1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.text;
18
19 import java.util.ArrayList;
20 import java.util.List;
21 import java.util.Map;
22 import java.util.Properties;
23 import java.util.function.Function;
24 import java.util.stream.Collectors;
25
26 import org.apache.commons.lang3.Validate;
27
28 /**
29 * Substitutes variables within a string by values.
30 * <p>
31 * This class takes a piece of text and substitutes all the variables within it.
32 * The default definition of a variable is {@code ${variableName}}.
33 * The prefix and suffix can be changed via constructors and set methods.
34 * <p>
35 * Variable values are typically resolved from a map, but could also be resolved
36 * from system properties, or by supplying a custom variable resolver.
37 * <p>
38 * The simplest example is to use this class to replace Java System properties. For example:
39 * <pre>
40 * StrSubstitutor.replaceSystemProperties(
41 * "You are running with java.version = ${java.version} and os.name = ${os.name}.");
42 * </pre>
43 * <p>
44 * Typical usage of this class follows the following pattern: First an instance is created
45 * and initialized with the map that contains the values for the available variables.
46 * If a prefix and/or suffix for variables should be used other than the default ones,
47 * the appropriate settings can be performed. After that the {@code replace()}
48 * method can be called passing in the source text for interpolation. In the returned
49 * text all variable references (as long as their values are known) will be resolved.
50 * The following example demonstrates this:
51 * <pre>
52 * Map<String, String> valuesMap = new HashMap<>();
53 * valuesMap.put("animal", "quick brown fox");
54 * valuesMap.put("target", "lazy dog");
55 * String templateString = "The ${animal} jumped over the ${target}.";
56 * StrSubstitutor sub = new StrSubstitutor(valuesMap);
57 * String resolvedString = sub.replace(templateString);
58 * </pre>
59 * yielding:
60 * <pre>
61 * The quick brown fox jumped over the lazy dog.
62 * </pre>
63 * <p>
64 * Also, this class allows to set a default value for unresolved variables.
65 * The default value for a variable can be appended to the variable name after the variable
66 * default value delimiter. The default value of the variable default value delimiter is ':-',
67 * as in bash and other *nix shells, as those are arguably where the default ${} delimiter set originated.
68 * The variable default value delimiter can be manually set by calling {@link #setValueDelimiterMatcher(StrMatcher)},
69 * {@link #setValueDelimiter(char)} or {@link #setValueDelimiter(String)}.
70 * The following shows an example with variable default value settings:
71 * <pre>
72 * Map<String, String> valuesMap = new HashMap<>();
73 * valuesMap.put("animal", "quick brown fox");
74 * valuesMap.put("target", "lazy dog");
75 * String templateString = "The ${animal} jumped over the ${target}. ${undefined.number:-1234567890}.";
76 * StrSubstitutor sub = new StrSubstitutor(valuesMap);
77 * String resolvedString = sub.replace(templateString);
78 * </pre>
79 * yielding:
80 * <pre>
81 * The quick brown fox jumped over the lazy dog. 1234567890.
82 * </pre>
83 * <p>
84 * In addition to this usage pattern there are some static convenience methods that
85 * cover the most common use cases. These methods can be used without the need of
86 * manually creating an instance. However if multiple replace operations are to be
87 * performed, creating and reusing an instance of this class will be more efficient.
88 * <p>
89 * Variable replacement works in a recursive way. Thus, if a variable value contains
90 * a variable then that variable will also be replaced. Cyclic replacements are
91 * detected and will cause an exception to be thrown.
92 * <p>
93 * Sometimes the interpolation's result must contain a variable prefix. As an example
94 * take the following source text:
95 * <pre>
96 * The variable ${${name}} must be used.
97 * </pre>
98 * Here only the variable's name referred to in the text should be replaced resulting
99 * in the text (assuming that the value of the {@code name} variable is {@code x}):
100 * <pre>
101 * The variable ${x} must be used.
102 * </pre>
103 * To achieve this effect there are two possibilities: Either set a different prefix
104 * and suffix for variables which do not conflict with the result text you want to
105 * produce. The other possibility is to use the escape character, by default '$'.
106 * If this character is placed before a variable reference, this reference is ignored
107 * and won't be replaced. For example:
108 * <pre>
109 * The variable $${${name}} must be used.
110 * </pre>
111 * <p>
112 * In some complex scenarios you might even want to perform substitution in the
113 * names of variables, for instance
114 * <pre>
115 * ${jre-${java.specification.version}}
116 * </pre>
117 * {@code StrSubstitutor} supports this recursive substitution in variable
118 * names, but it has to be enabled explicitly by setting the
119 * {@link #setEnableSubstitutionInVariables(boolean) enableSubstitutionInVariables}
120 * property to <b>true</b>.
121 * <p>This class is <b>not</b> thread safe.</p>
122 *
123 * @since 1.0
124 * @deprecated Deprecated as of 1.3, use {@link StringSubstitutor} instead. This class will be removed in 2.0.
125 */
126 @Deprecated
127 public class StrSubstitutor {
128
129 /**
130 * Constant for the default escape character.
131 */
132 public static final char DEFAULT_ESCAPE = '$';
133
134 /**
135 * Constant for the default variable prefix.
136 */
137 public static final StrMatcher DEFAULT_PREFIX = StrMatcher.stringMatcher("${");
138
139 /**
140 * Constant for the default variable suffix.
141 */
142 public static final StrMatcher DEFAULT_SUFFIX = StrMatcher.stringMatcher("}");
143
144 /**
145 * Constant for the default value delimiter of a variable.
