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 java.lang.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.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	PushEvent.EventType	The type of a PushEvent.

Method Summary

Modifier and Type	Method	Description
static <T> PushEvent<T>	close()	Create a new close event.
static <T> PushEvent<T>	data(T payload)	Create a new data event.
static <T> PushEvent<T>	error(java.lang.Throwable t)	Create a new error event.
T	getData()	Return the data for this event.
java.lang.Throwable	getFailure()	Return the error that terminated the stream.
abstract PushEvent.EventType	getType()	Get the type of this event.
boolean	isTerminal()	Answer if no more events will follow after this event.
<X> PushEvent<X>	nodata()	Convenience to cast a close/error event to another payload type.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

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:

java.lang.IllegalStateException - if this event is not a PushEvent.EventType.DATA event.

getFailure

public java.lang.Throwable getFailure()

Return the error that terminated the stream.

Returns:

The error that terminated the stream.

Throws:

java.lang.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(java.lang.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:

java.lang.IllegalStateException - if the event is a PushEvent.EventType.DATA event.