com.puppycrawl.tools.checkstyle.checks.design

Class MutableExceptionCheck

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.MutableExceptionCheck

All Implemented Interfaces:

Configurable, Contextualizable

public final class MutableExceptionCheck
extends AbstractCheck

Ensures that exceptions (classes with names conforming to some regular expression and explicitly extending classes with names conforming to other regular expression) are immutable. That is, they have only final fields.

Rationale: Exception instances should represent an error condition. Having non final fields not only allows the state to be modified by accident and therefore mask the original condition but also allows developers to accidentally forget to initialise state thereby leading to code catching the exception to draw incorrect conclusions based on the state.

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	checking Should we check current class or not.
private java.util.Deque<java.lang.Boolean>	checkingStack Stack of checking information for classes.
private static java.lang.String	DEFAULT_FORMAT Default value for format and extendedClassNameFormat properties.
private java.util.regex.Pattern	extendedClassNameFormat Pattern for class name that is being extended.
private java.util.regex.Pattern	format The regexp to match against.
static java.lang.String	MSG_KEY A key is pointing to the warning message text in "messages.properties" file.

Constructor Summary

Constructors

Constructor and Description
MutableExceptionCheck()

Method Summary

Modifier and Type	Method and Description
int[]	getAcceptableTokens() The configurable token set.
int[]	getDefaultTokens() Returns the default token a check is interested in.
int[]	getRequiredTokens() The tokens that this check must be registered for.
private boolean	isExtendedClassNamedAsException(DetailAST ast) Checks that if extended class name conforms to specified format.
private boolean	isNamedAsException(DetailAST ast) Checks that a class name conforms to specified format.
private void	leaveClassDef() Called when we leave class definition.
void	leaveToken(DetailAST ast) Called after all the child nodes have been process.
void	setExtendedClassNameFormat(java.util.regex.Pattern extendedClassNameFormat) Sets the format of extended class name to the specified regular expression.
void	setFormat(java.util.regex.Pattern pattern) Set the format for the specified regular expression.
private void	visitClassDef(DetailAST ast) Called when we start processing class definition.
void	visitToken(DetailAST ast) Called to process a token.
private void	visitVariableDef(DetailAST ast) Checks variable definition.

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

beginTree, destroy, finishTree, getClassLoader, getFileContents, getLine, getLines, getTabWidth, getTokenNames, init, isCommentNodesRequired, log, log, setClassLoader, setFileContents, setMessages, setTabWidth, setTokens

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

getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, 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

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

DEFAULT_FORMAT

private static final java.lang.String DEFAULT_FORMAT

Default value for format and extendedClassNameFormat properties.

See Also:

Constant Field Values

checkingStack

private final java.util.Deque<java.lang.Boolean> checkingStack

Stack of checking information for classes.

extendedClassNameFormat

private java.util.regex.Pattern extendedClassNameFormat

Pattern for class name that is being extended.

checking

private boolean checking

Should we check current class or not.

format

private java.util.regex.Pattern format

The regexp to match against.

Constructor Detail

MutableExceptionCheck

public MutableExceptionCheck()

Method Detail

setExtendedClassNameFormat

public void setExtendedClassNameFormat(java.util.regex.Pattern extendedClassNameFormat)

Sets the format of extended class name to the specified regular expression.

Parameters:

extendedClassNameFormat - a String value

setFormat

public void setFormat(java.util.regex.Pattern pattern)

Set the format for the specified regular expression.

Parameters:

pattern - the new pattern

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

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

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

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

visitClassDef

private void visitClassDef(DetailAST ast)

Called when we start processing class definition.

Parameters:

ast - class definition node

leaveClassDef

private void leaveClassDef()

Called when we leave class definition.

visitVariableDef

private void visitVariableDef(DetailAST ast)

Checks variable definition.

Parameters:

ast - variable def node for check

isNamedAsException

private boolean isNamedAsException(DetailAST ast)

Checks that a class name conforms to specified format.

Parameters:

ast - class definition node

Returns:

true if a class name conforms to specified format

isExtendedClassNamedAsException

private boolean isExtendedClassNamedAsException(DetailAST ast)

Checks that if extended class name conforms to specified format.

Parameters:

ast - class definition node

Returns:

true if extended class name conforms to specified format