146 */
147 public static final StrMatcher DEFAULT_VALUE_DELIMITER = StrMatcher.stringMatcher(":-");
148
149 /**
150 * Replaces all the occurrences of variables in the given source object with
151 * their matching values from the map.
152 *
153 * @param <V> the type of the values in the map
154 * @param source the source text containing the variables to substitute, null returns null
155 * @param valueMap the map with the values, may be null
156 * @return The result of the replace operation
157 */
158 public static <V> String replace(final Object source, final Map<String, V> valueMap) {
159 return new StrSubstitutor(valueMap).replace(source);
160 }
161
162 /**
163 * Replaces all the occurrences of variables in the given source object with
164 * their matching values from the map. This method allows to specify a
165 * custom variable prefix and suffix
166 *
167 * @param <V> the type of the values in the map
168 * @param source the source text containing the variables to substitute, null returns null
169 * @param valueMap the map with the values, may be null
170 * @param prefix the prefix of variables, not null
171 * @param suffix the suffix of variables, not null
172 * @return The result of the replace operation
173 * @throws IllegalArgumentException if the prefix or suffix is null
174 */
175 public static <V> String replace(final Object source,
176 final Map<String, V> valueMap,
177 final String prefix,
178 final String suffix) {
179 return new StrSubstitutor(valueMap, prefix, suffix).replace(source);
180 }
181
182 /**
183 * Replaces all the occurrences of variables in the given source object with their matching
184 * values from the properties.
185 *
186 * @param source the source text containing the variables to substitute, null returns null
187 * @param valueProperties the properties with values, may be null
188 * @return The result of the replace operation
189 */
190 public static String replace(final Object source, final Properties valueProperties) {
191 if (valueProperties == null) {
192 return source.toString();
193 }
194 return StrSubstitutor.replace(source,
195 valueProperties.stringPropertyNames().stream().collect(Collectors.toMap(Function.identity(), valueProperties::getProperty)));
196 }
197
198 /**
199 * Replaces all the occurrences of variables in the given source object with
200 * their matching values from the system properties.
201 *
202 * @param source the source text containing the variables to substitute, null returns null
203 * @return The result of the replace operation
204 */
205 public static String replaceSystemProperties(final Object source) {
206 return new StrSubstitutor(StrLookup.systemPropertiesLookup()).replace(source);
207 }
208
209 /**
210 * Stores the escape character.
211 */
212 private char escapeChar;
213
214 /**
215 * Stores the variable prefix.
216 */
217 private StrMatcher prefixMatcher;
218
219 /**
220 * Stores the variable suffix.
221 */
222 private StrMatcher suffixMatcher;
223
224 /**
225 * Stores the default variable value delimiter.
226 */
227 private StrMatcher valueDelimiterMatcher;
228
229 /**
230 * Variable resolution is delegated to an implementor of VariableResolver.
231 */
232 private StrLookup<?> variableResolver;
233
234 /**
235 * The flag whether substitution in variable names is enabled.
236 */
237 private boolean enableSubstitutionInVariables;
238
239 /**
240 * Whether escapes should be preserved. Default is false;
241 */
242 private boolean preserveEscapes;
243
244 /**
245 * The flag whether substitution in variable values is disabled.
246 */
247 private boolean disableSubstitutionInValues;
248
249 /**
250 * Constructs a new instance with defaults for variable prefix and suffix
251 * and the escaping character.
252 */
253 public StrSubstitutor() {
254 this((StrLookup<?>) null, DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE);
255 }
256
257 /**
258 * Constructs a new instance and initializes it. Uses defaults for variable
259 * prefix and suffix and the escaping character.
260 *
261 * @param <V> the type of the values in the map
262 * @param valueMap the map with the variables' values, may be null
263 */
264 public <V> StrSubstitutor(final Map<String, V> valueMap) {
265 this(StrLookup.mapLookup(valueMap), DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE);
266 }
267
268 /**
269 * Constructs a new instance and initializes it. Uses a default escaping character.
270 *
271 * @param <V> the type of the values in the map
272 * @param valueMap the map with the variables' values, may be null
273 * @param prefix the prefix for variables, not null
274 * @param suffix the suffix for variables, not null
275 * @throws IllegalArgumentException if the prefix or suffix is null
276 */
277 public <V> StrSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix) {
278 this(StrLookup.mapLookup(valueMap), prefix, suffix, DEFAULT_ESCAPE);
279 }
280
281 /**
282 * Constructs a new instance and initializes it.
283 *
284 * @param <V> the type of the values in the map
285 * @param valueMap the map with the variables' values, may be null
286 * @param prefix the prefix for variables, not null
287 * @param suffix the suffix for variables, not null
288 * @param escape the escape character
289 * @throws IllegalArgumentException if the prefix or suffix is null
290 */
291 public <V> StrSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix,
292 final char escape) {
293 this(StrLookup.mapLookup(valueMap), prefix, suffix, escape);
294 }
295
296 /**
297 * Constructs a new instance and initializes it.
298 *
299 * @param <V> the type of the values in the map
300 * @param valueMap the map with the variables' values, may be null
301 * @param prefix the prefix for variables, not null
302 * @param suffix the suffix for variables, not null
303 * @param escape the escape character
304 * @param valueDelimiter the variable default value delimiter, may be null
305 * @throws IllegalArgumentException if the prefix or suffix is null
306 */
307 public <V> StrSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix,
308 final char escape, final String valueDelimiter) {
309 this(StrLookup.mapLookup(valueMap), prefix, suffix, escape, valueDelimiter);
310 }
311
312 /**
313 * Constructs a new instance and initializes it.
