Class EmptyCatchBlockCheck
- java.lang.Object
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- com.puppycrawl.tools.checkstyle.api.AutomaticBean
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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.blocks.EmptyCatchBlockCheck
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- All Implemented Interfaces:
Configurable
,Contextualizable
public class EmptyCatchBlockCheck extends AbstractCheck
Checks for empty catch blocks. There are two options to make validation more precise:
exceptionVariableName - the name of variable associated with exception, if Check meets variable name matching specified value - empty block is suppressed.
default value: "^$"commentFormat - the format of the first comment inside empty catch block, if Check meets comment inside empty catch block matching specified format - empty block is suppressed. If it is multi-line comment - only its first line is analyzed.
default value: ".*"
So, by default Check allows empty catch block with any comment inside.If both options are specified - they are applied by any of them is matching.
Examples:To configure the Check to suppress empty catch block if exception's variable name is expected or ignore:
<module name="EmptyCatchBlock"> <property name="exceptionVariableName" value="ignore|expected;/> </module>
Such empty blocks would be both suppressed:
try { throw new RuntimeException(); } catch (RuntimeException expected) { }
try { throw new RuntimeException(); } catch (RuntimeException ignore) { }
To configure the Check to suppress empty catch block if single-line comment inside is "//This is expected":
<module name="EmptyCatchBlock"> <property name="commentFormat" value="This is expected"/> </module>
Such empty block would be suppressed:
try { throw new RuntimeException(); } catch (RuntimeException ex) { //This is expected }
To configure the Check to suppress empty catch block if single-line comment inside is "//This is expected" or exception's variable name is "myException":
<module name="EmptyCatchBlock"> <property name="commentFormat" value="This is expected"/> <property name="exceptionVariableName" value="myException"/> </module>
Such empty blocks would be both suppressed:
try { throw new RuntimeException(); } catch (RuntimeException ex) { //This is expected }
try { throw new RuntimeException(); } catch (RuntimeException myException) { }
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Nested Class Summary
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Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean
AutomaticBean.OutputStreamOptions
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Field Summary
Fields Modifier and Type Field Description static java.lang.String
MSG_KEY_CATCH_BLOCK_EMPTY
A key is pointing to the warning message text in "messages.properties" file.
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Constructor Summary
Constructors Constructor Description EmptyCatchBlockCheck()
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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.boolean
isCommentNodesRequired()
Whether comment nodes are required or not.void
setCommentFormat(java.lang.String commentFormat)
Setter for comment format.void
setExceptionVariableName(java.lang.String exceptionVariableName)
Setter for exception's variable name format.void
visitToken(DetailAST ast)
Called to process a token.-
Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
beginTree, clearMessages, destroy, finishTree, getClassLoader, getFileContents, getLine, getLines, getMessages, getTabWidth, getTokenNames, init, leaveToken, log, log, log, setClassLoader, 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.api.AutomaticBean
configure, contextualize, getConfiguration, setupChild
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Field Detail
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MSG_KEY_CATCH_BLOCK_EMPTY
public static final java.lang.String MSG_KEY_CATCH_BLOCK_EMPTY
A key is pointing to the warning message text in "messages.properties" file.- See Also:
- Constant Field Values
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Method Detail
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setExceptionVariableName
public void setExceptionVariableName(java.lang.String exceptionVariableName)
Setter for exception's variable name format.- Parameters:
exceptionVariableName
- format of exception's variable name.- Throws:
org.apache.commons.beanutils.ConversionException
- if unable to create Pattern object.
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setCommentFormat
public void setCommentFormat(java.lang.String commentFormat)
Setter for comment format.- Parameters:
commentFormat
- format of comment.- Throws:
org.apache.commons.beanutils.ConversionException
- if unable to create Pattern object.
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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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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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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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isCommentNodesRequired
public boolean isCommentNodesRequired()
Description copied from class:AbstractCheck
Whether comment nodes are required or not.- Overrides:
isCommentNodesRequired
in classAbstractCheck
- Returns:
- false as a default value.
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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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