Java List Subtract subtract(final List list1, final List list2)

Description

Subtracts all elements in the second list from the first list, placing the results in a new list.

License

Apache License

Parameter

Parameter	Description
list1	the list to subtract from
list2	the list to subtract

Exception

Parameter	Description
NullPointerException	if either list is null

Return

a new list containing the results

Declaration

public static List subtract(final List list1, final List list2) 

Method Source Code

//package com.java2s;
/*/*from w w w . ja  v  a 2 s.co m*/
 *  Copyright 2001-2004 The Apache Software Foundation
 *
 *  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.Iterator;
import java.util.List;

public class Main {
    /**
     * Subtracts all elements in the second list from the first list,
     * placing the results in a new list.
     * <p>
     * This differs from {@link List#removeAll(Collection)} in that
     * cardinality is respected; if <Code>list1</Code> contains two
     * occurrences of <Code>null</Code> and <Code>list2</Code> only
     * contains one occurrence, then the returned list will still contain
     * one occurrence.
     *
     * @param list1  the list to subtract from
     * @param list2  the list to subtract
     * @return  a new list containing the results
     * @throws NullPointerException if either list is null
     */
    public static List subtract(final List list1, final List list2) {
        final ArrayList result = new ArrayList(list1);
        final Iterator iterator = list2.iterator();

        while (iterator.hasNext()) {
            result.remove(iterator.next());
        }

        return result;
    }
}

Related

1. subtract(final List list1, final List list2)
2. subtract(final List result, final Object o1, final Object o2)
3. subtract(final String[] input, final String[] list)
4. subtract(List a, List b)