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 Details

    • MSG_KEY_ANNOTATION_LOCATION_ALONE

      public static final String MSG_KEY_ANNOTATION_LOCATION_ALONE
      A key is pointing to the warning message text in "messages.properties" file.
      See Also:
    • MSG_KEY_ANNOTATION_LOCATION

      public static final String MSG_KEY_ANNOTATION_LOCATION
      A key is pointing to the warning message text in "messages.properties" file.
      See Also:
  • Constructor Details

    • AnnotationLocationCheck

      public AnnotationLocationCheck()
  • Method Details

    • 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:
    • 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:
    • 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:
    • visitToken

      public void visitToken(DetailAST ast)
      Description copied from class: AbstractCheck
      Called to process a token.
      Overrides:
      visitToken in class AbstractCheck
      Parameters:
      ast - the token to process