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.List; 021import java.util.Map; 022import java.util.Objects; 023import java.util.Properties; 024import java.util.function.Function; 025import java.util.stream.Collectors; 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 lets you use string lookups like: 140 * </p> 141 * 142 * <pre> 143 * final StringSubstitutor interpolator = StringSubstitutor.createInterpolator(); 144 * final String text = interpolator.replace( 145 * "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" 149 * + "Environment Variable: ${env:USERNAME}\n" 150 * + "File Content: ${file:UTF-8:src/test/resources/document.properties}\n" 151 * + "Java: ${java:version}\n" 152 * + "Localhost: ${localhost:canonical-name}\n" 153 * + "Properties File: ${properties:src/test/resources/document.properties::mykey}\n" 154 * + "Resource Bundle: ${resourceBundle:org.apache.commons.text.example.testResourceBundleLookup:mykey}\n" 155 * + "System Property: ${sys:user.dir}\n" 156 * + "URL Decoder: ${urlDecoder:Hello%20World%21}\n" 157 * + "URL Encoder: ${urlEncoder:Hello World!}\n" 158 * + "XML XPath: ${xml:src/test/resources/document.xml:/root/path/to/node}\n"); 159 * </pre> 160 * <p> 161 * For documentation and a full list of available lookups, see {@link StringLookupFactory}. 162 * </p> 163 * <p><strong>NOTE:</strong> The list of lookups available by default in {@link #createInterpolator()} changed 164 * in version {@code 1.10.0}. See the {@link StringLookupFactory} documentation for details and an explanation 165 * on how to reproduce the previous functionality. 166 * </p> 167 * 168 * <h2>Using Recursive Variable Replacement</h2> 169 * <p> 170 * Variable replacement can work recursively by calling {@link #setEnableSubstitutionInVariables(boolean)} with 171 * {@code true}. If a variable value contains a variable then that variable will also be replaced. Cyclic replacements 172 * are detected and will throw an exception. 173 * </p> 174 * <p> 175 * You can get the replace result to contain a variable prefix. For example: 176 * </p> 177 * 178 * <pre> 179 * "The variable ${${name}} must be used." 180 * </pre> 181 * 182 * <p> 183 * If the value of the "name" variable is "x", then only the variable "name" is replaced resulting in: 184 * </p> 185 * 186 * <pre> 187 * "The variable ${x} must be used." 188 * </pre> 189 * 190 * <p> 191 * To achieve this effect there are two possibilities: Either set a different prefix and suffix for variables which do 192 * not conflict with the result text you want to produce. The other possibility is to use the escape character, by 193 * default '$'. If this character is placed before a variable reference, this reference is ignored and won't be 194 * replaced. For example: 195 * </p> 196 * 197 * <pre> 198 * "The variable $${${name}} must be used." 199 * </pre> 200 * <p> 201 * In some complex scenarios you might even want to perform substitution in the names of variables, for instance 202 * </p> 203 * 204 * <pre> 205 * ${jre-${java.specification.version}} 206 * </pre> 207 * 208 * <p> 209 * {@code StringSubstitutor} supports this recursive substitution in variable names, but it has to be enabled explicitly 210 * by calling {@link #setEnableSubstitutionInVariables(boolean)} with {@code true}. 211 * </p> 212 * 213 * <h2>Thread Safety</h2> 214 * <p> 215 * This class is <b>not</b> thread safe. 216 * </p> 217 * 218 * @since 1.3 219 */ 220public class StringSubstitutor { 221 222 /** 223 * The low-level result of a substitution. 224 * 225 * @since 1.9 226 */ 227 private static final class Result { 228 229 /** Whether the buffer is altered. */ 230 public final boolean altered; 231 232 /** The length of change. */ 233 public final int lengthChange; 234 235 private Result(final boolean altered, final int lengthChange) { 236 this.altered = altered; 237 this.lengthChange = lengthChange; 238 } 239 240 @Override 241 public String toString() { 242 return "Result [altered=" + altered + ", lengthChange=" + lengthChange + "]"; 243 } 244 } 245 246 /** 247 * Constant for the default escape character. 248 */ 249 public static final char DEFAULT_ESCAPE = '$'; 250 251 /** 252 * The default variable default separator. 253 * 254 * @since 1.5. 255 */ 256 public static final String DEFAULT_VAR_DEFAULT = ":-"; 257 258 /** 259 * The default variable end separator. 260 * 261 * @since 1.5. 262 */ 263 public static final String DEFAULT_VAR_END = "}"; 264 265 /** 266 * The default variable start separator. 267 * 268 * @since 1.5. 269 */ 270 public static final String DEFAULT_VAR_START = "${"; 271 272 /** 273 * Constant for the default variable prefix. 274 */ 275 public static final StringMatcher DEFAULT_PREFIX = StringMatcherFactory.INSTANCE.stringMatcher(DEFAULT_VAR_START); 276 277 /** 278 * Constant for the default variable suffix. 279 */ 280 public static final StringMatcher DEFAULT_SUFFIX = StringMatcherFactory.INSTANCE.stringMatcher(DEFAULT_VAR_END); 281 282 /** 283 * Constant for the default value delimiter of a variable. 284 */ 285 public static final StringMatcher DEFAULT_VALUE_DELIMITER = StringMatcherFactory.INSTANCE 286 .stringMatcher(DEFAULT_VAR_DEFAULT); 287 288 /** 289 * Creates a new instance using the interpolator string lookup 290 * {@link StringLookupFactory#interpolatorStringLookup()}. 291 * <p> 292 * This StringSubstitutor lets you perform substitutions like: 293 * </p> 294 * 295 * <pre> 296 * StringSubstitutor.createInterpolator().replace( 297 * "OS name: ${sys:os.name}, user: ${env:USER}"); 298 * </pre> 299 * 300 * <p>The table below lists the lookups available by default in the returned instance. These 301 * may be modified through the use of the 302 * {@value org.apache.commons.text.lookup.StringLookupFactory#DEFAULT_STRING_LOOKUPS_PROPERTY} 303 * system property, as described in the {@link StringLookupFactory} documentation.</p> 304 * 305 * <p><strong>NOTE:</strong> The list of lookups available by default changed in version {@code 1.10.0}. 306 * Configuration via system property (as mentioned above) may be necessary to reproduce previous functionality. 