001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.lang3;
018
019import java.io.IOException;
020import java.io.Writer;
021
022import org.apache.commons.lang3.text.translate.AggregateTranslator;
023import org.apache.commons.lang3.text.translate.CharSequenceTranslator;
024import org.apache.commons.lang3.text.translate.EntityArrays;
025import org.apache.commons.lang3.text.translate.JavaUnicodeEscaper;
026import org.apache.commons.lang3.text.translate.LookupTranslator;
027import org.apache.commons.lang3.text.translate.NumericEntityEscaper;
028import org.apache.commons.lang3.text.translate.NumericEntityUnescaper;
029import org.apache.commons.lang3.text.translate.OctalUnescaper;
030import org.apache.commons.lang3.text.translate.UnicodeUnescaper;
031import org.apache.commons.lang3.text.translate.UnicodeUnpairedSurrogateRemover;
032
033/**
034 * Escapes and unescapes {@link String}s for
035 * Java, Java Script, HTML and XML.
036 *
037 * <p>#ThreadSafe#</p>
038 * @since 2.0
039 * @deprecated As of 3.6, use Apache Commons Text
040 * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/StringEscapeUtils.html">
041 * StringEscapeUtils</a> instead
042 */
043@Deprecated
044public class StringEscapeUtils {
045
046    /* ESCAPE TRANSLATORS */
047
048    // TODO: Create a parent class - 'SinglePassTranslator' ?
049    //       It would handle the index checking + length returning,
050    //       and could also have an optimization check method.
051    static class CsvEscaper extends CharSequenceTranslator {
052
053        private static final char CSV_DELIMITER = ',';
054        private static final char CSV_QUOTE = '"';
055        private static final String CSV_QUOTE_STR = String.valueOf(CSV_QUOTE);
056        private static final char[] CSV_SEARCH_CHARS = { CSV_DELIMITER, CSV_QUOTE, CharUtils.CR, CharUtils.LF };
057
058        @Override
059        public int translate(final CharSequence input, final int index, final Writer out) throws IOException {
060
061            if (index != 0) {
062                throw new IllegalStateException("CsvEscaper should never reach the [1] index");
063            }
064
065            if (StringUtils.containsNone(input.toString(), CSV_SEARCH_CHARS)) {
066                out.write(input.toString());
067            } else {
068                out.write(CSV_QUOTE);
069                out.write(StringUtils.replace(input.toString(), CSV_QUOTE_STR, CSV_QUOTE_STR + CSV_QUOTE_STR));
070                out.write(CSV_QUOTE);
071            }
072            return Character.codePointCount(input, 0, input.length());
073        }
074    }
075
076    static class CsvUnescaper extends CharSequenceTranslator {
077
078        private static final char CSV_DELIMITER = ',';
079        private static final char CSV_QUOTE = '"';
080        private static final String CSV_QUOTE_STR = String.valueOf(CSV_QUOTE);
081        private static final char[] CSV_SEARCH_CHARS = {CSV_DELIMITER, CSV_QUOTE, CharUtils.CR, CharUtils.LF};
082
083        @Override
084        public int translate(final CharSequence input, final int index, final Writer out) throws IOException {
085
086            if (index != 0) {
087                throw new IllegalStateException("CsvUnescaper should never reach the [1] index");
088            }
089
090            if ( input.charAt(0) != CSV_QUOTE || input.charAt(input.length() - 1) != CSV_QUOTE ) {
091                out.write(input.toString());
092                return Character.codePointCount(input, 0, input.length());
093            }
094
095            // strip quotes
096            final String quoteless = input.subSequence(1, input.length() - 1).toString();
097
098            if ( StringUtils.containsAny(quoteless, CSV_SEARCH_CHARS) ) {
099                // deal with escaped quotes; ie) ""
100                out.write(StringUtils.replace(quoteless, CSV_QUOTE_STR + CSV_QUOTE_STR, CSV_QUOTE_STR));
101            } else {
102                out.write(input.toString());
103            }
104            return Character.codePointCount(input, 0, input.length());
105        }
106    }
107
108    /**
109     * Translator object for escaping Java.
