Package com.puppycrawl.tools.checkstyle.checks.coding

Class FallThroughCheck

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.coding.FallThroughCheck
All Implemented Interfaces:
Configurable, Contextualizable
public class FallThroughCheck extends AbstractCheck
Checks for fall-through in switch statements. Finds locations where a case contains Java code but lacks a break, return, yield, throw or continue statement.

The check honors special comments to suppress the warning. By default, the texts "fallthru", "fall thru", "fall-thru", "fallthrough", "fall through", "fall-through" "fallsthrough", "falls through", "falls-through" (case-sensitive). The comment containing these words must be all on one line, and must be on the last non-empty line before the case triggering the warning or on the same line before the case(ugly, but possible). Any other comment may follow on the same line.

Note: The check assumes that there is no unreachable code in the case.

Since:
3.4

  • 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:

    • 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:

    • 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:

    • isCommentNodesRequired

      public boolean isCommentNodesRequired()
      Description copied from class: AbstractCheck
      Whether comment nodes are required or not.
      Overrides:
      isCommentNodesRequired in class AbstractCheck
      Returns:
      false as a default value.

    • setReliefPattern

      public void setReliefPattern(Pattern pattern)
      Setter to define the RegExp to match the relief comment that suppresses the warning about a fall through.
      Parameters:
      pattern - The regular expression pattern.
      Since:
      4.0

    • setCheckLastCaseGroup

      public void setCheckLastCaseGroup(boolean value)
      Setter to control whether the last case group must be checked.
      Parameters:
      value - new value of the property.
      Since:
      4.0

    • 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

    • hasFallThroughComment

      private boolean hasFallThroughComment(DetailAST currentCase)
      Determines if the fall through case between currentCase and nextCase is relieved by an appropriate comment.

      Handles

       case 1:
 /* FALLTHRU */ case 2:

 switch(i) {
 default:
 /* FALLTHRU */}

 case 1:
 // FALLTHRU
 case 2:

 switch(i) {
 default:
 // FALLTHRU
      Parameters:
      currentCase - AST of the case that falls through to the next case.
      Returns:
      True if a relief comment was found

    • hasReliefComment

      private boolean hasReliefComment(DetailAST ast)
      Check if there is any fall through comment.
      Parameters:
      ast - ast to check
      Returns:
      true if relief comment found