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 *      https://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 *
039 * @since 2.0
040 * @deprecated As of 3.6, use Apache Commons Text
041 * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/StringEscapeUtils.html">
042 * StringEscapeUtils</a> instead.
043 */
044@Deprecated
045public class StringEscapeUtils {
046
047    /* ESCAPE TRANSLATORS */
048
049    private static final class CsvEscaper extends CharSequenceTranslator {
050
051        private static final char CSV_DELIMITER = ',';
052        private static final char CSV_QUOTE = '"';
053        private static final String CSV_QUOTE_STR = String.valueOf(CSV_QUOTE);
054        private static final char[] CSV_SEARCH_CHARS = { CSV_DELIMITER, CSV_QUOTE, CharUtils.CR, CharUtils.LF };
055
056        @Override
057        public int translate(final CharSequence input, final int index, final Writer out) throws IOException {
058            if (index != 0) {
059                throw new IllegalStateException("CsvEscaper should never reach the [1] index");
060            }
061            if (StringUtils.containsNone(input.toString(), CSV_SEARCH_CHARS)) {
062                out.write(input.toString());
063            } else {
064                out.write(CSV_QUOTE);
065                out.write(Strings.CS.replace(input.toString(), CSV_QUOTE_STR, CSV_QUOTE_STR + CSV_QUOTE_STR));
066                out.write(CSV_QUOTE);
067            }
068            return Character.codePointCount(input, 0, input.length());
069        }
070    }
071
072    private static final class CsvUnescaper extends CharSequenceTranslator {
073
074        private static final char CSV_DELIMITER = ',';
075        private static final char CSV_QUOTE = '"';
076        private static final String CSV_QUOTE_STR = String.valueOf(CSV_QUOTE);
077        private static final char[] CSV_SEARCH_CHARS = {CSV_DELIMITER, CSV_QUOTE, CharUtils.CR, CharUtils.LF};
078
079        @Override
080        public int translate(final CharSequence input, final int index, final Writer out) throws IOException {
081            if (index != 0) {
082                throw new IllegalStateException("CsvUnescaper should never reach the [1] index");
083            }
084            if (input.charAt(0) != CSV_QUOTE || input.charAt(input.length() - 1) != CSV_QUOTE) {
085                out.write(input.toString());
086                return Character.codePointCount(input, 0, input.length());
087            }
088            // strip quotes
089            final String quoteless = input.subSequence(1, input.length() - 1).toString();
090            if (StringUtils.containsAny(quoteless, CSV_SEARCH_CHARS)) {
091                // deal with escaped quotes; ie) ""
092                out.write(Strings.CS.replace(quoteless, CSV_QUOTE_STR + CSV_QUOTE_STR, CSV_QUOTE_STR));
093            } else {
094                out.write(input.toString());
095            }
096            return Character.codePointCount(input, 0, input.length());
097        }
098    }
099
100    /**
101     * Translator object for escaping Java.
102     *
103     * While {@link #escapeJava(String)} is the expected method of use, this
104     * object allows the Java escaping functionality to be used
105     * as the foundation for a custom translator.
106     *
107     * @since 3.0
108     */
109    public static final CharSequenceTranslator ESCAPE_JAVA =
110          new LookupTranslator(
111            new String[][] {
112              {"\"", "\\\""},
113              {"\\", "\\\\"},
114          }).with(
115            new LookupTranslator(EntityArrays.JAVA_CTRL_CHARS_ESCAPE())
116          ).with(
117            JavaUnicodeEscaper.outsideOf(32, 0x7f)
118        );
119
120    /**
121     * Translator object for escaping EcmaScript/JavaScript.
122     *
123     * While {@link #escapeEcmaScript(String)} is the expected method of use, this
124     * object allows the EcmaScript escaping functionality to be used
125     * as the foundation for a custom translator.
126     *
127     * @since 3.0
128     */
129    public static final CharSequenceTranslator ESCAPE_ECMASCRIPT =
130        new AggregateTranslator(
131            new LookupTranslator(
132                      new String[][] {
133                            {"'", "\\'"},
134                            {"\"", "\\\""},
135                            {"\\", "\\\\"},
136                            {"/", "\\/"}
137                      }),
138            new LookupTranslator(EntityArrays.JAVA_CTRL_CHARS_ESCAPE()),
139            JavaUnicodeEscaper.outsideOf(32, 0x7f)
140        );
141
142    /**
143     * Translator object for escaping Json.
