001//////////////////////////////////////////////////////////////////////////////// 002// checkstyle: Checks Java source code for adherence to a set of rules. 003// Copyright (C) 2001-2017 the original author or authors. 004// 005// This library is free software; you can redistribute it and/or 006// modify it under the terms of the GNU Lesser General Public 007// License as published by the Free Software Foundation; either 008// version 2.1 of the License, or (at your option) any later version. 009// 010// This library is distributed in the hope that it will be useful, 011// but WITHOUT ANY WARRANTY; without even the implied warranty of 012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 013// Lesser General Public License for more details. 014// 015// You should have received a copy of the GNU Lesser General Public 016// License along with this library; if not, write to the Free Software 017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 018//////////////////////////////////////////////////////////////////////////////// 019 020package com.puppycrawl.tools.checkstyle.checks.whitespace; 021 022import com.puppycrawl.tools.checkstyle.api.AbstractCheck; 023import com.puppycrawl.tools.checkstyle.api.DetailAST; 024import com.puppycrawl.tools.checkstyle.api.TokenTypes; 025import com.puppycrawl.tools.checkstyle.utils.CommonUtils; 026 027/** 028 * Checks that a token is surrounded by whitespace. 029 * 030 * <p>By default the check will check the following operators: 031 * {@link TokenTypes#LITERAL_ASSERT ASSERT}, 032 * {@link TokenTypes#ASSIGN ASSIGN}, 033 * {@link TokenTypes#BAND BAND}, 034 * {@link TokenTypes#BAND_ASSIGN BAND_ASSIGN}, 035 * {@link TokenTypes#BOR BOR}, 036 * {@link TokenTypes#BOR_ASSIGN BOR_ASSIGN}, 037 * {@link TokenTypes#BSR BSR}, 038 * {@link TokenTypes#BSR_ASSIGN BSR_ASSIGN}, 039 * {@link TokenTypes#BXOR BXOR}, 040 * {@link TokenTypes#BXOR_ASSIGN BXOR_ASSIGN}, 041 * {@link TokenTypes#COLON COLON}, 042 * {@link TokenTypes#DIV DIV}, 043 * {@link TokenTypes#DIV_ASSIGN DIV_ASSIGN}, 044 * {@link TokenTypes#DO_WHILE DO_WHILE}, 045 * {@link TokenTypes#EQUAL EQUAL}, 046 * {@link TokenTypes#GE GE}, 047 * {@link TokenTypes#GT GT}, 048 * {@link TokenTypes#LAND LAND}, 049 * {@link TokenTypes#LCURLY LCURLY}, 050 * {@link TokenTypes#LE LE}, 051 * {@link TokenTypes#LITERAL_CATCH LITERAL_CATCH}, 052 * {@link TokenTypes#LITERAL_DO LITERAL_DO}, 053 * {@link TokenTypes#LITERAL_ELSE LITERAL_ELSE}, 054 * {@link TokenTypes#LITERAL_FINALLY LITERAL_FINALLY}, 055 * {@link TokenTypes#LITERAL_FOR LITERAL_FOR}, 056 * {@link TokenTypes#LITERAL_IF LITERAL_IF}, 057 * {@link TokenTypes#LITERAL_RETURN LITERAL_RETURN}, 058 * {@link TokenTypes#LITERAL_SWITCH LITERAL_SWITCH}, 059 * {@link TokenTypes#LITERAL_SYNCHRONIZED LITERAL_SYNCHRONIZED}, 060 * {@link TokenTypes#LITERAL_TRY LITERAL_TRY}, 061 * {@link TokenTypes#LITERAL_WHILE LITERAL_WHILE}, 062 * {@link TokenTypes#LOR LOR}, 063 * {@link TokenTypes#LT LT}, 064 * {@link TokenTypes#MINUS MINUS}, 065 * {@link TokenTypes#MINUS_ASSIGN MINUS_ASSIGN}, 066 * {@link TokenTypes#MOD MOD}, 067 * {@link TokenTypes#MOD_ASSIGN MOD_ASSIGN}, 068 * {@link TokenTypes#NOT_EQUAL NOT_EQUAL}, 069 * {@link TokenTypes#PLUS PLUS}, 070 * {@link TokenTypes#PLUS_ASSIGN PLUS_ASSIGN}, 071 * {@link TokenTypes#QUESTION QUESTION}, 072 * {@link TokenTypes#RCURLY RCURLY}, 073 * {@link TokenTypes#SL SL}, 074 * {@link TokenTypes#SLIST SLIST}, 075 * {@link TokenTypes#SL_ASSIGN SL_ASSIGN}, 076 * {@link TokenTypes#SR SR}, 077 * {@link TokenTypes#SR_ASSIGN SR_ASSIGN}, 078 * {@link TokenTypes#STAR STAR}, 079 * {@link TokenTypes#STAR_ASSIGN STAR_ASSIGN}, 080 * {@link TokenTypes#LITERAL_ASSERT LITERAL_ASSERT}, 081 * {@link TokenTypes#TYPE_EXTENSION_AND TYPE_EXTENSION_AND}. 