314 *
315 * @param variableResolver the variable resolver, may be null
316 */
317 public StrSubstitutor(final StrLookup<?> variableResolver) {
318 this(variableResolver, DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE);
319 }
320
321 /**
322 * Constructs a new instance and initializes it.
323 *
324 * @param variableResolver the variable resolver, may be null
325 * @param prefix the prefix for variables, not null
326 * @param suffix the suffix for variables, not null
327 * @param escape the escape character
328 * @throws IllegalArgumentException if the prefix or suffix is null
329 */
330 public StrSubstitutor(final StrLookup<?> variableResolver, final String prefix, final String suffix,
331 final char escape) {
332 this.setVariableResolver(variableResolver);
333 this.setVariablePrefix(prefix);
334 this.setVariableSuffix(suffix);
335 this.setEscapeChar(escape);
336 this.setValueDelimiterMatcher(DEFAULT_VALUE_DELIMITER);
337 }
338
339 /**
340 * Constructs a new instance and initializes it.
341 *
342 * @param variableResolver the variable resolver, may be null
343 * @param prefix the prefix for variables, not null
344 * @param suffix the suffix for variables, not null
345 * @param escape the escape character
346 * @param valueDelimiter the variable default value delimiter string, may be null
347 * @throws IllegalArgumentException if the prefix or suffix is null
348 */
349 public StrSubstitutor(final StrLookup<?> variableResolver, final String prefix, final String suffix,
350 final char escape, final String valueDelimiter) {
351 this.setVariableResolver(variableResolver);
352 this.setVariablePrefix(prefix);
353 this.setVariableSuffix(suffix);
354 this.setEscapeChar(escape);
355 this.setValueDelimiter(valueDelimiter);
356 }
357
358 /**
359 * Constructs a new instance and initializes it.
360 *
361 * @param variableResolver the variable resolver, may be null
362 * @param prefixMatcher the prefix for variables, not null
363 * @param suffixMatcher the suffix for variables, not null
364 * @param escape the escape character
365 * @throws IllegalArgumentException if the prefix or suffix is null
366 */
367 public StrSubstitutor(
368 final StrLookup<?> variableResolver, final StrMatcher prefixMatcher, final StrMatcher suffixMatcher,
369 final char escape) {
370 this(variableResolver, prefixMatcher, suffixMatcher, escape, DEFAULT_VALUE_DELIMITER);
371 }
372
373 /**
374 * Constructs a new instance and initializes it.
375 *
376 * @param variableResolver the variable resolver, may be null
377 * @param prefixMatcher the prefix for variables, not null
378 * @param suffixMatcher the suffix for variables, not null
379 * @param escape the escape character
380 * @param valueDelimiterMatcher the variable default value delimiter matcher, may be null
381 * @throws IllegalArgumentException if the prefix or suffix is null
382 */
383 public StrSubstitutor(
384 final StrLookup<?> variableResolver, final StrMatcher prefixMatcher, final StrMatcher suffixMatcher,
385 final char escape, final StrMatcher valueDelimiterMatcher) {
386 this.setVariableResolver(variableResolver);
387 this.setVariablePrefixMatcher(prefixMatcher);
388 this.setVariableSuffixMatcher(suffixMatcher);
389 this.setEscapeChar(escape);
390 this.setValueDelimiterMatcher(valueDelimiterMatcher);
391 }
392
393 /**
394 * Checks if the specified variable is already in the stack (list) of variables.
395 *
396 * @param varName the variable name to check
397 * @param priorVariables the list of prior variables
398 */
399 private void checkCyclicSubstitution(final String varName, final List<String> priorVariables) {
400 if (!priorVariables.contains(varName)) {
401 return;
402 }
403 final StrBuilder buf = new StrBuilder(256);
404 buf.append("Infinite loop in property interpolation of ");
405 buf.append(priorVariables.remove(0));
406 buf.append(": ");
407 buf.appendWithSeparators(priorVariables, "->");
408 throw new IllegalStateException(buf.toString());
409 }
410
411 /**
412 * Returns the escape character.
413 *
414 * @return The character used for escaping variable references
415 */
416 public char getEscapeChar() {
417 return this.escapeChar;
418 }
419
420 /**
421 * Gets the variable default value delimiter matcher currently in use.
422 * <p>
423 * The variable default value delimiter is the character or characters that delimit the
424 * variable name and the variable default value. This delimiter is expressed in terms of a matcher
425 * allowing advanced variable default value delimiter matches.
426 * </p>
427 * <p>
428 * If it returns null, then the variable default value resolution is disabled.
429 * </p>
430 *
431 * @return The variable default value delimiter matcher in use, may be null
432 */
433 public StrMatcher getValueDelimiterMatcher() {
434 return valueDelimiterMatcher;
435 }
436
437 /**
438 * Gets the variable prefix matcher currently in use.
439 * <p>
440 * The variable prefix is the character or characters that identify the
441 * start of a variable. This prefix is expressed in terms of a matcher
442 * allowing advanced prefix matches.
443 * </p>
444 *
445 * @return The prefix matcher in use
446 */
447 public StrMatcher getVariablePrefixMatcher() {
448 return prefixMatcher;
449 }
450
451 /**
452 * Gets the VariableResolver that is used to lookup variables.
453 *
454 * @return The VariableResolver
455 */
456 public StrLookup<?> getVariableResolver() {
457 return this.variableResolver;
458 }
459
460 /**
461 * Gets the variable suffix matcher currently in use.
