http://git-wip-us.apache.org/repos/asf/incubator-freemarker/blob/3fd56062/freemarker-core/src/main/java/org/apache/freemarker/core/util/_StringUtil.java
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a/freemarker-core/src/main/java/org/apache/freemarker/core/util/_StringUtil.java
 
b/freemarker-core/src/main/java/org/apache/freemarker/core/util/_StringUtil.java
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+/*
+ * 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 org.apache.freemarker.core.util;
+
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.io.Writer;
+import java.nio.charset.Charset;
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
+import java.util.StringTokenizer;
+import java.util.regex.Pattern;
+
+import org.apache.freemarker.core.Environment;
+import org.apache.freemarker.core.ParsingConfiguration;
+import org.apache.freemarker.core.Template;
+import org.apache.freemarker.core.Version;
+
+/** Don't use this; used internally by FreeMarker, might changes without 
notice. */
+public class _StringUtil {
+
+    private static final char[] LT = new char[] { '&', 'l', 't', ';' };
+    private static final char[] GT = new char[] { '&', 'g', 't', ';' };
+    private static final char[] AMP = new char[] { '&', 'a', 'm', 'p', ';' };
+    private static final char[] QUOT = new char[] { '&', 'q', 'u', 'o', 't', 
';' };
+    private static final char[] HTML_APOS = new char[] { '&', '#', '3', '9', 
';' };
+    private static final char[] XML_APOS = new char[] { '&', 'a', 'p', 'o', 
's', ';' };
+
+    /**
+     *  XML Encoding.
+     *  Replaces all '>' '<' '&', "'" and '"' with entity reference
+     */
+    public static String XMLEnc(String s) {
+        return XMLOrHTMLEnc(s, true, true, XML_APOS);
+    }
+
+    /**
+     * Like {@link #XMLEnc(String)}, but writes the result into a {@link 
Writer}.
+     * 
+     * @since 2.3.24
+     */
+    public static void XMLEnc(String s, Writer out) throws IOException {
+        XMLOrHTMLEnc(s, XML_APOS, out);
+    }
+    
+    /**
+     *  XHTML Encoding.
+     *  Replaces all '>' '<' '&', "'" and '"' with entity reference
+     *  suitable for XHTML decoding in common user agents (including legacy
+     *  user agents, which do not decode "'" to "'", so "'" 
is used
+     *  instead [see http://www.w3.org/TR/xhtml1/#C_16])
+     */
+    public static String XHTMLEnc(String s) {
+        return XMLOrHTMLEnc(s, true, true, HTML_APOS);
+    }
+
+    /**
+     * Like {@link #XHTMLEnc(String)}, but writes the result into a {@link 
Writer}.
+     * 
+     * @since 2.3.24
+     */
+    public static void XHTMLEnc(String s, Writer out) throws IOException {
+        XMLOrHTMLEnc(s, HTML_APOS, out);
+    }
+    
+    private static String XMLOrHTMLEnc(String s, boolean escGT, boolean 
escQuot, char[] apos) {
+        final int ln = s.length();
+        
+        // First we find out if we need to escape, and if so, what the length 
of the output will be:
+        int firstEscIdx = -1;
+        int lastEscIdx = 0;
+        int plusOutLn = 0;
+        for (int i = 0; i < ln; i++) {
+            escape: do {
+                final char c = s.charAt(i);
+                switch (c) {
+                case '<':
+                    plusOutLn += LT.length - 1;
+                    break;
+                case '>':
+                    if (!(escGT || maybeCDataEndGT(s, i))) {
+                        break escape;
+                    }
+                    plusOutLn += GT.length - 1;
+                    break;
+                case '&':
+                    plusOutLn += AMP.length - 1;
+                    break;
+                case '"':
+                    if (!escQuot) {
+                        break escape;
+                    }
+                    plusOutLn += QUOT.length - 1;
+                    break;
+                case '\'': // apos
+                    if (apos == null) {
+                        break escape;
+                    }
+                    plusOutLn += apos.length - 1;
+                    break;
+                default:
+                    break escape;
+                }
+                
+                if (firstEscIdx == -1) {
+                    firstEscIdx = i;
+                }
+                lastEscIdx = i;
+            } while (false);
+        }
+        
+        if (firstEscIdx == -1) {
+            return s; // Nothing to escape
+        } else {
+            final char[] esced = new char[ln + plusOutLn];
+            if (firstEscIdx != 0) {
+                s.getChars(0, firstEscIdx, esced, 0);
+            }
+            int dst = firstEscIdx;
+            scan: for (int i = firstEscIdx; i <= lastEscIdx; i++) {
+                final char c = s.charAt(i);
+                switch (c) {
+                case '<':
+                    dst = shortArrayCopy(LT, esced, dst);
+                    continue scan;
+                case '>':
+                    if (!(escGT || maybeCDataEndGT(s, i))) {
+                        break;
+                    }
+                    dst = shortArrayCopy(GT, esced, dst);
+                    continue scan;
+                case '&':
+                    dst = shortArrayCopy(AMP, esced, dst);
+                    continue scan;
+                case '"':
+                    if (!escQuot) {
+                        break;
+                    }
+                    dst = shortArrayCopy(QUOT, esced, dst);
+                    continue scan;
+                case '\'': // apos
+                    if (apos == null) {
+                        break;
+                    }
+                    dst = shortArrayCopy(apos, esced, dst);
+                    continue scan;
+                }
+                esced[dst++] = c;
+            }
+            if (lastEscIdx != ln - 1) {
+                s.getChars(lastEscIdx + 1, ln, esced, dst);
+            }
+            
+            return String.valueOf(esced);
+        }
+    }
+    
+    private static boolean maybeCDataEndGT(String s, int i) {
+        if (i == 0) return true;
+        if (s.charAt(i - 1) != ']') return false;
+        return i == 1 || s.charAt(i - 2) == ']';
+    }
+
+    private static void XMLOrHTMLEnc(String s, char[] apos, Writer out) throws 
IOException {
+        int writtenEnd = 0;  // exclusive end
+        int ln = s.length();
+        for (int i = 0; i < ln; i++) {
+            char c = s.charAt(i);
+            if (c == '<' || c == '>' || c == '&' || c == '"' || c == '\'') {
+                int flushLn = i - writtenEnd;
+                if (flushLn != 0) {
+                    out.write(s, writtenEnd, flushLn);
+                }
+                writtenEnd = i + 1;
+                
+                switch (c) {
+                case '<': out.write(LT); break;
+                case '>': out.write(GT); break;
+                case '&': out.write(AMP); break;
+                case '"': out.write(QUOT); break;
+                default: out.write(apos); break;
+                }
+            }
+        }
+        if (writtenEnd < ln) {
+            out.write(s, writtenEnd, ln - writtenEnd);
+        }
+    }
+    
+    /**
+     * For efficiently copying very short char arrays.
+     */
+    private static int shortArrayCopy(char[] src, char[] dst, int dstOffset) {
+        for (char aSrc : src) {
+            dst[dstOffset++] = aSrc;
+        }
+        return dstOffset;
+    }
+    
+    /**
+     *  XML encoding without replacing apostrophes.
+     *  @see #XMLEnc(String)
+     */
+    public static String XMLEncNA(String s) {
+        return XMLOrHTMLEnc(s, true, true, null);
+    }
+
+    /**
+     *  XML encoding for attribute values quoted with <tt>"</tt> (not with 
<tt>'</tt>!).
+     *  Also can be used for HTML attributes that are quoted with <tt>"</tt>.
+     *  @see #XMLEnc(String)
+     */
+    public static String XMLEncQAttr(String s) {
+        return XMLOrHTMLEnc(s, false, true, null);
+    }
+
+    /**
+     *  XML encoding without replacing apostrophes and quotation marks and
+     *  greater-thans (except in {@code ]]>}).
+     *  @see #XMLEnc(String)
+     */
+    public static String XMLEncNQG(String s) {
+        return XMLOrHTMLEnc(s, false, false, null);
+    }
+    
+    /**
+     *  Rich Text Format encoding (does not replace line breaks).
+     *  Escapes all '\' '{' '}'.
+     */
+    public static String RTFEnc(String s) {
+        int ln = s.length();
+        
+        // First we find out if we need to escape, and if so, what the length 
of the output will be:
+        int firstEscIdx = -1;
+        int lastEscIdx = 0;
+        int plusOutLn = 0;
+        for (int i = 0; i < ln; i++) {
+            char c = s.charAt(i);
+            if (c == '{' || c == '}' || c == '\\') {
+                if (firstEscIdx == -1) {
+                    firstEscIdx = i;
+                }
+                lastEscIdx = i;
+                plusOutLn++;
+            }
+        }
+        
+        if (firstEscIdx == -1) {
+            return s; // Nothing to escape
+        } else {
+            char[] esced = new char[ln + plusOutLn];
+            if (firstEscIdx != 0) {
+                s.getChars(0, firstEscIdx, esced, 0);
+            }
+            int dst = firstEscIdx;
+            for (int i = firstEscIdx; i <= lastEscIdx; i++) {
+                char c = s.charAt(i);
+                if (c == '{' || c == '}' || c == '\\') {
+                    esced[dst++] = '\\';
+                }
+                esced[dst++] = c;
+            }
+            if (lastEscIdx != ln - 1) {
+                s.getChars(lastEscIdx + 1, ln, esced, dst);
+            }
+            
+            return String.valueOf(esced);
+        }
+    }
+    
+    /**
+     * Like {@link #RTFEnc(String)}, but writes the result into a {@link 
Writer}.
