1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package org.jboss.netty.channel;
17
18 import java.util.concurrent.Executor;
19
20 import org.jboss.netty.channel.group.ChannelGroup;
21 import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory;
22 import org.jboss.netty.util.ExternalResourceReleasable;
23
24
25 /**
26 * The main interface to a transport that creates a {@link Channel} associated
27 * with a certain communication entity such as a network socket. For example,
28 * the {@link NioServerSocketChannelFactory} creates a channel which has a
29 * NIO-based server socket as its underlying communication entity.
30 * <p>
31 * Once a new {@link Channel} is created, the {@link ChannelPipeline} which
32 * was specified as a parameter in the {@link #newChannel(ChannelPipeline)}
33 * is attached to the new {@link Channel}, and starts to handle all associated
34 * {@link ChannelEvent}s.
35 *
36 * <h3>Graceful shutdown</h3>
37 * <p>
38 * To shut down a network application service which is managed by a factory.
39 * you should follow the following steps:
40 * <ol>
41 * <li>close all channels created by the factory and their child channels
42 * usually using {@link ChannelGroup#close()}, and</li>
43 * <li>call {@link #releaseExternalResources()}.</li>
44 * </ol>
45 * <p>
46 * For detailed transport-specific information on shutting down a factory,
47 * please refer to the Javadoc of {@link ChannelFactory}'s subtypes, such as
48 * {@link NioServerSocketChannelFactory}.
49 *
50 * @apiviz.landmark
51 * @apiviz.has org.jboss.netty.channel.Channel oneway - - creates
52 *
53 * @apiviz.exclude ^org\.jboss\.netty\.channel\.([a-z]+\.)+.*ChannelFactory$
54 */
55 public interface ChannelFactory extends ExternalResourceReleasable {
56
57 /**
58 * Creates and opens a new {@link Channel} and attaches the specified
59 * {@link ChannelPipeline} to the new {@link Channel}.
60 *
61 * @param pipeline the {@link ChannelPipeline} which is going to be
62 * attached to the new {@link Channel}
63 *
64 * @return the newly open channel
65 *
66 * @throws ChannelException if failed to create and open a new channel
67 */
68 Channel newChannel(ChannelPipeline pipeline);
69
70 /**
71 * Releases the external resources that this factory depends on to function.
72 * An external resource is a resource that this factory didn't create by
73 * itself. For example, {@link Executor}s that you specified in the factory
74 * constructor are external resources. You can call this method to release
75 * all external resources conveniently when the resources are not used by
76 * this factory or any other part of your application. An unexpected
77 * behavior will be resulted in if the resources are released when there's
78 * an open channel which is managed by this factory.
79 */
80 void releaseExternalResources();
81 }