110     *
111     * While {@link #escapeJava(String)} is the expected method of use, this
112     * object allows the Java escaping functionality to be used
113     * as the foundation for a custom translator.
114     *
115     * @since 3.0
116     */
117    public static final CharSequenceTranslator ESCAPE_JAVA =
118          new LookupTranslator(
119            new String[][] {
120              {"\"", "\\\""},
121              {"\\", "\\\\"},
122          }).with(
123            new LookupTranslator(EntityArrays.JAVA_CTRL_CHARS_ESCAPE())
124          ).with(
125            JavaUnicodeEscaper.outsideOf(32, 0x7f)
126        );
127
128    /**
129     * Translator object for escaping EcmaScript/JavaScript.
130     *
131     * While {@link #escapeEcmaScript(String)} is the expected method of use, this
132     * object allows the EcmaScript escaping functionality to be used
133     * as the foundation for a custom translator.
134     *
135     * @since 3.0
136     */
137    public static final CharSequenceTranslator ESCAPE_ECMASCRIPT =
138        new AggregateTranslator(
139            new LookupTranslator(
140                      new String[][] {
141                            {"'", "\\'"},
142                            {"\"", "\\\""},
143                            {"\\", "\\\\"},
144                            {"/", "\\/"}
145                      }),
146            new LookupTranslator(EntityArrays.JAVA_CTRL_CHARS_ESCAPE()),
147            JavaUnicodeEscaper.outsideOf(32, 0x7f)
148        );
149
150    /**
151     * Translator object for escaping Json.
152     *
153     * While {@link #escapeJson(String)} is the expected method of use, this
154     * object allows the Json escaping functionality to be used
155     * as the foundation for a custom translator.
156     *
157     * @since 3.2
158     */
159    public static final CharSequenceTranslator ESCAPE_JSON =
160        new AggregateTranslator(
161            new LookupTranslator(
162                      new String[][] {
163                            {"\"", "\\\""},
164                            {"\\", "\\\\"},
165                            {"/", "\\/"}
166                      }),
167            new LookupTranslator(EntityArrays.JAVA_CTRL_CHARS_ESCAPE()),
168            JavaUnicodeEscaper.outsideOf(32, 0x7f)
169        );
170
171    /**
172     * Translator object for escaping XML.
173     *
174     * While {@link #escapeXml(String)} is the expected method of use, this
175     * object allows the XML escaping functionality to be used
176     * as the foundation for a custom translator.
177     *
178     * @since 3.0
179     * @deprecated use {@link #ESCAPE_XML10} or {@link #ESCAPE_XML11} instead.
180     */
181    @Deprecated
182    public static final CharSequenceTranslator ESCAPE_XML =
183        new AggregateTranslator(
184            new LookupTranslator(EntityArrays.BASIC_ESCAPE()),
185            new LookupTranslator(EntityArrays.APOS_ESCAPE())
186        );
187
188    /**
189     * Translator object for escaping XML 1.0.
190     *
191     * While {@link #escapeXml10(String)} is the expected method of use, this
192     * object allows the XML escaping functionality to be used
193     * as the foundation for a custom translator.
