Package com.puppycrawl.tools.checkstyle.checks.coding

Class RequireThisCheck

java.lang.Object
com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
com.puppycrawl.tools.checkstyle.api.AbstractCheck
com.puppycrawl.tools.checkstyle.checks.coding.RequireThisCheck
All Implemented Interfaces:
Configurable, Contextualizable
public class RequireThisCheck extends AbstractCheck
Checks that references to instance variables and methods of the present object are explicitly of the form "this.varName" or "this.methodName(args)" and that those references don't rely on the default behavior when "this." is absent.

Warning: the Check is very controversial if 'validateOnlyOverlapping' option is set to 'false' and not that actual nowadays.

Rationale:

  1. 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).
  2. Non-IDE development (ease of refactoring, some clearness to distinguish static and non-static methods).

Notes: 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.

Since:
3.4

  • Field Details

  • Constructor Details

  • Method Details

    • setCheckFields

      public void setCheckFields(boolean checkFields)
      Setter to control whether to check references to fields.
      Parameters:
      checkFields - should we check fields usage or not
      Since:
      3.4

    • setCheckMethods

      public void setCheckMethods(boolean checkMethods)
      Setter to control whether to check references to methods.
      Parameters:
      checkMethods - should we check methods usage or not
      Since:
      3.4

    • setValidateOnlyOverlapping

      public void setValidateOnlyOverlapping(boolean validateOnlyOverlapping)
      Setter to control whether to check only overlapping by variables or arguments.
      Parameters:
      validateOnlyOverlapping - should we check only overlapping by variables or arguments
      Since:
      6.17

    • 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:

    • 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:

    • 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:

    • 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 class AbstractCheck
      Parameters:
      rootAST - the root of the tree

    • 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

    • processIdent

      private void processIdent(DetailAST ast)
      Checks if a given IDENT is method call or field name which requires explicit this qualifier.
      Parameters:
      ast - IDENT to check.

    • shouldSkipAnnotationContext

      private static boolean shouldSkipAnnotationContext(DetailAST ast)
      Determines whether the given IDENT should be skipped because it is in an annotation context. When validateOnlyOverlapping is true, all annotation contexts are skipped. When it is false, only annotation structural elements (member names, type names, and annotation field defaults) are skipped, while actual field reference values inside annotations are still processed.
      Parameters:
      ast - IDENT token
      Returns:
      true if the IDENT should be skipped

    • isInsideAnnotationFieldDef

      private static boolean isInsideAnnotationFieldDef(DetailAST ast)
      Checks whether the given IDENT is inside an annotation field definition (e.g., default values in @interface members).
      Parameters:
      ast - IDENT token
      Returns:
      true if IDENT is inside an annotation field definition

    • isAnnotationStructuralElement

      private static boolean isAnnotationStructuralElement(DetailAST ast)
      Checks if an IDENT is an annotation structural element — either an annotation type name (e.g., SuppressWarnings in @SuppressWarnings) or an annotation member name (e.g., value in value = "unused").
      Parameters:
      ast - IDENT token
      Returns:
      true if the IDENT is an annotation type name or member name

    • logViolation

      private void logViolation(String msgKey, DetailAST ast, RequireThisCheck.AbstractFrame frame)
      Helper method to log a Violation.
      Parameters:
      msgKey - key to locale message format.
      ast - a node to get line id column numbers associated with the message.
      frame - the class frame where the violation is found.

    • 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.

    • isInCompactConstructor

      private static boolean isInCompactConstructor(DetailAST ast)
      Return whether ast is in a COMPACT_CTOR_DEF.
      Parameters:
      ast - The token to check
      Returns:
      true if ast is in a COMPACT_CTOR_DEF, false otherwise

    • collectDeclarations

      private static void collectDeclarations(Deque<RequireThisCheck.AbstractFrame> frameStack, DetailAST ast)
      Parses the next AST for declarations.
      Parameters:
      frameStack - stack containing the FrameTree being built.
      ast - AST to parse.

    • collectVariableDeclarations

      private static void collectVariableDeclarations(DetailAST ast, RequireThisCheck.AbstractFrame frame)
      Collects variable declarations.
      Parameters:
      ast - variable token.
      frame - current frame.

