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.text; 018 019import java.util.ArrayList; 020import java.util.Enumeration; 021import java.util.HashMap; 022import java.util.List; 023import java.util.Map; 024import java.util.Properties; 025 026import org.apache.commons.lang3.StringUtils; 027 028/** 029 * Substitutes variables within a string by values. 030 * <p> 031 * This class takes a piece of text and substitutes all the variables within it. 032 * The default definition of a variable is {@code ${variableName}}. 033 * The prefix and suffix can be changed via constructors and set methods. 034 * <p> 035 * Variable values are typically resolved from a map, but could also be resolved 036 * from system properties, or by supplying a custom variable resolver. 037 * <p> 038 * The simplest example is to use this class to replace Java System properties. For example: 039 * <pre> 040 * StrSubstitutor.replaceSystemProperties( 041 * "You are running with java.version = ${java.version} and os.name = ${os.name}."); 042 * </pre> 043 * <p> 044 * Typical usage of this class follows the following pattern: First an instance is created 045 * and initialized with the map that contains the values for the available variables. 046 * If a prefix and/or suffix for variables should be used other than the default ones, 047 * the appropriate settings can be performed. After that the {@code replace()} 048 * method can be called passing in the source text for interpolation. In the returned 049 * text all variable references (as long as their values are known) will be resolved. 050 * The following example demonstrates this: 051 * <pre> 052 * Map valuesMap = HashMap(); 053 * valuesMap.put("animal", "quick brown fox"); 054 * valuesMap.put("target", "lazy dog"); 055 * String templateString = "The ${animal} jumps over the ${target}."; 056 * StrSubstitutor sub = new StrSubstitutor(valuesMap); 057 * String resolvedString = sub.replace(templateString); 058 * </pre> 059 * yielding: 060 * <pre> 061 * The quick brown fox jumps over the lazy dog. 062 * </pre> 063 * <p> 064 * Also, this class allows to set a default value for unresolved variables. 065 * The default value for a variable can be appended to the variable name after the variable 066 * default value delimiter. The default value of the variable default value delimiter is ':-', 067 * as in bash and other *nix shells, as those are arguably where the default ${} delimiter set originated. 068 * The variable default value delimiter can be manually set by calling {@link #setValueDelimiterMatcher(StrMatcher)}, 069 * {@link #setValueDelimiter(char)} or {@link #setValueDelimiter(String)}. 070 * The following shows an example with variable default value settings: 071 * <pre> 072 * Map valuesMap = HashMap(); 073 * valuesMap.put("animal", "quick brown fox"); 074 * valuesMap.put("target", "lazy dog"); 075 * String templateString = "The ${animal} jumps over the ${target}. ${undefined.number:-1234567890}."; 076 * StrSubstitutor sub = new StrSubstitutor(valuesMap); 077 * String resolvedString = sub.replace(templateString); 078 * </pre> 079 * yielding: 080 * <pre> 081 * The quick brown fox jumps over the lazy dog. 1234567890. 082 * </pre> 083 * <p> 084 * In addition to this usage pattern there are some static convenience methods that 085 * cover the most common use cases. These methods can be used without the need of 086 * manually creating an instance. However if multiple replace operations are to be 087 * performed, creating and reusing an instance of this class will be more efficient. 088 * <p> 089 * Variable replacement works in a recursive way. Thus, if a variable value contains 090 * a variable then that variable will also be replaced. Cyclic replacements are 091 * detected and will cause an exception to be thrown. 092 * <p> 093 * Sometimes the interpolation's result must contain a variable prefix. As an example 094 * take the following source text: 095 * <pre> 096 * The variable ${${name}} must be used. 097 * </pre> 098 * Here only the variable's name referred to in the text should be replaced resulting 099 * 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 2.2 124 * @deprecated as of 3.6, use commons-text 125 * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/StringSubstitutor.html"> 126 * StringSubstitutor</a> instead 127 */ 128@Deprecated 129public class StrSubstitutor { 130 131 /** 132 * Constant for the default escape character. 133 */ 134 public static final char DEFAULT_ESCAPE = '$'; 135 /** 136 * Constant for the default variable prefix. 137 */ 138 public static final StrMatcher DEFAULT_PREFIX = StrMatcher.stringMatcher("${"); 139 /** 140 * Constant for the default variable suffix. 141 */ 142 public static final StrMatcher DEFAULT_SUFFIX = StrMatcher.stringMatcher("}"); 143 /** 144 * Constant for the default value delimiter of a variable. 145 * @since 3.2 146 */ 147 public static final StrMatcher DEFAULT_VALUE_DELIMITER = StrMatcher.stringMatcher(":-"); 148 149 /** 150 * Stores the escape character. 151 */ 152 private char escapeChar; 153 /** 154 * Stores the variable prefix. 155 */ 156 private StrMatcher prefixMatcher; 157 /** 158 * Stores the variable suffix. 159 */ 160 private StrMatcher suffixMatcher; 161 /** 162 * Stores the default variable value delimiter 163 */ 164 private StrMatcher valueDelimiterMatcher; 165 /** 166 * Variable resolution is delegated to an implementor of VariableResolver. 167 */ 168 private StrLookup<?> variableResolver; 169 /** 170 * The flag whether substitution in variable names is enabled. 