+     * 
+     * @since 2.3.24
+     */
+    public static void RTFEnc(String s, Writer out) throws IOException {
+        int writtenEnd = 0;  // exclusive end
+        int ln = s.length();
+        for (int i = 0; i < ln; i++) {
+            char c = s.charAt(i);
+            if (c == '{' || c == '}' || c == '\\') {
+                int flushLn = i - writtenEnd;
+                if (flushLn != 0) {
+                    out.write(s, writtenEnd, flushLn);
+                }
+                out.write('\\');
+                writtenEnd = i; // Not i + 1, so c will be written out later
+            }
+        }
+        if (writtenEnd < ln) {
+            out.write(s, writtenEnd, ln - writtenEnd);
+        }
+    }
+    
+
+    /**
+     * URL encoding (like%20this) for query parameter values, path 
<em>segments</em>, fragments; this encodes all
+     * characters that are reserved anywhere.
+     */
+    public static String URLEnc(String s, Charset charset) throws 
UnsupportedEncodingException {
+        return URLEnc(s, charset, false);
+    }
+    
+    /**
+     * Like {@link #URLEnc(String, Charset)} but doesn't escape the slash 
character ({@code /}).
+     * This can be used to encode a path only if you know that no folder or 
file name will contain {@code /}
+     * character (not in the path, but in the name itself), which usually 
stands, as the commonly used OS-es don't
+     * allow that.
+     * 
+     * @since 2.3.21
+     */
+    public static String URLPathEnc(String s, Charset charset) throws 
UnsupportedEncodingException {
+        return URLEnc(s, charset, true);
+    }
+    
+    private static String URLEnc(String s, Charset charset, boolean keepSlash)
+            throws UnsupportedEncodingException {
+        int ln = s.length();
+        int i;
+        for (i = 0; i < ln; i++) {
+            char c = s.charAt(i);
+            if (!safeInURL(c, keepSlash)) {
+                break;
+            }
+        }
+        if (i == ln) {
+            // Nothing to escape
+            return s;
+        }
+
+        StringBuilder b = new StringBuilder(ln + ln / 3 + 2);
+        b.append(s.substring(0, i));
+
+        int encStart = i;
+        for (i++; i < ln; i++) {
+            char c = s.charAt(i);
+            if (safeInURL(c, keepSlash)) {
+                if (encStart != -1) {
+                    byte[] o = s.substring(encStart, i).getBytes(charset);
+                    for (byte bc : o) {
+                        b.append('%');
+                        int c1 = bc & 0x0F;
+                        int c2 = (bc >> 4) & 0x0F;
+                        b.append((char) (c2 < 10 ? c2 + '0' : c2 - 10 + 'A'));
+                        b.append((char) (c1 < 10 ? c1 + '0' : c1 - 10 + 'A'));
+                    }
+                    encStart = -1;
+                }
+                b.append(c);
+            } else {
+                if (encStart == -1) {
+                    encStart = i;
+                }
+            }
+        }
+        if (encStart != -1) {
+            byte[] o = s.substring(encStart, i).getBytes(charset);
+            for (byte bc : o) {
+                b.append('%');
+                int c1 = bc & 0x0F;
+                int c2 = (bc >> 4) & 0x0F;
+                b.append((char) (c2 < 10 ? c2 + '0' : c2 - 10 + 'A'));
+                b.append((char) (c1 < 10 ? c1 + '0' : c1 - 10 + 'A'));
+            }
+        }
+        
+        return b.toString();
+    }
+
+    private static boolean safeInURL(char c, boolean keepSlash) {
+        return c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z'
+                || c >= '0' && c <= '9'
+                || c == '_' || c == '-' || c == '.' || c == '!' || c == '~'
+                || c >= '\'' && c <= '*'
+                || keepSlash && c == '/';
+    }
+
+    public static Locale deduceLocale(String input) {
+       if (input == null) return null;
+       Locale locale = Locale.getDefault();
+       if (input.length() > 0 && input.charAt(0) == '"') input = 
input.substring(1, input.length() - 1);
+       StringTokenizer st = new StringTokenizer(input, ",_ ");
+       String lang = "", country = "";
+       if (st.hasMoreTokens()) {
+          lang = st.nextToken();
+       }
+       if (st.hasMoreTokens()) {
+          country = st.nextToken();
+       }
+       if (!st.hasMoreTokens()) {
+          locale = new Locale(lang, country);
+       } else {
+          locale = new Locale(lang, country, st.nextToken());
+       }
+       return locale;
+    }
+
+    public static String capitalize(String s) {
+        StringTokenizer st = new StringTokenizer(s, " \t\r\n", true);
+        StringBuilder buf = new StringBuilder(s.length());
+        while (st.hasMoreTokens()) {
+            String tok = st.nextToken();
+            buf.append(tok.substring(0, 1).toUpperCase());
+            buf.append(tok.substring(1).toLowerCase());
+        }
+        return buf.toString();
+    }
+
+    public static boolean getYesNo(String s) {
+        if (s.startsWith("\"")) {
+            s = s.substring(1, s.length() - 1);
+
+        }
+        if (s.equalsIgnoreCase("n")
+                || s.equalsIgnoreCase("no")
+                || s.equalsIgnoreCase("f")
+                || s.equalsIgnoreCase("false")) {
+            return false;
+        } else if (s.equalsIgnoreCase("y")
+                || s.equalsIgnoreCase("yes")
+                || s.equalsIgnoreCase("t")
+                || s.equalsIgnoreCase("true")) {
+            return true;
+        }
+        throw new IllegalArgumentException("Illegal boolean value: " + s);
+    }
+
+    /**
+     * Splits a string at the specified character.
+     */
+    public static String[] split(String s, char c) {
+        int i, b, e;
+        int cnt;
+        String res[];
+        int ln = s.length();
+
+        i = 0;
+        cnt = 1;
+        while ((i = s.indexOf(c, i)) != -1) {
+            cnt++;
+            i++;
+        }
+        res = new String[cnt];
+
+        i = 0;
+        b = 0;
+        while (b <= ln) {
+            e = s.indexOf(c, b);
+            if (e == -1) e = ln;
+            res[i++] = s.substring(b, e);
+            b = e + 1;
+        }
+        return res;
+    }
+
+    /**
+     * Splits a string at the specified string.
+     */
+    public static String[] split(String s, String sep, boolean 
caseInsensitive) {
+        String splitString = caseInsensitive ? sep.toLowerCase() : sep;
+        String input = caseInsensitive ? s.toLowerCase() : s;
+        int i, b, e;
+        int cnt;
+        String res[];
+        int ln = s.length();
+        int sln = sep.length();
+
+        if (sln == 0) throw new IllegalArgumentException(
+                "The separator string has 0 length");
+
+        i = 0;
+        cnt = 1;
+        while ((i = input.indexOf(splitString, i)) != -1) {
+            cnt++;
+            i += sln;
+        }
+        res = new String[cnt];
+
+        i = 0;
+        b = 0;
+        while (b <= ln) {
+            e = input.indexOf(splitString, b);
+            if (e == -1) e = ln;
+            res[i++] = s.substring(b, e);
+            b = e + sln;
+        }
+        return res;
+    }
+
+    /**
+     * Same as {@link #replace(String, String, String, boolean, boolean)} with 
two {@code false} parameters. 
+     * @since 2.3.20
+     */
+    public static String replace(String text, String oldSub, String newSub) {
+        return replace(text, oldSub, newSub, false, false);
+    }
+    
+    /**
+     * Replaces all occurrences of a sub-string in a string.
+     * @param text The string where it will replace <code>oldSub</code> with
+     *     <code>newSub</code>.
+     * @return String The string after the replacements.
+     */
+    public static String replace(String text, 
+                                  String oldSub,
+                                  String newSub,
+                                  boolean caseInsensitive,
+                                  boolean firstOnly) {
+        StringBuilder buf;
+        int tln;
+        int oln = oldSub.length();
+        
+        if (oln == 0) {
+            int nln = newSub.length();
+            if (nln == 0) {
+                return text;
+            } else {
+                if (firstOnly) {
+                    return newSub + text;
+                } else {
+                    tln = text.length();
+                    buf = new StringBuilder(tln + (tln + 1) * nln);
+                    buf.append(newSub);
+                    for (int i = 0; i < tln; i++) {
+                        buf.append(text.charAt(i));
+                        buf.append(newSub);
+                    }
+                    return buf.toString();
+                }
+            }
+        } else {
+            oldSub = caseInsensitive ? oldSub.toLowerCase() : oldSub;
+            String input = caseInsensitive ? text.toLowerCase() : text;
+            int e = input.indexOf(oldSub);
+            if (e == -1) {
+                return text;
+            }
+            int b = 0;
+            tln = text.length();
+            buf = new StringBuilder(
+                    tln + Math.max(newSub.length() - oln, 0) * 3);
+            do {
+                buf.append(text.substring(b, e));
+                buf.append(newSub);
+                b = e + oln;
+                e = input.indexOf(oldSub, b);
+            } while (e != -1 && !firstOnly);
+            buf.append(text.substring(b));
+            return buf.toString();
+        }
+    }
+
+    /**
+     * Removes a line-break from the end of the string (if there's any).
