/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* 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.
**********************************************************************************************************************/
/**
* This file is based on source code from the Hadoop Project (http://hadoop.apache.org/), licensed by the Apache
* Software Foundation (ASF) under the Apache License, Version 2.0. See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
package eu.stratosphere.nephele.net;
import java.io.EOFException;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.WritableByteChannel;
/**
* This implements an output stream that can have a timeout while writing.
* This sets non-blocking flag on the socket channel.
* So after creating this object , read() on {@link Socket#getInputStream()} and write() on
* {@link Socket#getOutputStream()} on the associated socket will throw
* llegalBlockingModeException.
* Please use {@link SocketInputStream} for reading.
*/
public class SocketOutputStream extends OutputStream implements WritableByteChannel {
private Writer writer;
private static class Writer extends SocketIOWithTimeout {
WritableByteChannel channel;
Writer(WritableByteChannel channel, long timeout)
throws IOException {
super((SelectableChannel) channel, timeout);
this.channel = channel;
}
int performIO(ByteBuffer buf) throws IOException {
return channel.write(buf);
}
}
/**
* Create a new ouput stream with the given timeout. If the timeout
* is zero, it will be treated as infinite timeout. The socket's
* channel will be configured to be non-blocking.
*
* @param channel
* Channel for writing, should also be a {@link SelectableChannel}.
* The channel will be configured to be non-blocking.
* @param timeout
* timeout in milliseconds. must not be negative.
* @throws IOException
*/
public SocketOutputStream(WritableByteChannel channel, long timeout)
throws IOException {
SocketIOWithTimeout.checkChannelValidity(channel);
writer = new Writer(channel, timeout);
}
/**
* Same as SocketOutputStream(socket.getChannel(), timeout):<br>
* <br>
* Create a new ouput stream with the given timeout. If the timeout
* is zero, it will be treated as infinite timeout. The socket's
* channel will be configured to be non-blocking.
*
* @see SocketOutputStream#SocketOutputStream(WritableByteChannel, long)
* @param socket
* should have a channel associated with it.
* @param timeout
* timeout timeout in milliseconds. must not be negative.
* @throws IOException
*/
public SocketOutputStream(Socket socket, long timeout)
throws IOException {
this(socket.getChannel(), timeout);
}
public void write(int b) throws IOException {
/*
* If we need to, we can optimize this allocation.
* probably no need to optimize or encourage single byte writes.
*/
final byte[] buf = new byte[1];
buf[0] = (byte) b;
write(buf, 0, 1);
}
public void write(byte[] b, int off, int len) throws IOException {
final ByteBuffer buf = ByteBuffer.wrap(b, off, len);
while (buf.hasRemaining()) {
try {
if (write(buf) < 0) {
throw new IOException("The stream is closed");
}
} catch (IOException e) {
/*
* Unlike read, write can not inform user of partial writes.
* So will close this if there was a partial write.
*/
if (buf.capacity() > buf.remaining()) {
writer.close();
}
throw e;
}
}
}
public synchronized void close() throws IOException {
/*
* close the channel since Socket.getOuputStream().close()
* closes the socket.
*/
writer.channel.close();
writer.close();
}
/**
* Returns underlying channel used by this stream.
* This is useful in certain cases like channel for {@link FileChannel#transferTo(long, long, WritableByteChannel)}
*/
public WritableByteChannel getChannel() {
return writer.channel;
}
// WritableByteChannle interface
public boolean isOpen() {
return writer.isOpen();
}
public int write(ByteBuffer src) throws IOException {
return writer.doIO(src, SelectionKey.OP_WRITE);
}
/**
* waits for the underlying channel to be ready for writing.
* The timeout specified for this stream applies to this wait.
*
* @throws SocketTimeoutException
* if select on the channel times out.
* @throws IOException
* if any other I/O error occurs.
*/
public void waitForWritable() throws IOException {
writer.waitForIO(SelectionKey.OP_WRITE);
}
/**
* Transfers data from FileChannel using {@link FileChannel#transferTo(long, long, WritableByteChannel)}.
* Similar to readFully(), this waits till requested amount of
* data is transfered.
*
* @param fileCh
* FileChannel to transfer data from.
* @param position
* position within the channel where the transfer begins
* @param count
* number of bytes to transfer.
* @throws EOFException
* If end of input file is reached before requested number of
* bytes are transfered.
* @throws SocketTimeoutException
* If this channel blocks transfer longer than timeout for
* this stream.
* @throws IOException
* Includes any exception thrown by {@link FileChannel#transferTo(long, long, WritableByteChannel)}.
*/
public void transferToFully(FileChannel fileCh, long position, int count) throws IOException {
while (count > 0) {
/*
* Ideally we should wait after transferTo returns 0. But because of
* a bug in JRE on Linux (http://bugs.sun.com/view_bug.do?bug_id=5103988),
* which throws an exception instead of returning 0, we wait for the
* channel to be writable before writing to it. If you ever see
* IOException with message "Resource temporarily unavailable"
* thrown here, please let us know.
* Once we move to JAVA SE 7, wait should be moved to correct place.
*/
waitForWritable();
final int nTransfered = (int) fileCh.transferTo(position, count, getChannel());
if (nTransfered == 0) {
// check if end of file is reached.
if (position >= fileCh.size()) {
throw new EOFException("EOF Reached. file size is " + fileCh.size() + " and " + count
+ " more bytes left to be " + "transfered.");
}
// otherwise assume the socket is full.
// waitForWritable(); // see comment above.
} else if (nTransfered < 0) {
throw new IOException("Unexpected return of " + nTransfered + " from transferTo()");
} else {
position += nTransfered;
count -= nTransfered;
}
}
}
}