171 */ 172 private boolean enableSubstitutionInVariables; 173 /** 174 * Whether escapes should be preserved. Default is false; 175 */ 176 private boolean preserveEscapes; 177 178 //----------------------------------------------------------------------- 179 /** 180 * Replaces all the occurrences of variables in the given source object with 181 * their matching values from the map. 182 * 183 * @param <V> the type of the values in the map 184 * @param source the source text containing the variables to substitute, null returns null 185 * @param valueMap the map with the values, may be null 186 * @return the result of the replace operation 187 */ 188 public static <V> String replace(final Object source, final Map<String, V> valueMap) { 189 return new StrSubstitutor(valueMap).replace(source); 190 } 191 192 /** 193 * Replaces all the occurrences of variables in the given source object with 194 * their matching values from the map. This method allows to specify a 195 * custom variable prefix and suffix 196 * 197 * @param <V> the type of the values in the map 198 * @param source the source text containing the variables to substitute, null returns null 199 * @param valueMap the map with the values, may be null 200 * @param prefix the prefix of variables, not null 201 * @param suffix the suffix of variables, not null 202 * @return the result of the replace operation 203 * @throws IllegalArgumentException if the prefix or suffix is null 204 */ 205 public static <V> String replace(final Object source, final Map<String, V> valueMap, final String prefix, final String suffix) { 206 return new StrSubstitutor(valueMap, prefix, suffix).replace(source); 207 } 208 209 /** 210 * Replaces all the occurrences of variables in the given source object with their matching 211 * values from the properties. 212 * 213 * @param source the source text containing the variables to substitute, null returns null 214 * @param valueProperties the properties with values, may be null 215 * @return the result of the replace operation 216 */ 217 public static String replace(final Object source, final Properties valueProperties) { 218 if (valueProperties == null) { 219 return source.toString(); 220 } 221 final Map<String, String> valueMap = new HashMap<>(); 222 final Enumeration<?> propNames = valueProperties.propertyNames(); 223 while (propNames.hasMoreElements()) { 224 final String propName = (String) propNames.nextElement(); 225 final String propValue = valueProperties.getProperty(propName); 226 valueMap.put(propName, propValue); 227 } 228 return replace(source, valueMap); 229 } 230 231 /** 232 * Replaces all the occurrences of variables in the given source object with 233 * their matching values from the system properties. 234 * 235 * @param source the source text containing the variables to substitute, null returns null 236 * @return the result of the replace operation 237 */ 238 public static String replaceSystemProperties(final Object source) { 239 return new StrSubstitutor(StrLookup.systemPropertiesLookup()).replace(source); 240 } 241 242 //----------------------------------------------------------------------- 243 /** 244 * Creates a new instance with defaults for variable prefix and suffix 245 * and the escaping character. 246 */ 247 public StrSubstitutor() { 248 this(null, DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE); 249 } 250 251 /** 252 * Creates a new instance and initializes it. Uses defaults for variable 253 * prefix and suffix and the escaping character. 254 * 255 * @param <V> the type of the values in the map 256 * @param valueMap the map with the variables' values, may be null 257 */ 258 public <V> StrSubstitutor(final Map<String, V> valueMap) { 259 this(StrLookup.mapLookup(valueMap), DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE); 260 } 261 262 /** 263 * Creates a new instance and initializes it. Uses a default escaping character. 264 * 265 * @param <V> the type of the values in the map 266 * @param valueMap the map with the variables' values, may be null 267 * @param prefix the prefix for variables, not null 268 * @param suffix the suffix for variables, not null 269 * @throws IllegalArgumentException if the prefix or suffix is null 270 */ 271 public <V> StrSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix) { 272 this(StrLookup.mapLookup(valueMap), prefix, suffix, DEFAULT_ESCAPE); 273 } 274 275 /** 276 * Creates a new instance and initializes it. 277 * 278 * @param <V> the type of the values in the map 279 * @param valueMap the map with the variables' values, may be null 280 * @param prefix the prefix for variables, not null 281 * @param suffix the suffix for variables, not null 282 * @param escape the escape character 283 * @throws IllegalArgumentException if the prefix or suffix is null 284 */ 285 public <V> StrSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix, 286 final char escape) { 287 this(StrLookup.mapLookup(valueMap), prefix, suffix, escape); 288 } 289 290 /** 291 * Creates a new instance and initializes it. 292 * 293 * @param <V> the type of the values in the map 294 * @param valueMap the map with the variables' values, may be null 295 * @param prefix the prefix for variables, not null 296 * @param suffix the suffix for variables, not null 297 * @param escape the escape character 298 * @param valueDelimiter the variable default value delimiter, may be null 299 * @throws IllegalArgumentException if the prefix or suffix is null 300 * @since 3.2 301 */ 302 public <V> StrSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix, 303 final char escape, final String valueDelimiter) { 304 this(StrLookup.mapLookup(valueMap), prefix, suffix, escape, valueDelimiter); 305 } 306 307 /** 308 * Creates a new instance and initializes it. 309 * 310 * @param variableResolver the variable resolver, may be null 311 */ 312 public StrSubstitutor(final StrLookup<?