Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

public class Main {
    /**
     * capitalize first letter
     *
     * <pre>
     * capitalizeFirstLetter(null)     =   null;
     * capitalizeFirstLetter("")       =   "";
     * capitalizeFirstLetter("2ab")    =   "2ab"
     * capitalizeFirstLetter("a")      =   "A"
     * capitalizeFirstLetter("ab")     =   "Ab"
     * capitalizeFirstLetter("Abc")    =   "Abc"
     * </pre>
     *
     * @param str
     * @return
     */
    public static String capitalizeFirstLetter(String str) {
        if (isEmpty(str)) {
            return str;
        }

        char c = str.charAt(0);
        return (!Character.isLetter(c) || Character.isUpperCase(c)) ? str
                : new StringBuilder(str.length()).append(Character.toUpperCase(c)).append(str.substring(1))
                        .toString();
    }

    /**
     * is null or its length is 0
     *
     * <pre>
     * isEmpty(null) = true;
     * isEmpty(&quot;&quot;) = true;
     * isEmpty(&quot;  &quot;) = false;
     * </pre>
     *
     * @param str
     * @return if string is null or its size is 0, return true, else return false.
     */
    public static boolean isEmpty(CharSequence str) {
        return (str == null || str.length() == 0);
    }

    /**
     * get length of CharSequence
     *
     * <pre>
     * length(null) = 0;
     * length(\"\") = 0;
     * length(\"abc\") = 3;
     * </pre>
     *
     * @param str
     * @return if str is null or empty, return 0, else return {@link CharSequence#length()}.
     */
    public static int length(CharSequence str) {
        return str == null ? 0 : str.length();
    }
}