1/*
2 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/HttpConnection.java $
3 * $Revision: 548031 $
4 * $Date: 2007-06-17 04:28:38 -0700 (Sun, 17 Jun 2007) $
5 *
6 * ====================================================================
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements.  See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership.  The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with the License.  You may obtain a copy of the License at
14 *
15 *   http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied.  See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 * ====================================================================
24 *
25 * This software consists of voluntary contributions made by many
26 * individuals on behalf of the Apache Software Foundation.  For more
27 * information on the Apache Software Foundation, please see
28 * <http://www.apache.org/>.
29 *
30 */
31
32package org.apache.http;
33
34import java.io.IOException;
35
36/**
37 * A generic HTTP connection, useful on client and server side.
38 *
39 * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
40 *
41 * @version $Revision: 548031 $
42 *
43 * @since 4.0
44 */
45public interface HttpConnection {
46
47    /**
48     * Closes this connection gracefully.
49     * This method will attempt to  flush the transmitter's
50     * internal buffer prior to closing the underlying socket.
51     * This method MUST NOT be called from a different thread to force
52     * shutdown of the connection. Use {@link #shutdown shutdown} instead.
53     */
54    public void close() throws IOException;
55
56    /**
57     * Checks if this connection is open.
58     * @return true if it is open, false if it is closed.
59     */
60    public boolean isOpen();
61
62    /**
63     * Checks whether this connection has gone down.
64     * Network connections may get closed during some time of inactivity
65     * for several reasons. The next time a read is attempted on such a
66     * connection it will throw an IOException.
67     * This method tries to alleviate this inconvenience by trying to
68     * find out if a connection is still usable. Implementations may do
69     * that by attempting a read with a very small timeout. Thus this
70     * method may block for a small amount of time before returning a result.
71     * It is therefore an <i>expensive</i> operation.
72     *
73     * @return  <code>true</code> if attempts to use this connection are
74     *          likely to succeed, or <code>false</code> if they are likely
75     *          to fail and this connection should be closed
76     */
77    public boolean isStale();
78
79    /**
80     * Sets the socket timeout value.
81     *
82     * @param timeout timeout value in milliseconds
83     */
84    void setSocketTimeout(int timeout);
85
86    /**
87     * Returns the socket timeout value.
88     *
89     * @return positive value in milliseconds if a timeout is set,
90     * <code>0</code> if timeout is disabled or <code>-1</code> if
91     * timeout is undefined.
92     */
93    int getSocketTimeout();
94
95    /**
96     * Force-closes this connection.
97     * This is the only method of a connection which may be called
98     * from a different thread to terminate the connection.
99     * This method will not attempt to flush the transmitter's
100     * internal buffer prior to closing the underlying socket.
101     */
102    public void shutdown() throws IOException;
103
104    /**
105     * Returns a collection of connection metrcis
106     * @return HttpConnectionMetrics
107     */
108    HttpConnectionMetrics getMetrics();
109
110}
111