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

Class PackageDeclarationCheck

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

    Ensures that a class has a package declaration, and (optionally) whether the package name matches the directory name for the source file.

    Rationale: Classes that live in the null package cannot be imported. Many novice developers are not aware of this.

    Packages provide logical namespace to classes and should be stored in the form of directory levels to provide physical grouping to your classes. These directories are added to the classpath so that your classes are visible to JVM when it runs the code.

    • Property matchDirectoryStructure - Control whether to check for directory and package name match. Type is boolean. Default value is true.

    To configure the check: 

     <module name="PackageDeclaration"/>

    Let us consider the class AnnotationLocationCheck which is in the directory /com/puppycrawl/tools/checkstyle/checks/annotations/ 

     package com.puppycrawl.tools.checkstyle.checks; //Violation
 public class AnnotationLocationCheck extends AbstractCheck {
   //...
 }

    Example of how the check works when matchDirectoryStructure option is set to false. Let us again consider the AnnotationLocationCheck class located at directory /com/puppycrawl/tools/checkstyle/checks/annotations/ along with the following setup, 

     <module name="PackageDeclaration">
 <property name="matchDirectoryStructure" value="false"/>
 </module>
 
     package com.puppycrawl.tools.checkstyle.checks;  //No Violation

 public class AnnotationLocationCheck extends AbstractCheck {
   //...
 }

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • mismatch.package.directory
    • missing.package.declaration
    Since:
    3.2

    • Field Detail

      • MSG_KEY_MISSING

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

      • MSG_KEY_MISMATCH

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

    • Constructor Detail

      • PackageDeclarationCheck

        public PackageDeclarationCheck()

    • Method Detail

      • setMatchDirectoryStructure

        public void setMatchDirectoryStructure​(boolean matchDirectoryStructure)
        Setter to control whether to check for directory and package name match.
        Parameters:
        matchDirectoryStructure - the new value.

      • 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

      • 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

      • 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

      • beginTree

        public void beginTree​(DetailAST ast)
        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:
        ast - the root of the tree

      • finishTree

        public void finishTree​(DetailAST ast)
        Description copied from class: AbstractCheck
        Called after finished processing a tree. Ideal place to report on information collected whilst processing a tree.
        Overrides:
        finishTree in class AbstractCheck
        Parameters:
        ast - the root of the tree