Module jdk.jfr

Package jdk.jfr

Annotation Type MetadataDefinition

@Retention(RUNTIME)
@Target(TYPE)
public @interface MetadataDefinition

Meta annotation for defining new types of event metadata.

Example, a transaction event with two user-defined annotations, @Severity and @TransactionId

 
@MetadataDefinition
@Label("Severity")
@Description("Value between 0 and 100 that indicates severity. 100 is most severe.")
@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.TYPE })
 public @interface @Severity {
   int value() default 50;
 }

@MetadataDefinition
@Label("Transaction Id")
@Relational
@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.FIELD })
 public @interface @Severity {
 }

@Severity(80)
@Label("Transaction Blocked");
 class TransactionBlocked extends Event {
  @TransactionId
  @Label("Transaction");
   long transactionId;

  @TransactionId
  @Label("Transaction Blocker");
   long transactionId;
 }

 
 

Adding @MetadataDefinition to the declaration of @Severity and @TransactionId ensures the information is saved by Flight Recorder.

Since:

9