Class CatchParameterNameCheck

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