1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27
28 package org.apache.http.io;
29
30 import java.io.IOException;
31
32 import org.apache.http.util.CharArrayBuffer;
33
34 /**
35 * Session input buffer for blocking connections. This interface is similar to
36 * InputStream class, but it also provides methods for reading lines of text.
37 * <p>
38 * Implementing classes are also expected to manage intermediate data buffering
39 * for optimal input performance.
40 *
41 * @since 4.0
42 */
43 public interface SessionInputBuffer {
44
45 /**
46 * Reads up to {@code len} bytes of data from the session buffer into
47 * an array of bytes. An attempt is made to read as many as
48 * {@code len} bytes, but a smaller number may be read, possibly
49 * zero. The number of bytes actually read is returned as an integer.
50 *
51 * <p> This method blocks until input data is available, end of file is
52 * detected, or an exception is thrown.
53 *
54 * <p> If {@code off} is negative, or {@code len} is negative, or
55 * {@code off+len} is greater than the length of the array
56 * {@code b}, then an {@code IndexOutOfBoundsException} is
57 * thrown.
58 *
59 * @param b the buffer into which the data is read.
60 * @param off the start offset in array {@code b}
61 * at which the data is written.
62 * @param len the maximum number of bytes to read.
63 * @return the total number of bytes read into the buffer, or
64 * {@code -1} if there is no more data because the end of
65 * the stream has been reached.
66 * @throws IOException if an I/O error occurs.
67 */
68 int read(byte[] b, int off, int len) throws IOException;
69
70 /**
71 * Reads some number of bytes from the session buffer and stores them into
72 * the buffer array {@code b}. The number of bytes actually read is
73 * returned as an integer. This method blocks until input data is
74 * available, end of file is detected, or an exception is thrown.
75 *
76 * @param b the buffer into which the data is read.
77 * @return the total number of bytes read into the buffer, or
78 * {@code -1} is there is no more data because the end of
79 * the stream has been reached.
80 * @throws IOException if an I/O error occurs.
81 */
82 int read(byte[] b) throws IOException;
83
84 /**
85 * Reads the next byte of data from this session buffer. The value byte is
86 * returned as an {@code int} in the range {@code 0} to
87 * {@code 255}. If no byte is available because the end of the stream
88 * has been reached, the value {@code -1} is returned. This method
89 * blocks until input data is available, the end of the stream is detected,
90 * or an exception is thrown.
91 *
92 * @return the next byte of data, or {@code -1} if the end of the
93 * stream is reached.
94 * @throws IOException if an I/O error occurs.
95 */
96 int read() throws IOException;
97
98 /**
99 * Reads a complete line of characters up to a line delimiter from this
100 * session buffer into the given line buffer. The number of chars actually
101 * read is returned as an integer. The line delimiter itself is discarded.
102 * If no char is available because the end of the stream has been reached,
103 * the value {@code -1} is returned. This method blocks until input
104 * data is available, end of file is detected, or an exception is thrown.
105 * <p>
106 * The choice of a char encoding and line delimiter sequence is up to the
107 * specific implementations of this interface.
108 *
109 * @param buffer the line buffer.
110 * @return one line of characters
111 * @throws IOException if an I/O error occurs.
112 */
113 int readLine(CharArrayBuffer buffer) throws IOException;
114
115 /**
116 * Reads a complete line of characters up to a line delimiter from this
117 * session buffer. The line delimiter itself is discarded. If no char is
118 * available because the end of the stream has been reached,
119 * {@code null} is returned. This method blocks until input data is
120 * available, end of file is detected, or an exception is thrown.
121 * <p>
122 * The choice of a char encoding and line delimiter sequence is up to the
123 * specific implementations of this interface.
124 *
125 * @return HTTP line as a string
126 * @throws IOException if an I/O error occurs.
127 */
128 String readLine() throws IOException;
129
130 /** Blocks until some data becomes available in the session buffer or the
131 * given timeout period in milliseconds elapses. If the timeout value is
132 * {@code 0} this method blocks indefinitely.
133 *
134 * @param timeout in milliseconds.
135 * @return {@code true} if some data is available in the session
136 * buffer or {@code false} otherwise.
137 * @throws IOException if an I/O error occurs.
138 *
139 * @deprecated (4.3) do not use. This function should be provided at the
140 * connection level
141 */
142 @Deprecated
143 boolean isDataAvailable(int timeout) throws IOException;
144
145 /**
146 * Returns {@link HttpTransportMetrics} for this session buffer.
147 *
148 * @return transport metrics.
149 */
150 HttpTransportMetrics getMetrics();
151
152 }