+     */
+    public static String chomp(String s) {
+        if (s.endsWith("\r\n")) return s.substring(0, s.length() - 2);
+        if (s.endsWith("\r") || s.endsWith("\n"))
+                return s.substring(0, s.length() - 1);
+        return s;
+    }
+
+    /**
+     * Converts a 0-length string to null, leaves the string as is otherwise.
+     * @param s maybe {@code null}.
+     */
+    public static String emptyToNull(String s) {
+       if (s == null) return null;
+       return s.length() == 0 ? null : s;
+    }
+    
+    /**
+     * Converts the parameter with <code>toString</code> (if it's not 
<code>null</code>) and passes it to
+     * {@link #jQuote(String)}.
+     */
+    public static String jQuote(Object obj) {
+        return jQuote(obj != null ? obj.toString() : null);
+    }
+    
+    /**
+     * Quotes string as Java Language string literal.
+     * Returns string <code>"null"</code> if <code>s</code>
+     * is <code>null</code>.
+     */
+    public static String jQuote(String s) {
+        if (s == null) {
+            return "null";
+        }
+        int ln = s.length();
+        StringBuilder b = new StringBuilder(ln + 4);
+        b.append('"');
+        for (int i = 0; i < ln; i++) {
+            char c = s.charAt(i);
+            if (c == '"') {
+                b.append("\\\"");
+            } else if (c == '\\') {
+                b.append("\\\\");
+            } else if (c < 0x20) {
+                if (c == '\n') {
+                    b.append("\\n");
+                } else if (c == '\r') {
+                    b.append("\\r");
+                } else if (c == '\f') {
+                    b.append("\\f");
+                } else if (c == '\b') {
+                    b.append("\\b");
+                } else if (c == '\t') {
+                    b.append("\\t");
+                } else {
+                    b.append("\\u00");
+                    int x = c / 0x10;
+                    b.append(toHexDigit(x));
+                    x = c & 0xF;
+                    b.append(toHexDigit(x));
+                }
+            } else {
+                b.append(c);
+            }
+        } // for each characters
+        b.append('"');
+        return b.toString();
+    }
+
+    /**
+     * Converts the parameter with <code>toString</code> (if not
+     * <code>null</code>)and passes it to {@link #jQuoteNoXSS(String)}. 
+     */
+    public static String jQuoteNoXSS(Object obj) {
+        return jQuoteNoXSS(obj != null ? obj.toString() : null);
+    }
+    
+    /**
+     * Same as {@link #jQuote(String)} but also escapes <code>'&lt;'</code>
+     * as <code>\</code><code>u003C</code>. This is used for log messages to 
prevent XSS
+     * on poorly written Web-based log viewers. 
+     */
+    public static String jQuoteNoXSS(String s) {
+        if (s == null) {
+            return "null";
+        }
+        int ln = s.length();
+        StringBuilder b = new StringBuilder(ln + 4);
+        b.append('"');
+        for (int i = 0; i < ln; i++) {
+            char c = s.charAt(i);
+            if (c == '"') {
+                b.append("\\\"");
+            } else if (c == '\\') {
+                b.append("\\\\");
+            } else if (c == '<') {
+                b.append("\\u003C");
+            } else if (c < 0x20) {
+                if (c == '\n') {
+                    b.append("\\n");
+                } else if (c == '\r') {
+                    b.append("\\r");
+                } else if (c == '\f') {
+                    b.append("\\f");
+                } else if (c == '\b') {
+                    b.append("\\b");
+                } else if (c == '\t') {
+                    b.append("\\t");
+                } else {
+                    b.append("\\u00");
+                    int x = c / 0x10;
+                    b.append(toHexDigit(x));
+                    x = c & 0xF;
+                    b.append(toHexDigit(x));
+                }
+            } else {
+                b.append(c);
+            }
+        } // for each characters
+        b.append('"');
+        return b.toString();
+    }
+
+    /**
+     * Escapes the <code>String</code> with the escaping rules of Java language
+     * string literals, so it's safe to insert the value into a string literal.
+     * The resulting string will not be quoted.
+     * 
+     * <p>All characters under UCS code point 0x20 will be escaped.
+     * Where they have no dedicated escape sequence in Java, they will
+     * be replaced with hexadecimal escape (<tt>\</tt><tt>u<i>XXXX</i></tt>). 
+     * 
+     * @see #jQuote(String)
+     */ 
+    public static String javaStringEnc(String s) {
+        int ln = s.length();
+        for (int i = 0; i < ln; i++) {
+            char c = s.charAt(i);
+            if (c == '"' || c == '\\' || c < 0x20) {
+                StringBuilder b = new StringBuilder(ln + 4);
+                b.append(s.substring(0, i));
+                while (true) {
+                    if (c == '"') {
+                        b.append("\\\"");
+                    } else if (c == '\\') {
+                        b.append("\\\\");
+                    } else if (c < 0x20) {
+                        if (c == '\n') {
+                            b.append("\\n");
+                        } else if (c == '\r') {
+                            b.append("\\r");
+                        } else if (c == '\f') {
+                            b.append("\\f");
+                        } else if (c == '\b') {
+                            b.append("\\b");
+                        } else if (c == '\t') {
+                            b.append("\\t");
+                        } else {
+                            b.append("\\u00");
+                            int x = c / 0x10;
+                            b.append((char)
+                                    (x < 0xA ? x + '0' : x - 0xA + 'a'));
+                            x = c & 0xF;
+                            b.append((char)
+                                    (x < 0xA ? x + '0' : x - 0xA + 'a'));
+                        }
+                    } else {
+                        b.append(c);
+                    }
+                    i++;
+                    if (i >= ln) {
+                        return b.toString();
+                    }
+                    c = s.charAt(i);
+                }
+            } // if has to be escaped
+        } // for each characters
+        return s;
+    }
+    
+    /**
+     * Escapes a {@link String} to be safely insertable into a JavaScript 
string literal; for more see
+     * {@link #jsStringEnc(String, boolean) jsStringEnc(s, false)}.
+     */
+    public static String javaScriptStringEnc(String s) {
+        return jsStringEnc(s, false);
+    }
+
+    /**
+     * Escapes a {@link String} to be safely insertable into a JSON string 
literal; for more see
+     * {@link #jsStringEnc(String, boolean) jsStringEnc(s, true)}.
+     */
+    public static String jsonStringEnc(String s) {
+        return jsStringEnc(s, true);
+    }
+
+    private static final int NO_ESC = 0;
+    private static final int ESC_HEXA = 1;
+    private static final int ESC_BACKSLASH = 3;
+    
+    /**
+     * Escapes a {@link String} to be safely insertable into a JavaScript or a 
JSON string literal.
+     * The resulting string will <em>not</em> be quoted; the caller must 
ensure that they are there in the final
+     * output. Note that for JSON, the quotation marks must be {@code "}, not 
{@code '}, because JSON doesn't escape
+     * {@code '}.
+     * 
+     * <p>The escaping rules guarantee that if the inside of the 
JavaScript/JSON string literal is from one or more
+     * touching pieces that were escaped with this, no character sequence can 
occur that closes the
+     * JavaScript/JSON string literal, or has a meaning in HTML/XML that 
causes the HTML script section to be closed.
+     * (If, however, the escaped section is preceded by or followed by strings 
from other sources, this can't be
+     * guaranteed in some rare cases. Like <tt>x = "&lt;/${a?js_string}"</tt> 
might closes the "script"
+     * element if {@code a} is {@code "script>"}.)