462 * <p>
463 * The variable suffix is the character or characters that identify the
464 * end of a variable. This suffix is expressed in terms of a matcher
465 * allowing advanced suffix matches.
466 * </p>
467 *
468 * @return The suffix matcher in use
469 */
470 public StrMatcher getVariableSuffixMatcher() {
471 return suffixMatcher;
472 }
473
474 /**
475 * Returns a flag whether substitution is disabled in variable values.If set to
476 * <b>true</b>, the values of variables can contain other variables will not be
477 * processed and substituted original variable is evaluated, e.g.
478 * <pre>
479 * Map<String, String> valuesMap = new HashMap<>();
480 * valuesMap.put("name", "Douglas ${surname}");
481 * valuesMap.put("surname", "Crockford");
482 * String templateString = "Hi ${name}";
483 * StrSubstitutor sub = new StrSubstitutor(valuesMap);
484 * String resolvedString = sub.replace(templateString);
485 * </pre>
486 * yielding:
487 * <pre>
488 * Hi Douglas ${surname}
489 * </pre>
490 *
491 * @return The substitution in variable values flag
492 *
493 * @since 1.2
494 */
495 public boolean isDisableSubstitutionInValues() {
496 return disableSubstitutionInValues;
497 }
498
499 /**
500 * Returns a flag whether substitution is done in variable names.
501 *
502 * @return The substitution in variable names flag
503 */
504 public boolean isEnableSubstitutionInVariables() {
505 return enableSubstitutionInVariables;
506 }
507
508 /**
509 * Returns the flag controlling whether escapes are preserved during
510 * substitution.
511 *
512 * @return The preserve escape flag
513 */
514 public boolean isPreserveEscapes() {
515 return preserveEscapes;
516 }
517
518 /**
519 * Replaces all the occurrences of variables with their matching values
520 * from the resolver using the given source array as a template.
521 * The array is not altered by this method.
522 *
523 * @param source the character array to replace in, not altered, null returns null
524 * @return The result of the replace operation
525 */
526 public String replace(final char[] source) {
527 if (source == null) {
528 return null;
529 }
530 final StrBuilder buf = new StrBuilder(source.length).append(source);
531 substitute(buf, 0, source.length);
532 return buf.toString();
533 }
534
535 /**
536 * Replaces all the occurrences of variables with their matching values
537 * from the resolver using the given source array as a template.
538 * The array is not altered by this method.
539 * <p>
540 * Only the specified portion of the array will be processed.
541 * The rest of the array is not processed, and is not returned.
542 * </p>
543 *
544 * @param source the character array to replace in, not altered, null returns null
545 * @param offset the start offset within the array, must be valid
546 * @param length the length within the array to be processed, must be valid
547 * @return The result of the replace operation
548 */
549 public String replace(final char[] source, final int offset, final int length) {
550 if (source == null) {
551 return null;
552 }
553 final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
554 substitute(buf, 0, length);
555 return buf.toString();
556 }
557
558 /**
559 * Replaces all the occurrences of variables with their matching values
560 * from the resolver using the given source as a template.
561 * The source is not altered by this method.
562 *
563 * @param source the buffer to use as a template, not changed, null returns null
564 * @return The result of the replace operation
565 */
566 public String replace(final CharSequence source) {
567 if (source == null) {
568 return null;
569 }
570 return replace(source, 0, source.length());
571 }
572
573 /**
574 * Replaces all the occurrences of variables with their matching values
575 * from the resolver using the given source as a template.
576 * The source is not altered by this method.
577 * <p>
578 * Only the specified portion of the buffer will be processed.
579 * The rest of the buffer is not processed, and is not returned.
580 * </p>
581 *
582 * @param source the buffer to use as a template, not changed, null returns null
583 * @param offset the start offset within the array, must be valid
584 * @param length the length within the array to be processed, must be valid
585 * @return The result of the replace operation
586 */
587 public String replace(final CharSequence source, final int offset, final int length) {
588 if (source == null) {
589 return null;
590 }
591 final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
592 substitute(buf, 0, length);
593 return buf.toString();
594 }
595
596 /**
597 * Replaces all the occurrences of variables in the given source object with
598 * their matching values from the resolver. The input source object is
599 * converted to a string using {@code toString} and is not altered.
600 *
601 * @param source the source to replace in, null returns null
602 * @return The result of the replace operation
603 */
604 public String replace(final Object source) {
605 if (source == null) {
606 return null;
607 }
608 final StrBuilder buf = new StrBuilder().append(source);
609 substitute(buf, 0, buf.length());
610 return buf.toString();
611 }
612
613 /**
614 * Replaces all the occurrences of variables with their matching values
615 * from the resolver using the given source builder as a template.
616 * The builder is not altered by this method.
617 *
618 * @param source the builder to use as a template, not changed, null returns null
619 * @return The result of the replace operation
620 */
621 public String replace(final StrBuilder source) {
622 if (source == null) {
623 return null;
624 }
625 final StrBuilder buf = new StrBuilder(source.length()).append(source);
626 substitute(buf, 0, buf.length());
627 return buf.toString();
628 }
629
630 /**
631 * Replaces all the occurrences of variables with their matching values
632 * from the resolver using the given source builder as a template.
633 * The builder is not altered by this method.
634 * <p>
635 * Only the specified portion of the builder will be processed.
636 * The rest of the builder is not processed, and is not returned.