082 * 083 * <p>An example of how to configure the check is: 084 * 085 * <pre> 086 * <module name="WhitespaceAround"/> 087 * </pre> 088 * 089 * <p>An example of how to configure the check for whitespace only around 090 * assignment operators is: 091 * 092 * <pre> 093 * <module name="WhitespaceAround"> 094 * <property name="tokens" 095 * value="ASSIGN,DIV_ASSIGN,PLUS_ASSIGN,MINUS_ASSIGN,STAR_ASSIGN, 096 * MOD_ASSIGN,SR_ASSIGN,BSR_ASSIGN,SL_ASSIGN,BXOR_ASSIGN, 097 * BOR_ASSIGN,BAND_ASSIGN"/> 098 * </module> 099 * </pre> 100 * 101 * <p>An example of how to configure the check for whitespace only around 102 * curly braces is: 103 * <pre> 104 * <module name="WhitespaceAround"> 105 * <property name="tokens" 106 * value="LCURLY,RCURLY"/> 107 * </module> 108 * </pre> 109 * 110 * <p>In addition, this check can be configured to allow empty methods, types, 111 * for, while, do-while loops, lambdas and constructor bodies. 112 * For example: 113 * 114 * <pre>{@code 115 * public MyClass() {} // empty constructor 116 * public void func() {} // empty method 117 * public interface Foo {} // empty interface 118 * public class Foo {} // empty class 119 * public enum Foo {} // empty enum 120 * MyClass c = new MyClass() {}; // empty anonymous class 121 * while (i = 1) {} // empty while loop 122 * for (int i = 1; i > 1; i++) {} // empty for loop 123 * do {} while (i = 1); // empty do-while loop 124 * Runnable noop = () -> {}; // empty lambda 125 * public @interface Beta {} // empty annotation type 126 * }</pre> 127 * 128 * <p>This check does not flag as violation double brace initialization like:</p> 129 * <pre> 130 * new Properties() {{ 131 * setProperty("key", "value"); 132 * }}; 133 * </pre> 134 * 135 * <p>To configure the check to allow empty method blocks use 136 * 137 * <pre> <property name="allowEmptyMethods" value="true" /></pre> 138 * 139 * <p>To configure the check to allow empty constructor blocks use 140 * 141 * <pre> <property name="allowEmptyConstructors" value="true" /></pre> 142 * 143 * <p>To configure the check to allow empty type blocks use 144 * 145 * <pre> <property name="allowEmptyTypes" value="true" /></pre> 146 * 147 * <p>To configure the check to allow empty loop blocks use 148 * 149 * <pre> <property name="allowEmptyLoops" value="true" /></pre> 150 * 151 * <p>To configure the check to allow empty lambdas blocks use 152 * 153 * <pre> <property name="allowEmptyLambdas" value="true" /></pre> 154 * 155 * <p>Also, this check can be configured to ignore the colon in an enhanced for 156 * loop. The colon in an enhanced for loop is ignored by default 157 * 158 * <p>To configure the check to ignore the colon 159 * 160 * <pre> <property name="ignoreEnhancedForColon" value="true" /></pre> 161 * 162 * @author Oliver Burn 163 * @author maxvetrenko 164 * @author Andrei Selkin 165 */ 166public class WhitespaceAroundCheck extends AbstractCheck { 167 168 /** 169 * A key is pointing to the warning message text in "messages.properties" 170 * file. 171 */ 172 public static