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.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.Objects; 025import java.util.Properties; 026 027import org.apache.commons.lang3.Validate; 028import org.apache.commons.text.lookup.StringLookup; 029import org.apache.commons.text.lookup.StringLookupFactory; 030import org.apache.commons.text.matcher.StringMatcher; 031import org.apache.commons.text.matcher.StringMatcherFactory; 032 033/** 034 * Substitutes variables within a string by values. 035 * <p> 036 * This class takes a piece of text and substitutes all the variables within it. The default definition of a variable is 037 * {@code ${variableName}}. The prefix and suffix can be changed via constructors and set methods. 038 * </p> 039 * <p> 040 * Variable values are typically resolved from a map, but could also be resolved from system properties, or by supplying 041 * a custom variable resolver. 042 * </p> 043 * <h2>Using System Properties</h2> 044 * <p> 045 * The simplest example is to use this class to replace Java System properties. For example: 046 * </p> 047 * 048 * <pre> 049 * StringSubstitutor 050 * .replaceSystemProperties("You are running with java.version = ${java.version} and os.name = ${os.name}."); 051 * </pre> 052 * 053 * <h2>Using a Custom Map</h2> 054 * <p> 055 * Typical usage of this class follows the following pattern: 056 * </p> 057 * <ul> 058 * <li>Create and initialize a StringSubstitutor with the map that contains the values for the variables you want to 059 * make available.</li> 060 * <li>Optionally set attributes like variable prefix, variable suffix, default value delimiter, and so on.</li> 061 * <li>Call the {@code replace()} method with in the source text for interpolation.</li> 062 * <li>The returned text contains all variable references (as long as their values are known) as resolved.</li> 063 * </ul> 064 * <p> 065 * For example: 066 * </p> 067 * 068 * <pre> 069 * // Build map 070 * Map<String, String> valuesMap = new HashMap<>(); 071 * valuesMap.put("animal", "quick brown fox"); 072 * valuesMap.put("target", "lazy dog"); 073 * String templateString = "The ${animal} jumped over the ${target}."; 074 * 075 * // Build StringSubstitutor 076 * StringSubstitutor sub = new StringSubstitutor(valuesMap); 077 * 078 * // Replace 079 * String resolvedString = sub.replace(templateString); 080 * </pre> 081 * 082 * <p> 083 * yielding: 084 * </p> 085 * 086 * <pre> 087 * "The quick brown fox jumped over the lazy dog." 088 * </pre> 089 * 090 * <h2>Providing Default Values</h2> 091 * <p> 092 * You can set a default value for unresolved variables. The default value for a variable can be appended to the 093 * variable name after the variable default value delimiter. The default value of the variable default value delimiter 094 * is ":-", as in bash and other *nix shells. 095 * </p> 096 * <p> 097 * You can set the variable value delimiter with {@link #setValueDelimiterMatcher(StringMatcher)}, 098 * {@link #setValueDelimiter(char)} or {@link #setValueDelimiter(String)}. 099 * </p> 100 * <p> 101 * For example: 102 * </p> 103 * 104 * <pre> 105 * // Build map 106 * Map<String, String> valuesMap = new HashMap<>(); 107 * valuesMap.put("animal", "quick brown fox"); 108 * valuesMap.put("target", "lazy dog"); 109 * String templateString = "The ${animal} jumped over the ${target} ${undefined.number:-1234567890} times."; 110 * 111 * // Build StringSubstitutor 112 * StringSubstitutor sub = new StringSubstitutor(valuesMap); 113 * 114 * // Replace 115 * String resolvedString = sub.replace(templateString); 116 * </pre> 117 * 118 * <p> 119 * yielding: 120 * </p> 121 * 122 * <pre> 123 * "The quick brown fox jumped over the lazy dog 1234567890 times." 124 * </pre> 125 * 126 * <p> 127 * {@code StringSubstitutor} supports throwing exceptions for unresolved variables, you enable this by setting calling 128 * {@link #setEnableUndefinedVariableException(boolean)} with {@code true}. 129 * </p> 130 * 131 * <h2>Reusing Instances</h2> 132 * <p> 133 * Static shortcut methods cover the most common use cases. If multiple replace operations are to be performed, creating 134 * and reusing an instance of this class will be more efficient. 135 * </p> 136 * 137 * <h2>Using Interpolation</h2> 138 * <p> 139 * The default interpolator let's you use string lookups like: 140 * </p> 141 * 142 * <pre> 143 * final StringSubstitutor interpolator = StringSubstitutor.createInterpolator(); 144 * interpolator.setEnableSubstitutionInVariables(true); // Allows for nested $'s. 145 * final String text = interpolator.replace("Base64 Decoder: ${base64Decoder:SGVsbG9Xb3JsZCE=}\n" 146 * + "Base64 Encoder: ${base64Encoder:HelloWorld!}\n" 147 * + "Java Constant: ${const:java.awt.event.KeyEvent.VK_ESCAPE}\n" 148 * + "Date: ${date:yyyy-MM-dd}\n" + "DNS: ${dns:address|apache.org}\n" 149 * + "Environment Variable: ${env:USERNAME}\n" 150 * + "File Content: ${file:UTF-8:src/test/resources/document.properties}\n" 151 * + "Java: ${java:version}\n" + "Localhost: ${localhost:canonical-name}\n" 152 * + "Properties File: ${properties:src/test/resources/document.properties::mykey}\n" 153 * + "Resource Bundle: ${resourceBundle:org.example.testResourceBundleLookup:mykey}\n" 154 * + "Script: ${script:javascript:3 + 4}\n" + "System Property: ${sys:user.dir}\n" 155 * + "URL Decoder: ${urlDecoder:Hello%20World%21}\n" 156 * + "URL Encoder: ${urlEncoder:Hello World!}\n" 157 * + "URL Content (HTTP): ${url:UTF-8:http://www.apache.org}\n" 158 * + "URL Content (HTTPS): ${url:UTF-8:https://www.apache.org}\n" 159 * + "URL Content (File): ${url:UTF-8:file:///${sys:user.dir}/src/test/resources/document.properties}\n" 160 * + "XML XPath: ${xml:src/test/resources/document.xml:/root/path/to/node}\n"); 161 * </pre> 162 * <p> 163 * For documentation of each lookup, see {@link StringLookupFactory}. 164 * </p> 165 * 166 * <h2>Using Recursive Variable Replacement</h2> 167 * <p> 168 * Variable replacement can work recursively by calling {@link #setEnableSubstitutionInVariables(boolean)} with 169 * {@code true}. If a variable value contains a variable then that variable will also be replaced. Cyclic replacements 170 * are detected and will throw an exception. 171 * </p> 172 * <p> 173 * You can get the replace result to contain a variable prefix. For example: 174 * </p> 175 * 176 * <pre> 177 * "The variable ${${name}} must be used." 178 * </pre> 179 * 180 * <p> 181 * If the value of the "name" variable is "x", then only the variable "name" is replaced resulting in: 182 * </p> 183 * 184 * <pre> 185 * "The variable ${x} must be used." 186 * </pre> 187 * 188 * <p> 189 * To achieve this effect there are two possibilities: Either set a different prefix and suffix for variables which do 190 * not conflict with the result text you want to produce. The other possibility is to use the escape character, by 191 * default '$'. If this character is placed before a variable reference, this reference is ignored and won't be 192 * replaced. For example: 193 * </p> 194 * 195 * <pre> 196 * "The variable $${${name}} must be used." 197 * </pre> 198 * <p> 199 * In some complex scenarios you might even want to perform substitution in the names of variables, for instance 200 * </p> 201 * 202 * <pre> 203 * ${jre-${java.specification.version}} 204 * </pre> 205 * 206 * <p> 207 * {@code StringSubstitutor} supports this recursive substitution in variable names, but it has to be enabled explicitly 208 * by calling {@link #setEnableSubstitutionInVariables(boolean)} with {@code true}. 