001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *        http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 */
019
020package org.apache.isis.core.commons.lang;
021
022import java.util.Collections;
023import java.util.HashMap;
024import java.util.Map;
025
026public final class MapUtil {
027
028    private MapUtil() {
029    }
030
031    /**
032     * Converts a list of objects [a, 1, b, 2] into a map {a -> 1; b -> 2}
033     */
034    @SuppressWarnings("unchecked")
035    public static <K,V> Map<K,V> asMap(Object... keyValPair){
036        Map<K,V> map = new HashMap<K,V>();
037
038        if(keyValPair.length % 2 != 0){
039            throw new IllegalArgumentException("Keys and values must be pairs.");
040        }
041
042        for(int i = 0; i < keyValPair.length; i += 2){
043            map.put((K) keyValPair[i], (V) keyValPair[i+1]);
044        }
045
046        return Collections.unmodifiableMap(map);
047    }
048}