final String MSG_WS_NOT_PRECEDED = "ws.notPreceded"; 173 174 /** 175 * A key is pointing to the warning message text in "messages.properties" 176 * file. 177 */ 178 public static final String MSG_WS_NOT_FOLLOWED = "ws.notFollowed"; 179 180 /** Whether or not empty constructor bodies are allowed. */ 181 private boolean allowEmptyConstructors; 182 /** Whether or not empty method bodies are allowed. */ 183 private boolean allowEmptyMethods; 184 /** Whether or not empty classes, enums and interfaces are allowed. */ 185 private boolean allowEmptyTypes; 186 /** Whether or not empty loops are allowed. */ 187 private boolean allowEmptyLoops; 188 /** Whether or not empty lambda blocks are allowed. */ 189 private boolean allowEmptyLambdas; 190 /** Whether or not to ignore a colon in a enhanced for loop. */ 191 private boolean ignoreEnhancedForColon = true; 192 193 @Override 194 public int[] getDefaultTokens() { 195 return new int[] { 196 TokenTypes.ASSIGN, 197 TokenTypes.BAND, 198 TokenTypes.BAND_ASSIGN, 199 TokenTypes.BOR, 200 TokenTypes.BOR_ASSIGN, 201 TokenTypes.BSR, 202 TokenTypes.BSR_ASSIGN, 203 TokenTypes.BXOR, 204 TokenTypes.BXOR_ASSIGN, 205 TokenTypes.COLON, 206 TokenTypes.DIV, 207 TokenTypes.DIV_ASSIGN, 208 TokenTypes.DO_WHILE, 209 TokenTypes.EQUAL, 210 TokenTypes.GE, 211 TokenTypes.GT, 212 TokenTypes.LAMBDA, 213 TokenTypes.LAND, 214 TokenTypes.LCURLY, 215 TokenTypes.LE, 216 TokenTypes.LITERAL_CATCH, 217 TokenTypes.LITERAL_DO, 218 TokenTypes.LITERAL_ELSE, 219 TokenTypes.LITERAL_FINALLY, 220 TokenTypes.LITERAL_FOR, 221 TokenTypes.LITERAL_IF, 222 TokenTypes.LITERAL_RETURN, 223 TokenTypes.LITERAL_SWITCH, 224 TokenTypes.LITERAL_SYNCHRONIZED, 225 TokenTypes.LITERAL_TRY, 226 TokenTypes.LITERAL_WHILE, 227 TokenTypes.LOR, 228 TokenTypes.LT, 229 TokenTypes.MINUS, 230 TokenTypes.MINUS_ASSIGN, 231 TokenTypes.MOD, 232 TokenTypes.MOD_ASSIGN, 233 TokenTypes.NOT_EQUAL, 234 TokenTypes.PLUS, 235 TokenTypes.PLUS_ASSIGN, 236 TokenTypes.QUESTION, 237 TokenTypes.RCURLY, 238 TokenTypes.SL, 239 TokenTypes.SLIST, 240 TokenTypes.SL_ASSIGN, 241 TokenTypes.SR, 242 TokenTypes.SR_ASSIGN, 243 TokenTypes.STAR, 244 TokenTypes.STAR_ASSIGN, 245 TokenTypes.LITERAL_ASSERT, 246 TokenTypes.TYPE_EXTENSION_AND, 247 }; 248 } 249 250 @Override 251 public int[] getAcceptableTokens() { 252 return new int[] { 253 TokenTypes.ASSIGN, 254 TokenTypes.ARRAY_INIT, 255 TokenTypes.BAND, 256 TokenTypes.BAND_ASSIGN, 257 TokenTypes.BOR, 258 TokenTypes.BOR_ASSIGN, 259 TokenTypes.BSR, 260 TokenTypes.BSR_ASSIGN, 261 TokenTypes.BXOR, 262 TokenTypes.BXOR_ASSIGN, 263 TokenTypes.COLON, 264 TokenTypes.DIV, 265 TokenTypes.DIV_ASSIGN, 266 TokenTypes.DO_WHILE, 267 TokenTypes.EQUAL, 268 TokenTypes.GE, 269 TokenTypes.GT, 270 TokenTypes.LAMBDA, 271 TokenTypes.LAND, 272 TokenTypes.LCURLY, 273 TokenTypes.LE, 274 TokenTypes.LITERAL_CATCH, 275 TokenTypes.LITERAL_DO, 276 TokenTypes.LITERAL_ELSE, 277 TokenTypes.LITERAL_FINALLY, 278 TokenTypes.LITERAL_FOR, 279 TokenTypes.LITERAL_IF, 280 TokenTypes.LITERAL_RETURN, 281 TokenTypes.LITERAL_SWITCH, 282 TokenTypes.LITERAL_SYNCHRONIZED, 283 TokenTypes.LITERAL_TRY, 284 TokenTypes.LITERAL_WHILE, 285 TokenTypes.LOR, 286 TokenTypes.LT, 287 TokenTypes.MINUS, 288 TokenTypes.MINUS_ASSIGN, 289 TokenTypes.MOD, 290 TokenTypes.MOD_ASSIGN, 291 TokenTypes.NOT_EQUAL, 292 TokenTypes.PLUS, 293 TokenTypes.PLUS_ASSIGN, 294 TokenTypes.QUESTION, 295 TokenTypes.RCURLY, 