Package com.puppycrawl.tools.checkstyle.checks.naming

Class CatchParameterNameCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable
    public class CatchParameterNameCheck
extends AbstractNameCheck

    Checks that catch parameter names conform to a specified pattern.

    Default pattern has the following characteristic:

    • allows names beginning with two lowercase letters followed by at least one uppercase or lowercase letter
    • allows e abbreviation (suitable for exceptions end errors)
    • allows ex abbreviation (suitable for exceptions)
    • allows t abbreviation (suitable for throwables)
    • prohibits numbered abbreviations like e1 or t2
    • prohibits one letter prefixes like pException
    • prohibits two letter abbreviations like ie or ee
    • prohibits any other characters than letters
    • Property format - Specifies valid identifiers. Type is java.util.regex.Pattern. Default value is "^(e|t|ex|[a-z][a-z][a-zA-Z]+)$".

    To configure the check: 

     <module name="CatchParameterName"/>

    Example:

     public class MyTest {
   public void myTest() {
     try {
       // ...
     } catch (ArithmeticException e) { // OK
       // ...
     } catch (ArrayIndexOutOfBoundsException ex) { // OK
       // ...
     } catch (Throwable t) { // OK
       // ...
     } catch (IndexOutOfBoundsException e123) { // violation, digits
                                // not allowed
       // ...
     } catch (NullPointerException ab) { // violation, should have at least
                              // three characters if not e|t|ex
       // ...
     } catch (ArrayStoreException abc) { // OK
       // ...
     } catch (InterruptedException aBC) { // violation, first two characters
                               // should be in lowercase
       // ...
     } catch (RuntimeException abC) { // OK
       // ...
     } catch (Exception abCD) { // OK
       // ...
     }
   }
 }

    An example of how to configure the check for names that begin with a lower case letter, followed by any letters or digits is:

    Configuration:

     <module name="CatchParameterName">
   <property name="format" value="^[a-z][a-zA-Z0-9]+$"/>
 </module>

    Example:

     public class MyTest {
   public void myTest() {
     try {
       // ...
     } catch (ArithmeticException ex) { // OK
       // ...
     } catch (ArrayIndexOutOfBoundsException ex2) { // OK
       // ...
     } catch (IOException thirdException) { // OK
       // ...
     } catch (Exception FourthException) { // violation, the initial letter
                                           // should be lowercase
       // ...
     }
   }
 }

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • name.invalidPattern
    Since:
    6.14

    • Constructor Detail

      • CatchParameterNameCheck

        public CatchParameterNameCheck()
        Creates a new CatchParameterNameCheck instance.

    • Method Detail

      • 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

      • mustCheckName

        protected boolean mustCheckName​(DetailAST ast)
        Description copied from class: AbstractNameCheck
        Decides whether the name of an AST should be checked against the format regexp.
        Specified by:
        mustCheckName in class AbstractNameCheck
        Parameters:
        ast - the AST to check.
        Returns:
        true if the IDENT subnode of ast should be checked against the format regexp.