209 * </p> 210 * 211 * <h2>Thread Safety</h2> 212 * <p> 213 * This class is <b>not</b> thread safe. 214 * </p> 215 * 216 * @since 1.3 217 */ 218public class StringSubstitutor { 219 220 /** 221 * The low-level result of a substitution. 222 * 223 * @since 1.9 224 */ 225 private static final class Result { 226 227 /** Whether the buffer is altered. */ 228 public final boolean altered; 229 230 /** The length of change. */ 231 public final int lengthChange; 232 233 private Result(final boolean altered, final int lengthChange) { 234 super(); 235 this.altered = altered; 236 this.lengthChange = lengthChange; 237 } 238 239 @Override 240 public String toString() { 241 return "Result [altered=" + altered + ", lengthChange=" + lengthChange + "]"; 242 } 243 } 244 245 /** 246 * Constant for the default escape character. 247 */ 248 public static final char DEFAULT_ESCAPE = '$'; 249 250 /** 251 * The default variable default separator. 252 * 253 * @since 1.5. 254 */ 255 public static final String DEFAULT_VAR_DEFAULT = ":-"; 256 257 /** 258 * The default variable end separator. 259 * 260 * @since 1.5. 261 */ 262 public static final String DEFAULT_VAR_END = "}"; 263 264 /** 265 * The default variable start separator. 266 * 267 * @since 1.5. 268 */ 269 public static final String DEFAULT_VAR_START = "${"; 270 271 /** 272 * Constant for the default variable prefix. 273 */ 274 public static final StringMatcher DEFAULT_PREFIX = StringMatcherFactory.INSTANCE.stringMatcher(DEFAULT_VAR_START); 275 276 /** 277 * Constant for the default variable suffix. 278 */ 279 public static final StringMatcher DEFAULT_SUFFIX = StringMatcherFactory.INSTANCE.stringMatcher(DEFAULT_VAR_END); 280 281 /** 282 * Constant for the default value delimiter of a variable. 283 */ 284 public static final StringMatcher DEFAULT_VALUE_DELIMITER = StringMatcherFactory.INSTANCE 285 .stringMatcher(DEFAULT_VAR_DEFAULT); 286 287 /** 288 * Creates a new instance using the interpolator string lookup 289 * {@link StringLookupFactory#interpolatorStringLookup()}. 290 * <p> 291 * This StringSubstitutor lets you perform substituions like: 292 * </p> 293 * 294 * <pre> 295 * StringSubstitutor.createInterpolator().replace( 296 * "OS name: ${sys:os.name}, " + "3 + 4 = ${script:javascript:3 + 4}"); 297 * </pre> 298 * 299 * @return a new instance using the interpolator string lookup. 300 * @see StringLookupFactory#interpolatorStringLookup() 301 * @since 1.8 302 */ 303 public static StringSubstitutor createInterpolator() { 304 return new StringSubstitutor(StringLookupFactory.INSTANCE.interpolatorStringLookup()); 305 } 306 307 /** 308 * Replaces all the occurrences of variables in the given source object with their matching values from the map. 309 * 310 * @param <V> the type of the values in the map 311 * @param source the source text containing the variables to substitute, null returns null 312 * @param valueMap the map with the values, may be null 313 * @return The result of the replace operation 314 * @throws IllegalArgumentException if a variable is not found and enableUndefinedVariableException is true 315 */ 316 public static <V> String replace(final Object source, final Map<String, V> valueMap) { 317 return new StringSubstitutor(valueMap).replace(source); 318 } 319 320 /** 321 * Replaces all the occurrences of variables in the given source object with their matching values from the map. 322 * This method allows to specify a custom variable prefix and suffix 323 * 324 * @param <V> the type of the values in the map 325 * @param source the source text containing the variables to substitute, null returns null 326 * @param valueMap the map with the values, may be null 327 * @param prefix the prefix of variables, not null 328 * @param suffix the suffix of variables, not null 329 * @return The result of the replace operation 330 * @throws IllegalArgumentException if the prefix or suffix is null 331 * @throws IllegalArgumentException if a variable is not found and enableUndefinedVariableException is true 332 */ 333 public static <V> String replace(final Object source, final Map<String, V> valueMap, final String prefix, 334 final String suffix) { 335 return new StringSubstitutor(valueMap, prefix, suffix).replace(source); 336 } 337 338 /** 339 * Replaces all the occurrences of variables in the given source object with their matching values from the 340 * properties. 341 * 342 * @param source the source text containing the variables to substitute, null returns null 343 * @param valueProperties the properties with values, may be null 344 * @return The result of the replace operation 345 * @throws IllegalArgumentException if a variable is not found and enableUndefinedVariableException is true 346 */ 347 public static String replace(final Object source, final Properties valueProperties) { 348 if (valueProperties == null) { 349 return source.toString(); 350 } 351 final Map<String, String> valueMap = new HashMap<>(); 352 final Enumeration<?> propNames = valueProperties.propertyNames(); 353 while (propNames.hasMoreElements()) { 354 final String propName = (String) propNames.nextElement(); 355 final String propValue = valueProperties.getProperty(propName); 356 valueMap.put(propName, propValue); 357 } 358 return StringSubstitutor.replace(source, valueMap); 359 } 360 361 /** 362 * Replaces all the occurrences of variables in the given source object with their matching values from the system 363 * properties. 364 * 365 * @param source the source text containing the variables to substitute, null returns null 366 * @return The result of the replace operation 367 * @throws IllegalArgumentException if a variable is not found and enableUndefinedVariableException is true 368 */ 369 public static String replaceSystemProperties(final Object source) { 370 return new StringSubstitutor(StringLookupFactory.INSTANCE.systemPropertyStringLookup()).replace(source); 371 } 372 373 /** 374 * The flag whether substitution in variable values is disabled. 375 */ 376 private boolean disableSubstitutionInValues; 377 378 /** 379 * The flag whether substitution in variable names is enabled. 380 */ 381 private boolean enableSubstitutionInVariables; 382 383 /** 384 * The flag whether exception should be thrown on undefined variable. 