Class RequireThisCheck
- java.lang.Object
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- com.puppycrawl.tools.checkstyle.api.AutomaticBean
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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.RequireThisCheck
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- All Implemented Interfaces:
Configurable
,Contextualizable
public class RequireThisCheck extends AbstractCheck
Checks that code doesn't rely on the "this" default. That is references to instance variables and methods of the present object are explicitly of the form "this.varName" or "this.methodName(args)".
Check has the following options:checkFields - whether to check references to fields. Default value is true.
checkMethods - whether to check references to methods. Default value is true.
validateOnlyOverlapping - whether to check only overlapping by variables or arguments. Default value is true.
Warning: the Check is very controversial if 'validateOnlyOverlapping' option is set to 'false' and not that actual nowadays.
Examples of use:
<module name="RequireThis"/>
An example of how to configure to checkthis
qualifier for methods only:<module name="RequireThis"> <property name="checkFields" value="false"/> <property name="checkMethods" value="true"/> </module>
Rationale:
- The same notation/habit for C++ and Java (C++ have global methods, so having "this." do make sense in it to distinguish call of method of class instead of global).
- Non-IDE development (ease of refactoring, some clearness to distinguish static and non-static methods).
Limitations: Nothing is currently done about static variables or catch-blocks. Static methods invoked on a class name seem to be OK; both the class name and the method name have a DOT parent. Non-static methods invoked on either this or a variable name seem to be OK, likewise.
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Nested Class Summary
Nested Classes Modifier and Type Class Description private static class
RequireThisCheck.AbstractFrame
A declaration frame.private static class
RequireThisCheck.AnonymousClassFrame
An anonymous class frame; holds instance variable names.private static class
RequireThisCheck.BlockFrame
A frame initiated on entering a statement list; holds local variable names.private static class
RequireThisCheck.ClassFrame
A frame initiated at class, enum or interface definition; holds instance variable names.private static class
RequireThisCheck.ConstructorFrame
A frame initiated at constructor definition.private static class
RequireThisCheck.FrameType
An AbstractFrame type.private static class
RequireThisCheck.MethodFrame
A frame initiated at method definition; holds a method definition token.
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Field Summary
Fields Modifier and Type Field Description private static java.util.Set<java.lang.Integer>
ASSIGN_TOKENS
Set of all assign tokens.private boolean
checkFields
Whether we should check fields usage.private boolean
checkMethods
Whether we should check methods usage.private static java.util.Set<java.lang.Integer>
COMPOUND_ASSIGN_TOKENS
Set of all compound assign tokens.private RequireThisCheck.AbstractFrame
current
Frame for the currently processed AST.private static java.util.Set<java.lang.Integer>
DECLARATION_TOKENS
Set of all declaration tokens.private java.util.Map<DetailAST,RequireThisCheck.AbstractFrame>
frames
Tree of all the parsed frames.static java.lang.String
MSG_METHOD
A key is pointing to the warning message text in "messages.properties" file.static java.lang.String
MSG_VARIABLE
A key is pointing to the warning message text in "messages.properties" file.private boolean
validateOnlyOverlapping
Whether we should check only overlapping by variables or arguments.
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Constructor Summary
Constructors Constructor Description RequireThisCheck()
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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 boolean
canAssignValueToClassField(DetailAST ast)
Checks whether a value can be assigned to a field.private boolean
canBeReferencedFromStaticContext(DetailAST ident)
Checks whether a field can be referenced from a static context.private static void
collectDeclarations(java.util.Deque<RequireThisCheck.AbstractFrame> frameStack, DetailAST ast)
Parses the next AST for declarations.private static void
collectVariableDeclarations(DetailAST ast, RequireThisCheck.AbstractFrame frame)
Collects variable declarations.private void
endCollectingDeclarations(java.util.Queue<RequireThisCheck.AbstractFrame> frameStack, DetailAST ast)
Ends parsing of the AST for declarations.private RequireThisCheck.AbstractFrame
findClassFrame(DetailAST name, boolean lookForMethod)
Find the class frame containing declaration.private RequireThisCheck.AbstractFrame
findFrame(DetailAST name, boolean lookForMethod)
Find frame containing declaration.private static RequireThisCheck.AbstractFrame
findFrame(RequireThisCheck.AbstractFrame frame, DetailAST name, boolean lookForMethod)
Find frame containing declaration.int[]
getAcceptableTokens()
The configurable token set.private static java.util.Set<DetailAST>
getAllTokensOfType(DetailAST ast, int tokenType)
Collects all tokens of specific type starting with the current ast node.private static java.util.Set<DetailAST>
getAllTokensOfType(DetailAST ast, int tokenType, int endLineNumber)
