Class EmptyCatchBlockCheck
- 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.blocks.EmptyCatchBlockCheck
-
- 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) { }
-
-
Field Summary
Fields Modifier and Type Field Description private java.lang.String
commentFormat
Format of comment.private java.util.regex.Pattern
commentRegexp
Regular expression pattern compiled from comment's format.private java.lang.String
exceptionVariableName
Format of skipping exception's variable name.static java.lang.String
MSG_KEY_CATCH_BLOCK_EMPTY
A key is pointing to the warning message text in "messages.properties" file.private java.util.regex.Pattern
variableNameRegexp
Regular expression pattern compiled from exception's variable name.
-
Constructor Summary
Constructors Constructor Description EmptyCatchBlockCheck()
-
Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description int[]
getAcceptableTokens()
The configurable token set.private static java.lang.String
getCommentFirstLine(DetailAST catchAst)
Gets the first line of comment in catch block.int[]
getDefaultTokens()
Returns the default token a check is interested in.private static java.lang.String
getExceptionVariableName(DetailAST catchAst)
Gets variable's name associated with exception.int[]
getRequiredTokens()
The tokens that this check must be registered for.boolean
isCommentNodesRequired()
Whether comment nodes are required or not.private static boolean
isEmptyCatchBlock(DetailAST catchAst)
Checks if catch block is empty or contains only comments.private boolean
isVerifiable(DetailAST emptyCatchAst, java.lang.String commentContent)
Checks if current empty catch block is verifiable according to Check's options (exception's variable name and comment format are both in consideration).void
setCommentFormat(java.lang.String commentFormat)
Setter for comment format.void
setExceptionVariableName(java.lang.String exceptionVariableName)
Setter for exception's variable name format.private void
visitCatchBlock(DetailAST catchAst)
Visits catch ast node, if it is empty catch block - checks it according to Check's options.void
visitToken(DetailAST ast)
Called to process a token.-
Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
beginTree, destroy, finishTree, getClassLoader, getFileContents, getLine, getLines, getTabWidth, getTokenNames, init, leaveToken, 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
-
-
-
-
Field Detail
-
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
-
exceptionVariableName
private java.lang.String exceptionVariableName
Format of skipping exception's variable name.
-
commentFormat
private java.lang.String commentFormat
Format of comment.
-
variableNameRegexp
private java.util.regex.Pattern variableNameRegexp
Regular expression pattern compiled from exception's variable name.
-
commentRegexp
private java.util.regex.Pattern commentRegexp
Regular expression pattern compiled from comment's format.
-
-
Method Detail
-
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.
-
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.
-
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
-
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
-
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
-
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.
-
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
-
visitCatchBlock
private void visitCatchBlock(DetailAST catchAst)
Visits catch ast node, if it is empty catch block - checks it according to Check's options. If exception's variable name or comment inside block are matching specified regexp - skips from consideration, else - puts violation.- Parameters:
catchAst
-LITERAL_CATCH
-
getCommentFirstLine
private static java.lang.String getCommentFirstLine(DetailAST catchAst)
Gets the first line of comment in catch block. If comment is single-line - returns it fully, else if comment is multi-line - returns the first line.- Parameters:
catchAst
-LITERAL_CATCH
- Returns:
- the first line of comment in catch block, "" if no comment was found.
-
isVerifiable
private boolean isVerifiable(DetailAST emptyCatchAst, java.lang.String commentContent)
Checks if current empty catch block is verifiable according to Check's options (exception's variable name and comment format are both in consideration).- Parameters:
emptyCatchAst
- empty catchLITERAL_CATCH
block.commentContent
- text of comment.- Returns:
- true if empty catch block is verifiable by Check.
-
isEmptyCatchBlock
private static boolean isEmptyCatchBlock(DetailAST catchAst)
Checks if catch block is empty or contains only comments.- Parameters:
catchAst
-LITERAL_CATCH
- Returns:
- true if catch block is empty.
-
getExceptionVariableName
private static java.lang.String getExceptionVariableName(DetailAST catchAst)
Gets variable's name associated with exception.- Parameters:
catchAst
-LITERAL_CATCH
- Returns:
- Variable's name associated with exception.
-
-