CollectionUtils.java

/**
 * MIT License
 *
 * Copyright (c) 2017 zgqq
 *
 * 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.
 */
package mah.common.util;

import java.util.Collection;
import java.util.Collections;
import java.util.List;

/**
 * Created by zgq on 2017-01-11 20:20
 */
public final class CollectionUtils {

    private CollectionUtils() {}

    public static boolean isNotEmpty(Collection<?> collection) {
        return collection != null && !collection.isEmpty();
    }

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

    public static <T> List<T> subList(List<T> list, int len) {
        if (list == null) {
            throw new NullPointerException();
        }
        if (list.isEmpty()) {
            return list;
        }
        if (len == 0 || list.size() < len) {
            return list.subList(0, list.size() - 1);
        }
        return list.subList(0, len - 1);
    }

    public static int getSize(List<?> list, int len) {
        return list.size() > len ? len : list.size();
    }
}