637 * </p>
638 *
639 * @param source the builder to use as a template, not changed, null returns null
640 * @param offset the start offset within the array, must be valid
641 * @param length the length within the array to be processed, must be valid
642 * @return The result of the replace operation
643 */
644 public String replace(final StrBuilder source, final int offset, final int length) {
645 if (source == null) {
646 return null;
647 }
648 final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
649 substitute(buf, 0, length);
650 return buf.toString();
651 }
652
653 /**
654 * Replaces all the occurrences of variables with their matching values
655 * from the resolver using the given source string as a template.
656 *
657 * @param source the string to replace in, null returns null
658 * @return The result of the replace operation
659 */
660 public String replace(final String source) {
661 if (source == null) {
662 return null;
663 }
664 final StrBuilder buf = new StrBuilder(source);
665 if (!substitute(buf, 0, source.length())) {
666 return source;
667 }
668 return buf.toString();
669 }
670
671 /**
672 * Replaces all the occurrences of variables with their matching values
673 * from the resolver using the given source string as a template.
674 * <p>
675 * Only the specified portion of the string will be processed.
676 * The rest of the string is not processed, and is not returned.
677 * </p>
678 *
679 * @param source the string to replace in, null returns null
680 * @param offset the start offset within the array, must be valid
681 * @param length the length within the array to be processed, must be valid
682 * @return The result of the replace operation
683 */
684 public String replace(final String source, final int offset, final int length) {
685 if (source == null) {
686 return null;
687 }
688 final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
689 if (!substitute(buf, 0, length)) {
690 return source.substring(offset, offset + length);
691 }
692 return buf.toString();
693 }
694
695 /**
696 * Replaces all the occurrences of variables with their matching values
697 * from the resolver using the given source buffer as a template.
698 * The buffer is not altered by this method.
699 *
700 * @param source the buffer to use as a template, not changed, null returns null
701 * @return The result of the replace operation
702 */
703 public String replace(final StringBuffer source) {
704 if (source == null) {
705 return null;
706 }
707 final StrBuilder buf = new StrBuilder(source.length()).append(source);
708 substitute(buf, 0, buf.length());
709 return buf.toString();
710 }
711
712 /**
713 * Replaces all the occurrences of variables with their matching values
714 * from the resolver using the given source buffer as a template.
715 * The buffer is not altered by this method.
716 * <p>
717 * Only the specified portion of the buffer will be processed.
718 * The rest of the buffer is not processed, and is not returned.
719 * </p>
720 *
721 * @param source the buffer to use as a template, not changed, null returns null
722 * @param offset the start offset within the array, must be valid
723 * @param length the length within the array to be processed, must be valid
724 * @return The result of the replace operation
725 */
726 public String replace(final StringBuffer source, final int offset, final int length) {
727 if (source == null) {
728 return null;
729 }
730 final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
731 substitute(buf, 0, length);
732 return buf.toString();
733 }
734
735 /**
736 * Replaces all the occurrences of variables within the given source
737 * builder with their matching values from the resolver.
738 *
739 * @param source the builder to replace in, updated, null returns zero
740 * @return true if altered
741 */
742 public boolean replaceIn(final StrBuilder source) {
743 if (source == null) {
744 return false;
745 }
746 return substitute(source, 0, source.length());
747 }
748
749 /**
750 * Replaces all the occurrences of variables within the given source
751 * builder with their matching values from the resolver.
752 * <p>
753 * Only the specified portion of the builder will be processed.
754 * The rest of the builder is not processed, but it is not deleted.
755 * </p>
756 *
757 * @param source the builder to replace in, null returns zero
758 * @param offset the start offset within the array, must be valid
759 * @param length the length within the builder to be processed, must be valid
760 * @return true if altered
761 */
762 public boolean replaceIn(final StrBuilder source, final int offset, final int length) {
763 if (source == null) {
764 return false;
765 }
766 return substitute(source, offset, length);
767 }
768
769 /**
770 * Replaces all the occurrences of variables within the given source buffer
771 * with their matching values from the resolver.
772 * The buffer is updated with the result.
773 *
774 * @param source the buffer to replace in, updated, null returns zero
775 * @return true if altered
776 */
777 public boolean replaceIn(final StringBuffer source) {
778 if (source == null) {
779 return false;
780 }
781 return replaceIn(source, 0, source.length());
782 }
783
784 /**
785 * Replaces all the occurrences of variables within the given source buffer
786 * with their matching values from the resolver.
787 * The buffer is updated with the result.
788 * <p>
789 * Only the specified portion of the buffer will be processed.
790 * The rest of the buffer is not processed, but it is not deleted.
791 * </p>
792 *
793 * @param source the buffer to replace in, updated, null returns zero
794 * @param offset the start offset within the array, must be valid
795 * @param length the length within the buffer to be processed, must be valid
796 * @return true if altered
797 */
798 public boolean replaceIn(final StringBuffer source, final int offset, final int length) {
799 if (source == null) {
800 return false;
801 }
802 final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
803 if (!substitute(buf, 0, length)) {
804 return false;
805 }
806 source.replace(offset, offset + length, buf.toString());
807 return true;
808 }
809
810 /**
811 * Replaces all the occurrences of variables within the given source buffer
812 * with their matching values from the resolver.
813 * The buffer is updated with the result.
814 *
815 * @param source the buffer to replace in, updated, null returns zero
816 * @return true if altered
817 */
818 public boolean replaceIn(final StringBuilder source) {
819 if (source == null) {
820 return false;
821 }
822 return replaceIn(source, 0, source.length());
823 }
824
825 /**
826 * Replaces all the occurrences of variables within the given source builder
827 * with their matching values from the resolver.
828 * The builder is updated with the result.