385 */ 386 private boolean enableUndefinedVariableException; 387 388 /** 389 * Stores the escape character. 390 */ 391 private char escapeChar; 392 393 /** 394 * Stores the variable prefix. 395 */ 396 private StringMatcher prefixMatcher; 397 398 /** 399 * Whether escapes should be preserved. Default is false; 400 */ 401 private boolean preserveEscapes; 402 403 /** 404 * Stores the variable suffix. 405 */ 406 private StringMatcher suffixMatcher; 407 408 /** 409 * Stores the default variable value delimiter. 410 */ 411 private StringMatcher valueDelimiterMatcher; 412 413 /** 414 * Variable resolution is delegated to an implementor of {@link StringLookup}. 415 */ 416 private StringLookup variableResolver; 417 418 /** 419 * Creates a new instance with defaults for variable prefix and suffix and the escaping character. 420 */ 421 public StringSubstitutor() { 422 this((StringLookup) null, DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE); 423 } 424 425 /** 426 * Creates a new instance and initializes it. Uses defaults for variable prefix and suffix and the escaping 427 * character. 428 * 429 * @param <V> the type of the values in the map 430 * @param valueMap the map with the variables' values, may be null 431 */ 432 public <V> StringSubstitutor(final Map<String, V> valueMap) { 433 this(StringLookupFactory.INSTANCE.mapStringLookup(valueMap), DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE); 434 } 435 436 /** 437 * Creates a new instance and initializes it. Uses a default escaping character. 438 * 439 * @param <V> the type of the values in the map 440 * @param valueMap the map with the variables' values, may be null 441 * @param prefix the prefix for variables, not null 442 * @param suffix the suffix for variables, not null 443 * @throws IllegalArgumentException if the prefix or suffix is null 444 */ 445 public <V> StringSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix) { 446 this(StringLookupFactory.INSTANCE.mapStringLookup(valueMap), prefix, suffix, DEFAULT_ESCAPE); 447 } 448 449 /** 450 * Creates a new instance and initializes it. 451 * 452 * @param <V> the type of the values in the map 453 * @param valueMap the map with the variables' values, may be null 454 * @param prefix the prefix for variables, not null 455 * @param suffix the suffix for variables, not null 456 * @param escape the escape character 457 * @throws IllegalArgumentException if the prefix or suffix is null 458 */ 459 public <V> StringSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix, 460 final char escape) { 461 this(StringLookupFactory.INSTANCE.mapStringLookup(valueMap), prefix, suffix, escape); 462 } 463 464 /** 465 * Creates a new instance and initializes it. 466 * 467 * @param <V> the type of the values in the map 468 * @param valueMap the map with the variables' values, may be null 469 * @param prefix the prefix for variables, not null 470 * @param suffix the suffix for variables, not null 471 * @param escape the escape character 472 * @param valueDelimiter the variable default value delimiter, may be null 473 * @throws IllegalArgumentException if the prefix or suffix is null 474 */ 475 public <V> StringSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix, 476 final char escape, final String valueDelimiter) { 477 this(StringLookupFactory.INSTANCE.mapStringLookup(valueMap), prefix, suffix, escape, valueDelimiter); 478 } 479 480 /** 481 * Creates a new instance and initializes it. 482 * 483 * @param variableResolver the variable resolver, may be null 484 */ 485 public StringSubstitutor(final StringLookup variableResolver) { 486 this(variableResolver, DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE); 487 } 488 489 /** 490 * Creates a new instance and initializes it. 491 * 492 * @param variableResolver the variable resolver, may be null 493 * @param prefix the prefix for variables, not null 494 * @param suffix the suffix for variables, not null 495 * @param escape the escape character 496 * @throws IllegalArgumentException if the prefix or suffix is null 497 */ 498 public StringSubstitutor(final StringLookup variableResolver, final String prefix, final String suffix, 499 final char escape) { 500 this.setVariableResolver(variableResolver); 501 this.setVariablePrefix(prefix); 502 this.setVariableSuffix(suffix); 503 this.setEscapeChar(escape); 504 this.setValueDelimiterMatcher(DEFAULT_VALUE_DELIMITER); 505 } 506 507 /** 508 * Creates a new instance and initializes it. 509 * 510 * @param variableResolver the variable resolver, may be null 511 * @param prefix the prefix for variables, not null 512 * @param suffix the suffix for variables, not null 513 * @param escape the escape character 514 * @param valueDelimiter the variable default value delimiter string, may be null 515 * @throws IllegalArgumentException if the prefix or suffix is null 516 */ 517 public StringSubstitutor(final StringLookup variableResolver, final String prefix, final String suffix, 518 final char escape, final String valueDelimiter) { 519 this.setVariableResolver(variableResolver); 520 this.setVariablePrefix(prefix); 521 this.setVariableSuffix(suffix); 522 this.setEscapeChar(escape); 523 this.setValueDelimiter(valueDelimiter); 524 } 525 526 /** 527 * Creates a new instance and initializes it. 528 * 529 * @param variableResolver the variable resolver, may be null 530 * @param prefixMatcher the prefix for variables, not null 531 * @param suffixMatcher the suffix for variables, not null 532 * @param escape the escape character 533 * @throws IllegalArgumentException if the prefix or suffix is null 534 */ 535 public StringSubstitutor(final StringLookup variableResolver, final StringMatcher prefixMatcher, 536 final StringMatcher suffixMatcher, final char escape) { 537 this(variableResolver, prefixMatcher, suffixMatcher, escape, DEFAULT_VALUE_DELIMITER); 538 } 539 540 /** 541 * Creates a new instance and initializes it. 542 * 543 * @param variableResolver the variable resolver, may be null 544 * @param prefixMatcher the prefix for variables, not null 545 * @param suffixMatcher the suffix for variables, not null 546 * @param escape the escape character 547 * @param valueDelimiterMatcher the variable default value delimiter matcher, may be null 548 * @throws IllegalArgumentException if the prefix or suffix is null 549 */ 550 public StringSubstitutor(final StringLookup variableResolver, final StringMatcher prefixMatcher, 551 final StringMatcher suffixMatcher, final char escape, final StringMatcher valueDelimiterMatcher) { 552 this.setVariableResolver(variableResolver); 553 this.setVariablePrefixMatcher(prefixMatcher); 554 this.setVariableSuffixMatcher(suffixMatcher); 555 this.setEscapeChar(escape); 556 this.setValueDelimiterMatcher(valueDelimiterMatcher); 557 } 558 559 /** 560 * Creates a new instance based on the given StringSubstitutor. 