Java Random Element randomEles(List list, int count)

Description

random Eles

License

Apache License

Declaration

public static <T> List<T> randomEles(List<T> list, int count) 

Method Source Code

//package com.java2s;
/*/*from ww w.j  ava 2 s  .c  om*/
 * 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;
import java.util.Random;

public class Main {
    private static Random random = new Random();

    public static <T> List<T> randomEles(List<T> list, int count) {
        final List<T> result = new ArrayList<T>(count);
        int limit = list.size();
        while (--count > 0) {
            result.add(randomEle(list, limit));
        }

        return result;
    }

    public static <T> T randomEle(List<T> list) {
        return randomEle(list, list.size());
    }

    public static <T> T randomEle(List<T> list, int limit) {
        return list.get(randomInt(limit));
    }

    public static int randomInt(int min, int max) {
        return random.nextInt(max - min) + min;
    }

    public static int randomInt() {
        return random.nextInt();
    }

    public static int randomInt(int limit) {
        return random.nextInt(limit);
    }
}

Related

1. randomElement(List list)
2. randomElement(T... values)
3. randomElement(T[] array)
4. randomElementOf(final List list)
5. randomElementOf(String[] array)