/*
 * This library is part of OpenCms -
 * the Open Source Content Management System
 *
 * Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * For further information about Alkacon Software GmbH & Co. KG, please see the
 * company website: http://www.alkacon.com
 *
 * For further information about OpenCms, please see the
 * project website: http://www.opencms.org
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package org.opencms.util;

import org.opencms.file.CmsResource;
import org.opencms.i18n.CmsEncoder;
import org.opencms.i18n.I_CmsMessageBundle;
import org.opencms.json.JSONException;
import org.opencms.json.JSONObject;
import org.opencms.main.CmsIllegalArgumentException;
import org.opencms.main.CmsLog;
import org.opencms.main.OpenCms;

import java.awt.Color;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import org.apache.commons.logging.Log;
import org.apache.oro.text.perl.MalformedPerl5PatternException;
import org.apache.oro.text.perl.Perl5Util;

import com.cybozu.labs.langdetect.Detector;
import com.cybozu.labs.langdetect.DetectorFactory;
import com.cybozu.labs.langdetect.LangDetectException;
import com.google.common.base.Optional;

/**
 * Provides String utility functions.<p>
 *
 * @since 6.0.0
 */
public final class CmsStringUtil {

    /**
     * Compares two Strings according to the count of containing slashes.<p>
     *
     * If both Strings contain the same count of slashes the Strings are compared.<p>
     */
    public static class CmsSlashComparator implements Comparator<String> {

        /**
         * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
         */
        public int compare(String a, String b) {

            int slashCountA = countChar(a, '/');
            int slashCountB = countChar(b, '/');

            if (slashCountA < slashCountB) {
                return 1;
            } else if (slashCountA == slashCountB) {
                return a.compareTo(b);
            } else {
                return -1;
            }
        }
    }

    /** Regular expression that matches the HTML body end tag. */
    public static final String BODY_END_REGEX = "<\\s*/\\s*body[^>]*>";

    /** Regular expression that matches the HTML body start tag. */
    public static final String BODY_START_REGEX = "<\\s*body[^>]*>";

    /** Constant for <code>"false"</code>. */
    public static final String FALSE = Boolean.toString(false);

    /** a convenient shorthand to the line separator constant. */
    public static final String LINE_SEPARATOR = System.getProperty("line.separator");

    /** Context macro. */
    public static final String MACRO_OPENCMS_CONTEXT = "${OpenCmsContext}";

    /** Pattern to determine a locale for suffixes like '_de' or '_en_US'. */
    public static final Pattern PATTERN_LOCALE_SUFFIX = Pattern.compile(
        "(.*)_([a-z]{2}(?:_[A-Z]{2})?)(?:\\.[^\\.]*)?$");

    /** Pattern to determine the document number for suffixes like '_0001'. */
    public static final Pattern PATTERN_NUMBER_SUFFIX = Pattern.compile("(.*)_(\\d+)(\\.[^\\.^\\n]*)?$");

    /** Pattern matching one or more slashes. */
    public static final Pattern PATTERN_SLASHES = Pattern.compile("/+");

    /** The place holder end sign in the pattern. */
    public static final String PLACEHOLDER_END = "}";

    /** The place holder start sign in the pattern. */
    public static final String PLACEHOLDER_START = "{";

    /** Contains all chars that end a sentence in the {@link #trimToSize(String, int, int, String)} method. */
    public static final char[] SENTENCE_ENDING_CHARS = {'.', '!', '?'};

    /** a convenient shorthand for tabulations.  */
    public static final String TABULATOR = "  ";

    /** Constant for <code>"true"</code>. */
    public static final String TRUE = Boolean.toString(true);

    /** Regex pattern that matches an end body tag. */
    private static final Pattern BODY_END_PATTERN = Pattern.compile(BODY_END_REGEX, Pattern.CASE_INSENSITIVE);

    /** Regex pattern that matches a start body tag. */
    private static final Pattern BODY_START_PATTERN = Pattern.compile(BODY_START_REGEX, Pattern.CASE_INSENSITIVE);

    /** Day constant. */
    private static final long DAYS = 1000 * 60 * 60 * 24;

    /** Hour constant. */
    private static final long HOURS = 1000 * 60 * 60;

    /** The log object for this class. */
    private static final Log LOG = CmsLog.getLog(CmsStringUtil.class);

    /** OpenCms context replace String, static for performance reasons. */
    private static String m_contextReplace;

    /** OpenCms context search String, static for performance reasons. */
    private static String m_contextSearch;

    /** Minute constant. */
    private static final long MINUTES = 1000 * 60;

    /** Second constant. */
    private static final long SECONDS = 1000;

    /** Regex that matches an encoding String in an xml head. */
    private static final Pattern XML_ENCODING_REGEX = Pattern.compile(
        "encoding\\s*=\\s*[\"'].+[\"']",
        Pattern.CASE_INSENSITIVE);

    /** Regex that matches an xml head. */
    private static final Pattern XML_HEAD_REGEX = Pattern.compile("<\\s*\\?.*\\?\\s*>", Pattern.CASE_INSENSITIVE);

    /** Units used for duration parsing. */
    private static final String[] DURATION_UNTIS = {"d", "h", "m", "s", "ms"};

    /** Multipliers used for duration parsing. */
    private static final long[] DURATION_MULTIPLIERS = {24L * 60 * 60 * 1000, 60L * 60 * 1000, 60L * 1000, 1000L, 1L};

    /** Number and unit pattern for duration parsing. */
    private static final Pattern DURATION_NUMBER_AND_UNIT_PATTERN = Pattern.compile("([0-9]+)([a-z]+)");

    /**
     * Default constructor (empty), private because this class has only
     * static methods.<p>
     */
    private CmsStringUtil() {

        // empty
    }

    /**
     * Adds leading and trailing slashes to a path.<p>
     *
     * @param path the path to which add the slashes
     *
     * @return the path with added leading and trailing slashes
     */
    public static String addLeadingAndTrailingSlash(String path) {

        StringBuffer buffer1 = new StringBuffer();
        if (!path.startsWith("/")) {
            buffer1.append("/");
        }
        buffer1.append(path);
        if (!path.endsWith("/")) {
            buffer1.append("/");
        }
        return buffer1.toString();
    }

    /**
     * Returns a string representation for the given array using the given separator.<p>
     *
     * @param arg the array to transform to a String
     * @param separator the item separator
     *
     * @return the String of the given array
     */
    public static String arrayAsString(final String[] arg, String separator) {

        StringBuffer result = new StringBuffer();
        for (int i = 0; i < arg.length; i++) {
            result.append(arg[i]);
            if ((i + 1) < arg.length) {
                result.append(separator);
            }
        }
        return result.toString();
    }

    /**
     * Changes the filename suffix.
     *
     * @param filename the filename to be changed
     * @param suffix the new suffix of the file
     * @return the filename with the replaced suffix
     */
    public static String changeFileNameSuffixTo(String filename, String suffix) {

        int dotPos = filename.lastIndexOf('.');
        if (dotPos != -1) {
            return filename.substring(0, dotPos + 1) + suffix;
        } else {
            // the string has no suffix
            return filename;
        }
    }

    /**
     * Checks if a given name is composed only of the characters <code>a...z,A...Z,0...9</code>
     * and the provided <code>constraints</code>.<p>
     *
     * If the check fails, an Exception is generated. The provided bundle and key is
     * used to generate the Exception. 4 parameters are passed to the Exception:<ol>
     * <li>The <code>name</code>
     * <li>The first illegal character found
     * <li>The position where the illegal character was found
     * <li>The <code>constraints</code></ol>
     *
     * @param name the name to check
     * @param constraints the additional character constraints
     * @param key the key to use for generating the Exception (if required)
     * @param bundle the bundle to use for generating the Exception (if required)
     *
     * @throws CmsIllegalArgumentException if the check fails (generated from the given key and bundle)
     */
    public static void checkName(String name, String constraints, String key, I_CmsMessageBundle bundle)
    throws CmsIllegalArgumentException {

        int l = name.length();
        for (int i = 0; i < l; i++) {
            char c = name.charAt(i);
            if (((c < 'a') || (c > 'z'))
                && ((c < '0') || (c > '9'))
                && ((c < 'A') || (c > 'Z'))
                && (constraints.indexOf(c) < 0)) {

                throw new CmsIllegalArgumentException(
                    bundle.container(key, new Object[] {name, new Character(c), new Integer(i), constraints}));
            }
        }
    }

