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

Class HiddenFieldCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable
    public class HiddenFieldCheck
extends AbstractCheck

    Checks that a local variable or a parameter does not shadow a field that is defined in the same class.

    It is possible to configure the check to ignore all property setter methods.

    A method is recognized as a setter if it is in the following form 

     ${returnType} set${Name}(${anyType} ${name}) { ... }

    where ${anyType} is any primitive type, class or interface name; ${name} is name of the variable that is being set and ${Name} its capitalized form that appears in the method name. By default it is expected that setter returns void, i.e. ${returnType} is 'void'. For example 

     void setTime(long time) { ... }

    Any other return types will not let method match a setter pattern. However, by setting setterCanReturnItsClass property to true definition of a setter is expanded, so that setter return type can also be a class in which setter is declared. For example 

     class PageBuilder {
   PageBuilder setName(String name) { ... }
 }

    Such methods are known as chain-setters and a common when Builder-pattern is used. Property setterCanReturnItsClass has effect only if ignoreSetter is set to true.

    • Property ignoreFormat - Define the RegExp for names of variables and parameters to ignore. Type is java.util.regex.Pattern. Default value is null.
    • Property ignoreConstructorParameter - Control whether to ignore constructor parameters. Type is boolean. Default value is false.
    • Property ignoreSetter - Allow to ignore the parameter of a property setter method. Type is boolean. Default value is false.
    • Property setterCanReturnItsClass - Allow to expand the definition of a setter method to include methods that return the class' instance. Type is boolean. Default value is false.
    • Property ignoreAbstractMethods - Control whether to ignore parameters of abstract methods. 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, PARAMETER_DEF, PATTERN_VARIABLE_DEF, LAMBDA, RECORD_COMPONENT_DEF.

    To configure the check: 

      <module name="HiddenField"/>

    To configure the check so that it checks local variables but not parameters: 

     <module name="HiddenField">
   <property name="tokens" value="VARIABLE_DEF"/>
 </module>

    To configure the check so that it ignores the variables and parameters named "test": 

     <module name="HiddenField">
   <property name="ignoreFormat" value="^test$"/>
 </module>
 
     class SomeClass
 {
   private List<String> test;

   private void addTest(List<String> test) // no violation
   {
     this.test.addAll(test);
   }

   private void foo()
   {
     final List<String> test = new ArrayList<>(); // no violation
     ...
   }
 }

    To configure the check so that it ignores constructor parameters: 

     <module name="HiddenField">
   <property name="ignoreConstructorParameter" value="true"/>
 </module>

    To configure the check so that it ignores the parameter of setter methods: 

     <module name="HiddenField">
   <property name="ignoreSetter" value="true"/>
 </module>

    To configure the check so that it ignores the parameter of setter methods recognizing setter as returning either void or a class in which it is declared: 

     <module name="HiddenField">
   <property name="ignoreSetter" value="true"/>
   <property name="setterCanReturnItsClass" value="true"/>
 </module>

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • hidden.field
    Since:
    3.0

    • Field Detail

      • MSG_KEY

        public static final java.lang.String MSG_KEY
        A key is pointing to the warning message text in "messages.properties" file.
        See Also:
        Constant Field Values

    • Constructor Detail

      • HiddenFieldCheck

        public HiddenFieldCheck()

    • Method Detail

      • 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:
        TokenTypes

      • 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:
        TokenTypes

      • 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:
        TokenTypes

      • 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

      • 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

      • setIgnoreFormat

        public void setIgnoreFormat​(java.util.regex.Pattern pattern)
        Setter to define the RegExp for names of variables and parameters to ignore.
        Parameters:
        pattern - a pattern.

      • setIgnoreSetter

        public void setIgnoreSetter​(boolean ignoreSetter)
        Setter to allow to ignore the parameter of a property setter method.
        Parameters:
        ignoreSetter - decide whether to ignore the parameter of a property setter method.

      • setSetterCanReturnItsClass

        public void setSetterCanReturnItsClass​(boolean aSetterCanReturnItsClass)
        Setter to allow to expand the definition of a setter method to include methods that return the class' instance.
        Parameters:
        aSetterCanReturnItsClass - if true then setter can return either void or class in which it is declared. If false then in order to be recognized as setter method (otherwise already recognized as a setter) must return void. Later is the default behavior.

      • setIgnoreConstructorParameter

        public void setIgnoreConstructorParameter​(boolean ignoreConstructorParameter)
        Setter to control whether to ignore constructor parameters.
        Parameters:
        ignoreConstructorParameter - decide whether to ignore constructor parameters.

      • setIgnoreAbstractMethods

        public void setIgnoreAbstractMethods​(boolean ignoreAbstractMethods)
        Setter to control whether to ignore parameters of abstract methods.
        Parameters:
        ignoreAbstractMethods - decide whether to ignore parameters of abstract methods.