307 * </p> 308 * 309 * <table> 310 * <caption>Default Lookups</caption> 311 * <tr> 312 * <th>Key</th> 313 * <th>Lookup</th> 314 * </tr> 315 * <tr> 316 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_BASE64_DECODER}</td> 317 * <td>{@link StringLookupFactory#base64DecoderStringLookup()}</td> 318 * </tr> 319 * <tr> 320 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_BASE64_ENCODER}</td> 321 * <td>{@link StringLookupFactory#base64EncoderStringLookup()}</td> 322 * </tr> 323 * <tr> 324 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_CONST}</td> 325 * <td>{@link StringLookupFactory#constantStringLookup()}</td> 326 * </tr> 327 * <tr> 328 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_DATE}</td> 329 * <td>{@link StringLookupFactory#dateStringLookup()}</td> 330 * </tr> 331 * <tr> 332 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_ENV}</td> 333 * <td>{@link StringLookupFactory#environmentVariableStringLookup()}</td> 334 * </tr> 335 * <tr> 336 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_FILE}</td> 337 * <td>{@link StringLookupFactory#fileStringLookup()}</td> 338 * </tr> 339 * <tr> 340 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_JAVA}</td> 341 * <td>{@link StringLookupFactory#javaPlatformStringLookup()}</td> 342 * </tr> 343 * <tr> 344 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_LOCALHOST}</td> 345 * <td>{@link StringLookupFactory#localHostStringLookup()}</td> 346 * </tr> 347 * <tr> 348 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_PROPERTIES}</td> 349 * <td>{@link StringLookupFactory#propertiesStringLookup()}</td> 350 * </tr> 351 * <tr> 352 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_RESOURCE_BUNDLE}</td> 353 * <td>{@link StringLookupFactory#resourceBundleStringLookup()}</td> 354 * </tr> 355 * <tr> 356 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_SYS}</td> 357 * <td>{@link StringLookupFactory#systemPropertyStringLookup()}</td> 358 * </tr> 359 * <tr> 360 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_URL_DECODER}</td> 361 * <td>{@link StringLookupFactory#urlDecoderStringLookup()}</td> 362 * </tr> 363 * <tr> 364 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_URL_ENCODER}</td> 365 * <td>{@link StringLookupFactory#urlEncoderStringLookup()}</td> 366 * </tr> 367 * <tr> 368 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_XML}</td> 369 * <td>{@link StringLookupFactory#xmlStringLookup()}</td> 370 * </tr> 371 * <tr> 372 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_XML_DECODER}</td> 373 * <td>{@link StringLookupFactory#xmlDecoderStringLookup()}</td> 374 * </tr> 375 * <tr> 376 * <td>{@value org.apache.commons.text.lookup.StringLookupFactory#KEY_XML_ENCODER}</td> 377 * <td>{@link StringLookupFactory#xmlEncoderStringLookup()}</td> 378 * </tr> 379 * </table> 380 * 381 * @return a new instance using the interpolator string lookup. 382 * @see StringLookupFactory#interpolatorStringLookup() 383 * @since 1.8 384 */ 385 public static StringSubstitutor createInterpolator() { 386 return new StringSubstitutor(StringLookupFactory.INSTANCE.interpolatorStringLookup()); 387 } 388 389 /** 390 * Replaces all the occurrences of variables in the given source object with their matching values from the map. 391 * 392 * @param <V> the type of the values in the map 393 * @param source the source text containing the variables to substitute, null returns null 394 * @param valueMap the map with the values, may be null 395 * @return The result of the replace operation 396 * @throws IllegalArgumentException if a variable is not found and enableUndefinedVariableException is true 397 */ 398 public static <V> String replace(final Object source, final Map<String, V> valueMap) { 399 return new StringSubstitutor(valueMap).replace(source); 400 } 401 402 /** 403 * Replaces all the occurrences of variables in the given source object with their matching values from the map. 404 * This method allows to specify a custom variable prefix and suffix 405 * 406 * @param <V> the type of the values in the map 407 * @param source the source text containing the variables to substitute, null returns null 408 * @param valueMap the map with the values, may be null 409 * @param prefix the prefix of variables, not null 410 * @param suffix the suffix of variables, not null 411 * @return The result of the replace operation 412 * @throws IllegalArgumentException if the prefix or suffix is null 413 * @throws IllegalArgumentException if a variable is not found and enableUndefinedVariableException is true 414 */ 415 public static <V> String replace(final Object source, final Map<String, V> valueMap, final String prefix, 416 final String suffix) { 417 return new StringSubstitutor(valueMap, prefix, suffix).replace(source); 418 } 419 420 /** 421 * Replaces all the occurrences of variables in the given source object with their matching values from the 422 * properties. 423 * 424 * @param source the source text containing the variables to substitute, null returns null 425 * @param valueProperties the properties with values, may be null 426 * @return The result of the replace operation 427 * @throws IllegalArgumentException if a variable is not found and enableUndefinedVariableException is true 428 */ 429 public static String replace(final Object source, final Properties valueProperties) { 430 if (valueProperties == null) { 431 return source.toString(); 432 } 433 return StringSubstitutor.replace(source, 434 valueProperties.stringPropertyNames().stream().collect(Collectors.toMap(Function.identity(), valueProperties::getProperty))); 435 } 436 437 /** 438 * Replaces all the occurrences of variables in the given source object with their matching values from the system 439 * properties. 440 * 441 * @param source the source text containing the variables to substitute, null returns null 442 * @return The result of the replace operation 443 * @throws IllegalArgumentException if a variable is not found and enableUndefinedVariableException is true 444 */ 445 public static String replaceSystemProperties(final Object source) { 446 return new StringSubstitutor(StringLookupFactory.INSTANCE.systemPropertyStringLookup()).replace(source); 447 } 448 449 /** 450 * The flag whether substitution in variable values is disabled. 451 */ 452 private boolean disableSubstitutionInValues; 453 454 /** 455 * The flag whether substitution in variable names is enabled. 456 */ 457 private boolean enableSubstitutionInVariables; 458 459 /** 460 * The flag whether exception should be thrown on undefined variable. 461 */ 462 private boolean enableUndefinedVariableException; 463 464 /** 465 * Stores the escape character. 466 */ 467 private char escapeChar; 468 469 /** 470 * Stores the variable prefix. 471 */ 472 private StringMatcher prefixMatcher; 473 474 /** 475 * Whether escapes should be preserved. Default is false; 476 */ 477 private boolean preserveEscapes; 478 479 /** 480 * Stores the variable suffix. 481 */ 482 private StringMatcher suffixMatcher; 483 484 /** 485 * Stores the default variable value delimiter. 486 */ 487 private StringMatcher valueDelimiterMatcher; 488 489 /** 490 * Variable resolution is delegated to an implementor of {@link StringLookup}. 491 */ 492 private StringLookup variableResolver; 493 494 /** 495 * Constructs a new instance with defaults for variable prefix and suffix and the escaping character. 496 */ 497 public StringSubstitutor() { 498 this((StringLookup) null, DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE); 499 } 500 501 /** 502 * Constructs a new initialized instance. Uses defaults for variable prefix and suffix and the escaping 503 * character. 