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

Class IllegalTypeCheck

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.IllegalTypeCheck
All Implemented Interfaces:
Configurable, Contextualizable
public final class IllegalTypeCheck extends AbstractCheck
Checks that particular classes or interfaces are never used.

Rationale: Helps reduce coupling on concrete classes.

For additional restriction of type usage see also: IllegalInstantiation, IllegalImport

It is possible to set illegal class names via short or canonical name. Specifying illegal type invokes analyzing imports and Check puts violations at corresponding declarations (of variables, methods or parameters). This helps to avoid ambiguous cases, e.g.: java.awt.List was set as illegal class name, then, code like: 

 import java.util.List;
 ...
 List list; //No violation here

will be ok.

In most cases it's justified to put following classes to illegalClassNames:

  • GregorianCalendar
  • Hashtable
  • ArrayList
  • LinkedList
  • Vector

as methods that are differ from interface methods are rarely used, so in most cases user will benefit from checking for them.

  • Property ignoredMethodNames - Specify methods that should not be checked. Type is java.lang.String[]. Default value is getEnvironment, getInitialContext.
  • Property illegalAbstractClassNameFormat - Specify RegExp for illegal abstract class names. Type is java.util.regex.Pattern. Default value is "^(.*[.])?Abstract.*$".
  • Property illegalClassNames - Specify classes that should not be used as types in variable declarations, return values or parameters. Type is java.lang.String[]. Default value is HashMap, HashSet, LinkedHashMap, LinkedHashSet, TreeMap, TreeSet, java.util.HashMap, java.util.HashSet, java.util.LinkedHashMap, java.util.LinkedHashSet, java.util.TreeMap, java.util.TreeSet.
  • Property legalAbstractClassNames - Define abstract classes that may be used as types. Type is java.lang.String[]. Default value is "".
  • Property memberModifiers - Control whether to check only methods and fields with any of the specified modifiers. This property does not affect method calls nor method references nor record components. Type is java.lang.String[]. Validation type is tokenTypesSet. Default value is "".
  • Property validateAbstractClassNames - Control whether to validate abstract class names. Type is boolean. Default value is false.
  • Property tokens - tokens to check Type is java.lang.String[]. Validation type is tokenSet. Default value is: ANNOTATION_FIELD_DEF, CLASS_DEF, INTERFACE_DEF, METHOD_CALL, METHOD_DEF, METHOD_REF, PARAMETER_DEF, VARIABLE_DEF, PATTERN_VARIABLE_DEF, RECORD_DEF, RECORD_COMPONENT_DEF, RECORD_PATTERN_DEF.

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

  • illegal.type
Since:
3.2

  • Field Details

  • Constructor Details

    • IllegalTypeCheck

      public IllegalTypeCheck()
      Creates new instance of the check.

  • Method Details

    • setIllegalAbstractClassNameFormat

      public void setIllegalAbstractClassNameFormat(Pattern pattern)
      Setter to specify RegExp for illegal abstract class names.
      Parameters:
      pattern - a pattern.
      Since:
      3.2

    • setValidateAbstractClassNames

      public void setValidateAbstractClassNames(boolean validateAbstractClassNames)
      Setter to control whether to validate abstract class names.
      Parameters:
      validateAbstractClassNames - whether abstract class names must be ignored.
      Since:
      6.10

    • 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:

    • 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

    • 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:

    • 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

    • isVerifiable

      private boolean isVerifiable(DetailAST methodOrVariableDef)
      Checks if current method's return type or variable's type is verifiable according to memberModifiers option.
      Parameters:
      methodOrVariableDef - METHOD_DEF or VARIABLE_DEF ast node.
      Returns:
      true if member is verifiable according to memberModifiers option.

    • isContainVerifiableType

      private boolean isContainVerifiableType(DetailAST modifiers)
      Checks is modifiers contain verifiable type.
      Parameters:
      modifiers - parent node for all modifiers
      Returns:
      true if method or variable can be verified

    • visitTypeDef

      private void visitTypeDef(DetailAST typeDef)
      Checks the super type and implemented interfaces of a given type.
      Parameters:
      typeDef - class or interface for check.

    • visitMethodDef

      private void visitMethodDef(DetailAST methodDef)
      Checks return type of a given method.
      Parameters:
      methodDef - method for check.

    • visitParameterDef

      private void visitParameterDef(DetailAST parameterDef)
      Checks type of parameters.
      Parameters:
      parameterDef - parameter list for check.