> variableResolver) { 313 this(variableResolver, DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE); 314 } 315 316 /** 317 * Creates a new instance and initializes it. 318 * 319 * @param variableResolver the variable resolver, may be null 320 * @param prefix the prefix for variables, not null 321 * @param suffix the suffix for variables, not null 322 * @param escape the escape character 323 * @throws IllegalArgumentException if the prefix or suffix is null 324 */ 325 public StrSubstitutor(final StrLookup<?> variableResolver, final String prefix, final String suffix, 326 final char escape) { 327 this.setVariableResolver(variableResolver); 328 this.setVariablePrefix(prefix); 329 this.setVariableSuffix(suffix); 330 this.setEscapeChar(escape); 331 this.setValueDelimiterMatcher(DEFAULT_VALUE_DELIMITER); 332 } 333 334 /** 335 * Creates a new instance and initializes it. 336 * 337 * @param variableResolver the variable resolver, may be null 338 * @param prefix the prefix for variables, not null 339 * @param suffix the suffix for variables, not null 340 * @param escape the escape character 341 * @param valueDelimiter the variable default value delimiter string, may be null 342 * @throws IllegalArgumentException if the prefix or suffix is null 343 * @since 3.2 344 */ 345 public StrSubstitutor(final StrLookup<?> variableResolver, final String prefix, final String suffix, 346 final char escape, final String valueDelimiter) { 347 this.setVariableResolver(variableResolver); 348 this.setVariablePrefix(prefix); 349 this.setVariableSuffix(suffix); 350 this.setEscapeChar(escape); 351 this.setValueDelimiter(valueDelimiter); 352 } 353 354 /** 355 * Creates a new instance and initializes it. 356 * 357 * @param variableResolver the variable resolver, may be null 358 * @param prefixMatcher the prefix for variables, not null 359 * @param suffixMatcher the suffix for variables, not null 360 * @param escape the escape character 361 * @throws IllegalArgumentException if the prefix or suffix is null 362 */ 363 public StrSubstitutor( 364 final StrLookup<?> variableResolver, final StrMatcher prefixMatcher, final StrMatcher suffixMatcher, 365 final char escape) { 366 this(variableResolver, prefixMatcher, suffixMatcher, escape, DEFAULT_VALUE_DELIMITER); 367 } 368 369 /** 370 * Creates a new instance and initializes it. 371 * 372 * @param variableResolver the variable resolver, may be null 373 * @param prefixMatcher the prefix for variables, not null 374 * @param suffixMatcher the suffix for variables, not null 375 * @param escape the escape character 376 * @param valueDelimiterMatcher the variable default value delimiter matcher, may be null 377 * @throws IllegalArgumentException if the prefix or suffix is null 378 * @since 3.2 379 */ 380 public StrSubstitutor( 381 final StrLookup<?> variableResolver, final StrMatcher prefixMatcher, final StrMatcher suffixMatcher, 382 final char escape, final StrMatcher valueDelimiterMatcher) { 383 this.setVariableResolver(variableResolver); 384 this.setVariablePrefixMatcher(prefixMatcher); 385 this.setVariableSuffixMatcher(suffixMatcher); 386 this.setEscapeChar(escape); 387 this.setValueDelimiterMatcher(valueDelimiterMatcher); 388 } 389 390 //----------------------------------------------------------------------- 391 /** 392 * Replaces all the occurrences of variables with their matching values 393 * from the resolver using the given source string as a template. 394 * 395 * @param source the string to replace in, null returns null 396 * @return the result of the replace operation 397 */ 398 public String replace(final String source) { 399 if (source == null) { 400 return null; 401 } 402 final StrBuilder buf = new StrBuilder(source); 403 if (substitute(buf, 0, source.length()) == false) { 404 return source; 405 } 406 return buf.toString(); 407 } 408 409 /** 410 * Replaces all the occurrences of variables with their matching values 411 * from the resolver using the given source string as a template. 412 * <p> 413 * Only the specified portion of the string will be processed. 414 * The rest of the string is not processed, and is not returned. 415 * 416 * @param source the string to replace in, null returns null 417 * @param offset the start offset within the array, must be valid 418 * @param length the length within the array to be processed, must be valid 419 * @return the result of the replace operation 420 */ 421 public String replace(final String source, final int offset, final int length) { 422 if (source == null) { 423 return null; 424 } 425 final StrBuilder buf = new StrBuilder(length).append(source, offset, length); 426 if (substitute(buf, 0, length) == false) { 427 return source.substring(offset, offset + length); 428 } 429 return buf.toString(); 430 } 431 432 //----------------------------------------------------------------------- 433 /** 434 * Replaces all the occurrences of variables with their matching values 435 * from the resolver using the given source array as a template. 436 * The array is not altered by this method. 437 * 438 * @param source the character array to replace in, not altered, null returns null 439 * @return the result of the replace operation 440 */ 441 public String replace(final char[] source) { 442 if (source == null) { 443 return null; 444 } 445 final StrBuilder buf = new StrBuilder(source.length).append(source); 446 substitute(buf, 0, source.length); 447 return buf.toString(); 448 } 449 450 /** 451 * Replaces all the occurrences of variables with their matching values 452 * from the resolver using the given source array as a template. 453 * The array is not altered by this method. 454 * <p> 455 * Only the specified portion of the array will be processed. 