561 * 562 * @param other The StringSubstitutor is use as the source. 563 * @since 1.9 564 */ 565 public StringSubstitutor(final StringSubstitutor other) { 566 disableSubstitutionInValues = other.isDisableSubstitutionInValues(); 567 enableSubstitutionInVariables = other.isEnableSubstitutionInVariables(); 568 enableUndefinedVariableException = other.isEnableUndefinedVariableException(); 569 escapeChar = other.getEscapeChar(); 570 prefixMatcher = other.getVariablePrefixMatcher(); 571 preserveEscapes = other.isPreserveEscapes(); 572 suffixMatcher = other.getVariableSuffixMatcher(); 573 valueDelimiterMatcher = other.getValueDelimiterMatcher(); 574 variableResolver = other.getStringLookup(); 575 } 576 577 /** 578 * Checks if the specified variable is already in the stack (list) of variables. 579 * 580 * @param varName the variable name to check 581 * @param priorVariables the list of prior variables 582 */ 583 private void checkCyclicSubstitution(final String varName, final List<String> priorVariables) { 584 if (!priorVariables.contains(varName)) { 585 return; 586 } 587 final TextStringBuilder buf = new TextStringBuilder(256); 588 buf.append("Infinite loop in property interpolation of "); 589 buf.append(priorVariables.remove(0)); 590 buf.append(": "); 591 buf.appendWithSeparators(priorVariables, "->"); 592 throw new IllegalStateException(buf.toString()); 593 } 594 595 // Escape 596 /** 597 * Returns the escape character. 598 * 599 * @return The character used for escaping variable references 600 */ 601 public char getEscapeChar() { 602 return this.escapeChar; 603 } 604 605 /** 606 * Gets the StringLookup that is used to lookup variables. 607 * 608 * @return The StringLookup 609 */ 610 public StringLookup getStringLookup() { 611 return this.variableResolver; 612 } 613 614 /** 615 * Gets the variable default value delimiter matcher currently in use. 616 * <p> 617 * The variable default value delimiter is the character or characters that delimit the variable name and the 618 * variable default value. This delimiter is expressed in terms of a matcher allowing advanced variable default 619 * value delimiter matches. 620 * </p> 621 * <p> 622 * If it returns null, then the variable default value resolution is disabled. 623 * 624 * @return The variable default value delimiter matcher in use, may be null 625 */ 626 public StringMatcher getValueDelimiterMatcher() { 627 return valueDelimiterMatcher; 628 } 629 630 /** 631 * Gets the variable prefix matcher currently in use. 632 * <p> 633 * The variable prefix is the character or characters that identify the start of a variable. This prefix is 634 * expressed in terms of a matcher allowing advanced prefix matches. 635 * </p> 636 * 637 * @return The prefix matcher in use 638 */ 639 public StringMatcher getVariablePrefixMatcher() { 640 return prefixMatcher; 641 } 642 643 /** 644 * Gets the variable suffix matcher currently in use. 645 * <p> 646 * The variable suffix is the character or characters that identify the end of a variable. This suffix is expressed 647 * in terms of a matcher allowing advanced suffix matches. 648 * </p> 649 * 650 * @return The suffix matcher in use 651 */ 652 public StringMatcher getVariableSuffixMatcher() { 653 return suffixMatcher; 654 } 655 656 /** 657 * Returns a flag whether substitution is disabled in variable values.If set to <b>true</b>, the values of variables 658 * can contain other variables will not be processed and substituted original variable is evaluated, e.g. 659 * 660 * <pre> 661 * Map<String, String> valuesMap = new HashMap<>(); 662 * valuesMap.put("name", "Douglas ${surname}"); 663 * valuesMap.put("surname", "Crockford"); 664 * String templateString = "Hi ${name}"; 665 * StrSubstitutor sub = new StrSubstitutor(valuesMap); 666 * String resolvedString = sub.replace(templateString); 667 * </pre> 668 * 669 * yielding: 670 * 671 * <pre> 672 * Hi Douglas ${surname} 673 * </pre> 674 * 675 * @return The substitution in variable values flag 676 */ 677 public boolean isDisableSubstitutionInValues() { 678 return disableSubstitutionInValues; 679 } 680 681 /** 682 * Returns a flag whether substitution is done in variable names. 683 * 684 * @return The substitution in variable names flag 685 */ 686 public boolean isEnableSubstitutionInVariables() { 687 return enableSubstitutionInVariables; 688 } 689 690 /** 691 * Returns a flag whether exception can be thrown upon undefined variable. 692 * 693 * @return The fail on undefined variable flag 694 */ 695 public boolean isEnableUndefinedVariableException() { 696 return enableUndefinedVariableException; 697 } 698 699 /** 700 * Returns the flag controlling whether escapes are preserved during substitution. 701 * 702 * @return The preserve escape flag 703 */ 704 public boolean isPreserveEscapes() { 705 return preserveEscapes; 706 } 707 708 /** 709 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 710 * array as a template. The array is not altered by this method. 711 * 712 * @param source the character array to replace in, not altered, null returns null 713 * @return The result of the replace operation 714 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 715 */ 716 public String replace(final char[] source) { 717 if (source == null) { 718 return null; 719 } 720 final TextStringBuilder buf = new TextStringBuilder(source.length).append(source); 721 substitute(buf, 0, source.length); 722 return buf.toString(); 723 } 724 725 /** 726 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 727 * array as a template. The array is not altered by this method. 728 * <p> 729 * Only the specified portion of the array will be processed. The rest of the array is not processed, and is not 730 * returned. 731 * </p> 732 * 733 * @param source the character array to replace in, not altered, null returns null 734 * @param offset the start offset within the array, must be valid 735 * @param length the length within the array to be processed, must be valid 736 * @return The result of the replace operation 737 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 738 */ 739 public String replace(final char[] source, final int offset, final int length) { 740 if (source == null) { 741 return null; 742 } 743 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 744 substitute(buf, 0, length); 745 return buf.toString(); 746 } 747 748 /** 749 * Replaces all the occurrences of variables with their matching values from the resolver using the given source as 750 * a template. The source is not altered by this method. 751 * 752 * @param source the buffer to use as a template, not changed, null returns null 753 * @return The result of the replace operation 754 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 755 */ 756 public String replace(final CharSequence source) { 757 if (source == null) { 758 return null; 759 } 760 return replace(source, 0, source.length()); 761 } 762 763 /** 764 * Replaces all the occurrences of variables with their matching values from the resolver using the given source as 765 * a template. The source is not altered by this method. 