/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */
package com.networknt.utility;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Majority of the methods are extracted from apache commons-lang to avoid include a
 * big jar file into the final package.
 *
 */
public class StringUtils {

    private static final String[] EMPTY_STRING_ARRAY = {};

    private static final int STRING_BUILDER_SIZE = 256;

    /**
     * Represents a failed index search.
     * @since 2.1
     */
    public static final int INDEX_NOT_FOUND = -1;

    /**
     * The empty String {@code ""}.
     * @since 2.0
     */
    public static final String EMPTY = "";

    /**
     * A String for a space character.
     *
     * @since 3.2
     */
    public static final String SPACE = " ";

    public static final String EMAIL_PATTERN = "^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@"
            + "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$";
    public static Pattern pattern = Pattern.compile(EMAIL_PATTERN);

    /**
     * Check if the string is null or empty
     *
     * @param value the value that is checked
     * @return true if the given value is either null or the empty string
     *
     */
    public static boolean isNullOrEmpty(String value) {
        return value == null || value.isEmpty();
    }

    public static String expandEnvVars(String text) {
        Map<String, String> envMap = System.getenv();
        String pattern = "\\$\\{([A-Za-z0-9-_]+)\\}";
        Pattern expr = Pattern.compile(pattern);
        Matcher matcher = expr.matcher(text);
        while (matcher.find()) {
            String envValue = envMap.get(matcher.group(1).toUpperCase());
            if (envValue == null) {
                envValue = "";
            } else {
                envValue = envValue.replace("\\", "\\\\");
            }
            Pattern subexpr = Pattern.compile(Pattern.quote(matcher.group(0)));
            text = subexpr.matcher(text).replaceAll(envValue);
        }
        return text;
    }

    /**
     * <p>Replaces a String with another String inside a larger String,
     * for the first {@code max} values of the search String.</p>
     *
     * <p>A {@code null} reference passed to this method is a no-op.</p>
     *
     * <pre>
     * StringUtils.replace(null, *, *, *)         = null
     * StringUtils.replace("", *, *, *)           = ""
     * StringUtils.replace("any", null, *, *)     = "any"
     * StringUtils.replace("any", *, null, *)     = "any"
     * StringUtils.replace("any", "", *, *)       = "any"
     * StringUtils.replace("any", *, *, 0)        = "any"
     * StringUtils.replace("abaa", "a", null, -1) = "abaa"
     * StringUtils.replace("abaa", "a", "", -1)   = "b"
     * StringUtils.replace("abaa", "a", "z", 0)   = "abaa"
     * StringUtils.replace("abaa", "a", "z", 1)   = "zbaa"
     * StringUtils.replace("abaa", "a", "z", 2)   = "zbza"
     * StringUtils.replace("abaa", "a", "z", -1)  = "zbzz"
     * </pre>
     *
     * @param text  text to search and replace in, may be null
     * @param searchString  the String to search for, may be null
     * @param replacement  the String to replace it with, may be null
     * @param max  maximum number of values to replace, or {@code -1} if no maximum
     * @return the text with any replacements processed,
     *  {@code null} if null String input
     */
    public static String replace(final String text, final String searchString, final String replacement, final int max) {
        return replace(text, searchString, replacement, max, false);
    }

    /**
     * <p>Replaces a String with another String inside a larger String,
     * for the first {@code max} values of the search String,
     * case sensitively/insensisitively based on {@code ignoreCase} value.</p>
     *
     * <p>A {@code null} reference passed to this method is a no-op.</p>
     *
     * <pre>
     * StringUtils.replace(null, *, *, *, false)         = null
     * StringUtils.replace("", *, *, *, false)           = ""
     * StringUtils.replace("any", null, *, *, false)     = "any"
     * StringUtils.replace("any", *, null, *, false)     = "any"
     * StringUtils.replace("any", "", *, *, false)       = "any"
     * StringUtils.replace("any", *, *, 0, false)        = "any"
     * StringUtils.replace("abaa", "a", null, -1, false) = "abaa"
     * StringUtils.replace("abaa", "a", "", -1, false)   = "b"
     * StringUtils.replace("abaa", "a", "z", 0, false)   = "abaa"
     * StringUtils.replace("abaa", "A", "z", 1, false)   = "abaa"
     * StringUtils.replace("abaa", "A", "z", 1, true)   = "zbaa"
     * StringUtils.replace("abAa", "a", "z", 2, true)   = "zbza"
     * StringUtils.replace("abAa", "a", "z", -1, true)  = "zbzz"
     * </pre>
     *
     * @param text  text to search and replace in, may be null
     * @param searchString  the String to search for (case insensitive), may be null
     * @param replacement  the String to replace it with, may be null
     * @param max  maximum number of values to replace, or {@code -1} if no maximum
     * @param ignoreCase if true replace is case insensitive, otherwise case sensitive
     * @return the text with any replacements processed,
     *  {@code null} if null String input
     */
    private static String replace(final String text, String searchString, final String replacement, int max, final boolean ignoreCase) {
        if (isEmpty(text) || isEmpty(searchString) || replacement == null || max == 0) {
            return text;
        }
        String searchText = text;
        if (ignoreCase) {
            searchText = text.toLowerCase();
            searchString = searchString.toLowerCase();
        }
        int start = 0;
        int end = searchText.indexOf(searchString, start);
        if (end == INDEX_NOT_FOUND) {
            return text;
        }
        final int replLength = searchString.length();
        int increase = replacement.length() - replLength;
        increase = increase < 0 ? 0 : increase;
        increase *= max < 0 ? 16 : max > 64 ? 64 : max;
        final StringBuilder buf = new StringBuilder(text.length() + increase);
        while (end != INDEX_NOT_FOUND) {
            buf.append(text, start, end).append(replacement);
            start = end + replLength;
            if (--max == 0) {
                break;
            }
            end = searchText.indexOf(searchString, start);
        }
        buf.append(text, start, text.length());
        return buf.toString();
    }

