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

Class AnnotationLocationCheck

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

    Checks location of annotation on language elements. By default, Check enforce to locate annotations immediately after documentation block and before target element, annotation should be located on separate line from target element. This check also verifies that the annotations are on the same indenting level as the annotated element if they are not on the same line.

    Attention: Elements that cannot have JavaDoc comments like local variables are not in the scope of this check even though a token type like VARIABLE_DEF would match them.

    Attention: Annotations among modifiers are ignored (looks like false-negative) as there might be a problem with annotations for return types: 

     public @Nullable Long getStartTimeOrNull() { ... }

    Such annotations are better to keep close to type. Due to limitations, Checkstyle can not examine the target of an annotation.

    Example: 

     @Override
 @Nullable
 public String getNameIfPresent() { ... }
    • Property allowSamelineMultipleAnnotations - Allow annotation(s) to be located on the same line as target element. Type is boolean. Default value is false.
    • Property allowSamelineSingleParameterlessAnnotation - Allow single parameterless annotation to be located on the same line as target element. Type is boolean. Default value is true.
    • Property allowSamelineParameterizedAnnotation - Allow one and only parameterized annotation to be located on the same line as target element. Type is boolean. Default value is false.
    • Property tokens - tokens to check Type is java.lang.String[]. Validation type is tokenSet. Default value is: CLASS_DEF, INTERFACE_DEF, PACKAGE_DEF, ENUM_CONSTANT_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF, VARIABLE_DEF, RECORD_DEF, COMPACT_CTOR_DEF.

    To configure the default check to allow one single parameterless annotation on the same line: 

     <module name="AnnotationLocation"/>

    Example for above configuration: 

     @NotNull private boolean field1; //ok
 @Override public int hashCode() { return 1; } //ok
 @NotNull //ok
 private boolean field2;
 @Override //ok
 public boolean equals(Object obj) { return true; }
 @Mock DataLoader loader; //ok
 @SuppressWarnings("deprecation") DataLoader loader; //violation
 @SuppressWarnings("deprecation") public int foo() { return 1; } //violation
 @NotNull @Mock DataLoader loader; //violation

    Use the following configuration to allow multiple annotations on the same line: 

     <module name="AnnotationLocation">
   <property name="allowSamelineMultipleAnnotations" value="true"/>
   <property name="allowSamelineSingleParameterlessAnnotation"
     value="false"/>
   <property name="allowSamelineParameterizedAnnotation" value="false"/>
 </module>

    Example to allow any location multiple annotations: 

     @NotNull private boolean field1; //ok
 @Override public int hashCode() { return 1; } //ok
 @NotNull //ok
 private boolean field2;
 @Override //ok
 public boolean equals(Object obj) { return true; }
 @Mock DataLoader loader; //ok
 @SuppressWarnings("deprecation") DataLoader loader; //ok
 @SuppressWarnings("deprecation") public int foo() { return 1; } //ok
 @NotNull @Mock DataLoader loader; //ok

    Use the following configuration to allow only one and only parameterized annotation on the same line: 

     <module name="AnnotationLocation">
   <property name="allowSamelineMultipleAnnotations" value="false"/>
   <property name="allowSamelineSingleParameterlessAnnotation"
     value="false"/>
   <property name="allowSamelineParameterizedAnnotation" value="true"/>
 </module>

    Example to allow only one and only parameterized annotation on the same line: 

     @NotNull private boolean field1; //violation
 @Override public int hashCode() { return 1; } //violation
 @NotNull //ok
 private boolean field2;
 @Override //ok
 public boolean equals(Object obj) { return true; }
 @Mock DataLoader loader; //violation
 @SuppressWarnings("deprecation") DataLoader loader; //ok
 @SuppressWarnings("deprecation") public int foo() { return 1; } //ok
 @NotNull @Mock DataLoader loader; //violation

    Use the following configuration to only validate annotations on methods to allow one single parameterless annotation on the same line: 

     <module name="AnnotationLocation">
   <property name="tokens" value="METHOD_DEF"/>
   <property name="allowSamelineMultipleAnnotations" value="false"/>
   <property name="allowSamelineSingleParameterlessAnnotation"
     value="true"/>
   <property name="allowSamelineParameterizedAnnotation" value="false"/>
  </module>

    Example for above configuration to check only methods: 

     @NotNull private boolean field1; //ok
 @Override public int hashCode() { return 1; } //ok
 @NotNull //ok
 private boolean field2;
 @Override //ok
 public boolean equals(Object obj) { return true; }
 @Mock DataLoader loader; //ok
 @SuppressWarnings("deprecation") DataLoader loader; //ok
 @SuppressWarnings("deprecation") public int foo() { return 1; } //violation
 @NotNull @Mock DataLoader loader; //ok

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • annotation.location
    • annotation.location.alone
    Since:
    6.0

    • Field Detail

      • MSG_KEY_ANNOTATION_LOCATION_ALONE

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

      • MSG_KEY_ANNOTATION_LOCATION

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

    • Constructor Detail

      • AnnotationLocationCheck

        public AnnotationLocationCheck()

    • Method Detail

      • setAllowSamelineSingleParameterlessAnnotation

        public final void setAllowSamelineSingleParameterlessAnnotation​(boolean allow)
        Setter to allow single parameterless annotation to be located on the same line as target element.
        Parameters:
        allow - User's value of allowSamelineSingleParameterlessAnnotation.

      • setAllowSamelineParameterizedAnnotation

        public final void setAllowSamelineParameterizedAnnotation​(boolean allow)
        Setter to allow one and only parameterized annotation to be located on the same line as target element.
        Parameters:
        allow - User's value of allowSamelineParameterizedAnnotation.

      • setAllowSamelineMultipleAnnotations

        public final void setAllowSamelineMultipleAnnotations​(boolean allow)
        Setter to allow annotation(s) to be located on the same line as target element.
        Parameters:
        allow - User's value of allowSamelineMultipleAnnotations.

      • 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