| /* |
| * 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 org.glassfish.jersey.server; |
| |
| import java.io.IOException; |
| import java.util.Iterator; |
| import java.util.concurrent.ConcurrentLinkedQueue; |
| import java.util.concurrent.CopyOnWriteArrayList; |
| import java.util.logging.Level; |
| import java.util.logging.Logger; |
| |
| import org.glassfish.jersey.server.internal.LocalizationMessages; |
| |
| /** |
| * Used for broadcasting response chunks to multiple {@link ChunkedOutput} instances. |
| * |
| * @param <T> broadcast type. |
| * @author Pavel Bucek |
| * @author Martin Matula |
| */ |
| public class Broadcaster<T> implements BroadcasterListener<T> { |
| // We do not expect large amounts of broadcaster listeners additions/removals, but large amounts of traversals. |
| private final CopyOnWriteArrayList<BroadcasterListener<T>> listeners = |
| new CopyOnWriteArrayList<BroadcasterListener<T>>(); |
| |
| private final ConcurrentLinkedQueue<ChunkedOutput<T>> chunkedOutputs = |
| new ConcurrentLinkedQueue<ChunkedOutput<T>>(); |
| |
| /** |
| * Creates a new instance. |
| * If this constructor is called by a subclass, it assumes the the reason for the subclass to exist is to implement |
| * {@link #onClose(ChunkedOutput)} and {@link #onException(ChunkedOutput, Exception)} methods, so it adds |
| * the newly created instance as the listener. To avoid this, subclasses may call {@link #Broadcaster(Class)} |
| * passing their class as an argument. |
| */ |
| public Broadcaster() { |
| this(Broadcaster.class); |
| } |
| |
| /** |
| * Can be used by subclasses to override the default functionality of adding self to the set of |
| * {@link BroadcasterListener listeners}. If creating a direct instance of a subclass passed in the parameter, |
| * the broadcaster will not register itself as a listener. |
| * |
| * @param subclass subclass of Broadcaster that should not be registered as a listener - if creating a direct instance |
| * of this subclass, this constructor will not register the new instance as a listener. |
| * @see #Broadcaster() |
| */ |
| protected Broadcaster(final Class<? extends Broadcaster> subclass) { |
| if (subclass != getClass()) { |
| listeners.add(this); |
| } |
| } |
| |
| /** |
| * Register {@link ChunkedOutput} to this {@code Broadcaster} instance. |
| * |
| * @param chunkedOutput {@link ChunkedOutput} to register. |
| * @return {@code true} if the instance was successfully registered, {@code false} otherwise. |
| */ |
| public <OUT extends ChunkedOutput<T>> boolean add(final OUT chunkedOutput) { |
| return chunkedOutputs.offer(chunkedOutput); |
| } |
| |
| /** |
| * Un-register {@link ChunkedOutput} from this {@code Broadcaster} instance. |
| * |
| * This method does not close the {@link ChunkedOutput} being unregistered. |
| * |
| * @param chunkedOutput {@link ChunkedOutput} instance to un-register from this broadcaster. |
| * @return {@code true} if the instance was unregistered, {@code false} otherwise. |
| */ |
| public <OUT extends ChunkedOutput<T>> boolean remove(final OUT chunkedOutput) { |
| return chunkedOutputs.remove(chunkedOutput); |
| } |
| |
| /** |
| * Register {@link BroadcasterListener} for {@code Broadcaster} events listening. |
| * <p> |
| * This operation is potentially slow, especially if large number of listeners get registered in the broadcaster. |
| * The {@code Broadcaster} implementation is optimized to efficiently handle small amounts of |
| * concurrent listener registrations and removals and large amounts of registered listener notifications. |
| * </p> |
| * |
| * @param listener listener to be registered. |
| * @return {@code true} if registered, {@code false} otherwise. |