144     *
145     * While {@link #escapeJson(String)} is the expected method of use, this
146     * object allows the Json escaping functionality to be used
147     * as the foundation for a custom translator.
148     *
149     * @since 3.2
150     */
151    public static final CharSequenceTranslator ESCAPE_JSON =
152        new AggregateTranslator(
153            new LookupTranslator(
154                      new String[][] {
155                            {"\"", "\\\""},
156                            {"\\", "\\\\"},
157                            {"/", "\\/"}
158                      }),
159            new LookupTranslator(EntityArrays.JAVA_CTRL_CHARS_ESCAPE()),
160            JavaUnicodeEscaper.outsideOf(32, 0x7f)
161        );
162
163    /**
164     * Translator object for escaping XML.
165     *
166     * While {@link #escapeXml(String)} is the expected method of use, this
167     * object allows the XML escaping functionality to be used
168     * as the foundation for a custom translator.
169     *
170     * @since 3.0
171     * @deprecated Use {@link #ESCAPE_XML10} or {@link #ESCAPE_XML11} instead.
172     */
173    @Deprecated
174    public static final CharSequenceTranslator ESCAPE_XML =
175        new AggregateTranslator(
176            new LookupTranslator(EntityArrays.BASIC_ESCAPE()),
177            new LookupTranslator(EntityArrays.APOS_ESCAPE())
178        );
179
180    /**
181     * Translator object for escaping XML 1.0.
182     *
183     * While {@link #escapeXml10(String)} is the expected method of use, this
184     * object allows the XML escaping functionality to be used
185     * as the foundation for a custom translator.
186     *
187     * @since 3.3
188     */
189    public static final CharSequenceTranslator ESCAPE_XML10 =
190        new AggregateTranslator(
191            new LookupTranslator(EntityArrays.BASIC_ESCAPE()),
192            new LookupTranslator(EntityArrays.APOS_ESCAPE()),
193            new LookupTranslator(
194                    new String[][] {
195                            { "\u0000", StringUtils.EMPTY },
196                            { "\u0001", StringUtils.EMPTY },
197                            { "\u0002", StringUtils.EMPTY },
198                            { "\u0003", StringUtils.EMPTY },
199                            { "\u0004", StringUtils.EMPTY },
200                            { "\u0005", StringUtils.EMPTY },
201                            { "\u0006", StringUtils.EMPTY },
202                            { "\u0007", StringUtils.EMPTY },
203                            { "\u0008", StringUtils.EMPTY },
204                            { "\u000b", StringUtils.EMPTY },
205                            { "\u000c", StringUtils.EMPTY },
206                            { "\u000e", StringUtils.EMPTY },
207                            { "\u000f", StringUtils.EMPTY },
208                            { "\u0010", StringUtils.EMPTY },
209                            { "\u0011", StringUtils.EMPTY },
210                            { "\u0012", StringUtils.EMPTY },
211                            { "\u0013", StringUtils.EMPTY },
212                            { "\u0014", StringUtils.EMPTY },
213                            { "\u0015", StringUtils.EMPTY },
214                            { "\u0016", StringUtils.EMPTY },
215                            { "\u0017", StringUtils.EMPTY },
216                            { "\u0018", StringUtils.EMPTY },
217                            { "\u0019", StringUtils.EMPTY },
218                            { "\u001a", StringUtils.EMPTY },
219                            { "\u001b", StringUtils.EMPTY },
220                            { "\u001c", StringUtils.EMPTY },
221                            { "\u001d", StringUtils.EMPTY },
222                            { "\u001e", StringUtils.EMPTY },
223                            { "\u001f", StringUtils.EMPTY },
224                            { "\ufffe", StringUtils.EMPTY },
225                            { "\uffff", StringUtils.EMPTY }
226                    }),
227            NumericEntityEscaper.between(0x7f, 0x84),
228            NumericEntityEscaper.between(0x86, 0x9f),
229            new UnicodeUnpairedSurrogateRemover()
230        );
231
232    /**
233     * Translator object for escaping XML 1.1.