456 * The rest of the array is not processed, and is not returned. 457 * 458 * @param source the character array to replace in, not altered, null returns null 459 * @param offset the start offset within the array, must be valid 460 * @param length the length within the array to be processed, must be valid 461 * @return the result of the replace operation 462 */ 463 public String replace(final char[] source, final int offset, final int length) { 464 if (source == null) { 465 return null; 466 } 467 final StrBuilder buf = new StrBuilder(length).append(source, offset, length); 468 substitute(buf, 0, length); 469 return buf.toString(); 470 } 471 472 //----------------------------------------------------------------------- 473 /** 474 * Replaces all the occurrences of variables with their matching values 475 * from the resolver using the given source buffer as a template. 476 * The buffer is not altered by this method. 477 * 478 * @param source the buffer to use as a template, not changed, null returns null 479 * @return the result of the replace operation 480 */ 481 public String replace(final StringBuffer source) { 482 if (source == null) { 483 return null; 484 } 485 final StrBuilder buf = new StrBuilder(source.length()).append(source); 486 substitute(buf, 0, buf.length()); 487 return buf.toString(); 488 } 489 490 /** 491 * Replaces all the occurrences of variables with their matching values 492 * from the resolver using the given source buffer as a template. 493 * The buffer is not altered by this method. 494 * <p> 495 * Only the specified portion of the buffer will be processed. 496 * The rest of the buffer is not processed, and is not returned. 497 * 498 * @param source the buffer to use as a template, not changed, null returns null 499 * @param offset the start offset within the array, must be valid 500 * @param length the length within the array to be processed, must be valid 501 * @return the result of the replace operation 502 */ 503 public String replace(final StringBuffer source, final int offset, final int length) { 504 if (source == null) { 505 return null; 506 } 507 final StrBuilder buf = new StrBuilder(length).append(source, offset, length); 508 substitute(buf, 0, length); 509 return buf.toString(); 510 } 511 512 /** 513 * Replaces all the occurrences of variables with their matching values 514 * from the resolver using the given source as a template. 515 * The source is not altered by this method. 516 * 517 * @param source the buffer to use as a template, not changed, null returns null 518 * @return the result of the replace operation 519 * @since 3.2 520 */ 521 public String replace(final CharSequence source) { 522 if (source == null) { 523 return null; 524 } 525 return replace(source, 0, source.length()); 526 } 527 528 /** 529 * Replaces all the occurrences of variables with their matching values 530 * from the resolver using the given source as a template. 531 * The source is not altered by this method. 532 * <p> 533 * Only the specified portion of the buffer will be processed. 534 * The rest of the buffer is not processed, and is not returned. 535 * 536 * @param source the buffer to use as a template, not changed, null returns null 537 * @param offset the start offset within the array, must be valid 538 * @param length the length within the array to be processed, must be valid 539 * @return the result of the replace operation 540 * @since 3.2 541 */ 542 public String replace(final CharSequence source, final int offset, final int length) { 543 if (source == null) { 544 return null; 545 } 546 final StrBuilder buf = new StrBuilder(length).append(source, offset, length); 547 substitute(buf, 0, length); 548 return buf.toString(); 549 } 550 551 //----------------------------------------------------------------------- 552 /** 553 * Replaces all the occurrences of variables with their matching values 554 * from the resolver using the given source builder as a template. 555 * The builder is not altered by this method. 556 * 557 * @param source the builder to use as a template, not changed, null returns null 558 * @return the result of the replace operation 559 */ 560 public String replace(final StrBuilder source) { 561 if (source == null) { 562 return null; 563 } 564 final StrBuilder buf = new StrBuilder(source.length()).append(source); 565 substitute(buf, 0, buf.length()); 566 return buf.toString(); 567 } 568 569 /** 570 * Replaces all the occurrences of variables with their matching values 571 * from the resolver using the given source builder as a template. 572 * The builder is not altered by this method. 573 * <p> 574 * Only the specified portion of the builder will be processed. 575 * The rest of the builder is not processed, and is not returned. 576 * 577 * @param source the builder to use as a template, not changed, null returns null 578 * @param offset the start offset within the array, must be valid 579 * @param length the length within the array to be processed, must be valid 580 * @return the result of the replace operation 581 */ 582 public String replace(final StrBuilder source, final int offset, final int length) { 583 if (source == null) { 584 return null; 585 } 586 final StrBuilder buf = new StrBuilder(length).append(source, offset, length); 587 substitute(buf, 0, length); 588 return buf.toString(); 589 } 590 591 //----------------------------------------------------------------------- 592 /** 593 * Replaces all the occurrences of variables in the given source object with 594 * their matching values from the resolver. The input source object is 595 * converted to a string using {@code toString} and is not altered. 