504 * 505 * @param <V> the type of the values in the map 506 * @param valueMap the map with the variables' values, may be null 507 */ 508 public <V> StringSubstitutor(final Map<String, V> valueMap) { 509 this(StringLookupFactory.INSTANCE.mapStringLookup(valueMap), DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE); 510 } 511 512 /** 513 * Constructs a new initialized instance. Uses a default escaping character. 514 * 515 * @param <V> the type of the values in the map 516 * @param valueMap the map with the variables' values, may be null 517 * @param prefix the prefix for variables, not null 518 * @param suffix the suffix for variables, not null 519 * @throws IllegalArgumentException if the prefix or suffix is null 520 */ 521 public <V> StringSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix) { 522 this(StringLookupFactory.INSTANCE.mapStringLookup(valueMap), prefix, suffix, DEFAULT_ESCAPE); 523 } 524 525 /** 526 * Constructs a new initialized instance. 527 * 528 * @param <V> the type of the values in the map 529 * @param valueMap the map with the variables' values, may be null 530 * @param prefix the prefix for variables, not null 531 * @param suffix 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 <V> StringSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix, 536 final char escape) { 537 this(StringLookupFactory.INSTANCE.mapStringLookup(valueMap), prefix, suffix, escape); 538 } 539 540 /** 541 * Constructs a new initialized instance. 542 * 543 * @param <V> the type of the values in the map 544 * @param valueMap the map with the variables' values, may be null 545 * @param prefix the prefix for variables, not null 546 * @param suffix the suffix for variables, not null 547 * @param escape the escape character 548 * @param valueDelimiter the variable default value delimiter, may be null 549 * @throws IllegalArgumentException if the prefix or suffix is null 550 */ 551 public <V> StringSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix, 552 final char escape, final String valueDelimiter) { 553 this(StringLookupFactory.INSTANCE.mapStringLookup(valueMap), prefix, suffix, escape, valueDelimiter); 554 } 555 556 /** 557 * Constructs a new initialized instance. 558 * 559 * @param variableResolver the variable resolver, may be null 560 */ 561 public StringSubstitutor(final StringLookup variableResolver) { 562 this(variableResolver, DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE); 563 } 564 565 /** 566 * Constructs a new initialized instance. 567 * 568 * @param variableResolver the variable resolver, may be null 569 * @param prefix the prefix for variables, not null 570 * @param suffix the suffix for variables, not null 571 * @param escape the escape character 572 * @throws IllegalArgumentException if the prefix or suffix is null 573 */ 574 public StringSubstitutor(final StringLookup variableResolver, final String prefix, final String suffix, 575 final char escape) { 576 this.setVariableResolver(variableResolver); 577 this.setVariablePrefix(prefix); 578 this.setVariableSuffix(suffix); 579 this.setEscapeChar(escape); 580 this.setValueDelimiterMatcher(DEFAULT_VALUE_DELIMITER); 581 } 582 583 /** 584 * Constructs a new initialized instance. 585 * 586 * @param variableResolver the variable resolver, may be null 587 * @param prefix the prefix for variables, not null 588 * @param suffix the suffix for variables, not null 589 * @param escape the escape character 590 * @param valueDelimiter the variable default value delimiter string, may be null 591 * @throws IllegalArgumentException if the prefix or suffix is null 592 */ 593 public StringSubstitutor(final StringLookup variableResolver, final String prefix, final String suffix, 594 final char escape, final String valueDelimiter) { 595 this.setVariableResolver(variableResolver); 596 this.setVariablePrefix(prefix); 597 this.setVariableSuffix(suffix); 598 this.setEscapeChar(escape); 599 this.setValueDelimiter(valueDelimiter); 600 } 601 602 /** 603 * Constructs a new initialized instance. 604 * 605 * @param variableResolver the variable resolver, may be null 606 * @param prefixMatcher the prefix for variables, not null 607 * @param suffixMatcher the suffix for variables, not null 608 * @param escape the escape character 609 * @throws IllegalArgumentException if the prefix or suffix is null 610 */ 611 public StringSubstitutor(final StringLookup variableResolver, final StringMatcher prefixMatcher, 612 final StringMatcher suffixMatcher, final char escape) { 613 this(variableResolver, prefixMatcher, suffixMatcher, escape, DEFAULT_VALUE_DELIMITER); 614 } 615 616 /** 617 * Constructs a new initialized instance. 618 * 619 * @param variableResolver the variable resolver, may be null 620 * @param prefixMatcher the prefix for variables, not null 621 * @param suffixMatcher the suffix for variables, not null 622 * @param escape the escape character 623 * @param valueDelimiterMatcher the variable default value delimiter matcher, may be null 624 * @throws IllegalArgumentException if the prefix or suffix is null 625 */ 626 public StringSubstitutor(final StringLookup variableResolver, final StringMatcher prefixMatcher, 627 final StringMatcher suffixMatcher, final char escape, final StringMatcher valueDelimiterMatcher) { 628 this.setVariableResolver(variableResolver); 629 this.setVariablePrefixMatcher(prefixMatcher); 630 this.setVariableSuffixMatcher(suffixMatcher); 631 this.setEscapeChar(escape); 632 this.setValueDelimiterMatcher(valueDelimiterMatcher); 633 } 634 635 /** 636 * Creates a new instance based on the given StringSubstitutor. 637 * 638 * @param other The StringSubstitutor used as the source. 639 * @since 1.9 640 */ 641 public StringSubstitutor(final StringSubstitutor other) { 642 disableSubstitutionInValues = other.isDisableSubstitutionInValues(); 643 enableSubstitutionInVariables = other.isEnableSubstitutionInVariables(); 644 enableUndefinedVariableException = other.isEnableUndefinedVariableException(); 645 escapeChar = other.getEscapeChar(); 646 prefixMatcher = other.getVariablePrefixMatcher(); 647 preserveEscapes = other.isPreserveEscapes(); 648 suffixMatcher = other.getVariableSuffixMatcher(); 649 valueDelimiterMatcher = other.getValueDelimiterMatcher(); 650 variableResolver = other.getStringLookup(); 651 } 652 653 /** 654 * Checks if the specified variable is already in the stack (list) of variables. 655 * 656 * @param varName the variable name to check 657 * @param priorVariables the list of prior variables 658 */ 659 private void checkCyclicSubstitution(final String varName, final List<String> priorVariables) { 660 if (!priorVariables.contains(varName)) { 661 return; 662 } 663 final TextStringBuilder buf = new TextStringBuilder(256); 664 buf.append("Infinite loop in property interpolation of "); 665 buf.append(priorVariables.remove(0)); 666 buf.append(": "); 667 buf.appendWithSeparators(priorVariables, "->"); 668 throw new IllegalStateException(buf.toString()); 669 } 670 671 // Escape 672 /** 673 * Returns the escape character. 