+     * 
+     * The escaped characters are:
+     * 
+     * <table style="width: auto; border-collapse: collapse" border="1" 
summary="Characters escaped by jsStringEnc">
+     * <tr>
+     *   <th>Input
+     *   <th>Output
+     * <tr>
+     *   <td><tt>"</tt>
+     *   <td><tt>\"</tt>
+     * <tr>
+     *   <td><tt>'</tt> if not in JSON-mode
+     *   <td><tt>\'</tt>
+     * <tr>
+     *   <td><tt>\</tt>
+     *   <td><tt>\\</tt>
+     * <tr>
+     *   <td><tt>/</tt> if the method can't know that it won't be directly 
after <tt>&lt;</tt>
+     *   <td><tt>\/</tt>
+     * <tr>
+     *   <td><tt>&gt;</tt> if the method can't know that it won't be directly 
after <tt>]]</tt> or <tt>--</tt>
+     *   <td>JavaScript: <tt>\&gt;</tt>; JSON: <tt>\</tt><tt>u003E</tt>
+     * <tr>
+     *   <td><tt>&lt;</tt> if the method can't know that it won't be directly 
followed by <tt>!</tt> or <tt>?</tt> 
+     *   <td><tt><tt>\</tt>u003C</tt>
+     * <tr>
+     *   <td>
+     *     u0000-u001f (UNICODE control characters - disallowed by JSON)<br>
+     *     u007f-u009f (UNICODE control characters - disallowed by JSON)
+     *   <td><tt>\n</tt>, <tt>\r</tt> and such, or if there's no such 
dedicated escape:
+     *       JavaScript: <tt>\x<i>XX</i></tt>, JSON: 
<tt>\<tt>u</tt><i>XXXX</i></tt>
+     * <tr>
+     *   <td>
+     *     u2028 (Line separator - source code line-break in ECMAScript)<br>
+     *     u2029 (Paragraph separator - source code line-break in 
ECMAScript)<br>
+     *   <td><tt>\<tt>u</tt><i>XXXX</i></tt>
+     * </table>
+     * 
+     * @since 2.3.20
+     */
+    public static String jsStringEnc(String s, boolean json) {
+        _NullArgumentException.check("s", s);
+        
+        int ln = s.length();
+        StringBuilder sb = null;
+        for (int i = 0; i < ln; i++) {
+            final char c = s.charAt(i);
+            final int escapeType;  // 
+            if (!(c > '>' && c < 0x7F && c != '\\') && c != ' ' && !(c >= 0xA0 
&& c < 0x2028)) {  // skip common chars
+                if (c <= 0x1F) {  // control chars range 1
+                    if (c == '\n') {
+                        escapeType = 'n';
+                    } else if (c == '\r') {
+                        escapeType = 'r';
+                    } else if (c == '\f') {
+                        escapeType = 'f';
+                    } else if (c == '\b') {
+                        escapeType = 'b';
+                    } else if (c == '\t') {
+                        escapeType = 't';
+                    } else {
+                        escapeType = ESC_HEXA;
+                    }
+                } else if (c == '"') {
+                    escapeType = ESC_BACKSLASH;
+                } else if (c == '\'') {
+                    escapeType = json ? NO_ESC : ESC_BACKSLASH; 
+                } else if (c == '\\') {
+                    escapeType = ESC_BACKSLASH; 
+                } else if (c == '/' && (i == 0 || s.charAt(i - 1) == '<')) {  
// against closing elements
+                    escapeType = ESC_BACKSLASH; 
+                } else if (c == '>') {  // against "]]> and "-->"
+                    final boolean dangerous;
+                    if (i == 0) {
+                        dangerous = true;
+                    } else {
+                        final char prevC = s.charAt(i - 1);
+                        if (prevC == ']' || prevC == '-') {
+                            if (i == 1) {
+                                dangerous = true;
+                            } else {
+                                final char prevPrevC = s.charAt(i - 2);
+                                dangerous = prevPrevC == prevC;
+                            }
+                        } else {
+                            dangerous = false;
+                        }
+                    }
+                    escapeType = dangerous ? (json ? ESC_HEXA : ESC_BACKSLASH) 
: NO_ESC;
+                } else if (c == '<') {  // against "<!"
+                    final boolean dangerous;
+                    if (i == ln - 1) {
+                        dangerous = true;
+                    } else {
+                        char nextC = s.charAt(i + 1);
+                        dangerous = nextC == '!' || nextC == '?';
+                    }
+                    escapeType = dangerous ? ESC_HEXA : NO_ESC;
+                } else if ((c >= 0x7F && c <= 0x9F)  // control chars range 2
+                            || (c == 0x2028 || c == 0x2029)  // UNICODE line 
terminators
+                            ) {
+                    escapeType = ESC_HEXA;
+                } else {
+                    escapeType = NO_ESC;
+                }
+                
+                if (escapeType != NO_ESC) { // If needs escaping
+                    if (sb == null) {
+                        sb = new StringBuilder(ln + 6);
+                        sb.append(s.substring(0, i));
+                    }
+                    
+                    sb.append('\\');
+                    if (escapeType > 0x20) {
+                        sb.append((char) escapeType);
+                    } else if (escapeType == ESC_HEXA) {
+                        if (!json && c < 0x100) {
+                            sb.append('x');
+                            sb.append(toHexDigit(c >> 4));
+                            sb.append(toHexDigit(c & 0xF));
+                        } else {
+                            sb.append('u');
+                            sb.append(toHexDigit((c >> 12) & 0xF));
+                            sb.append(toHexDigit((c >> 8) & 0xF));
+                            sb.append(toHexDigit((c >> 4) & 0xF));
+                            sb.append(toHexDigit(c & 0xF));
+                        }
+                    } else {  // escapeType == ESC_BACKSLASH
+                        sb.append(c);
+                    }
+                    continue; 
+                }
+                // Falls through when escapeType == NO_ESC 
+            }
+            // Needs no escaping
+                
+            if (sb != null) sb.append(c);
+        } // for each characters
+        
+        return sb == null ? s : sb.toString();
+    }
+
+    private static char toHexDigit(int d) {
+        return (char) (d < 0xA ? d + '0' : d - 0xA + 'A');
+    }
+    
+    /**
+     * Parses a name-value pair list, where the pairs are separated with comma,
+     * and the name and value is separated with colon.
+     * The keys and values can contain only letters, digits and <tt>_</tt>. 
They
+     * can't be quoted. White-space around the keys and values are ignored. The
+     * value can be omitted if <code>defaultValue</code> is not null. When a
+     * value is omitted, then the colon after the key must be omitted as well.
+     * The same key can't be used for multiple times.
+     * 
+     * @param s the string to parse.
+     *     For example: <code>"strong:100, soft:900"</code>.
+     * @param defaultValue the value used when the value is omitted in a
+     *     key-value pair.
+     * 
+     * @return the map that contains the name-value pairs.
+     * 
+     * @throws java.text.ParseException if the string is not a valid name-value
+     *     pair list.
+     */
+    public static Map parseNameValuePairList(String s, String defaultValue)
+    throws java.text.ParseException {
+        Map map = new HashMap();
+        
+        char c = ' ';
+        int ln = s.length();
+        int p = 0;
+        int keyStart;
+        int valueStart;
+        String key;
+        String value;
+        
+        fetchLoop: while (true) {
+            // skip ws
+            while (p < ln) {
+                c = s.charAt(p);
+                if (!Character.isWhitespace(c)) {
+                    break;
+                }
+                p++;
+            }
+            if (p == ln) {
+                break fetchLoop;
+            }
+            keyStart = p;
+
+            // seek key end
+            while (p < ln) {
+                c = s.charAt(p);
+                if (!(Character.isLetterOrDigit(c) || c == '_')) {
+                    break;
+                }
+                p++;
+            }
+            if (keyStart == p) {
+                throw new java.text.ParseException(
+                       "Expecting letter, digit or \"_\" "
+                        + "here, (the first character of the key) but found "
+                        + jQuote(String.valueOf(c))
+                        + " at position " + p + ".",
+                        p);
+            }
+            key = s.substring(keyStart, p);
+
+            // skip ws
+            while (p < ln) {
+                c = s.charAt(p);
+                if (!Character.isWhitespace(c)) {
+                    break;
+                }
+                p++;
+            }
+            if (p == ln) {
+                if (defaultValue == null) {
+                    throw new java.text.ParseException(
+                            "Expecting \":\", but reached "
+                            + "the end of the string "
+                            + " at position " + p + ".",
+                            p);
+                }
+                value = defaultValue;
+            } else if (c != ':') {
+                if (defaultValue == null || c != ',') {
+                    throw new java.text.ParseException(
+                            "Expecting \":\" here, but found "
+                            + jQuote(String.valueOf(c))
+                            + " at position " + p + ".",
+                            p);
+                }
+
+                // skip ","
+                p++;
+                
+                value = defaultValue;
+            } else {
+                // skip ":"
+                p++;
+    
+                // skip ws
+                while (p < ln) {
+                    c = s.charAt(p);
+                    if (!Character.isWhitespace(c)) {
+                        break;
+                    }
+                    p++;
+                }
+                if (p == ln) {
+                    throw new java.text.ParseException(
+                            "Expecting the value of the key "
+                            + "here, but reached the end of the string "
+                            + " at position " + p + ".",
+                            p);
+                }
+                valueStart = p;
+    
+                // seek value end
+                while (p < ln) {
+                    c = s.charAt(p);
+                    if (!(Character.isLetterOrDigit(c) || c == '_')) {
+                        break;
+                    }
+                    p++;
+                }
+                if (valueStart == p) {
+                    throw new java.text.ParseException(
+                            "Expecting letter, digit or \"_\" "
+                            + "here, (the first character of the value) "
+                            + "but found "
+                            + jQuote(String.valueOf(c))
+                            + " at position " + p + ".",
+                            p);
+                }
+                value = s.substring(valueStart, p);
+
+                // skip ws
+                while (p < ln) {
+                    c = s.charAt(p);
+                    if (!Character.isWhitespace(c)) {
+                        break;
+                    }
+                    p++;
+                }
+                
+                // skip ","
+                if (p < ln) {
+                    if (c != ',') {
+                        throw new java.text.ParseException(
+                                "Excpecting \",\" or the end "
+                                + "of the string here, but found "
+                                + jQuote(String.valueOf(c))
+                                + " at position " + p + ".",
+                                p);
+                    } else {
+                        p++;
+                    }
+                }
+            }
+            
+            // store the key-value pair
+            if (map.put(key, value) != null) {
+                throw new java.text.ParseException(
+                        "Dublicated key: "
+                        + jQuote(key), keyStart);
+            }
+        }
+        
+        return map;
+    }
+    
+    /**
+     * @return whether the qname matches the combination of nodeName, nsURI, 
and environment prefix settings.
