Java Collection First getFirst(Collection collection)

Description

get First

License

Apache License

Declaration

public static <T> T getFirst(Collection<T> collection) 

Method Source Code

//package com.java2s;
/**/*from   w  w w  .  j  a v  a2 s . c  o m*/
 * Copyright (c) 2005-2012 springside.org.cn
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 */

import java.util.Collection;

import java.util.Map;

public class Main {

    public static <T> T getFirst(Collection<T> collection) {
        if (isEmpty(collection)) {
            return null;
        }

        return collection.iterator().next();
    }

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

    /**
     * <p>Checks if an array of Objects is empty or <code>null</code>.</p>
     *
     * @param array  the array to test
     * @return <code>true</code> if the array is empty or <code>null</code>
     * @since 2.1
     */
    public static boolean isEmpty(Object[] array) {
        if (array == null || array.length == 0) {
            return true;
        }
        return false;
    }

    /**
     * <p>Checks if an array of primitive longs is empty or <code>null</code>.</p>
     *
     * @param array  the array to test
     * @return <code>true</code> if the array is empty or <code>null</code>
     * @since 2.1
     */
    public static boolean isEmpty(long[] array) {
        if (array == null || array.length == 0) {
            return true;
        }
        return false;
    }

    /**
     * <p>Checks if an array of primitive ints is empty or <code>null</code>.</p>
     *
     * @param array  the array to test
     * @return <code>true</code> if the array is empty or <code>null</code>
     * @since 2.1
     */
    public static boolean isEmpty(int[] array) {
        if (array == null || array.length == 0) {
            return true;
        }
        return false;
    }

    /**
     * <p>Checks if an array of primitive shorts is empty or <code>null</code>.</p>
     *
     * @param array  the array to test
     * @return <code>true</code> if the array is empty or <code>null</code>
     * @since 2.1
     */
    public static boolean isEmpty(short[] array) {
        if (array == null || array.length == 0) {
            return true;
        }
        return false;
    }

    /**
     * <p>Checks if an array of primitive chars is empty or <code>null</code>.</p>
     *
     * @param array  the array to test
     * @return <code>true</code> if the array is empty or <code>null</code>
     * @since 2.1
     */
    public static boolean isEmpty(char[] array) {
        if (array == null || array.length == 0) {
            return true;
        }
        return false;
    }

    /**
     * <p>Checks if an array of primitive bytes is empty or <code>null</code>.</p>
     *
     * @param array  the array to test
     * @return <code>true</code> if the array is empty or <code>null</code>
     * @since 2.1
     */
    public static boolean isEmpty(byte[] array) {
        if (array == null || array.length == 0) {
            return true;
        }
        return false;
    }

    /**
     * <p>Checks if an array of primitive doubles is empty or <code>null</code>.</p>
     *
     * @param array  the array to test
     * @return <code>true</code> if the array is empty or <code>null</code>
     * @since 2.1
     */
    public static boolean isEmpty(double[] array) {
        if (array == null || array.length == 0) {
            return true;
        }
        return false;
    }

    /**
     * <p>Checks if an array of primitive floats is empty or <code>null</code>.</p>
     *
     * @param array  the array to test
     * @return <code>true</code> if the array is empty or <code>null</code>
     * @since 2.1
     */
    public static boolean isEmpty(float[] array) {
        if (array == null || array.length == 0) {
            return true;
        }
        return false;
    }

    /**
     * <p>Checks if an array of primitive booleans is empty or <code>null</code>.</p>
     *
     * @param array  the array to test
     * @return <code>true</code> if the array is empty or <code>null</code>
     * @since 2.1
     */
    public static boolean isEmpty(boolean[] array) {
        if (array == null || array.length == 0) {
            return true;
        }
        return false;
    }

    public static boolean isEmpty(Map map) {
        if (map == null || map.size() == 0) {
            return true;
        }
        return false;
    }
}

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