766 * <p> 767 * Only the specified portion of the buffer will be processed. The rest of the buffer is not processed, and is not 768 * returned. 769 * </p> 770 * 771 * @param source the buffer to use as a template, not changed, null returns null 772 * @param offset the start offset within the array, must be valid 773 * @param length the length within the array to be processed, must be valid 774 * @return The result of the replace operation 775 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 776 */ 777 public String replace(final CharSequence source, final int offset, final int length) { 778 if (source == null) { 779 return null; 780 } 781 final TextStringBuilder buf = new TextStringBuilder(length).append(source.toString(), offset, length); 782 substitute(buf, 0, length); 783 return buf.toString(); 784 } 785 786 /** 787 * Replaces all the occurrences of variables in the given source object with their matching values from the 788 * resolver. The input source object is converted to a string using {@code toString} and is not altered. 789 * 790 * @param source the source to replace in, null returns null 791 * @return The result of the replace operation 792 * @throws IllegalArgumentException if a variable is not found and enableUndefinedVariableException is true 793 */ 794 public String replace(final Object source) { 795 if (source == null) { 796 return null; 797 } 798 final TextStringBuilder buf = new TextStringBuilder().append(source); 799 substitute(buf, 0, buf.length()); 800 return buf.toString(); 801 } 802 803 /** 804 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 805 * string as a template. 806 * 807 * @param source the string to replace in, null returns null 808 * @return The result of the replace operation 809 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 810 */ 811 public String replace(final String source) { 812 if (source == null) { 813 return null; 814 } 815 final TextStringBuilder buf = new TextStringBuilder(source); 816 if (!substitute(buf, 0, source.length())) { 817 return source; 818 } 819 return buf.toString(); 820 } 821 822 /** 823 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 824 * string as a template. 825 * <p> 826 * Only the specified portion of the string will be processed. The rest of the string is not processed, and is not 827 * returned. 828 * </p> 829 * 830 * @param source the string to replace in, null returns null 831 * @param offset the start offset within the source, must be valid 832 * @param length the length within the source to be processed, must be valid 833 * @return The result of the replace operation 834 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 835 */ 836 public String replace(final String source, final int offset, final int length) { 837 if (source == null) { 838 return null; 839 } 840 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 841 if (!substitute(buf, 0, length)) { 842 return source.substring(offset, offset + length); 843 } 844 return buf.toString(); 845 } 846 847 /** 848 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 849 * buffer as a template. The buffer is not altered by this method. 850 * 851 * @param source the buffer to use as a template, not changed, null returns null 852 * @return The result of the replace operation 853 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 854 */ 855 public String replace(final StringBuffer source) { 856 if (source == null) { 857 return null; 858 } 859 final TextStringBuilder buf = new TextStringBuilder(source.length()).append(source); 860 substitute(buf, 0, buf.length()); 861 return buf.toString(); 862 } 863 864 /** 865 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 866 * buffer as a template. The buffer is not altered by this method. 867 * <p> 868 * Only the specified portion of the buffer will be processed. The rest of the buffer is not processed, and is not 869 * returned. 870 * </p> 871 * 872 * @param source the buffer to use as a template, not changed, null returns null 873 * @param offset the start offset within the source, must be valid 874 * @param length the length within the source to be processed, must be valid 875 * @return The result of the replace operation 876 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 877 */ 878 public String replace(final StringBuffer source, final int offset, final int length) { 879 if (source == null) { 880 return null; 881 } 882 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 883 substitute(buf, 0, length); 884 return buf.toString(); 885 } 886 887 /** 888 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 889 * builder as a template. The builder is not altered by this method. 890 * 891 * @param source the builder to use as a template, not changed, null returns null 892 * @return The result of the replace operation 893 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 894 */ 895 public String replace(final TextStringBuilder source) { 896 if (source == null) { 897 return null; 898 } 899 final TextStringBuilder builder = new TextStringBuilder(source.length()).append(source); 900 substitute(builder, 0, builder.length()); 901 return builder.toString(); 902 } 903 904 /** 905 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 906 * builder as a template. The builder is not altered by this method. 907 * <p> 908 * Only the specified portion of the builder will be processed. The rest of the builder is not processed, and is not 909 * returned. 910 * </p> 911 * 912 * @param source the builder to use as a template, not changed, null returns null 913 * @param offset the start offset within the source, must be valid 914 * @param length the length within the source to be processed, must be valid 915 * @return The result of the replace operation 916 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 917 */ 918 public String replace(final TextStringBuilder source, final int offset, final int length) { 919 if (source == null) { 920 return null; 921 } 922 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 923 substitute(buf, 0, length); 924 return buf.toString(); 925 } 926 927 /** 928 * Replaces all the occurrences of variables within the given source buffer with their matching values from the 929 * resolver. The buffer is updated with the result. 930 * 931 * @param source the buffer to replace in, updated, null returns zero 932 * @return true if altered 933 */ 934 public boolean replaceIn(final StringBuffer source) { 935 if (source == null) { 936 return false; 937 } 938 return replaceIn(source, 0, source.length()); 939 } 940 941 /** 942 * Replaces all the occurrences of variables within the given source buffer with their matching values from the 943 * resolver. The buffer is updated with the result. 