    /**
     * Returns a string representation for the given collection using the given separator.<p>
     *
     * @param collection the collection to print
     * @param separator the item separator
     *
     * @return the string representation for the given collection
     */
    public static String collectionAsString(Collection<?> collection, String separator) {

        StringBuffer string = new StringBuffer(128);
        Iterator<?> it = collection.iterator();
        while (it.hasNext()) {
            string.append(it.next());
            if (it.hasNext()) {
                string.append(separator);
            }
        }
        return string.toString();
    }

    /**
     * Compares paths while ignoring leading / trailing slashes.<p>
     *
     * @param path1 the first path
     * @param path2 the second path
     * @return true if the paths are equal (ignoring leading or trailing slashes)
     */
    public static boolean comparePaths(String path1, String path2) {

        return addLeadingAndTrailingSlash(path1).equals(addLeadingAndTrailingSlash(path2));
    }

    /**
     * Counts the occurrence of a given char in a given String.<p>
     *
     * @param s the string
     * @param c the char to count
     *
     * @return returns the count of occurrences of a given char in a given String
     */
    public static int countChar(String s, char c) {

        int counter = 0;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == c) {
                counter++;
            }
        }
        return counter;
    }

    /**
     * Returns a String array representation for the given enum.<p>
     *
     * @param <T> the type of the enum
     * @param values the enum values
     *
     * @return the representing String array
     */
    public static <T extends Enum<T>> String[] enumNameToStringArray(T[] values) {

        int i = 0;
        String[] result = new String[values.length];
        for (T value : values) {
            result[i++] = value.name();
        }
        return result;
    }

    /**
     * Replaces occurrences of special control characters in the given input with
     * a HTML representation.<p>
     *
     * This method currently replaces line breaks to <code>&lt;br/&gt;</code> and special HTML chars
     * like <code>&lt; &gt; &amp; &quot;</code> with their HTML entity representation.<p>
     *
     * @param source the String to escape
     *
     * @return the escaped String
     */
    public static String escapeHtml(String source) {

        if (source == null) {
            return null;
        }
        source = CmsEncoder.escapeXml(source);
        source = CmsStringUtil.substitute(source, "\r", "");
        source = CmsStringUtil.substitute(source, "\n", "<br/>\n");
        return source;
    }

    /**
     * Escapes a String so it may be used in JavaScript String definitions.<p>
     *
     * This method replaces line breaks, quotation marks and \ characters.<p>
     *
     * @param source the String to escape
     *
     * @return the escaped String
     */
    public static String escapeJavaScript(String source) {

        source = CmsStringUtil.substitute(source, "\\", "\\\\");
        source = CmsStringUtil.substitute(source, "\"", "\\\"");
        source = CmsStringUtil.substitute(source, "\'", "\\\'");
        source = CmsStringUtil.substitute(source, "\r\n", "\\n");
        source = CmsStringUtil.substitute(source, "\n", "\\n");

        // to avoid XSS (closing script tags) in embedded Javascript
        source = CmsStringUtil.substitute(source, "/", "\\/");
        return source;
    }

    /**
     * Escapes a String so it may be used as a Perl5 regular expression.<p>
     *
     * This method replaces the following characters in a String:<br>
     * <code>{}[]()\$^.*+/</code><p>
     *
     * @param source the string to escape
     *
     * @return the escaped string
     */
    public static String escapePattern(String source) {

        if (source == null) {
            return null;
        }
        StringBuffer result = new StringBuffer(source.length() * 2);
        for (int i = 0; i < source.length(); ++i) {
            char ch = source.charAt(i);
            switch (ch) {
                case '\\':
                    result.append("\\\\");
                    break;
                case '/':
                    result.append("\\/");
                    break;
                case '$':
                    result.append("\\$");
                    break;
                case '^':
                    result.append("\\^");
                    break;
                case '.':
                    result.append("\\.");
                    break;
                case '*':
                    result.append("\\*");
                    break;
                case '+':
                    result.append("\\+");
                    break;
                case '|':
                    result.append("\\|");
                    break;
                case '?':
                    result.append("\\?");
                    break;
                case '{':
                    result.append("\\{");
                    break;
                case '}':
                    result.append("\\}");
                    break;
                case '[':
                    result.append("\\[");
                    break;
                case ']':
                    result.append("\\]");
                    break;
                case '(':
                    result.append("\\(");
                    break;
                case ')':
                    result.append("\\)");
                    break;
                default:
                    result.append(ch);
            }
        }
        return new String(result);
    }

    /**
     * This method takes a part of a html tag definition, an attribute to extend within the
     * given text and a default value for this attribute; and returns a <code>{@link Map}</code>
     * with 2 values: a <code>{@link String}</code> with key <code>"text"</code> with the new text
     * without the given attribute, and another <code>{@link String}</code> with key <code>"value"</code>
     * with the new extended value for the given attribute, this value is surrounded by the same type of
     * quotation marks as in the given text.<p>
     *
     * @param text the text to search in
     * @param attribute the attribute to remove and extend from the text
     * @param defValue a default value for the attribute, should not have any quotation mark
     *
     * @return a map with the new text and the new value for the given attribute
     */
    public static Map<String, String> extendAttribute(String text, String attribute, String defValue) {

        Map<String, String> retValue = new HashMap<String, String>();
        retValue.put("text", text);
        retValue.put("value", "'" + defValue + "'");
        if ((text != null) && (text.toLowerCase().indexOf(attribute.toLowerCase()) >= 0)) {
            // this does not work for things like "att=method()" without quotations.
            String quotation = "\'";
            int pos1 = text.toLowerCase().indexOf(attribute.toLowerCase());
            // looking for the opening quotation mark
            int pos2 = text.indexOf(quotation, pos1);
            int test = text.indexOf("\"", pos1);
            if ((test > -1) && ((pos2 == -1) || (test < pos2))) {
                quotation = "\"";
                pos2 = test;
            }
            // assuming there is a closing quotation mark
            int pos3 = text.indexOf(quotation, pos2 + 1);
            // building the new attribute value
            String newValue = quotation + defValue + text.substring(pos2 + 1, pos3 + 1);
            // removing the onload statement from the parameters
            String newText = text.substring(0, pos1);
            if (pos3 < text.length()) {
                newText += text.substring(pos3 + 1);
            }
            retValue.put("text", newText);
            retValue.put("value", newValue);
        }
        return retValue;
    }

    /**
     * Extracts the content of a <code>&lt;body&gt;</code> tag in a HTML page.<p>
     *
     * This method should be pretty robust and work even if the input HTML does not contains
     * a valid body tag.<p>
     *
     * @param content the content to extract the body from
     *
     * @return the extracted body tag content
     */
    public static String extractHtmlBody(String content) {

        Matcher startMatcher = BODY_START_PATTERN.matcher(content);
        Matcher endMatcher = BODY_END_PATTERN.matcher(content);

        int start = 0;
        int end = content.length();

        if (startMatcher.find()) {
            start = startMatcher.end();
        }

        if (endMatcher.find(start)) {
            end = endMatcher.start();
        }

        return content.substring(start, end);
    }

    /**
     * Extracts the xml encoding setting from an xml file that is contained in a String by parsing
     * the xml head.<p>
     *
     * This is useful if you have a byte array that contains a xml String,
     * but you do not know the xml encoding setting. Since the encoding setting
     * in the xml head is usually encoded with standard US-ASCII, you usually
     * just create a String of the byte array without encoding setting,
     * and use this method to find the 'true' encoding. Then create a String
     * of the byte array again, this time using the found encoding.<p>
     *
     * This method will return <code>null</code> in case no xml head
     * or encoding information is contained in the input.<p>
     *
     * @param content the xml content to extract the encoding from
     *
     * @return the extracted encoding, or null if no xml encoding setting was found in the input
     */
    public static String extractXmlEncoding(String content) {

