com.puppycrawl.tools.checkstyle.checks.design
Class DesignForExtensionCheck

java.lang.Object
  com.puppycrawl.tools.checkstyle.api.AutomaticBean
      com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
          com.puppycrawl.tools.checkstyle.api.Check
              com.puppycrawl.tools.checkstyle.checks.design.DesignForExtensionCheck

All Implemented Interfaces:

Configurable, Contextualizable

public class DesignForExtensionCheck

extends Check

Checks that classes are designed for inheritance.

More specifically, it enforces a programming style where superclasses provide empty "hooks" that can be implemented by subclasses.

The exact rule is that nonprivate, nonstatic methods in nonfinal classes (or classes that do not only have private constructors) must either be

• abstract or
• final or
• have an empty implementation

This protects superclasses against beeing broken by subclasses. The downside is that subclasses are limited in their flexibility, in particular they cannot prevent execution of code in the superclass, but that also means that subclasses can't forget to call their super method.

Version:

$Revision: 1.7 $

Author:

lkuehne

Constructor Summary

DesignForExtensionCheck()

Method Summary

int[]	getDefaultTokens() Returns the default token a check is interested in.
void	visitToken(DetailAST aAST) Called to process a token.

Methods inherited from class com.puppycrawl.tools.checkstyle.api.Check

beginTree, destroy, finishTree, getAcceptableTokens, getClassLoader, getFileContents, getLines, getRequiredTokens, getTabWidth, getTokenNames, init, leaveToken, log, log, setClassLoader, setFileContents, setMessages, setTabWidth, setTokens

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter

getMessageBundle, getSeverity, getSeverityLevel, log, log, log, log, log, log, log, log, log, setSeverity

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean

configure, contextualize, finishLocalSetup, getConfiguration, setupChild

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DesignForExtensionCheck

public DesignForExtensionCheck()

Method Detail

getDefaultTokens

public int[] getDefaultTokens()

Description copied from class: Check

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 Check

Returns:

the default tokens

See Also:

Check

visitToken

public void visitToken(DetailAST aAST)

Description copied from class: Check

Called to process a token.

Overrides:

visitToken in class Check

Parameters:

aAST - the token to process

See Also:

Check