Package com.puppycrawl.tools.checkstyle.checks.annotation

Class AnnotationUseStyleCheck

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

    Checks the style of elements in annotations.

    Annotations have three element styles starting with the least verbose.

    • ElementStyleOption.COMPACT_NO_ARRAY
    • ElementStyleOption.COMPACT
    • ElementStyleOption.EXPANDED

    To not enforce an element style a ElementStyleOption.IGNORE type is provided. The desired style can be set through the elementStyle property.

    Using the ElementStyleOption.EXPANDED style is more verbose. The expanded version is sometimes referred to as "named parameters" in other languages.

    Using the ElementStyleOption.COMPACT style is less verbose. This style can only be used when there is an element called 'value' which is either the sole element or all other elements have default values.

    Using the ElementStyleOption.COMPACT_NO_ARRAY style is less verbose. It is similar to the ElementStyleOption.COMPACT style but single value arrays are flagged. With annotations a single value array does not need to be placed in an array initializer.

    The ending parenthesis are optional when using annotations with no elements. To always require ending parenthesis use the ClosingParensOption.ALWAYS type. To never have ending parenthesis use the ClosingParensOption.NEVER type. To not enforce a closing parenthesis preference a ClosingParensOption.IGNORE type is provided. Set this through the closingParens property.

    Annotations also allow you to specify arrays of elements in a standard format. As with normal arrays, a trailing comma is optional. To always require a trailing comma use the TrailingArrayCommaOption.ALWAYS type. To never have a trailing comma use the TrailingArrayCommaOption.NEVER type. To not enforce a trailing array comma preference a TrailingArrayCommaOption.IGNORE type is provided. Set this through the trailingArrayComma property.

    By default the ElementStyleOption is set to COMPACT_NO_ARRAY, the TrailingArrayCommaOption is set to NEVER, and the ClosingParensOption is set to NEVER.

    According to the JLS, it is legal to include a trailing comma in arrays used in annotations but Sun's Java 5 & 6 compilers will not compile with this syntax. This may in be a bug in Sun's compilers since eclipse 3.4's built-in compiler does allow this syntax as defined in the JLS. Note: this was tested with compilers included with JDK versions 1.5.0.17 and 1.6.0.11 and the compiler included with eclipse 3.4.1.

    See Java Language specification, §9.7.

    • Property elementStyle - Define the annotation element styles. Type is com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationUseStyleCheck$ElementStyleOption. Default value is compact_no_array.
    • Property closingParens - Define the policy for ending parenthesis. Type is com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationUseStyleCheck$ClosingParensOption. Default value is never.
    • Property trailingArrayComma - Define the policy for trailing comma in arrays. Type is com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationUseStyleCheck$TrailingArrayCommaOption. Default value is never.

    To configure the check: 

     <module name="AnnotationUseStyle"/>

    To configure the check to enforce an expanded style, with a trailing array comma set to never and always including the closing parenthesis. 

     <module name="AnnotationUseStyle">
   <property name="elementStyle" value="expanded"/>
   <property name="trailingArrayComma" value="never"/>
   <property name="closingParens" value="always"/>
 </module>

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • annotation.incorrect.style
    • annotation.parens.missing
    • annotation.parens.present
    • annotation.trailing.comma.missing
    • annotation.trailing.comma.present
    Since:
    5.0

    • Field Detail

      • MSG_KEY_ANNOTATION_INCORRECT_STYLE

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

      • MSG_KEY_ANNOTATION_PARENS_MISSING

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

      • MSG_KEY_ANNOTATION_PARENS_PRESENT

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

      • MSG_KEY_ANNOTATION_TRAILING_COMMA_MISSING

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

      • MSG_KEY_ANNOTATION_TRAILING_COMMA_PRESENT

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

    • Constructor Detail

      • AnnotationUseStyleCheck

        public AnnotationUseStyleCheck()

    • Method Detail

      • setElementStyle

        public void setElementStyle​(java.lang.String style)
        Setter to define the annotation element styles.
        Parameters:
        style - string representation

      • setTrailingArrayComma

        public void setTrailingArrayComma​(java.lang.String comma)
        Setter to define the policy for trailing comma in arrays.
        Parameters:
        comma - string representation

      • setClosingParens

        public void setClosingParens​(java.lang.String parens)
        Setter to define the policy for ending parenthesis.
        Parameters:
        parens - string representation

      • 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