    // Replacing
    /**
     * <p>Replaces a String with another String inside a larger String, once.</p>
     *
     * <p>A {@code null} reference passed to this method is a no-op.</p>
     *
     * <pre>
     * StringUtils.replaceOnce(null, *, *)        = null
     * StringUtils.replaceOnce("", *, *)          = ""
     * StringUtils.replaceOnce("any", null, *)    = "any"
     * StringUtils.replaceOnce("any", *, null)    = "any"
     * StringUtils.replaceOnce("any", "", *)      = "any"
     * StringUtils.replaceOnce("aba", "a", null)  = "aba"
     * StringUtils.replaceOnce("aba", "a", "")    = "ba"
     * StringUtils.replaceOnce("aba", "a", "z")   = "zba"
     * </pre>
     *
     * @see #replace(String text, String searchString, String replacement, int max)
     * @param text  text to search and replace in, may be null
     * @param searchString  the String to search for, may be null
     * @param replacement  the String to replace with, may be null
     * @return the text with any replacements processed,
     *  {@code null} if null String input
     */
    public static String replaceOnce(final String text, final String searchString, final String replacement) {
        return replace(text, searchString, replacement, 1);
    }

    // Empty checks
    //-----------------------------------------------------------------------
    /**
     * <p>Checks if a CharSequence is empty ("") or null.</p>
     *
     * <pre>
     * StringUtils.isEmpty(null)      = true
     * StringUtils.isEmpty("")        = true
     * StringUtils.isEmpty(" ")       = false
     * StringUtils.isEmpty("bob")     = false
     * StringUtils.isEmpty("  bob  ") = false
     * </pre>
     *
     * <p>NOTE: This method changed in Lang version 2.0.
     * It no longer trims the CharSequence.
     * That functionality is available in isBlank().</p>
     *
     * @param cs  the CharSequence to check, may be null
     * @return {@code true} if the CharSequence is empty or null
     * @since 3.0 Changed signature from isEmpty(String) to isEmpty(CharSequence)
     */
    public static boolean isEmpty(final CharSequence cs) {
        return cs == null || cs.length() == 0;
    }

    /**
     * <p>Right pad a String with a specified character.</p>
     *
     * <p>The String is padded to the size of {@code size}.</p>
     *
     * <pre>
     * StringUtils.rightPad(null, *, *)     = null
     * StringUtils.rightPad("", 3, 'z')     = "zzz"
     * StringUtils.rightPad("bat", 3, 'z')  = "bat"
     * StringUtils.rightPad("bat", 5, 'z')  = "batzz"
     * StringUtils.rightPad("bat", 1, 'z')  = "bat"
     * StringUtils.rightPad("bat", -1, 'z') = "bat"
     * </pre>
     *
     * @param str  the String to pad out, may be null
     * @param size  the size to pad to
     * @param padChar  the character to pad with
     * @return right padded String or original String if no padding is necessary,
     *  {@code null} if null String input
     * @since 2.0
     */
    public static String rightPad(final String str, final int size, final char padChar) {
        if (str == null) {
            return null;
        }
        final int pads = size - str.length();
        if (pads <= 0) {
            return str; // returns original String when possible
        }
        if (pads > PAD_LIMIT) {
            return rightPad(str, size, String.valueOf(padChar));
        }
        return str.concat(repeat(padChar, pads));
    }

    /**
     * <p>The maximum size to which the padding constant(s) can expand.</p>
     */
    private static final int PAD_LIMIT = 8192;

    /**
     * <p>Returns padding using the specified delimiter repeated
     * to a given length.</p>
     *
     * <pre>
     * StringUtils.repeat('e', 0)  = ""
     * StringUtils.repeat('e', 3)  = "eee"
     * StringUtils.repeat('e', -2) = ""
     * </pre>
     *
     * <p>Note: this method does not support padding with
     * <a href="http://www.unicode.org/glossary/#supplementary_character">Unicode Supplementary Characters</a>
     * as they require a pair of {@code char}s to be represented.
     * If you are needing to support full I18N of your applications
     * consider using repeat(String, int) instead.
     * </p>
     *
     * @param ch  character to repeat
     * @param repeat  number of times to repeat char, negative treated as zero
     * @return String with repeated character
     */
    public static String repeat(final char ch, final int repeat) {
        if (repeat <= 0) {
            return EMPTY;
        }
        final char[] buf = new char[repeat];
        for (int i = repeat - 1; i >= 0; i--) {
            buf[i] = ch;
        }
        return new String(buf);
    }

    /**
     * <p>Right pad a String with a specified String.</p>
     *
     * <p>The String is padded to the size of {@code size}.</p>
     *
     * <pre>
     * StringUtils.rightPad(null, *, *)      = null
     * StringUtils.rightPad("", 3, "z")      = "zzz"
     * StringUtils.rightPad("bat", 3, "yz")  = "bat"
     * StringUtils.rightPad("bat", 5, "yz")  = "batyz"
     * StringUtils.rightPad("bat", 8, "yz")  = "batyzyzy"
     * StringUtils.rightPad("bat", 1, "yz")  = "bat"
     * StringUtils.rightPad("bat", -1, "yz") = "bat"
     * StringUtils.rightPad("bat", 5, null)  = "bat  "
     * StringUtils.rightPad("bat", 5, "")    = "bat  "
     * </pre>
     *
     * @param str  the String to pad out, may be null
     * @param size  the size to pad to
     * @param padStr  the String to pad with, null or empty treated as single space
     * @return right padded String or original String if no padding is necessary,
     *  {@code null} if null String input
     */
    public static String rightPad(final String str, final int size, String padStr) {
        if (str == null) {
            return null;
        }
        if (isEmpty(padStr)) {
            padStr = SPACE;
        }
        final int padLen = padStr.length();
        final int strLen = str.length();
        final int pads = size - strLen;
        if (pads <= 0) {
            return str; // returns original String when possible
        }
        if (padLen == 1 && pads <= PAD_LIMIT) {
            return rightPad(str, size, padStr.charAt(0));
        }

        if (pads == padLen) {
            return str.concat(padStr);
        } else if (pads < padLen) {
            return str.concat(padStr.substring(0, pads));
        } else {
            final char[] padding = new char[pads];
            final char[] padChars = padStr.toCharArray();
            for (int i = 0; i < pads; i++) {
                padding[i] = padChars[i % padLen];
            }
            return str.concat(new String(padding));
        }
    }

    /**
     * <p>Checks if a CharSequence is empty (""), null or whitespace only.</p>
     *
     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
     *
     * <pre>
     * StringUtils.isBlank(null)      = true
     * StringUtils.isBlank("")        = true
     * StringUtils.isBlank(" ")       = true
     * StringUtils.isBlank("bob")     = false
     * StringUtils.isBlank("  bob  ") = false
     * </pre>
     *
     * @param cs  the CharSequence to check, may be null
     * @return {@code true} if the CharSequence is null, empty or whitespace only
     * @since 2.0
     * @since 3.0 Changed signature from isBlank(String) to isBlank(CharSequence)
     */
    public static boolean isBlank(final CharSequence cs) {
        int strLen;
        if (cs == null || (strLen = cs.length()) == 0) {
            return true;
        }
        for (int i = 0; i < strLen; i++) {
            if (!Character.isWhitespace(cs.charAt(i))) {
                return false;
            }
        }
        return true;
    }