234     *
235     * While {@link #escapeXml11(String)} is the expected method of use, this
236     * object allows the XML escaping functionality to be used
237     * as the foundation for a custom translator.
238     *
239     * @since 3.3
240     */
241    public static final CharSequenceTranslator ESCAPE_XML11 =
242        new AggregateTranslator(
243            new LookupTranslator(EntityArrays.BASIC_ESCAPE()),
244            new LookupTranslator(EntityArrays.APOS_ESCAPE()),
245            new LookupTranslator(
246                    new String[][] {
247                            { "\u0000", StringUtils.EMPTY },
248                            { "\u000b", "&#11;" },
249                            { "\u000c", "&#12;" },
250                            { "\ufffe", StringUtils.EMPTY },
251                            { "\uffff", StringUtils.EMPTY }
252                    }),
253            NumericEntityEscaper.between(0x1, 0x8),
254            NumericEntityEscaper.between(0xe, 0x1f),
255            NumericEntityEscaper.between(0x7f, 0x84),
256            NumericEntityEscaper.between(0x86, 0x9f),
257            new UnicodeUnpairedSurrogateRemover()
258        );
259
260    /**
261     * Translator object for escaping HTML version 3.0.
262     *
263     * While {@link #escapeHtml3(String)} is the expected method of use, this
264     * object allows the HTML escaping functionality to be used
265     * as the foundation for a custom translator.
266     *
267     * @since 3.0
268     */
269    public static final CharSequenceTranslator ESCAPE_HTML3 =
270        new AggregateTranslator(
271            new LookupTranslator(EntityArrays.BASIC_ESCAPE()),
272            new LookupTranslator(EntityArrays.ISO8859_1_ESCAPE())
273        );
274
275    /**
276     * Translator object for escaping HTML version 4.0.
277     *
278     * While {@link #escapeHtml4(String)} is the expected method of use, this
279     * object allows the HTML escaping functionality to be used
280     * as the foundation for a custom translator.
281     *
282     * @since 3.0
283     */
284    public static final CharSequenceTranslator ESCAPE_HTML4 =
285        new AggregateTranslator(
286            new LookupTranslator(EntityArrays.BASIC_ESCAPE()),
287            new LookupTranslator(EntityArrays.ISO8859_1_ESCAPE()),
288            new LookupTranslator(EntityArrays.HTML40_EXTENDED_ESCAPE())
289        );
290
291    /* UNESCAPE TRANSLATORS */
292
293    /**
294     * Translator object for escaping individual Comma Separated Values.
295     *
296     * While {@link #escapeCsv(String)} is the expected method of use, this
297     * object allows the CSV escaping functionality to be used
298     * as the foundation for a custom translator.
299     *
300     * @since 3.0
301     */
302    public static final CharSequenceTranslator ESCAPE_CSV = new CsvEscaper();
303
304    /**
305     * Translator object for unescaping escaped Java.
306     *
307     * While {@link #unescapeJava(String)} is the expected method of use, this
308     * object allows the Java unescaping functionality to be used
309     * as the foundation for a custom translator.
310     *
311     * @since 3.0
312     */
313    // TODO: throw "illegal character: \92" as an Exception if a \ on the end of the Java (as per the compiler)?
314    public static final CharSequenceTranslator UNESCAPE_JAVA =
315        new AggregateTranslator(
316            new OctalUnescaper(),     // .between('\1', '\377'),
317            new UnicodeUnescaper(),
318            new LookupTranslator(EntityArrays.JAVA_CTRL_CHARS_UNESCAPE()),
319            new LookupTranslator(
320                      new String[][] {
321                            {"\\\\", "\\"},
322                            {"\\\"", "\""},
323                            {"\\'", "'"},
324                            {"\\", ""}
325                      })
326        );
327
328    /**
329     * Translator object for unescaping escaped EcmaScript.
330     *
331     * While {@link #unescapeEcmaScript(String)} is the expected method of use, this
332     * object allows the EcmaScript unescaping functionality to be used
333     * as the foundation for a custom translator.
334     *
335     * @since 3.0
336     */
337    public static final CharSequenceTranslator UNESCAPE_ECMASCRIPT = UNESCAPE_JAVA;
338
339    /**
340     * Translator object for unescaping escaped Json.
