package com.andyadc.scaffold.util;

/**
 * A string utility class that manipulates string.
 *
 * @author andaicheng
 */
public class StringUtil {

    /**
     * <p>Checks if a String is empty ("") or null.</p>
     * <p>
     * <pre>
     * StringUtil.isEmpty(null)      = true
     * StringUtil.isEmpty("")        = true
     * StringUtil.isEmpty(" ")       = false
     * StringUtil.isEmpty("bob")     = false
     * StringUtil.isEmpty("  bob  ") = false
     * </pre>
     *
     * @param str the String to check, may be null
     * @return <code>true</code> if the String is empty or null
     */
    public static boolean isEmpty(String str) {
        return str == null || str.length() == 0;
    }

    public static boolean isNotEmpty(String str) {
        return !isEmpty(str);
    }

    /**
     * <p>Checks if a String is whitespace, empty ("") or null.</p>
     * <p>
     * <pre>
     * StringUtil.isBlank(null)      = true
     * StringUtil.isBlank("")        = true
     * StringUtil.isBlank(" ")       = true
     * StringUtil.isBlank("bob")     = false
     * StringUtil.isBlank("  bob  ") = false
     * </pre>
     *
     * @param str the String to check, may be null
     * @return <code>true</code> if the String is null, empty or whitespace
     */
    public static boolean isBlank(String str) {
        int strLen;
        if (str == null || (strLen = str.length()) == 0) {
            return true;
        }
        for (int i = 0; i < strLen; i++) {
            if (!Character.isWhitespace(str.charAt(i))) {
                return false;
            }
        }
        return true;
    }

    public static boolean isNotBlank(String str) {
        return !isBlank(str);
    }
}

add utility StringUtil