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 */
45 public interface ReadFuture extends IoFuture {
46
47 /**
48 * Returns the received message. It returns <tt>null</tt> if this
49 * future is not ready or the associated {@link IoSession} has been closed.
50 *
51 * @throws RuntimeException if read or any relevant operation has failed.
52 */
53 Object getMessage();
54
55 /**
56 * Returns <tt>true</tt> if a message was received successfully.
57 */
58 boolean isRead();
59
60 /**
61 * Returns <tt>true</tt> if the {@link IoSession} associated with this
62 * future has been closed.
63 */
64 boolean isClosed();
65
66 /**
67 * Returns the cause of the read failure if and only if the read
68 * operation has failed due to an {@link Exception}. Otherwise,
69 * <tt>null</tt> is returned.
70 */
71 Throwable getException();
72
73 /**
74 * Sets the message is written, and notifies all threads waiting for
75 * this future. This method is invoked by MINA internally. Please do
76 * not call this method directly.
77 */
78 void setRead(Object message);
79
80 /**
81 * Sets the associated {@link IoSession} is closed. This method is invoked
82 * by MINA internally. Please do not call this method directly.
83 */
84 void setClosed();
85
86 /**
87 * Sets the cause of the read failure, and notifies all threads waiting
88 * for this future. This method is invoked by MINA internally. Please
89 * do not call this method directly.
90 */
91 void setException(Throwable cause);
92
93 ReadFuture await() throws InterruptedException;
94
95 ReadFuture awaitUninterruptibly();
96
97 ReadFuture addListener(IoFutureListener<?> listener);
98
99 ReadFuture removeListener(IoFutureListener<?> listener);
100 }