674 * 675 * @return The character used for escaping variable references 676 */ 677 public char getEscapeChar() { 678 return this.escapeChar; 679 } 680 681 /** 682 * Gets the StringLookup that is used to lookup variables. 683 * 684 * @return The StringLookup 685 */ 686 public StringLookup getStringLookup() { 687 return this.variableResolver; 688 } 689 690 /** 691 * Gets the variable default value delimiter matcher currently in use. 692 * <p> 693 * The variable default value delimiter is the character or characters that delimit the variable name and the 694 * variable default value. This delimiter is expressed in terms of a matcher allowing advanced variable default 695 * value delimiter matches. 696 * </p> 697 * <p> 698 * If it returns null, then the variable default value resolution is disabled. 699 * 700 * @return The variable default value delimiter matcher in use, may be null 701 */ 702 public StringMatcher getValueDelimiterMatcher() { 703 return valueDelimiterMatcher; 704 } 705 706 /** 707 * Gets the variable prefix matcher currently in use. 708 * <p> 709 * The variable prefix is the character or characters that identify the start of a variable. This prefix is 710 * expressed in terms of a matcher allowing advanced prefix matches. 711 * </p> 712 * 713 * @return The prefix matcher in use 714 */ 715 public StringMatcher getVariablePrefixMatcher() { 716 return prefixMatcher; 717 } 718 719 /** 720 * Gets the variable suffix matcher currently in use. 721 * <p> 722 * The variable suffix is the character or characters that identify the end of a variable. This suffix is expressed 723 * in terms of a matcher allowing advanced suffix matches. 724 * </p> 725 * 726 * @return The suffix matcher in use 727 */ 728 public StringMatcher getVariableSuffixMatcher() { 729 return suffixMatcher; 730 } 731 732 /** 733 * Returns a flag whether substitution is disabled in variable values.If set to <b>true</b>, the values of variables 734 * can contain other variables will not be processed and substituted original variable is evaluated, e.g. 735 * 736 * <pre> 737 * Map<String, String> valuesMap = new HashMap<>(); 738 * valuesMap.put("name", "Douglas ${surname}"); 739 * valuesMap.put("surname", "Crockford"); 740 * String templateString = "Hi ${name}"; 741 * StrSubstitutor sub = new StrSubstitutor(valuesMap); 742 * String resolvedString = sub.replace(templateString); 743 * </pre> 744 * 745 * yielding: 746 * 747 * <pre> 748 * Hi Douglas ${surname} 749 * </pre> 750 * 751 * @return The substitution in variable values flag 752 */ 753 public boolean isDisableSubstitutionInValues() { 754 return disableSubstitutionInValues; 755 } 756 757 /** 758 * Returns a flag whether substitution is done in variable names. 759 * 760 * @return The substitution in variable names flag 761 */ 762 public boolean isEnableSubstitutionInVariables() { 763 return enableSubstitutionInVariables; 764 } 765 766 /** 767 * Returns a flag whether exception can be thrown upon undefined variable. 768 * 769 * @return The fail on undefined variable flag 770 */ 771 public boolean isEnableUndefinedVariableException() { 772 return enableUndefinedVariableException; 773 } 774 775 /** 776 * Returns the flag controlling whether escapes are preserved during substitution. 777 * 778 * @return The preserve escape flag 779 */ 780 public boolean isPreserveEscapes() { 781 return preserveEscapes; 782 } 783 784 /** 785 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 786 * array as a template. The array is not altered by this method. 787 * 788 * @param source the character array to replace in, not altered, null returns null 789 * @return The result of the replace operation 790 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 791 */ 792 public String replace(final char[] source) { 793 if (source == null) { 794 return null; 795 } 796 final TextStringBuilder buf = new TextStringBuilder(source.length).append(source); 797 substitute(buf, 0, source.length); 798 return buf.toString(); 799 } 800 801 /** 802 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 803 * array as a template. The array is not altered by this method. 804 * <p> 805 * Only the specified portion of the array will be processed. The rest of the array is not processed, and is not 806 * returned. 807 * </p> 808 * 809 * @param source the character array to replace in, not altered, null returns null 810 * @param offset the start offset within the array, must be valid 811 * @param length the length within the array to be processed, must be valid 812 * @return The result of the replace operation 813 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 814 * @throws StringIndexOutOfBoundsException if {@code offset} is not in the 815 * range {@code 0 <= offset <= chars.length} 816 * @throws StringIndexOutOfBoundsException if {@code length < 0} 817 * @throws StringIndexOutOfBoundsException if {@code offset + length > chars.length} 818 */ 819 public String replace(final char[] source, final int offset, final int length) { 820 if (source == null) { 821 return null; 822 } 823 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 824 substitute(buf, 0, length); 825 return buf.toString(); 826 } 827 828 /** 829 * Replaces all the occurrences of variables with their matching values from the resolver using the given source as 830 * a template. The source is not altered by this method. 831 * 832 * @param source the buffer to use as a template, not changed, null returns null 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 CharSequence source) { 837 if (source == null) { 838 return null; 839 } 840 return replace(source, 0, source.length()); 841 } 842 843 /** 844 * Replaces all the occurrences of variables with their matching values from the resolver using the given source as 845 * a template. The source is not altered by this method. 846 * <p> 847 * Only the specified portion of the buffer will be processed. The rest of the buffer is not processed, and is not 848 * returned. 849 * </p> 850 * 851 * @param source the buffer to use as a template, not changed, null returns null 852 * @param offset the start offset within the array, must be valid 853 * @param length the length within the array to be processed, must be valid 854 * @return The result of the replace operation 855 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 856 */ 857 public String replace(final CharSequence source, final int offset, final int length) { 858 if (source == null) { 859 return null; 860 } 861 final TextStringBuilder buf = new TextStringBuilder(length).append(source.toString(), offset, length); 862 substitute(buf, 0, length); 863 return buf.toString(); 864 } 865 866 /** 867 * Replaces all the occurrences of variables in the given source object with their matching values from the 868 * resolver. The input source object is converted to a string using {@code toString} and is not altered. 