Class EmptyCatchBlockCheck
- All Implemented Interfaces:
Configurable
,Contextualizable
Checks for empty catch blocks. By default check allows empty catch block with any comment inside.
There are two options to make validation more precise: exceptionVariableName and commentFormat. If both options are specified - they are applied by any of them is matching.
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Property
exceptionVariableName
- Specify the RegExp for the name of the variable associated with exception. If check meets variable name matching specified value - empty block is suppressed. Type isjava.util.regex.Pattern
. Default value is"^$"
. -
Property
commentFormat
- Specify the RegExp for 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. Type isjava.util.regex.Pattern
. Default value is".*"
.
To configure the check to suppress empty catch block if exception's variable name is
expected
or ignore
or there's any comment inside:
<module name="EmptyCatchBlock"> <property name="exceptionVariableName" value="expected|ignore"/> </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" (any option is matching):
<module name="EmptyCatchBlock"> <property name="commentFormat" value="This is expected"/> <property name="exceptionVariableName" value="myException"/> </module>
Such empty blocks would be suppressed:
try { throw new RuntimeException(); } catch (RuntimeException e) { //This is expected } ... try { throw new RuntimeException(); } catch (RuntimeException e) { // This is expected } ... try { throw new RuntimeException(); } catch (RuntimeException e) { // This is expected // some another comment } ... try { throw new RuntimeException(); } catch (RuntimeException e) { /* This is expected */ } ... try { throw new RuntimeException(); } catch (RuntimeException e) { /* * * This is expected * some another comment */ } ... try { throw new RuntimeException(); } catch (RuntimeException myException) { }
Parent is com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
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catch.block.empty
- Since:
- 6.4
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Nested Class Summary
Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean
AutomaticBean.OutputStreamOptions
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final String
A key is pointing to the warning message text in "messages.properties" file. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionint[]
The configurable token set.int[]
Returns the default token a check is interested in.int[]
The tokens that this check must be registered for.boolean
Whether comment nodes are required or not.void
setCommentFormat
(Pattern commentPattern) Setter to specify the RegExp for the first comment inside empty catch block.void
setExceptionVariableName
(Pattern exceptionVariablePattern) Setter to specify the RegExp for the name of the variable associated with exception.void
visitToken
(DetailAST ast) Called to process a token.Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
beginTree, clearMessages, destroy, finishTree, getFileContents, getLine, getLines, getMessages, getTabWidth, getTokenNames, init, leaveToken, 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
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Field Details
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MSG_KEY_CATCH_BLOCK_EMPTY
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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Constructor Details
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EmptyCatchBlockCheck
public EmptyCatchBlockCheck()
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Method Details
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setExceptionVariableName
Setter to specify the RegExp for the name of the variable associated with exception. If check meets variable name matching specified value - empty block is suppressed.- Parameters:
exceptionVariablePattern
- pattern of exception's variable name.
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setCommentFormat
Setter to specify the RegExp for 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.- Parameters:
commentPattern
- pattern of comment.
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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:
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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:
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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:
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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
Description copied from class:AbstractCheck
Called to process a token.- Overrides:
visitToken
in classAbstractCheck
- Parameters:
ast
- the token to process
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