    /**
     * <p>Checks if a CharSequence is not empty (""), not null and not whitespace only.</p>
     *
     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
     *
     * <pre>
     * StringUtils.isNotBlank(null)      = false
     * StringUtils.isNotBlank("")        = false
     * StringUtils.isNotBlank(" ")       = false
     * StringUtils.isNotBlank("bob")     = true
     * StringUtils.isNotBlank("  bob  ") = true
     * </pre>
     *
     * @param cs  the CharSequence to check, may be null
     * @return {@code true} if the CharSequence is
     *  not empty and not null and not whitespace only
     * @since 2.0
     * @since 3.0 Changed signature from isNotBlank(String) to isNotBlank(CharSequence)
     */
    public static boolean isNotBlank(final CharSequence cs) {
        return !isBlank(cs);
    }

    // SubStringAfter/SubStringBefore
    //-----------------------------------------------------------------------
    /**
     * <p>Gets the substring before the first occurrence of a separator.
     * The separator is not returned.</p>
     *
     * <p>A {@code null} string input will return {@code null}.
     * An empty ("") string input will return the empty string.
     * A {@code null} separator will return the input string.</p>
     *
     * <p>If nothing is found, the string input is returned.</p>
     *
     * <pre>
     * StringUtils.substringBefore(null, *)      = null
     * StringUtils.substringBefore("", *)        = ""
     * StringUtils.substringBefore("abc", "a")   = ""
     * StringUtils.substringBefore("abcba", "b") = "a"
     * StringUtils.substringBefore("abc", "c")   = "ab"
     * StringUtils.substringBefore("abc", "d")   = "abc"
     * StringUtils.substringBefore("abc", "")    = ""
     * StringUtils.substringBefore("abc", null)  = "abc"
     * </pre>
     *
     * @param str  the String to get a substring from, may be null
     * @param separator  the String to search for, may be null
     * @return the substring before the first occurrence of the separator,
     *  {@code null} if null String input
     * @since 2.0
     */
    public static String substringBefore(final String str, final String separator) {
        if (isEmpty(str) || separator == null) {
            return str;
        }
        if (separator.isEmpty()) {
            return EMPTY;
        }
        final int pos = str.indexOf(separator);
        if (pos == INDEX_NOT_FOUND) {
            return str;
        }
        return str.substring(0, pos);
    }

    /**
     * <p>Gets the substring after the first occurrence of a separator.
     * The separator is not returned.</p>
     *
     * <p>A {@code null} string input will return {@code null}.
     * An empty ("") string input will return the empty string.
     * A {@code null} separator will return the empty string if the
     * input string is not {@code null}.</p>
     *
     * <p>If nothing is found, the empty string is returned.</p>
     *
     * <pre>
     * StringUtils.substringAfter(null, *)      = null
     * StringUtils.substringAfter("", *)        = ""
     * StringUtils.substringAfter(*, null)      = ""
     * StringUtils.substringAfter("abc", "a")   = "bc"
     * StringUtils.substringAfter("abcba", "b") = "cba"
     * StringUtils.substringAfter("abc", "c")   = ""
     * StringUtils.substringAfter("abc", "d")   = ""
     * StringUtils.substringAfter("abc", "")    = "abc"
     * </pre>
     *
     * @param str  the String to get a substring from, may be null
     * @param separator  the String to search for, may be null
     * @return the substring after the first occurrence of the separator,
     *  {@code null} if null String input
     * @since 2.0
     */
    public static String substringAfter(final String str, final String separator) {
        if (isEmpty(str)) {
            return str;
        }
        if (separator == null) {
            return EMPTY;
        }
        final int pos = str.indexOf(separator);
        if (pos == INDEX_NOT_FOUND) {
            return EMPTY;
        }
        return str.substring(pos + separator.length());
    }

    /**
     * <p>Gets the substring after the last occurrence of a separator.
     * The separator is not returned.</p>
     *
     * <p>A {@code null} string input will return {@code null}.
     * An empty ("") string input will return the empty string.
     * An empty or {@code null} separator will return the empty string if
     * the input string is not {@code null}.</p>
     *
     * <p>If nothing is found, the empty string is returned.</p>
     *
     * <pre>
     * StringUtils.substringAfterLast(null, *)      = null
     * StringUtils.substringAfterLast("", *)        = ""
     * StringUtils.substringAfterLast(*, "")        = ""
     * StringUtils.substringAfterLast(*, null)      = ""
     * StringUtils.substringAfterLast("abc", "a")   = "bc"
     * StringUtils.substringAfterLast("abcba", "b") = "a"
     * StringUtils.substringAfterLast("abc", "c")   = ""
     * StringUtils.substringAfterLast("a", "a")     = ""
     * StringUtils.substringAfterLast("a", "z")     = ""
     * </pre>
     *
     * @param str  the String to get a substring from, may be null
     * @param separator  the String to search for, may be null
     * @return the substring after the last occurrence of the separator,
     *  {@code null} if null String input
     * @since 2.0
     */
    public static String substringAfterLast(final String str, final String separator) {
        if (isEmpty(str)) {
            return str;
        }
        if (isEmpty(separator)) {
            return EMPTY;
        }
        final int pos = str.lastIndexOf(separator);
        if (pos == INDEX_NOT_FOUND || pos == str.length() - separator.length()) {
            return EMPTY;
        }
        return str.substring(pos + separator.length());
    }

    /**
     * <p>Gets the substring before the last occurrence of a separator.
     * The separator is not returned.</p>
     *
     * <p>A {@code null} string input will return {@code null}.
     * An empty ("") string input will return the empty string.
     * An empty or {@code null} separator will return the input string.</p>
     *
     * <p>If nothing is found, the string input is returned.</p>
     *
     * <pre>
     * StringUtils.substringBeforeLast(null, *)      = null
     * StringUtils.substringBeforeLast("", *)        = ""
     * StringUtils.substringBeforeLast("abcba", "b") = "abc"
     * StringUtils.substringBeforeLast("abc", "c")   = "ab"
     * StringUtils.substringBeforeLast("a", "a")     = ""
     * StringUtils.substringBeforeLast("a", "z")     = "a"
     * StringUtils.substringBeforeLast("a", null)    = "a"
     * StringUtils.substringBeforeLast("a", "")      = "a"
     * </pre>
     *
     * @param str  the String to get a substring from, may be null
     * @param separator  the String to search for, may be null
     * @return the substring before the last occurrence of the separator,
     *  {@code null} if null String input
     * @since 2.0
     */
    public static String substringBeforeLast(final String str, final String separator) {
        if (isEmpty(str) || isEmpty(separator)) {
            return str;
        }
        final int pos = str.lastIndexOf(separator);
        if (pos == INDEX_NOT_FOUND) {
            return str;
        }
        return str.substring(0, pos);
    }