829 * <p>
830 * Only the specified portion of the buffer will be processed.
831 * The rest of the buffer is not processed, but it is not deleted.
832 * </p>
833 *
834 * @param source the buffer to replace in, updated, null returns zero
835 * @param offset the start offset within the array, must be valid
836 * @param length the length within the buffer to be processed, must be valid
837 * @return true if altered
838 */
839 public boolean replaceIn(final StringBuilder source, final int offset, final int length) {
840 if (source == null) {
841 return false;
842 }
843 final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
844 if (!substitute(buf, 0, length)) {
845 return false;
846 }
847 source.replace(offset, offset + length, buf.toString());
848 return true;
849 }
850
851 /**
852 * Internal method that resolves the value of a variable.
853 * <p>
854 * Most users of this class do not need to call this method. This method is
855 * called automatically by the substitution process.
856 * </p>
857 * <p>
858 * Writers of subclasses can override this method if they need to alter
859 * how each substitution occurs. The method is passed the variable's name
860 * and must return the corresponding value. This implementation uses the
861 * {@link #getVariableResolver()} with the variable's name as the key.
862 * </p>
863 *
864 * @param variableName the name of the variable, not null
865 * @param buf the buffer where the substitution is occurring, not null
866 * @param startPos the start position of the variable including the prefix, valid
867 * @param endPos the end position of the variable including the suffix, valid
868 * @return The variable's value or <b>null</b> if the variable is unknown
869 */
870 protected String resolveVariable(final String variableName,
871 final StrBuilder buf,
872 final int startPos,
873 final int endPos) {
874 final StrLookup<?> resolver = getVariableResolver();
875 if (resolver == null) {
876 return null;
877 }
878 return resolver.lookup(variableName);
879 }
880
881 /**
882 * Sets a flag whether substitution is done in variable values (recursive).
883 *
884 * @param disableSubstitutionInValues true if substitution in variable value are disabled
885 *
886 * @since 1.2
887 */
888 public void setDisableSubstitutionInValues(final boolean disableSubstitutionInValues) {
889 this.disableSubstitutionInValues = disableSubstitutionInValues;
890 }
891
892 /**
893 * Sets a flag whether substitution is done in variable names. If set to
894 * <b>true</b>, the names of variables can contain other variables which are
895 * processed first before the original variable is evaluated, e.g.
896 * {@code ${jre-${java.version}}}. The default value is <b>false</b>.
897 *
898 * @param enableSubstitutionInVariables the new value of the flag
899 */
900 public void setEnableSubstitutionInVariables(
901 final boolean enableSubstitutionInVariables) {
902 this.enableSubstitutionInVariables = enableSubstitutionInVariables;
903 }
904
905 /**
906 * Sets the escape character.
907 * If this character is placed before a variable reference in the source
908 * text, this variable will be ignored.
909 *
910 * @param escapeCharacter the escape character (0 for disabling escaping)
911 */
912 public void setEscapeChar(final char escapeCharacter) {
913 this.escapeChar = escapeCharacter;
914 }
915
916 /**
917 * Sets a flag controlling whether escapes are preserved during
918 * substitution. If set to <b>true</b>, the escape character is retained
919 * during substitution (e.g. {@code $${this-is-escaped}} remains
920 * {@code $${this-is-escaped}}). If set to <b>false</b>, the escape
921 * character is removed during substitution (e.g.
922 * {@code $${this-is-escaped}} becomes
923 * {@code ${this-is-escaped}}). The default value is <b>false</b>
924 *
925 * @param preserveEscapes true if escapes are to be preserved
926 */
927 public void setPreserveEscapes(final boolean preserveEscapes) {
928 this.preserveEscapes = preserveEscapes;
929 }
930
931 /**
932 * Sets the variable default value delimiter to use.
933 * <p>
934 * The variable default value delimiter is the character or characters that delimit the
935 * variable name and the variable default value. This method allows a single character
936 * variable default value delimiter to be easily set.
937 * </p>
938 *
939 * @param valueDelimiter the variable default value delimiter character to use
940 * @return this, to enable chaining
941 */
942 public StrSubstitutor setValueDelimiter(final char valueDelimiter) {
943 return setValueDelimiterMatcher(StrMatcher.charMatcher(valueDelimiter));
944 }
945
946 /**
947 * Sets the variable default value delimiter to use.
948 * <p>
949 * The variable default value delimiter is the character or characters that delimit the
950 * variable name and the variable default value. This method allows a string
951 * variable default value delimiter to be easily set.
952 * </p>
953 * <p>
954 * If the {@code valueDelimiter} is null or empty string, then the variable default
955 * value resolution becomes disabled.
956 * </p>
957 *
958 * @param valueDelimiter the variable default value delimiter string to use, may be null or empty
959 * @return this, to enable chaining
960 */
961 public StrSubstitutor setValueDelimiter(final String valueDelimiter) {
962 if (valueDelimiter == null || valueDelimiter.isEmpty()) {
963 setValueDelimiterMatcher(null);
964 return this;
965 }
966 return setValueDelimiterMatcher(StrMatcher.stringMatcher(valueDelimiter));
967 }
968
969 /**
970 * Sets the variable default value delimiter matcher to use.
971 * <p>
972 * The variable default value delimiter is the character or characters that delimit the
973 * variable name and the variable default value. This delimiter is expressed in terms of a matcher
974 * allowing advanced variable default value delimiter matches.
975 * </p>
976 * <p>
977 * If the {@code valueDelimiterMatcher} is null, then the variable default value resolution
978 * becomes disabled.