194     *
195     * @since 3.3
196     */
197    public static final CharSequenceTranslator ESCAPE_XML10 =
198        new AggregateTranslator(
199            new LookupTranslator(EntityArrays.BASIC_ESCAPE()),
200            new LookupTranslator(EntityArrays.APOS_ESCAPE()),
201            new LookupTranslator(
202                    new String[][] {
203                            { "\u0000", StringUtils.EMPTY },
204                            { "\u0001", StringUtils.EMPTY },
205                            { "\u0002", StringUtils.EMPTY },
206                            { "\u0003", StringUtils.EMPTY },
207                            { "\u0004", StringUtils.EMPTY },
208                            { "\u0005", StringUtils.EMPTY },
209                            { "\u0006", StringUtils.EMPTY },
210                            { "\u0007", StringUtils.EMPTY },
211                            { "\u0008", StringUtils.EMPTY },
212                            { "\u000b", StringUtils.EMPTY },
213                            { "\u000c", StringUtils.EMPTY },
214                            { "\u000e", StringUtils.EMPTY },
215                            { "\u000f", StringUtils.EMPTY },
216                            { "\u0010", StringUtils.EMPTY },
217                            { "\u0011", StringUtils.EMPTY },
218                            { "\u0012", StringUtils.EMPTY },
219                            { "\u0013", StringUtils.EMPTY },
220                            { "\u0014", StringUtils.EMPTY },
221                            { "\u0015", StringUtils.EMPTY },
222                            { "\u0016", StringUtils.EMPTY },
223                            { "\u0017", StringUtils.EMPTY },
224                            { "\u0018", StringUtils.EMPTY },
225                            { "\u0019", StringUtils.EMPTY },
226                            { "\u001a", StringUtils.EMPTY },
227                            { "\u001b", StringUtils.EMPTY },
228                            { "\u001c", StringUtils.EMPTY },
229                            { "\u001d", StringUtils.EMPTY },
230                            { "\u001e", StringUtils.EMPTY },
231                            { "\u001f", StringUtils.EMPTY },
232                            { "\ufffe", StringUtils.EMPTY },
233                            { "\uffff", StringUtils.EMPTY }
234                    }),
235            NumericEntityEscaper.between(0x7f, 0x84),
236            NumericEntityEscaper.between(0x86, 0x9f),
237            new UnicodeUnpairedSurrogateRemover()
238        );
239
240    /**
241     * Translator object for escaping XML 1.1.
242     *
243     * While {@link #escapeXml11(String)} is the expected method of use, this
244     * object allows the XML escaping functionality to be used
245     * as the foundation for a custom translator.
246     *
247     * @since 3.3
248     */
249    public static final CharSequenceTranslator ESCAPE_XML11 =
250        new AggregateTranslator(
251            new LookupTranslator(EntityArrays.BASIC_ESCAPE()),
252            new LookupTranslator(EntityArrays.APOS_ESCAPE()),
253            new LookupTranslator(
254                    new String[][] {
255                            { "\u0000", StringUtils.EMPTY },
256                            { "\u000b", "&#11;" },
257                            { "\u000c", "&#12;" },
258                            { "\ufffe", StringUtils.EMPTY },
259                            { "\uffff", StringUtils.EMPTY }
260                    }),
261            NumericEntityEscaper.between(0x1, 0x8),
262            NumericEntityEscaper.between(0xe, 0x1f),
263            NumericEntityEscaper.between(0x7f, 0x84),
264            NumericEntityEscaper.between(0x86, 0x9f),
265            new UnicodeUnpairedSurrogateRemover()
266        );
267
268    /**
269     * Translator object for escaping HTML version 3.0.
270     *
271     * While {@link #escapeHtml3(String)} is the expected method of use, this
272     * object allows the HTML escaping functionality to be used
273     * as the foundation for a custom translator.
274     *
275     * @since 3.0
276     */
277    public static final CharSequenceTranslator ESCAPE_HTML3 =
278        new AggregateTranslator(
279            new LookupTranslator(EntityArrays.BASIC_ESCAPE()),
280            new LookupTranslator(EntityArrays.ISO8859_1_ESCAPE())
281        );
282
283    /**
284     * Translator object for escaping HTML version 4.0.
285     *
286     * While {@link #escapeHtml4(String)} is the expected method of use, this
287     * object allows the HTML escaping functionality to be used
288     * as the foundation for a custom translator.