296 TokenTypes.SL, 297 TokenTypes.SLIST, 298 TokenTypes.SL_ASSIGN, 299 TokenTypes.SR, 300 TokenTypes.SR_ASSIGN, 301 TokenTypes.STAR, 302 TokenTypes.STAR_ASSIGN, 303 TokenTypes.LITERAL_ASSERT, 304 TokenTypes.TYPE_EXTENSION_AND, 305 TokenTypes.WILDCARD_TYPE, 306 TokenTypes.GENERIC_START, 307 TokenTypes.GENERIC_END, 308 }; 309 } 310 311 @Override 312 public int[] getRequiredTokens() { 313 return CommonUtils.EMPTY_INT_ARRAY; 314 } 315 316 /** 317 * Sets whether or not empty method bodies are allowed. 318 * @param allow {@code true} to allow empty method bodies. 319 */ 320 public void setAllowEmptyMethods(boolean allow) { 321 allowEmptyMethods = allow; 322 } 323 324 /** 325 * Sets whether or not empty constructor bodies are allowed. 326 * @param allow {@code true} to allow empty constructor bodies. 327 */ 328 public void setAllowEmptyConstructors(boolean allow) { 329 allowEmptyConstructors = allow; 330 } 331 332 /** 333 * Sets whether or not to ignore the whitespace around the 334 * colon in an enhanced for loop. 335 * @param ignore {@code true} to ignore enhanced for colon. 336 */ 337 public void setIgnoreEnhancedForColon(boolean ignore) { 338 ignoreEnhancedForColon = ignore; 339 } 340 341 /** 342 * Sets whether or not empty type bodies are allowed. 343 * @param allow {@code true} to allow empty type bodies. 344 */ 345 public void setAllowEmptyTypes(boolean allow) { 346 allowEmptyTypes = allow; 347 } 348 349 /** 350 * Sets whether or not empty loop bodies are allowed. 351 * @param allow {@code true} to allow empty loops bodies. 352 */ 353 public void setAllowEmptyLoops(boolean allow) { 354 allowEmptyLoops = allow; 355 } 356 357 /** 358 * Sets whether or not empty lambdas bodies are allowed. 359 * @param allow {@code true} to allow empty lambda expressions. 360 */ 361 public void setAllowEmptyLambdas(boolean allow) { 362 allowEmptyLambdas = allow; 363 } 364 365 @Override 366 public void visitToken(DetailAST ast) { 367 final int currentType = ast.getType(); 368 if (!isNotRelevantSituation(ast, currentType)) { 369 final String line = getLine(ast.getLineNo() - 1); 370 final int before = ast.getColumnNo() - 1; 371 final int after = ast.getColumnNo() + ast.getText().length(); 372 373 if (before >= 0) { 374 final char prevChar = line.charAt(before); 375 if (shouldCheckSeparationFromPreviousToken(ast) 376 && !Character.isWhitespace(prevChar)) { 377 log(ast.getLineNo(), ast.getColumnNo(), 378 MSG_WS_NOT_PRECEDED, ast.getText()); 379 } 380 } 381 382 if (after < line.length()) { 383 final char nextChar = line.charAt(after); 384 if (shouldCheckSeparationFromNextToken(ast, nextChar) 385 && !Character.isWhitespace(nextChar)) { 386 log(ast.getLineNo(), ast.getColumnNo() + ast.getText().length(), 387 MSG_WS_NOT_FOLLOWED, ast.getText()); 388 } 389 } 390 } 391 } 392 393 /** 394 * Is ast not a target of Check. 395 * @param ast ast 396 * @param currentType type of ast 397 * @return true is ok to skip validation 398 */ 399 private boolean isNotRelevantSituation(DetailAST ast, int currentType) { 400 final int parentType = ast.getParent().getType(); 401 final boolean starImport = currentType == TokenTypes.STAR 402 && parentType == TokenTypes.DOT; 403 final boolean slistInsideCaseGroup = currentType == TokenTypes.SLIST 404 && parentType == TokenTypes.CASE_GROUP; 405 406 final boolean starImportOrSlistInsideCaseGroup = starImport || slistInsideCaseGroup; 407 final boolean colonOfCaseOrDefaultOrForEach = 408 isColonOfCaseOrDefault(currentType, parentType) 409 || isColonOfForEach(currentType, parentType); 410 final boolean emptyBlockOrType = 411 isEmptyBlock(ast, parentType) 412 || allowEmptyTypes && isEmptyType(ast); 413 414 return starImportOrSlistInsideCaseGroup 415 || colonOfCaseOrDefaultOrForEach 416 || emptyBlockOrType 417 || isArrayInitialization(currentType, parentType); 418 } 419 420 /** 421 * Check if it should be checked if previous token is separated from current by 422 * whitespace. 423 * This function is needed to recognise double brace initialization as valid, 424 * unfortunately its not possible to implement this functionality 425 * in isNotRelevantSituation method, because in this method when we return 426 * true(is not relevant) ast is later doesnt check at all. For example: 427 * new Properties() {{setProperty("double curly braces", "are not a style error"); 428 * }}; 429 * For second left curly brace in first line when we would return true from 430 * isNotRelevantSituation it wouldn't later check that the next token(setProperty) 431 * is not separated from previous token. 432 * @param ast current AST. 433 * @return true if it should be checked if previous token is separated by whitespace, 434 * false otherwise. 435 */ 436 private static boolean shouldCheckSeparationFromPreviousToken(DetailAST ast) { 437 return !isPartOfDoubleBraceInitializerForPreviousToken(ast); 438 } 439 440 /** 441 * Check if it should be checked if next token is separated from current by 442 * whitespace. Explanation why this method is needed is identical to one 443 * included in shouldCheckSeparationFromPreviousToken method. 444 * @param ast current AST. 445 * @param nextChar next character. 446 * @return true if it should be checked if next token is separated by whitespace, 447 * false otherwise. 448 */ 449 private static boolean shouldCheckSeparationFromNextToken(DetailAST ast, char nextChar) { 450 return !(ast.getType() == TokenTypes.LITERAL_RETURN 451 && ast.getFirstChild().getType() == TokenTypes.SEMI) 452 && ast.getType() != TokenTypes.ARRAY_INIT 453 && !isAnonymousInnerClassEnd(ast.getType(), nextChar) 454 && !isPartOfDoubleBraceInitializerForNextToken(ast); 455 } 456 457 /** 458 * Check for "})" or "};" or "},". Happens with anon-inners 459 * @param currentType token 460 * @param nextChar next symbol 461 * @return true is that is end of anon inner class 462 */ 463 private static boolean isAnonymousInnerClassEnd(int currentType, char nextChar) { 464 return currentType == TokenTypes.RCURLY 465 && (nextChar == ')' 466 || nextChar == ';' 467 || nextChar == ',' 468 || nextChar == '.'); 469 } 470 471 /** 472 * Is empty block. 473 * @param ast ast 474 * @param parentType parent 475 * @return true is block is empty 476 */ 477 private boolean isEmptyBlock(DetailAST ast, int parentType) { 478 return isEmptyMethodBlock(ast, parentType) 479 || isEmptyCtorBlock(ast, parentType) 480 || isEmptyLoop(ast, parentType) 481 || isEmptyLambda(ast, parentType); 482 } 483 484 /** 485 * Tests if a given {@code DetailAST} is part of an empty block. 486 * An example empty block might look like the following 487 * <p> 488 * <pre> public void myMethod(int val) {}</pre> 489 * </p> 490 * In the above, the method body is an empty block ("{}"). 