944 * <p> 945 * Only the specified portion of the buffer will be processed. The rest of the buffer is not processed, but it is 946 * not deleted. 947 * </p> 948 * 949 * @param source the buffer to replace in, updated, null returns zero 950 * @param offset the start offset within the source, must be valid 951 * @param length the length within the source to be processed, must be valid 952 * @return true if altered 953 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 954 */ 955 public boolean replaceIn(final StringBuffer source, final int offset, final int length) { 956 if (source == null) { 957 return false; 958 } 959 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 960 if (!substitute(buf, 0, length)) { 961 return false; 962 } 963 source.replace(offset, offset + length, buf.toString()); 964 return true; 965 } 966 967 /** 968 * Replaces all the occurrences of variables within the given source buffer with their matching values from the 969 * resolver. The buffer is updated with the result. 970 * 971 * @param source the buffer to replace in, updated, null returns zero 972 * @return true if altered 973 */ 974 public boolean replaceIn(final StringBuilder source) { 975 if (source == null) { 976 return false; 977 } 978 return replaceIn(source, 0, source.length()); 979 } 980 981 /** 982 * Replaces all the occurrences of variables within the given source builder with their matching values from the 983 * resolver. The builder is updated with the result. 984 * <p> 985 * Only the specified portion of the buffer will be processed. The rest of the buffer is not processed, but it is 986 * not deleted. 987 * </p> 988 * 989 * @param source the buffer to replace in, updated, null returns zero 990 * @param offset the start offset within the source, must be valid 991 * @param length the length within the source to be processed, must be valid 992 * @return true if altered 993 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 994 */ 995 public boolean replaceIn(final StringBuilder source, final int offset, final int length) { 996 if (source == null) { 997 return false; 998 } 999 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 1000 if (!substitute(buf, 0, length)) { 1001 return false; 1002 } 1003 source.replace(offset, offset + length, buf.toString()); 1004 return true; 1005 } 1006 1007 /** 1008 * Replaces all the occurrences of variables within the given source builder with their matching values from the 1009 * resolver. 1010 * 1011 * @param source the builder to replace in, updated, null returns zero 1012 * @return true if altered 1013 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 1014 */ 1015 public boolean replaceIn(final TextStringBuilder source) { 1016 if (source == null) { 1017 return false; 1018 } 1019 return substitute(source, 0, source.length()); 1020 } 1021 1022 /** 1023 * Replaces all the occurrences of variables within the given source builder with their matching values from the 1024 * resolver. 1025 * <p> 1026 * Only the specified portion of the builder will be processed. The rest of the builder is not processed, but it is 1027 * not deleted. 1028 * </p> 1029 * 1030 * @param source the builder to replace in, null returns zero 1031 * @param offset the start offset within the source, must be valid 1032 * @param length the length within the source to be processed, must be valid 1033 * @return true if altered 1034 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 1035 */ 1036 public boolean replaceIn(final TextStringBuilder source, final int offset, final int length) { 1037 if (source == null) { 1038 return false; 1039 } 1040 return substitute(source, offset, length); 1041 } 1042 1043 /** 1044 * Internal method that resolves the value of a variable. 1045 * <p> 1046 * Most users of this class do not need to call this method. This method is called automatically by the substitution 1047 * process. 1048 * </p> 1049 * <p> 1050 * Writers of subclasses can override this method if they need to alter how each substitution occurs. The method is 1051 * passed the variable's name and must return the corresponding value. This implementation uses the 1052 * {@link #getStringLookup()} with the variable's name as the key. 1053 * </p> 1054 * 1055 * @param variableName the name of the variable, not null 1056 * @param buf the buffer where the substitution is occurring, not null 1057 * @param startPos the start position of the variable including the prefix, valid 1058 * @param endPos the end position of the variable including the suffix, valid 1059 * @return The variable's value or <b>null</b> if the variable is unknown 1060 */ 1061 protected String resolveVariable(final String variableName, final TextStringBuilder buf, final int startPos, 1062 final int endPos) { 1063 final StringLookup resolver = getStringLookup(); 1064 if (resolver == null) { 1065 return null; 1066 } 1067 return resolver.lookup(variableName); 1068 } 1069 1070 /** 1071 * Sets a flag whether substitution is done in variable values (recursive). 1072 * 1073 * @param disableSubstitutionInValues true if substitution in variable value are disabled 1074 * @return this, to enable chaining 1075 */ 1076 public StringSubstitutor setDisableSubstitutionInValues(final boolean disableSubstitutionInValues) { 1077 this.disableSubstitutionInValues = disableSubstitutionInValues; 1078 return this; 1079 } 1080 1081 /** 1082 * Sets a flag whether substitution is done in variable names. If set to <b>true</b>, the names of variables can 1083 * contain other variables which are processed first before the original variable is evaluated, e.g. 1084 * {@code ${jre-${java.version}}}. The default value is <b>false</b>. 1085 * 1086 * @param enableSubstitutionInVariables the new value of the flag 1087 * @return this, to enable chaining 1088 */ 1089 public StringSubstitutor setEnableSubstitutionInVariables(final boolean enableSubstitutionInVariables) { 1090 this.enableSubstitutionInVariables = enableSubstitutionInVariables; 1091 return this; 1092 } 1093 1094 /** 1095 * Sets a flag whether exception should be thrown if any variable is undefined. 1096 * 1097 * @param failOnUndefinedVariable true if exception should be thrown on undefined variable 1098 * @return this, to enable chaining 1099 */ 1100 public StringSubstitutor setEnableUndefinedVariableException(final boolean failOnUndefinedVariable) { 1101 this.enableUndefinedVariableException = failOnUndefinedVariable; 1102 return this; 1103 } 1104 1105 /** 1106 * Sets the escape character. If this character is placed before a variable reference in the source text, this 1107 * variable will be ignored. 