Java List Move Item moveElementToIndex( List list, ELEMENT fromElement, ELEMENT toElement)

Description

move Element To Index

License

Apache License

Declaration

public static <ELEMENT> List<ELEMENT> moveElementToIndex(
            List<ELEMENT> list, ELEMENT fromElement, ELEMENT toElement) 

Method Source Code

//package com.java2s;
/*/*from  w  w  w  .j a v  a 2 s  .  c  om*/
 * Copyright 2014-2015 the original author or authors.
 *
 * 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.ArrayList;

import java.util.List;

public class Main {
    public static <ELEMENT> List<ELEMENT> moveElementToIndex(
            List<ELEMENT> list, ELEMENT fromElement, ELEMENT toElement) {
        assertObjectNotNull("list", list);
        final int fromIndex = list.indexOf(fromElement);
        final int toIndex = list.indexOf(toElement);
        return moveElementToIndex(list, fromIndex, toIndex);
    }

    public static <ELEMENT> List<ELEMENT> moveElementToIndex(
            List<ELEMENT> list, int fromIndex, int toIndex) {
        assertObjectNotNull("list", list);
        if (fromIndex == toIndex) {
            String msg = "The argument 'fromIndex' and 'toIndex' should not be same:";
            msg = msg + " fromIndex=" + fromIndex + " toIndex" + toIndex;
            throw new IllegalArgumentException(msg);
        }
        if (fromIndex < 0 || toIndex < 0) {
            String msg = "The argument 'fromIndex' and 'toIndex' should not be minus:";
            msg = msg + " fromIndex=" + fromIndex + " toIndex" + toIndex;
            throw new IllegalArgumentException(msg);
        }
        final boolean fromLess = fromIndex < toIndex;
        final List<ELEMENT> movedList = new ArrayList<ELEMENT>();
        final int firstIndex = fromLess ? fromIndex : toIndex;
        final int secondIndex = !fromLess ? fromIndex : toIndex;
        final List<ELEMENT> first = list.subList(0, firstIndex);
        final ELEMENT element = list.get(fromIndex);
        final int adjustmentIndex = fromLess ? 1 : 0;
        final List<ELEMENT> middle = list.subList(firstIndex
                + adjustmentIndex, secondIndex + adjustmentIndex);
        final List<ELEMENT> last = list.subList(secondIndex + 1,
                list.size());
        movedList.addAll(first);
        if (!fromLess) {
            movedList.add(element);
        }
        movedList.addAll(middle);
        if (fromLess) {
            movedList.add(element);
        }
        movedList.addAll(last);
        return movedList;
    }

    protected static void assertObjectNotNull(String variableName,
            Object value) {
        if (variableName == null) {
            String msg = "The value should not be null: variableName=null value="
                    + value;
            throw new IllegalArgumentException(msg);
        }
        if (value == null) {
            String msg = "The value should not be null: variableName="
                    + variableName;
            throw new IllegalArgumentException(msg);
        }
    }
}

Related

1. moveBackward(final List list, final int[] indices)
2. moveBefore(List list, T element, T referenceElement)
3. moved(List old, List nu, Collection added, Collection removed)
4. moveDownItems(List list, int[] positions)
5. moveElementInList(List