491 * 492 * @param ast the {@code DetailAST} to test. 493 * @param parentType the token type of {@code ast}'s parent. 494 * @param match the parent token type we're looking to match. 495 * @return {@code true} if {@code ast} makes up part of an 496 * empty block contained under a {@code match} token type 497 * node. 498 */ 499 private static boolean isEmptyBlock(DetailAST ast, int parentType, int match) { 500 final int type = ast.getType(); 501 if (type == TokenTypes.RCURLY) { 502 final DetailAST parent = ast.getParent(); 503 final DetailAST grandParent = ast.getParent().getParent(); 504 return parentType == TokenTypes.SLIST 505 && parent.getFirstChild().getType() == TokenTypes.RCURLY 506 && grandParent.getType() == match; 507 } 508 509 return type == TokenTypes.SLIST 510 && parentType == match 511 && ast.getFirstChild().getType() == TokenTypes.RCURLY; 512 } 513 514 /** 515 * Whether colon belongs to cases or defaults. 516 * @param currentType current 517 * @param parentType parent 518 * @return true if current token in colon of case or default tokens 519 */ 520 private static boolean isColonOfCaseOrDefault(int currentType, int parentType) { 521 return currentType == TokenTypes.COLON 522 && (parentType == TokenTypes.LITERAL_DEFAULT 523 || parentType == TokenTypes.LITERAL_CASE); 524 } 525 526 /** 527 * Whether colon belongs to for-each. 528 * @param currentType current 529 * @param parentType parent 530 * @return true if current token in colon of for-each token 531 */ 532 private boolean isColonOfForEach(int currentType, int parentType) { 533 return currentType == TokenTypes.COLON 534 && parentType == TokenTypes.FOR_EACH_CLAUSE 535 && ignoreEnhancedForColon; 536 } 537 538 /** 539 * Is array initialization. 540 * @param currentType current token 541 * @param parentType parent token 542 * @return true is current token inside array initialization 543 */ 544 private static boolean isArrayInitialization(int currentType, int parentType) { 545 return (currentType == TokenTypes.RCURLY || currentType == TokenTypes.LCURLY) 546 && (parentType == TokenTypes.ARRAY_INIT 547 || parentType == TokenTypes.ANNOTATION_ARRAY_INIT); 548 } 549 550 /** 551 * Test if the given {@code DetailAST} is part of an allowed empty 552 * method block. 553 * @param ast the {@code DetailAST} to test. 554 * @param parentType the token type of {@code ast}'s parent. 555 * @return {@code true} if {@code ast} makes up part of an 556 * allowed empty method block. 557 */ 558 private boolean isEmptyMethodBlock(DetailAST ast, int parentType) { 559 return allowEmptyMethods 560 && isEmptyBlock(ast, parentType, TokenTypes.METHOD_DEF); 561 } 562 563 /** 564 * Test if the given {@code DetailAST} is part of an allowed empty 565 * constructor (ctor) block. 566 * @param ast the {@code DetailAST} to test. 567 * @param parentType the token type of {@code ast}'s parent. 568 * @return {@code true} if {@code ast} makes up part of an 569 * allowed empty constructor block. 570 */ 571 private boolean isEmptyCtorBlock(DetailAST ast, int parentType) { 572 return allowEmptyConstructors 573 && isEmptyBlock(ast, parentType, TokenTypes.CTOR_DEF); 574 } 575 576 /** 577 * 578 * @param ast ast the {@code DetailAST} to test. 579 * @param parentType the token type of {@code ast}'s parent. 580 * @return {@code true} if {@code ast} makes up part of an 581 * allowed empty loop block. 