869 * 870 * @param source the source to replace in, null returns null 871 * @return The result of the replace operation 872 * @throws IllegalArgumentException if a variable is not found and enableUndefinedVariableException is true 873 */ 874 public String replace(final Object source) { 875 if (source == null) { 876 return null; 877 } 878 final TextStringBuilder buf = new TextStringBuilder().append(source); 879 substitute(buf, 0, buf.length()); 880 return buf.toString(); 881 } 882 883 /** 884 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 885 * string as a template. 886 * 887 * @param source the string to replace in, null returns null 888 * @return The result of the replace operation 889 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 890 */ 891 public String replace(final String source) { 892 if (source == null) { 893 return null; 894 } 895 final TextStringBuilder buf = new TextStringBuilder(source); 896 if (!substitute(buf, 0, source.length())) { 897 return source; 898 } 899 return buf.toString(); 900 } 901 902 /** 903 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 904 * string as a template. 905 * <p> 906 * Only the specified portion of the string will be processed. The rest of the string is not processed, and is not 907 * returned. 908 * </p> 909 * 910 * @param source the string to replace in, null returns null 911 * @param offset the start offset within the source, must be valid 912 * @param length the length within the source to be processed, must be valid 913 * @return The result of the replace operation 914 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 915 * @throws StringIndexOutOfBoundsException if {@code offset} is not in the 916 * range {@code 0 <= offset <= source.length()} 917 * @throws StringIndexOutOfBoundsException if {@code length < 0} 918 * @throws StringIndexOutOfBoundsException if {@code offset + length > source.length()} 919 */ 920 public String replace(final String source, final int offset, final int length) { 921 if (source == null) { 922 return null; 923 } 924 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 925 if (!substitute(buf, 0, length)) { 926 return source.substring(offset, offset + length); 927 } 928 return buf.toString(); 929 } 930 931 /** 932 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 933 * buffer as a template. The buffer is not altered by this method. 934 * 935 * @param source the buffer to use as a template, not changed, null returns null 936 * @return The result of the replace operation 937 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 938 */ 939 public String replace(final StringBuffer source) { 940 if (source == null) { 941 return null; 942 } 943 final TextStringBuilder buf = new TextStringBuilder(source.length()).append(source); 944 substitute(buf, 0, buf.length()); 945 return buf.toString(); 946 } 947 948 /** 949 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 950 * buffer as a template. The buffer is not altered by this method. 951 * <p> 952 * Only the specified portion of the buffer will be processed. The rest of the buffer is not processed, and is not 953 * returned. 954 * </p> 955 * 956 * @param source the buffer to use as a template, not changed, null returns null 957 * @param offset the start offset within the source, must be valid 958 * @param length the length within the source to be processed, must be valid 959 * @return The result of the replace operation 960 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 961 */ 962 public String replace(final StringBuffer source, final int offset, final int length) { 963 if (source == null) { 964 return null; 965 } 966 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 967 substitute(buf, 0, length); 968 return buf.toString(); 969 } 970 971 /** 972 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 973 * builder as a template. The builder is not altered by this method. 974 * 975 * @param source the builder to use as a template, not changed, null returns null 976 * @return The result of the replace operation 977 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 978 */ 979 public String replace(final TextStringBuilder source) { 980 if (source == null) { 981 return null; 982 } 983 final TextStringBuilder builder = new TextStringBuilder(source.length()).append(source); 984 substitute(builder, 0, builder.length()); 985 return builder.toString(); 986 } 987 988 /** 989 * Replaces all the occurrences of variables with their matching values from the resolver using the given source 990 * builder as a template. The builder is not altered by this method. 991 * <p> 992 * Only the specified portion of the builder will be processed. The rest of the builder is not processed, and is not 993 * returned. 994 * </p> 995 * 996 * @param source the builder to use as a template, not changed, null returns null 997 * @param offset the start offset within the source, must be valid 998 * @param length the length within the source to be processed, must be valid 999 * @return The result of the replace operation 1000 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 1001 */ 1002 public String replace(final TextStringBuilder source, final int offset, final int length) { 1003 if (source == null) { 1004 return null; 1005 } 1006 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 1007 substitute(buf, 0, length); 1008 return buf.toString(); 1009 } 1010 1011 /** 1012 * Replaces all the occurrences of variables within the given source buffer with their matching values from the 1013 * resolver. The buffer is updated with the result. 1014 * 1015 * @param source the buffer to replace in, updated, null returns zero 1016 * @return true if altered 1017 */ 1018 public boolean replaceIn(final StringBuffer source) { 1019 if (source == null) { 1020 return false; 1021 } 1022 return replaceIn(source, 0, source.length()); 1023 } 1024 1025 /** 1026 * Replaces all the occurrences of variables within the given source buffer with their matching values from the 1027 * resolver. The buffer is updated with the result. 1028 * <p> 1029 * Only the specified portion of the buffer will be processed. The rest of the buffer is not processed, but it is 1030 * not deleted. 1031 * </p> 1032 * 1033 * @param source the buffer to replace in, updated, null returns zero 1034 * @param offset the start offset within the source, must be valid 1035 * @param length the length within the source to be processed, must be valid 1036 * @return true if altered 1037 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 1038 */ 1039 public boolean replaceIn(final StringBuffer source, final int offset, final int length) { 1040 if (source == null) { 1041 return false; 1042 } 1043 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 1044 if (!substitute(buf, 0, length)) { 1045 return false; 1046 } 1047 source.replace(offset, offset + length, buf.toString()); 1048 return true; 1049 } 1050 1051 /** 1052 * Replaces all the occurrences of variables within the given source buffer with their matching values from the 1053 * resolver. The buffer is updated with the result. 