Package com.puppycrawl.tools.checkstyle.checks.imports

Class UnusedImportsCheck

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

    Checks for unused import statements.

    An example of how to configure the check is: 

     <module name="UnusedImports"/>
    Compatible with Java 1.5 source.

    • 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

      • CLASS_NAME

        private static final java.util.regex.Pattern CLASS_NAME
        Regex to match class names.

      • FIRST_CLASS_NAME

        private static final java.util.regex.Pattern FIRST_CLASS_NAME
        Regex to match the first class name.

      • ARGUMENT_NAME

        private static final java.util.regex.Pattern ARGUMENT_NAME
        Regex to match argument names.

      • JAVA_LANG_PACKAGE_PATTERN

        private static final java.util.regex.Pattern JAVA_LANG_PACKAGE_PATTERN
        Regexp pattern to match java.lang package.

      • STAR_IMPORT_SUFFIX

        private static final java.lang.String STAR_IMPORT_SUFFIX
        Suffix for the star import.
        See Also:
        Constant Field Values

      • imports

        private final java.util.Set<FullIdent> imports
        Set of the imports.

      • referenced

        private final java.util.Set<java.lang.String> referenced
        Set of references - possibly to imports or other things.

      • collect

        private boolean collect
        Flag to indicate when time to start collecting references.

      • processJavadoc

        private boolean processJavadoc
        Flag whether to process Javadoc comments.

    • Constructor Detail

      • UnusedImportsCheck

        public UnusedImportsCheck()

    • Method Detail

      • setProcessJavadoc

        public void setProcessJavadoc​(boolean value)
        Sets whether to process JavaDoc or not.
        Parameters:
        value - Flag for processing JavaDoc.

      • 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

      • finishTree

        public void finishTree​(DetailAST rootAST)
        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:
        rootAST - the root of the tree

      • 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

      • isUnusedImport

        private boolean isUnusedImport​(java.lang.String imprt)
        Checks whether an import is unused.
        Parameters:
        imprt - an import.
        Returns:
        true if an import is unused.

      • processIdent

        private void processIdent​(DetailAST ast)
        Collects references made by IDENT.
        Parameters:
        ast - the IDENT node to process

      • processImport

        private void processImport​(DetailAST ast)
        Collects the details of imports.
        Parameters:
        ast - node containing the import details

      • processStaticImport

        private void processStaticImport​(DetailAST ast)
        Collects the details of static imports.
        Parameters:
        ast - node containing the static import details

      • collectReferencesFromJavadoc

        private void collectReferencesFromJavadoc​(DetailAST ast)
        Collects references made in Javadoc comments.
        Parameters:
        ast - node to inspect for Javadoc

      • collectReferencesFromJavadoc

        private static java.util.Set<java.lang.String> collectReferencesFromJavadoc​(TextBlock textBlock)
        Process a javadoc TextBlock and return the set of classes referenced within.
        Parameters:
        textBlock - The javadoc block to parse
        Returns:
        a set of classes referenced in the javadoc block

      • getValidTags

        private static java.util.List<JavadocTag> getValidTags​(TextBlock cmt,
                                                       JavadocUtils.JavadocTagType tagType)
        Returns the list of valid tags found in a javadoc TextBlock.
        Parameters:
        cmt - The javadoc block to parse
        tagType - The type of tags we're interested in
        Returns:
        the list of tags

      • processJavadocTag

        private static java.util.Set<java.lang.String> processJavadocTag​(JavadocTag tag)
        Returns a list of references found in a javadoc JavadocTag.
        Parameters:
        tag - The javadoc tag to parse
        Returns:
        A list of references found in this tag

      • matchPattern

        private static java.util.Set<java.lang.String> matchPattern​(java.lang.String identifier,
                                                            java.util.regex.Pattern pattern)
        Extracts a list of texts matching a Pattern from a String.
        Parameters:
        identifier - The String to match the pattern against
        pattern - The Pattern used to extract the texts
        Returns:
        A list of texts which matched the pattern