Java Collection Find findCommonElementType(Collection collection)

Description

find Common Element Type

License

Apache License

Declaration

public static Class<?> findCommonElementType(Collection collection) 

Method Source Code

//package com.java2s;
/*/*from w w w.  ja v a 2s .co m*/
 * Copyright 2002-2012 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.*;

public class Main {
    public static Class<?> findCommonElementType(Collection collection) {
        if (isEmpty(collection)) {
            return null;
        }
        Class<?> candidate = null;
        for (Object val : collection) {
            if (val != null) {
                if (candidate == null) {
                    candidate = val.getClass();
                } else if (candidate != val.getClass()) {
                    return null;
                }
            }
        }
        return candidate;
    }

    public static boolean isEmpty(Collection collection) {
        return (collection == null || collection.isEmpty());
    }

    public static boolean isEmpty(Map map) {
        return (map == null || map.isEmpty());
    }
}

Related

1. findClass(String name, Collection availableImports, ClassLoader cl)
2. findCommonElementType(Collection collection)
3. findCommonElementType(Collection collection)
4. findCommonElementType(Collection collection)
5. findMax(Collection vals)