1054 * 1055 * @param source the buffer to replace in, updated, null returns zero 1056 * @return true if altered 1057 */ 1058 public boolean replaceIn(final StringBuilder source) { 1059 if (source == null) { 1060 return false; 1061 } 1062 return replaceIn(source, 0, source.length()); 1063 } 1064 1065 /** 1066 * Replaces all the occurrences of variables within the given source builder with their matching values from the 1067 * resolver. The builder is updated with the result. 1068 * <p> 1069 * Only the specified portion of the buffer will be processed. The rest of the buffer is not processed, but it is 1070 * not deleted. 1071 * </p> 1072 * 1073 * @param source the buffer to replace in, updated, null returns zero 1074 * @param offset the start offset within the source, must be valid 1075 * @param length the length within the source to be processed, must be valid 1076 * @return true if altered 1077 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 1078 */ 1079 public boolean replaceIn(final StringBuilder source, final int offset, final int length) { 1080 if (source == null) { 1081 return false; 1082 } 1083 final TextStringBuilder buf = new TextStringBuilder(length).append(source, offset, length); 1084 if (!substitute(buf, 0, length)) { 1085 return false; 1086 } 1087 source.replace(offset, offset + length, buf.toString()); 1088 return true; 1089 } 1090 1091 /** 1092 * Replaces all the occurrences of variables within the given source builder with their matching values from the 1093 * resolver. 1094 * 1095 * @param source the builder to replace in, updated, null returns zero 1096 * @return true if altered 1097 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 1098 */ 1099 public boolean replaceIn(final TextStringBuilder source) { 1100 if (source == null) { 1101 return false; 1102 } 1103 return substitute(source, 0, source.length()); 1104 } 1105 1106 /** 1107 * Replaces all the occurrences of variables within the given source builder with their matching values from the 1108 * resolver. 1109 * <p> 1110 * Only the specified portion of the builder will be processed. The rest of the builder is not processed, but it is 1111 * not deleted. 1112 * </p> 1113 * 1114 * @param source the builder to replace in, null returns zero 1115 * @param offset the start offset within the source, must be valid 1116 * @param length the length within the source to be processed, must be valid 1117 * @return true if altered 1118 * @throws IllegalArgumentException if variable is not found when its allowed to throw exception 1119 */ 1120 public boolean replaceIn(final TextStringBuilder source, final int offset, final int length) { 1121 if (source == null) { 1122 return false; 1123 } 1124 return substitute(source, offset, length); 1125 } 1126 1127 /** 1128 * Internal method that resolves the value of a variable. 1129 * <p> 1130 * Most users of this class do not need to call this method. This method is called automatically by the substitution 1131 * process. 1132 * </p> 1133 * <p> 1134 * Writers of subclasses can override this method if they need to alter how each substitution occurs. The method is 1135 * passed the variable's name and must return the corresponding value. This implementation uses the 1136 * {@link #getStringLookup()} with the variable's name as the key. 1137 * </p> 1138 * 1139 * @param variableName the name of the variable, not null 1140 * @param buf the buffer where the substitution is occurring, not null 1141 * @param startPos the start position of the variable including the prefix, valid 1142 * @param endPos the end position of the variable including the suffix, valid 1143 * @return The variable's value or <b>null</b> if the variable is unknown 1144 */ 1145 protected String resolveVariable(final String variableName, final TextStringBuilder buf, final int startPos, 1146 final int endPos) { 1147 final StringLookup resolver = getStringLookup(); 1148 if (resolver == null) { 1149 return null; 1150 } 1151 return resolver.lookup(variableName); 1152 } 1153 1154 /** 1155 * Sets a flag whether substitution is done in variable values (recursive). 1156 * 1157 * @param disableSubstitutionInValues true if substitution in variable value are disabled 1158 * @return this, to enable chaining 1159 */ 1160 public StringSubstitutor setDisableSubstitutionInValues(final boolean disableSubstitutionInValues) { 1161 this.disableSubstitutionInValues = disableSubstitutionInValues; 1162 return this; 1163 } 1164 1165 /** 1166 * Sets a flag whether substitution is done in variable names. If set to <b>true</b>, the names of variables can 1167 * contain other variables which are processed first before the original variable is evaluated, e.g. 1168 * {@code ${jre-${java.version}}}. The default value is <b>false</b>. 1169 * 1170 * @param enableSubstitutionInVariables the new value of the flag 1171 * @return this, to enable chaining 1172 */ 1173 public StringSubstitutor setEnableSubstitutionInVariables(final boolean enableSubstitutionInVariables) { 1174 this.enableSubstitutionInVariables = enableSubstitutionInVariables; 1175 return this; 1176 } 1177 1178 /** 1179 * Sets a flag whether exception should be thrown if any variable is undefined. 1180 * 1181 * @param failOnUndefinedVariable true if exception should be thrown on undefined variable 1182 * @return this, to enable chaining 1183 */ 1184 public StringSubstitutor setEnableUndefinedVariableException(final boolean failOnUndefinedVariable) { 1185 this.enableUndefinedVariableException = failOnUndefinedVariable; 1186 return this; 1187 } 1188 1189 /** 1190 * Sets the escape character. If this character is placed before a variable reference in the source text, this 1191 * variable will be ignored. 1192 * 1193 * @param escapeCharacter the escape character (0 for disabling escaping) 1194 * @return this, to enable chaining 1195 */ 1196 public StringSubstitutor setEscapeChar(final char escapeCharacter) { 1197 this.escapeChar = escapeCharacter; 1198 return this; 1199 } 1200 1201 /** 1202 * Sets a flag controlling whether escapes are preserved during substitution. If set to <b>true</b>, the escape 1203 * character is retained during substitution (e.g. {@code $${this-is-escaped}} remains {@code $${this-is-escaped}}). 