        String result = null;
        Matcher xmlHeadMatcher = XML_HEAD_REGEX.matcher(content);
        if (xmlHeadMatcher.find()) {
            String xmlHead = xmlHeadMatcher.group();
            Matcher encodingMatcher = XML_ENCODING_REGEX.matcher(xmlHead);
            if (encodingMatcher.find()) {
                String encoding = encodingMatcher.group();
                int pos1 = encoding.indexOf('=') + 2;
                String charset = encoding.substring(pos1, encoding.length() - 1);
                if (Charset.isSupported(charset)) {
                    result = charset;
                }
            }
        }
        return result;
    }

    /**
     * Formats a resource name that it is displayed with the maximum length and path information is adjusted.<p>
     * In order to reduce the length of the displayed names, single folder names are removed/replaced with ... successively,
     * starting with the second! folder. The first folder is removed as last.<p>
     *
     * Example: formatResourceName("/myfolder/subfolder/index.html", 21) returns <code>/myfolder/.../index.html</code>.<p>
     *
     * @param name the resource name to format
     * @param maxLength the maximum length of the resource name (without leading <code>/...</code>)
     *
     * @return the formatted resource name
     */
    public static String formatResourceName(String name, int maxLength) {

        if (name == null) {
            return null;
        }

        if (name.length() <= maxLength) {
            return name;
        }

        int total = name.length();
        String[] names = CmsStringUtil.splitAsArray(name, "/");
        if (name.endsWith("/")) {
            names[names.length - 1] = names[names.length - 1] + "/";
        }
        for (int i = 1; (total > maxLength) && (i < (names.length - 1)); i++) {
            if (i > 1) {
                names[i - 1] = "";
            }
            names[i] = "...";
            total = 0;
            for (int j = 0; j < names.length; j++) {
                int l = names[j].length();
                total += l + ((l > 0) ? 1 : 0);
            }
        }
        if (total > maxLength) {
            names[0] = (names.length > 2) ? "" : (names.length > 1) ? "..." : names[0];
        }

        StringBuffer result = new StringBuffer();
        for (int i = 0; i < names.length; i++) {
            if (names[i].length() > 0) {
                result.append("/");
                result.append(names[i]);
            }
        }

        return result.toString();
    }

    /**
     * Formats a runtime in the format hh:mm:ss, to be used e.g. in reports.<p>
     *
     * If the runtime is greater then 24 hours, the format dd:hh:mm:ss is used.<p>
     *
     * @param runtime the time to format
     *
     * @return the formatted runtime
     */
    public static String formatRuntime(long runtime) {

        long seconds = (runtime / SECONDS) % 60;
        long minutes = (runtime / MINUTES) % 60;
        long hours = (runtime / HOURS) % 24;
        long days = runtime / DAYS;
        StringBuffer strBuf = new StringBuffer();

        if (days > 0) {
            if (days < 10) {
                strBuf.append('0');
            }
            strBuf.append(days);
            strBuf.append(':');
        }

        if (hours < 10) {
            strBuf.append('0');
        }
        strBuf.append(hours);
        strBuf.append(':');

        if (minutes < 10) {
            strBuf.append('0');
        }
        strBuf.append(minutes);
        strBuf.append(':');

        if (seconds < 10) {
            strBuf.append('0');
        }
        strBuf.append(seconds);

        return strBuf.toString();
    }

    /**
     * Returns the color value (<code>{@link Color}</code>) for the given String value.<p>
     *
     * All parse errors are caught and the given default value is returned in this case.<p>
     *
     * @param value the value to parse as color
     * @param defaultValue the default value in case of parsing errors
     * @param key a key to be included in the debug output in case of parse errors
     *
     * @return the int value for the given parameter value String
     */
    public static Color getColorValue(String value, Color defaultValue, String key) {

        Color result;
        try {
            char pre = value.charAt(0);
            if (pre != '#') {
                value = "#" + value;
            }
            result = Color.decode(value);
        } catch (Exception e) {
            if (LOG.isDebugEnabled()) {
                LOG.debug(Messages.get().getBundle().key(Messages.ERR_UNABLE_TO_PARSE_COLOR_2, value, key));
            }
            result = defaultValue;
        }
        return result;
    }

    /**
     * Gets the common prefix path of two paths.<p>
     *
     * @param first the first path
     * @param second the second path
     *
     * @return the common prefix path
     */
    public static String getCommonPrefixPath(String first, String second) {

        List<String> firstComponents = getPathComponents(first);
        List<String> secondComponents = getPathComponents(second);
        int minSize = Math.min(firstComponents.size(), secondComponents.size());
        StringBuffer resultBuffer = new StringBuffer();
        for (int i = 0; i < minSize; i++) {
            if (firstComponents.get(i).equals(secondComponents.get(i))) {
                resultBuffer.append("/");
                resultBuffer.append(firstComponents.get(i));
            } else {
                break;
            }
        }
        String result = resultBuffer.toString();
        if (result.length() == 0) {
            result = "/";
        }
        return result;
    }

    /**
     * Returns the Ethernet-Address of the locale host.<p>
     *
     * A dummy ethernet address is returned, if the ip is
     * representing the loopback address or in case of exceptions.<p>
     *
     * @return the Ethernet-Address
     */
    public static String getEthernetAddress() {

        try {
            InetAddress ip = InetAddress.getLocalHost();
            if (!ip.isLoopbackAddress()) {
                NetworkInterface network = NetworkInterface.getByInetAddress(ip);
                byte[] mac = network.getHardwareAddress();
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < mac.length; i++) {
                    sb.append(String.format("%02X%s", new Byte(mac[i]), (i < (mac.length - 1)) ? ":" : ""));
                }
                return sb.toString();
            }
        } catch (Throwable t) {
            // if an exception occurred return a dummy address
        }
        // return a dummy ethernet address, if the ip is representing the loopback address or in case of exceptions
        return CmsUUID.getDummyEthernetAddress();
    }

    /**
     * Returns the Integer (int) value for the given String value.<p>
     *
     * All parse errors are caught and the given default value is returned in this case.<p>
     *
     * @param value the value to parse as int
     * @param defaultValue the default value in case of parsing errors
     * @param key a key to be included in the debug output in case of parse errors
     *
     * @return the int value for the given parameter value String
     */
    public static int getIntValue(String value, int defaultValue, String key) {

        int result;
        try {
            result = Integer.valueOf(value).intValue();
        } catch (Exception e) {
            if (LOG.isDebugEnabled()) {
                LOG.debug(Messages.get().getBundle().key(Messages.ERR_UNABLE_TO_PARSE_INT_2, value, key));
            }
            result = defaultValue;
        }
        return result;
    }

    /**
     * Returns the closest Integer (int) value for the given String value.<p>
     *
     * All parse errors are caught and the given default value is returned in this case.<p>
     *
     * @param value the value to parse as int, can also represent a float value
     * @param defaultValue the default value in case of parsing errors
     * @param key a key to be included in the debug output in case of parse errors
     *
     * @return the closest int value for the given parameter value String
     */
    public static int getIntValueRounded(String value, int defaultValue, String key) {

        int result;
        try {
            result = Math.round(Float.parseFloat(value));
        } catch (Exception e) {
            if (LOG.isDebugEnabled()) {
                LOG.debug(Messages.get().getBundle().key(Messages.ERR_UNABLE_TO_PARSE_INT_2, value, key));
            }
            result = defaultValue;
        }
        return result;
    }