+     */
+    static public boolean matchesQName(String qname, String nodeName, String 
nsURI, Environment env) {
+        String defaultNS = env.getDefaultNS();
+        if ((defaultNS != null) && defaultNS.equals(nsURI)) {
+            return qname.equals(nodeName)
+                    || qname.equals(Template.DEFAULT_NAMESPACE_PREFIX + ":" + 
nodeName);
+        }
+        if ("".equals(nsURI)) {
+            if (defaultNS != null) {
+                return qname.equals(Template.NO_NS_PREFIX + ":" + nodeName);
+            } else {
+                return qname.equals(nodeName) || 
qname.equals(Template.NO_NS_PREFIX + ":" + nodeName);
+            }
+        }
+        String prefix = env.getPrefixForNamespace(nsURI);
+        if (prefix == null) {
+            return false; // Is this the right thing here???
+        }
+        return qname.equals(prefix + ":" + nodeName);
+    }
+    
+    /**
+     * Pads the string at the left with spaces until it reaches the desired
+     * length. If the string is longer than this length, then it returns the
+     * unchanged string. 
+     * 
+     * @param s the string that will be padded.
+     * @param minLength the length to reach.
+     */
+    public static String leftPad(String s, int minLength) {
+        return leftPad(s, minLength, ' ');
+    }
+    
+    /**
+     * Pads the string at the left with the specified character until it 
reaches
+     * the desired length. If the string is longer than this length, then it
+     * returns the unchanged string.
+     * 
+     * @param s the string that will be padded.
+     * @param minLength the length to reach.
+     * @param filling the filling pattern.
+     */
+    public static String leftPad(String s, int minLength, char filling) {
+        int ln = s.length();
+        if (minLength <= ln) {
+            return s;
+        }
+        
+        StringBuilder res = new StringBuilder(minLength);
+        
+        int dif = minLength - ln;
+        for (int i = 0; i < dif; i++) {
+            res.append(filling);
+        }
+        
+        res.append(s);
+        
+        return res.toString();
+    }
+
+    /**
+     * Pads the string at the left with a filling pattern until it reaches the
+     * desired length. If the string is longer than this length, then it 
returns
+     * the unchanged string. For example: <code>leftPad('ABC', 9, 
'1234')</code>
+     * returns <code>"123412ABC"</code>.
+     * 
+     * @param s the string that will be padded.
+     * @param minLength the length to reach.
+     * @param filling the filling pattern. Must be at least 1 characters long.
+     *     Can't be <code>null</code>.
+     */
+    public static String leftPad(String s, int minLength, String filling) {
+        int ln = s.length();
+        if (minLength <= ln) {
+            return s;
+        }
+        
+        StringBuilder res = new StringBuilder(minLength);
+
+        int dif = minLength - ln;
+        int fln = filling.length();
+        if (fln == 0) {
+            throw new IllegalArgumentException(
+                    "The \"filling\" argument can't be 0 length string.");
+        }
+        int cnt = dif / fln;
+        for (int i = 0; i < cnt; i++) {
+            res.append(filling);
+        }
+        cnt = dif % fln;
+        for (int i = 0; i < cnt; i++) {
+            res.append(filling.charAt(i));
+        }
+        
+        res.append(s);
+        
+        return res.toString();
+    }
+    
+    /**
+     * Pads the string at the right with spaces until it reaches the desired
+     * length. If the string is longer than this length, then it returns the
+     * unchanged string. 
+     * 
+     * @param s the string that will be padded.
+     * @param minLength the length to reach.
+     */
+    public static String rightPad(String s, int minLength) {
+        return rightPad(s, minLength, ' ');
+    }
+    
+    /**
+     * Pads the string at the right with the specified character until it
+     * reaches the desired length. If the string is longer than this length,
+     * then it returns the unchanged string.
+     * 
+     * @param s the string that will be padded.
+     * @param minLength the length to reach.
+     * @param filling the filling pattern.
+     */
+    public static String rightPad(String s, int minLength, char filling) {
+        int ln = s.length();
+        if (minLength <= ln) {
+            return s;
+        }
+        
+        StringBuilder res = new StringBuilder(minLength);
+
+        res.append(s);
+        
+        int dif = minLength - ln;
+        for (int i = 0; i < dif; i++) {
+            res.append(filling);
+        }
+        
+        return res.toString();
+    }
+
+    /**
+     * Pads the string at the right with a filling pattern until it reaches the
+     * desired length. If the string is longer than this length, then it 
returns
+     * the unchanged string. For example: <code>rightPad('ABC', 9, 
'1234')</code>
+     * returns <code>"ABC412341"</code>. Note that the filling pattern is
+     * started as if you overlay <code>"123412341"</code> with the left-aligned
+     * <code>"ABC"</code>, so it starts with <code>"4"</code>.
+     * 
+     * @param s the string that will be padded.
+     * @param minLength the length to reach.
+     * @param filling the filling pattern. Must be at least 1 characters long.
+     *     Can't be <code>null</code>.
+     */
+    public static String rightPad(String s, int minLength, String filling) {
+        int ln = s.length();
+        if (minLength <= ln) {
+            return s;
+        }
+        
+        StringBuilder res = new StringBuilder(minLength);
+
+        res.append(s);
+
+        int dif = minLength - ln;
+        int fln = filling.length();
+        if (fln == 0) {
+            throw new IllegalArgumentException(
+                    "The \"filling\" argument can't be 0 length string.");
+        }
+        int start = ln % fln;
+        int end = fln - start <= dif
+                ? fln
+                : start + dif;
+        for (int i = start; i < end; i++) {
+            res.append(filling.charAt(i));
+        }
+        dif -= end - start;
+        int cnt = dif / fln;
+        for (int i = 0; i < cnt; i++) {
+            res.append(filling);
+        }
+        cnt = dif % fln;
+        for (int i = 0; i < cnt; i++) {
+            res.append(filling.charAt(i));
+        }
+        
+        return res.toString();
+    }
+    
+    /**
+     * Converts a version number string to an integer for easy comparison.
+     * The version number must start with numbers separated with
+     * dots. There can be any number of such dot-separated numbers, but only
+     * the first three will be considered. After the numbers arbitrary text can
+     * follow, and will be ignored.
+     * 
+     * The string will be trimmed before interpretation.
+     * 
+     * @return major * 1000000 + minor * 1000 + micro
+     */
+    public static int versionStringToInt(String version) {
+        return new Version(version).intValue();
+    }
+
+    /**
+     * Tries to run {@code toString()}, but if that fails, returns a
+     * {@code "[com.example.SomeClass.toString() failed: " + e + "]"} instead. 
Also, it returns {@code null} for
+     * {@code null} parameter.
+     * 
+     * @since 2.3.20
+     */
+    public static String tryToString(Object object) {
+        if (object == null) return null;
+        
+        try {
+            return object.toString();
+        } catch (Throwable e) {
+            return failedToStringSubstitute(object, e);
+        }
+    }
+
+    private static String failedToStringSubstitute(Object object, Throwable e) 
{
+        String eStr;
+        try {
+            eStr = e.toString();
+        } catch (Throwable e2) {
+            eStr = _ClassUtil.getShortClassNameOfObject(e);
+        }
+        return "[" + _ClassUtil.getShortClassNameOfObject(object) + 
".toString() failed: " + eStr + "]";
+    }
+    
+    /**
+     * Converts {@code 1}, {@code 2}, {@code 3} and so forth to {@code "A"}, 
{@code "B"}, {@code "C"} and so fort. When
+     * reaching {@code "Z"}, it continues like {@code "AA"}, {@code "AB"}, 
etc. The lowest supported number is 1, but
+     * there's no upper limit.
+     * 
+     * @throws IllegalArgumentException
+     *             If the argument is 0 or less.
+     * 
+     * @since 2.3.22
+     */
+    public static String toUpperABC(int n) {
+        return toABC(n, 'A');
+    }
+
+    /**
+     * Same as {@link #toUpperABC(int)}, but produces lower case result, like 
{@code "ab"}.
+     * 
+     * @since 2.3.22
+     */
+    public static String toLowerABC(int n) {
+        return toABC(n, 'a');
+    }
+
+    /**
+     * @param oneDigit
+     *            The character that stands for the value 1.
+     */
+    private static String toABC(final int n, char oneDigit) {
+        if (n < 1) {
+            throw new IllegalArgumentException("Can't convert 0 or negative "
+                    + "numbers to latin-number: " + n);
+        }
+        
+        // First find out how many "digits" will we need. We start from A, then
+        // try AA, then AAA, etc. (Note that the smallest digit is "A", which 
is
+        // 1, not 0. Hence this isn't like a usual 26-based number-system):
+        int reached = 1;
+        int weight = 1;
+        while (true) {
+            int nextWeight = weight * 26;
+            int nextReached = reached + nextWeight;
+            if (nextReached <= n) {
+                // So we will have one more digit
+                weight = nextWeight;
+                reached = nextReached;
+            } else {
+                // No more digits
+                break;
+            }
+        }
+        
+        // Increase the digits of the place values until we get as close
+        // to n as possible (but don't step over it).