1204 * If set to <b>false</b>, the escape character is removed during substitution (e.g. {@code $${this-is-escaped}} 1205 * becomes {@code ${this-is-escaped}}). The default value is <b>false</b> 1206 * 1207 * @param preserveEscapes true if escapes are to be preserved 1208 * @return this, to enable chaining 1209 */ 1210 public StringSubstitutor setPreserveEscapes(final boolean preserveEscapes) { 1211 this.preserveEscapes = preserveEscapes; 1212 return this; 1213 } 1214 1215 /** 1216 * Sets the variable default value delimiter to use. 1217 * <p> 1218 * The variable default value delimiter is the character or characters that delimit the variable name and the 1219 * variable default value. This method allows a single character variable default value delimiter to be easily set. 1220 * </p> 1221 * 1222 * @param valueDelimiter the variable default value delimiter character to use 1223 * @return this, to enable chaining 1224 */ 1225 public StringSubstitutor setValueDelimiter(final char valueDelimiter) { 1226 return setValueDelimiterMatcher(StringMatcherFactory.INSTANCE.charMatcher(valueDelimiter)); 1227 } 1228 1229 /** 1230 * Sets the variable default value delimiter to use. 1231 * <p> 1232 * The variable default value delimiter is the character or characters that delimit the variable name and the 1233 * variable default value. This method allows a string variable default value delimiter to be easily set. 1234 * </p> 1235 * <p> 1236 * If the {@code valueDelimiter} is null or empty string, then the variable default value resolution becomes 1237 * disabled. 1238 * </p> 1239 * 1240 * @param valueDelimiter the variable default value delimiter string to use, may be null or empty 1241 * @return this, to enable chaining 1242 */ 1243 public StringSubstitutor setValueDelimiter(final String valueDelimiter) { 1244 if (valueDelimiter == null || valueDelimiter.isEmpty()) { 1245 setValueDelimiterMatcher(null); 1246 return this; 1247 } 1248 return setValueDelimiterMatcher(StringMatcherFactory.INSTANCE.stringMatcher(valueDelimiter)); 1249 } 1250 1251 /** 1252 * Sets the variable default value delimiter matcher to use. 1253 * <p> 1254 * The variable default value delimiter is the character or characters that delimit the variable name and the 1255 * variable default value. This delimiter is expressed in terms of a matcher allowing advanced variable default 1256 * value delimiter matches. 1257 * </p> 1258 * <p> 1259 * If the {@code valueDelimiterMatcher} is null, then the variable default value resolution becomes disabled. 1260 * </p> 1261 * 1262 * @param valueDelimiterMatcher variable default value delimiter matcher to use, may be null 1263 * @return this, to enable chaining 1264 */ 1265 public StringSubstitutor setValueDelimiterMatcher(final StringMatcher valueDelimiterMatcher) { 1266 this.valueDelimiterMatcher = valueDelimiterMatcher; 1267 return this; 1268 } 1269 1270 /** 1271 * Sets the variable prefix to use. 1272 * <p> 1273 * The variable prefix is the character or characters that identify the start of a variable. This method allows a 1274 * single character prefix to be easily set. 1275 * </p> 1276 * 1277 * @param prefix the prefix character to use 1278 * @return this, to enable chaining 1279 */ 1280 public StringSubstitutor setVariablePrefix(final char prefix) { 1281 return setVariablePrefixMatcher(StringMatcherFactory.INSTANCE.charMatcher(prefix)); 1282 } 1283 1284 /** 1285 * Sets the variable prefix to use. 1286 * <p> 1287 * The variable prefix is the character or characters that identify the start of a variable. This method allows a 1288 * string prefix to be easily set. 1289 * </p> 1290 * 1291 * @param prefix the prefix for variables, not null 1292 * @return this, to enable chaining 1293 * @throws IllegalArgumentException if the prefix is null 1294 */ 1295 public StringSubstitutor setVariablePrefix(final String prefix) { 1296 Validate.isTrue(prefix != null, "Variable prefix must not be null!"); 1297 return setVariablePrefixMatcher(StringMatcherFactory.INSTANCE.stringMatcher(prefix)); 1298 } 1299 1300 /** 1301 * Sets the variable prefix matcher currently in use. 1302 * <p> 1303 * The variable prefix is the character or characters that identify the start of a variable. This prefix is 1304 * expressed in terms of a matcher allowing advanced prefix matches. 1305 * </p> 1306 * 1307 * @param prefixMatcher the prefix matcher to use, null ignored 1308 * @return this, to enable chaining 1309 * @throws IllegalArgumentException if the prefix matcher is null 1310 */ 1311 public StringSubstitutor setVariablePrefixMatcher(final StringMatcher prefixMatcher) { 1312 Validate.isTrue(prefixMatcher != null, "Variable prefix matcher must not be null!"); 1313 this.prefixMatcher = prefixMatcher; 1314 return this; 1315 } 1316 1317 /** 1318 * Sets the VariableResolver that is used to lookup variables. 1319 * 1320 * @param variableResolver the VariableResolver 1321 * @return this, to enable chaining 1322 */ 1323 public StringSubstitutor setVariableResolver(final StringLookup variableResolver) { 1324 this.variableResolver = variableResolver; 1325 return this; 1326 } 1327 1328 /** 1329 * Sets the variable suffix to use. 1330 * <p> 1331 * The variable suffix is the character or characters that identify the end of a variable. This method allows a 1332 * single character suffix to be easily set. 1333 * </p> 1334 * 1335 * @param suffix the suffix character to use 1336 * @return this, to enable chaining 1337 */ 1338 public StringSubstitutor setVariableSuffix(final char suffix) { 1339 return setVariableSuffixMatcher(StringMatcherFactory.INSTANCE.charMatcher(suffix)); 1340 } 1341 1342 /** 1343 * Sets the variable suffix to use. 1344 * <p> 1345 * The variable suffix is the character or characters that identify the end of a variable. This method allows a 1346 * string suffix to be easily set. 1347 * </p> 1348 * 1349 * @param suffix the suffix for variables, not null 1350 * @return this, to enable chaining 1351 * @throws IllegalArgumentException if the suffix is null 1352 */ 1353 public StringSubstitutor setVariableSuffix(final String suffix) { 1354 Validate.isTrue(suffix != null, "Variable suffix must not be null!"); 1355 return setVariableSuffixMatcher(StringMatcherFactory.INSTANCE.stringMatcher(suffix)); 1356 } 1357 1358 /** 1359 * Sets the variable suffix matcher currently in use. 1360 * <p> 1361 * The variable suffix is the character or characters that identify the end of a variable. This suffix is expressed 1362 * in terms of a matcher allowing advanced suffix matches. 1363 * </p> 1364 * 1365 * @param suffixMatcher the suffix matcher to use, null ignored 1366 * @return this, to enable chaining 1367 * @throws IllegalArgumentException if the suffix matcher is null 1368 */ 1369 public StringSubstitutor setVariableSuffixMatcher(final StringMatcher suffixMatcher) { 1370 Validate.isTrue(suffixMatcher != null, "Variable suffix matcher must not be null!"); 1371 this.suffixMatcher = suffixMatcher; 1372 return this; 1373 } 1374 1375 /** 1376 * Internal method that substitutes the variables. 1377 * <p> 1378 * Most users of this class do not need to call this method. This method will be called automatically by another 1379 * (public) method. 