289     *
290     * @since 3.0
291     */
292    public static final CharSequenceTranslator ESCAPE_HTML4 =
293        new AggregateTranslator(
294            new LookupTranslator(EntityArrays.BASIC_ESCAPE()),
295            new LookupTranslator(EntityArrays.ISO8859_1_ESCAPE()),
296            new LookupTranslator(EntityArrays.HTML40_EXTENDED_ESCAPE())
297        );
298
299    /* UNESCAPE TRANSLATORS */
300
301    /**
302     * Translator object for escaping individual Comma Separated Values.
303     *
304     * While {@link #escapeCsv(String)} is the expected method of use, this
305     * object allows the CSV escaping functionality to be used
306     * as the foundation for a custom translator.
307     *
308     * @since 3.0
309     */
310    public static final CharSequenceTranslator ESCAPE_CSV = new CsvEscaper();
311
312    /**
313     * Translator object for unescaping escaped Java.
314     *
315     * While {@link #unescapeJava(String)} is the expected method of use, this
316     * object allows the Java unescaping functionality to be used
317     * as the foundation for a custom translator.
318     *
319     * @since 3.0
320     */
321    // TODO: throw "illegal character: \92" as an Exception if a \ on the end of the Java (as per the compiler)?
322    public static final CharSequenceTranslator UNESCAPE_JAVA =
323        new AggregateTranslator(
324            new OctalUnescaper(),     // .between('\1', '\377'),
325            new UnicodeUnescaper(),
326            new LookupTranslator(EntityArrays.JAVA_CTRL_CHARS_UNESCAPE()),
327            new LookupTranslator(
328                      new String[][] {
329                            {"\\\\", "\\"},
330                            {"\\\"", "\""},
331                            {"\\'", "'"},
332                            {"\\", ""}
333                      })
334        );
335
336    /**
337     * Translator object for unescaping escaped EcmaScript.
338     *
339     * While {@link #unescapeEcmaScript(String)} is the expected method of use, this
340     * object allows the EcmaScript unescaping functionality to be used
341     * as the foundation for a custom translator.
342     *
343     * @since 3.0
344     */
345    public static final CharSequenceTranslator UNESCAPE_ECMASCRIPT = UNESCAPE_JAVA;
346
347    /**
348     * Translator object for unescaping escaped Json.
349     *
350     * While {@link #unescapeJson(String)} is the expected method of use, this
351     * object allows the Json unescaping functionality to be used
352     * as the foundation for a custom translator.
353     *
354     * @since 3.2
355     */
356    public static final CharSequenceTranslator UNESCAPE_JSON = UNESCAPE_JAVA;
357
358    /**
359     * Translator object for unescaping escaped HTML 3.0.
360     *
361     * While {@link #unescapeHtml3(String)} is the expected method of use, this
362     * object allows the HTML unescaping functionality to be used
363     * as the foundation for a custom translator.
364     *
365     * @since 3.0
366     */
367    public static final CharSequenceTranslator UNESCAPE_HTML3 =
368        new AggregateTranslator(
369            new LookupTranslator(EntityArrays.BASIC_UNESCAPE()),
370            new LookupTranslator(EntityArrays.ISO8859_1_UNESCAPE()),
371            new NumericEntityUnescaper()
372        );
373
374    /**
375     * Translator object for unescaping escaped HTML 4.0.
376     *
377     * While {@link #unescapeHtml4(String)} is the expected method of use, this
378     * object allows the HTML unescaping functionality to be used
379     * as the foundation for a custom translator.
380     *
381     * @since 3.0
382     */
383    public static final CharSequenceTranslator UNESCAPE_HTML4 =
384        new AggregateTranslator(
385            new LookupTranslator(EntityArrays.BASIC_UNESCAPE()),
386            new LookupTranslator(EntityArrays.ISO8859_1_UNESCAPE()),
387            new LookupTranslator(EntityArrays.HTML40_EXTENDED_UNESCAPE()),
388            new NumericEntityUnescaper()
389        );
390
391    /**
392     * Translator object for unescaping escaped XML.
393     *
394     * While {@link #unescapeXml(String)} is the expected method of use, this
395     * object allows the XML unescaping functionality to be used
396     * as the foundation for a custom translator.
