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

Class FinalLocalVariableCheck

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.FinalLocalVariableCheck
All Implemented Interfaces:
Configurable, Contextualizable
public class FinalLocalVariableCheck extends AbstractCheck
Checks that local variables that never have their values changed are declared final. The check can be configured to also check that unchanged parameters are declared final.

When configured to check parameters, the check ignores parameters of interface methods and abstract methods.

  • Property validateEnhancedForLoopVariable - Control whether to check enhanced for-loop variable. Type is boolean. Default value is false.
  • Property validateUnnamedVariables - Control whether to check unnamed variables. Type is boolean. Default value is false.
  • Property tokens - tokens to check Type is java.lang.String[]. Validation type is tokenSet. Default value is: VARIABLE_DEF.

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

  • final.variable
Since:
3.2

  • Field Details

  • Constructor Details

  • Method Details

    • setValidateEnhancedForLoopVariable

      public final void setValidateEnhancedForLoopVariable(boolean validateEnhancedForLoopVariable)
      Setter to control whether to check enhanced for-loop variable.
      Parameters:
      validateEnhancedForLoopVariable - whether to check for-loop variable
      Since:
      6.5

    • setValidateUnnamedVariables

      public final void setValidateUnnamedVariables(boolean validateUnnamedVariables)
      Setter to control whether to check unnamed variables.
      Parameters:
      validateUnnamedVariables - whether to check unnamed variables
      Since:
      10.18.0

    • 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:

    • 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:

    • 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:

    • 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

    • updateCurrentScopeAssignedVariables

      private void updateCurrentScopeAssignedVariables()
      Update assigned variables in a temporary stack.

    • determineAssignmentConditions

      private static void determineAssignmentConditions(DetailAST ident, FinalLocalVariableCheck.FinalVariableCandidate candidate)
      Determines identifier assignment conditions (assigned or already assigned).
      Parameters:
      ident - identifier.
      candidate - final local variable candidate.

    • isInSpecificCodeBlocks

      private static boolean isInSpecificCodeBlocks(DetailAST node, int... blockTypes)
      Checks whether the scope of a node is restricted to a specific code blocks.
      Parameters:
      node - node.
      blockTypes - int array of all block types to check.
      Returns:
      true if the scope of a node is restricted to specific code block types.

    • getFinalCandidate

      private Optional<FinalLocalVariableCheck.FinalVariableCandidate> getFinalCandidate(DetailAST ast)
      Gets final variable candidate for ast.
      Parameters:
      ast - ast.
      Returns:
      Optional of FinalLocalVariableCheck.FinalVariableCandidate for ast from scopeStack.

    • storePrevScopeUninitializedVariableData

      private void storePrevScopeUninitializedVariableData()
      Store un-initialized variables in a temporary stack for future use.

    • updateAllUninitializedVariables

      private void updateAllUninitializedVariables()
      Update current scope data uninitialized variable according to the whole scope data.

    • updateUninitializedVariables

      private void updateUninitializedVariables(Deque<DetailAST> scopeUninitializedVariableData)
      Update current scope data uninitialized variable according to the specific scope data.
      Parameters:
      scopeUninitializedVariableData - variable for specific stack of uninitialized variables

    • shouldUpdateUninitializedVariables

      private static boolean shouldUpdateUninitializedVariables(DetailAST ast)
      If there is an else following or token is CASE_GROUP or SWITCH_RULE and there is another case following, then update the uninitialized variables.
      Parameters:
      ast - token to be checked
      Returns:
      true if should be updated, else false

    • isCaseTokenWithAnotherCaseFollowing

      private static boolean isCaseTokenWithAnotherCaseFollowing(DetailAST ast)
      If token is CASE_GROUP or SWITCH_RULE and there is another case following.
      Parameters:
      ast - token to be checked
      Returns:
      true if token is CASE_GROUP or SWITCH_RULE and there is another case following, else false

    • findLastCaseGroupWhichContainsSlist

      private static DetailAST findLastCaseGroupWhichContainsSlist(DetailAST literalSwitchAst)
      Returns the last token of type TokenTypes.CASE_GROUP which contains TokenTypes.SLIST.
      Parameters:
      literalSwitchAst - ast node of type TokenTypes.LITERAL_SWITCH
      Returns:
      the matching token, or null if no match

    • shouldCheckEnhancedForLoopVariable

      private boolean shouldCheckEnhancedForLoopVariable(DetailAST ast)
      Determines whether enhanced for-loop variable should be checked or not.
      Parameters:
      ast - The ast to compare.
      Returns:
      true if enhanced for-loop variable should be checked.

