Package com.puppycrawl.tools.checkstyle.checks.whitespace

Class GenericWhitespaceCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable
    public class GenericWhitespaceCheck
extends AbstractCheck
    Checks that the whitespace around the Generic tokens (angle brackets) "<" and ">" are correct to the typical convention. The convention is not configurable.

    Left angle bracket ("<"):

    • should be preceded with whitespace only in generic methods definitions.
    • should not be preceded with whitespace when it is preceded method name or constructor.
    • should not be preceded with whitespace when following type name.
    • should not be followed with whitespace in all cases.

    Right angle bracket (">"):

    • should not be preceded with whitespace in all cases.
    • should be followed with whitespace in almost all cases, except diamond operators and when preceding a method name, constructor, or record header.

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • ws.followed
    • ws.illegalFollow
    • ws.notPreceded
    • ws.preceded
    Since:
    5.0

    • Method Detail

      • 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 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

      • processEnd

        private void processEnd​(DetailAST ast)
        Checks the token for the end of Generics.
        Parameters:
        ast - the token to check

      • processNestedGenerics

        private void processNestedGenerics​(DetailAST ast,
                                   int[] line,
                                   int after)
        Process Nested generics.
        Parameters:
        ast - token
        line - unicode code points array of line
        after - position after

      • processSingleGeneric

        private void processSingleGeneric​(DetailAST ast,
                                  int[] line,
                                  int after)
        Process Single-generic.
        Parameters:
        ast - token
        line - unicode code points array of line
        after - position after

      • isGenericBeforeRecordHeader

        private static boolean isGenericBeforeRecordHeader​(DetailAST ast)
        Checks if generic is before record header. Identifies two cases:
        1. In record def, eg: record Session<T>()
        2. In record pattern def, eg: o instanceof Session<String>(var s)
        Parameters:
        ast - ast
        Returns:
        true if generic is before record header

      • isGenericBeforeCtorInvocation

        private static boolean isGenericBeforeCtorInvocation​(DetailAST ast)
        Checks if generic is before constructor invocation. Identifies two cases:
        1. new ArrayList<>();
        2. new Outer.Inner<>();
        Parameters:
        ast - ast
        Returns:
        true if generic is before constructor invocation

      • isGenericAfterNew

        private static boolean isGenericAfterNew​(DetailAST ast)
        Checks if generic is after LITERAL_NEW. Identifies three cases:
        1. new <String>Object();
        2. new <String>Outer.Inner();
        3. new <@A Outer>@B Inner();
        Parameters:
        ast - ast
        Returns:
        true if generic after LITERAL_NEW

      • isGenericBeforeMethod

        private static boolean isGenericBeforeMethod​(DetailAST ast)
        Is generic before method reference.
        Parameters:
        ast - ast
        Returns:
        true if generic before a method ref

      • processStart

        private void processStart​(DetailAST ast)
        Checks the token for the start of Generics.
        Parameters:
        ast - the token to check

      • containsWhitespaceBetween

        private static boolean containsWhitespaceBetween​(int fromIndex,
                                                 int toIndex,
                                                 int... line)
        Returns whether the specified string contains only whitespace between specified indices.
        Parameters:
        fromIndex - the index to start the search from. Inclusive
        toIndex - the index to finish the search. Exclusive
        line - the unicode code points array of line to check
        Returns:
        whether there are only whitespaces (or nothing)

      • containsWhitespaceBefore

        private static boolean containsWhitespaceBefore​(int before,
                                                int... line)
        Returns whether the specified string contains only whitespace up to specified index.
        Parameters:
        before - the index to finish the search. Exclusive
        line - the unicode code points array of line to check
        Returns:
        true if there are only whitespaces, false if there is nothing before or some other characters

      • isCharacterValidAfterGenericEnd

        private static boolean isCharacterValidAfterGenericEnd​(char charAfter)
        Checks whether given character is valid to be right after generic ends.
        Parameters:
        charAfter - character to check
        Returns:
        checks if given character is valid