Package com.puppycrawl.tools.checkstyle.checks.whitespace

Class WhitespaceAroundCheck

java.lang.Object
com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
com.puppycrawl.tools.checkstyle.api.AbstractCheck
com.puppycrawl.tools.checkstyle.checks.whitespace.WhitespaceAroundCheck
All Implemented Interfaces:
Configurable, Contextualizable
public class WhitespaceAroundCheck extends AbstractCheck
Checks that a token is surrounded by whitespace. Empty constructor, method, class, enum, interface, loop bodies (blocks), lambdas of the form 

 public MyClass() {}      // empty constructor
 public void func() {}    // empty method
 public interface Foo {} // empty interface
 public class Foo {} // empty class
 public enum Foo {} // empty enum
 MyClass c = new MyClass() {}; // empty anonymous class
 while (i = 1) {} // empty while loop
 for (int i = 1; i > 1; i++) {} // empty for loop
 do {} while (i = 1); // empty do-while loop
 Runnable noop = () -> {}; // empty lambda
 public @interface Beta {} // empty annotation type

may optionally be exempted from the policy using the allowEmptyMethods, allowEmptyConstructors, allowEmptyTypes, allowEmptyLoops, allowEmptyLambdas, allowEmptyCatches and allowEmptySwitchBlockStatements properties.

This check does not flag as violation double brace initialization like: 


 new Properties() {{
     setProperty("key", "value");
 }};

Parameter allowEmptyCatches allows to suppress violations when token list contains SLIST to check if beginning of block is surrounded by whitespace and catch block is empty, for example: 


 try {
     k = 5 / i;
 } catch (ArithmeticException ex) {}

With this property turned off, this raises violation because the beginning of the catch block (left curly bracket) is not separated from the end of the catch block (right curly bracket).

Note: Switch expressions are ignored by this check.

Since:
3.0

  • Field Details

  • Constructor Details

  • Method Details

    • getDefaultTokens

      public int[] getDefaultTokens()
      Description copied from class: AbstractCheck
      Returns the default token a check is interested in. Only used if the configuration for a check does not define the tokens.
      Specified by:
      getDefaultTokens in class AbstractCheck
      Returns:
      the default tokens
      See Also:

    • getAcceptableTokens

      public int[] getAcceptableTokens()
      Description copied from class: AbstractCheck
      The configurable token set. Used to protect Checks against malicious users who specify an unacceptable token set in the configuration file. The default implementation returns the check's default tokens.
      Specified by:
      getAcceptableTokens in class AbstractCheck
      Returns:
      the token set this check is designed for.
      See Also:

    • getRequiredTokens

      public int[] getRequiredTokens()
      Description copied from class: AbstractCheck
      The tokens that this check must be registered for.
      Specified by:
      getRequiredTokens in class AbstractCheck
      Returns:
      the token set this must be registered for.
      See Also:

    • setAllowEmptyMethods

      public void setAllowEmptyMethods(boolean allow)
      Setter to allow empty method bodies.
      Parameters:
      allow - true to allow empty method bodies.
      Since:
      4.0

    • setAllowEmptyConstructors

      public void setAllowEmptyConstructors(boolean allow)
      Setter to allow empty constructor bodies.
      Parameters:
      allow - true to allow empty constructor bodies.
      Since:
      4.0

    • setIgnoreEnhancedForColon

      public void setIgnoreEnhancedForColon(boolean ignore)
      Setter to ignore whitespace around colon in enhanced for loop.
      Parameters:
      ignore - true to ignore enhanced for colon.
      Since:
      5.5

    • setAllowEmptyTypes

      public void setAllowEmptyTypes(boolean allow)
      Setter to allow empty class, interface and enum bodies.
      Parameters:
      allow - true to allow empty type bodies.
      Since:
      5.8

    • setAllowEmptyLoops

      public void setAllowEmptyLoops(boolean allow)
      Setter to allow empty loop bodies.
      Parameters:
      allow - true to allow empty loops bodies.
      Since:
      5.8

    • setAllowEmptyLambdas

      public void setAllowEmptyLambdas(boolean allow)
      Setter to allow empty lambda bodies.
      Parameters:
      allow - true to allow empty lambda expressions.
      Since:
      6.14

    • setAllowEmptyCatches

      public void setAllowEmptyCatches(boolean allow)
      Setter to allow empty catch bodies.
      Parameters:
      allow - true to allow empty catch blocks.
      Since:
      7.6

    • setAllowEmptySwitchBlockStatements

      public void setAllowEmptySwitchBlockStatements(boolean allow)
      Setter to allow empty switch blocks and block statements.
      Parameters:
      allow - true to allow empty switch case and default blocks.
      Since:
      10.19.0

    • visitToken

      public void visitToken(DetailAST ast)
      Description copied from class: AbstractCheck
      Called to process a token.
      Overrides:
      visitToken in class AbstractCheck
      Parameters:
      ast - the token to process

    • isNotRelevantSituation

      private boolean isNotRelevantSituation(DetailAST ast, int currentType)
      Is ast not a target of Check.
      Parameters:
      ast - ast
      currentType - type of ast
      Returns:
      true is ok to skip validation

    • shouldCheckSeparationFromPreviousToken

      private static boolean shouldCheckSeparationFromPreviousToken(DetailAST ast)
      Check if it should be checked if previous token is separated from current by whitespace. This function is needed to recognise double brace initialization as valid, unfortunately it's not possible to implement this functionality in isNotRelevantSituation method, because in this method when we return true(is not relevant) ast is later doesn't check at all. For example: new Properties() {{setProperty("double curly braces", "are not a style violation"); }}; For second left curly brace in first line when we would return true from isNotRelevantSituation it wouldn't later check that the next token(setProperty) is not separated from previous token.
      Parameters:
      ast - current AST.
      Returns:
      true if it should be checked if previous token is separated by whitespace, false otherwise.