    // Count matches
    //-----------------------------------------------------------------------
    /**
     * <p>Counts how many times the substring appears in the larger string.</p>
     *
     * <p>A {@code null} or empty ("") String input returns {@code 0}.</p>
     *
     * <pre>
     * StringUtils.countMatches(null, *)       = 0
     * StringUtils.countMatches("", *)         = 0
     * StringUtils.countMatches("abba", null)  = 0
     * StringUtils.countMatches("abba", "")    = 0
     * StringUtils.countMatches("abba", "a")   = 2
     * StringUtils.countMatches("abba", "ab")  = 1
     * StringUtils.countMatches("abba", "xxx") = 0
     * </pre>
     *
     * @param str  the CharSequence to check, may be null
     * @param sub  the substring to count, may be null
     * @return the number of occurrences, 0 if either CharSequence is {@code null}
     * @since 3.0 Changed signature from countMatches(String, String) to countMatches(CharSequence, CharSequence)
     */
    public static int countMatches(final CharSequence str, final CharSequence sub) {
        if (isEmpty(str) || isEmpty(sub)) {
            return 0;
        }
        int count = 0;
        int idx = 0;
        while ((idx = CharSequenceUtils.indexOf(str, sub, idx)) != INDEX_NOT_FOUND) {
            count++;
            idx += sub.length();
        }
        return count;
    }

    /**
     * <p>Counts how many times the char appears in the given string.</p>
     *
     * <p>A {@code null} or empty ("") String input returns {@code 0}.</p>
     *
     * <pre>
     * StringUtils.countMatches(null, *)       = 0
     * StringUtils.countMatches("", *)         = 0
     * StringUtils.countMatches("abba", 0)  = 0
     * StringUtils.countMatches("abba", 'a')   = 2
     * StringUtils.countMatches("abba", 'b')  = 2
     * StringUtils.countMatches("abba", 'x') = 0
     * </pre>
     *
     * @param str  the CharSequence to check, may be null
     * @param ch  the char to count
     * @return the number of occurrences, 0 if the CharSequence is {@code null}
     * @since 3.4
     */
    public static int countMatches(final CharSequence str, final char ch) {
        if (isEmpty(str)) {
            return 0;
        }
        int count = 0;
        // We could also call str.toCharArray() for faster look ups but that would generate more garbage.
        for (int i = 0; i < str.length(); i++) {
            if (ch == str.charAt(i)) {
                count++;
            }
        }
        return count;
    }

    /**
     * <p>Removes control characters (char &lt;= 32) from both
     * ends of this String returning an empty String ("") if the String
     * is empty ("") after the trim or if it is {@code null}.
     *
     * <p>The String is trimmed using {@link String#trim()}.
     * Trim removes start and end characters &lt;= 32.</p>
     *
     * <pre>
     * StringUtils.trimToEmpty(null)          = ""
     * StringUtils.trimToEmpty("")            = ""
     * StringUtils.trimToEmpty("     ")       = ""
     * StringUtils.trimToEmpty("abc")         = "abc"
     * StringUtils.trimToEmpty("    abc    ") = "abc"
     * </pre>
     *
     * @param str  the String to be trimmed, may be null
     * @return the trimmed String, or an empty String if {@code null} input
     * @since 2.0
     */
    public static String trimToEmpty(final String str) {
        return str == null ? EMPTY : str.trim();
    }

    /**
     * <p>Removes a substring only if it is at the end of a source string,
     * otherwise returns the source string.</p>
     *
     * <p>A {@code null} source string will return {@code null}.
     * An empty ("") source string will return the empty string.
     * A {@code null} search string will return the source string.</p>
     *
     * <pre>
     * StringUtils.removeEnd(null, *)      = null
     * StringUtils.removeEnd("", *)        = ""
     * StringUtils.removeEnd(*, null)      = *
     * StringUtils.removeEnd("www.domain.com", ".com.")  = "www.domain.com"
     * StringUtils.removeEnd("www.domain.com", ".com")   = "www.domain"
     * StringUtils.removeEnd("www.domain.com", "domain") = "www.domain.com"
     * StringUtils.removeEnd("abc", "")    = "abc"
     * </pre>
     *
     * @param str  the source String to search, may be null
     * @param remove  the String to search for and remove, may be null
     * @return the substring with the string removed if found,
     *  {@code null} if null String input
     * @since 2.1
     */
    public static String removeEnd(final String str, final String remove) {
        if (isEmpty(str) || isEmpty(remove)) {
            return str;
        }
        if (str.endsWith(remove)) {
            return str.substring(0, str.length() - remove.length());
        }
        return str;
    }

    /**
     * <p>Strips any of a set of characters from the end of a String.</p>
     *
     * <p>A {@code null} input String returns {@code null}.
     * An empty string ("") input returns the empty string.</p>
     *
     * <p>If the stripChars String is {@code null}, whitespace is
     * stripped as defined by {@link Character#isWhitespace(char)}.</p>
     *
     * <pre>
     * StringUtils.stripEnd(null, *)          = null
     * StringUtils.stripEnd("", *)            = ""
     * StringUtils.stripEnd("abc", "")        = "abc"
     * StringUtils.stripEnd("abc", null)      = "abc"
     * StringUtils.stripEnd("  abc", null)    = "  abc"
     * StringUtils.stripEnd("abc  ", null)    = "abc"
     * StringUtils.stripEnd(" abc ", null)    = " abc"
     * StringUtils.stripEnd("  abcyx", "xyz") = "  abc"
     * StringUtils.stripEnd("120.00", ".0")   = "12"
     * </pre>
     *
     * @param str  the String to remove characters from, may be null
     * @param stripChars  the set of characters to remove, null treated as whitespace
     * @return the stripped String, {@code null} if null String input
     */
    public static String stripEnd(final String str, final String stripChars) {
        int end;
        if (str == null || (end = str.length()) == 0) {
            return str;
        }

        if (stripChars == null) {
            while (end != 0 && Character.isWhitespace(str.charAt(end - 1))) {
                end--;
            }
        } else if (stripChars.isEmpty()) {
            return str;
        } else {
            while (end != 0 && stripChars.indexOf(str.charAt(end - 1)) != INDEX_NOT_FOUND) {
                end--;
            }
        }
        return str.substring(0, end);
    }