1380 * </p> 1381 * <p> 1382 * Writers of subclasses can override this method if they need access to the substitution process at the start or 1383 * end. 1384 * </p> 1385 * 1386 * @param builder the string builder to substitute into, not null 1387 * @param offset the start offset within the builder, must be valid 1388 * @param length the length within the builder to be processed, must be valid 1389 * @return true if altered 1390 */ 1391 protected boolean substitute(final TextStringBuilder builder, final int offset, final int length) { 1392 return substitute(builder, offset, length, null).altered; 1393 } 1394 1395 /** 1396 * Recursive handler for multiple levels of interpolation. This is the main interpolation method, which resolves the 1397 * values of all variable references contained in the passed in text. 1398 * 1399 * @param builder the string builder to substitute into, not null 1400 * @param offset the start offset within the builder, must be valid 1401 * @param length the length within the builder to be processed, must be valid 1402 * @param priorVariables the stack keeping track of the replaced variables, may be null 1403 * @return The result. 1404 * @throws IllegalArgumentException if variable is not found and <pre>isEnableUndefinedVariableException()==true</pre> 1405 * @since 1.9 1406 */ 1407 private Result substitute(final TextStringBuilder builder, final int offset, final int length, 1408 List<String> priorVariables) { 1409 Objects.requireNonNull(builder, "builder"); 1410 final StringMatcher prefixMatcher = getVariablePrefixMatcher(); 1411 final StringMatcher suffixMatcher = getVariableSuffixMatcher(); 1412 final char escapeCh = getEscapeChar(); 1413 final StringMatcher valueDelimMatcher = getValueDelimiterMatcher(); 1414 final boolean substitutionInVariablesEnabled = isEnableSubstitutionInVariables(); 1415 final boolean substitutionInValuesDisabled = isDisableSubstitutionInValues(); 1416 final boolean undefinedVariableException = isEnableUndefinedVariableException(); 1417 final boolean preserveEscapes = isPreserveEscapes(); 1418 1419 boolean altered = false; 1420 int lengthChange = 0; 1421 int bufEnd = offset + length; 1422 int pos = offset; 1423 int escPos = -1; 1424 outer: while (pos < bufEnd) { 1425 final int startMatchLen = prefixMatcher.isMatch(builder, pos, offset, bufEnd); 1426 if (startMatchLen == 0) { 1427 pos++; 1428 } else { 1429 // found variable start marker 1430 if (pos > offset && builder.charAt(pos - 1) == escapeCh) { 1431 // escape detected 1432 if (preserveEscapes) { 1433 // keep escape 1434 pos++; 1435 continue; 1436 } 1437 // mark esc ch for deletion if we find a complete variable 1438 escPos = pos - 1; 1439 } 1440 // find suffix 1441 int startPos = pos; 1442 pos += startMatchLen; 1443 int endMatchLen = 0; 1444 int nestedVarCount = 0; 1445 while (pos < bufEnd) { 1446 if (substitutionInVariablesEnabled && prefixMatcher.isMatch(builder, pos, offset, bufEnd) != 0) { 1447 // found a nested variable start 1448 endMatchLen = prefixMatcher.isMatch(builder, pos, offset, bufEnd); 1449 nestedVarCount++; 1450 pos += endMatchLen; 1451 continue; 1452 } 1453 1454 endMatchLen = suffixMatcher.isMatch(builder, pos, offset, bufEnd); 1455 if (endMatchLen == 0) { 1456 pos++; 1457 } else { 1458 // found variable end marker 1459 if (nestedVarCount == 0) { 1460 if (escPos >= 0) { 1461 // delete escape 1462 builder.deleteCharAt(escPos); 1463 escPos = -1; 1464 lengthChange--; 1465 altered = true; 1466 bufEnd--; 1467 pos = startPos + 1; 1468 startPos--; 1469 continue outer; 1470 } 1471 // get var name 1472 String varNameExpr = builder.midString(startPos + startMatchLen, 1473 pos - startPos - startMatchLen); 1474 if (substitutionInVariablesEnabled) { 1475 final TextStringBuilder bufName = new TextStringBuilder(varNameExpr); 1476 substitute(bufName, 0, bufName.length()); 1477 varNameExpr = bufName.toString(); 1478 } 1479 pos += endMatchLen; 1480 final int endPos = pos; 1481 1482 String varName = varNameExpr; 1483 String varDefaultValue = null; 1484 1485 if (valueDelimMatcher != null) { 1486 final char[] varNameExprChars = varNameExpr.toCharArray(); 1487 int valueDelimiterMatchLen = 0; 1488 for (int i = 0; i < varNameExprChars.length; i++) { 1489 // if there's any nested variable when nested variable substitution disabled, 1490 // then stop resolving name and default value. 1491 if (!substitutionInVariablesEnabled && prefixMatcher.isMatch(varNameExprChars, i, i, 1492 varNameExprChars.length) != 0) { 1493 break; 1494 } 1495 if (valueDelimMatcher.isMatch(varNameExprChars, i, 0, 1496 varNameExprChars.length) != 0) { 1497 valueDelimiterMatchLen = valueDelimMatcher.isMatch(varNameExprChars, i, 0, 1498 varNameExprChars.length); 1499 varName = varNameExpr.substring(0, i); 1500 varDefaultValue = varNameExpr.substring(i + valueDelimiterMatchLen); 1501 break; 1502 } 1503 } 1504 } 1505 1506 // on the first call initialize priorVariables 1507 if (priorVariables == null) { 1508 priorVariables = new ArrayList<>(); 1509 priorVariables.add(builder.midString(offset, length)); 1510 } 1511 1512 // handle cyclic substitution 1513 checkCyclicSubstitution(varName, priorVariables); 1514 priorVariables.add(varName); 1515 1516 // resolve the variable 1517 String varValue = resolveVariable(varName, builder, startPos, endPos); 1518 if (varValue == null) { 1519 varValue = varDefaultValue; 1520 } 1521 if (varValue != null) { 1522 final int varLen = varValue.length(); 1523 builder.replace(startPos, endPos, varValue); 1524 altered = true; 1525 int change = 0; 1526 if (!substitutionInValuesDisabled) { // recursive replace 1527 change = substitute(builder, startPos, varLen, priorVariables).lengthChange; 1528 } 1529 change = change + varLen - (endPos - startPos); 1530 pos += change; 1531 bufEnd += change; 1532 lengthChange += change; 1533 } else if (undefinedVariableException) { 1534 throw new IllegalArgumentException( 1535 String.format("Cannot resolve variable '%s' (enableSubstitutionInVariables=%s).", 1536 varName, substitutionInVariablesEnabled)); 1537 } 1538 1539 // remove variable from the cyclic stack 1540 priorVariables.remove(priorVariables.size() - 1); 1541 break; 1542 } 1543 nestedVarCount--; 1544 pos += endMatchLen; 1545 } 1546 } 1547 } 1548 } 1549 return new Result(altered, lengthChange); 1550 } 1551 1552 /** 1553 * Returns a string representation of the object. 1554 * 1555 * @return a string representation of the object. 1556 * @since 1.11.0 1557 */ 1558 @Override 1559 public String toString() { 1560 final StringBuilder builder = new StringBuilder(); 1561 builder.append("StringSubstitutor [disableSubstitutionInValues=").append(disableSubstitutionInValues).append(", enableSubstitutionInVariables=") 1562 .append(enableSubstitutionInVariables).append(", enableUndefinedVariableException=").append(enableUndefinedVariableException) 1563 .append(", escapeChar=").append(escapeChar).append(", prefixMatcher=").append(prefixMatcher).append(", preserveEscapes=") 1564 .append(preserveEscapes).append(", suffixMatcher=").append(suffixMatcher).append(", valueDelimiterMatcher=").append(valueDelimiterMatcher) 1565 .append(", variableResolver=").append(variableResolver).append("]"); 1566 return builder.toString(); 1567 } 1568}