Package com.puppycrawl.tools.checkstyle.checks.blocks

Class LeftCurlyCheck

java.lang.Object
com.puppycrawl.tools.checkstyle.api.AutomaticBean
com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
com.puppycrawl.tools.checkstyle.api.AbstractCheck
com.puppycrawl.tools.checkstyle.checks.blocks.LeftCurlyCheck
All Implemented Interfaces:
Configurable, Contextualizable
public class LeftCurlyCheck extends AbstractCheck

Checks for the placement of left curly braces ('{') for code blocks.

To configure the check: 

 <module name="LeftCurly"/>
 
 class Test
 { // Violation - '{' should be on the previous line
   private interface TestInterface
   { // Violation - '{' should be on the previous line
   }

   private
   class
   MyClass { // OK
   }

   enum Colors {RED, // OK
     BLUE,
     GREEN;
   }
 }

To configure the check to apply the nl policy to type blocks: 

 <module name="LeftCurly">
   <property name="option" value="nl"/>
   <property name="tokens" value="CLASS_DEF,INTERFACE_DEF"/>
 </module>
 
 class Test
 { // OK
   private interface TestInterface
   { // OK
   }

   private
   class
   MyClass { // Violation - '{' should be on a new line
   }

   enum Colors {RED, // OK
     BLUE,
     GREEN;
   }
 }

An example of how to configure the check to validate enum definitions: 

 <module name="LeftCurly">
   <property name="ignoreEnums" value="false"/>
 </module>
 
 class Test
 { // Violation - '{' should be on the previous line
   private interface TestInterface
   { // Violation - '{' should be on the previous line
   }

   private
   class
   MyClass { // OK
   }

   enum Colors {RED, // Violation - '{' should have line break after
   BLUE,
   GREEN;
   }
 }

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

  • line.break.after
  • line.new
  • line.previous
Since:
3.0

  • Field Details

    • MSG_KEY_LINE_NEW

      public static final String MSG_KEY_LINE_NEW
      A key is pointing to the warning message text in "messages.properties" file.
      See Also:

    • MSG_KEY_LINE_PREVIOUS

      public static final String MSG_KEY_LINE_PREVIOUS
      A key is pointing to the warning message text in "messages.properties" file.
      See Also:

    • MSG_KEY_LINE_BREAK_AFTER

      public static final String MSG_KEY_LINE_BREAK_AFTER
      A key is pointing to the warning message text in "messages.properties" file.
      See Also:

    • OPEN_CURLY_BRACE

      private static final String OPEN_CURLY_BRACE
      Open curly brace literal.
      See Also:

    • ignoreEnums

      private boolean ignoreEnums
      Allow to ignore enums when left curly brace policy is EOL.

    • option

      private LeftCurlyOption option
      Specify the policy on placement of a left curly brace ('{').

  • Constructor Details

    • LeftCurlyCheck

      public LeftCurlyCheck()

  • Method Details

    • setOption

      public void setOption(String optionStr)
      Setter to specify the policy on placement of a left curly brace ('{').
      Parameters:
      optionStr - string to decode option from
      Throws:
      IllegalArgumentException - if unable to decode

    • setIgnoreEnums

      public void setIgnoreEnums(boolean ignoreEnums)
      Setter to allow to ignore enums when left curly brace policy is EOL.
      Parameters:
      ignoreEnums - check's option for ignoring enums.

    • 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:

    • visitToken

      public void visitToken(DetailAST ast)
      We cannot reduce the number of branches in this switch statement, since many tokens require specific methods to find the first left curly.
      Overrides:
      visitToken in class AbstractCheck
      Parameters:
      ast - the token to process

    • getBraceFromSwitchMember

      private static DetailAST getBraceFromSwitchMember(DetailAST ast)
      Gets the brace of a switch statement/ expression member.
      Parameters:
      ast - DetailAST.
      Returns:
      DetailAST if the first child is TokenTypes.SLIST, null otherwise.

    • getBraceAsFirstChild

      private static DetailAST getBraceAsFirstChild(DetailAST ast)
      Gets a SLIST if it is the first child of the AST.
      Parameters:
      ast - DetailAST.
      Returns:
      DetailAST if the first child is TokenTypes.SLIST, null otherwise.

    • skipModifierAnnotations

      private static DetailAST skipModifierAnnotations(DetailAST ast)
      Skip all TokenTypes.ANNOTATIONs to the first non-annotation.
      Parameters:
      ast - DetailAST.
      Returns:
      DetailAST.

    • findLastAnnotation

      private static DetailAST findLastAnnotation(DetailAST modifiers)
      Find the last token of type TokenTypes.ANNOTATION under the given set of modifiers.
      Parameters:
      modifiers - DetailAST.
      Returns:
      DetailAST or null if there are no annotations.

    • verifyBrace

      private void verifyBrace(DetailAST brace, DetailAST startToken)
      Verifies that a specified left curly brace is placed correctly according to policy.
      Parameters:
      brace - token for left curly brace
      startToken - token for start of expression

    • validateEol

      private void validateEol(DetailAST brace, String braceLine)
      Validate EOL case.
      Parameters:
      brace - brace AST
      braceLine - line content

    • validateNewLinePosition

      private void validateNewLinePosition(DetailAST brace, DetailAST startToken, String braceLine)
      Validate token on new Line position.
      Parameters:
      brace - brace AST
      startToken - start Token
      braceLine - content of line with Brace

    • hasLineBreakAfter

      private boolean hasLineBreakAfter(DetailAST leftCurly)
      Checks if left curly has line break after.
      Parameters:
      leftCurly - Left curly token.
      Returns:
      True, left curly has line break after.