Class DeclarationOrderCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable

    public class DeclarationOrderCheck
    extends AbstractCheck

    Checks that the parts of a class, record, or interface declaration appear in the order suggested by the Code Conventions for the Java Programming Language.

    According to Code Conventions for the Java Programming Language, the parts of a class or interface declaration should appear in the following order:

    1. Class (static) variables. First the public class variables, then protected, then package level (no access modifier), and then private.
    2. Instance variables. First the public class variables, then protected, then package level (no access modifier), and then private.
    3. Constructors
    4. Methods

    Purpose of ignore* option is to ignore related violations, however it still impacts on other class members.

    ATTENTION: the check skips class fields which have forward references from validation due to the fact that we have Checkstyle's limitations to clearly detect user intention of fields location and grouping. For example:

     public class A {
       private double x = 1.0;
       private double y = 2.0;
       public double slope = x / y; // will be skipped from validation due to forward reference
     }
     
    • Property ignoreConstructors - control whether to ignore constructors. Type is boolean. Default value is false.
    • Property ignoreModifiers - control whether to ignore modifiers (fields, ...). Type is boolean. Default value is false.

    To configure the check:

     <module name="DeclarationOrder"/>
     

    Example:

     public class Test {
    
       public int a;
       protected int b;
       public int c;            // violation, variable access definition in wrong order
    
       Test() {
         this.a = 0;
       }
    
       public void foo() {
         // This method does nothing
       }
    
       Test(int a) {            // violation, constructor definition in wrong order
         this.a = a;
       }
    
       private String name;     // violation, instance variable declaration in wrong order
     }
     

    To configure the check to ignore validation of constructors:

     <module name="DeclarationOrder">
       <property name="ignoreConstructors" value="true"/>
     </module>
     

    Example:

     public class Test {
    
       public int a;
       protected int b;
       public int c;            // violation, variable access definition in wrong order
    
       Test() {
         this.a = 0;
       }
    
       public void foo() {
         // This method does nothing
       }
    
       Test(int a) {            // OK, validation of constructors ignored
         this.a = a;
       }
    
       private String name;     // violation, instance variable declaration in wrong order
     }
     

    To configure the check to ignore modifiers:

     <module name="DeclarationOrder">
       <property name="ignoreModifiers" value="true"/>
     </module>
     

    Example:

     public class Test {
    
       public int a;
       protected int b;
       public int c;            // OK, access modifiers not considered while validating
    
       Test() {
         this.a = 0;
       }
    
       public void foo() {
         // This method does nothing
       }
    
       Test(int a) {            // violation, constructor definition in wrong order
         this.a = a;
       }
    
       private String name;     // violation, instance variable declaration in wrong order
     }
     

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • declaration.order.access
    • declaration.order.constructor
    • declaration.order.instance
    • declaration.order.static
    Since:
    3.2
    • Field Detail

      • MSG_CONSTRUCTOR

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

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

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

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

        private static final int STATE_STATIC_VARIABLE_DEF
        State for the VARIABLE_DEF.
        See Also:
        Constant Field Values
      • STATE_INSTANCE_VARIABLE_DEF

        private static final int STATE_INSTANCE_VARIABLE_DEF
        State for the VARIABLE_DEF.
        See Also:
        Constant Field Values
      • STATE_CTOR_DEF

        private static final int STATE_CTOR_DEF
        State for the CTOR_DEF.
        See Also:
        Constant Field Values
      • STATE_METHOD_DEF

        private static final int STATE_METHOD_DEF
        State for the METHOD_DEF.
        See Also:
        Constant Field Values
      • scopeStates

        private java.util.Deque<DeclarationOrderCheck.ScopeState> scopeStates
        List of Declaration States. This is necessary due to inner classes that have their own state.
      • classFieldNames

        private java.util.Set<java.lang.String> classFieldNames
        Set of all class field names.
      • ignoreConstructors

        private boolean ignoreConstructors
        Control whether to ignore constructors.
      • ignoreModifiers

        private boolean ignoreModifiers
        Control whether to ignore modifiers (fields, ...).
    • Constructor Detail

      • DeclarationOrderCheck

        public DeclarationOrderCheck()
    • 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
      • processConstructor

        private void processConstructor​(DetailAST ast)
        Processes constructor.
        Parameters:
        ast - constructor AST.
      • processModifiers

        private void processModifiers​(DetailAST ast)
        Processes modifiers.
        Parameters:
        ast - ast of Modifiers.
      • processModifiersState

        private boolean processModifiersState​(DetailAST modifierAst,
                                              DeclarationOrderCheck.ScopeState state)
        Process if given modifiers are appropriate in given state (STATE_STATIC_VARIABLE_DEF, STATE_INSTANCE_VARIABLE_DEF, (STATE_CTOR_DEF, STATE_METHOD_DEF), if it is it updates states where appropriate or logs violation.
        Parameters:
        modifierAst - modifiers to process
        state - current state
        Returns:
        true if modifierAst is valid in given state, false otherwise
      • processModifiersSubState

        private void processModifiersSubState​(DetailAST modifiersAst,
                                              DeclarationOrderCheck.ScopeState state,
                                              boolean isStateValid)
        Checks if given modifiers are valid in substate of given state(Scope), if it is it updates substate or else it logs violation.
        Parameters:
        modifiersAst - modifiers to process
        state - current state
        isStateValid - is main state for given modifiers is valid
      • isForwardReference

        private boolean isForwardReference​(DetailAST fieldDef)
        Checks whether an identifier references a field which has been already defined in class.
        Parameters:
        fieldDef - a field definition.
        Returns:
        true if an identifier references a field which has been already defined in class.
      • 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.
      • 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
      • setIgnoreConstructors

        public void setIgnoreConstructors​(boolean ignoreConstructors)
        Setter to control whether to ignore constructors.
        Parameters:
        ignoreConstructors - whether to ignore constructors.
      • setIgnoreModifiers

        public void setIgnoreModifiers​(boolean ignoreModifiers)
        Setter to control whether to ignore modifiers (fields, ...).
        Parameters:
        ignoreModifiers - whether to ignore modifiers.