| */ |
| public boolean add(final BroadcasterListener<T> listener) { |
| return listeners.add(listener); |
| } |
| |
| /** |
| * Un-register {@link BroadcasterListener}. |
| * <p> |
| * This operation is potentially slow, especially if large number of listeners get registered in the broadcaster. |
| * The {@code Broadcaster} implementation is optimized to efficiently handle small amounts of |
| * concurrent listener registrations and removals and large amounts of registered listener notifications. |
| * </p> |
| * |
| * @param listener listener to be unregistered. |
| * @return {@code true} if unregistered, {@code false} otherwise. |
| */ |
| public boolean remove(final BroadcasterListener<T> listener) { |
| return listeners.remove(listener); |
| } |
| |
| /** |
| * Broadcast a chunk to all registered {@link ChunkedOutput} instances. |
| * |
| * @param chunk chunk to be sent. |
| */ |
| public void broadcast(final T chunk) { |
| forEachOutput(new Task<ChunkedOutput<T>>() { |
| @Override |
| public void run(final ChunkedOutput<T> cr) throws IOException { |
| cr.write(chunk); |
| } |
| }); |
| } |
| |
| /** |
| * Close all registered {@link ChunkedOutput} instances. |
| */ |
| public void closeAll() { |
| forEachOutput(new Task<ChunkedOutput<T>>() { |
| @Override |
| public void run(final ChunkedOutput<T> cr) throws IOException { |
| cr.close(); |
| } |
| }); |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * Can be implemented by subclasses to handle the event of exception thrown from a particular {@link ChunkedOutput} |
| * instance when trying to write to it or close it. |
| * |
| * @param chunkedOutput instance that threw exception. |
| * @param exception exception that was thrown. |
| */ |
| @Override |
| public void onException(final ChunkedOutput<T> chunkedOutput, final Exception exception) { |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * Can be implemented by subclasses to handle the event of {@link ChunkedOutput} being closed. |
| * |
| * @param chunkedOutput instance that was closed. |
| */ |
| @Override |
| public void onClose(final ChunkedOutput<T> chunkedOutput) { |
| } |
| |
| private static interface Task<T> { |
| void run(T parameter) throws IOException; |
| } |
| |
| private void forEachOutput(final Task<ChunkedOutput<T>> t) { |
| for (Iterator<ChunkedOutput<T>> iterator = chunkedOutputs.iterator(); iterator.hasNext(); ) { |
| ChunkedOutput<T> chunkedOutput = iterator.next(); |
| if (!chunkedOutput.isClosed()) { |
| try { |
| t.run(chunkedOutput); |
| } catch (Exception e) { |
| fireOnException(chunkedOutput, e); |
| } |
| } |
| if (chunkedOutput.isClosed()) { |
| iterator.remove(); |
| fireOnClose(chunkedOutput); |
| } |
| } |
| } |
| |
| private void forEachListener(final Task<BroadcasterListener<T>> t) { |
| for (BroadcasterListener<T> listener : listeners) { |
| try { |
| t.run(listener); |
| } catch (Exception e) { |
| // log, but don't break |
| Logger.getLogger(Broadcaster.class.getName()).log(Level.WARNING, |
| LocalizationMessages.BROADCASTER_LISTENER_EXCEPTION(e.getClass().getSimpleName()), e); |
| } |
| } |
| } |
| |
| private void fireOnException(final ChunkedOutput<T> chunkedOutput, final Exception exception) { |
| forEachListener(new Task<BroadcasterListener<T>>() { |
| @Override |
| public void run(BroadcasterListener<T> parameter) throws IOException { |
| parameter.onException(chunkedOutput, exception); |
| } |
| }); |
| } |
| |
| private void fireOnClose(final ChunkedOutput<T> chunkedOutput) { |
| forEachListener(new Task<BroadcasterListener<T>>() { |
| @Override |
| public void run(BroadcasterListener<T> parameter) throws IOException { |
| parameter.onClose(chunkedOutput); |
| } |
| }); |
| } |
| } |