com.puppycrawl.tools.checkstyle.checks.design

Class FinalClassCheck

java.lang.Object

com.puppycrawl.tools.checkstyle.api.AutomaticBean

com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter

com.puppycrawl.tools.checkstyle.api.AbstractCheck

com.puppycrawl.tools.checkstyle.checks.design.FinalClassCheck

All Implemented Interfaces:

Configurable, Contextualizable

public class FinalClassCheck
extends AbstractCheck

Checks that a class which has only private constructors is declared as final. Doesn't check for classes nested in interfaces or annotations, as they are always final there.

To configure the check:

 <module name="FinalClass"/>
 

Example:

 final class MyClass {  // OK
   private MyClass() { }
 }

 class MyClass { // violation, class should be declared final
   private MyClass() { }
 }

 class MyClass { // OK, since it has a public constructor
   int field1;
   String field2;
   private MyClass(int value) {
     this.field1 = value;
     this.field2 = " ";
   }
   public MyClass(String value) {
     this.field2 = value;
     this.field1 = 0;
   }
 }

 interface CheckInterface
 {
   class MyClass { // OK, nested class in interface is always final
     private MyClass() {}
   }
 }

 public @interface Test {
   public boolean enabled()
   default true;
   class MyClass { // OK, class nested in an annotation is always final
     private MyClass() { }
   }
 }

 class TestAnonymousInnerClasses { // OK, class has an anonymous inner class.
     public static final TestAnonymousInnerClasses ONE = new TestAnonymousInnerClasses() {

     };

     private TestAnonymousInnerClasses() {
     }
 }
 

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

• final.class

Since:

3.1

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	FinalClassCheck.ClassDesc Maintains information about class' ctors.

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

AutomaticBean.OutputStreamOptions

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Deque<FinalClassCheck.ClassDesc>	classes Keeps ClassDesc objects for stack of declared classes.
static java.lang.String	MSG_KEY A key is pointing to the warning message text in "messages.properties" file.
private static java.lang.String	PACKAGE_SEPARATOR Character separate package names in qualified name of java class.
private java.lang.String	packageName Full qualified name of the package.

Constructor Summary

Constructors

Constructor and Description
FinalClassCheck()

Method Summary

Modifier and Type	Method and Description
void	beginTree(DetailAST rootAST) Called before the starting to process a tree.
private static boolean	doesNameInExtendMatchSuperClassName(java.lang.String superClassQualifiedName, java.lang.String superClassInExtendClause) Checks if given super class name in extend clause match super class qualified name.
private static boolean	doesNameOfClassMatchAnonymousInnerClassName(DetailAST ast, FinalClassCheck.ClassDesc classDesc) Check if class name matches with anonymous inner class name.
private static java.lang.String	extractQualifiedName(DetailAST ast) Get name of class (with qualified package if specified) in ast.
int[]	getAcceptableTokens() The configurable token set.
private static java.lang.String	getClassNameFromQualifiedName(java.lang.String qualifiedName) Get class name from qualified name.
int[]	getDefaultTokens() Returns the default token a check is interested in.
private java.lang.String	getQualifiedClassName(DetailAST classAst) Get qualified class name from given class Ast.
private static java.lang.String	getQualifiedClassName(java.lang.String packageName, java.lang.String outerClassQualifiedName, java.lang.String className) Calculate qualified class name(package + class name) laying inside given outer class.
int[]	getRequiredTokens() The tokens that this check must be registered for.
private static java.lang.String	getSuperClassName(DetailAST classAst) Get super class name of given class.
void	leaveToken(DetailAST ast) Called after all the child nodes have been process.
private void	registerNestedSubclassToOuterSuperClasses(DetailAST classAst) Register to outer super classes of given classAst that given classAst is extending them.
void	visitToken(DetailAST ast) Called to process a token.

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

clearViolations, destroy, finishTree, getFileContents, getLine, getLineCodePoints, getLines, getTabWidth, getTokenNames, getViolations, init, isCommentNodesRequired, 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 java.lang.String MSG_KEY

A key is pointing to the warning message text in "messages.properties" file.

See Also:

Constant Field Values

PACKAGE_SEPARATOR

private static final java.lang.String PACKAGE_SEPARATOR

Character separate package names in qualified name of java class.

See Also:

Constant Field Values

classes

private java.util.Deque<FinalClassCheck.ClassDesc> classes

Keeps ClassDesc objects for stack of declared classes.

packageName

private java.lang.String packageName

Full qualified name of the package.

Constructor Detail

FinalClassCheck

public FinalClassCheck()

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

beginTree

public void beginTree(DetailAST rootAST)

Description copied from class: AbstractCheck

Called before the starting to process a tree. Ideal place to initialize information that is to be collected whilst processing a tree.

Overrides:

beginTree in class AbstractCheck

Parameters:

rootAST - the root of the tree

visitToken

public void visitToken(DetailAST ast)

Description copied from class: AbstractCheck

Called to process a token.

Overrides:

visitToken in class AbstractCheck

Parameters:

ast - the token to process

leaveToken

public void leaveToken(DetailAST ast)

Description copied from class: AbstractCheck

Called after all the child nodes have been process.

Overrides:

leaveToken in class AbstractCheck

Parameters:

ast - the token leaving

extractQualifiedName

private static java.lang.String extractQualifiedName(DetailAST ast)

Get name of class (with qualified package if specified) in ast.

Parameters:

ast - ast to extract class name from

Returns:

qualified name

registerNestedSubclassToOuterSuperClasses

private void registerNestedSubclassToOuterSuperClasses(DetailAST classAst)

Register to outer super classes of given classAst that given classAst is extending them.

Parameters:

classAst - class which outer super classes will be informed about nesting subclass

doesNameOfClassMatchAnonymousInnerClassName

private static boolean doesNameOfClassMatchAnonymousInnerClassName(DetailAST ast,
                                                                   FinalClassCheck.ClassDesc classDesc)

Check if class name matches with anonymous inner class name.

Parameters:

ast - current ast.

classDesc - class to match.

Returns:

true if current class name matches anonymous inner class name.

getQualifiedClassName

private java.lang.String getQualifiedClassName(DetailAST classAst)

Get qualified class name from given class Ast.

Parameters:

classAst - class to get qualified class name

Returns:

qualified class name of a class

getQualifiedClassName

private static java.lang.String getQualifiedClassName(java.lang.String packageName,
                                                      java.lang.String outerClassQualifiedName,
                                                      java.lang.String className)

Calculate qualified class name(package + class name) laying inside given outer class.

Parameters:

packageName - package name, empty string on default package

outerClassQualifiedName - qualified name(package + class) of outer class, null if doesn't exist

className - class name

Returns:

qualified class name(package + class name)

getSuperClassName

private static java.lang.String getSuperClassName(DetailAST classAst)

Get super class name of given class.

Parameters:

classAst - class

Returns:

super class name or null if super class is not specified

doesNameInExtendMatchSuperClassName

private static boolean doesNameInExtendMatchSuperClassName(java.lang.String superClassQualifiedName,
                                                           java.lang.String superClassInExtendClause)

Checks if given super class name in extend clause match super class qualified name.

Parameters:

superClassQualifiedName - super class qualified name (with package)

superClassInExtendClause - name in extend clause

Returns:

true if given super class name in extend clause match super class qualified name, false otherwise

getClassNameFromQualifiedName

private static java.lang.String getClassNameFromQualifiedName(java.lang.String qualifiedName)

Get class name from qualified name.

Parameters:

qualifiedName - qualified class name

Returns:

class name