1108 * 1109 * @param escapeCharacter the escape character (0 for disabling escaping) 1110 * @return this, to enable chaining 1111 */ 1112 public StringSubstitutor setEscapeChar(final char escapeCharacter) { 1113 this.escapeChar = escapeCharacter; 1114 return this; 1115 } 1116 1117 /** 1118 * Sets a flag controlling whether escapes are preserved during substitution. If set to <b>true</b>, the escape 1119 * character is retained during substitution (e.g. {@code $${this-is-escaped}} remains {@code $${this-is-escaped}}). 1120 * If set to <b>false</b>, the escape character is removed during substitution (e.g. {@code $${this-is-escaped}} 1121 * becomes {@code ${this-is-escaped}}). The default value is <b>false</b> 1122 * 1123 * @param preserveEscapes true if escapes are to be preserved 1124 * @return this, to enable chaining 1125 */ 1126 public StringSubstitutor setPreserveEscapes(final boolean preserveEscapes) { 1127 this.preserveEscapes = preserveEscapes; 1128 return this; 1129 } 1130 1131 /** 1132 * Sets the variable default value delimiter to use. 1133 * <p> 1134 * The variable default value delimiter is the character or characters that delimit the variable name and the 1135 * variable default value. This method allows a single character variable default value delimiter to be easily set. 1136 * </p> 1137 * 1138 * @param valueDelimiter the variable default value delimiter character to use 1139 * @return this, to enable chaining 1140 */ 1141 public StringSubstitutor setValueDelimiter(final char valueDelimiter) { 1142 return setValueDelimiterMatcher(StringMatcherFactory.INSTANCE.charMatcher(valueDelimiter)); 1143 } 1144 1145 /** 1146 * Sets the variable default value delimiter to use. 1147 * <p> 1148 * The variable default value delimiter is the character or characters that delimit the variable name and the 1149 * variable default value. This method allows a string variable default value delimiter to be easily set. 1150 * </p> 1151 * <p> 1152 * If the {@code valueDelimiter} is null or empty string, then the variable default value resolution becomes 1153 * disabled. 1154 * </p> 1155 * 1156 * @param valueDelimiter the variable default value delimiter string to use, may be null or empty 1157 * @return this, to enable chaining 1158 */ 1159 public StringSubstitutor setValueDelimiter(final String valueDelimiter) { 1160 if (valueDelimiter == null || valueDelimiter.length() == 0) { 1161 setValueDelimiterMatcher(null); 1162 return this; 1163 } 1164 return setValueDelimiterMatcher(StringMatcherFactory.INSTANCE.stringMatcher(valueDelimiter)); 1165 } 1166 1167 /** 1168 * Sets the variable default value delimiter matcher to use. 1169 * <p> 1170 * The variable default value delimiter is the character or characters that delimit the variable name and the 1171 * variable default value. This delimiter is expressed in terms of a matcher allowing advanced variable default 1172 * value delimiter matches. 1173 * </p> 1174 * <p> 1175 * If the {@code valueDelimiterMatcher} is null, then the variable default value resolution becomes disabled. 1176 * </p> 1177 * 1178 * @param valueDelimiterMatcher variable default value delimiter matcher to use, may be null 1179 * @return this, to enable chaining 1180 */ 1181 public StringSubstitutor setValueDelimiterMatcher(final StringMatcher valueDelimiterMatcher) { 1182 this.valueDelimiterMatcher = valueDelimiterMatcher; 1183 return this; 1184 } 1185 1186 /** 1187 * Sets the variable prefix to use. 1188 * <p> 1189 * The variable prefix is the character or characters that identify the start of a variable. This method allows a 1190 * single character prefix to be easily set. 1191 * </p> 1192 * 1193 * @param prefix the prefix character to use 1194 * @return this, to enable chaining 1195 */ 1196 public StringSubstitutor setVariablePrefix(final char prefix) { 1197 return setVariablePrefixMatcher(StringMatcherFactory.INSTANCE.charMatcher(prefix)); 1198 } 1199 1200 /** 1201 * Sets the variable prefix to use. 1202 * <p> 1203 * The variable prefix is the character or characters that identify the start of a variable. This method allows a 1204 * string prefix to be easily set. 1205 * </p> 1206 * 1207 * @param prefix the prefix for variables, not null 1208 * @return this, to enable chaining 1209 * @throws IllegalArgumentException if the prefix is null 1210 */ 1211 public StringSubstitutor setVariablePrefix(final String prefix) { 1212 Validate.isTrue(prefix != null, "Variable prefix must not be null!"); 1213 return setVariablePrefixMatcher(StringMatcherFactory.INSTANCE.stringMatcher(prefix)); 1214 } 1215 1216 /** 1217 * Sets the variable prefix matcher currently in use. 1218 * <p> 1219 * The variable prefix is the character or characters that identify the start of a variable. This prefix is 1220 * expressed in terms of a matcher allowing advanced prefix matches. 1221 * </p> 1222 * 1223 * @param prefixMatcher the prefix matcher to use, null ignored 1224 * @return this, to enable chaining 1225 * @throws IllegalArgumentException if the prefix matcher is null 1226 */ 1227 public StringSubstitutor setVariablePrefixMatcher(final StringMatcher prefixMatcher) { 1228 Validate.isTrue(prefixMatcher != null, "Variable prefix matcher must not be null!"); 1229 this.prefixMatcher = prefixMatcher; 1230 return this; 1231 } 1232 1233 /** 1234 * Sets the VariableResolver that is used to lookup variables. 1235 * 1236 * @param variableResolver the VariableResolver 1237 * @return this, to enable chaining 1238 */ 1239 public StringSubstitutor setVariableResolver(final StringLookup variableResolver) { 1240 this.variableResolver = variableResolver; 1241 return this; 1242 } 1243 1244 /** 1245 * Sets the variable suffix to use. 1246 * <p> 1247 * The variable suffix is the character or characters that identify the end of a variable. This method allows a 1248 * single character suffix to be easily set. 1249 * </p> 1250 * 1251 * @param suffix the suffix character to use 1252 * @return this, to enable chaining 1253 */ 1254 public StringSubstitutor setVariableSuffix(final char suffix) { 1255 return setVariableSuffixMatcher(StringMatcherFactory.INSTANCE.charMatcher(suffix)); 1256 } 1257 1258 /** 1259 * Sets the variable suffix to use. 1260 * <p> 1261 * The variable suffix is the character or characters that identify the end of a variable. This method allows a 1262 * string suffix to be easily set. 1263 * </p> 1264 * 1265 * @param suffix the suffix for variables, not null 1266 * @return this, to enable chaining 1267 * @throws IllegalArgumentException if the suffix is null 1268 */ 1269 public StringSubstitutor setVariableSuffix(final String suffix) { 1270 Validate.isTrue(suffix != null, "Variable suffix must not be null!"); 1271 return setVariableSuffixMatcher(StringMatcherFactory.INSTANCE.stringMatcher(suffix)); 1272 } 1273 1274 /** 1275 * Sets the variable suffix matcher currently in use. 1276 * <p> 1277 * The variable suffix is the character or characters that identify the end of a variable. This suffix is expressed 1278 * in terms of a matcher allowing advanced suffix matches. 