    /**
     * Returns the locale by suffix for the given name, including optional country code.<p>
     *
     * Calls {@link CmsResource#getName(String)} first, so the given name can also be a resource root path.<p>
     *
     * @param name the name to get the locale for
     *
     * @return the locale, or <code>null</code>
     *
     * @see #getLocaleSuffixForName(String)
     */
    public static Locale getLocaleForName(String name) {

        String suffix = getLocaleSuffixForName(CmsResource.getName(name));
        if (suffix != null) {
            String laguageString = suffix.substring(0, 2);
            return suffix.length() == 5 ? new Locale(laguageString, suffix.substring(3, 5)) : new Locale(laguageString);
        }
        return null;
    }

    /**
     * Returns the locale for the given text based on the language detection library.<p>
     *
     * The result will be <code>null</code> if the detection fails or the detected locale is not configured
     * in the 'opencms-system.xml' as available locale.<p>
     *
     * @param text the text to retrieve the locale for
     *
     * @return the detected locale for the given text
     */
    public static Locale getLocaleForText(String text) {

        // try to detect locale by language detector
        if (isNotEmptyOrWhitespaceOnly(text)) {
            try {
                Detector detector = DetectorFactory.create();
                detector.append(text);
                String lang = detector.detect();
                Locale loc = new Locale(lang);
                if (OpenCms.getLocaleManager().getAvailableLocales().contains(loc)) {
                    return loc;
                }
            } catch (LangDetectException e) {
                LOG.debug(e);
            }
        }
        return null;
    }

    /**
     * Returns the locale suffix as String for a given name, <code>null</code> otherwise.<p>
     *
     * Uses the the {@link #PATTERN_LOCALE_SUFFIX} to find a language_country occurrence in the
     * given name and returns the first group of the match.<p>
     *
     * <b>Examples:</b>
     *
     * <ul>
     * <li><code>rabbit_en_EN.html -> Locale[en_EN]</code>
     * <li><code>rabbit_en_EN&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-> Locale[en_EN]</code>
     * <li><code>rabbit_en.html&nbsp;&nbsp;&nbsp;&nbsp;-> Locale[en]</code>
     * <li><code>rabbit_en&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-> Locale[en]</code>
     * <li><code>rabbit_en.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-> Locale[en]</code>
     * <li><code>rabbit_enr&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-> null</code>
     * <li><code>rabbit_en.tar.gz&nbsp;&nbsp;-> null</code>
     * </ul>
     *
     * @param name the resource name to get the locale suffix for
     *
     * @return the locale suffix if found, <code>null</code> otherwise
     */
    public static String getLocaleSuffixForName(String name) {

        Matcher matcher = PATTERN_LOCALE_SUFFIX.matcher(name);
        if (matcher.find()) {
            return matcher.group(2);
        }
        return null;
    }

    /**
     * Returns the Long (long) value for the given String value.<p>
     *
     * All parse errors are caught and the given default value is returned in this case.<p>
     *
     * @param value the value to parse as long
     * @param defaultValue the default value in case of parsing errors
     * @param key a key to be included in the debug output in case of parse errors
     *
     * @return the long value for the given parameter value String
     */
    public static long getLongValue(String value, long defaultValue, String key) {

        long result;
        try {
            result = Long.valueOf(value).longValue();
        } catch (Exception e) {
            if (LOG.isDebugEnabled()) {
                LOG.debug(Messages.get().getBundle().key(Messages.ERR_UNABLE_TO_PARSE_INT_2, value, key));
            }
            result = defaultValue;
        }
        return result;
    }

    /**
     * Splits a path into its non-empty path components.<p>
     *
     * If the path is the root path, an empty list will be returned.<p>
     *
     * @param path the path to split
     *
     * @return the list of non-empty path components
     */
    public static List<String> getPathComponents(String path) {

        List<String> result = CmsStringUtil.splitAsList(path, "/");
        Iterator<String> iter = result.iterator();
        while (iter.hasNext()) {
            String token = iter.next();
            if (CmsStringUtil.isEmptyOrWhitespaceOnly(token)) {
                iter.remove();
            }
        }
        return result;
    }

    /**
     * Converts a given path to a path relative to a base folder, but only if it actually is a sub-path of the latter, otherwise null is returned.<p>
     *
     * @param base the base path
     * @param path the path which should be converted to a relative path
     *
     * @return 'path' converted to a path relative to 'base', or null if 'path' is not a sub-folder of 'base'
     */
    public static String getRelativeSubPath(String base, String path) {

        String result = null;
        base = CmsStringUtil.joinPaths(base, "/");
        path = CmsStringUtil.joinPaths(path, "/");
        if (path.startsWith(base)) {
            result = path.substring(base.length());
        }
        if (result != null) {
            if (result.endsWith("/")) {
                result = result.substring(0, result.length() - 1);
            }
            if (!result.startsWith("/")) {
                result = "/" + result;
            }
        }
        return result;
    }

    /**
     * Returns <code>true</code> if the provided String is either <code>null</code>
     * or the empty String <code>""</code>.<p>
     *
     * @param value the value to check
     *
     * @return true, if the provided value is null or the empty String, false otherwise
     */
    public static boolean isEmpty(String value) {

        return (value == null) || (value.length() == 0);
    }

    /**
     * Returns <code>true</code> if the provided String is either <code>null</code>
     * or contains only white spaces.<p>
     *
     * @param value the value to check
     *
     * @return true, if the provided value is null or contains only white spaces, false otherwise
     */
    public static boolean isEmptyOrWhitespaceOnly(String value) {

        return isEmpty(value) || (value.trim().length() == 0);
    }

    /**
     * Returns <code>true</code> if the provided Objects are either both <code>null</code>
     * or equal according to {@link Object#equals(Object)}.<p>
     *
     * @param value1 the first object to compare
     * @param value2 the second object to compare
     *
     * @return <code>true</code> if the provided Objects are either both <code>null</code>
     *              or equal according to {@link Object#equals(Object)}
     */
    public static boolean isEqual(Object value1, Object value2) {

        if (value1 == null) {
            return (value2 == null);
        }
        return value1.equals(value2);
    }

    /**
     * Returns <code>true</code> if the provided String is neither <code>null</code>
     * nor the empty String <code>""</code>.<p>
     *
     * @param value the value to check
     *
     * @return true, if the provided value is not null and not the empty String, false otherwise
     */
    public static boolean isNotEmpty(String value) {

        return (value != null) && (value.length() != 0);
    }

    /**
     * Returns <code>true</code> if the provided String is neither <code>null</code>
     * nor contains only white spaces.<p>
     *
     * @param value the value to check
     *
     * @return <code>true</code>, if the provided value is <code>null</code>
     *          or contains only white spaces, <code>false</code> otherwise
     */
    public static boolean isNotEmptyOrWhitespaceOnly(String value) {

        return (value != null) && (value.trim().length() > 0);
    }

    /**
     * Checks whether one path is a prefix path of another, i.e. its path components are
     * the initial path components of the second path.<p>
     *
     * It is not enough to just use {@link String#startsWith}, because we want /foo/bar to
     * be a prefix path of  /foo/bar/baz, but not of /foo/bar42.<p>
     *
     * @param firstPath the first path
     * @param secondPath the second path
     *
     * @return true if the first path is a prefix path of the second path
     */
    public static boolean isPrefixPath(String firstPath, String secondPath) {

        firstPath = CmsStringUtil.joinPaths(firstPath, "/");
        secondPath = CmsStringUtil.joinPaths(secondPath, "/");
        return secondPath.startsWith(firstPath);
    }

