Class 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 Detail

      • MSG_KEY_LINE_NEW

        public static final java.lang.String MSG_KEY_LINE_NEW
        A key is pointing to the warning message text in "messages.properties" file.
        See Also:
        Constant Field Values
      • MSG_KEY_LINE_PREVIOUS

        public static final java.lang.String MSG_KEY_LINE_PREVIOUS
        A key is pointing to the warning message text in "messages.properties" file.
        See Also:
        Constant Field Values
      • MSG_KEY_LINE_BREAK_AFTER

        public static final java.lang.String MSG_KEY_LINE_BREAK_AFTER
        A key is pointing to the warning message text in "messages.properties" file.
        See Also:
        Constant Field Values
      • OPEN_CURLY_BRACE

        private static final java.lang.String OPEN_CURLY_BRACE
        Open curly brace literal.
        See Also:
        Constant Field Values
      • 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 Detail

      • LeftCurlyCheck

        public LeftCurlyCheck()
    • Method Detail

      • setOption

        public void setOption​(java.lang.String optionStr)
        Setter to specify the policy on placement of a left curly brace ('{').
        Parameters:
        optionStr - string to decode option from
        Throws:
        java.lang.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:
        TokenTypes
      • 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:
        TokenTypes
      • 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:
        TokenTypes
      • 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,
                                 java.lang.String braceLine)
        Validate EOL case.
        Parameters:
        brace - brace AST
        braceLine - line content
      • validateNewLinePosition

        private void validateNewLinePosition​(DetailAST brace,
                                             DetailAST startToken,
                                             java.lang.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.