397     *
398     * @since 3.0
399     */
400    public static final CharSequenceTranslator UNESCAPE_XML =
401        new AggregateTranslator(
402            new LookupTranslator(EntityArrays.BASIC_UNESCAPE()),
403            new LookupTranslator(EntityArrays.APOS_UNESCAPE()),
404            new NumericEntityUnescaper()
405        );
406
407    /**
408     * Translator object for unescaping escaped Comma Separated Value entries.
409     *
410     * While {@link #unescapeCsv(String)} is the expected method of use, this
411     * object allows the CSV unescaping functionality to be used
412     * as the foundation for a custom translator.
413     *
414     * @since 3.0
415     */
416    public static final CharSequenceTranslator UNESCAPE_CSV = new CsvUnescaper();
417
418    /* Helper functions */
419
420    /**
421     * Returns a {@link String} value for a CSV column enclosed in double quotes,
422     * if required.
423     *
424     * <p>If the value contains a comma, newline or double quote, then the
425     *    String value is returned enclosed in double quotes.</p>
426     *
427     * <p>Any double quote characters in the value are escaped with another double quote.</p>
428     *
429     * <p>If the value does not contain a comma, newline or double quote, then the
430     *    String value is returned unchanged.</p>
431     *
432     * see <a href="https://en.wikipedia.org/wiki/Comma-separated_values">Wikipedia</a> and
433     * <a href="https://datatracker.ietf.org/doc/html/rfc4180">RFC 4180</a>.
434     *
435     * @param input the input CSV column String, may be null
436     * @return the input String, enclosed in double quotes if the value contains a comma,
437     * newline or double quote, {@code null} if null string input
438     * @since 2.4
439     */
440    public static final String escapeCsv(final String input) {
441        return ESCAPE_CSV.translate(input);
442    }
443
444    /**
445     * Escapes the characters in a {@link String} using EcmaScript String rules.
446     * <p>Escapes any values it finds into their EcmaScript String form.
447     * Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.) </p>
448     *
449     * <p>So a tab becomes the characters {@code '\\'} and
450     * {@code 't'}.</p>
451     *
452     * <p>The only difference between Java strings and EcmaScript strings
453     * is that in EcmaScript, a single quote and forward-slash (/) are escaped.</p>
454     *
455     * <p>Note that EcmaScript is best known by the JavaScript and ActionScript dialects.</p>
456     *
457     * <p>Example:</p>
458     * <pre>
459     * input string: He didn't say, "Stop!"
460     * output string: He didn\'t say, \"Stop!\"
461     * </pre>
462     *
463     * @param input  String to escape values in, may be null
464     * @return String with escaped values, {@code null} if null string input
465     *
466     * @since 3.0
467     */
468    public static final String escapeEcmaScript(final String input) {
469        return ESCAPE_ECMASCRIPT.translate(input);
470    }
471
472    /**
473     * Escapes the characters in a {@link String} using HTML entities.
474     * <p>Supports only the HTML 3.0 entities.</p>
475     *
476     * @param input  the {@link String} to escape, may be null
477     * @return a new escaped {@link String}, {@code null} if null string input
478     *
479     * @since 3.0
480     */
481    public static final String escapeHtml3(final String input) {
482        return ESCAPE_HTML3.translate(input);
483    }
484
485    /**
486     * Escapes the characters in a {@link String} using HTML entities.
487     *
488     * <p>
489     * For example:
490     * </p>
491     * <p>{@code "bread" &amp; "butter"}</p>
492     * becomes:
493     * <p>
494     * {@code &amp;quot;bread&amp;quot; &amp;amp; &amp;quot;butter&amp;quot;}.
495     * </p>
496     *
497     * <p>Supports all known HTML 4.0 entities, including funky accents.