1279 * </p> 1280 * 1281 * @param suffixMatcher the suffix matcher to use, null ignored 1282 * @return this, to enable chaining 1283 * @throws IllegalArgumentException if the suffix matcher is null 1284 */ 1285 public StringSubstitutor setVariableSuffixMatcher(final StringMatcher suffixMatcher) { 1286 Validate.isTrue(suffixMatcher != null, "Variable suffix matcher must not be null!"); 1287 this.suffixMatcher = suffixMatcher; 1288 return this; 1289 } 1290 1291 /** 1292 * Internal method that substitutes the variables. 1293 * <p> 1294 * Most users of this class do not need to call this method. This method will be called automatically by another 1295 * (public) method. 1296 * </p> 1297 * <p> 1298 * Writers of subclasses can override this method if they need access to the substitution process at the start or 1299 * end. 1300 * </p> 1301 * 1302 * @param builder the string builder to substitute into, not null 1303 * @param offset the start offset within the builder, must be valid 1304 * @param length the length within the builder to be processed, must be valid 1305 * @return true if altered 1306 */ 1307 protected boolean substitute(final TextStringBuilder builder, final int offset, final int length) { 1308 return substitute(builder, offset, length, null).altered; 1309 } 1310 1311 /** 1312 * Recursive handler for multiple levels of interpolation. This is the main interpolation method, which resolves the 1313 * values of all variable references contained in the passed in text. 1314 * 1315 * @param builder the string builder to substitute into, not null 1316 * @param offset the start offset within the builder, must be valid 1317 * @param length the length within the builder to be processed, must be valid 1318 * @param priorVariables the stack keeping track of the replaced variables, may be null 1319 * @return The result. 1320 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 1321 * @since 1.9 1322 */ 1323 private Result substitute(final TextStringBuilder builder, final int offset, final int length, 1324 List<String> priorVariables) { 1325 Objects.requireNonNull(builder, "builder"); 1326 final StringMatcher prefixMatcher = getVariablePrefixMatcher(); 1327 final StringMatcher suffixMatcher = getVariableSuffixMatcher(); 1328 final char escapeCh = getEscapeChar(); 1329 final StringMatcher valueDelimMatcher = getValueDelimiterMatcher(); 1330 final boolean substitutionInVariablesEnabled = isEnableSubstitutionInVariables(); 1331 final boolean substitutionInValuesDisabled = isDisableSubstitutionInValues(); 1332 final boolean undefinedVariableException = isEnableUndefinedVariableException(); 1333 final boolean preserveEscapes = isPreserveEscapes(); 1334 1335 boolean altered = false; 1336 int lengthChange = 0; 1337 int bufEnd = offset + length; 1338 int pos = offset; 1339 int escPos = -1; 1340 outer: while (pos < bufEnd) { 1341 final int startMatchLen = prefixMatcher.isMatch(builder, pos, offset, bufEnd); 1342 if (startMatchLen == 0) { 1343 pos++; 1344 } else { 1345 // found variable start marker 1346 if (pos > offset && builder.charAt(pos - 1) == escapeCh) { 1347 // escape detected 1348 if (preserveEscapes) { 1349 // keep escape 1350 pos++; 1351 continue; 1352 } 1353 // mark esc ch for deletion if we find a complete variable 1354 escPos = pos - 1; 1355 } 1356 // find suffix 1357 int startPos = pos; 1358 pos += startMatchLen; 1359 int endMatchLen = 0; 1360 int nestedVarCount = 0; 1361 while (pos < bufEnd) { 1362 if (substitutionInVariablesEnabled && prefixMatcher.isMatch(builder, pos, offset, bufEnd) != 0) { 1363 // found a nested variable start 1364 endMatchLen = prefixMatcher.isMatch(builder, pos, offset, bufEnd); 1365 nestedVarCount++; 1366 pos += endMatchLen; 1367 continue; 1368 } 1369 1370 endMatchLen = suffixMatcher.isMatch(builder, pos, offset, bufEnd); 1371 if (endMatchLen == 0) { 1372 pos++; 1373 } else { 1374 // found variable end marker 1375 if (nestedVarCount == 0) { 1376 if (escPos >= 0) { 1377 // delete escape 1378 builder.deleteCharAt(escPos); 1379 escPos = -1; 1380 lengthChange--; 1381 altered = true; 1382 bufEnd--; 1383 pos = startPos + 1; 1384 startPos--; 1385 continue outer; 1386 } 1387 // get var name 1388 String varNameExpr = builder.midString(startPos + startMatchLen, 1389 pos - startPos - startMatchLen); 1390 if (substitutionInVariablesEnabled) { 1391 final TextStringBuilder bufName = new TextStringBuilder(varNameExpr); 1392 substitute(bufName, 0, bufName.length()); 1393 varNameExpr = bufName.toString(); 1394 } 1395 pos += endMatchLen; 1396 final int endPos = pos; 1397 1398 String varName = varNameExpr; 1399 String varDefaultValue = null; 1400 1401 if (valueDelimMatcher != null) { 1402 final char[] varNameExprChars = varNameExpr.toCharArray(); 1403 int valueDelimiterMatchLen = 0; 1404 for (int i = 0; i < varNameExprChars.length; i++) { 1405 // if there's any nested variable when nested variable substitution disabled, 1406 // then stop resolving name and default value. 1407 if (!substitutionInVariablesEnabled && prefixMatcher.isMatch(varNameExprChars, i, i, 1408 varNameExprChars.length) != 0) { 1409 break; 1410 } 1411 if (valueDelimMatcher.isMatch(varNameExprChars, i, 0, 1412 varNameExprChars.length) != 0) { 1413 valueDelimiterMatchLen = valueDelimMatcher.isMatch(varNameExprChars, i, 0, 1414 varNameExprChars.length); 1415 varName = varNameExpr.substring(0, i); 1416 varDefaultValue = varNameExpr.substring(i + valueDelimiterMatchLen); 1417 break; 1418 } 1419 } 1420 } 1421 1422 // on the first call initialize priorVariables 1423 if (priorVariables == null) { 1424 priorVariables = new ArrayList<>(); 1425 priorVariables.add(builder.midString(offset, length)); 1426 } 1427 1428 // handle cyclic substitution 1429 checkCyclicSubstitution(varName, priorVariables); 1430 priorVariables.add(varName); 1431 1432 // resolve the variable 1433 String varValue = resolveVariable(varName, builder, startPos, endPos); 1434 if (varValue == null) { 1435 varValue = varDefaultValue; 1436 } 1437 if (varValue != null) { 1438 final int varLen = varValue.length(); 1439 builder.replace(startPos, endPos, varValue); 1440 altered = true; 1441 int change = 0; 1442 if (!substitutionInValuesDisabled) { // recursive replace 1443 change = substitute(builder, startPos, varLen, priorVariables).lengthChange; 1444 } 1445 change = change + varLen - (endPos - startPos); 1446 pos += change; 1447 bufEnd += change; 1448 lengthChange += change; 1449 } else if (undefinedVariableException) { 1450 throw new IllegalArgumentException( 1451 String.format("Cannot resolve variable '%s' (enableSubstitutionInVariables=%s).", 1452 varName, substitutionInVariablesEnabled)); 1453 } 1454 1455 // remove variable from the cyclic stack 1456 priorVariables.remove(priorVariables.size() - 1); 1457 break; 1458 } 1459 nestedVarCount--; 1460 pos += endMatchLen; 1461 } 1462 } 1463 } 1464 } 1465 return new Result(altered, lengthChange); 1466 } 1467}