+        StringBuilder sb = new StringBuilder();
+        while (weight != 0) {
+            // digitIncrease: how many we increase the digit which is already 1
+            final int digitIncrease = (n - reached) / weight;
+            sb.append((char) (oneDigit + digitIncrease));
+            reached += digitIncrease * weight;
+            
+            weight /= 26;
+        }
+        
+        return sb.toString();
+    }
+
+    /**
+     * Behaves exactly like {@link String#trim()}, but works on arrays. If the 
resulting array would have the same
+     * content after trimming, it returns the original array instance. 
Otherwise it returns a new array instance (or
+     * {@link _CollectionUtil#EMPTY_CHAR_ARRAY}).
+     * 
+     * @since 2.3.22
+     */
+    public static char[] trim(final char[] cs) {
+        if (cs.length == 0) {
+            return cs;
+        }
+        
+        int start = 0;
+        int end = cs.length;
+        while (start < end && cs[start] <= ' ') {
+            start++;
+        }
+        while (start < end && cs[end - 1] <= ' ') {
+            end--;
+        }
+        
+        if (start == 0 && end == cs.length) {
+            return cs;
+        }
+        if (start == end) {
+            return _CollectionUtil.EMPTY_CHAR_ARRAY;
+        }
+        
+        char[] newCs = new char[end - start];
+        System.arraycopy(cs, start, newCs, 0, end - start);
+        return newCs;
+    }
+
+    /**
+     * Tells if {@link String#trim()} will return a 0-length string for the 
{@link String} equivalent of the argument.
+     * 
+     * @since 2.3.22
+     */
+    public static boolean isTrimmableToEmpty(char[] text) {
+        return isTrimmableToEmpty(text, 0, text.length);
+    }
+
+    /**
+     * Like {@link #isTrimmableToEmpty(char[])}, but acts on a sub-array that 
starts at {@code start} (inclusive index).
+     * 
+     * @since 2.3.23
+     */
+    public static boolean isTrimmableToEmpty(char[] text, int start) {
+        return isTrimmableToEmpty(text, start, text.length);
+    }
+    
+    /**
+     * Like {@link #isTrimmableToEmpty(char[])}, but acts on a sub-array that 
starts at {@code start} (inclusive index)
+     * and ends at {@code end} (exclusive index).
+     * 
+     * @since 2.3.23
+     */
+    public static boolean isTrimmableToEmpty(char[] text, int start, int end) {
+        for (int i = start; i < end; i++) {
+            // We follow Java's String.trim() here, which simply states that c 
<= ' ' is whitespace.
+            if (text[i] > ' ') {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Same as {@link #globToRegularExpression(String, boolean)} with {@code 
caseInsensitive} argument {@code false}.
+     * 
+     * @since 2.3.24
+     */
+    public static Pattern globToRegularExpression(String glob) {
+        return globToRegularExpression(glob, false);
+    }
+    
+    /**
+     * Creates a regular expression from a glob. The glob must use {@code /} 
for as file separator, not {@code \}
+     * (backslash), and is always case sensitive.
+     *
+     * <p>This glob implementation recognizes these special characters:
+     * <ul>
+     *   <li>{@code ?}: Wildcard that matches exactly one character, other 
than {@code /} 
+     *   <li>{@code *}: Wildcard that matches zero, one or multiple 
characters, other than {@code /}
+     *   <li>{@code **}: Wildcard that matches zero, one or multiple 
directories. For example, {@code **}{@code /head.ftl}
+     *       matches {@code foo/bar/head.ftl}, {@code foo/head.ftl} and {@code 
head.ftl} too. {@code **} must be either
+     *       preceded by {@code /} or be at the beginning of the glob. {@code 
**} must be either followed by {@code /} or be
+     *       at the end of the glob. When {@code **} is at the end of the 
glob, it also matches file names, like
+     *       {@code a/**} matches {@code a/b/c.ftl}. If the glob only consist 
of a {@code **}, it will be a match for
+     *       everything.
+     *   <li>{@code \} (backslash): Makes the next character non-special (a 
literal). For example {@code How\?.ftl} will
+     *       match {@code How?.ftl}, but not {@code HowX.ftl}. Naturally, two 
backslashes produce one literal backslash. 
+     *   <li>{@code [}: Reserved for future purposes; can't be used
+     *   <li><code>{</code>: Reserved for future purposes; can't be used
+     * </ul>
+     * 
+     * @since 2.3.24
+     */
+    public static Pattern globToRegularExpression(String glob, boolean 
caseInsensitive) {
+        StringBuilder regex = new StringBuilder();
+        
+        int nextStart = 0;
+        boolean escaped = false;
+        int ln = glob.length();
+        for (int idx = 0; idx < ln; idx++) {
+            char c = glob.charAt(idx);
+            if (!escaped) {
+                if (c == '?') {
+                    appendLiteralGlobSection(regex, glob, nextStart, idx);
+                    regex.append("[^/]");
+                    nextStart = idx + 1;
+                } else if (c == '*') {
+                    appendLiteralGlobSection(regex, glob, nextStart, idx);
+                    if (idx + 1 < ln && glob.charAt(idx + 1) == '*') {
+                        if (!(idx == 0 || glob.charAt(idx - 1) == '/')) {
+                            throw new IllegalArgumentException(
+                                    "The \"**\" wildcard must be directly 
after a \"/\" or it must be at the "
+                                    + "beginning, in this glob: " + glob);
+                        }
+                        
+                        if (idx + 2 == ln) { // trailing "**"
+                            regex.append(".*");
+                            idx++;
+                        } else { // "**/"
+                            if (!(idx + 2 < ln && glob.charAt(idx + 2) == 
'/')) {
+                                throw new IllegalArgumentException(
+                                        "The \"**\" wildcard must be followed 
by \"/\", or must be at tehe end, "
+                                        + "in this glob: " + glob);
+                            }
+                            regex.append("(.*?/)*");
+                            idx += 2;  // "*/".length()
+                        }
+                    } else {
+                        regex.append("[^/]*");
+                    }
+                    nextStart = idx + 1;
+                } else if (c == '\\') {
+                    escaped = true;
+                } else if (c == '[' || c == '{') {
+                    throw new IllegalArgumentException(
+                            "The \"" + c + "\" glob operator is currently 
unsupported "
+                            + "(precede it with \\ for literal matching), "
+                            + "in this glob: " + glob);
+                }
+            } else {
+                escaped = false;
+            }
+        }
+        appendLiteralGlobSection(regex, glob, nextStart, glob.length());
+        
+        return Pattern.compile(regex.toString(), caseInsensitive ? 
Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE : 0);
+    }
+
+    private static void appendLiteralGlobSection(StringBuilder regex, String 
glob, int start, int end) {
+        if (start == end) return;
+        String part = unescapeLiteralGlobSection(glob.substring(start, end));
+        regex.append(Pattern.quote(part));
+    }
+
+    private static String unescapeLiteralGlobSection(String s) {
+        int backslashIdx = s.indexOf('\\');
+        if (backslashIdx == -1) {
+            return s;
+        }
+        int ln = s.length();
+        StringBuilder sb = new StringBuilder(ln - 1);
+        int nextStart = 0; 
+        do {
+            sb.append(s, nextStart, backslashIdx);
+            nextStart = backslashIdx + 1;
+        } while ((backslashIdx = s.indexOf('\\', nextStart + 1)) != -1);
+        if (nextStart < ln) {
+            sb.append(s, nextStart, ln);
+        }
+        return sb.toString();
+    }
+
+    public static String toFTLIdentifierReferenceAfterDot(String name) {
+        return FTLUtil.escapeIdentifier(name);
+    }
+
+    public static String toFTLTopLevelIdentifierReference(String name) {
+        return FTLUtil.escapeIdentifier(name);
+    }
+
+    public static String toFTLTopLevelTragetIdentifier(final String name) {
+        char quotationType = 0;
+        scanForQuotationType: for (int i = 0; i < name.length(); i++) {
+            final char c = name.charAt(i);
+            if (!(i == 0 ? FTLUtil.isNonEscapedIdentifierStart(c) : 
FTLUtil.isNonEscapedIdentifierPart(c)) && c != '@') {
+                if ((quotationType == 0 || quotationType == '\\') && (c == '-' 
|| c == '.' || c == ':')) {
+                    quotationType = '\\';
+                } else {
+                    quotationType = '"';
+                    break scanForQuotationType;
+                }
+            }
+        }
+        switch (quotationType) {
+        case 0:
+            return name;
+        case '"':
+            return FTLUtil.toStringLiteral(name);
+        case '\\':
+            return FTLUtil.escapeIdentifier(name);
+        default:
+            throw new BugException();
+        }
+    }
+
+    /**
+     * @return {@link ParsingConfiguration#CAMEL_CASE_NAMING_CONVENTION}, or 
{@link ParsingConfiguration#LEGACY_NAMING_CONVENTION}
+     *         or, {@link ParsingConfiguration#AUTO_DETECT_NAMING_CONVENTION} 
when undecidable.
+     */
+    public static int getIdentifierNamingConvention(String name) {
+        final int ln = name.length();
+        for (int i = 0; i < ln; i++) {
+            final char c = name.charAt(i);
+            if (c == '_') {
+                return ParsingConfiguration.LEGACY_NAMING_CONVENTION;
+            }
+            if (_StringUtil.isUpperUSASCII(c)) {
+                return ParsingConfiguration.CAMEL_CASE_NAMING_CONVENTION;
+            }
+        }
+        return ParsingConfiguration.AUTO_DETECT_NAMING_CONVENTION;
+    }
+
+    // [2.4] Won't be needed anymore
+    /**
+     * A deliberately very inflexible camel case to underscored converter; it 
must not convert improper camel case
+     * names to a proper underscored name.
