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

Class DefaultComesLastCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable
    public class DefaultComesLastCheck
extends AbstractCheck

    Check that the default is after all the cases in a switch statement.

    Rationale: Java allows default anywhere within the switch statement. But it is more readable if it comes after the last case.

    • Property skipIfLastAndSharedWithCase - Control whether to allow default along with case if they are not last. Type is boolean. Default value is false.

    To configure the check: 

     <module name="DefaultComesLast"/>

    Example:

     switch (i) {
   case 1:
     break;
   case 2:
     break;
   default: // OK
     break;
 }

 switch (i) {
   case 1:
     break;
   case 2:
     break; // OK, no default
 }

 switch (i) {
   case 1:
     break;
   default: // violation, 'default' before 'case'
     break;
   case 2:
     break;
 }

 switch (i) {
   case 1:
   default: // violation, 'default' before 'case'
     break;
   case 2:
     break;
 }

    To configure the check to allow default label to be not last if it is shared with case: 

     <module name="DefaultComesLast">
   <property name="skipIfLastAndSharedWithCase" value="true"/>
 </module>

    Example:

     switch (i) {
   case 1:
     break;
   case 2:
   default: // OK
     break;
   case 3:
     break;
 }

 switch (i) {
   case 1:
     break;
   default: // violation
   case 2:
     break;
 }

 // Switch rules are not subject to fall through, so this is still a violation:
 switch (i) {
   case 1 -> x = 9;
   default -> x = 10; // violation
   case 2 -> x = 32;
 }

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • default.comes.last
    • default.comes.last.in.casegroup
    Since:
    3.4

    • Method Detail

      • 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

      • setSkipIfLastAndSharedWithCase

        public void setSkipIfLastAndSharedWithCase​(boolean newValue)
        Setter to control whether to allow default along with case if they are not last.
        Parameters:
        newValue - whether to ignore checking.

      • findNextSibling

        private static DetailAST findNextSibling​(DetailAST ast,
                                         int tokenType)
        Return token type only if passed tokenType in argument is found or returns -1.
        Parameters:
        ast - root node.
        tokenType - tokentype to be processed.
        Returns:
        token if desired token is found or else null.