596 * 597 * @param source the source to replace in, null returns null 598 * @return the result of the replace operation 599 */ 600 public String replace(final Object source) { 601 if (source == null) { 602 return null; 603 } 604 final StrBuilder buf = new StrBuilder().append(source); 605 substitute(buf, 0, buf.length()); 606 return buf.toString(); 607 } 608 609 //----------------------------------------------------------------------- 610 /** 611 * Replaces all the occurrences of variables within the given source buffer 612 * with their matching values from the resolver. 613 * The buffer is updated with the result. 614 * 615 * @param source the buffer to replace in, updated, null returns zero 616 * @return true if altered 617 */ 618 public boolean replaceIn(final StringBuffer source) { 619 if (source == null) { 620 return false; 621 } 622 return replaceIn(source, 0, source.length()); 623 } 624 625 /** 626 * Replaces all the occurrences of variables within the given source buffer 627 * with their matching values from the resolver. 628 * The buffer is updated with the result. 629 * <p> 630 * Only the specified portion of the buffer will be processed. 631 * The rest of the buffer is not processed, but it is not deleted. 632 * 633 * @param source the buffer to replace in, updated, null returns zero 634 * @param offset the start offset within the array, must be valid 635 * @param length the length within the buffer to be processed, must be valid 636 * @return true if altered 637 */ 638 public boolean replaceIn(final StringBuffer source, final int offset, final int length) { 639 if (source == null) { 640 return false; 641 } 642 final StrBuilder buf = new StrBuilder(length).append(source, offset, length); 643 if (substitute(buf, 0, length) == false) { 644 return false; 645 } 646 source.replace(offset, offset + length, buf.toString()); 647 return true; 648 } 649 650 //----------------------------------------------------------------------- 651 /** 652 * Replaces all the occurrences of variables within the given source buffer 653 * with their matching values from the resolver. 654 * The buffer is updated with the result. 655 * 656 * @param source the buffer to replace in, updated, null returns zero 657 * @return true if altered 658 * @since 3.2 659 */ 660 public boolean replaceIn(final StringBuilder source) { 661 if (source == null) { 662 return false; 663 } 664 return replaceIn(source, 0, source.length()); 665 } 666 667 /** 668 * Replaces all the occurrences of variables within the given source builder 669 * with their matching values from the resolver. 670 * The builder is updated with the result. 671 * <p> 672 * Only the specified portion of the buffer will be processed. 673 * The rest of the buffer is not processed, but it is not deleted. 674 * 675 * @param source the buffer to replace in, updated, null returns zero 676 * @param offset the start offset within the array, must be valid 677 * @param length the length within the buffer to be processed, must be valid 678 * @return true if altered 679 * @since 3.2 680 */ 681 public boolean replaceIn(final StringBuilder source, final int offset, final int length) { 682 if (source == null) { 683 return false; 684 } 685 final StrBuilder buf = new StrBuilder(length).append(source, offset, length); 686 if (substitute(buf, 0, length) == false) { 687 return false; 688 } 689 source.replace(offset, offset + length, buf.toString()); 690 return true; 691 } 692 693 //----------------------------------------------------------------------- 694 /** 695 * Replaces all the occurrences of variables within the given source 696 * builder with their matching values from the resolver. 697 * 698 * @param source the builder to replace in, updated, null returns zero 699 * @return true if altered 700 */ 701 public boolean replaceIn(final StrBuilder source) { 702 if (source == null) { 703 return false; 704 } 705 return substitute(source, 0, source.length()); 706 } 707 708 /** 709 * Replaces all the occurrences of variables within the given source 710 * builder with their matching values from the resolver. 711 * <p> 712 * Only the specified portion of the builder will be processed. 713 * The rest of the builder is not processed, but it is not deleted. 714 * 715 * @param source the builder to replace in, null returns zero 716 * @param offset the start offset within the array, must be valid 717 * @param length the length within the builder to be processed, must be valid 718 * @return true if altered 719 */ 720 public boolean replaceIn(final StrBuilder source, final int offset, final int length) { 721 if (source == null) { 722 return false; 723 } 724 return substitute(source, offset, length); 725 } 726 727 //----------------------------------------------------------------------- 728 /** 729 * Internal method that substitutes the variables. 730 * <p> 731 * Most users of this class do not need to call this method. This method will 732 * be called automatically by another (public) method. 733 * <p> 734 * Writers of subclasses can override this method if they need access to 735 * the substitution process at the start or end. 736 * 737 * @param buf the string builder to substitute into, not null 738 * @param offset the start offset within the builder, must be valid 739 * @param length the length within the builder to be processed, must be valid 740 * @return true if altered 741 */ 742 protected boolean substitute(final StrBuilder buf, final int offset, final int length) { 743 return substitute(buf, offset, length, null) > 0; 744 } 745 746 /** 747 * Recursive handler for multiple levels of interpolation. This is the main 748 * interpolation method, which resolves the values of all variable references 749 * contained in the passed in text. 750 * 751 * @param buf the string builder to substitute into, not null 752 * @param offset the start offset within the builder, must be valid 753 * @param length the length within the builder to be processed, must be valid 754 * @param priorVariables the stack keeping track of the replaced variables, may be null 755 * @return the length change that occurs, unless priorVariables is null when the int 756 * represents a boolean flag as to whether any change occurred. 