com.puppycrawl.tools.checkstyle.checks.coding

Class IllegalInstantiationCheck

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.coding.IllegalInstantiationCheck

All Implemented Interfaces:

Configurable, Contextualizable

public class IllegalInstantiationCheck
extends Check

Checks for illegal instantiations where a factory method is preferred.

Rationale: Depending on the project, for some classes it might be preferable to create instances through factory methods rather than calling the constructor.

A simple example is the java.lang.Boolean class, to save memory and CPU cycles it is preferable to use the predeifined constants TRUE and FALSE. Constructor invocations should be replaced by calls to Boolean.valueOf().

Some extremely performance sensitive projects may require the use of factory methods for other classes as well, to enforce the usage of number caches or object pools.

Limitations: It is currently not possible to specify array classes.

An example of how to configure the check is:

 <module name="IllegalInstantiation"/>
 

Author:

lkuehne

Constructor Summary

Constructors

Constructor and Description
IllegalInstantiationCheck()

Method Summary

Methods

Modifier and Type	Method and Description
void	beginTree(DetailAST aRootAST) Called before the starting to process a tree.
void	finishTree(DetailAST aRootAST) Called after finished processing a tree.
int[]	getAcceptableTokens() Prevent user from changing tokens in the configuration.
int[]	getDefaultTokens() Returns the default token a check is interested in.
int[]	getRequiredTokens() The tokens that this check must be registered for.
void	setClasses(String aClassNames) Sets the classes that are illegal to instantiate.
void	visitToken(DetailAST aAST) Called to process a token.

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

destroy, getClassLoader, getFileContents, getLines, getTabWidth, getTokenNames, init, leaveToken, log, log, setClassLoader, setFileContents, setMessages, setTabWidth, setTokens

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

getId, getMessageBundle, getSeverity, getSeverityLevel, log, log, log, log, log, log, log, log, log, setId, 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

IllegalInstantiationCheck

public IllegalInstantiationCheck()

Method Detail

getDefaultTokens

public int[] getDefaultTokens()

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:

TokenTypes

getAcceptableTokens

public int[] getAcceptableTokens()

Prevent user from changing tokens in the configuration.

Overrides:

getAcceptableTokens in class Check

Returns:

empty array to not allow user to change configuration.

See Also:

Check

getRequiredTokens

public int[] getRequiredTokens()

The tokens that this check must be registered for.

Overrides:

getRequiredTokens in class Check

Returns:

the token set this must be registered for.

See Also:

TokenTypes

beginTree

public void beginTree(DetailAST aRootAST)

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

Overrides:

beginTree in class Check

Parameters:

aRootAST - the root of the tree

visitToken

public void visitToken(DetailAST aAST)

Called to process a token.

Overrides:

visitToken in class Check

Parameters:

aAST - the token to process

finishTree

public void finishTree(DetailAST aRootAST)

Called after finished processing a tree. Ideal place to report on information collected whilst processing a tree.

Overrides:

finishTree in class Check

Parameters:

aRootAST - the root of the tree

setClasses

public void setClasses(String aClassNames)

Sets the classes that are illegal to instantiate.

Parameters:

aClassNames - a comma seperate list of class names