    /**
     * Checks if the given class name is a valid Java class name.<p>
     *
     * @param className the name to check
     *
     * @return true if the given class name is a valid Java class name
     */
    public static boolean isValidJavaClassName(String className) {

        if (CmsStringUtil.isEmpty(className)) {
            return false;
        }
        int length = className.length();
        boolean nodot = true;
        for (int i = 0; i < length; i++) {
            char ch = className.charAt(i);
            if (nodot) {
                if (ch == '.') {
                    return false;
                } else if (Character.isJavaIdentifierStart(ch)) {
                    nodot = false;
                } else {
                    return false;
                }
            } else {
                if (ch == '.') {
                    nodot = true;
                } else if (Character.isJavaIdentifierPart(ch)) {
                    nodot = false;
                } else {
                    return false;
                }
            }
        }
        return true;
    }

    /**
     * Concatenates multiple paths and separates them with '/'.<p>
     *
     * Consecutive slashes will be reduced to a single slash in the resulting string.
     * For example, joinPaths("/foo/", "/bar", "baz") will return "/foo/bar/baz".
     *
     * @param paths the list of paths
     *
     * @return the joined path
     */
    public static String joinPaths(List<String> paths) {

        String result = listAsString(paths, "/");
        // result may now contain multiple consecutive slashes, so reduce them to single slashes
        result = PATTERN_SLASHES.matcher(result).replaceAll("/");
        return result;
    }

    /**
     * Concatenates multiple paths and separates them with '/'.<p>
     *
     * Consecutive slashes will be reduced to a single slash in the resulting string.
     * For example joinPaths("/foo/", "/bar", "baz") will return "/foo/bar/baz".<p>
     *
     * If one of the argument paths already contains a double "//" this will also be reduced to '/'.
     * For example joinPaths("/foo//bar/", "/baz") will return "/foo/bar/baz".
     *
     * @param paths the array of paths
     *
     * @return the joined path
     */
    public static String joinPaths(String... paths) {

        StringBuffer result = new StringBuffer(paths.length * 32);
        boolean noSlash = true;
        for (int i = 0; i < paths.length; i++) {
            for (int j = 0; j < paths[i].length(); j++) {
                char c = paths[i].charAt(j);
                if (c != '/') {
                    result.append(c);
                    noSlash = true;
                } else if (noSlash) {
                    result.append('/');
                    noSlash = false;
                }
            }
            if (noSlash && (i < (paths.length - 1))) {
                result.append('/');
                noSlash = false;
            }
        }
        return result.toString();
    }

    /**
     * Returns the last index of any of the given chars in the given source.<p>
     *
     * If no char is found, -1 is returned.<p>
     *
     * @param source the source to check
     * @param chars the chars to find
     *
     * @return the last index of any of the given chars in the given source, or -1
     */
    public static int lastIndexOf(String source, char[] chars) {

        // now try to find an "sentence ending" char in the text in the "findPointArea"
        int result = -1;
        for (int i = 0; i < chars.length; i++) {
            int pos = source.lastIndexOf(chars[i]);
            if (pos > result) {
                // found new last char
                result = pos;
            }
        }
        return result;
    }

    /**
     * Returns the last index a whitespace char the given source.<p>
     *
     * If no whitespace char is found, -1 is returned.<p>
     *
     * @param source the source to check
     *
     * @return the last index a whitespace char the given source, or -1
     */
    public static int lastWhitespaceIn(String source) {

        if (CmsStringUtil.isEmpty(source)) {
            return -1;
        }
        int pos = -1;
        for (int i = source.length() - 1; i >= 0; i--) {
            if (Character.isWhitespace(source.charAt(i))) {
                pos = i;
                break;
            }
        }
        return pos;
    }

    /**
     * Returns a string representation for the given list using the given separator.<p>
     *
     * @param list the list to write
     * @param separator the item separator string
     *
     * @return the string representation for the given map
     */
    public static String listAsString(List<?> list, String separator) {

        StringBuffer string = new StringBuffer(128);
        Iterator<?> it = list.iterator();
        while (it.hasNext()) {
            string.append(it.next());
            if (it.hasNext()) {
                string.append(separator);
            }
        }
        return string.toString();
    }

    /**
     * Encodes a map with string keys and values as a JSON string with the same keys/values.<p>
     *
     * @param map the input map
     * @return the JSON data containing the map entries
     */
    public static String mapAsJson(Map<String, String> map) {

        JSONObject obj = new JSONObject();
        for (Map.Entry<String, String> entry : map.entrySet()) {
            try {
                obj.put(entry.getKey(), entry.getValue());
            } catch (JSONException e) {
                LOG.error(e.getLocalizedMessage(), e);
            }
        }
        return obj.toString();
    }

    /**
     * Returns a string representation for the given map using the given separators.<p>
     *
     * @param <K> type of map keys
     * @param <V> type of map values
     * @param map the map to write
     * @param sepItem the item separator string
     * @param sepKeyval the key-value pair separator string
     *
     * @return the string representation for the given map
     */
    public static <K, V> String mapAsString(Map<K, V> map, String sepItem, String sepKeyval) {

        StringBuffer string = new StringBuffer(128);
        Iterator<Map.Entry<K, V>> it = map.entrySet().iterator();
        while (it.hasNext()) {
            Map.Entry<K, V> entry = it.next();
            string.append(entry.getKey());
            string.append(sepKeyval);
            string.append(entry.getValue());
            if (it.hasNext()) {
                string.append(sepItem);
            }
        }
        return string.toString();
    }

    /**
     * Applies white space padding to the left of the given String.<p>
     *
     * @param input the input to pad left
     * @param size the size of the padding
     *
     * @return the input padded to the left
     */
    public static String padLeft(String input, int size) {

        return (new PrintfFormat("%" + size + "s")).sprintf(input);
    }

    /**
     * Applies white space padding to the right of the given String.<p>
     *
     * @param input the input to pad right
     * @param size the size of the padding
     *
     * @return the input padded to the right
     */
    public static String padRight(String input, int size) {

        return (new PrintfFormat("%-" + size + "s")).sprintf(input);
    }

    /**
     * Parses a duration and returns the corresponding number of milliseconds.
     *
     * Durations consist of a space-separated list of components of the form {number}{time unit},
     * for example 1d 5m. The available units are d (days), h (hours), m (months), s (seconds), ms (milliseconds).<p>
     *
     * @param durationStr the duration string
     * @param defaultValue the default value to return in case the pattern does not match
     * @return the corresponding number of milliseconds
     */
    public static final long parseDuration(String durationStr, long defaultValue) {

        durationStr = durationStr.toLowerCase().trim();
        Matcher matcher = DURATION_NUMBER_AND_UNIT_PATTERN.matcher(durationStr);
        long millis = 0;
        boolean matched = false;
        while (matcher.find()) {
            long number = Long.valueOf(matcher.group(1)).longValue();
            String unit = matcher.group(2);
            long multiplier = 0;
            for (int j = 0; j < DURATION_UNTIS.length; j++) {
                if (unit.equals(DURATION_UNTIS[j])) {
                    multiplier = DURATION_MULTIPLIERS[j];
                    break;
                }
            }
            if (multiplier == 0) {
                LOG.warn("parseDuration: Unknown unit " + unit);
            } else {
                matched = true;
            }
            millis += number * multiplier;
        }
        if (!matched) {
            millis = defaultValue;
        }
        return millis;
    }

    /**
     * Replaces a constant prefix with another string constant in a given text.<p>
     *
     * If the input string does not start with the given prefix, Optional.absent() is returned.<p>
     *
     * @param text the text for which to replace the prefix
     * @param origPrefix the original prefix
     * @param newPrefix the replacement prefix
     * @param ignoreCase if true, upper-/lower case differences will be ignored
     *
     * @return an Optional containing either the string with the replaced prefix, or an absent value if the prefix could not be replaced
     */
    public static Optional<String> replacePrefix(String text, String origPrefix, String newPrefix, boolean ignoreCase) {