757 */ 758 private int substitute(final StrBuilder buf, final int offset, final int length, List<String> priorVariables) { 759 final StrMatcher pfxMatcher = getVariablePrefixMatcher(); 760 final StrMatcher suffMatcher = getVariableSuffixMatcher(); 761 final char escape = getEscapeChar(); 762 final StrMatcher valueDelimMatcher = getValueDelimiterMatcher(); 763 final boolean substitutionInVariablesEnabled = isEnableSubstitutionInVariables(); 764 765 final boolean top = priorVariables == null; 766 boolean altered = false; 767 int lengthChange = 0; 768 char[] chars = buf.buffer; 769 int bufEnd = offset + length; 770 int pos = offset; 771 while (pos < bufEnd) { 772 final int startMatchLen = pfxMatcher.isMatch(chars, pos, offset, 773 bufEnd); 774 if (startMatchLen == 0) { 775 pos++; 776 } else // found variable start marker 777 if (pos > offset && chars[pos - 1] == escape) { 778 // escaped 779 if (preserveEscapes) { 780 pos++; 781 continue; 782 } 783 buf.deleteCharAt(pos - 1); 784 chars = buf.buffer; // in case buffer was altered 785 lengthChange--; 786 altered = true; 787 bufEnd--; 788 } else { 789 // find suffix 790 final int startPos = pos; 791 pos += startMatchLen; 792 int endMatchLen = 0; 793 int nestedVarCount = 0; 794 while (pos < bufEnd) { 795 if (substitutionInVariablesEnabled 796 && (endMatchLen = pfxMatcher.isMatch(chars, 797 pos, offset, bufEnd)) != 0) { 798 // found a nested variable start 799 nestedVarCount++; 800 pos += endMatchLen; 801 continue; 802 } 803 804 endMatchLen = suffMatcher.isMatch(chars, pos, offset, 805 bufEnd); 806 if (endMatchLen == 0) { 807 pos++; 808 } else { 809 // found variable end marker 810 if (nestedVarCount == 0) { 811 String varNameExpr = new String(chars, startPos 812 + startMatchLen, pos - startPos 813 - startMatchLen); 814 if (substitutionInVariablesEnabled) { 815 final StrBuilder bufName = new StrBuilder(varNameExpr); 816 substitute(bufName, 0, bufName.length()); 817 varNameExpr = bufName.toString(); 818 } 819 pos += endMatchLen; 820 final int endPos = pos; 821 822 String varName = varNameExpr; 823 String varDefaultValue = null; 824 825 if (valueDelimMatcher != null) { 826 final char [] varNameExprChars = varNameExpr.toCharArray(); 827 int valueDelimiterMatchLen = 0; 828 for (int i = 0; i < varNameExprChars.length; i++) { 829 // if there's any nested variable when nested variable substitution disabled, then stop resolving name and default value. 830 if (!substitutionInVariablesEnabled 831 && pfxMatcher.isMatch(varNameExprChars, i, i, varNameExprChars.length) != 0) { 832 break; 833 } 834 if ((valueDelimiterMatchLen = valueDelimMatcher.isMatch(varNameExprChars, i)) != 0) { 835 varName = varNameExpr.substring(0, i); 836 varDefaultValue = varNameExpr.substring(i + valueDelimiterMatchLen); 837 break; 838 } 839 } 840 } 841 842 // on the first call initialize priorVariables 843 if (priorVariables == null) { 844 priorVariables = new ArrayList<>(); 845 priorVariables.add(new String(chars, 846 offset, length)); 847 } 848 849 // handle cyclic substitution 850 checkCyclicSubstitution(varName, priorVariables); 851 priorVariables.add(varName); 852 853 // resolve the variable 854 String varValue = resolveVariable(varName, buf, 855 startPos, endPos); 856 if (varValue == null) { 857 varValue = varDefaultValue; 858 } 859 if (varValue != null) { 860 // recursive replace 861 final int varLen = varValue.length(); 862 buf.replace(startPos, endPos, varValue); 863 altered = true; 864 int change = substitute(buf, startPos, 865 varLen, priorVariables); 866 change = change 867 + varLen - (endPos - startPos); 868 pos += change; 869 bufEnd += change; 870 lengthChange += change; 871 chars = buf.buffer; // in case buffer was 872 // altered 873 } 874 875 // remove variable from the cyclic stack 876 priorVariables 877 .remove(priorVariables.size() - 1); 878 break; 879 } 880 nestedVarCount--; 881 pos += endMatchLen; 882 } 883 } 884 } 885 } 886 if (top) { 887 return altered ? 1 : 0; 888 } 889 return lengthChange; 890 } 891 892 /** 893 * Checks if the specified variable is already in the stack (list) of variables. 894 * 895 * @param varName the variable name to check 896 * @param priorVariables the list of prior variables 897 */ 898 private void checkCyclicSubstitution(final String varName, final List<String> priorVariables) { 899 if (priorVariables.contains(varName) == false) { 900 return; 901 } 902 final StrBuilder buf = new StrBuilder(256); 903 buf.append("Infinite loop in property interpolation of "); 904 buf.append(priorVariables.remove(0)); 905 buf.append(": "); 906 buf.appendWithSeparators(priorVariables, "->"); 907 throw new IllegalStateException(buf.toString()); 908 } 909 910 /** 911 * Internal method that resolves the value of a variable. 912 * <p> 913 * Most users of this class do not need to call this method. This method is 914 * called automatically by the substitution process. 915 * <p> 916 * Writers of subclasses can override this method if they need to alter 917 * how each substitution occurs. The method is passed the variable's name 918 * and must return the corresponding value. This implementation uses the 919 * {@link #getVariableResolver()} with the variable's name as the key. 920 * 921 * @param variableName the name of the variable, not null 922 * @param buf the buffer where the substitution is occurring, not null 923 * @param startPos the start position of the variable including the prefix, valid 924 * @param endPos the end position of the variable including the suffix, valid 925 * @return the variable's value or <b>null</b> if the variable is unknown 926 */ 927 protected String resolveVariable(final String variableName, final StrBuilder buf, final int startPos, final int endPos) { 928 final StrLookup<?