    • shouldCheckSeparationFromNextToken

      private boolean shouldCheckSeparationFromNextToken(DetailAST ast, char nextChar)
      Check if it should be checked if next token is separated from current by whitespace. Explanation why this method is needed is identical to one included in shouldCheckSeparationFromPreviousToken method.
      Parameters:
      ast - current AST.
      nextChar - next character.
      Returns:
      true if it should be checked if next token is separated by whitespace, false otherwise.

    • isAnonymousInnerClassEnd

      private static boolean isAnonymousInnerClassEnd(int currentType, char nextChar)
      Check for "})" or "};" or "},". Happens with anon-inners
      Parameters:
      currentType - token
      nextChar - next symbol
      Returns:
      true is that is end of anon inner class

    • isEmptyBlock

      private boolean isEmptyBlock(DetailAST ast, int parentType)
      Is empty block.
      Parameters:
      ast - ast
      parentType - parent
      Returns:
      true is block is empty

    • isEmptyBlock

      private static boolean isEmptyBlock(DetailAST ast, int parentType, int match)
      Tests if a given DetailAST is part of an empty block. An example empty block might look like the following 
         public void myMethod(int val) {}
      In the above, the method body is an empty block ("{}").
      Parameters:
      ast - the DetailAST to test.
      parentType - the token type of ast's parent.
      match - the parent token type we're looking to match.
      Returns:
      true if ast makes up part of an empty block contained under a match token type node.

    • isEmptyMethodBlock

      private boolean isEmptyMethodBlock(DetailAST ast, int parentType)
      Test if the given DetailAST is part of an allowed empty method block.
      Parameters:
      ast - the DetailAST to test.
      parentType - the token type of ast's parent.
      Returns:
      true if ast makes up part of an allowed empty method block.

    • isEmptyCtorBlockCheckedFromRcurly

      private boolean isEmptyCtorBlockCheckedFromRcurly(DetailAST ast)
      Test if the given DetailAST is part of an allowed empty constructor (ctor) block checked from RCURLY.
      Parameters:
      ast - the DetailAST to test.
      Returns:
      true if ast makes up part of an allowed empty constructor block.

    • isEmptyCtorBlockCheckedFromSlist

      private boolean isEmptyCtorBlockCheckedFromSlist(DetailAST ast)
      Test if the given DetailAST is a part of an allowed empty constructor checked from SLIST token.
      Parameters:
      ast - the DetailAST to test.
      Returns:
      true if ast makes up part of an empty constructor block.

    • isEmptyLoop

      private boolean isEmptyLoop(DetailAST ast, int parentType)
      Checks if loop is empty.
      Parameters:
      ast - ast the DetailAST to test.
      parentType - the token type of ast's parent.
      Returns:
      true if ast makes up part of an allowed empty loop block.

    • isEmptyLambda

      private boolean isEmptyLambda(DetailAST ast, int parentType)
      Test if the given DetailAST is part of an allowed empty lambda block.
      Parameters:
      ast - the DetailAST to test.
      parentType - the token type of ast's parent.
      Returns:
      true if ast makes up part of an allowed empty lambda block.

    • isEmptyCatch

      private boolean isEmptyCatch(DetailAST ast, int parentType)
      Tests if the given DetailAst is part of an allowed empty catch block.
      Parameters:
      ast - the DetailAst to test.
      parentType - the token type of ast's parent
      Returns:
      true if ast makes up part of an allowed empty catch block.

    • isEmptySwitchBlockStatement

      private boolean isEmptySwitchBlockStatement(DetailAST ast)
      Tests if the given DetailAst is part of an allowed empty switch case or default block.
      Parameters:
      ast - the DetailAst to test.
      Returns:
      true if ast makes up part of an allowed empty switch case or default block.

    • isEmptyType

      private static boolean isEmptyType(DetailAST ast)
      Test if the given DetailAST is part of an empty block. An example empty block might look like the following 
         class Foo {}
      Parameters:
      ast - ast the DetailAST to test.
      Returns:
      true if ast makes up part of an empty block contained under a match token type node.

    • isPartOfDoubleBraceInitializerForPreviousToken

      private static boolean isPartOfDoubleBraceInitializerForPreviousToken(DetailAST ast)
      Check if given ast is part of double brace initializer and if it should omit checking if previous token is separated by whitespace.
      Parameters:
      ast - ast to check
      Returns:
      true if it should omit checking for previous token, false otherwise

    • isPartOfDoubleBraceInitializerForNextToken

      private static boolean isPartOfDoubleBraceInitializerForNextToken(DetailAST ast)
      Check if given ast is part of double brace initializer and if it should omit checking if next token is separated by whitespace. See PR#2845 for more information why this function was needed.
      Parameters:
      ast - ast to check
      Returns:
      true if it should omit checking for next token, false otherwise