341     *
342     * While {@link #unescapeJson(String)} is the expected method of use, this
343     * object allows the Json unescaping functionality to be used
344     * as the foundation for a custom translator.
345     *
346     * @since 3.2
347     */
348    public static final CharSequenceTranslator UNESCAPE_JSON = UNESCAPE_JAVA;
349
350    /**
351     * Translator object for unescaping escaped HTML 3.0.
352     *
353     * While {@link #unescapeHtml3(String)} is the expected method of use, this
354     * object allows the HTML unescaping functionality to be used
355     * as the foundation for a custom translator.
356     *
357     * @since 3.0
358     */
359    public static final CharSequenceTranslator UNESCAPE_HTML3 =
360        new AggregateTranslator(
361            new LookupTranslator(EntityArrays.BASIC_UNESCAPE()),
362            new LookupTranslator(EntityArrays.ISO8859_1_UNESCAPE()),
363            new NumericEntityUnescaper()
364        );
365
366    /**
367     * Translator object for unescaping escaped HTML 4.0.
368     *
369     * While {@link #unescapeHtml4(String)} is the expected method of use, this
370     * object allows the HTML unescaping functionality to be used
371     * as the foundation for a custom translator.
372     *
373     * @since 3.0
374     */
375    public static final CharSequenceTranslator UNESCAPE_HTML4 =
376        new AggregateTranslator(
377            new LookupTranslator(EntityArrays.BASIC_UNESCAPE()),
378            new LookupTranslator(EntityArrays.ISO8859_1_UNESCAPE()),
379            new LookupTranslator(EntityArrays.HTML40_EXTENDED_UNESCAPE()),
380            new NumericEntityUnescaper()
381        );
382
383    /**
384     * Translator object for unescaping escaped XML.
385     *
386     * While {@link #unescapeXml(String)} is the expected method of use, this
387     * object allows the XML unescaping functionality to be used
388     * as the foundation for a custom translator.
389     *
390     * @since 3.0
391     */
392    public static final CharSequenceTranslator UNESCAPE_XML =
393        new AggregateTranslator(
394            new LookupTranslator(EntityArrays.BASIC_UNESCAPE()),
395            new LookupTranslator(EntityArrays.APOS_UNESCAPE()),
396            new NumericEntityUnescaper()
397        );
398
399    /**
400     * Translator object for unescaping escaped Comma Separated Value entries.
401     *
402     * While {@link #unescapeCsv(String)} is the expected method of use, this
403     * object allows the CSV unescaping functionality to be used
404     * as the foundation for a custom translator.
405     *
406     * @since 3.0
407     */
408    public static final CharSequenceTranslator UNESCAPE_CSV = new CsvUnescaper();
409
410    /* Helper functions */
411
412    /**
413     * Returns a {@link String} value for a CSV column enclosed in double quotes,
414     * if required.
415     *
416     * <p>If the value contains a comma, newline or double quote, then the
417     *    String value is returned enclosed in double quotes.</p>
418     *
419     * <p>Any double quote characters in the value are escaped with another double quote.</p>
420     *
421     * <p>If the value does not contain a comma, newline or double quote, then the
422     *    String value is returned unchanged.</p>
423     *
424     * see <a href="https://en.wikipedia.org/wiki/Comma-separated_values">Wikipedia</a> and
425     * <a href="https://datatracker.ietf.org/doc/html/rfc4180">RFC 4180</a>.
426     *
427     * @param input the input CSV column String, may be null
428     * @return the input String, enclosed in double quotes if the value contains a comma,
429     * newline or double quote, {@code null} if null string input
430     * @since 2.4
431     */
432    public static final String escapeCsv(final String input) {
433        return ESCAPE_CSV.translate(input);
434    }
435
436    /**
437     * Escapes the characters in a {@link String} using EcmaScript String rules.
438     * <p>Escapes any values it finds into their EcmaScript String form.
439     * Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.) </p>
440     *
441     * <p>So a tab becomes the characters {@code '\\'} and
442     * {@code 't'}.</p>
443     *
444     * <p>The only difference between Java strings and EcmaScript strings
445     * is that in EcmaScript, a single quote and forward-slash (/) are escaped.</p>
446     *
447     * <p>Note that EcmaScript is best known by the JavaScript and ActionScript dialects.</p>
448     *
449     * <p>Example:</p>
450     * <pre>
451     * input string: He didn't say, "Stop!"
