com.github.sevntu.checkstyle.checks.coding

Class EmptyPublicCtorInClassCheck

java.lang.Object

com.puppycrawl.tools.checkstyle.api.AutomaticBean

com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter

com.puppycrawl.tools.checkstyle.api.AbstractCheck

com.github.sevntu.checkstyle.checks.coding.EmptyPublicCtorInClassCheck

All Implemented Interfaces:

com.puppycrawl.tools.checkstyle.api.Configurable, com.puppycrawl.tools.checkstyle.api.Contextualizable

public class EmptyPublicCtorInClassCheck
extends com.puppycrawl.tools.checkstyle.api.AbstractCheck

This Check looks for useless empty public constructors. Class constructor is considered useless by this Check if and only if class has exactly one ctor, which is public, empty(one that has no statements) and default.

Example 1. Check will generate violation for this code:

 class Dummy {
     public Dummy() {
     }
 }
 

Example 2. Check will not generate violation for this code:

 class Dummy {
     private Dummy() {
     }
 }
 

class Dummy has only one ctor, which is not public.

Example 3. Check will not generate violation for this code:

 class Dummy {
     public Dummy() {
     }
     public Dummy(int i) {
     }
 }
 

class Dummy has multiple ctors.

Check has two properties:

"classAnnotationNames" - This property contains regex for canonical names of class annotations, which require class to have empty public ctor. Check will not log violations for classes marked with annotations that match this regex. Default option value is "javax\.persistence\.Entity".

"ctorAnnotationNames" - This property contains regex for canonical names of ctor annotations, which make empty public ctor essential. Check will not log violations for ctors marked with annotations that match this regex. Default option value is "com\.google\.inject\.Inject".

Following configuration will adjust Check to skip classes which annotated with "javax.persistence.Entity" and classes which has empty public ctor with "com\.google\.inject\.Inject".

   <module name="EmptyPublicCtorInClassCheck">
     <property name="classAnnotationNames" value="javax\.persistence\.Entity"/>
     <property name="ctorAnnotationNames" value="com\.google\.inject\.Inject"/>
   </module>
 

Since:

1.13.0

Author:

Zuy Alexey

Nested Class Summary

Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean

com.puppycrawl.tools.checkstyle.api.AutomaticBean.OutputStreamOptions

Field Summary

Fields

Modifier and Type	Field and Description
static String	MSG_KEY Violation message key.

Constructor Summary

Constructors

Constructor and Description
EmptyPublicCtorInClassCheck()

Method Summary

Modifier and Type	Method and Description
void	beginTree(com.puppycrawl.tools.checkstyle.api.DetailAST aRootNode)
int[]	getAcceptableTokens()
int[]	getDefaultTokens()
int[]	getRequiredTokens()
void	setClassAnnotationNames(String regex) Sets regex which matches names of class annotations which require class to have public no-argument ctor.
void	setCtorAnnotationNames(String regex) Sets regex which matches names of ctor annotations which make empty public ctor essential.
void	visitToken(com.puppycrawl.tools.checkstyle.api.DetailAST node)

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

clearMessages, destroy, finishTree, getFileContents, getLine, getLines, getMessages, getTabWidth, getTokenNames, init, isCommentNodesRequired, leaveToken, log, log, log, setFileContents, setTabWidth, setTokens

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

finishLocalSetup, getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, setId, setSeverity

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

configure, contextualize, getConfiguration, setupChild

Methods inherited from class java.lang.Object

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

Field Detail

MSG_KEY

public static final String MSG_KEY

Violation message key.

See Also:

Constant Field Values

Constructor Detail

EmptyPublicCtorInClassCheck

public EmptyPublicCtorInClassCheck()

Method Detail

setClassAnnotationNames

public void setClassAnnotationNames(String regex)

Sets regex which matches names of class annotations which require class to have public no-argument ctor.

Parameters:

regex - regex to match annotation names.

setCtorAnnotationNames

public void setCtorAnnotationNames(String regex)

Sets regex which matches names of ctor annotations which make empty public ctor essential.

Parameters:

regex - regex to match annotation names.

getDefaultTokens

public int[] getDefaultTokens()

Specified by:

getDefaultTokens in class com.puppycrawl.tools.checkstyle.api.AbstractCheck

getAcceptableTokens

public int[] getAcceptableTokens()

Specified by:

getAcceptableTokens in class com.puppycrawl.tools.checkstyle.api.AbstractCheck

getRequiredTokens

public int[] getRequiredTokens()

Specified by:

getRequiredTokens in class com.puppycrawl.tools.checkstyle.api.AbstractCheck

beginTree

public void beginTree(com.puppycrawl.tools.checkstyle.api.DetailAST aRootNode)

Overrides:

beginTree in class com.puppycrawl.tools.checkstyle.api.AbstractCheck

visitToken

public void visitToken(com.puppycrawl.tools.checkstyle.api.DetailAST node)

Overrides:

visitToken in class com.puppycrawl.tools.checkstyle.api.AbstractCheck