979 * </p>
980 *
981 * @param valueDelimiterMatcher variable default value delimiter matcher to use, may be null
982 * @return this, to enable chaining
983 */
984 public StrSubstitutor setValueDelimiterMatcher(final StrMatcher valueDelimiterMatcher) {
985 this.valueDelimiterMatcher = valueDelimiterMatcher;
986 return this;
987 }
988
989 /**
990 * Sets the variable prefix to use.
991 * <p>
992 * The variable prefix is the character or characters that identify the
993 * start of a variable. This method allows a single character prefix to
994 * be easily set.
995 * </p>
996 *
997 * @param prefix the prefix character to use
998 * @return this, to enable chaining
999 */
1000 public StrSubstitutor setVariablePrefix(final char prefix) {
1001 return setVariablePrefixMatcher(StrMatcher.charMatcher(prefix));
1002 }
1003
1004 /**
1005 * Sets the variable prefix to use.
1006 * <p>
1007 * The variable prefix is the character or characters that identify the
1008 * start of a variable. This method allows a string prefix to be easily set.
1009 * </p>
1010 *
1011 * @param prefix the prefix for variables, not null
1012 * @return this, to enable chaining
1013 * @throws IllegalArgumentException if the prefix is null
1014 */
1015 public StrSubstitutor setVariablePrefix(final String prefix) {
1016 Validate.isTrue(prefix != null, "Variable prefix must not be null!");
1017 return setVariablePrefixMatcher(StrMatcher.stringMatcher(prefix));
1018 }
1019
1020 /**
1021 * Sets the variable prefix matcher currently in use.
1022 * <p>
1023 * The variable prefix is the character or characters that identify the
1024 * start of a variable. This prefix is expressed in terms of a matcher
1025 * allowing advanced prefix matches.
1026 * </p>
1027 *
1028 * @param prefixMatcher the prefix matcher to use, null ignored
1029 * @return this, to enable chaining
1030 * @throws IllegalArgumentException if the prefix matcher is null
1031 */
1032 public StrSubstitutor setVariablePrefixMatcher(final StrMatcher prefixMatcher) {
1033 Validate.isTrue(prefixMatcher != null, "Variable prefix matcher must not be null!");
1034 this.prefixMatcher = prefixMatcher;
1035 return this;
1036 }
1037
1038 /**
1039 * Sets the VariableResolver that is used to lookup variables.
1040 *
1041 * @param variableResolver the VariableResolver
1042 */
1043 public void setVariableResolver(final StrLookup<?> variableResolver) {
1044 this.variableResolver = variableResolver;
1045 }
1046
1047 /**
1048 * Sets the variable suffix to use.
1049 * <p>
1050 * The variable suffix is the character or characters that identify the
1051 * end of a variable. This method allows a single character suffix to
1052 * be easily set.
1053 * </p>
1054 *
1055 * @param suffix the suffix character to use
1056 * @return this, to enable chaining
1057 */
1058 public StrSubstitutor setVariableSuffix(final char suffix) {
1059 return setVariableSuffixMatcher(StrMatcher.charMatcher(suffix));
1060 }
1061
1062 /**
1063 * Sets the variable suffix to use.
1064 * <p>
1065 * The variable suffix is the character or characters that identify the
1066 * end of a variable. This method allows a string suffix to be easily set.
1067 * </p>
1068 *
1069 * @param suffix the suffix for variables, not null
1070 * @return this, to enable chaining
1071 * @throws IllegalArgumentException if the suffix is null
1072 */
1073 public StrSubstitutor setVariableSuffix(final String suffix) {
1074 Validate.isTrue(suffix != null, "Variable suffix must not be null!");
1075 return setVariableSuffixMatcher(StrMatcher.stringMatcher(suffix));
1076 }
1077
1078 /**
1079 * Sets the variable suffix matcher currently in use.
1080 * <p>
1081 * The variable suffix is the character or characters that identify the
1082 * end of a variable. This suffix is expressed in terms of a matcher
1083 * allowing advanced suffix matches.
1084 * </p>
1085 *
1086 * @param suffixMatcher the suffix matcher to use, null ignored
1087 * @return this, to enable chaining
1088 * @throws IllegalArgumentException if the suffix matcher is null
1089 */
1090 public StrSubstitutor setVariableSuffixMatcher(final StrMatcher suffixMatcher) {
1091 Validate.isTrue(suffixMatcher != null, "Variable suffix matcher must not be null!");
1092 this.suffixMatcher = suffixMatcher;
1093 return this;
1094 }
1095
1096 /**
1097 * Internal method that substitutes the variables.
1098 * <p>
1099 * Most users of this class do not need to call this method. This method will
1100 * be called automatically by another (public) method.
1101 * </p>
1102 * <p>
1103 * Writers of subclasses can override this method if they need access to
1104 * the substitution process at the start or end.
1105 * </p>
1106 *
1107 * @param buf the string builder to substitute into, not null
1108 * @param offset the start offset within the builder, must be valid
1109 * @param length the length within the builder to be processed, must be valid
1110 * @return true if altered
1111 */
1112 protected boolean substitute(final StrBuilder buf, final int offset, final int length) {
1113 return substitute(buf, offset, length, null) > 0;
1114 }
1115
1116 /**
1117 * Recursive handler for multiple levels of interpolation. This is the main
1118 * interpolation method, which resolves the values of all variable references
1119 * contained in the passed in text.