498     * Note that the commonly used apostrophe escape character (&amp;apos;)
499     * is not a legal entity and so is not supported).</p>
500     *
501     * @param input  the {@link String} to escape, may be null
502     * @return a new escaped {@link String}, {@code null} if null string input
503     *
504     * @see <a href="https://web.archive.org/web/20060225074150/https://hotwired.lycos.com/webmonkey/reference/special_characters/">ISO Entities</a>
505     * @see <a href="https://www.w3.org/TR/REC-html32#latin1">HTML 3.2 Character Entities for ISO Latin-1</a>
506     * @see <a href="https://www.w3.org/TR/REC-html40/sgml/entities.html">HTML 4.0 Character entity references</a>
507     * @see <a href="https://www.w3.org/TR/html401/charset.html#h-5.3">HTML 4.01 Character References</a>
508     * @see <a href="https://www.w3.org/TR/html401/charset.html#code-position">HTML 4.01 Code positions</a>
509     *
510     * @since 3.0
511     */
512    public static final String escapeHtml4(final String input) {
513        return ESCAPE_HTML4.translate(input);
514    }
515
516    /**
517     * Escapes the characters in a {@link String} using Java String rules.
518     *
519     * <p>Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.) </p>
520     *
521     * <p>So a tab becomes the characters {@code '\\'} and
522     * {@code 't'}.</p>
523     *
524     * <p>The only difference between Java strings and JavaScript strings
525     * is that in JavaScript, a single quote and forward-slash (/) are escaped.</p>
526     *
527     * <p>Example:</p>
528     * <pre>
529     * input string: He didn't say, "Stop!"
530     * output string: He didn't say, \"Stop!\"
531     * </pre>
532     *
533     * @param input  String to escape values in, may be null
534     * @return String with escaped values, {@code null} if null string input
535     */
536    public static final String escapeJava(final String input) {
537        return ESCAPE_JAVA.translate(input);
538    }
539
540    /**
541     * Escapes the characters in a {@link String} using Json String rules.
542     * <p>Escapes any values it finds into their Json String form.
543     * Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.) </p>
544     *
545     * <p>So a tab becomes the characters {@code '\\'} and
546     * {@code 't'}.</p>
547     *
548     * <p>The only difference between Java strings and Json strings
549     * is that in Json, forward-slash (/) is escaped.</p>
550     *
551     * <p>See https://www.ietf.org/rfc/rfc4627.txt for further details.</p>
552     *
553     * <p>Example:</p>
554     * <pre>
555     * input string: He didn't say, "Stop!"
556     * output string: He didn't say, \"Stop!\"
557     * </pre>
558     *
559     * @param input  String to escape values in, may be null
560     * @return String with escaped values, {@code null} if null string input
561     *
562     * @since 3.2
563     */
564    public static final String escapeJson(final String input) {
565        return ESCAPE_JSON.translate(input);
566    }
567
568    /**
569     * Escapes the characters in a {@link String} using XML entities.
570     *
571     * <p>For example: {@code "bread" & "butter"} =&gt;
572     * {@code &quot;bread&quot; &amp; &quot;butter&quot;}.
573     * </p>
574     *
575     * <p>Supports only the five basic XML entities (gt, lt, quot, amp, apos).
576     * Does not support DTDs or external entities.</p>
577     *
578     * <p>Note that Unicode characters greater than 0x7f are as of 3.0, no longer
579     *    escaped. If you still wish this functionality, you can achieve it
580     *    via the following:
581     * {@code StringEscapeUtils.ESCAPE_XML.with( NumericEntityEscaper.between(0x7f, Integer.MAX_VALUE) );}</p>
582     *
583     * @param input  the {@link String} to escape, may be null
584     * @return a new escaped {@link String}, {@code null} if null string input
585     * @see #unescapeXml(String)
586     * @deprecated use {@link #escapeXml10(java.lang.String)} or {@link #escapeXml11(java.lang.String)} instead.
587     */
588    @Deprecated
589    public static final String escapeXml(final String input) {
590        return ESCAPE_XML.translate(input);
591    }
592
593    /**
594     * Escapes the characters in a {@link String} using XML entities.
