Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2013 Brien L. Wheeler (brienwheeler@yahoo.com)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

import java.util.Collection;

public class Main {
    /**
     * Enforce that a Collection contains no more than one element and return that element
     * if it exists.
     * 
     * @param collection the Collection to examine
     * @return null if the Collection is null or empty, the Collection's single object if
     *       its size is one, or throw if its size is greater than one.
     * @throws IllegalArgumentException if the Collection contains more than one element
     */
    public static <T> T singleObject(Collection<T> collection) {
        if (collection == null || collection.isEmpty())
            return null;
        if (collection.size() > 1)
            throw new IllegalArgumentException("more than one element in collection");
        return collection.iterator().next();
    }
}