1120 *
1121 * @param buf the string builder to substitute into, not null
1122 * @param offset the start offset within the builder, must be valid
1123 * @param length the length within the builder to be processed, must be valid
1124 * @param priorVariables the stack keeping track of the replaced variables, may be null
1125 * @return The length change that occurs, unless priorVariables is null when the int
1126 * represents a boolean flag as to whether any change occurred.
1127 */
1128 private int substitute(final StrBuilder buf, final int offset, final int length, List<String> priorVariables) {
1129 final StrMatcher pfxMatcher = getVariablePrefixMatcher();
1130 final StrMatcher suffMatcher = getVariableSuffixMatcher();
1131 final char escape = getEscapeChar();
1132 final StrMatcher valueDelimMatcher = getValueDelimiterMatcher();
1133 final boolean substitutionInVariablesEnabled = isEnableSubstitutionInVariables();
1134 final boolean substitutionInValuesDisabled = isDisableSubstitutionInValues();
1135
1136 final boolean top = priorVariables == null;
1137 boolean altered = false;
1138 int lengthChange = 0;
1139 char[] chars = buf.buffer;
1140 int bufEnd = offset + length;
1141 int pos = offset;
1142 while (pos < bufEnd) {
1143 final int startMatchLen = pfxMatcher.isMatch(chars, pos, offset,
1144 bufEnd);
1145 if (startMatchLen == 0) {
1146 pos++;
1147 } else {
1148 // found variable start marker
1149 if (pos > offset && chars[pos - 1] == escape) {
1150 // escaped
1151 if (preserveEscapes) {
1152 pos++;
1153 continue;
1154 }
1155 buf.deleteCharAt(pos - 1);
1156 chars = buf.buffer; // in case buffer was altered
1157 lengthChange--;
1158 altered = true;
1159 bufEnd--;
1160 } else {
1161 // find suffix
1162 final int startPos = pos;
1163 pos += startMatchLen;
1164 int endMatchLen = 0;
1165 int nestedVarCount = 0;
1166 while (pos < bufEnd) {
1167 if (substitutionInVariablesEnabled
1168 && pfxMatcher.isMatch(chars,
1169 pos, offset, bufEnd) != 0) {
1170 // found a nested variable start
1171 endMatchLen = pfxMatcher.isMatch(chars,
1172 pos, offset, bufEnd);
1173 nestedVarCount++;
1174 pos += endMatchLen;
1175 continue;
1176 }
1177
1178 endMatchLen = suffMatcher.isMatch(chars, pos, offset,
1179 bufEnd);
1180 if (endMatchLen == 0) {
1181 pos++;
1182 } else {
1183 // found variable end marker
1184 if (nestedVarCount == 0) {
1185 String varNameExpr = new String(chars, startPos
1186 + startMatchLen, pos - startPos
1187 - startMatchLen);
1188 if (substitutionInVariablesEnabled) {
1189 final StrBuilder bufName = new StrBuilder(varNameExpr);
1190 substitute(bufName, 0, bufName.length());
1191 varNameExpr = bufName.toString();
1192 }
1193 pos += endMatchLen;
1194 final int endPos = pos;
1195
1196 String varName = varNameExpr;
1197 String varDefaultValue = null;
1198
1199 if (valueDelimMatcher != null) {
1200 final char[] varNameExprChars = varNameExpr.toCharArray();
1201 int valueDelimiterMatchLen = 0;
1202 for (int i = 0; i < varNameExprChars.length; i++) {
1203 // if there's any nested variable when nested variable substitution disabled,
1204 // then stop resolving name and default value.
1205 if (!substitutionInVariablesEnabled
1206 && pfxMatcher.isMatch(varNameExprChars,
1207 i,
1208 i,
1209 varNameExprChars.length) != 0) {
1210 break;
1211 }
1212 if (valueDelimMatcher.isMatch(varNameExprChars, i) != 0) {
1213 valueDelimiterMatchLen = valueDelimMatcher.isMatch(varNameExprChars, i);
1214 varName = varNameExpr.substring(0, i);
1215 varDefaultValue = varNameExpr.substring(i + valueDelimiterMatchLen);
1216 break;
1217 }
1218 }
1219 }
1220
1221 // on the first call initialize priorVariables
1222 if (priorVariables == null) {
1223 priorVariables = new ArrayList<>();
1224 priorVariables.add(new String(chars,
1225 offset, length));
1226 }
1227
1228 // handle cyclic substitution
1229 checkCyclicSubstitution(varName, priorVariables);
1230 priorVariables.add(varName);
1231
1232 // resolve the variable
1233 String varValue = resolveVariable(varName, buf,
1234 startPos, endPos);
1235 if (varValue == null) {
1236 varValue = varDefaultValue;
1237 }
1238 if (varValue != null) {
1239 final int varLen = varValue.length();
1240 buf.replace(startPos, endPos, varValue);
1241 altered = true;
1242 int change = 0;
1243 if (!substitutionInValuesDisabled) { // recursive replace
1244 change = substitute(buf, startPos,
1245 varLen, priorVariables);
1246 }
1247 change = change
1248 + varLen - (endPos - startPos);
1249 pos += change;
1250 bufEnd += change;
1251 lengthChange += change;
1252 chars = buf.buffer; // in case buffer was
1253 // altered
1254 }
1255
1256 // remove variable from the cyclic stack
1257 priorVariables
1258 .remove(priorVariables.size() - 1);
1259 break;
1260 }
1261 nestedVarCount--;
1262 pos += endMatchLen;
1263 }
1264 }
1265 }
1266 }
1267 }
1268 if (top) {
1269 return altered ? 1 : 0;
1270 }
1271 return lengthChange;
1272 }
1273 }