452     * output string: He didn\'t say, \"Stop!\"
453     * </pre>
454     *
455     * @param input  String to escape values in, may be null
456     * @return String with escaped values, {@code null} if null string input
457     * @since 3.0
458     */
459    public static final String escapeEcmaScript(final String input) {
460        return ESCAPE_ECMASCRIPT.translate(input);
461    }
462
463    /**
464     * Escapes the characters in a {@link String} using HTML entities.
465     * <p>Supports only the HTML 3.0 entities.</p>
466     *
467     * @param input  the {@link String} to escape, may be null
468     * @return a new escaped {@link String}, {@code null} if null string input
469     * @since 3.0
470     */
471    public static final String escapeHtml3(final String input) {
472        return ESCAPE_HTML3.translate(input);
473    }
474
475    /**
476     * Escapes the characters in a {@link String} using HTML entities.
477     *
478     * <p>
479     * For example:
480     * </p>
481     * <p>{@code "bread" &amp; "butter"}</p>
482     * becomes:
483     * <p>
484     * {@code &amp;quot;bread&amp;quot; &amp;amp; &amp;quot;butter&amp;quot;}.
485     * </p>
486     *
487     * <p>Supports all known HTML 4.0 entities, including funky accents.
488     * Note that the commonly used apostrophe escape character (&amp;apos;)
489     * is not a legal entity and so is not supported).</p>
490     *
491     * @param input  the {@link String} to escape, may be null
492     * @return a new escaped {@link String}, {@code null} if null string input
493     * @see <a href="https://web.archive.org/web/20060225074150/https://hotwired.lycos.com/webmonkey/reference/special_characters/">ISO Entities</a>
494     * @see <a href="https://www.w3.org/TR/REC-html32#latin1">HTML 3.2 Character Entities for ISO Latin-1</a>
495     * @see <a href="https://www.w3.org/TR/REC-html40/sgml/entities.html">HTML 4.0 Character entity references</a>
496     * @see <a href="https://www.w3.org/TR/html401/charset.html#h-5.3">HTML 4.01 Character References</a>
497     * @see <a href="https://www.w3.org/TR/html401/charset.html#code-position">HTML 4.01 Code positions</a>
498     * @since 3.0
499     */
500    public static final String escapeHtml4(final String input) {
501        return ESCAPE_HTML4.translate(input);
502    }
503
504    /**
505     * Escapes the characters in a {@link String} using Java String rules.
506     *
507     * <p>Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.) </p>
508     *
509     * <p>So a tab becomes the characters {@code '\\'} and
510     * {@code 't'}.</p>
511     *
512     * <p>The only difference between Java strings and JavaScript strings
513     * is that in JavaScript, a single quote and forward-slash (/) are escaped.</p>
514     *
515     * <p>Example:</p>
516     * <pre>
517     * input string: He didn't say, "Stop!"
518     * output string: He didn't say, \"Stop!\"
519     * </pre>
520     *
521     * @param input  String to escape values in, may be null
522     * @return String with escaped values, {@code null} if null string input
523     */
524    public static final String escapeJava(final String input) {
525        return ESCAPE_JAVA.translate(input);
526    }
527
528    /**
529     * Escapes the characters in a {@link String} using Json String rules.
530     * <p>Escapes any values it finds into their Json String form.
531     * Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.) </p>
532     *
533     * <p>So a tab becomes the characters {@code '\\'} and
534     * {@code 't'}.</p>
535     *
536     * <p>The only difference between Java strings and Json strings
537     * is that in Json, forward-slash (/) is escaped.</p>
538     *
539     * <p>See https://www.ietf.org/rfc/rfc4627.txt for further details.</p>
540     *
541     * <p>Example:</p>
542     * <pre>
543     * input string: He didn't say, "Stop!"
544     * output string: He didn't say, \"Stop!\"
545     * </pre>
546     *
547     * @param input  String to escape values in, may be null
548     * @return String with escaped values, {@code null} if null string input
549     * @since 3.2
550     */
551    public static final String escapeJson(final String input) {
552        return ESCAPE_JSON.translate(input);
553    }
554
555    /**
556     * Escapes the characters in a {@link String} using XML entities.
