https://github.com/eclipse-ee4j/jaxrs-api: Jakarta RESTful Web Services (Eclipse Foundation) 
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 * Copyright (c) 2012, 2019 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package jakarta.ws.rs.sse;

import java.util.concurrent.CompletionStage;
import java.util.function.BiConsumer;
import java.util.function.Consumer;


Server-Sent events broadcasting facility.

 Server broadcaster can be used to manage multiple server sinks. It enables sending events to all registered event outputs and provides facility to effectively handle exceptions and closures of individual registered event outputs. 

Instance of this interface is thread safe, meaning that it can be shared and its method invoked from different
threads without causing inconsistent internal state.

Author:Marek Potociar
Since:2.1
/**
 * Server-Sent events broadcasting facility.
 * <p>
 * Server broadcaster can be used to manage multiple {@link SseEventSink server sinks}. It enables sending events to all
 * registered event outputs and provides facility to effectively handle exceptions and closures of individual registered
 * event outputs.
 * <p>
 * Instance of this interface is thread safe, meaning that it can be shared and its method invoked from different
 * threads without causing inconsistent internal state.
 *
 * @author Marek Potociar
 * @since 2.1
 */
public interface SseBroadcaster extends AutoCloseable {

    
Register a listener, which will be called when an exception is thrown by a given SseEventSink when this SseBroadcaster tries to write to it or close it. 
 This operation is potentially slow, especially if large number of listeners get registered in the broadcaster. The SseBroadcaster implementation is optimized to efficiently handle small amounts of concurrent listener registrations and removals and large amounts of registered listener notifications. 
Params:
  • onError – bi-consumer, taking two parameters: SseEventSink, which is the source of the error and the actual Throwable instance.
/**
     * Register a listener, which will be called when an exception is thrown by a given {@link SseEventSink}
     * when this SseBroadcaster tries to write to it or close it.
     * <p>
     * This operation is potentially slow, especially if large number of listeners get registered in the broadcaster. The
     * {@code SseBroadcaster} implementation is optimized to efficiently handle small amounts of concurrent listener
     * registrations and removals and large amounts of registered listener notifications.
     *
     * @param onError bi-consumer, taking two parameters: {@link SseEventSink}, which is the source of the error and the
     * actual {@link Throwable} instance.
     */
    void onError(BiConsumer<SseEventSink, Throwable> onError);

    
Register a listener, which will be called when this SseBroadcaster closes a given event SseEventSink or tries to write to a given SseEventSink that is already closed (either by client closing the connection or by calling SseEventSink.close() on the server side. 
 This operation is potentially slow, especially if large number of listeners get registered in the broadcaster. The SseBroadcaster implementation is optimized to efficiently handle small amounts of concurrent listener registrations and removals and large amounts of registered listener notifications. 
Params:
  • onClose – consumer taking single parameter, a SseEventSink, which was closed.
/**
     * Register a listener, which will be called when this SseBroadcaster closes a given event {@link SseEventSink} or
     * tries to write to a given {@link SseEventSink} that is already closed (either by client closing the connection
     * or by calling {@link SseEventSink#close()} on the server side.
     * <p>
     * This operation is potentially slow, especially if large number of listeners get registered in the broadcaster. The
     * {@code SseBroadcaster} implementation is optimized to efficiently handle small amounts of concurrent listener
     * registrations and removals and large amounts of registered listener notifications.
     *
     * @param onClose consumer taking single parameter, a {@link SseEventSink}, which was closed.
     */
    void onClose(Consumer<SseEventSink> onClose);

    
Register provided SseEventSink instance to this SseBroadcaster. 
Params:
  • sseEventSink – to be registered.
/**
     * Register provided {@link SseEventSink} instance to this {@code SseBroadcaster}.
     *
     * @param sseEventSink to be registered.
     */
    void register(SseEventSink sseEventSink);

    
Publish an SSE event to all registered SseEventSink instances. 
Params:
  • event – SSE event to be published.
Returns:completion stage that completes when the event has been broadcast to all registered event sinks.
/**
     * Publish an SSE event to all registered {@link SseEventSink} instances.
     *
     * @param event SSE event to be published.
     * @return completion stage that completes when the event has been broadcast to all registered event sinks.
     */
    CompletionStage<?> broadcast(final OutboundSseEvent event);

    
Close the broadcaster and all registered SseEventSink instances. 
 Any other resources associated with the SseBroadcaster should be released. 
 Subsequent calls have no effect and are ignored. Once the SseBroadcaster is closed, invoking any other method on the broadcaster instance would result in an IllegalStateException being thrown. 
/**
     * Close the broadcaster and all registered {@link SseEventSink} instances.
     * <p>
     * Any other resources associated with the {@link SseBroadcaster} should be released.
     * <p>
     * Subsequent calls have no effect and are ignored. Once the {@link SseBroadcaster} is closed,
     * invoking any other method on the broadcaster instance would result in an {@link IllegalStateException}
     * being thrown.
     */
    @Override
    void close();
}