    /**
     * <p>Case insensitive removal of a substring if it is at the beginning of a source string,
     * otherwise returns the source string.</p>
     *
     * <p>A {@code null} source string will return {@code null}.
     * An empty ("") source string will return the empty string.
     * A {@code null} search string will return the source string.</p>
     *
     * <pre>
     * StringUtils.removeStartIgnoreCase(null, *)      = null
     * StringUtils.removeStartIgnoreCase("", *)        = ""
     * StringUtils.removeStartIgnoreCase(*, null)      = *
     * StringUtils.removeStartIgnoreCase("www.domain.com", "www.")   = "domain.com"
     * StringUtils.removeStartIgnoreCase("www.domain.com", "WWW.")   = "domain.com"
     * StringUtils.removeStartIgnoreCase("domain.com", "www.")       = "domain.com"
     * StringUtils.removeStartIgnoreCase("www.domain.com", "domain") = "www.domain.com"
     * StringUtils.removeStartIgnoreCase("abc", "")    = "abc"
     * </pre>
     *
     * @param str  the source String to search, may be null
     * @param remove  the String to search for (case insensitive) and remove, may be null
     * @return the substring with the string removed if found,
     *  {@code null} if null String input
     * @since 2.4
     */
    public static String removeStartIgnoreCase(final String str, final String remove) {
        if (isEmpty(str) || isEmpty(remove)) {
            return str;
        }
        if (startsWithIgnoreCase(str, remove)) {
            return str.substring(remove.length());
        }
        return str;
    }

    /**
     * <p>Case insensitive check if a CharSequence starts with a specified prefix.</p>
     *
     * <p>{@code null}s are handled without exceptions. Two {@code null}
     * references are considered to be equal. The comparison is case insensitive.</p>
     *
     * <pre>
     * StringUtils.startsWithIgnoreCase(null, null)      = true
     * StringUtils.startsWithIgnoreCase(null, "abc")     = false
     * StringUtils.startsWithIgnoreCase("abcdef", null)  = false
     * StringUtils.startsWithIgnoreCase("abcdef", "abc") = true
     * StringUtils.startsWithIgnoreCase("ABCDEF", "abc") = true
     * </pre>
     *
     * @see java.lang.String#startsWith(String)
     * @param str  the CharSequence to check, may be null
     * @param prefix the prefix to find, may be null
     * @return {@code true} if the CharSequence starts with the prefix, case insensitive, or
     *  both {@code null}
     * @since 2.4
     * @since 3.0 Changed signature from startsWithIgnoreCase(String, String) to startsWithIgnoreCase(CharSequence, CharSequence)
     */
    public static boolean startsWithIgnoreCase(final CharSequence str, final CharSequence prefix) {
        return startsWith(str, prefix, true);
    }

    /**
     * <p>Check if a CharSequence starts with a specified prefix (optionally case insensitive).</p>
     *
     * @see java.lang.String#startsWith(String)
     * @param str  the CharSequence to check, may be null
     * @param prefix the prefix to find, may be null
     * @param ignoreCase indicates whether the compare should ignore case
     *  (case insensitive) or not.
     * @return {@code true} if the CharSequence starts with the prefix or
     *  both {@code null}
     */
    private static boolean startsWith(final CharSequence str, final CharSequence prefix, final boolean ignoreCase) {
        if (str == null || prefix == null) {
            return str == prefix;
        }
        if (prefix.length() > str.length()) {
            return false;
        }
        return CharSequenceUtils.regionMatches(str, ignoreCase, 0, prefix, 0, prefix.length());
    }

    /**
     * <p>Checks if CharSequence contains a search CharSequence irrespective of case,
     * handling {@code null}. Case-insensitivity is defined as by
     * {@link String#equalsIgnoreCase(String)}.
     *
     * <p>A {@code null} CharSequence will return {@code false}.</p>
     *
     * <pre>
     * StringUtils.containsIgnoreCase(null, *) = false
     * StringUtils.containsIgnoreCase(*, null) = false
     * StringUtils.containsIgnoreCase("", "") = true
     * StringUtils.containsIgnoreCase("abc", "") = true
     * StringUtils.containsIgnoreCase("abc", "a") = true
     * StringUtils.containsIgnoreCase("abc", "z") = false
     * StringUtils.containsIgnoreCase("abc", "A") = true
     * StringUtils.containsIgnoreCase("abc", "Z") = false
     * </pre>
     *
     * @param str  the CharSequence to check, may be null
     * @param searchStr  the CharSequence to find, may be null
     * @return true if the CharSequence contains the search CharSequence irrespective of
     * case or false if not or {@code null} string input
     * @since 3.0 Changed signature from containsIgnoreCase(String, String) to containsIgnoreCase(CharSequence, CharSequence)
     */
    public static boolean containsIgnoreCase(final CharSequence str, final CharSequence searchStr) {
        if (str == null || searchStr == null) {
            return false;
        }
        final int len = searchStr.length();
        final int max = str.length() - len;
        for (int i = 0; i <= max; i++) {
            if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, len)) {
                return true;
            }
        }
        return false;
    }

    /**
     * <p>Removes a substring only if it is at the beginning of a source string,
     * otherwise returns the source string.</p>
     *
     * <p>A {@code null} source string will return {@code null}.
     * An empty ("") source string will return the empty string.
     * A {@code null} search string will return the source string.</p>
     *
     * <pre>
     * StringUtils.removeStart(null, *)      = null
     * StringUtils.removeStart("", *)        = ""
     * StringUtils.removeStart(*, null)      = *
     * StringUtils.removeStart("www.domain.com", "www.")   = "domain.com"
     * StringUtils.removeStart("domain.com", "www.")       = "domain.com"
     * StringUtils.removeStart("www.domain.com", "domain") = "www.domain.com"
     * StringUtils.removeStart("abc", "")    = "abc"
     * </pre>
     *
     * @param str  the source String to search, may be null
     * @param remove  the String to search for and remove, may be null
     * @return the substring with the string removed if found,
     *  {@code null} if null String input
     * @since 2.1
     */
    public static String removeStart(final String str, final String remove) {
        if (isEmpty(str) || isEmpty(remove)) {
            return str;
        }
        if (str.startsWith(remove)){
            return str.substring(remove.length());
        }
        return str;
    }

