/*
* 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;
import java.io.IOException;
import java.io.InputStream;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
import org.apache.mina.common.ByteBuffer;
import org.apache.mina.common.IoFilterAdapter;
import org.apache.mina.common.IoSession;
import org.apache.mina.common.WriteFuture;
/**
* 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 ByteBuffer} objects and write those buffers
* to the next filter. When end of stream has been reached this filter will
* call {@link NextFilter#messageSent(IoSession, Object)} 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.IoFilter.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 Directory Project (mina-dev@directory.apache.org)
* @version $Rev: 555855 $, $Date: 2007-07-13 12:19:00 +0900 (Fri, 13 Jul 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 String CURRENT_STREAM = StreamWriteFilter.class
.getName()
+ ".stream";
protected static final String WRITE_REQUEST_QUEUE = StreamWriteFilter.class
.getName()
+ ".queue";
protected static final String INITIAL_WRITE_FUTURE = StreamWriteFilter.class
.getName()
+ ".future";
private int writeBufferSize = DEFAULT_STREAM_BUFFER_SIZE;
@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 ConcurrentLinkedQueue<WriteRequest>();
session.setAttribute(WRITE_REQUEST_QUEUE, queue);
}
queue.add(writeRequest);
return;
}
Object message = writeRequest.getMessage();
if (message instanceof InputStream) {
InputStream inputStream = (InputStream) message;
ByteBuffer byteBuffer = getNextByteBuffer(inputStream);
if (byteBuffer == null) {
// End of stream reached.
writeRequest.getFuture().setWritten(true);
nextFilter.messageSent(session, message);
} else {
session.setAttribute(CURRENT_STREAM, inputStream);
session.setAttribute(INITIAL_WRITE_FUTURE, writeRequest
.getFuture());
nextFilter.filterWrite(session, new WriteRequest(byteBuffer));
}
} else {
nextFilter.filterWrite(session, writeRequest);
}
}
@SuppressWarnings("unchecked")
private Queue<WriteRequest> getWriteRequestQueue(IoSession session) {
return (Queue<WriteRequest>) session.getAttribute(WRITE_REQUEST_QUEUE);
}
@Override
public void messageSent(NextFilter nextFilter, IoSession session,
Object message) throws Exception {
InputStream inputStream = (InputStream) session
.getAttribute(CURRENT_STREAM);
if (inputStream == null) {
nextFilter.messageSent(session, message);
} else {
ByteBuffer byteBuffer = getNextByteBuffer(inputStream);
if (byteBuffer == null) {
// End of stream reached.
session.removeAttribute(CURRENT_STREAM);
WriteFuture writeFuture = (WriteFuture) session
.removeAttribute(INITIAL_WRITE_FUTURE);
// Write queued WriteRequests.
Queue<? extends WriteRequest> queue = (Queue<? extends WriteRequest>) session
.removeAttribute(WRITE_REQUEST_QUEUE);
if (queue != null) {
WriteRequest wr = queue.poll();
while (wr != null) {
filterWrite(nextFilter, session, wr);
wr = queue.poll();
}
}
writeFuture.setWritten(true);
nextFilter.messageSent(session, inputStream);
} else {
nextFilter.filterWrite(session, new WriteRequest(byteBuffer));
}
}
}
private ByteBuffer getNextByteBuffer(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;
}
return ByteBuffer.wrap(bytes, 0, off);
}
/**
* 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;
}
}