    • shouldCheckUnnamedVariable

      private boolean shouldCheckUnnamedVariable(DetailAST ast)
      Determines whether unnamed variable should be checked or not.
      Parameters:
      ast - The ast to compare.
      Returns:
      true if unnamed variable should be checked.

    • insertParameter

      private void insertParameter(DetailAST ast)
      Insert a parameter at the topmost scope stack.
      Parameters:
      ast - the variable to insert.

    • insertVariable

      private void insertVariable(DetailAST ast)
      Insert a variable at the topmost scope stack.
      Parameters:
      ast - the variable to insert.

    • isInitialized

      private static boolean isInitialized(DetailAST ast)
      Check if VARIABLE_DEF is initialized or not.
      Parameters:
      ast - VARIABLE_DEF to be checked
      Returns:
      true if initialized

    • isFirstChild

      private static boolean isFirstChild(DetailAST ast)
      Whether the ast is the first child of its parent.
      Parameters:
      ast - the ast to check.
      Returns:
      true if the ast is the first child of its parent.

    • removeFinalVariableCandidateFromStack

      private void removeFinalVariableCandidateFromStack(DetailAST ast)
      Removes the final variable candidate from the Stack.
      Parameters:
      ast - variable to remove.

    • isMultipleTypeCatch

      private static boolean isMultipleTypeCatch(DetailAST parameterDefAst)
      Check if given parameter definition is a multiple type catch.
      Parameters:
      parameterDefAst - parameter definition
      Returns:
      true if it is a multiple type catch, false otherwise

    • shouldRemoveFinalVariableCandidate

      private static boolean shouldRemoveFinalVariableCandidate(FinalLocalVariableCheck.ScopeData scopeData, DetailAST ast)
      Whether the final variable candidate should be removed from the list of final local variable candidates.
      Parameters:
      scopeData - the scope data of the variable.
      ast - the variable ast.
      Returns:
      true, if the variable should be removed.

    • getParentLoop

      private static DetailAST getParentLoop(DetailAST ast)
      Get the ast node of type LOOP_TYPES that is the ancestor of the current ast node, if there is no such node, null is returned.
      Parameters:
      ast - ast node
      Returns:
      ast node of type LOOP_TYPES that is the ancestor of the current ast node, null if no such node exists

    • isAssignOperator

      private static boolean isAssignOperator(int parentType)
      Is Arithmetic operator.
      Parameters:
      parentType - token AST
      Returns:
      true is token type is in arithmetic operator

    • isVariableInForInit

      private static boolean isVariableInForInit(DetailAST variableDef)
      Checks if current variable is defined in for-loop init, e.g.:

      for (int i = 0, j = 0; i < j; i++) { . . . }

      i, j are defined in for-loop init
      Parameters:
      variableDef - variable definition node.
      Returns:
      true if variable is defined in for-loop init

    • isInMethodWithoutBody

      private static boolean isInMethodWithoutBody(DetailAST parameterDefAst)
      Checks if a parameter is within a method that has no implementation body.
      Parameters:
      parameterDefAst - the AST node representing the parameter definition
      Returns:
      true if the parameter is in a method without a body

    • isInLambda

      private static boolean isInLambda(DetailAST paramDef)
      Check if current param is lambda's param.
      Parameters:
      paramDef - parameter def.
      Returns:
      true if current param is lambda's param.

    • findFirstUpperNamedBlock

      private static DetailAST findFirstUpperNamedBlock(DetailAST ast)
      Find the Class, Constructor, Enum, Method, or Field in which it is defined.
      Parameters:
      ast - Variable for which we want to find the scope in which it is defined
      Returns:
      ast The Class or Constructor or Method in which it is defined.

    • isSameVariables

      private static boolean isSameVariables(DetailAST ast1, DetailAST ast2)
      Check if both the Variables are same.
      Parameters:
      ast1 - Variable to compare
      ast2 - Variable to compare
      Returns:
      true if both the variables are same, otherwise false

    • isLoopAst

      private static boolean isLoopAst(int ast)
      Checks whether the ast is a loop.
      Parameters:
      ast - the ast to check.
      Returns:
      true if the ast is a loop.