Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*-------------------------------------------------------------------------+
 |                                                                          |
 | Copyright 2005-2011 The ConQAT Project                                   |
 |                                                                          |
 | 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.Collection;

import java.util.HashSet;

import java.util.Set;

public class Main {
    /**
     * Returns the set-theoretic difference between the first and the additional
     * collections, i.e. a set containing all elements that occur in the first,
     * but not in any of the other collections. We use a {@link HashSet}, so the
     * elements should support hashing.
     */
    @SafeVarargs
    public static <T> HashSet<T> differenceSet(Collection<T> collection1, Collection<T>... furtherCollections) {
        HashSet<T> result = new HashSet<T>(collection1);
        for (Collection<T> collection : furtherCollections) {
            if (collection instanceof Set) {
                result.removeAll(collection);
            } else {
                // if the collection is not already a set, it will be
                // significantly faster to first build a set, to speed up the
                // containment query in the following call.
                result.removeAll(new HashSet<T>(collection));
            }
        }
        return result;
    }
}