    • visitVariableDef

      private void visitVariableDef(DetailAST variableDef)
      Checks type of given variable.
      Parameters:
      variableDef - variable to check.

    • visitMethodCallOrRef

      private void visitMethodCallOrRef(DetailAST methodCallOrRef)
      Checks the type arguments of given method call/reference.
      Parameters:
      methodCallOrRef - method call/reference to check.

    • visitImport

      private void visitImport(DetailAST importAst)
      Checks imported type (as static and star imports are not supported by Check, only type is in the consideration).
      If this type is illegal due to Check's options - puts violation on it.
      Parameters:
      importAst - Import

    • isStarImport

      private static boolean isStarImport(DetailAST importAst)
      Checks if current import is star import. E.g.:

      import java.util.*;

      Parameters:
      importAst - Import
      Returns:
      true if it is star import

    • checkClassName

      private void checkClassName(DetailAST ast)
      Checks type and type arguments/parameters of given method, parameter, variable or method call/reference.
      Parameters:
      ast - node to check.

    • checkIdent

      private void checkIdent(DetailAST type)
      Checks the identifier of the given type.
      Parameters:
      type - node to check.

    • checkBaseTypes

      private void checkBaseTypes(DetailAST clause)
      Checks the extends or implements statement.
      Parameters:
      clause - DetailAST for either TokenTypes.EXTENDS_CLAUSE or TokenTypes.IMPLEMENTS_CLAUSE

    • checkType

      private void checkType(DetailAST type)
      Checks the given type, its arguments and parameters.
      Parameters:
      type - node to check.

    • checkTypeBounds

      private void checkTypeBounds(DetailAST type)
      Checks the upper and lower bounds for the given type.
      Parameters:
      type - node to check.

    • checkTypeParameters

      private void checkTypeParameters(DetailAST node)
      Checks the type parameters of the node.
      Parameters:
      node - node to check.

    • checkTypeArguments

      private void checkTypeArguments(DetailAST node)
      Checks the type arguments of the node.
      Parameters:
      node - node to check.

    • isMatchingClassName

      private boolean isMatchingClassName(String className)
      Returns true if given class name is one of illegal classes or else false.
      Parameters:
      className - class name to check.
      Returns:
      true if given class name is one of illegal classes or if it matches to abstract class names pattern.

    • extendIllegalClassNamesWithShortName

      private void extendIllegalClassNamesWithShortName(String canonicalName)
      Extends illegal class names set via imported short type name.
      Parameters:
      canonicalName - Canonical name of imported type.

    • getImportedTypeCanonicalName

      private static String getImportedTypeCanonicalName(DetailAST importAst)
      Gets imported type's canonical name.
      Parameters:
      importAst - Import
      Returns:
      Imported canonical type's name.

    • getNextSubTreeNode

      private static DetailAST getNextSubTreeNode(DetailAST currentNodeAst, DetailAST subTreeRootAst)
      Gets the next node of a syntactical tree (child of a current node or sibling of a current node, or sibling of a parent of a current node).
      Parameters:
      currentNodeAst - Current node in considering
      subTreeRootAst - SubTree root
      Returns:
      Current node after bypassing, if current node reached the root of a subtree method returns null

    • isCheckedMethod

      private boolean isCheckedMethod(DetailAST ast)
      Returns true if method has to be checked or false.
      Parameters:
      ast - method def to check.
      Returns:
      true if we should check this method.

    • setIllegalClassNames

      public void setIllegalClassNames(String... classNames)
      Setter to specify classes that should not be used as types in variable declarations, return values or parameters.
      Parameters:
      classNames - array of illegal variable types
      Since:
      3.2

    • setIgnoredMethodNames

      public void setIgnoredMethodNames(String... methodNames)
      Setter to specify methods that should not be checked.
      Parameters:
      methodNames - array of ignored method names
      Since:
      3.2

    • setLegalAbstractClassNames

      public void setLegalAbstractClassNames(String... classNames)
      Setter to define abstract classes that may be used as types.
      Parameters:
      classNames - array of legal abstract class names
      Since:
      4.2

    • setMemberModifiers

      public void setMemberModifiers(String modifiers)
      Setter to control whether to check only methods and fields with any of the specified modifiers. This property does not affect method calls nor method references nor record components.
      Parameters:
      modifiers - String contains modifiers.
      Since:
      6.3