        String prefixTestString = ignoreCase ? text.toLowerCase() : text;
        origPrefix = ignoreCase ? origPrefix.toLowerCase() : origPrefix;
        if (prefixTestString.startsWith(origPrefix)) {
            return Optional.of(newPrefix + text.substring(origPrefix.length()));
        } else {
            return Optional.absent();
        }
    }

    /**
     * Splits a String into substrings along the provided char delimiter and returns
     * the result as an Array of Substrings.<p>
     *
     * @param source the String to split
     * @param delimiter the delimiter to split at
     *
     * @return the Array of splitted Substrings
     */
    public static String[] splitAsArray(String source, char delimiter) {

        List<String> result = splitAsList(source, delimiter);
        return result.toArray(new String[result.size()]);
    }

    /**
     * Splits a String into substrings along the provided String delimiter and returns
     * the result as an Array of Substrings.<p>
     *
     * @param source the String to split
     * @param delimiter the delimiter to split at
     *
     * @return the Array of splitted Substrings
     */
    public static String[] splitAsArray(String source, String delimiter) {

        List<String> result = splitAsList(source, delimiter);
        return result.toArray(new String[result.size()]);
    }

    /**
     * Splits a String into substrings along the provided char delimiter and returns
     * the result as a List of Substrings.<p>
     *
     * @param source the String to split
     * @param delimiter the delimiter to split at
     *
     * @return the List of splitted Substrings
     */
    public static List<String> splitAsList(String source, char delimiter) {

        return splitAsList(source, delimiter, false);
    }

    /**
     * Splits a String into substrings along the provided char delimiter and returns
     * the result as a List of Substrings.<p>
     *
     * @param source the String to split
     * @param delimiter the delimiter to split at
     * @param trim flag to indicate if leading and trailing white spaces should be omitted
     *
     * @return the List of splitted Substrings
     */
    public static List<String> splitAsList(String source, char delimiter, boolean trim) {

        List<String> result = new ArrayList<String>();
        int i = 0;
        int l = source.length();
        int n = source.indexOf(delimiter);
        while (n != -1) {
            // zero - length items are not seen as tokens at start or end
            if ((i < n) || ((i > 0) && (i < l))) {
                result.add(trim ? source.substring(i, n).trim() : source.substring(i, n));
            }
            i = n + 1;
            n = source.indexOf(delimiter, i);
        }
        // is there a non - empty String to cut from the tail?
        if (n < 0) {
            n = source.length();
        }
        if (i < n) {
            result.add(trim ? source.substring(i).trim() : source.substring(i));
        }
        return result;
    }

    /**
     * Splits a String into substrings along the provided String delimiter and returns
     * the result as List of Substrings.<p>
     *
     * @param source the String to split
     * @param delimiter the delimiter to split at
     *
     * @return the Array of splitted Substrings
     */
    public static List<String> splitAsList(String source, String delimiter) {

        return splitAsList(source, delimiter, false);
    }

    /**
     * Splits a String into substrings along the provided String delimiter and returns
     * the result as List of Substrings.<p>
     *
     * @param source the String to split
     * @param delimiter the delimiter to split at
     * @param trim flag to indicate if leading and trailing white spaces should be omitted
     *
     * @return the Array of splitted Substrings
     */
    public static List<String> splitAsList(String source, String delimiter, boolean trim) {

        int dl = delimiter.length();
        if (dl == 1) {
            // optimize for short strings
            return splitAsList(source, delimiter.charAt(0), trim);
        }

        List<String> result = new ArrayList<String>();
        int i = 0;
        int l = source.length();
        int n = source.indexOf(delimiter);
        while (n != -1) {
            // zero - length items are not seen as tokens at start or end:  ",," is one empty token but not three
            if ((i < n) || ((i > 0) && (i < l))) {
                result.add(trim ? source.substring(i, n).trim() : source.substring(i, n));
            }
            i = n + dl;
            n = source.indexOf(delimiter, i);
        }
        // is there a non - empty String to cut from the tail?
        if (n < 0) {
            n = source.length();
        }
        if (i < n) {
            result.add(trim ? source.substring(i).trim() : source.substring(i));
        }
        return result;
    }

    /**
     * Splits a String into substrings along the provided <code>paramDelim</code> delimiter,
     * then each substring is treat as a key-value pair delimited by <code>keyValDelim</code>.<p>
     *
     * @param source the string to split
     * @param paramDelim the string to delimit each key-value pair
     * @param keyValDelim the string to delimit key and value
     *
     * @return a map of splitted key-value pairs
     */
    public static Map<String, String> splitAsMap(String source, String paramDelim, String keyValDelim) {

        int keyValLen = keyValDelim.length();
        // use LinkedHashMap to preserve the order of items
        Map<String, String> params = new LinkedHashMap<String, String>();
        Iterator<String> itParams = CmsStringUtil.splitAsList(source, paramDelim, true).iterator();
        while (itParams.hasNext()) {
            String param = itParams.next();
            int pos = param.indexOf(keyValDelim);
            String key = param;
            String value = "";
            if (pos > 0) {
                key = param.substring(0, pos);
                if ((pos + keyValLen) < param.length()) {
                    value = param.substring(pos + keyValLen);
                }
            }
            params.put(key, value);
        }
        return params;
    }

    /**
     * Substitutes a pattern in a string using a {@link I_CmsRegexSubstitution}.<p>
     *
     * @param pattern the pattern to substitute
     * @param text the text in which the pattern should be substituted
     * @param sub the substitution handler
     *
     * @return the transformed string
     */
    public static String substitute(Pattern pattern, String text, I_CmsRegexSubstitution sub) {

        StringBuffer buffer = new StringBuffer();
        Matcher matcher = pattern.matcher(text);
        while (matcher.find()) {
            matcher.appendReplacement(buffer, sub.substituteMatch(text, matcher));
        }
        matcher.appendTail(buffer);
        return buffer.toString();
    }

    /**
     * Replaces a set of <code>searchString</code> and <code>replaceString</code> pairs,
     * given by the <code>substitutions</code> Map parameter.<p>
     *
     * @param source the string to scan
     * @param substitions the map of substitutions
     *
     * @return the substituted String
     *
     * @see #substitute(String, String, String)
     */
    public static String substitute(String source, Map<String, String> substitions) {

        String result = source;
        Iterator<Map.Entry<String, String>> it = substitions.entrySet().iterator();
        while (it.hasNext()) {
            Map.Entry<String, String> entry = it.next();
            result = substitute(result, entry.getKey(), entry.getValue().toString());
        }
        return result;
    }

    /**
     * Substitutes <code>searchString</code> in the given source String with <code>replaceString</code>.<p>
     *
     * This is a high-performance implementation which should be used as a replacement for
     * <code>{@link String#replaceAll(java.lang.String, java.lang.String)}</code> in case no
     * regular expression evaluation is required.<p>
     *
     * @param source the content which is scanned
     * @param searchString the String which is searched in content
     * @param replaceString the String which replaces <code>searchString</code>
     *
     * @return the substituted String
     */
    public static String substitute(String source, String searchString, String replaceString) {

        if (source == null) {
            return null;
        }

        if (isEmpty(searchString)) {
            return source;
        }

        if (replaceString == null) {
            replaceString = "";
        }
        int len = source.length();
        int sl = searchString.length();
        int rl = replaceString.length();
        int length;
        if (sl == rl) {
            length = len;
        } else {
            int c = 0;
            int s = 0;
            int e;
            while ((e = source.indexOf(searchString, s)) != -1) {
                c++;
                s = e + sl;
            }
            if (c == 0) {
                return source;
            }
            length = len - (c * (sl - rl));
        }

        int s = 0;
        int e = source.indexOf(searchString, s);
        if (e == -1) {
            return source;
        }
        StringBuffer sb = new StringBuffer(length);
        while (e != -1) {
            sb.append(source.substring(s, e));
            sb.append(replaceString);
            s = e + sl;
            e = source.indexOf(searchString, s);
        }
        e = len;
        sb.append(source.substring(s, e));
        return sb.toString();
    }

