com.puppycrawl.tools.checkstyle.checks.metrics

Class BooleanExpressionComplexityCheck

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.metrics.BooleanExpressionComplexityCheck

All Implemented Interfaces:

Configurable, Contextualizable

public final class BooleanExpressionComplexityCheck
extends AbstractCheck

Restrict the number of &&, ||, &, | and ^ in an expression.

Rationale: Too many conditions leads to code that is difficult to read and hence debug and maintain.

Note that the operators & and | are not only integer bitwise operators, they are also the non-shortcut versions of the boolean operators && and ||.

Note that &, | and ^ are not checked if they are part of constructor or method call because they can be applied to non boolean variables and Checkstyle does not know types of methods from different classes.

• Property max - Specify the maximum number of boolean operations allowed in one expression. Default value is 3.
• Property tokens - tokens to check Default value is: LAND, BAND, LOR, BOR, BXOR.

To configure the check:

 <module name="BooleanExpressionComplexity"/>
 

To configure the check with 7 allowed operation in boolean expression:

 <module name="BooleanExpressionComplexity">
   <property name="max" value="7"/>
 </module>
 

To configure the check to ignore & and |:

 <module name="BooleanExpressionComplexity">
   <property name="tokens" value="BXOR,LAND,LOR"/>
 </module>
 

Since:

3.4

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 java.lang.String	MSG_KEY A key is pointing to the warning message text in "messages.properties" file.

Constructor Summary

Constructors

Constructor and Description
BooleanExpressionComplexityCheck() Creates new instance of the check.

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	leaveToken(DetailAST ast) Called after all the child nodes have been process.
void	setMax(int max) Setter to specify the maximum number of boolean operations allowed in one expression.
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, isCommentNodesRequired, 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 java.lang.String MSG_KEY

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

See Also:

Constant Field Values

Constructor Detail

BooleanExpressionComplexityCheck

public BooleanExpressionComplexityCheck()

Creates new instance of the check.

Method Detail

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

setMax

public void setMax(int max)

Setter to specify the maximum number of boolean operations allowed in one expression.

Parameters:

max - new maximum allowed complexity.

visitToken

public void visitToken(DetailAST ast)

Description copied from class: AbstractCheck

Called to process a token.

Overrides:

visitToken in class AbstractCheck

Parameters:

ast - the token to process

leaveToken

public void leaveToken(DetailAST ast)

Description copied from class: AbstractCheck

Called after all the child nodes have been process.

Overrides:

leaveToken in class AbstractCheck

Parameters:

ast - the token leaving