Class BooleanExpressionComplexityCheck
- java.lang.Object
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- com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
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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.metrics.BooleanExpressionComplexityCheck
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- All Implemented Interfaces:
Configurable
,Contextualizable
public final class BooleanExpressionComplexityCheck extends AbstractCheck
Restricts the number of boolean operators (&&
,||
,&
,|
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. Type isint
. Default value is3
. -
Property
tokens
- tokens to check Type isjava.lang.String[]
. Validation type istokenSet
. Default value is: LAND, BAND, LOR, BOR, BXOR.
Parent is
com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
-
booleanExpressionComplexity
- Since:
- 3.4
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Nested Class Summary
Nested Classes Modifier and Type Class Description private class
BooleanExpressionComplexityCheck.Context
Represents context (method/expression) in which we check complexity.-
Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
AbstractAutomaticBean.OutputStreamOptions
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Field Summary
Fields Modifier and Type Field Description private BooleanExpressionComplexityCheck.Context
context
Current context.private Deque<BooleanExpressionComplexityCheck.Context>
contextStack
Stack of contexts.private static int
DEFAULT_MAX
Default allowed complexity.private int
max
Specify the maximum number of boolean operations allowed in one expression.static String
MSG_KEY
A key is pointing to the warning message text in "messages.properties" file.
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Constructor Summary
Constructors Constructor Description BooleanExpressionComplexityCheck()
Creates new instance of the check.
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Method Summary
All Methods Static 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.private static boolean
isPassedInParameter(DetailAST logicalOperator)
Checks if logical operator is part of constructor or method call.private static boolean
isPipeOperator(DetailAST binaryOr)
Checks ifbinary OR
is applied to exceptions in multi-catch (pipe-syntax).private void
leaveExpr(DetailAST ast)
Restores previous context.private void
leaveMethodDef()
Removes old context.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.private void
visitExpr()
Creates and pushes new context.private void
visitMethodDef(DetailAST ast)
Creates new context for a given method.void
visitToken(DetailAST ast)
Called to process a token.-
Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
beginTree, clearViolations, destroy, finishTree, getFileContents, getFilePath, getLine, getLineCodePoints, getLines, getTabWidth, getTokenNames, getViolations, init, isCommentNodesRequired, log, log, log, 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.AbstractAutomaticBean
configure, contextualize, getConfiguration, setupChild
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Field Detail
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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
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DEFAULT_MAX
private static final int DEFAULT_MAX
Default allowed complexity.- See Also:
- Constant Field Values
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contextStack
private final Deque<BooleanExpressionComplexityCheck.Context> contextStack
Stack of contexts.
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max
private int max
Specify the maximum number of boolean operations allowed in one expression.
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context
private BooleanExpressionComplexityCheck.Context context
Current context.
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Constructor Detail
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BooleanExpressionComplexityCheck
public BooleanExpressionComplexityCheck()
Creates new instance of the check.
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Method Detail
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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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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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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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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.- Since:
- 3.4
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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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isPassedInParameter
private static boolean isPassedInParameter(DetailAST logicalOperator)
Checks if logical operator is part of constructor or method call.- Parameters:
logicalOperator
- logical operator- Returns:
- true if logical operator is part of constructor or method call
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isPipeOperator
private static boolean isPipeOperator(DetailAST binaryOr)
Checks ifbinary OR
is applied to exceptions in multi-catch (pipe-syntax).- Parameters:
binaryOr
-binary or
- Returns:
- true if binary or is applied to exceptions in multi-catch.
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leaveToken
public void leaveToken(DetailAST ast)
Description copied from class:AbstractCheck
Called after all the child nodes have been process.- Overrides:
leaveToken
in classAbstractCheck
- Parameters:
ast
- the token leaving
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visitMethodDef
private void visitMethodDef(DetailAST ast)
Creates new context for a given method.- Parameters:
ast
- a method we start to check.
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leaveMethodDef
private void leaveMethodDef()
Removes old context.
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visitExpr
private void visitExpr()
Creates and pushes new context.
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