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/**
 * Alipay.com Inc. Copyright (c) 2004-2020 All Rights Reserved.
 */
package com.aliyun.dc.opplat.sdk.api.utils;

/**
 * 较为复杂的字符串处理
 *
 * @author changlei.qcl
 * @version $Id: StringUtils.java, v 0.1 2020年07月27日 4:47 PM changlei.qcl Exp $
 */
public class StringUtils {

    private StringUtils() {}

    /**
     * 检查指定的字符串是否为空。
     * 
     * SysUtils.isEmpty(null) = true
     * SysUtils.isEmpty("") = true
     * SysUtils.isEmpty("   ") = true
     * SysUtils.isEmpty("abc") = false
     * 
     *
     * @param value 待检查的字符串
     * @return true/false
     */
    public static boolean isEmpty(String value) {
        int strLen;
        if (value == null || (strLen = value.length()) == 0) {
            return true;
        }
        for (int i = 0; i < strLen; i++) {
            if ((Character.isWhitespace(value.charAt(i)) == false)) {
                return false;
            }
        }
        return true;
    }

    /**
     * 检查对象是否为数字型字符串,包含负数开头的。
     */
    public static boolean isNumeric(Object obj) {
        if (obj == null) {
            return false;
        }
        char[] chars = obj.toString().toCharArray();
        int length = chars.length;
        if (length < 1) { return false; }

        int i = 0;
        if (length > 1 && chars[0] == '-') { i = 1; }

        for (; i < length; i++) {
            if (!Character.isDigit(chars[i])) {
                return false;
            }
        }
        return true;
    }

    /**
     * 检查指定的字符串列表是否不为空。
     */
    public static boolean areNotEmpty(String... values) {
        boolean result = true;
        if (values == null || values.length == 0) {
            result = false;
        } else {
            for (String value : values) {
                result &= !isEmpty(value);
            }
        }
        return result;
    }

    /**
     * 把通用字符编码的字符串转化为汉字编码。
     */
    public static String unicodeToChinese(String unicode) {
        StringBuilder out = new StringBuilder();
        if (!isEmpty(unicode)) {
            for (int i = 0; i < unicode.length(); i++) {
                out.append(unicode.charAt(i));
            }
        }
        return out.toString();
    }

    /**
     * 过滤不可见字符
     */
    public static String stripNonValidXMLCharacters(String input) {
        if (input == null || ("".equals(input))) { return ""; }
        StringBuilder out = new StringBuilder();
        char current;
        for (int i = 0; i < input.length(); i++) {
            current = input.charAt(i);
            if ((current == 0x9) || (current == 0xA) || (current == 0xD)
                    || ((current >= 0x20) && (current <= 0xD7FF))
                    || ((current >= 0xE000) && (current <= 0xFFFD))
                    || ((current >= 0x10000) && (current <= 0x10FFFF))) { out.append(current); }
        }
        return out.toString();
    }

    public static String leftPad(String str, int size, char padChar) {
        if (str == null) {
            return null;
        } else {
            int pads = size - str.length();
            if (pads <= 0) {
                return str;
            } else {
                return pads > 8192 ? leftPad(str, size, String.valueOf(padChar)) : padding(pads, padChar).concat(str);
            }
        }
    }

    public static String leftPad(String str, int size, String padStr) {
        if (str == null) {
            return null;
        } else {
            if (isEmpty(padStr)) {
                padStr = " ";
            }

            int padLen = padStr.length();
            int strLen = str.length();
            int pads = size - strLen;
            if (pads <= 0) {
                return str;
            } else if (padLen == 1 && pads <= 8192) {
                return leftPad(str, size, padStr.charAt(0));
            } else if (pads == padLen) {
                return padStr.concat(str);
            } else if (pads < padLen) {
                return padStr.substring(0, pads).concat(str);
            } else {
                char[] padding = new char[pads];
                char[] padChars = padStr.toCharArray();

                for (int i = 0; i < pads; ++i) {
                    padding[i] = padChars[i % padLen];
                }

                return (new String(padding)).concat(str);
            }
        }
    }

    private static String padding(int repeat, char padChar) throws IndexOutOfBoundsException {
        if (repeat < 0) {
            throw new IndexOutOfBoundsException("Cannot pad a negative amount: " + repeat);
        } else {
            char[] buf = new char[repeat];

            for (int i = 0; i < buf.length; ++i) {
                buf[i] = padChar;
            }

            return new String(buf);
        }
    }
}