Collects all tokens of specific type starting with the current ast node and which line number is lower or equal to the end line number.private static java.util.Set<DetailAST>
getAllTokensWhichAreEqualToCurrent(DetailAST ast, DetailAST token, int endLineNumber)
Collects all tokens which are equal to current token starting with the current ast node and which line number is lower or equal to the end line number.private static DetailAST
getBlockEndToken(DetailAST blockNameIdent, DetailAST blockStartToken)
Returns the token which ends the code block.private RequireThisCheck.AbstractFrame
getClassFrameWhereViolationIsFound(DetailAST ast)
Returns the class frame where violation is found (where the field is used without 'this') or null otherwise.private static DetailAST
getCodeBlockDefinitionToken(DetailAST ident)
Returns code block definition token for current identifier.int[]
getDefaultTokens()
Returns the default token a check is interested in.private RequireThisCheck.AbstractFrame
getFieldWithoutThis(DetailAST ast, int parentType)
Returns the frame where the field is declared, if the given field is used without 'this', and null otherwise.private RequireThisCheck.AbstractFrame
getMethodWithoutThis(DetailAST ast)
Returns the frame where the method is declared, if the given method is used without 'this' and null otherwise.private java.lang.String
getNearestClassFrameName()
Gets the name of the nearest parent ClassFrame.int[]
getRequiredTokens()
The tokens that this check must be registered for.private static boolean
isAnonymousClassDef(DetailAST ast)
Whether the AST is a definition of an anonymous class.private static boolean
isAssignToken(int tokenType)
Check that token is related to assign tokens.private static boolean
isCompoundAssignToken(int tokenType)
Check that token is related to compound assign tokens.private static boolean
isDeclarationToken(int parentType)
Check that token is related to Definition tokens.private static boolean
isInsideConstructorFrame(RequireThisCheck.AbstractFrame frame)
Checks whether a field usage frame is inside constructor frame.private static boolean
isLambdaParameter(DetailAST ast)
Checks if the token is a Lambda parameter.private boolean
isOverlappingByArgument(DetailAST ast)
Checks whether an overlapping by method or constructor argument takes place.private boolean
isOverlappingByLocalVariable(DetailAST ast)
Checks whether an overlapping by local variable takes place.private static boolean
isReturnedVariable(RequireThisCheck.AbstractFrame currentFrame, DetailAST ident)
Checks whether the current variable is returned from the method.private static boolean
isUserDefinedArrangementOfThis(RequireThisCheck.AbstractFrame currentFrame, DetailAST ident)
Checks whether user arranges 'this' for variable in method, constructor, or block on his own.private void
logViolation(java.lang.String msgKey, DetailAST ast, RequireThisCheck.AbstractFrame frame)
Helper method to log a LocalizedMessage.private void
processIdent(DetailAST ast)
Checks if a given IDENT is method call or field name which requires explicitthis
qualifier.void
setCheckFields(boolean checkFields)
Setter for checkFields property.void
setCheckMethods(boolean checkMethods)
Setter for checkMethods property.void
setValidateOnlyOverlapping(boolean validateOnlyOverlapping)
Setter for validateOnlyOverlapping property.void
visitToken(DetailAST ast)
Called to process a token.-
Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
destroy, finishTree, getClassLoader, getFileContents, getLine, getLines, getTabWidth, getTokenNames, init, isCommentNodesRequired, leaveToken, log, log, setClassLoader, setFileContents, setMessages, setTabWidth, setTokens
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Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, log, setId, setSeverity
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Methods inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean
configure, contextualize, finishLocalSetup, getConfiguration, setupChild
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Field Detail
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MSG_METHOD
public static final java.lang.String MSG_METHOD
A key is pointing to the warning message text in "messages.properties" file.- See Also:
- Constant Field Values
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MSG_VARIABLE
public static final java.lang.String MSG_VARIABLE
A key is pointing to the warning message text in "messages.properties" file.- See Also:
- Constant Field Values
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DECLARATION_TOKENS
private static final java.util.Set<java.lang.Integer> DECLARATION_TOKENS
Set of all declaration tokens.
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ASSIGN_TOKENS
private static final java.util.Set<java.lang.Integer> ASSIGN_TOKENS
Set of all assign tokens.
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COMPOUND_ASSIGN_TOKENS
private static final java.util.Set<java.lang.Integer> COMPOUND_ASSIGN_TOKENS
Set of all compound assign tokens.
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frames
private java.util.Map<DetailAST,RequireThisCheck.AbstractFrame> frames
Tree of all the parsed frames.
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current
private RequireThisCheck.AbstractFrame current
Frame for the currently processed AST.