    /**
     * Substitutes the OpenCms context path (e.g. /opencms/opencms/) in a HTML page with a
     * special variable so that the content also runs if the context path of the server changes.<p>
     *
     * @param htmlContent the HTML to replace the context path in
     * @param context the context path of the server
     *
     * @return the HTML with the replaced context path
     */
    public static String substituteContextPath(String htmlContent, String context) {

        if (m_contextSearch == null) {
            m_contextSearch = "([^\\w/])" + context;
            m_contextReplace = "$1" + CmsStringUtil.escapePattern(CmsStringUtil.MACRO_OPENCMS_CONTEXT) + "/";
        }
        return substitutePerl(htmlContent, m_contextSearch, m_contextReplace, "g");
    }

    /**
     * Substitutes searchString in content with replaceItem.<p>
     *
     * @param content the content which is scanned
     * @param searchString the String which is searched in content
     * @param replaceItem the new String which replaces searchString
     * @param occurences must be a "g" if all occurrences of searchString shall be replaced
     *
     * @return String the substituted String
     */
    public static String substitutePerl(String content, String searchString, String replaceItem, String occurences) {

        String translationRule = "s#" + searchString + "#" + replaceItem + "#" + occurences;
        Perl5Util perlUtil = new Perl5Util();
        try {
            return perlUtil.substitute(translationRule, content);
        } catch (MalformedPerl5PatternException e) {
            if (LOG.isDebugEnabled()) {
                LOG.debug(
                    Messages.get().getBundle().key(Messages.LOG_MALFORMED_TRANSLATION_RULE_1, translationRule),
                    e);
            }
        }
        return content;
    }

    /**
     * Returns the java String literal for the given String. <p>
     *
     * This is the form of the String that had to be written into source code
     * using the unicode escape sequence for special characters. <p>
     *
     * Example: "&Auml" would be transformed to "\\u00C4".<p>
     *
     * @param s a string that may contain non-ascii characters
     *
     * @return the java unicode escaped string Literal of the given input string
     */
    public static String toUnicodeLiteral(String s) {

        StringBuffer result = new StringBuffer();
        char[] carr = s.toCharArray();

        String unicode;
        for (int i = 0; i < carr.length; i++) {
            result.append("\\u");
            // append leading zeros
            unicode = Integer.toHexString(carr[i]).toUpperCase();
            for (int j = 4 - unicode.length(); j > 0; j--) {
                result.append("0");
            }
            result.append(unicode);
        }
        return result.toString();
    }

    /**
     * This method transformes a string which matched a format with one or more place holders into another format. The
     * other format also includes the same number of place holders. Place holders start with
     * {@link org.opencms.util.CmsStringUtil#PLACEHOLDER_START} and end with {@link org.opencms.util.CmsStringUtil#PLACEHOLDER_END}.<p>
     *
     * @param oldFormat the original format
     * @param newFormat the new format
     * @param value the value which matched the original format and which shall be transformed into the new format
     *
     * @return the new value with the filled place holder with the information in the parameter value
     */
    public static String transformValues(String oldFormat, String newFormat, String value) {

        if (!oldFormat.contains(CmsStringUtil.PLACEHOLDER_START)
            || !oldFormat.contains(CmsStringUtil.PLACEHOLDER_END)
            || !newFormat.contains(CmsStringUtil.PLACEHOLDER_START)
            || !newFormat.contains(CmsStringUtil.PLACEHOLDER_END)) {
            // no place holders are set in correct format
            // that is why there is nothing to calculate and the value is the new format
            return newFormat;
        }
        //initialize the arrays with the values where the place holders starts
        ArrayList<Integer> oldValues = new ArrayList<Integer>();
        ArrayList<Integer> newValues = new ArrayList<Integer>();

        // count the number of placeholders
        // for example these are three pairs:
        // old format: {.*}<b>{.*}</b>{.*}
        // new format: {}<strong>{}</strong>{}
        // get the number of place holders in the old format
        int oldNumber = 0;
        try {
            int counter = 0;
            Pattern pattern = Pattern.compile("\\{\\.\\*\\}");
            Matcher matcher = pattern.matcher(oldFormat);
            // get the number of matches
            while (matcher.find()) {
                counter += 1;
            }
            oldValues = new ArrayList<Integer>(counter);
            matcher = pattern.matcher(oldFormat);
            while (matcher.find()) {
                int start = matcher.start() + 1;
                oldValues.add(oldNumber, new Integer(start));
                oldNumber += 1;
            }
        } catch (PatternSyntaxException e) {
            // do nothing
        }
        // get the number of place holders in the new format
        int newNumber = 0;
        try {
            int counter = 0;
            Pattern pattern = Pattern.compile("\\{\\}");
            Matcher matcher = pattern.matcher(newFormat);
            // get the number of matches
            while (matcher.find()) {
                counter += 1;
            }
            newValues = new ArrayList<Integer>(counter);
            matcher = pattern.matcher(newFormat);
            while (matcher.find()) {
                int start = matcher.start() + 1;
                newValues.add(newNumber, new Integer(start));
                newNumber += 1;
            }
        } catch (PatternSyntaxException e) {
            // do nothing
        }
        // prove the numbers of place holders
        if (oldNumber != newNumber) {
            // not the same number of place holders in the old and in the new format
            return newFormat;
        }

        // initialize the arrays with the values between the place holders
        ArrayList<String> oldBetween = new ArrayList<String>(oldNumber + 1);
        ArrayList<String> newBetween = new ArrayList<String>(newNumber + 1);

        // get the values between the place holders for the old format
        // for this example with oldFormat: {.*}<b>{.*}</b>{.*}
        // this array is that:
        // ---------
        // | empty |
        // ---------
        // | <b>   |
        // |--------
        // | </b>  |
        // |--------
        // | empty |
        // |--------
        int counter = 0;
        Iterator<Integer> iter = oldValues.iterator();
        while (iter.hasNext()) {
            int start = iter.next().intValue();
            if (counter == 0) {
                // the first entry
                if (start == 1) {
                    // the first place holder starts at the beginning of the old format
                    // for example: {.*}<b>...
                    oldBetween.add(counter, "");
                } else {
                    // the first place holder starts NOT at the beginning of the old format
                    // for example: <a>{.*}<b>...
                    String part = oldFormat.substring(0, start - 1);
                    oldBetween.add(counter, part);
                }
            } else {
                // the entries between the first and the last entry
                int lastStart = oldValues.get(counter - 1).intValue();
                String part = oldFormat.substring(lastStart + 3, start - 1);
                oldBetween.add(counter, part);
            }
            counter += 1;
        }
        // the last element
        int lastElstart = oldValues.get(counter - 1).intValue();
        if ((lastElstart + 2) == (oldFormat.length() - 1)) {
            // the last place holder ends at the end of the old format
            // for example: ...</b>{.*}
            oldBetween.add(counter, "");
        } else {
            // the last place holder ends NOT at the end of the old format
            // for example: ...</b>{.*}</a>
            String part = oldFormat.substring(lastElstart + 3);
            oldBetween.add(counter, part);
        }