557     *
558     * <p>For example: {@code "bread" & "butter"} =&gt;
559     * {@code &quot;bread&quot; &amp; &quot;butter&quot;}.
560     * </p>
561     *
562     * <p>Supports only the five basic XML entities (gt, lt, quot, amp, apos).
563     * Does not support DTDs or external entities.</p>
564     *
565     * <p>Note that Unicode characters greater than 0x7f are as of 3.0, no longer
566     *    escaped. If you still wish this functionality, you can achieve it
567     *    via the following:
568     * {@code StringEscapeUtils.ESCAPE_XML.with( NumericEntityEscaper.between(0x7f, Integer.MAX_VALUE));}</p>
569     *
570     * @param input  the {@link String} to escape, may be null
571     * @return a new escaped {@link String}, {@code null} if null string input
572     * @see #unescapeXml(String)
573     * @deprecated Use {@link #escapeXml10(java.lang.String)} or {@link #escapeXml11(java.lang.String)} instead.
574     */
575    @Deprecated
576    public static final String escapeXml(final String input) {
577        return ESCAPE_XML.translate(input);
578    }
579
580    /**
581     * Escapes the characters in a {@link String} using XML entities.
582     * <p>
583     * For example:
584     * </p>
585     *
586     * <pre>{@code
587     * "bread" & "butter"
588     * }</pre>
589     * <p>
590     * converts to:
591     * </p>
592     *
593     * <pre>
594     * {@code
595     * &quot;bread&quot; &amp; &quot;butter&quot;
596     * }
597     * </pre>
598     *
599     * <p>
600     * Note that XML 1.0 is a text-only format: it cannot represent control characters or unpaired Unicode surrogate code points, even after escaping. The
601     * method {@code escapeXml10} will remove characters that do not fit in the following ranges:
602     * </p>
603     *
604     * <p>
605     * {@code #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]}
606     * </p>
607     *
608     * <p>
609     * Though not strictly necessary, {@code escapeXml10} will escape characters in the following ranges:
610     * </p>
611     *
612     * <p>
613     * {@code [#x7F-#x84] | [#x86-#x9F]}
614     * </p>
615     *
616     * <p>
617     * The returned string can be inserted into a valid XML 1.0 or XML 1.1 document. If you want to allow more non-text characters in an XML 1.1 document, use
618     * {@link #escapeXml11(String)}.
619     * </p>
620     *
621     * @param input the {@link String} to escape, may be null
622     * @return a new escaped {@link String}, {@code null} if null string input
623     * @see #unescapeXml(String)
624     * @since 3.3
625     */
626    public static String escapeXml10(final String input) {
627        return ESCAPE_XML10.translate(input);
628    }
629
630    /**
631     * Escapes the characters in a {@link String} using XML entities.
632     *
633     * <p>For example: {@code "bread" & "butter"} =&gt;
634     * {@code &quot;bread&quot; &amp; &quot;butter&quot;}.
635     * </p>
636     *
637     * <p>XML 1.1 can represent certain control characters, but it cannot represent
638     * the null byte or unpaired Unicode surrogate code points, even after escaping.
639     * {@code escapeXml11} will remove characters that do not fit in the following
640     * ranges:</p>
641     *
642     * <p>{@code [#x1-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]}</p>
643     *
644     * <p>{@code escapeXml11} will escape characters in the following ranges:</p>
645     *
646     * <p>{@code [#x1-#x8] | [#xB-#xC] | [#xE-#x1F] | [#x7F-#x84] | [#x86-#x9F]}</p>
647     *
648     * <p>The returned string can be inserted into a valid XML 1.1 document. Do not
649     * use it for XML 1.0 documents.</p>
650     *
651     * @param input  the {@link String} to escape, may be null
652     * @return a new escaped {@link String}, {@code null} if null string input
653     * @see #unescapeXml(String)
654     * @since 3.3
655     */
656    public static String escapeXml11(final String input) {
657        return ESCAPE_XML11.translate(input);
658    }
659
660    /**
661     * Returns a {@link String} value for an unescaped CSV column.