> resolver = getVariableResolver(); 929 if (resolver == null) { 930 return null; 931 } 932 return resolver.lookup(variableName); 933 } 934 935 // Escape 936 //----------------------------------------------------------------------- 937 /** 938 * Returns the escape character. 939 * 940 * @return the character used for escaping variable references 941 */ 942 public char getEscapeChar() { 943 return this.escapeChar; 944 } 945 946 /** 947 * Sets the escape character. 948 * If this character is placed before a variable reference in the source 949 * text, this variable will be ignored. 950 * 951 * @param escapeCharacter the escape character (0 for disabling escaping) 952 */ 953 public void setEscapeChar(final char escapeCharacter) { 954 this.escapeChar = escapeCharacter; 955 } 956 957 // Prefix 958 //----------------------------------------------------------------------- 959 /** 960 * Gets the variable prefix matcher currently in use. 961 * <p> 962 * The variable prefix is the character or characters that identify the 963 * start of a variable. This prefix is expressed in terms of a matcher 964 * allowing advanced prefix matches. 965 * 966 * @return the prefix matcher in use 967 */ 968 public StrMatcher getVariablePrefixMatcher() { 969 return prefixMatcher; 970 } 971 972 /** 973 * Sets the variable prefix matcher currently in use. 974 * <p> 975 * The variable prefix is the character or characters that identify the 976 * start of a variable. This prefix is expressed in terms of a matcher 977 * allowing advanced prefix matches. 978 * 979 * @param prefixMatcher the prefix matcher to use, null ignored 980 * @return this, to enable chaining 981 * @throws IllegalArgumentException if the prefix matcher is null 982 */ 983 public StrSubstitutor setVariablePrefixMatcher(final StrMatcher prefixMatcher) { 984 if (prefixMatcher == null) { 985 throw new IllegalArgumentException("Variable prefix matcher must not be null."); 986 } 987 this.prefixMatcher = prefixMatcher; 988 return this; 989 } 990 991 /** 992 * Sets the variable prefix to use. 993 * <p> 994 * The variable prefix is the character or characters that identify the 995 * start of a variable. This method allows a single character prefix to 996 * be easily set. 997 * 998 * @param prefix the prefix character to use 999 * @return this, to enable chaining 1000 */ 1001 public StrSubstitutor setVariablePrefix(final char prefix) { 1002 return setVariablePrefixMatcher(StrMatcher.charMatcher(prefix)); 1003 } 1004 1005 /** 1006 * Sets the variable prefix to use. 1007 * <p> 1008 * The variable prefix is the character or characters that identify the 1009 * start of a variable. This method allows a string prefix to be easily set. 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 if (prefix == null) { 1017 throw new IllegalArgumentException("Variable prefix must not be null."); 1018 } 1019 return setVariablePrefixMatcher(StrMatcher.stringMatcher(prefix)); 1020 } 1021 1022 // Suffix 1023 //----------------------------------------------------------------------- 1024 /** 1025 * Gets the variable suffix matcher currently in use. 1026 * <p> 1027 * The variable suffix is the character or characters that identify the 1028 * end of a variable. This suffix is expressed in terms of a matcher 1029 * allowing advanced suffix matches. 1030 * 1031 * @return the suffix matcher in use 1032 */ 1033 public StrMatcher getVariableSuffixMatcher() { 1034 return suffixMatcher; 1035 } 1036 1037 /** 1038 * Sets the variable suffix matcher currently in use. 1039 * <p> 1040 * The variable suffix is the character or characters that identify the 1041 * end of a variable. This suffix is expressed in terms of a matcher 1042 * allowing advanced suffix matches. 1043 * 1044 * @param suffixMatcher the suffix matcher to use, null ignored 1045 * @return this, to enable chaining 1046 * @throws IllegalArgumentException if the suffix matcher is null 1047 */ 1048 public StrSubstitutor setVariableSuffixMatcher(final StrMatcher suffixMatcher) { 1049 if (suffixMatcher == null) { 1050 throw new IllegalArgumentException("Variable suffix matcher must not be null."); 1051 } 1052 this.suffixMatcher = suffixMatcher; 1053 return this; 1054 } 1055 1056 /** 1057 * Sets the variable suffix to use. 1058 * <p> 1059 * The variable suffix is the character or characters that identify the 1060 * end of a variable. This method allows a single character suffix to 1061 * be easily set. 1062 * 1063 * @param suffix the suffix character to use 1064 * @return this, to enable chaining 1065 */ 1066 public StrSubstitutor setVariableSuffix(final char suffix) { 1067 return setVariableSuffixMatcher(StrMatcher.charMatcher(suffix)); 1068 } 1069 1070 /** 1071 * Sets the variable suffix to use. 1072 * <p> 1073 * The variable suffix is the character or characters that identify the 1074 * end of a variable. This method allows a string suffix to be easily set. 1075 * 1076 * @param suffix the suffix for variables, not null 1077 * @return this, to enable chaining 1078 * @throws IllegalArgumentException if the suffix is null 1079 */ 1080 public StrSubstitutor setVariableSuffix(final String suffix) { 1081 if (suffix == null) { 1082 throw new IllegalArgumentException("Variable suffix must not be null."); 1083 } 1084 return setVariableSuffixMatcher(StrMatcher.stringMatcher(suffix)); 1085 } 1086 1087 // Variable Default Value Delimiter 1088 //----------------------------------------------------------------------- 1089 /** 1090 * Gets the variable default value delimiter matcher currently in use. 1091 * <p> 1092 * The variable default value delimiter is the character or characters that delimit the 1093 * variable name and the variable default value. This delimiter is expressed in terms of a matcher 1094 * allowing advanced variable default value delimiter matches. 