/*
* 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.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.IoFilterAdapter;
import org.apache.mina.common.IoFilterChain;
import org.apache.mina.common.IoSession;
import org.apache.mina.common.WriteRequest;
import org.apache.mina.util.CircularQueue;
public abstract class AbstractStreamWriteFilter<T> 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 streaming object to the session.
*/
protected final AttributeKey CURRENT_STREAM = new AttributeKey(getClass(), "stream");
protected final AttributeKey WRITE_REQUEST_QUEUE = new AttributeKey(getClass(), "queue");
protected final AttributeKey CURRENT_WRITE_REQUEST = new AttributeKey(getClass(), "writeRequest");
private int writeBufferSize = DEFAULT_STREAM_BUFFER_SIZE;
@Override
public void onPreAdd(IoFilterChain parent, String name,
NextFilter nextFilter) throws Exception {
Class<? extends IoFilterAdapter> clazz = getClass();
if (parent.contains(clazz)) {
throw new IllegalStateException(
"Only one " + clazz.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 CircularQueue<WriteRequest>();
session.setAttribute(WRITE_REQUEST_QUEUE, queue);
}
queue.add(writeRequest);
return;
}
Object message = writeRequest.getMessage();
if (getMessageClass().isInstance(message)) {
T stream = getMessageClass().cast(message);
IoBuffer buffer = getNextBuffer(stream);
if (buffer == null) {
// End of stream reached.
writeRequest.getFuture().setWritten();
nextFilter.messageSent(session, writeRequest);
} else {
session.setAttribute(CURRENT_STREAM, message);
session.setAttribute(CURRENT_WRITE_REQUEST, writeRequest);
nextFilter.filterWrite(session, new DefaultWriteRequest(
buffer));
}
} else {
nextFilter.filterWrite(session, writeRequest);
}
}
abstract protected Class<T> getMessageClass();
@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 {
T stream = getMessageClass().cast(session.getAttribute(CURRENT_STREAM));
if (stream == null) {
nextFilter.messageSent(session, writeRequest);
} else {
IoBuffer buffer = getNextBuffer(stream);
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));
}
}
}
/**
* 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;
}
abstract protected IoBuffer getNextBuffer(T message) throws IOException;
}