Class MutableExceptionCheck
- java.lang.Object
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- com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
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- com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
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- com.puppycrawl.tools.checkstyle.api.AbstractCheck
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- com.puppycrawl.tools.checkstyle.checks.design.MutableExceptionCheck
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- All Implemented Interfaces:
Configurable
,Contextualizable
public final class MutableExceptionCheck extends AbstractCheck
Ensures that exception classes (classes with names conforming to some pattern and explicitly extending classes with names conforming to other pattern) are immutable, that is, that they have only final fields.The current algorithm is very simple: it checks that all members of exception are final. The user can still mutate an exception's instance (e.g. Throwable has a method called
setStackTrace
which changes the exception's stack trace). But, at least, all information provided by this exception type is unchangeable.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 set the initial state. In both cases, code catching the exception could draw incorrect conclusions based on the state.
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Property
extendedClassNameFormat
- Specify pattern for extended class names. Type isjava.util.regex.Pattern
. Default value is"^.*Exception$|^.*Error$|^.*Throwable$"
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Property
format
- Specify pattern for exception class names. Type isjava.util.regex.Pattern
. Default value is"^.*Exception$|^.*Error$|^.*Throwable$"
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Parent is
com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
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mutable.exception
- Since:
- 3.2
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Nested Class Summary
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Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
AbstractAutomaticBean.OutputStreamOptions
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Field Summary
Fields Modifier and Type Field Description private boolean
checking
Should we check current class or not.private Deque<Boolean>
checkingStack
Stack of checking information for classes.private static String
DEFAULT_FORMAT
Default value for format and extendedClassNameFormat properties.private Pattern
extendedClassNameFormat
Specify pattern for extended class names.private Pattern
format
Specify pattern for exception class names.static String
MSG_KEY
A key is pointing to the warning message text in "messages.properties" file.
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Constructor Summary
Constructors Constructor Description MutableExceptionCheck()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method 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(Pattern extendedClassNameFormat)
Setter to specify pattern for extended class names.void
setFormat(Pattern pattern)
Setter to specify pattern for exception class names.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, clearViolations, destroy, finishTree, getFileContents, getFilePath, getLine, getLineCodePoints, getLines, getTabWidth, getTokenNames, getViolations, init, isCommentNodesRequired, log, log, log, setFileContents, setTabWidth, setTokens
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Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
finishLocalSetup, getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, setId, setSeverity
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Methods inherited from class com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
configure, contextualize, getConfiguration, setupChild
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Field Detail
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MSG_KEY
public static final String MSG_KEY
A key is pointing to the warning message text in "messages.properties" file.- See Also:
- Constant Field Values
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DEFAULT_FORMAT
private static final String DEFAULT_FORMAT
Default value for format and extendedClassNameFormat properties.- See Also:
- Constant Field Values
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checkingStack
private final Deque<Boolean> checkingStack
Stack of checking information for classes.
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extendedClassNameFormat
private Pattern extendedClassNameFormat
Specify pattern for extended class names.
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checking
private boolean checking
Should we check current class or not.
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Constructor Detail
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MutableExceptionCheck
public MutableExceptionCheck()
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Method Detail
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setExtendedClassNameFormat
public void setExtendedClassNameFormat(Pattern extendedClassNameFormat)
Setter to specify pattern for extended class names.- Parameters:
extendedClassNameFormat
- aString
value- Since:
- 6.2
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setFormat
public void setFormat(Pattern pattern)
Setter to specify pattern for exception class names.- Parameters:
pattern
- the new pattern- Since:
- 3.2
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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 classAbstractCheck
- Returns:
- the default tokens
- See Also:
TokenTypes
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getRequiredTokens
public int[] getRequiredTokens()
Description copied from class:AbstractCheck
The tokens that this check must be registered for.- Specified by:
getRequiredTokens
in classAbstractCheck
- Returns:
- the token set this must be registered for.
- See Also:
TokenTypes
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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 classAbstractCheck
- Returns:
- the token set this check is designed for.
- See Also:
TokenTypes
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visitToken
public void visitToken(DetailAST ast)
Description copied from class:AbstractCheck
Called to process a token.- Overrides:
visitToken
in classAbstractCheck
- Parameters:
ast
- the token to process
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leaveToken
public void leaveToken(DetailAST ast)
Description copied from class:AbstractCheck
Called after all the child nodes have been process.- Overrides:
leaveToken
in classAbstractCheck
- Parameters:
ast
- the token leaving
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visitClassDef
private void visitClassDef(DetailAST ast)
Called when we start processing class definition.- Parameters:
ast
- class definition node
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leaveClassDef
private void leaveClassDef()
Called when we leave class definition.
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visitVariableDef
private void visitVariableDef(DetailAST ast)
Checks variable definition.- Parameters:
ast
- variable def node for check
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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
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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
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