+     */
+    public static String camelCaseToUnderscored(String camelCaseName) {
+        int i = 0;
+        while (i < camelCaseName.length() && 
Character.isLowerCase(camelCaseName.charAt(i))) {
+            i++;
+        }
+        if (i == camelCaseName.length()) {
+            // No conversion needed
+            return camelCaseName;
+        }
+        
+        StringBuilder sb = new StringBuilder();
+        sb.append(camelCaseName.substring(0, i));
+        while (i < camelCaseName.length()) {
+            final char c = camelCaseName.charAt(i);
+            if (_StringUtil.isUpperUSASCII(c)) {
+                sb.append('_');
+                sb.append(Character.toLowerCase(c));
+            } else {
+                sb.append(c);
+            }
+            i++;
+        }
+        return sb.toString();
+    }
+
+    public static boolean isASCIIDigit(char c) {
+        return c >= '0' && c <= '9';
+    }
+    
+    public static boolean isUpperUSASCII(char c) {
+        return c >= 'A' && c <= 'Z';
+    }
+
+    private static final Pattern NORMALIZE_EOLS_REGEXP = 
Pattern.compile("\\r\\n?+");
+
+    /**
+     * Converts all non UN*X End-Of-Line character sequences (CR and CRLF) to 
UN*X format (LF).
+     * Returns {@code null} for {@code null} input.
+     */
+    public static String normalizeEOLs(String s) {
+        if (s == null) {
+            return null;
+        }
+        return NORMALIZE_EOLS_REGEXP.matcher(s).replaceAll("\n");
+    }
+    
+}

http://git-wip-us.apache.org/repos/asf/incubator-freemarker/blob/3fd56062/freemarker-core/src/main/java/org/apache/freemarker/core/util/_UnmodifiableCompositeSet.java
----------------------------------------------------------------------
diff --git 
a/freemarker-core/src/main/java/org/apache/freemarker/core/util/_UnmodifiableCompositeSet.java
 
b/freemarker-core/src/main/java/org/apache/freemarker/core/util/_UnmodifiableCompositeSet.java
new file mode 100644
index 0000000..ab88f57
--- /dev/null
+++ 
b/freemarker-core/src/main/java/org/apache/freemarker/core/util/_UnmodifiableCompositeSet.java
@@ -0,0 +1,98 @@
+/*
+ * 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 org.apache.freemarker.core.util;
+
+import java.util.Iterator;
+import java.util.Set;
+
+/** Don't use this; used internally by FreeMarker, might changes without 
notice. */
+public class _UnmodifiableCompositeSet<E> extends _UnmodifiableSet<E> {
+    
+    private final Set<E> set1, set2;
+    
+    public _UnmodifiableCompositeSet(Set<E> set1, Set<E> set2) {
+        this.set1 = set1;
+        this.set2 = set2;
+    }
+
+    @Override
+    public Iterator<E> iterator() {
+        return new CompositeIterator();
+    }
+    
+    @Override
+    public boolean contains(Object o) {
+        return set1.contains(o) || set2.contains(o);
+    }
+
+    @Override
+    public int size() {
+        return set1.size() + set2.size();
+    }
+    
+    private class CompositeIterator implements Iterator<E> {
+
+        private Iterator<E> it1, it2;
+        private boolean it1Deplected;
+        
+        @Override
+        public boolean hasNext() {
+            if (!it1Deplected) {
+                if (it1 == null) {
+                    it1 = set1.iterator();
+                }
+                if (it1.hasNext()) {
+                    return true;
+                }
+                
+                it2 = set2.iterator();
+                it1 = null;
+                it1Deplected = true;
+                // Falls through
+            }
+            return it2.hasNext();
+        }
+
+        @Override
+        public E next() {
+            if (!it1Deplected) {
+                if (it1 == null) {
+                    it1 = set1.iterator();
+                }
+                if (it1.hasNext()) {
+                    return it1.next();
+                }
+                
+                it2 = set2.iterator();
+                it1 = null;
+                it1Deplected = true;
+                // Falls through
+            }
+            return it2.next();
+        }
+
+        @Override
+        public void remove() {
+            throw new UnsupportedOperationException();
+        }
+
+    }
+    
+}

http://git-wip-us.apache.org/repos/asf/incubator-freemarker/blob/3fd56062/freemarker-core/src/main/java/org/apache/freemarker/core/util/_UnmodifiableSet.java
----------------------------------------------------------------------
diff --git 
a/freemarker-core/src/main/java/org/apache/freemarker/core/util/_UnmodifiableSet.java
 
b/freemarker-core/src/main/java/org/apache/freemarker/core/util/_UnmodifiableSet.java
new file mode 100644
index 0000000..7e08815
--- /dev/null
+++ 
b/freemarker-core/src/main/java/org/apache/freemarker/core/util/_UnmodifiableSet.java
@@ -0,0 +1,47 @@
+/*
+ * 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 org.apache.freemarker.core.util;
+
+import java.util.AbstractSet;
+
+/** Don't use this; used internally by FreeMarker, might changes without 
notice. */
+public abstract class _UnmodifiableSet<E> extends AbstractSet<E> {
+
+    @Override
+    public boolean add(E o) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean remove(Object o) {
+        if (contains(o)) {
+            throw new UnsupportedOperationException();
+        }
+        return false;
+    }
+
+    @Override
+    public void clear() {
+        if (!isEmpty()) {
+            throw new UnsupportedOperationException();
+        }
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-freemarker/blob/3fd56062/freemarker-core/src/main/java/org/apache/freemarker/core/util/package.html
----------------------------------------------------------------------
diff --git 
a/freemarker-core/src/main/java/org/apache/freemarker/core/util/package.html 
b/freemarker-core/src/main/java/org/apache/freemarker/core/util/package.html
new file mode 100644
index 0000000..e90df61
--- /dev/null
+++ b/freemarker-core/src/main/java/org/apache/freemarker/core/util/package.html
@@ -0,0 +1,25 @@
+<!--
+  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.
+-->
+<html>
+<head>
+</head>
+<body bgcolor="white">
+<p>Various classes used by core FreeMarker code but might be useful outside of 
it too.</p>
+</body>
+</html>
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/incubator-freemarker/blob/3fd56062/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/InvalidFormatParametersException.java
----------------------------------------------------------------------
diff --git 
a/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/InvalidFormatParametersException.java
 
b/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/InvalidFormatParametersException.java
new file mode 100644
index 0000000..ba09574
--- /dev/null
+++ 
b/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/InvalidFormatParametersException.java
@@ -0,0 +1,37 @@
+/*
+ * 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 org.apache.freemarker.core.valueformat;
+
+/**
+ * Used when creating {@link TemplateDateFormat}-s and {@link 
TemplateNumberFormat}-s to indicate that the parameters
+ * part of the format string (like some kind of pattern) is malformed.
+ * 
+ * @since 2.3.24
+ */
+public final class InvalidFormatParametersException extends 
InvalidFormatStringException {
+    
+    public InvalidFormatParametersException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public InvalidFormatParametersException(String message) {
+        this(message, null);
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-freemarker/blob/3fd56062/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/InvalidFormatStringException.java
----------------------------------------------------------------------
diff --git 
a/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/InvalidFormatStringException.java
 
b/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/InvalidFormatStringException.java
new file mode 100644
index 0000000..05c7ed1
--- /dev/null
+++ 
b/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/InvalidFormatStringException.java
@@ -0,0 +1,37 @@
+/*
+ * 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 org.apache.freemarker.core.valueformat;
+
+/**
+ * Used when creating {@link TemplateDateFormat}-s and {@link 
TemplateNumberFormat}-s to indicate that the format
+ * string (like the value of the {@code dateFormat} setting) is malformed.
+ * 
+ * @since 2.3.24
+ */
+public abstract class InvalidFormatStringException extends 
TemplateValueFormatException {
+    
+    public InvalidFormatStringException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public InvalidFormatStringException(String message) {
+        this(message, null);
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-freemarker/blob/3fd56062/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/ParsingNotSupportedException.java
----------------------------------------------------------------------
diff --git 
a/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/ParsingNotSupportedException.java
 
b/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/ParsingNotSupportedException.java
new file mode 100644
index 0000000..08eba37
--- /dev/null
+++ 
b/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/ParsingNotSupportedException.java
@@ -0,0 +1,37 @@
+/*
+ * 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 org.apache.freemarker.core.valueformat;
+
+/**
+ * Thrown when the {@link TemplateValueFormat} doesn't support parsing, and 
parsing was invoked.
