/*
* 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.
*
*/
package org.apache.mina.filter.stream;
import java.io.IOException;
import java.io.InputStream;
import java.util.LinkedList;
import java.util.Queue;
import org.apache.mina.common.AttributeKey;
import org.apache.mina.common.DefaultWriteRequest;
import org.apache.mina.common.IoBuffer;
import org.apache.mina.common.IoFilter;
import org.apache.mina.common.IoFilterAdapter;
import org.apache.mina.common.IoFilterChain;
import org.apache.mina.common.IoSession;
import org.apache.mina.common.WriteRequest;
/**
* Filter implementation which makes it possible to write {@link InputStream}
* objects directly using {@link IoSession#write(Object)}. When an
* {@link InputStream} is written to a session this filter will read the bytes
* from the stream into {@link IoBuffer} objects and write those buffers
* to the next filter. When end of stream has been reached this filter will
* call {@link IoFilter.NextFilter#messageSent(IoSession,WriteRequest)} using the original
* {@link InputStream} written to the session and notifies
* {@link org.apache.mina.common.WriteFuture} on the
* original {@link org.apache.mina.common.WriteRequest}.
* <p/>
* This filter will ignore written messages which aren't {@link InputStream}
* instances. Such messages will be passed to the next filter directly.
* </p>
* <p/>
* NOTE: this filter does not close the stream after all data from stream
* has been written. The {@link org.apache.mina.common.IoHandler} should take
* care of that in its
* {@link org.apache.mina.common.IoHandler#messageSent(IoSession,Object)}
* callback.
* </p>
*
* @author The Apache MINA Project (dev@mina.apache.org)
* @version $Rev: 591933 $, $Date: 2007-11-05 18:36:01 +0900 (Mon, 05 Nov 2007) $
*/
public class StreamWriteFilter extends IoFilterAdapter {
/**
* The default buffer size this filter uses for writing.
*/
public static final int DEFAULT_STREAM_BUFFER_SIZE = 4096;
/**
* The attribute name used when binding the {@link InputStream} to the session.
*/
public static final AttributeKey CURRENT_STREAM = new AttributeKey(StreamWriteFilter.class, "stream");
static final AttributeKey WRITE_REQUEST_QUEUE = new AttributeKey(StreamWriteFilter.class, "queue");
static final AttributeKey CURRENT_WRITE_REQUEST = new AttributeKey(StreamWriteFilter.class, "writeRequest");
private int writeBufferSize = DEFAULT_STREAM_BUFFER_SIZE;
@Override
public void onPreAdd(IoFilterChain parent, String name, NextFilter nextFilter) throws Exception {
if(parent.contains(StreamWriteFilter.class)) {
throw new IllegalStateException("Only one " + StreamWriteFilter.class.getName()
+ " is permitted.");
}
}
@Override
public void filterWrite(NextFilter nextFilter, IoSession session, WriteRequest writeRequest)
throws Exception {
// If we're already processing a stream we need to queue the WriteRequest.
if(session.getAttribute(CURRENT_STREAM) != null) {
Queue<WriteRequest> queue = getWriteRequestQueue(session);
if(queue == null) {
queue = new LinkedList<WriteRequest>();
session.setAttribute(WRITE_REQUEST_QUEUE, queue);
}
queue.add(writeRequest);
return;
}
Object message = writeRequest.getMessage();
if(message instanceof InputStream) {
InputStream inputStream = (InputStream) message;
IoBuffer buffer = getNextBuffer(inputStream);
if(buffer == null) {
// End of stream reached.
writeRequest.getFuture().setWritten();
nextFilter.messageSent(session, writeRequest);
} else {
session.setAttribute(CURRENT_STREAM, inputStream);
session.setAttribute(CURRENT_WRITE_REQUEST, writeRequest);
nextFilter.filterWrite(session, new DefaultWriteRequest(buffer));
}
} else {
nextFilter.filterWrite(session, writeRequest);
}
}
@SuppressWarnings("unchecked")
private Queue<WriteRequest> getWriteRequestQueue(IoSession session) {
return (Queue<WriteRequest>) session.getAttribute(WRITE_REQUEST_QUEUE);
}
@SuppressWarnings("unchecked")
private Queue<WriteRequest> removeWriteRequestQueue(IoSession session) {
return (Queue<WriteRequest>) session.removeAttribute(WRITE_REQUEST_QUEUE);
}
@Override
public void messageSent(NextFilter nextFilter, IoSession session, WriteRequest writeRequest)
throws Exception {
InputStream inputStream = (InputStream) session.getAttribute(CURRENT_STREAM);
if(inputStream == null) {
nextFilter.messageSent(session, writeRequest);
} else {
IoBuffer buffer = getNextBuffer(inputStream);
if(buffer == null) {
// End of stream reached.
session.removeAttribute(CURRENT_STREAM);
WriteRequest currentWriteRequest = (WriteRequest) session.removeAttribute(CURRENT_WRITE_REQUEST);
// Write queued WriteRequests.
Queue<WriteRequest> queue = removeWriteRequestQueue(session);
if(queue != null) {
WriteRequest wr = queue.poll();
while(wr != null) {
filterWrite(nextFilter, session, wr);
wr = queue.poll();
}
}
currentWriteRequest.getFuture().setWritten();
nextFilter.messageSent(session, currentWriteRequest);
} else {
nextFilter.filterWrite(session, new DefaultWriteRequest(buffer));
}
}
}
private IoBuffer getNextBuffer(InputStream is) throws IOException {
byte[] bytes = new byte[writeBufferSize];
int off = 0;
int n = 0;
while(off < bytes.length && (n = is.read(bytes, off, bytes.length - off)) != -1) {
off += n;
}
if(n == -1 && off == 0) {
return null;
}
IoBuffer buffer = IoBuffer.wrap(bytes, 0, off);
return buffer;
}
/**
* Returns the size of the write buffer in bytes. Data will be read from the
* stream in chunks of this size and then written to the next filter.
*
* @return the write buffer size.
*/
public int getWriteBufferSize() {
return writeBufferSize;
}
/**
* Sets the size of the write buffer in bytes. Data will be read from the
* stream in chunks of this size and then written to the next filter.
*
* @throws IllegalArgumentException if the specified size is < 1.
*/
public void setWriteBufferSize(int writeBufferSize) {
if(writeBufferSize < 1) {
throw new IllegalArgumentException("writeBufferSize must be at least 1");
}
this.writeBufferSize = writeBufferSize;
}
}