595     *
596     * <p>For example: {@code "bread" & "butter"} =&gt;
597     * {@code &quot;bread&quot; &amp; &quot;butter&quot;}.
598     * </p>
599     *
600     * <p>Note that XML 1.0 is a text-only format: it cannot represent control
601     * characters or unpaired Unicode surrogate code points, even after escaping.
602     * {@code escapeXml10} will remove characters that do not fit in the
603     * following ranges:</p>
604     *
605     * <p>{@code #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]}</p>
606     *
607     * <p>Though not strictly necessary, {@code escapeXml10} will escape
608     * characters in the following ranges:</p>
609     *
610     * <p>{@code [#x7F-#x84] | [#x86-#x9F]}</p>
611     *
612     * <p>The returned string can be inserted into a valid XML 1.0 or XML 1.1
613     * document. If you want to allow more non-text characters in an XML 1.1
614     * document, use {@link #escapeXml11(String)}.</p>
615     *
616     * @param input  the {@link String} to escape, may be null
617     * @return a new escaped {@link String}, {@code null} if null string input
618     * @see #unescapeXml(String)
619     * @since 3.3
620     */
621    public static String escapeXml10(final String input) {
622        return ESCAPE_XML10.translate(input);
623    }
624
625    /**
626     * Escapes the characters in a {@link String} using XML entities.
627     *
628     * <p>For example: {@code "bread" & "butter"} =&gt;
629     * {@code &quot;bread&quot; &amp; &quot;butter&quot;}.
630     * </p>
631     *
632     * <p>XML 1.1 can represent certain control characters, but it cannot represent
633     * the null byte or unpaired Unicode surrogate code points, even after escaping.
634     * {@code escapeXml11} will remove characters that do not fit in the following
635     * ranges:</p>
636     *
637     * <p>{@code [#x1-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]}</p>
638     *
639     * <p>{@code escapeXml11} will escape characters in the following ranges:</p>
640     *
641     * <p>{@code [#x1-#x8] | [#xB-#xC] | [#xE-#x1F] | [#x7F-#x84] | [#x86-#x9F]}</p>
642     *
643     * <p>The returned string can be inserted into a valid XML 1.1 document. Do not
644     * use it for XML 1.0 documents.</p>
645     *
646     * @param input  the {@link String} to escape, may be null
647     * @return a new escaped {@link String}, {@code null} if null string input
648     * @see #unescapeXml(String)
649     * @since 3.3
650     */
651    public static String escapeXml11(final String input) {
652        return ESCAPE_XML11.translate(input);
653    }
654
655    /**
656     * Returns a {@link String} value for an unescaped CSV column.
657     *
658     * <p>If the value is enclosed in double quotes, and contains a comma, newline
659     *    or double quote, then quotes are removed.
660     * </p>
661     *
662     * <p>Any double quote escaped characters (a pair of double quotes) are unescaped
663     *    to just one double quote.</p>
664     *
665     * <p>If the value is not enclosed in double quotes, or is and does not contain a
666     *    comma, newline or double quote, then the String value is returned unchanged.</p>
667     *
668     * see <a href="https://en.wikipedia.org/wiki/Comma-separated_values">Wikipedia</a> and
669     * <a href="https://datatracker.ietf.org/doc/html/rfc4180">RFC 4180</a>.
670     *
671     * @param input the input CSV column String, may be null
672     * @return the input String, with enclosing double quotes removed and embedded double
673     * quotes unescaped, {@code null} if null string input
674     * @since 2.4
675     */
676    public static final String unescapeCsv(final String input) {
677        return UNESCAPE_CSV.translate(input);
678    }
679
680    /**
681     * Unescapes any EcmaScript literals found in the {@link String}.