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checkFields
private boolean checkFields
Whether we should check fields usage.
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checkMethods
private boolean checkMethods
Whether we should check methods usage.
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validateOnlyOverlapping
private boolean validateOnlyOverlapping
Whether we should check only overlapping by variables or arguments.
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Method Detail
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setCheckFields
public void setCheckFields(boolean checkFields)
Setter for checkFields property.- Parameters:
checkFields
- should we check fields usage or not.
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setCheckMethods
public void setCheckMethods(boolean checkMethods)
Setter for checkMethods property.- Parameters:
checkMethods
- should we check methods usage or not.
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setValidateOnlyOverlapping
public void setValidateOnlyOverlapping(boolean validateOnlyOverlapping)
Setter for validateOnlyOverlapping property.- Parameters:
validateOnlyOverlapping
- should we check only overlapping by variables or arguments.
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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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processIdent
private void processIdent(DetailAST ast)
Checks if a given IDENT is method call or field name which requires explicitthis
qualifier.- Parameters:
ast
- IDENT to check.
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logViolation
private void logViolation(java.lang.String msgKey, DetailAST ast, RequireThisCheck.AbstractFrame frame)
Helper method to log a LocalizedMessage.- Parameters:
ast
- a node to get line id column numbers associated with the message.msgKey
- key to locale message format.frame
- the class frame where the violation is found.
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getFieldWithoutThis
private RequireThisCheck.AbstractFrame getFieldWithoutThis(DetailAST ast, int parentType)
Returns the frame where the field is declared, if the given field is used without 'this', and null otherwise.- Parameters:
ast
- field definition ast token.parentType
- type of the parent.- Returns:
- the frame where the field is declared, if the given field is used without 'this' and null otherwise.
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collectDeclarations
private static void collectDeclarations(java.util.Deque<RequireThisCheck.AbstractFrame> frameStack, DetailAST ast)
Parses the next AST for declarations.- Parameters:
frameStack
- stack containing the FrameTree being built.ast
- AST to parse.
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collectVariableDeclarations
private static void collectVariableDeclarations(DetailAST ast, RequireThisCheck.AbstractFrame frame)
Collects variable declarations.- Parameters:
ast
- variable token.frame
- current frame.
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endCollectingDeclarations
private void endCollectingDeclarations(java.util.Queue<RequireThisCheck.AbstractFrame> frameStack, DetailAST ast)
Ends parsing of the AST for declarations.- Parameters:
frameStack
- Stack containing the FrameTree being built.ast
- AST that was parsed.
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isAnonymousClassDef
private static boolean isAnonymousClassDef(DetailAST ast)
Whether the AST is a definition of an anonymous class.- Parameters:
ast
- the AST to process.- Returns:
- true if the AST is a definition of an anonymous class.
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getClassFrameWhereViolationIsFound
private RequireThisCheck.AbstractFrame getClassFrameWhereViolationIsFound(DetailAST ast)
Returns the class frame where violation is found (where the field is used without 'this') or null otherwise.- Parameters:
ast
- IDENT ast to check.- Returns:
- the class frame where violation is found or null otherwise.
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isUserDefinedArrangementOfThis
private static boolean isUserDefinedArrangementOfThis(RequireThisCheck.AbstractFrame currentFrame, DetailAST ident)
Checks whether user arranges 'this' for variable in method, constructor, or block on his own.- Parameters:
currentFrame
- current frame.ident
- ident token.- Returns:
- true if user arranges 'this' for variable in method, constructor, or block on his own.
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getBlockEndToken
private static DetailAST getBlockEndToken(DetailAST blockNameIdent, DetailAST blockStartToken)
Returns the token which ends the code block.- Parameters:
blockNameIdent
- block name identifier.blockStartToken
- token which starts the block.- Returns:
- the token which ends the code block.
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isReturnedVariable
private static boolean isReturnedVariable(RequireThisCheck.AbstractFrame currentFrame, DetailAST ident)
Checks whether the current variable is returned from the method.- Parameters:
currentFrame
- current frame.ident
- variable ident token.- Returns:
- true if the current variable is returned from the method.
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canBeReferencedFromStaticContext
private boolean canBeReferencedFromStaticContext(DetailAST ident)
Checks whether a field can be referenced from a static context.- Parameters:
ident
- ident token.- Returns:
- true if field can be referenced from a static context.
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getCodeBlockDefinitionToken
private static DetailAST getCodeBlockDefinitionToken(DetailAST ident)
Returns code block definition token for current identifier.- Parameters:
ident
- ident token.- Returns:
- code block definition token for current identifier or null if code block definition was not found.