    /**
     * Performs the logic for the {@code split} and
     * {@code splitPreserveAllTokens} methods that return a maximum array
     * length.
     *
     * @param str  the String to parse, may be {@code null}
     * @param separatorChars the separate character
     * @param max  the maximum number of elements to include in the
     *  array. A zero or negative value implies no limit.
     * @param preserveAllTokens if {@code true}, adjacent separators are
     * treated as empty token separators; if {@code false}, adjacent
     * separators are treated as one separator.
     * @return an array of parsed Strings, {@code null} if null String input
     */
    private static String[] splitWorker(final String str, final String separatorChars, final int max, final boolean preserveAllTokens) {
        // Performance tuned for 2.0 (JDK1.4)
        // Direct code is quicker than StringTokenizer.
        // Also, StringTokenizer uses isSpace() not isWhitespace()

        if (str == null) {
            return null;
        }
        final int len = str.length();
        if (len == 0) {
            return new String[0];
        }
        final List<String> list = new ArrayList<>();
        int sizePlus1 = 1;
        int i = 0, start = 0;
        boolean match = false;
        boolean lastMatch = false;
        if (separatorChars == null) {
            // Null separator means use whitespace
            while (i < len) {
                if (Character.isWhitespace(str.charAt(i))) {
                    if (match || preserveAllTokens) {
                        lastMatch = true;
                        if (sizePlus1++ == max) {
                            i = len;
                            lastMatch = false;
                        }
                        list.add(str.substring(start, i));
                        match = false;
                    }
                    start = ++i;
                    continue;
                }
                lastMatch = false;
                match = true;
                i++;
            }
        } else if (separatorChars.length() == 1) {
            // Optimise 1 character case
            final char sep = separatorChars.charAt(0);
            while (i < len) {
                if (str.charAt(i) == sep) {
                    if (match || preserveAllTokens) {
                        lastMatch = true;
                        if (sizePlus1++ == max) {
                            i = len;
                            lastMatch = false;
                        }
                        list.add(str.substring(start, i));
                        match = false;
                    }
                    start = ++i;
                    continue;
                }
                lastMatch = false;
                match = true;
                i++;
            }
        } else {
            // standard case
            while (i < len) {
                if (separatorChars.indexOf(str.charAt(i)) >= 0) {
                    if (match || preserveAllTokens) {
                        lastMatch = true;
                        if (sizePlus1++ == max) {
                            i = len;
                            lastMatch = false;
                        }
                        list.add(str.substring(start, i));
                        match = false;
                    }
                    start = ++i;
                    continue;
                }
                lastMatch = false;
                match = true;
                i++;
            }
        }
        if (match || (preserveAllTokens && lastMatch)) {
            list.add(str.substring(start, i));
        }
        return list.toArray(new String[list.size()]);
    }

    /**
     * Performs the logic for the {@code split} and
     * {@code splitPreserveAllTokens} methods that do not return a
     * maximum array length.
     *
     * @param str  the String to parse, may be {@code null}
     * @param separatorChar the separate character
     * @param preserveAllTokens if {@code true}, adjacent separators are
     * treated as empty token separators; if {@code false}, adjacent
     * separators are treated as one separator.
     * @return an array of parsed Strings, {@code null} if null String input
     */
    private static String[] splitWorker(final String str, final char separatorChar, final boolean preserveAllTokens) {
        // Performance tuned for 2.0 (JDK1.4)

        if (str == null) {
            return null;
        }
        final int len = str.length();
        if (len == 0) {
            return new String[0];
        }
        final List<String> list = new ArrayList<>();
        int i = 0, start = 0;
        boolean match = false;
        boolean lastMatch = false;
        while (i < len) {
            if (str.charAt(i) == separatorChar) {
                if (match || preserveAllTokens) {
                    list.add(str.substring(start, i));
                    match = false;
                    lastMatch = true;
                }
                start = ++i;
                continue;
            }
            lastMatch = false;
            match = true;
            i++;
        }
        if (match || (preserveAllTokens && lastMatch)) {
            list.add(str.substring(start, i));
        }
        return list.toArray(new String[list.size()]);
    }

    /**
     * <p>Splits the provided text into an array, separators specified.
     * This is an alternative to using StringTokenizer.</p>
     *
     * <p>The separator is not included in the returned String array.
     * Adjacent separators are treated as one separator.
     * For more control over the split use the StrTokenizer class.</p>
     *
     * <p>A {@code null} input String returns {@code null}.
     * A {@code null} separatorChars splits on whitespace.</p>
     *
     * <pre>
     * StringUtils.split(null, *)         = null
     * StringUtils.split("", *)           = []
     * StringUtils.split("abc def", null) = ["abc", "def"]
     * StringUtils.split("abc def", " ")  = ["abc", "def"]
     * StringUtils.split("abc  def", " ") = ["abc", "def"]
     * StringUtils.split("ab:cd:ef", ":") = ["ab", "cd", "ef"]
     * </pre>
     *
     * @param str  the String to parse, may be null
     * @param separatorChars  the characters used as the delimiters,
     *  {@code null} splits on whitespace
     * @return an array of parsed Strings, {@code null} if null String input
     */
    public static String[] split(final String str, final String separatorChars) {
        return splitWorker(str, separatorChars, -1, false);
    }

    /**
     * <p>Splits the provided text into an array, separator specified.
     * This is an alternative to using StringTokenizer.</p>
     *
     * <p>The separator is not included in the returned String array.
     * Adjacent separators are treated as one separator.
     * For more control over the split use the StrTokenizer class.</p>
     *
     * <p>A {@code null} input String returns {@code null}.</p>
     *
     * <pre>
     * StringUtils.split(null, *)         = null
     * StringUtils.split("", *)           = []
     * StringUtils.split("a.b.c", '.')    = ["a", "b", "c"]
     * StringUtils.split("a..b.c", '.')   = ["a", "b", "c"]
     * StringUtils.split("a:b:c", '.')    = ["a:b:c"]
     * StringUtils.split("a b c", ' ')    = ["a", "b", "c"]
     * </pre>
     *
     * @param str  the String to parse, may be null
     * @param separatorChar  the character used as the delimiter
     * @return an array of parsed Strings, {@code null} if null String input
     * @since 2.0
     */
    public static String[] split(final String str, final char separatorChar) {
        return splitWorker(str, separatorChar, false);
    }