    • collectMethodDeclarations

      private static void collectMethodDeclarations(Deque<RequireThisCheck.AbstractFrame> frameStack, DetailAST ast, RequireThisCheck.AbstractFrame frame)
      Collects METHOD_DEF declarations.
      Parameters:
      frameStack - stack containing the FrameTree being built.
      ast - AST to parse.
      frame - current frame.

    • endCollectingDeclarations

      private void endCollectingDeclarations(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.

    • getClassFrameWhereViolationIsFound

      @Nullable 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.

    • isViolationNoOverlapping

      private boolean isViolationNoOverlapping(DetailAST ast)
      Checks if a violation occurred for a CLASS_FRAME when not overlapping.
      Parameters:
      ast - IDENT ast to check.
      Returns:
      true if a violation occurred.

    • isViolationForBlockFrame

      private boolean isViolationForBlockFrame(DetailAST ast, RequireThisCheck.AbstractFrame variableDeclarationFrame)
      Checks if a violation occurred for a BLOCK_FRAME.
      Parameters:
      ast - IDENT ast to check.
      variableDeclarationFrame - the frame where the variable is declared.
      Returns:
      true if a violation occurred.

    • getFrameForMethod

      private RequireThisCheck.AbstractFrame getFrameForMethod(DetailAST ast, RequireThisCheck.AbstractFrame variableDeclarationFrame)
      Returns the class frame where violation is found (where the field is used without 'this') or null otherwise.
      Parameters:
      ast - IDENT ast to check.
      variableDeclarationFrame - the frame where the variable is declared.
      Returns:
      the class frame where violation is found or null otherwise.

    • isViolationForMethodOverlapping

      private boolean isViolationForMethodOverlapping(DetailAST ast, RequireThisCheck.AbstractFrame variableDeclarationFrame)
      Checks if a violation occurred for a METHOD_FRAME when overlapping.
      Parameters:
      ast - IDENT ast to check.
      variableDeclarationFrame - the frame where the variable is declared.
      Returns:
      true if a violation occurred.

    • isViolationForMethodNoOverlapping

      private boolean isViolationForMethodNoOverlapping(DetailAST ast, RequireThisCheck.AbstractFrame variableDeclarationFrame)
      Checks if a violation occurred for a METHOD_FRAME when not overlapping.
      Parameters:
      ast - IDENT ast to check.
      variableDeclarationFrame - the frame where the variable is declared.
      Returns:
      true if a violation occurred.

    • 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.

    • 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.

    • 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.

    • isAstInside

      private static boolean isAstInside(DetailAST tree, DetailAST ast)
      Checks if the given ast is equal to the tree or a child of it.
      Parameters:
      tree - The tree to search.
      ast - The AST to look for.
      Returns:
      true if the ast was found.

    • canBeReferencedFromStaticContext

      private static 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.

    • 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.

    • 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.

    • 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.

    • 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.

    • getAllTokensOfType

      private static 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.

    • getAllTokensOfType

      private static 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.

    • getAllTokensWhichAreEqualToCurrent

      private static 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.

    • 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.

    • 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.

    • 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.

    • 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.

    • getNearestClassFrameName

      private String getNearestClassFrameName()
      Gets the name of the nearest parent ClassFrame.
      Returns:
      the name of the nearest parent ClassFrame.

    • isLambdaParameter

      private static boolean isLambdaParameter(DetailAST ast)
      Checks if the token is a Lambda parameter.
      Parameters:
      ast - the DetailAST value of the token to be checked
      Returns:
      true if the token is a Lambda parameter

    • isMatchingLambdaParam

      private static boolean isMatchingLambdaParam(DetailAST ast, DetailAST lambda)
      Checks whether the given AST matches a parameter of the specified lambda.
      Parameters:
      ast - the AST node to check.
      lambda - the lambda expression AST node.
      Returns:
      true if the AST matches a lambda parameter.

    • isInsideTypeDefInsideLambda

      private static boolean isInsideTypeDefInsideLambda(DetailAST ast)
      Checks if the given AST is inside a type declaration (class, interface, enum, record, or anonymous class) that is nested within the enclosing lambda.
      Parameters:
      ast - the AST node to check.
      Returns:
      true if there is a type declaration boundary between ast and the lambda.

    • isAstSimilar

      private static boolean isAstSimilar(DetailAST left, DetailAST right)
      Checks if 2 AST are similar by their type and text.
      Parameters:
      left - The first AST to check.
      right - The second AST to check.
      Returns:
      true if they are similar.