/*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.ogt.http.io;
import java.io.IOException;
import org.apache.ogt.http.util.CharArrayBuffer;
/**
* Session input buffer for blocking connections. This interface is similar to
* InputStream class, but it also provides methods for reading lines of text.
* <p>
* Implementing classes are also expected to manage intermediate data buffering
* for optimal input performance.
*
* @since 4.0
*/
public interface SessionInputBuffer {
/**
* Reads up to <code>len</code> bytes of data from the session buffer into
* an array of bytes. An attempt is made to read as many as
* <code>len</code> bytes, but a smaller number may be read, possibly
* zero. The number of bytes actually read is returned as an integer.
*
* <p> This method blocks until input data is available, end of file is
* detected, or an exception is thrown.
*
* <p> If <code>off</code> is negative, or <code>len</code> is negative, or
* <code>off+len</code> is greater than the length of the array
* <code>b</code>, then an <code>IndexOutOfBoundsException</code> is
* thrown.
*
* @param b the buffer into which the data is read.
* @param off the start offset in array <code>b</code>
* at which the data is written.
* @param len the maximum number of bytes to read.
* @return the total number of bytes read into the buffer, or
* <code>-1</code> if there is no more data because the end of
* the stream has been reached.
* @exception IOException if an I/O error occurs.
*/
int read(byte[] b, int off, int len) throws IOException;
/**
* Reads some number of bytes from the session buffer and stores them into
* the buffer array <code>b</code>. The number of bytes actually read is
* returned as an integer. This method blocks until input data is
* available, end of file is detected, or an exception is thrown.
*
* @param b the buffer into which the data is read.
* @return the total number of bytes read into the buffer, or
* <code>-1</code> is there is no more data because the end of
* the stream has been reached.
* @exception IOException if an I/O error occurs.
*/
int read(byte[] b) throws IOException;
/**
* Reads the next byte of data from this session buffer. The value byte is
* returned as an <code>int</code> in the range <code>0</code> to
* <code>255</code>. If no byte is available because the end of the stream
* has been reached, the value <code>-1</code> is returned. This method
* blocks until input data is available, the end of the stream is detected,
* or an exception is thrown.
*
* @return the next byte of data, or <code>-1</code> if the end of the
* stream is reached.
* @exception IOException if an I/O error occurs.
*/
int read() throws IOException;
/**
* Reads a complete line of characters up to a line delimiter from this
* session buffer into the given line buffer. The number of chars actually
* read is returned as an integer. The line delimiter itself is discarded.
* If no char is available because the end of the stream has been reached,
* the value <code>-1</code> is returned. This method blocks until input
* data is available, end of file is detected, or an exception is thrown.
* <p>
* The choice of a char encoding and line delimiter sequence is up to the
* specific implementations of this interface.
*
* @param buffer the line buffer.
* @return one line of characters
* @exception IOException if an I/O error occurs.
*/
int readLine(CharArrayBuffer buffer) throws IOException;
/**
* Reads a complete line of characters up to a line delimiter from this
* session buffer. The line delimiter itself is discarded. If no char is
* available because the end of the stream has been reached,
* <code>null</code> is returned. This method blocks until input data is
* available, end of file is detected, or an exception is thrown.
* <p>
* The choice of a char encoding and line delimiter sequence is up to the
* specific implementations of this interface.
*
* @return HTTP line as a string
* @exception IOException if an I/O error occurs.
*/
String readLine() throws IOException;
/** Blocks until some data becomes available in the session buffer or the
* given timeout period in milliseconds elapses. If the timeout value is
* <code>0</code> this method blocks indefinitely.
*
* @param timeout in milliseconds.
* @return <code>true</code> if some data is available in the session
* buffer or <code>false</code> otherwise.
* @exception IOException if an I/O error occurs.
*/
boolean isDataAvailable(int timeout) throws IOException;
/**
* Returns {@link HttpTransportMetrics} for this session buffer.
*
* @return transport metrics.
*/
HttpTransportMetrics getMetrics();
}