682     *
683     * <p>For example, it will turn a sequence of {@code '\'} and {@code 'n'}
684     * into a newline character, unless the {@code '\'} is preceded by another
685     * {@code '\'}.</p>
686     *
687     * @see #unescapeJava(String)
688     * @param input  the {@link String} to unescape, may be null
689     * @return A new unescaped {@link String}, {@code null} if null string input
690     *
691     * @since 3.0
692     */
693    public static final String unescapeEcmaScript(final String input) {
694        return UNESCAPE_ECMASCRIPT.translate(input);
695    }
696
697    /**
698     * Unescapes a string containing entity escapes to a string
699     * containing the actual Unicode characters corresponding to the
700     * escapes. Supports only HTML 3.0 entities.
701     *
702     * @param input  the {@link String} to unescape, may be null
703     * @return a new unescaped {@link String}, {@code null} if null string input
704     *
705     * @since 3.0
706     */
707    public static final String unescapeHtml3(final String input) {
708        return UNESCAPE_HTML3.translate(input);
709    }
710
711    /**
712     * Unescapes a string containing entity escapes to a string
713     * containing the actual Unicode characters corresponding to the
714     * escapes. Supports HTML 4.0 entities.
715     *
716     * <p>For example, the string {@code "&lt;Fran&ccedil;ais&gt;"}
717     * will become {@code "<Français>"}</p>
718     *
719     * <p>If an entity is unrecognized, it is left alone, and inserted
720     * verbatim into the result string. e.g. {@code "&gt;&zzzz;x"} will
721     * become {@code ">&zzzz;x"}.</p>
722     *
723     * @param input  the {@link String} to unescape, may be null
724     * @return a new unescaped {@link String}, {@code null} if null string input
725     *
726     * @since 3.0
727     */
728    public static final String unescapeHtml4(final String input) {
729        return UNESCAPE_HTML4.translate(input);
730    }
731
732    /**
733     * Unescapes any Java literals found in the {@link String}.
734     * For example, it will turn a sequence of {@code '\'} and
735     * {@code 'n'} into a newline character, unless the {@code '\'}
736     * is preceded by another {@code '\'}.
737     *
738     * @param input  the {@link String} to unescape, may be null
739     * @return a new unescaped {@link String}, {@code null} if null string input
740     */
741    public static final String unescapeJava(final String input) {
742        return UNESCAPE_JAVA.translate(input);
743    }
744
745    /**
746     * Unescapes any Json literals found in the {@link String}.
747     *
748     * <p>For example, it will turn a sequence of {@code '\'} and {@code 'n'}
749     * into a newline character, unless the {@code '\'} is preceded by another
750     * {@code '\'}.</p>
751     *
752     * @see #unescapeJava(String)
753     * @param input  the {@link String} to unescape, may be null
754     * @return A new unescaped {@link String}, {@code null} if null string input
755     *
756     * @since 3.2
757     */
758    public static final String unescapeJson(final String input) {
759        return UNESCAPE_JSON.translate(input);
760    }
761
762
763    /**
764     * Unescapes a string containing XML entity escapes to a string
765     * containing the actual Unicode characters corresponding to the
766     * escapes.
767     *
768     * <p>Supports only the five basic XML entities (gt, lt, quot, amp, apos).
769     * Does not support DTDs or external entities.</p>
770     *
771     * <p>Note that numerical \\u Unicode codes are unescaped to their respective
772     *    Unicode characters. This may change in future releases.</p>
773     *
774     * @param input  the {@link String} to unescape, may be null
775     * @return a new unescaped {@link String}, {@code null} if null string input
776     * @see #escapeXml(String)
777     * @see #escapeXml10(String)
778     * @see #escapeXml11(String)
779     */
780    public static final String unescapeXml(final String input) {
781        return UNESCAPE_XML.translate(input);
782    }
783
784    /**
785     * {@link StringEscapeUtils} instances should NOT be constructed in
786     * standard programming.
787     *
788     * <p>Instead, the class should be used as:</p>
789     * <pre>StringEscapeUtils.escapeJava("foo");</pre>
790     *
791     * <p>This constructor is public to permit tools that require a JavaBean
792     * instance to operate.</p>
793     */
794    public StringEscapeUtils() {
795    }
796
797}