    /**
     * <p>Joins the elements of the provided array into a single String
     * containing the provided list of elements.</p>
     *
     * <p>No delimiter is added before or after the list.
     * Null objects or empty strings within the array are represented by
     * empty strings.</p>
     *
     * <pre>
     * StringUtils.join(null, *)               = null
     * StringUtils.join([], *)                 = ""
     * StringUtils.join([null], *)             = ""
     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
     * StringUtils.join(["a", "b", "c"], null) = "abc"
     * StringUtils.join([null, "", "a"], ';')  = ";;a"
     * </pre>
     *
     * @param array  the array of values to join together, may be null
     * @param separator  the separator character to use
     * @return the joined String, {@code null} if null array input
     * @since 2.0
     */
    public static String join(final Object[] array, final char separator) {
        if (array == null) {
            return null;
        }
        return join(array, separator, 0, array.length);
    }

    /**
     * <p>Joins the elements of the provided array into a single String
     * containing the provided list of elements.</p>
     *
     * <p>No delimiter is added before or after the list.
     * Null objects or empty strings within the array are represented by
     * empty strings.</p>
     *
     * <pre>
     * StringUtils.join(null, *)               = null
     * StringUtils.join([], *)                 = ""
     * StringUtils.join([null], *)             = ""
     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
     * StringUtils.join(["a", "b", "c"], null) = "abc"
     * StringUtils.join([null, "", "a"], ';')  = ";;a"
     * </pre>
     *
     * @param array  the array of values to join together, may be null
     * @param separator  the separator character to use
     * @param startIndex the first index to start joining from.  It is
     * an error to pass in an end index past the end of the array
     * @param endIndex the index to stop joining from (exclusive). It is
     * an error to pass in an end index past the end of the array
     * @return the joined String, {@code null} if null array input
     * @since 2.0
     */
    public static String join(final Object[] array, final char separator, final int startIndex, final int endIndex) {
        if (array == null) {
            return null;
        }
        final int noOfItems = endIndex - startIndex;
        if (noOfItems <= 0) {
            return EMPTY;
        }
        final StringBuilder buf = newStringBuilder(noOfItems);
        for (int i = startIndex; i < endIndex; i++) {
            if (i > startIndex) {
                buf.append(separator);
            }
            if (array[i] != null) {
                buf.append(array[i]);
            }
        }
        return buf.toString();
    }

    /**
     * <p>Joins the elements of the provided {@code Iterator} into
     * a single String containing the provided elements.</p>
     *
     * <p>No delimiter is added before or after the list. Null objects or empty
     * strings within the iteration are represented by empty strings.</p>
     *
     * <p>See the examples here: {@link #join(Object[],char)}. </p>
     *
     * @param iterator  the {@code Iterator} of values to join together, may be null
     * @param separator  the separator character to use
     * @return the joined String, {@code null} if null iterator input
     * @since 2.0
     */
    public static String join(final Iterator<?> iterator, final char separator) {

        // handle null, zero and one elements before building a buffer
        if (iterator == null) {
            return null;
        }
        if (!iterator.hasNext()) {
            return EMPTY;
        }
        final Object first = iterator.next();
        if (!iterator.hasNext()) {
            return Objects.toString(first, EMPTY);
        }

        // two or more elements
        final StringBuilder buf = new StringBuilder(STRING_BUILDER_SIZE); // Java default is 16, probably too small
        if (first != null) {
            buf.append(first);
        }

        while (iterator.hasNext()) {
            buf.append(separator);
            final Object obj = iterator.next();
            if (obj != null) {
                buf.append(obj);
            }
        }

        return buf.toString();
    }

    /**
     * <p>Joins the elements of the provided {@code Iterable} into
     * a single String containing the provided elements.</p>
     *
     * <p>No delimiter is added before or after the list. Null objects or empty
     * strings within the iteration are represented by empty strings.</p>
     *
     * <p>See the examples here: {@link #join(Object[],char)}. </p>
     *
     * @param iterable  the {@code Iterable} providing the values to join together, may be null
     * @param separator  the separator character to use
     * @return the joined String, {@code null} if null iterator input
     * @since 2.3
     */
    public static String join(final Iterable<?> iterable, final char separator) {
        if (iterable == null) {
            return null;
        }
        return join(iterable.iterator(), separator);
    }

    private static StringBuilder newStringBuilder(final int noOfItems) {
        return new StringBuilder(noOfItems * 16);
    }

    /**
     * Convert an InputStream into a String.
     *
     * Highest performing conversion per: https://stackoverflow.com/a/35446009
     *
     * @param inputStream The input stream to be converted.
     * @param charset The decoding charset to use.
     * @return The string value of the input stream, null otherwise.
     * @throws IOException If there are any issues in reading from the stream.
     */
    public static String inputStreamToString(InputStream inputStream, Charset charset) throws IOException {
        if (inputStream != null && inputStream.available() != -1) {
            ByteArrayOutputStream result = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024];
            int length;
            while ((length = inputStream.read(buffer)) != -1) {
                result.write(buffer, 0, length);
            }
            if (charset != null) {
                return result.toString(charset.name());
            }
            return result.toString(StandardCharsets.UTF_8.name());
        }
        return null;
    }

    public static boolean isEmail(String userIdEmail) {
        Matcher matcher = pattern.matcher(userIdEmail);
        return matcher.matches();
    }

    /**
     * Check whether the given {@code String} contains actual <em>text</em>.
     * <p>More specifically, this method returns {@code true} if the
     * {@code String} is not {@code null}, its length is greater than 0,
     * and it contains at least one non-whitespace character.
     * @param str the {@code String} to check (may be {@code null})
     * @return {@code true} if the {@code String} is not {@code null}, its
     * length is greater than 0, and it does not contain whitespace only
     * @see Character#isWhitespace
     */
    public static boolean hasText(String str) {
        return (str != null && !str.isEmpty() && containsText(str));
    }

    private static boolean containsText(CharSequence str) {
        int strLen = str.length();
        for (int i = 0; i < strLen; i++) {
            if (!Character.isWhitespace(str.charAt(i))) {
                return true;
            }
        }
        return false;
    }

    /**
     * Check that the given {@code String} is neither {@code null} nor of length 0.
     * <p>Note: this method returns {@code true} for a {@code String} that
     * purely consists of whitespace.
     * @param str the {@code String} to check (may be {@code null})
     * @return {@code true} if the {@code String} is not {@code null} and has length
     * @see #hasText(String)
     */
    public static boolean hasLength(String str) {
        return (str != null && !str.isEmpty());
    }

