com.puppycrawl.tools.checkstyle.checks.coding

Class IllegalCatchCheck

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.coding.IllegalCatchCheck

All Implemented Interfaces:

Configurable, Contextualizable

public final class IllegalCatchCheck
extends AbstractCheck

Checks that certain exception types do not appear in a catch statement.

Rationale: catching java.lang.Exception, java.lang.Error or java.lang.RuntimeException is almost never acceptable. Novice developers often simply catch Exception in an attempt to handle multiple exception classes. This unfortunately leads to code that inadvertently catches NullPointerException, OutOfMemoryError, etc.

• Property illegalClassNames - Specify exception class names to reject. Type is java.lang.String[]. Default value is Error, Exception, RuntimeException, Throwable, java.lang.Error, java.lang.Exception, java.lang.RuntimeException, java.lang.Throwable.

To configure the check:

 <module name="IllegalCatch"/>
 

Example:

 try {
     // some code here
 } catch (Exception e) { // violation

 }

 try {
     // some code here
 } catch (ArithmeticException e) { // OK

 } catch (Exception e) { // violation, catching Exception is illegal
                           and order of catch blocks doesn't matter
 }

 try {
     // some code here
 } catch (ArithmeticException | Exception e) { // violation, catching Exception is illegal

 }

 try {
     // some code here
 } catch (ArithmeticException e) { // OK

 }

 

To configure the check to override the default list with ArithmeticException and OutOfMemoryError:

 <module name="IllegalCatch">
   <property name="illegalClassNames" value="ArithmeticException,
               OutOfMemoryError"/>
 </module>
 

Example:

 try {
     // some code here
 } catch (OutOfMemoryError e) { // violation

 }

 try {
     // some code here
 } catch (ArithmeticException e) { // violation

 }

 try {
     // some code here
 } catch (NullPointerException e) { // OK

 } catch (OutOfMemoryError e) { // violation

 }

 try {
     // some code here
 } catch (ArithmeticException | Exception e) {  // violation

 }

 try {
     // some code here
 } catch (Exception e) { // OK

 }
 

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

• illegal.catch

Since:

3.2

Nested Class Summary

Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean

AutomaticBean.OutputStreamOptions

Field Summary

Fields

Modifier and Type	Field and Description
static String	MSG_KEY A key is pointing to the warning message text in "messages.properties" file.

Constructor Summary

Constructors

Constructor and Description
IllegalCatchCheck()

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.
void	setIllegalClassNames(String... classNames) Setter to specify exception class names to reject.
void	visitToken(DetailAST detailAST) 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, isCommentNodesRequired, 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

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 String MSG_KEY

A key is pointing to the warning message text in "messages.properties" file.

See Also:

Constant Field Values

Constructor Detail

IllegalCatchCheck

public IllegalCatchCheck()

Method Detail

setIllegalClassNames

public void setIllegalClassNames(String... classNames)

Setter to specify exception class names to reject.

Parameters:

classNames - array of illegal exception classes

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 detailAST)

Description copied from class: AbstractCheck

Called to process a token.

Overrides:

visitToken in class AbstractCheck

Parameters:

detailAST - the token to process