Java List Combine putCombinedList(Map map, Object key, Object value)

Description

put Combined List

License

Open Source License

Declaration

public static Map putCombinedList(Map map, Object key, Object value) 

Method Source Code

//package com.java2s;
/*/*from ww  w.  j a  v a 2  s. co  m*/
 * Copyright 2012 The Solmix Project
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.gnu.org/licenses/ 
 * or see the FSF site: http://www.fsf.org. 
 */

import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;
import java.util.Map;

public class Main {

    public static Map putCombinedList(Map map, Object key, Object value) {
        if (key == null)
            throw new IllegalArgumentException("putCombinedList passed null key");
        Object existingValue = map.get(key);
        Object combinedList = combineAsLists(existingValue, value);
        if (combinedList != null)
            map.put(key, combinedList);
        return map;
    }

    /**
     * @param one
     * @param two
     * @return
     */
    public static Object combineAsLists(Object one, Object two) {
        if (one == null)
            return two;
        if (two == null) {
            return one;
        } else {
            List combinedList = new ArrayList();
            addAsList(combinedList, one);
            addAsList(combinedList, two);
            return combinedList;
        }
    }

    public static List addAsList(List targetList, Object sourceList) {
        if (sourceList == null)
            return targetList;
        if (!(sourceList instanceof List)) {
            targetList.add(sourceList);
            return targetList;
        } else {
            return addAll(targetList, (List) sourceList);
        }
    }

    public static List addAll(List target, List source) {
        if (source == null)
            return target;
        if (target == null) {
            return null;
        } else {
            Iterator elems = source.iterator();
            return addAll(target, elems);
        }
    }

    public static List addAll(List target, Iterator source) {
        if (source == null)
            return target;
        for (; source.hasNext(); target.add(source.next()))
            ;
        return target;
    }
}

Related

1. combineLists(List a, List b)
2. combineString(List lstInput, String strToken)
3. combineStringList(List sList)
4. combineSubtractArrays(List a1, List a2)
5. getCombinedColumnName(final List columnNames, final boolean sortByName)
6. recursiveCombine(List>> toCombinate, int index)