582 */ 583 private boolean isEmptyLoop(DetailAST ast, int parentType) { 584 return allowEmptyLoops 585 && (isEmptyBlock(ast, parentType, TokenTypes.LITERAL_FOR) 586 || isEmptyBlock(ast, parentType, TokenTypes.LITERAL_WHILE) 587 || isEmptyBlock(ast, parentType, TokenTypes.LITERAL_DO)); 588 } 589 590 /** 591 * Test if the given {@code DetailAST} is part of an allowed empty 592 * lambda block. 593 * @param ast the {@code DetailAST} to test. 594 * @param parentType the token type of {@code ast}'s parent. 595 * @return {@code true} if {@code ast} makes up part of an 596 * allowed empty lambda block. 597 */ 598 private boolean isEmptyLambda(DetailAST ast, int parentType) { 599 return allowEmptyLambdas && isEmptyBlock(ast, parentType, TokenTypes.LAMBDA); 600 } 601 602 /** 603 * Test if the given {@code DetailAST} is part of an empty block. 604 * An example empty block might look like the following 605 * <p> 606 * <pre> class Foo {}</pre> 607 * </p> 608 * 609 * @param ast ast the {@code DetailAST} to test. 610 * @return {@code true} if {@code ast} makes up part of an 611 * empty block contained under a {@code match} token type 612 * node. 613 */ 614 private static boolean isEmptyType(DetailAST ast) { 615 final int type = ast.getType(); 616 final DetailAST nextSibling = ast.getNextSibling(); 617 final DetailAST previousSibling = ast.getPreviousSibling(); 618 return type == TokenTypes.LCURLY 619 && nextSibling.getType() == TokenTypes.RCURLY 620 || type == TokenTypes.RCURLY 621 && previousSibling != null 622 && previousSibling.getType() == TokenTypes.LCURLY; 623 } 624 625 /** 626 * Check if given ast is part of double brace initializer and if it 627 * should omit checking if previous token is separated by whitespace. 628 * @param ast ast to check 629 * @return true if it should omit checking for previous token, false otherwise 630 */ 631 private static boolean isPartOfDoubleBraceInitializerForPreviousToken(DetailAST ast) { 632 final boolean initializerBeginsAfterClassBegins = ast.getType() == TokenTypes.SLIST 633 && ast.getParent().getType() == TokenTypes.INSTANCE_INIT; 634 final boolean classEndsAfterInitializerEnds = ast.getType() == TokenTypes.RCURLY 635 && ast.getPreviousSibling() != null 636 && ast.getPreviousSibling().getType() == TokenTypes.INSTANCE_INIT; 637 return initializerBeginsAfterClassBegins || classEndsAfterInitializerEnds; 638 } 639 640 /** 641 * Check if given ast is part of double brace initializer and if it 642 * should omit checking if next token is separated by whitespace. 643 * See <a href="https://github.com/checkstyle/checkstyle/pull/2845"> 644 * PR#2845</a> for more information why this function was needed. 645 * @param ast ast to check 646 * @return true if it should omit checking for next token, false otherwise 647 */ 648 private static boolean isPartOfDoubleBraceInitializerForNextToken(DetailAST ast) { 649 final boolean classBeginBeforeInitializerBegin = ast.getType() == TokenTypes.LCURLY 650 && ast.getNextSibling().getType() == TokenTypes.INSTANCE_INIT; 651 final boolean initalizerEndsBeforeClassEnds = ast.getType() == TokenTypes.RCURLY 652 && ast.getParent().getType() == TokenTypes.SLIST 653 && ast.getParent().getParent().getType() == TokenTypes.INSTANCE_INIT 654 && ast.getParent().getParent().getNextSibling().getType() == TokenTypes.RCURLY; 655 return classBeginBeforeInitializerBegin || initalizerEndsBeforeClassEnds; 656 } 657}