1095 * <p> 1096 * If it returns null, then the variable default value resolution is disabled. 1097 * 1098 * @return the variable default value delimiter matcher in use, may be null 1099 * @since 3.2 1100 */ 1101 public StrMatcher getValueDelimiterMatcher() { 1102 return valueDelimiterMatcher; 1103 } 1104 1105 /** 1106 * Sets the variable default value delimiter matcher to use. 1107 * <p> 1108 * The variable default value delimiter is the character or characters that delimit the 1109 * variable name and the variable default value. This delimiter is expressed in terms of a matcher 1110 * allowing advanced variable default value delimiter matches. 1111 * <p> 1112 * If the {@code valueDelimiterMatcher} is null, then the variable default value resolution 1113 * becomes disabled. 1114 * 1115 * @param valueDelimiterMatcher variable default value delimiter matcher to use, may be null 1116 * @return this, to enable chaining 1117 * @since 3.2 1118 */ 1119 public StrSubstitutor setValueDelimiterMatcher(final StrMatcher valueDelimiterMatcher) { 1120 this.valueDelimiterMatcher = valueDelimiterMatcher; 1121 return this; 1122 } 1123 1124 /** 1125 * Sets the variable default value delimiter to use. 1126 * <p> 1127 * The variable default value delimiter is the character or characters that delimit the 1128 * variable name and the variable default value. This method allows a single character 1129 * variable default value delimiter to be easily set. 1130 * 1131 * @param valueDelimiter the variable default value delimiter character to use 1132 * @return this, to enable chaining 1133 * @since 3.2 1134 */ 1135 public StrSubstitutor setValueDelimiter(final char valueDelimiter) { 1136 return setValueDelimiterMatcher(StrMatcher.charMatcher(valueDelimiter)); 1137 } 1138 1139 /** 1140 * Sets the variable default value delimiter to use. 1141 * <p> 1142 * The variable default value delimiter is the character or characters that delimit the 1143 * variable name and the variable default value. This method allows a string 1144 * variable default value delimiter to be easily set. 1145 * <p> 1146 * If the {@code valueDelimiter} is null or empty string, then the variable default 1147 * value resolution becomes disabled. 1148 * 1149 * @param valueDelimiter the variable default value delimiter string to use, may be null or empty 1150 * @return this, to enable chaining 1151 * @since 3.2 1152 */ 1153 public StrSubstitutor setValueDelimiter(final String valueDelimiter) { 1154 if (StringUtils.isEmpty(valueDelimiter)) { 1155 setValueDelimiterMatcher(null); 1156 return this; 1157 } 1158 return setValueDelimiterMatcher(StrMatcher.stringMatcher(valueDelimiter)); 1159 } 1160 1161 // Resolver 1162 //----------------------------------------------------------------------- 1163 /** 1164 * Gets the VariableResolver that is used to lookup variables. 1165 * 1166 * @return the VariableResolver 1167 */ 1168 public StrLookup<?> getVariableResolver() { 1169 return this.variableResolver; 1170 } 1171 1172 /** 1173 * Sets the VariableResolver that is used to lookup variables. 1174 * 1175 * @param variableResolver the VariableResolver 1176 */ 1177 public void setVariableResolver(final StrLookup<?> variableResolver) { 1178 this.variableResolver = variableResolver; 1179 } 1180 1181 // Substitution support in variable names 1182 //----------------------------------------------------------------------- 1183 /** 1184 * Returns a flag whether substitution is done in variable names. 1185 * 1186 * @return the substitution in variable names flag 1187 * @since 3.0 1188 */ 1189 public boolean isEnableSubstitutionInVariables() { 1190 return enableSubstitutionInVariables; 1191 } 1192 1193 /** 1194 * Sets a flag whether substitution is done in variable names. If set to 1195 * <b>true</b>, the names of variables can contain other variables which are 1196 * processed first before the original variable is evaluated, e.g. 1197 * {@code ${jre-${java.version}}}. The default value is <b>false</b>. 1198 * 1199 * @param enableSubstitutionInVariables the new value of the flag 1200 * @since 3.0 1201 */ 1202 public void setEnableSubstitutionInVariables( 1203 final boolean enableSubstitutionInVariables) { 1204 this.enableSubstitutionInVariables = enableSubstitutionInVariables; 1205 } 1206 1207 /** 1208 * Returns the flag controlling whether escapes are preserved during 1209 * substitution. 1210 * 1211 * @return the preserve escape flag 1212 * @since 3.5 1213 */ 1214 public boolean isPreserveEscapes() { 1215 return preserveEscapes; 1216 } 1217 1218 /** 1219 * Sets a flag controlling whether escapes are preserved during 1220 * substitution. If set to <b>true</b>, the escape character is retained 1221 * during substitution (e.g. {@code $${this-is-escaped}} remains 1222 * {@code $${this-is-escaped}}). If set to <b>false</b>, the escape 1223 * character is removed during substitution (e.g. 1224 * {@code $${this-is-escaped}} becomes 1225 * {@code ${this-is-escaped}}). The default value is <b>false</b> 1226 * 1227 * @param preserveEscapes true if escapes are to be preserved 1228 * @since 3.5 1229 */ 1230 public void setPreserveEscapes(final boolean preserveEscapes) { 1231 this.preserveEscapes = preserveEscapes; 1232 } 1233}