org.apache.activemq.transport.nio.NIOOutputStream Maven / Gradle / Ivy
/**
* 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.activemq.transport.nio;
import java.io.EOFException;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.WritableByteChannel;
import javax.net.ssl.SSLEngine;
import org.apache.activemq.transport.tcp.TimeStampStream;
/**
* An optimized buffered OutputStream for TCP/IP
*/
public class NIOOutputStream extends OutputStream implements TimeStampStream {
private static final int BUFFER_SIZE = 8196;
private final WritableByteChannel out;
private final byte[] buffer;
private final ByteBuffer byteBuffer;
private int count;
private boolean closed;
private volatile long writeTimestamp = -1; // concurrent reads of this value
private SSLEngine engine;
/**
* Constructor
*
* @param out
* the channel to write data to.
*/
public NIOOutputStream(WritableByteChannel out) {
this(out, BUFFER_SIZE);
}
/**
* Creates a new buffered output stream to write data to the specified
* underlying output stream with the specified buffer size.
*
* @param out
* the underlying output stream.
* @param size
* the buffer size.
*
* @throws IllegalArgumentException if size <= 0.
*/
public NIOOutputStream(WritableByteChannel out, int size) {
this.out = out;
if (size <= 0) {
throw new IllegalArgumentException("Buffer size <= 0");
}
buffer = new byte[size];
byteBuffer = ByteBuffer.wrap(buffer);
}
/**
* write a byte on to the stream
*
* @param b
* byte to write
*
* @throws IOException if an error occurs while writing the data.
*/
@Override
public void write(int b) throws IOException {
checkClosed();
if (availableBufferToWrite() < 1) {
flush();
}
buffer[count++] = (byte) b;
}
/**
* write a byte array to the stream
*
* @param b
* the byte buffer
* @param off
* the offset into the buffer
* @param len
* the length of data to write
*
* @throws IOException if an error occurs while writing the data.
*/
@Override
public void write(byte b[], int off, int len) throws IOException {
checkClosed();
if (availableBufferToWrite() < len) {
flush();
}
if (buffer.length >= len) {
System.arraycopy(b, off, buffer, count, len);
count += len;
} else {
write(ByteBuffer.wrap(b, off, len));
}
}
/**
* flush the data to the output stream This doesn't call flush on the
* underlying OutputStream, because TCP/IP is particularly efficient at doing
* this itself ....
*
* @throws IOException if an error occurs while writing the data.
*/
@Override
public void flush() throws IOException {
if (count > 0 && out != null) {
byteBuffer.position(0);
byteBuffer.limit(count);
write(byteBuffer);
count = 0;
}
}
/**
* close this stream
*
* @throws IOException
*/
@Override
public void close() throws IOException {
super.close();
if (engine != null) {
engine.closeOutbound();
}
closed = true;
}
/**
* Checks that the stream has not been closed
*
* @throws IOException
*/
protected void checkClosed() throws IOException {
if (closed) {
throw new EOFException("Cannot write to the stream any more it has already been closed");
}
}
/**
* @return the amount free space in the buffer
*/
private int availableBufferToWrite() {
return buffer.length - count;
}
protected void write(ByteBuffer data) throws IOException {
ByteBuffer plain;
if (engine != null) {
plain = ByteBuffer.allocate(engine.getSession().getPacketBufferSize());
plain.clear();
engine.wrap(data, plain);
plain.flip();
} else {
plain = data;
}
int remaining = plain.remaining();
long delay = 1;
int lastWriteSize = -1;
try {
writeTimestamp = System.currentTimeMillis();
while (remaining > 0) {
// We may need to do a little bit of sleeping to avoid a busy
// loop. Slow down if no data was written out..
if (lastWriteSize == 0) {
try {
// Use exponential growth to increase sleep time.
Thread.sleep(delay);
delay *= 2;
if (delay > 1000) {
delay = 1000;
}
} catch (InterruptedException e) {
throw new InterruptedIOException();
}
} else {
delay = 1;
}
// Since the write is non-blocking, all the data may not have
// been written.
lastWriteSize = out.write(plain);
// if the data buffer was larger than the packet buffer we might
// need to wrap more packets until we reach the end of data, but only
// when plain has no more space since we are non-blocking and a write
// might not have written anything.
if (engine != null && data.hasRemaining() && !plain.hasRemaining()) {
plain.clear();
engine.wrap(data, plain);
plain.flip();
}
remaining = plain.remaining();
}
} finally {
writeTimestamp = -1;
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.transport.tcp.TimeStampStream#isWriting()
*/
@Override
public boolean isWriting() {
return writeTimestamp > 0;
}
/*
* (non-Javadoc)
*
* @see
* org.apache.activemq.transport.tcp.TimeStampStream#getWriteTimestamp()
*/
@Override
public long getWriteTimestamp() {
return writeTimestamp;
}
public void setEngine(SSLEngine engine) {
this.engine = engine;
}
}