Class AnnotationElement

java.lang.Object
jdk.jfr.AnnotationElement
public final class AnnotationElement extends Object
Describes event metadata, such as labels, descriptions and units.

The following example shows how AnnotationElement can be used to dynamically define events. 

List<AnnotationElement> typeAnnotations = new ArrayList<>();
typeAnnotations.add(new AnnotationElement(Name.class, "com.example.HelloWorld"));
typeAnnotations.add(new AnnotationElement(Label.class, "Hello World"));
typeAnnotations.add(new AnnotationElement(Description.class, "Helps programmer getting started"));

List<AnnotationElement> fieldAnnotations = new ArrayList<>();
fieldAnnotations.add(new AnnotationElement(Label.class, "Message"));

List<ValueDescriptor> fields = new ArrayList<>();
fields.add(new ValueDescriptor(String.class, "message", fieldAnnotations));

EventFactory f = EventFactory.create(typeAnnotations, fields);
Event event = f.newEvent();
event.commit();
Since:
9

  • Constructor Summary

    Constructors
    Constructor
    Description
    AnnotationElement(Class<? extends Annotation> annotationType)
    Creates an annotation element to use for dynamically defined events.
    AnnotationElement(Class<? extends Annotation> annotationType, Object value)
    Creates an annotation element to use for dynamically defined events.
    AnnotationElement(Class<? extends Annotation> annotationType, Map<String,Object> values)
    Creates an annotation element to use for dynamically defined events.

  • Method Summary

    Modifier and Type
    Method
    Description
    final <A> A
    getAnnotation(Class<? extends Annotation> annotationType)
    Returns the first annotation for the specified type if an AnnotationElement with the same name exists, else null.
    List<AnnotationElement>
    getAnnotationElements()
    Returns an immutable list of annotation elements for this AnnotationElement.
    long
    getTypeId()
    Returns the type ID for this AnnotationElement.
    String
    getTypeName()
    Returns the fully qualified name of the annotation type that corresponds to this AnnotationElement (for example, "jdk.jfr.Label").
    Object
    getValue(String name)
    Returns a value for this AnnotationElement.
    List<ValueDescriptor>
    getValueDescriptors()
    Returns an immutable list of descriptors that describes the annotation values for this AnnotationElement.
    List<Object>
    getValues()
    Returns an immutable list of annotation values in an order that matches the value descriptors for this AnnotationElement.
    boolean
    hasValue(String name)
    Returns true if an annotation value with the specified name exists in this AnnotationElement.

    Methods declared in class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    Modifier and Type
    Method
    Description
    protected Object
    clone()
    Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
    boolean
    equals(Object o)
    Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
    protected void
    finalize()
    Deprecated, for removal: This API element is subject to removal in a future version.
    May cause performance issues, deadlocks and hangs.
    final Class<? extends Object>
    getClass()
    Answers the unique instance of java.lang.Class which represents the class of the receiver.
    int
    hashCode()
    Answers an integer hash code for the receiver.
    final void
    notify()
    Causes one thread which is waiting on the receiver to be made ready to run.
    final void
    notifyAll()
    Causes all threads which are waiting on the receiver to be made ready to run.
    String
    toString()
    Answers a string containing a concise, human-readable description of the receiver.
    final void
    wait()
    Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
    final void
    wait(long time)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
    final void
    wait(long time, int frac)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

  • Constructor Details

    • AnnotationElement

      public AnnotationElement(Class<? extends Annotation> annotationType, Map<String,Object> values)
      Creates an annotation element to use for dynamically defined events.

      Supported value types are byte, int, short, long, double, float, boolean, char, and String. Enums, arrays and classes, are not supported.

      If annotationType has annotations (directly present, indirectly present, or associated), then those annotation are recursively included. However, both the annotationType and any annotation found recursively must have the MetadataDefinition annotation.

      To statically define events, see Event class.

      Parameters:
      annotationType - interface extending java.lang.annotation.Annotation, not null
      values - a Map with keys that match method names of the specified annotation interface
      Throws:
      IllegalArgumentException - if value/key is null, an unsupported value type is used, or a value/key is used that doesn't match the signatures in the annotationType

    • AnnotationElement

      public AnnotationElement(Class<? extends Annotation> annotationType, Object value)
      Creates an annotation element to use for dynamically defined events.

      Supported value types are byte, int, short, long, double, float, boolean, char, and String. Enums, arrays, and classes are not supported.

      If annotationType has annotations (directly present, indirectly present, or associated), then those annotations are recursively included. However, both annotationType and any annotation found recursively must have the MetadataDefinition annotation.

      To statically define events, see Event class.

      Parameters:
      annotationType - interface extending java.lang.annotation.Annotation, not null
      value - the value that matches the value method of the specified annotationType
      Throws:
      IllegalArgumentException - if value/key is null, an unsupported value type is used, or a value/key is used that doesn't match the signatures in the annotationType

    • AnnotationElement

      public AnnotationElement(Class<? extends Annotation> annotationType)
      Creates an annotation element to use for dynamically defined events.

      Supported value types are byte, short, int, long, double, float, boolean, char, and String. Enums, arrays, and classes are not supported.

      If annotationType has annotations (directly present, indirectly present or associated), then those annotation are recursively included. However, both annotationType and any annotation found recursively must have the MetadataDefinition annotation.

      To statically define events, see Event class.

      Parameters:
      annotationType - interface extending java.lang.annotation.Annotation, not null

  • Method Details

    • getValues

      public List<Object> getValues()
      Returns an immutable list of annotation values in an order that matches the value descriptors for this AnnotationElement.
      Returns:
      list of values, not null

    • getValueDescriptors

      public List<ValueDescriptor> getValueDescriptors()
      Returns an immutable list of descriptors that describes the annotation values for this AnnotationElement.
      Returns:
      the list of value descriptors for this Annotation, not null

    • getAnnotationElements

      public List<AnnotationElement> getAnnotationElements()
      Returns an immutable list of annotation elements for this AnnotationElement.
      Returns:
      a list of meta annotation, not null

    • getTypeName

      public String getTypeName()
      Returns the fully qualified name of the annotation type that corresponds to this AnnotationElement (for example, "jdk.jfr.Label").
      Returns:
      type name, not null

    • getValue

      public Object getValue(String name)
      Returns a value for this AnnotationElement.
      Parameters:
      name - the name of the method in the annotation interface, not null.
      Returns:
      the annotation value, not null.
      Throws:
      IllegalArgumentException - if a method with the specified name does not exist in the annotation

    • hasValue

      public boolean hasValue(String name)
      Returns true if an annotation value with the specified name exists in this AnnotationElement.
      Parameters:
      name - name of the method in the annotation interface to find, not null
      Returns:
      true if method exists, false otherwise

    • getAnnotation

      public final <A> A getAnnotation(Class<? extends Annotation> annotationType)
      Returns the first annotation for the specified type if an AnnotationElement with the same name exists, else null.
      Type Parameters:
      A - the type of the annotation to query for and return if it exists
      Parameters:
      annotationType - the Class object corresponding to the annotation type, not null
      Returns:
      this element's annotation for the specified annotation type if it exists, else null

    • getTypeId

      public long getTypeId()
      Returns the type ID for this AnnotationElement.

      The ID is a unique identifier for the type in the Java Virtual Machine (JVM). The ID might not be the same between JVM instances.

      Returns:
      the type ID, not negative