+ * 
+ * @since 2.3.24
+ */
+public class ParsingNotSupportedException extends TemplateValueFormatException 
{
+
+    public ParsingNotSupportedException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public ParsingNotSupportedException(String message) {
+        this(message, null);
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-freemarker/blob/3fd56062/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/TemplateDateFormat.java
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+/*
+ * 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 org.apache.freemarker.core.valueformat;
+
+import java.text.DateFormat;
+import java.util.Date;
+
+import org.apache.freemarker.core.Environment;
+import org.apache.freemarker.core.model.TemplateDateModel;
+import org.apache.freemarker.core.model.TemplateMarkupOutputModel;
+import org.apache.freemarker.core.model.TemplateModelException;
+
+/**
+ * Represents a date/time/dateTime format; used in templates for formatting 
and parsing with that format. This is
+ * similar to Java's {@link DateFormat}, but made to fit the requirements of 
FreeMarker. Also, it makes easier to define
+ * formats that can't be represented with Java's existing {@link DateFormat} 
implementations.
+ * 
+ * <p>
+ * Implementations need not be thread-safe if the {@link 
TemplateNumberFormatFactory} doesn't recycle them among
+ * different {@link Environment}-s. As far as FreeMarker's concerned, 
instances are bound to a single
+ * {@link Environment}, and {@link Environment}-s are thread-local objects.
+ * 
+ * @since 2.3.24
+ */
+public abstract class TemplateDateFormat extends TemplateValueFormat {
+    
+    /**
+     * @param dateModel
+     *            The date/time/dateTime to format; not {@code null}. Most 
implementations will just work with the return value of
+     *            {@link TemplateDateModel#getAsDate()}, but some may format 
differently depending on the properties of
+     *            a custom {@link TemplateDateModel} implementation.
+     * 
+     * @return The date/time/dateTime as text, with no escaping (like no HTML 
escaping); can't be {@code null}.
+     * 
+     * @throws TemplateValueFormatException
+     *             When a problem occurs during the formatting of the value. 
Notable subclass:
+     *             {@link UnknownDateTypeFormattingUnsupportedException}
+     * @throws TemplateModelException
+     *             Exception thrown by the {@code dateModel} object when 
calling its methods.
+     */
+    public abstract String formatToPlainText(TemplateDateModel dateModel)
+            throws TemplateValueFormatException, TemplateModelException;
+
+    /**
+     * Formats the model to markup instead of to plain text if the result 
markup will be more than just plain text
+     * escaped, otherwise falls back to formatting to plain text. If the 
markup result would be just the result of
+     * {@link #formatToPlainText(TemplateDateModel)} escaped, it must return 
the {@link String} that
+     * {@link #formatToPlainText(TemplateDateModel)} does.
+     * 
+     * <p>The implementation in {@link TemplateDateFormat} simply calls {@link 
#formatToPlainText(TemplateDateModel)}.
+     * 
+     * @return A {@link String} or a {@link TemplateMarkupOutputModel}; not 
{@code null}.
+     */
+    public Object format(TemplateDateModel dateModel) throws 
TemplateValueFormatException, TemplateModelException {
+        return formatToPlainText(dateModel);
+    }
+
+    /**
+     * Parsers a string to date/time/datetime, according to this format. Some 
format implementations may throw
+     * {@link ParsingNotSupportedException} here.
+     * 
+     * @param s
+     *            The string to parse
+     * @param dateType
+     *            The expected date type of the result. Not all {@link 
TemplateDateFormat}-s will care about this;
+     *            though those who return a {@link TemplateDateModel} instead 
of {@link Date} often will. When strings
+     *            are parsed via {@code ?date}, {@code ?time}, or {@code 
?datetime}, then this parameter is
+     *            {@link TemplateDateModel#DATE}, {@link 
TemplateDateModel#TIME}, or {@link TemplateDateModel#DATETIME},
+     *            respectively. This parameter rarely if ever {@link 
TemplateDateModel#UNKNOWN}, but the implementation
+     *            that cares about this parameter should be prepared for that. 
If nothing else, it should throw
+     *            {@link UnknownDateTypeParsingUnsupportedException} then.
+     * 
+     * @return The interpretation of the text either as a {@link Date} or 
{@link TemplateDateModel}. Typically, a
+     *         {@link Date}. {@link TemplateDateModel} is used if you have to 
attach some application-specific
+     *         meta-information thats also extracted during {@link 
#formatToPlainText(TemplateDateModel)} (so if you format
+     *         something and then parse it, you get back an equivalent 
result). It can't be {@code null}. Known issue
+     *         (at least in FTL 2): {@code ?date}/{@code ?time}/{@code 
?datetime}, when not invoked as a method, can't
+     *         return the {@link TemplateDateModel}, only the {@link Date} 
from inside it, hence the additional
+     *         application-specific meta-info will be lost.
+     */
+    public abstract Object parse(String s, int dateType) throws 
TemplateValueFormatException;
+    
+    /**
+     * Tells if this formatter should be re-created if the locale changes.
+     */
+    public abstract boolean isLocaleBound();
+
+    /**
+     * Tells if this formatter should be re-created if the time zone changes. 
Currently always {@code true}.
+     */
+    public abstract boolean isTimeZoneBound();
+        
+}

http://git-wip-us.apache.org/repos/asf/incubator-freemarker/blob/3fd56062/freemarker-core/src/main/java/org/apache/freemarker/core/valueformat/TemplateDateFormatFactory.java
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+/*
+ * 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 org.apache.freemarker.core.valueformat;
+
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Locale;
+import java.util.TimeZone;
+
+import org.apache.freemarker.core.CustomStateKey;
+import org.apache.freemarker.core.MutableProcessingConfiguration;
+import org.apache.freemarker.core.Configuration;
+import org.apache.freemarker.core.Environment;
+import org.apache.freemarker.core.model.TemplateDateModel;
+
+/**
+ * Factory for a certain kind of date/time/dateTime formatting ({@link 
TemplateDateFormat}). Usually a singleton
+ * (one-per-VM or one-per-{@link Configuration}), and so must be thread-safe.
+ * 
+ * @see MutableProcessingConfiguration#setCustomDateFormats(java.util.Map)
+ * 
+ * @since 2.3.24
+ */
+public abstract class TemplateDateFormatFactory extends 
TemplateValueFormatFactory {
+    
+    /**
+     * Returns a formatter for the given parameters.
+     * 
+     * <p>
+     * The returned formatter can be a new instance or a reused (cached) 
instance. Note that {@link Environment} itself
+     * caches the returned instances, though that cache is lost with the 
{@link Environment} (i.e., when the top-level
+     * template execution ends), also it might flushes lot of entries if the 
locale or time zone is changed during
+     * template execution. So caching on the factory level is still useful, 
unless creating the formatters is
+     * sufficiently cheap.
+     * 
+     * @param params
+     *            The string that further describes how the format should 
look. For example, when the
+     *            {@link MutableProcessingConfiguration#getDateFormat() 
dateFormat} is {@code "@fooBar 1, 2"}, then it will be
+     *            {@code "1, 2"} (and {@code "@fooBar"} selects the factory). 
The format of this string is up to the
+     *            {@link TemplateDateFormatFactory} implementation. Not {@code 
null}, often an empty string.
+     * @param dateType
+     *            {@link TemplateDateModel#DATE}, {@link 
TemplateDateModel#TIME}, {@link TemplateDateModel#DATETIME} or
+     *            {@link TemplateDateModel#UNKNOWN}. Supporting {@link 
TemplateDateModel#UNKNOWN} is not necessary, in
+     *            which case the method should throw an {@link 
UnknownDateTypeFormattingUnsupportedException} exception.
+     * @param locale
+     *            The locale to format for. Not {@code null}. The resulting 
format should be bound to this locale
+     *            forever (i.e. locale changes in the {@link Environment} must 
not be followed).
+     * @param timeZone
+     *            The time zone to format for. Not {@code null}. The resulting 
format must be bound to this time zone
+     *            forever (i.e. time zone changes in the {@link Environment} 
must not be followed).
+     * @param zonelessInput
+     *            Indicates that the input Java {@link Date} is not from a 
time zone aware source. When this is
+     *            {@code true}, the formatters shouldn't override the time 
zone provided to its constructor (most
+     *            formatters don't do that anyway), and it shouldn't show the 
time zone, if it can hide it (like a
+     *            {@link SimpleDateFormat} pattern-based formatter may can't 
do that, as the pattern prescribes what to
+     *            show).
+     *            <p>
+     *            As of FreeMarker 2.3.21, this is {@code true} exactly when 
the date is an SQL "date without time of
+     *            the day" (i.e., a {@link java.sql.Date java.sql.Date}) or an 
SQL "time of the day" value (i.e., a
+     *            {@link java.sql.Time java.sql.Time}, although this rule can 
change in future, depending on
+     *            configuration settings and such, so you shouldn't rely on 
this rule, just accept what this parameter
+     *            says.
+     * @param env
+     *            The runtime environment from which the formatting was 
called. This is mostly meant to be used for
+     *            {@link Environment#getCustomState(CustomStateKey)}.
+     * 
+     * @throws TemplateValueFormatException
+     *             If any problem occurs while parsing/getting the format. 
Notable subclasses:
+     *             {@link InvalidFormatParametersException} if {@code params} 
is malformed;
+     *             {@link UnknownDateTypeFormattingUnsupportedException} if 
{@code dateType} is
+     *             {@link TemplateDateModel#UNKNOWN} and that's unsupported by 
this factory.
+     */
+    public abstract TemplateDateFormat get(
+            String params,
+            int dateType, Locale locale, TimeZone timeZone, boolean 
zonelessInput,
+            Environment env)
+                    throws TemplateValueFormatException;
+
+}


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