/*
* ChunkedProducer.java February 2007
*
* Copyright (C) 2001, Niall Gallagher <niallg@users.sf.net>
*
* Licensed 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.
*/
package org.simpleframework.http.core;
import java.io.IOException;
import java.nio.ByteBuffer;
import org.simpleframework.transport.Sender;
/**
* The <code>ChunkedProducer</code> object is used to encode data in the chunked
* encoding format. A chunked producer is required when the length of the
* emitted content is unknown. It enables the HTTP pipeline to remain open as it
* is a self delimiting format. This is preferred over the
* <code>CloseProducer</code> for HTTP/1.1 as it maintains the pipeline and thus
* the cost of creating it.
*
* @author Niall Gallagher
*
* @see org.simpleframework.http.message.ChunkedConsumer
*/
class ChunkedProducer implements Producer {
/**
* This is the size line which is used to generate the size.
*/
private byte[] size = { '0', '0', '0', '0', '0', '0', '0', '0', '\r', '\n' };
/**
* This is the hexadecimal alphabet used to translate the size.
*/
private byte[] index = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f' };
/**
* This is the zero length chunk sent when this is completed.
*/
private byte[] zero = { '0', '\r', '\n', '\r', '\n' };
/**
* This is the monitor used to notify the initiator of events.
*/
private Monitor monitor;
/**
* This is the underlying sender used to deliver the encoded data.
*/
private Sender sender;
/**
* Constructor for the <code>ChunkedProducer</code> object. This is used to
* create a producer that can sent data in the chunked encoding format. Once
* the data is encoded in the format it is handed to the provided
* <code>Sender</code> object which will then deliver it to the client using
* the underlying transport.
*
* @param sender
* this is the sender used to deliver the content
* @param monitor
* this is the monitor used to signal I/O events
*/
public ChunkedProducer(Sender sender, Monitor monitor) {
this.monitor = monitor;
this.sender = sender;
}
/**
* This method is used to encode the provided array of bytes in a HTTP/1.1
* complaint format and sent it to the client. Once the data has been
* encoded it is handed to the transport layer within the server, which may
* choose to buffer the data if the content is too small to send efficiently
* or if the socket is not write ready.
*
* @param array
* this is the array of bytes to send to the client
*/
@Override
public void produce(byte[] array) throws IOException {
this.produce(array, 0, array.length);
}
/**
* This method is used to encode the provided array of bytes in a HTTP/1.1
* complaint format and sent it to the client. Once the data has been
* encoded it is handed to the transport layer within the server, which may
* choose to buffer the data if the content is too small to send efficiently
* or if the socket is not write ready.
*
* @param array
* this is the array of bytes to send to the client
* @param off
* this is the offset within the array to send from
* @param len
* this is the number of bytes that are to be sent
*/
@Override
public void produce(byte[] array, int off, int len) throws IOException {
ByteBuffer buffer = ByteBuffer.wrap(array, off, len);
if (len > 0) {
this.produce(buffer);
}
}
/**
* This method is used to encode the provided buffer of bytes in a HTTP/1.1
* compliant format and sent it to the client. Once the data has been
* encoded it is handed to the transport layer within the server, which may
* choose to buffer the data if the content is too small to send efficiently
* or if the socket is not write ready.
*
* @param buffer
* this is the buffer of bytes to send to the client
*/
@Override
public void produce(ByteBuffer buffer) throws IOException {
int mark = buffer.position();
int size = buffer.limit();
if (mark > size)
throw new ProducerException("Buffer position greater than limit");
this.produce(buffer, 0, size - mark);
}
/**
* This method is used to encode the provided buffer of bytes in a HTTP/1.1
* compliant format and sent it to the client. Once the data has been
* encoded it is handed to the transport layer within the server, which may
* choose to buffer the data if the content is too small to send efficiently
* or if the socket is not write ready.
*
* @param buffer
* this is the buffer of bytes to send to the client
* @param off
* this is the offset within the buffer to send from
* @param len
* this is the number of bytes that are to be sent
*/
@Override
public void produce(ByteBuffer buffer, int off, int len) throws IOException {
int pos = 7;
if (this.monitor.isClosed())
throw new ProducerException("Stream has been closed");
if (len > 0) {
for (int num = len; num > 0; num >>>= 4) {
this.size[pos--] = this.index[num & 0xf];
}
try {
this.sender.send(this.size, pos + 1, 9 - pos);
this.sender.send(buffer, off, len);
this.sender.send(this.size, 8, 2);
} catch (Exception cause) {
if (this.sender != null) {
this.monitor.error(this.sender);
}
throw new ProducerException("Error sending response", cause);
}
}
}
/**
* This method is used to flush the contents of the buffer to the client.
* This method will block until such time as all of the data has been sent
* to the client. If at any point there is an error sending the content an
* exception is thrown.
*/
@Override
public void flush() throws IOException {
try {
if (!this.monitor.isClosed()) {
this.sender.flush();
}
} catch (Exception cause) {
if (this.sender != null) {
this.monitor.close(this.sender);
}
throw new ProducerException("Error sending response", cause);
}
}
/**
* This method is used to write the zero length chunk. Writing the zero
* length chunk tells the client that the response has been fully sent, and
* the next sequence of bytes from the HTTP pipeline is the start of the
* next response. This will signal to the server kernel that the next
* request is read to read.
*/
private void finish() throws IOException {
try {
this.sender.send(this.zero);
this.monitor.ready(this.sender);
} catch (Exception cause) {
if (this.sender != null) {
this.monitor.close(this.sender);
}
throw new ProducerException("Error flushing response", cause);
}
}
/**
* This is used to signal to the producer that all content has been written
* and the user no longer needs to write. This will either close the
* underlying transport or it will notify the monitor that the response has
* completed and the next request can begin. This ensures the content is
* flushed to the client.
*/
@Override
public void close() throws IOException {
if (!this.monitor.isClosed()) {
this.finish();
}
}
}