        // get the values between the place holders for the new format
        // for this example with newFormat: {}<strong>{}</strong>{}
        // this array is that:
        // ------------|
        // | empty     |
        // ------------|
        // | <strong>  |
        // |-----------|
        // | </strong> |
        // |-----------|
        // | empty     |
        // |-----------|
        counter = 0;
        iter = newValues.iterator();
        while (iter.hasNext()) {
            int start = iter.next().intValue();
            if (counter == 0) {
                // the first entry
                if (start == 1) {
                    // the first place holder starts at the beginning of the new format
                    // for example: {.*}<b>...
                    newBetween.add(counter, "");
                } else {
                    // the first place holder starts NOT at the beginning of the new format
                    // for example: <a>{.*}<b>...
                    String part = newFormat.substring(0, start - 1);
                    newBetween.add(counter, part);
                }
            } else {
                // the entries between the first and the last entry
                int lastStart = newValues.get(counter - 1).intValue();
                String part = newFormat.substring(lastStart + 1, start - 1);
                newBetween.add(counter, part);
            }
            counter += 1;
        }
        // the last element
        lastElstart = newValues.get(counter - 1).intValue();
        if ((lastElstart + 2) == (newFormat.length() - 1)) {
            // the last place holder ends at the end of the old format
            // for example: ...</b>{.*}
            newBetween.add(counter, "");
        } else {
            // the last place holder ends NOT at the end of the old format
            // for example: ...</b>{.*}</a>
            String part = newFormat.substring(lastElstart + 1);
            newBetween.add(counter, part);
        }

        // get the values in the place holders
        // for the example with:
        //   oldFormat: {.*}<b>{.*}</b>{.*}
        //   newFormat: {}<strong>{}</strong>{}
        //   value: abc<b>def</b>ghi
        // it is used the array with the old values between the place holders to get the content in the place holders
        // this result array is that:
        // ------|
        // | abc |
        // ------|
        // | def |
        // |-----|
        // | ghi |
        // |-----|
        ArrayList<String> placeHolders = new ArrayList<String>(oldNumber);
        String tmpValue = value;
        // loop over all rows with the old values between the place holders and take the values between them in the
        // current property value
        for (int placeCounter = 0; placeCounter < (oldBetween.size() - 1); placeCounter++) {
            // get the two next values with the old values between the place holders
            String content = oldBetween.get(placeCounter);
            String nextContent = oldBetween.get(placeCounter + 1);
            // check the position of the first of the next values in the current property value
            int contPos = 0;
            int nextContPos = 0;
            if ((placeCounter == 0) && CmsStringUtil.isEmpty(content)) {
                // the first value in the values between the place holders is empty
                // for example: {.*}<p>...
                contPos = 0;
            } else {
                // the first value in the values between the place holders is NOT empty
                // for example: bla{.*}<p>...
                contPos = tmpValue.indexOf(content);
            }
            // check the position of the second of the next values in the current property value
            if (((placeCounter + 1) == (oldBetween.size() - 1)) && CmsStringUtil.isEmpty(nextContent)) {
                // the last value in the values between the place holders is empty
                // for example: ...<p>{.*}
                nextContPos = tmpValue.length();
            } else {
                // the last value in the values between the place holders is NOT empty
                // for example: ...<p>{.*}bla
                nextContPos = tmpValue.indexOf(nextContent);
            }
            // every value must match the current value
            if ((contPos < 0) || (nextContPos < 0)) {
                return value;
            }
            // get the content of the current place holder
            String placeContent = tmpValue.substring(contPos + content.length(), nextContPos);
            placeHolders.add(placeCounter, placeContent);
            // cut off the currently visited part of the value
            tmpValue = tmpValue.substring(nextContPos);
        }

        // build the new format
        // with following vectors from above:
        // old values between the place holders:
        // ---------
        // | empty | (old.1)
        // ---------
        // | <b>   | (old.2)
        // |--------
        // | </b>  | (old.3)
        // |--------
        // | empty | (old.4)
        // |--------
        //
        // new values between the place holders:
        // ------------|
        // | empty     | (new.1)
        // ------------|
        // | <strong>  | (new.2)
        // |-----------|
        // | </strong> | (new.3)
        // |-----------|
        // | empty     | (new.4)
        // |-----------|
        //
        // content of the place holders:
        // ------|
        // | abc | (place.1)
        // ------|
        // | def | (place.2)
        // |-----|
        // | ghi | (place.3)
        // |-----|
        //
        // the result is calculated in that way:
        // new.1 + place.1 + new.2 + place.2 + new.3 + place.3 + new.4
        String newValue = "";
        // take the values between the place holders and add the content of the place holders
        for (int buildCounter = 0; buildCounter < newNumber; buildCounter++) {
            newValue = newValue + newBetween.get(buildCounter) + placeHolders.get(buildCounter);
        }
        newValue = newValue + newBetween.get(newNumber);
        // return the changed value
        return newValue;
    }

    /**
     * Returns a substring of the source, which is at most length characters long.<p>
     *
     * This is the same as calling {@link #trimToSize(String, int, String)} with the
     * parameters <code>(source, length, " ...")</code>.<p>
     *
     * @param source the string to trim
     * @param length the maximum length of the string to be returned
     *
     * @return a substring of the source, which is at most length characters long
     */
    public static String trimToSize(String source, int length) {

        return trimToSize(source, length, length, " ...");
    }

    /**
     * Returns a substring of the source, which is at most length characters long, cut
     * in the last <code>area</code> chars in the source at a sentence ending char or whitespace.<p>
     *
     * If a char is cut, the given <code>suffix</code> is appended to the result.<p>
     *
     * @param source the string to trim
     * @param length the maximum length of the string to be returned
     * @param area the area at the end of the string in which to find a sentence ender or whitespace
     * @param suffix the suffix to append in case the String was trimmed
     *
     * @return a substring of the source, which is at most length characters long
     */
    public static String trimToSize(String source, int length, int area, String suffix) {

        if ((source == null) || (source.length() <= length)) {
            // no operation is required
            return source;
        }
        if (CmsStringUtil.isEmpty(suffix)) {
            // we need an empty suffix
            suffix = "";
        }
        // must remove the length from the after sequence chars since these are always added in the end
        int modLength = length - suffix.length();
        if (modLength <= 0) {
            // we are to short, return beginning of the suffix
            return suffix.substring(0, length);
        }
        int modArea = area + suffix.length();
        if ((modArea > modLength) || (modArea < 0)) {
            // area must not be longer then max length
            modArea = modLength;
        }

        // first reduce the String to the maximum allowed length
        String findPointSource = source.substring(modLength - modArea, modLength);

        String result;
        // try to find an "sentence ending" char in the text
        int pos = lastIndexOf(findPointSource, SENTENCE_ENDING_CHARS);
        if (pos >= 0) {
            // found a sentence ender in the lookup area, keep the sentence ender
            result = source.substring(0, (modLength - modArea) + pos + 1) + suffix;
        } else {
            // no sentence ender was found, try to find a whitespace
            pos = lastWhitespaceIn(findPointSource);
            if (pos >= 0) {
                // found a whitespace, don't keep the whitespace
                result = source.substring(0, (modLength - modArea) + pos) + suffix;
            } else {
                // not even a whitespace was found, just cut away what's to long
                result = source.substring(0, modLength) + suffix;
            }
        }

        return result;
    }

    /**
     * Returns a substring of the source, which is at most length characters long.<p>
     *
     * If a char is cut, the given <code>suffix</code> is appended to the result.<p>
     *
     * This is almost the same as calling {@link #trimToSize(String, int, int, String)} with the
     * parameters <code>(source, length, length*, suffix)</code>. If <code>length</code>
     * if larger then 100, then <code>length* = length / 2</code>,
     * otherwise <code>length* = length</code>.<p>
     *
     * @param source the string to trim
     * @param length the maximum length of the string to be returned
     * @param suffix the suffix to append in case the String was trimmed
     *
     * @return a substring of the source, which is at most length characters long
     */
    public static String trimToSize(String source, int length, String suffix) {

        int area = (length > 100) ? length / 2 : length;
        return trimToSize(source, length, area, suffix);
    }

    /**
     * Validates a value against a regular expression.<p>
     *
     * @param value the value to test
     * @param regex the regular expression
     * @param allowEmpty if an empty value is allowed
     *
     * @return <code>true</code> if the value satisfies the validation
     */
    public static boolean validateRegex(String value, String regex, boolean allowEmpty) {

        if (CmsStringUtil.isEmptyOrWhitespaceOnly(value)) {
            return allowEmpty;
        }
        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(value);
        return matcher.matches();
    }

}