
            }
        }
        return unmodifiableMap(inversion);
    }
}

Related

1. inverseGet(Map map, Object value)
2. invert(Map map)
3. invert(Map in)
4. invert(Map map)
5. invert(Map map, String prefix)
6. invertedMapFrom(Map source)
7. invertMap(final Map map)
8. invertMap(final Map map)
9. invertMap(Map map)