Class ModifiedControlVariableCheck
- 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.coding.ModifiedControlVariableCheck
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- All Implemented Interfaces:
Configurable
,Contextualizable
public final class ModifiedControlVariableCheck extends AbstractCheck
Checks that for loop control variables are not modified inside the for block. An example is:for (int i = 0; i < 1; i++) { i++; // violation }
Rationale: If the control variable is modified inside the loop body, the program flow becomes more difficult to follow. See FOR statement specification for more details.
Such loop would be suppressed:
for (int i = 0; i < 10;) { i++; }
NOTE:The check works with only primitive type variables. The check will not work for arrays used as control variable.An example is
for (int a[]={0};a[0] < 10;a[0]++) { a[0]++; // it will skip this violation }
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Property
skipEnhancedForLoopVariable
- Control whether to check enhanced for-loop variable. Type isboolean
. Default value isfalse
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Parent is
com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
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modified.control.variable
- Since:
- 3.5
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Nested Class Summary
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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 static String
ILLEGAL_TYPE_OF_TOKEN
Message thrown with IllegalStateException.static String
MSG_KEY
A key is pointing to the warning message text in "messages.properties" file.private static BitSet
MUTATION_OPERATIONS
Operations which can change control variable in update part of the loop.private boolean
skipEnhancedForLoopVariable
Control whether to check enhanced for-loop variable.private Deque<Deque<String>>
variableStack
Stack of block parameters.
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Constructor Summary
Constructors Constructor Description ModifiedControlVariableCheck()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
beginTree(DetailAST rootAST)
Called before the starting to process a tree.private void
checkIdent(DetailAST ast)
Check if ident is parameter.private void
enterBlock()
Enters an inner class, which requires a new variable set.private void
exitBlock()
Leave an inner class, so restore variable set.private static List<DetailAST>
findChildrenOfExpressionType(DetailAST ast)
Find all child of given AST of type TokenType.EXPR.int[]
getAcceptableTokens()
The configurable token set.private Deque<String>
getCurrentVariables()
Get current variable stack.int[]
getDefaultTokens()
Returns the default token a check is interested in.private static Set<String>
getForInitVariables(DetailAST ast)
Get all variables initialized In init part of for loop.private static Set<String>
getForIteratorVariables(DetailAST ast)
Get all variables which for loop iterating part change in every loop.int[]
getRequiredTokens()
The tokens that this check must be registered for.private static Set<String>
getVariablesManagedByForLoop(DetailAST ast)
Determines which variable are specific to for loop and should not be change by inner loop body.private void
leaveForDef(DetailAST ast)
Pops the variables from the stack.private void
leaveForEach(DetailAST paramDef)
Push current variables to the stack.private void
leaveForIter(DetailAST ast)
Push current variables to the stack.void
leaveToken(DetailAST ast)
Called after all the child nodes have been process.private void
popCurrentVariables(int count)
Pops given number of variables from currentVariables.void
setSkipEnhancedForLoopVariable(boolean skipEnhancedForLoopVariable)
Setter to control whether to check enhanced for-loop variable.void
visitToken(DetailAST ast)
Called to process a token.-
Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
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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ILLEGAL_TYPE_OF_TOKEN
private static final String ILLEGAL_TYPE_OF_TOKEN
Message thrown with IllegalStateException.- See Also:
- Constant Field Values
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MUTATION_OPERATIONS
private static final BitSet MUTATION_OPERATIONS
Operations which can change control variable in update part of the loop.
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variableStack
private final Deque<Deque<String>> variableStack
Stack of block parameters.
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skipEnhancedForLoopVariable
private boolean skipEnhancedForLoopVariable
Control whether to check enhanced for-loop variable.
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Constructor Detail
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ModifiedControlVariableCheck
public ModifiedControlVariableCheck()
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Method Detail
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setSkipEnhancedForLoopVariable
public void setSkipEnhancedForLoopVariable(boolean skipEnhancedForLoopVariable)
Setter to control whether to check enhanced for-loop variable.- Parameters:
skipEnhancedForLoopVariable
- whether to skip enhanced for-loop variable- Since:
- 6.8
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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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beginTree
public void beginTree(DetailAST rootAST)
Description copied from class:AbstractCheck
Called before the starting to process a tree. Ideal place to initialize information that is to be collected whilst processing a tree.- Overrides:
beginTree
in classAbstractCheck
- Parameters:
rootAST
- the root of the tree
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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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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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enterBlock
private void enterBlock()
Enters an inner class, which requires a new variable set.
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exitBlock
private void exitBlock()
Leave an inner class, so restore variable set.
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getCurrentVariables
private Deque<String> getCurrentVariables()
Get current variable stack.- Returns:
- current variable stack
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checkIdent
private void checkIdent(DetailAST ast)
Check if ident is parameter.- Parameters:
ast
- ident to check.
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leaveForIter
private void leaveForIter(DetailAST ast)
Push current variables to the stack.- Parameters:
ast
- a for definition.
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getVariablesManagedByForLoop
private static Set<String> getVariablesManagedByForLoop(DetailAST ast)
Determines which variable are specific to for loop and should not be change by inner loop body.- Parameters:
ast
- For Loop- Returns:
- Set of Variable Name which are managed by for
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leaveForEach
private void leaveForEach(DetailAST paramDef)
Push current variables to the stack.- Parameters:
paramDef
- a for-each clause variable
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leaveForDef
private void leaveForDef(DetailAST ast)
Pops the variables from the stack.- Parameters:
ast
- a for definition.
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popCurrentVariables
private void popCurrentVariables(int count)
Pops given number of variables from currentVariables.- Parameters:
count
- Count of variables to be popped from currentVariables
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getForInitVariables
private static Set<String> getForInitVariables(DetailAST ast)
Get all variables initialized In init part of for loop.- Parameters:
ast
- for loop token- Returns:
- set of variables initialized in for loop
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getForIteratorVariables
private static Set<String> getForIteratorVariables(DetailAST ast)
Get all variables which for loop iterating part change in every loop.- Parameters:
ast
- for loop literal(TokenTypes.LITERAL_FOR)- Returns:
- names of variables change in iterating part of for
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findChildrenOfExpressionType
private static List<DetailAST> findChildrenOfExpressionType(DetailAST ast)
Find all child of given AST of type TokenType.EXPR.- Parameters:
ast
- parent of expressions to find- Returns:
- all child of given ast
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