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canAssignValueToClassField
private boolean canAssignValueToClassField(DetailAST ast)
Checks whether a value can be assigned to a field. A value can be assigned to a final field only in constructor block. If there is a method block, value assignment can be performed only to non final field.- Parameters:
ast
- an identifier token.- Returns:
- true if a value can be assigned to a field.
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isInsideConstructorFrame
private static boolean isInsideConstructorFrame(RequireThisCheck.AbstractFrame frame)
Checks whether a field usage frame is inside constructor frame.- Parameters:
frame
- frame, where field is used.- Returns:
- true if the field usage frame is inside constructor frame.
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isOverlappingByArgument
private boolean isOverlappingByArgument(DetailAST ast)
Checks whether an overlapping by method or constructor argument takes place.- Parameters:
ast
- an identifier.- Returns:
- true if an overlapping by method or constructor argument takes place.
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isOverlappingByLocalVariable
private boolean isOverlappingByLocalVariable(DetailAST ast)
Checks whether an overlapping by local variable takes place.- Parameters:
ast
- an identifier.- Returns:
- true if an overlapping by local variable takes place.
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getAllTokensOfType
private static java.util.Set<DetailAST> getAllTokensOfType(DetailAST ast, int tokenType)
Collects all tokens of specific type starting with the current ast node.- Parameters:
ast
- ast node.tokenType
- token type.- Returns:
- a set of all tokens of specific type starting with the current ast node.
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getAllTokensOfType
private static java.util.Set<DetailAST> getAllTokensOfType(DetailAST ast, int tokenType, int endLineNumber)
Collects all tokens of specific type starting with the current ast node and which line number is lower or equal to the end line number.- Parameters:
ast
- ast node.tokenType
- token type.endLineNumber
- end line number.- Returns:
- a set of all tokens of specific type starting with the current ast node and which line number is lower or equal to the end line number.
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getAllTokensWhichAreEqualToCurrent
private static java.util.Set<DetailAST> getAllTokensWhichAreEqualToCurrent(DetailAST ast, DetailAST token, int endLineNumber)
Collects all tokens which are equal to current token starting with the current ast node and which line number is lower or equal to the end line number.- Parameters:
ast
- ast node.token
- token.endLineNumber
- end line number.- Returns:
- a set of tokens which are equal to current token starting with the current ast node and which line number is lower or equal to the end line number.
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getMethodWithoutThis
private RequireThisCheck.AbstractFrame getMethodWithoutThis(DetailAST ast)
Returns the frame where the method is declared, if the given method is used without 'this' and null otherwise.- Parameters:
ast
- the IDENT ast of the name to check.- Returns:
- the frame where the method is declared, if the given method is used without 'this' and null otherwise.
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findClassFrame
private RequireThisCheck.AbstractFrame findClassFrame(DetailAST name, boolean lookForMethod)
Find the class frame containing declaration.- Parameters:
name
- IDENT ast of the declaration to find.lookForMethod
- whether we are looking for a method name.- Returns:
- AbstractFrame containing declaration or null.
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findFrame
private RequireThisCheck.AbstractFrame findFrame(DetailAST name, boolean lookForMethod)
Find frame containing declaration.- Parameters:
name
- IDENT ast of the declaration to find.lookForMethod
- whether we are looking for a method name.- Returns:
- AbstractFrame containing declaration or null.
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findFrame
private static RequireThisCheck.AbstractFrame findFrame(RequireThisCheck.AbstractFrame frame, DetailAST name, boolean lookForMethod)
Find frame containing declaration.- Parameters:
frame
- The parent frame to searching in.name
- IDENT ast of the declaration to find.lookForMethod
- whether we are looking for a method name.- Returns:
- AbstractFrame containing declaration or null.
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isDeclarationToken
private static boolean isDeclarationToken(int parentType)
Check that token is related to Definition tokens.- Parameters:
parentType
- token Type.- Returns:
- true if token is related to Definition Tokens.
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isAssignToken
private static boolean isAssignToken(int tokenType)
Check that token is related to assign tokens.- Parameters:
tokenType
- token type.- Returns:
- true if token is related to assign tokens.
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isCompoundAssignToken
private static boolean isCompoundAssignToken(int tokenType)
Check that token is related to compound assign tokens.- Parameters:
tokenType
- token type.- Returns:
- true if token is related to compound assign tokens.
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getNearestClassFrameName
private java.lang.String getNearestClassFrameName()
Gets the name of the nearest parent ClassFrame.- Returns:
- the name of the nearest parent ClassFrame.
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isLambdaParameter
private static boolean isLambdaParameter(DetailAST ast)
Checks if the token is a Lambda parameter.- Parameters:
ast
- theDetailAST
value of the token to be checked- Returns:
- true if the token is a Lambda parameter
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