1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.mina.core.future;
21
22 import org.apache.mina.core.session.IoSession;
23
24 /**
25 * An {@link IoFuture} for {@link IoSession#read() asynchronous read requests}.
26 *
27 * <h3>Example</h3>
28 * <pre>
29 * IoSession session = ...;
30 * // useReadOperation must be enabled to use read operation.
31 * session.getConfig().setUseReadOperation(true);
32 *
33 * ReadFuture future = session.read();
34 * // Wait until a message is received.
35 * future.await();
36 * try {
37 * Object message = future.getMessage();
38 * } catch (Exception e) {
39 * ...
40 * }
41 * </pre>
42 *
43 * @author The Apache MINA Project (dev@mina.apache.org)
44 * @version $Rev: 671827 $, $Date: 2008-06-26 10:49:48 +0200 (jeu, 26 jun 2008) $
45 */
46 public interface ReadFuture extends IoFuture {
47
48 /**
49 * Returns the received message. It returns <tt>null</tt> if this
50 * future is not ready or the associated {@link IoSession} has been closed.
51 *
52 * @throws RuntimeException if read or any relevant operation has failed.
53 */
54 Object getMessage();
55
56 /**
57 * Returns <tt>true</tt> if a message was received successfully.
58 */
59 boolean isRead();
60
61 /**
62 * Returns <tt>true</tt> if the {@link IoSession} associated with this
63 * future has been closed.
64 */
65 boolean isClosed();
66
67 /**
68 * Returns the cause of the read failure if and only if the read
69 * operation has failed due to an {@link Exception}. Otherwise,
70 * <tt>null</tt> is returned.
71 */
72 Throwable getException();
73
74 /**
75 * Sets the message is written, and notifies all threads waiting for
76 * this future. This method is invoked by MINA internally. Please do
77 * not call this method directly.
78 */
79 void setRead(Object message);
80
81 /**
82 * Sets the associated {@link IoSession} is closed. This method is invoked
83 * by MINA internally. Please do not call this method directly.
84 */
85 void setClosed();
86
87 /**
88 * Sets the cause of the read failure, and notifies all threads waiting
89 * for this future. This method is invoked by MINA internally. Please
90 * do not call this method directly.
91 */
92 void setException(Throwable cause);
93
94 ReadFuture await() throws InterruptedException;
95
96 ReadFuture awaitUninterruptibly();
97
98 ReadFuture addListener(IoFutureListener<?> listener);
99
100 ReadFuture removeListener(IoFutureListener<?> listener);
101 }