Package org.osgi.util.pushstream

Class PushEvent<T>

java.lang.Object
org.osgi.util.pushstream.PushEvent<T>
Type Parameters:
T - The payload type of the event.
@ProviderType public abstract class PushEvent<T> extends Object
A PushEvent is an immutable object that is transferred through a communication channel to push information to a downstream consumer. The event has three different types:
  • PushEvent.EventType.DATA – Provides access to a typed data element in the stream.
  • PushEvent.EventType.CLOSE – The stream is closed. After receiving this event, no more events will follow.
  • PushEvent.EventType.ERROR – The stream ran into an unrecoverable problem and is sending the reason downstream. The stream is closed and no more events will follow after this event.
"Immutable"

  • Method Details

    • getType

      public abstract PushEvent.EventType getType()
      Get the type of this event.
      Returns:
      The type of this event.

    • getData

      public T getData()
      Return the data for this event.
      Returns:
      The data payload.
      Throws:
      IllegalStateException - if this event is not a PushEvent.EventType.DATA event.

    • getFailure

      public Throwable getFailure()
      Return the error that terminated the stream.
      Returns:
      The error that terminated the stream.
      Throws:
      IllegalStateException - if this event is not an PushEvent.EventType.ERROR event.

    • isTerminal

      public boolean isTerminal()
      Answer if no more events will follow after this event.
      Returns:
      false if this is a data event, otherwise true.

    • data

      public static <T> PushEvent<T> data(T payload)
      Create a new data event.
      Type Parameters:
      T - The payload type.
      Parameters:
      payload - The payload.
      Returns:
      A new data event wrapping the specified payload.

    • error

      public static <T> PushEvent<T> error(Throwable t)
      Create a new error event.
      Type Parameters:
      T - The payload type.
      Parameters:
      t - The error.
      Returns:
      A new error event with the specified error.

    • close

      public static <T> PushEvent<T> close()
      Create a new close event.
      Type Parameters:
      T - The payload type.
      Returns:
      A new close event.

    • nodata

      public <X> PushEvent<X> nodata()
      Convenience to cast a close/error event to another payload type. Since the payload type is not needed for these events this is harmless. This therefore allows you to forward the close/error event downstream without creating anew event.
      Type Parameters:
      X - The new payload type.
      Returns:
      The current error or close event mapped to a new payload type.
      Throws:
      IllegalStateException - if the event is a PushEvent.EventType.DATA event.