662     *
663     * <p>If the value is enclosed in double quotes, and contains a comma, newline
664     *    or double quote, then quotes are removed.
665     * </p>
666     *
667     * <p>Any double quote escaped characters (a pair of double quotes) are unescaped
668     *    to just one double quote.</p>
669     *
670     * <p>If the value is not enclosed in double quotes, or is and does not contain a
671     *    comma, newline or double quote, then the String value is returned unchanged.</p>
672     *
673     * see <a href="https://en.wikipedia.org/wiki/Comma-separated_values">Wikipedia</a> and
674     * <a href="https://datatracker.ietf.org/doc/html/rfc4180">RFC 4180</a>.
675     *
676     * @param input the input CSV column String, may be null
677     * @return the input String, with enclosing double quotes removed and embedded double
678     * quotes unescaped, {@code null} if null string input
679     * @since 2.4
680     */
681    public static final String unescapeCsv(final String input) {
682        return UNESCAPE_CSV.translate(input);
683    }
684
685    /**
686     * Unescapes any EcmaScript literals found in the {@link String}.
687     *
688     * <p>For example, it will turn a sequence of {@code '\'} and {@code 'n'}
689     * into a newline character, unless the {@code '\'} is preceded by another
690     * {@code '\'}.</p>
691     *
692     * @see #unescapeJava(String)
693     * @param input  the {@link String} to unescape, may be null
694     * @return A new unescaped {@link String}, {@code null} if null string input
695     * @since 3.0
696     */
697    public static final String unescapeEcmaScript(final String input) {
698        return UNESCAPE_ECMASCRIPT.translate(input);
699    }
700
701    /**
702     * Unescapes a string containing entity escapes to a string
703     * containing the actual Unicode characters corresponding to the
704     * escapes. Supports only HTML 3.0 entities.
705     *
706     * @param input  the {@link String} to unescape, may be null
707     * @return a new unescaped {@link String}, {@code null} if null string input
708     * @since 3.0
709     */
710    public static final String unescapeHtml3(final String input) {
711        return UNESCAPE_HTML3.translate(input);
712    }
713
714    /**
715     * Unescapes a string containing entity escapes to a string
716     * containing the actual Unicode characters corresponding to the
717     * escapes. Supports HTML 4.0 entities.
718     *
719     * <p>For example, the string {@code "&lt;Fran&ccedil;ais&gt;"}
720     * will become {@code "<Français>"}</p>
721     *
722     * <p>If an entity is unrecognized, it is left alone, and inserted
723     * verbatim into the result string. e.g. {@code "&gt;&zzzz;x"} will
724     * become {@code ">&zzzz;x"}.</p>
725     *
726     * @param input  the {@link String} to unescape, may be null
727     * @return a new unescaped {@link String}, {@code null} if null string input
728     * @since 3.0
729     */
730    public static final String unescapeHtml4(final String input) {
731        return UNESCAPE_HTML4.translate(input);
732    }
733
734    /**
735     * Unescapes any Java literals found in the {@link String}.
736     * For example, it will turn a sequence of {@code '\'} and
737     * {@code 'n'} into a newline character, unless the {@code '\'}
738     * is preceded by another {@code '\'}.
739     *
740     * @param input  the {@link String} to unescape, may be null
741     * @return a new unescaped {@link String}, {@code null} if null string input
742     */
743    public static final String unescapeJava(final String input) {
744        return UNESCAPE_JAVA.translate(input);
745    }
746
747    /**
748     * Unescapes any Json literals found in the {@link String}.
749     *
750     * <p>For example, it will turn a sequence of {@code '\'} and {@code 'n'}
751     * into a newline character, unless the {@code '\'} is preceded by another
752     * {@code '\'}.</p>
753     *
754     * @see #unescapeJava(String)
755     * @param input  the {@link String} to unescape, may be null
756     * @return A new unescaped {@link String}, {@code null} if null string input
757     * @since 3.2
758     */
759    public static final String unescapeJson(final String input) {
760        return UNESCAPE_JSON.translate(input);
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     * @deprecated TODO Make private in 4.0.
795     */
796    @Deprecated
797    public StringEscapeUtils() {
798        // empty
799    }
800
801}