Java List First Item first(List list)

Description

first

License

Apache License

Declaration

public static <K> K first(List<K> list) 

Method Source Code

//package com.java2s;
/*// ww w . ja va  2s . co  m
 * Copyright (c) 2008-2016 Computer Network Information Center (CNIC), Chinese Academy of Sciences.
 * 
 * This file is part of Duckling 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.List;
import java.util.Map;

public class Main {

    public static <K> K first(List<K> list) {
        if (isNull(list)) {
            return null;
        }
        return list.get(0);
    }

    public static boolean isNull(String[] array) {
        return (array == null || array.length == 0 || (array.length == 1 && "".equals(array[0])));
    }

    public static boolean isNull(int[] array) {
        return (array == null || array.length == 0);
    }

    public static boolean isNull(List<?> list) {
        return (list == null) || (list.size() == 0);
    }

    public static boolean isNull(Map<?, ?> map) {
        return (map == null || (map.isEmpty()));
    }

    public static boolean isNull(String str) {
        return str == null || "".equals(str.trim()) || "null".equals(str.toLowerCase().trim());
    }
}

Related

1. expectedOrder(List src, Object first, Object second)
2. extractFirst(int numberToExtract, List list)
3. first(final List list)
4. first(final List list, final int oridinal)
5. first(final List t)
6. first(List l)
7. first(List l)
8. first(List list)
9. first(List list)