    /**
     * Tokenize the given {@code String} into a {@code String} array via a
     * {@link StringTokenizer}.
     * <p>Trims tokens and omits empty tokens.
     * <p>The given {@code delimiters} string can consist of any number of
     * delimiter characters. Each of those characters can be used to separate
     * tokens. A delimiter is always a single character; for multi-character
     * delimiters, consider using delimitedListToStringArray.
     * @param str the {@code String} to tokenize (potentially {@code null} or empty)
     * @param delimiters the delimiter characters, assembled as a {@code String}
     * (each of the characters is individually considered as a delimiter)
     * @return an array of the tokens
     * @see java.util.StringTokenizer
     * @see String#trim()
     */
    public static String[] tokenizeToStringArray(String str, String delimiters) {
        return tokenizeToStringArray(str, delimiters, true, true);
    }

    /**
     * Tokenize the given {@code String} into a {@code String} array via a
     * {@link StringTokenizer}.
     * <p>The given {@code delimiters} string can consist of any number of
     * delimiter characters. Each of those characters can be used to separate
     * tokens. A delimiter is always a single character; for multi-character
     * delimiters, consider using delimitedListToStringArray.
     * @param str the {@code String} to tokenize (potentially {@code null} or empty)
     * @param delimiters the delimiter characters, assembled as a {@code String}
     * (each of the characters is individually considered as a delimiter)
     * @param trimTokens trim the tokens via {@link String#trim()}
     * @param ignoreEmptyTokens omit empty tokens from the result array
     * (only applies to tokens that are empty after trimming; StringTokenizer
     * will not consider subsequent delimiters as token in the first place).
     * @return an array of the tokens
     * @see java.util.StringTokenizer
     * @see String#trim()
     */
    public static String[] tokenizeToStringArray(
            String str, String delimiters, boolean trimTokens, boolean ignoreEmptyTokens) {

        if (str == null) {
            return EMPTY_STRING_ARRAY;
        }

        StringTokenizer st = new StringTokenizer(str, delimiters);
        List<String> tokens = new ArrayList<>();
        while (st.hasMoreTokens()) {
            String token = st.nextToken();
            if (trimTokens) {
                token = token.trim();
            }
            if (!ignoreEmptyTokens || token.length() > 0) {
                tokens.add(token);
            }
        }
        return toStringArray(tokens);
    }

    /**
     * Copy the given {@link Collection} into a {@code String} array.
     * <p>The {@code Collection} must contain {@code String} elements only.
     * @param collection the {@code Collection} to copy
     * (potentially {@code null} or empty)
     * @return the resulting {@code String} array
     */
    public static String[] toStringArray(Collection<String> collection) {
        return (!CollectionUtils.isEmpty(collection) ? collection.toArray(EMPTY_STRING_ARRAY) : EMPTY_STRING_ARRAY);
    }

    /**
     * Convert a {@link Collection} to a delimited {@code String} (e.g. CSV).
     * <p>Useful for {@code toString()} implementations.
     * @param coll the {@code Collection} to convert (potentially {@code null} or empty)
     * @param delim the delimiter to use (typically a ",")
     * @param prefix the {@code String} to start each element with
     * @param suffix the {@code String} to end each element with
     * @return the delimited {@code String}
     */
    public static String collectionToDelimitedString(
            Collection<?> coll, String delim, String prefix, String suffix) {

        if (CollectionUtils.isEmpty(coll)) {
            return "";
        }

        StringBuilder sb = new StringBuilder();
        Iterator<?> it = coll.iterator();
        while (it.hasNext()) {
            sb.append(prefix).append(it.next()).append(suffix);
            if (it.hasNext()) {
                sb.append(delim);
            }
        }
        return sb.toString();
    }

    /**
     * Convert a {@code Collection} into a delimited {@code String} (e.g. CSV).
     * <p>Useful for {@code toString()} implementations.
     * @param coll the {@code Collection} to convert (potentially {@code null} or empty)
     * @param delim the delimiter to use (typically a ",")
     * @return the delimited {@code String}
     */
    public static String collectionToDelimitedString(Collection<?> coll, String delim) {
        return collectionToDelimitedString(coll, delim, "", "");
    }

    /**
     * Convert a {@code Collection} into a delimited {@code String} (e.g., CSV).
     * <p>Useful for {@code toString()} implementations.
     * @param coll the {@code Collection} to convert (potentially {@code null} or empty)
     * @return the delimited {@code String}
     */
    public static String collectionToCommaDelimitedString(Collection<?> coll) {
        return collectionToDelimitedString(coll, ",");
    }

    /**
     * Check if a string is numeric.
     * @param str input
     * @return boolean true is numeric
     */
    public static boolean isNumeric(String str) {
        if (str == null) {
            return false;
        }
        int sz = str.length();
        for (int i = 0; i < sz; i++) {
            if (Character.isDigit(str.charAt(i)) == false) {
                return false;
            }
        }
        return true;
    }

    /**
     * Check if a string is a JWT token.
     * @param str input
     * @return boolean true is jwt
     */
    public static boolean isJwtToken(String str) {
        if (str == null) {
            return false;
        } else {
            // not null
            if(str.indexOf("eyJ") >= 0 && str.indexOf(".") > 0) {
                return true;
            } else {
                return false;
            }
        }
    }

    /**
     * Mask the first half of a string with asterisks for sensitive data before logging.
     * @param str input
     * @return masked string
     */
    public static String maskHalfString(String str) {
        if (str == null) {
            return null;
        } else {
            // not null
            int halfLength = str.length() / 2;
            String masked = "*".repeat(halfLength) + str.substring(halfLength);
            return masked;
        }
    }

    /**
     * Match a URL against an OpenAPI endpoint pattern with curly brackets path parameters
     * @param requestPath the incoming request path
     * @param endpointPattern the OpenAPI endpoint pattern with curly brackets path parameters
     * @return boolean true matched
     */
    public static boolean matchPathToPattern(String requestPath, String endpointPattern) {
        String[] pathPatternParts = endpointPattern.split("/");
        String[] pathParts = requestPath.split("/");

        boolean isMatch = true;
        for (int i = 0; i < pathPatternParts.length; i++) {
            String patternPart = pathPatternParts[i];
            String urlPart = pathParts[i];

            if (patternPart.startsWith("{") && patternPart.endsWith("}")) {
                continue; // Wildcard found, move to the next part
            }

            if (!patternPart.equals(urlPart)) {
                isMatch = false; // Part does not match, URLs do not match
                break;
            }
        }
        return isMatch;
    }
}
