001/* 002 * ==================================================================== 003 * Licensed to the Apache Software Foundation (ASF) under one 004 * or more contributor license agreements. See the NOTICE file 005 * distributed with this work for additional information 006 * regarding copyright ownership. The ASF licenses this file 007 * to you under the Apache License, Version 2.0 (the 008 * "License"); you may not use this file except in compliance 009 * with the License. You may obtain a copy of the License at 010 * 011 * http://www.apache.org/licenses/LICENSE-2.0 012 * 013 * Unless required by applicable law or agreed to in writing, 014 * software distributed under the License is distributed on an 015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 016 * KIND, either express or implied. See the License for the 017 * specific language governing permissions and limitations 018 * under the License. 019 * ==================================================================== 020 * 021 * This software consists of voluntary contributions made by many 022 * individuals on behalf of the Apache Software Foundation. For more 023 * information on the Apache Software Foundation, please see 024 * <http://www.apache.org/>. 025 * 026 */ 027 028package org.apache.http.io; 029 030import java.io.IOException; 031 032import org.apache.http.util.CharArrayBuffer; 033 034/** 035 * Session input buffer for blocking connections. This interface is similar to 036 * InputStream class, but it also provides methods for reading lines of text. 037 * <p> 038 * Implementing classes are also expected to manage intermediate data buffering 039 * for optimal input performance. 040 * 041 * @since 4.0 042 */ 043public interface SessionInputBuffer { 044 045 /** 046 * Reads up to {@code len} bytes of data from the session buffer into 047 * an array of bytes. An attempt is made to read as many as 048 * {@code len} bytes, but a smaller number may be read, possibly 049 * zero. The number of bytes actually read is returned as an integer. 050 * 051 * <p> This method blocks until input data is available, end of file is 052 * detected, or an exception is thrown. 053 * 054 * <p> If {@code off} is negative, or {@code len} is negative, or 055 * {@code off+len} is greater than the length of the array 056 * {@code b}, then an {@code IndexOutOfBoundsException} is 057 * thrown. 058 * 059 * @param b the buffer into which the data is read. 060 * @param off the start offset in array {@code b} 061 * at which the data is written. 062 * @param len the maximum number of bytes to read. 063 * @return the total number of bytes read into the buffer, or 064 * {@code -1} if there is no more data because the end of 065 * the stream has been reached. 066 * @throws IOException if an I/O error occurs. 067 */ 068 int read(byte[] b, int off, int len) throws IOException; 069 070 /** 071 * Reads some number of bytes from the session buffer and stores them into 072 * the buffer array {@code b}. The number of bytes actually read is 073 * returned as an integer. This method blocks until input data is 074 * available, end of file is detected, or an exception is thrown. 075 * 076 * @param b the buffer into which the data is read. 077 * @return the total number of bytes read into the buffer, or 078 * {@code -1} is there is no more data because the end of 079 * the stream has been reached. 080 * @throws IOException if an I/O error occurs. 081 */ 082 int read(byte[] b) throws IOException; 083 084 /** 085 * Reads the next byte of data from this session buffer. The value byte is 086 * returned as an {@code int} in the range {@code 0} to 087 * {@code 255}. If no byte is available because the end of the stream 088 * has been reached, the value {@code -1} is returned. This method 089 * blocks until input data is available, the end of the stream is detected, 090 * or an exception is thrown. 091 * 092 * @return the next byte of data, or {@code -1} if the end of the 093 * stream is reached. 094 * @throws IOException if an I/O error occurs. 095 */ 096 int read() throws IOException; 097 098 /** 099 * 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}