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KitchenSync-core - A Java Library for Distributed Communication
/*
* KitchenSync-core Java Library Copyright (C) 2014 Burton Alexander
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option) any later
* version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
package com.github.mrstampy.kitchensync.stream;
import static com.github.mrstampy.kitchensync.util.KiSyUtils.await;
import io.netty.channel.ChannelFuture;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.net.InetSocketAddress;
import java.util.Arrays;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import rx.Scheduler;
import rx.Subscription;
import rx.functions.Action0;
import rx.schedulers.Schedulers;
import com.github.mrstampy.kitchensync.netty.channel.KiSyChannel;
import com.github.mrstampy.kitchensync.stream.inbound.EndOfMessageInboundMessageHandler;
/**
* Encapsulates a {@link BufferedInputStreamStreamer} and uses an encapsulated
* {@link PipedInputStream} to provide data for the {@link Streamer}. Interface
* methods delegate to the encapsulated {@link Streamer} as appropriate.
*
* @author burton
*
*/
public class ByteArrayStreamer extends AbstractEncapsulatedStreamer {
private static final Logger log = LoggerFactory.getLogger(ByteArrayStreamer.class);
/** The Constant PIPE_SIZE. */
public static final int PIPE_SIZE = 1024 * 2000; // 2 mb
private BufferedInputStream inputStream;
private BufferedOutputStream outputStream;
private AtomicBoolean cancelled = new AtomicBoolean(false);
private AtomicBoolean eom = new AtomicBoolean(false);
private Scheduler svc = Schedulers.from(Executors.newSingleThreadExecutor());
private CountDownLatch latch;
private int pipeSize = PIPE_SIZE;
private int halfPipeSize = pipeSize / 2;
private int waitTime = 10;
private TimeUnit waitUnits = TimeUnit.SECONDS;
private KiSyChannel channel;
private InetSocketAddress destination;
/**
* The Constructor, using the default {@value #PIPE_SIZE} byte pipe.
*
* @param channel
* the channel
* @param destination
* the destination
* @throws Exception
* the exception
*/
public ByteArrayStreamer(KiSyChannel channel, InetSocketAddress destination) throws Exception {
this(channel, destination, PIPE_SIZE);
}
/**
* The Constructor.
*
* @param channel
* the channel
* @param destination
* the destination
* @param pipeSize
* the pipeSize
* @throws Exception
* the exception
*/
public ByteArrayStreamer(KiSyChannel channel, InetSocketAddress destination, int pipeSize) throws Exception {
init(channel, destination, pipeSize);
}
/**
* Exposed to facilitate reuse.
*
* @param channel
* the channel
* @param destination
* the destination
* @param pipeSize
* the pipeSize
* @throws Exception
* the exception
*/
public void init(KiSyChannel channel, InetSocketAddress destination, int pipeSize) throws Exception {
this.pipeSize = pipeSize;
halfPipeSize = pipeSize / 2;
init(channel, destination);
}
/**
* Exposed to facilitate resuse.
*
* @param channel
* the channel
* @param destination
* the destination
* @throws Exception
* the exception
*/
public void init(KiSyChannel channel, InetSocketAddress destination) throws Exception {
log.debug("Initializing streamer from {} to {}", channel.localAddress(), destination);
this.channel = channel;
this.destination = destination;
if (inputStream != null) inputStream.close();
PipedInputStream pis = new PipedInputStream(getPipeSize());
inputStream = new BufferedInputStream(pis);
if (outputStream != null) outputStream.close();
outputStream = new BufferedOutputStream(new PipedOutputStream(pis));
if (getStreamer() != null) cancel();
initializeStreamer();
cancelled.set(false);
}
@Override
protected BufferedInputStreamStreamer createStreamer() throws Exception {
BufferedInputStreamStreamer streamer = new BufferedInputStreamStreamer(inputStream, channel, destination);
streamer.setFinishOnEmptyStream(false);
return streamer;
}
/**
* Delegates to {@link #sendMessage(byte[])} via a single threaded executor.
* The {@link ChannelFuture} returned is specific for the message supplied and
* will indicate completion when the given message has been fully sent or an
* error has occurred.
*
* @param message
* the message
* @return the channel future
* @throws Exception
* the exception
*/
@Override
public ChannelFuture stream(final byte[] message) throws Exception {
final StreamerFuture sf = new StreamerFuture(this);
if (eom.get()) {
getStreamer().init();
eom.set(false);
}
if (message == null) {
log.warn("Null message ignored");
sf.finished(false);
} else {
svc.createWorker().schedule(new Action0() {
@Override
public void call() {
try {
sendMessage(message);
sf.finished(!cancelled.get());
} catch (IOException e) {
sf.finished(false, e);
log.error("Unexpected exception", e);
} finally {
pause();
}
}
});
}
return sf;
}
/**
* Writes the message in up to {@link #getPipeSize()} / 2 chunks and awaits
* until {@link PipedInputStream#available()} returns a value ≤
* {@link #getPipeSize()} / 2 for each chunk to apply a constant positive
* pressure to the encapsulated {@link BufferedInputStreamStreamer}.
*
* @param message
* the message
* @throws IOException
* the IO exception
*/
protected void sendMessage(byte[] message) throws IOException {
int messageLength = message.length;
latch = new CountDownLatch(1);
try {
for (int from = 0; from < messageLength; from += halfPipeSize) {
if (cancelled.get()) return;
int to = getTo(messageLength, from);
writeAndFlush(Arrays.copyOfRange(message, from, to));
}
} finally {
latch.countDown();
}
}
private int getTo(int messageLength, int from) {
int to = from + halfPipeSize;
return to > messageLength ? messageLength : to;
}
/**
* Write and flush.
*
* @param chunk
* the chunk
* @throws IOException
* the IO exception
*/
protected void writeAndFlush(byte[] chunk) throws IOException {
outputStream.write(chunk);
outputStream.flush();
if (!isStreaming()) stream();
awaitFlush();
}
/**
* Awaits for the {@link PipedInputStream#available()} to return a value ≤
* {@link #getPipeSize()} / 2. Times out after 10 seconds and if timed out
* will recurse until {@link #cancel()}led or successful completion.
*
* @throws IOException
* the IO exception
*/
protected void awaitFlush() throws IOException {
CountDownLatch cdl = new CountDownLatch(1);
Subscription sub = startAwaitThread(cdl);
boolean ok = await(cdl, waitTime, waitUnits);
sub.unsubscribe();
if (!ok && !cancelled.get()) {
log.warn("Cannot finish sending after 10 seconds, retrying");
awaitFlush();
}
}
/**
* Start await thread for the {@link PipedInputStream} to be cleared by the
* {@link Streamer}.
*
* @param cdl
* the cdl
* @return the subscription
*/
protected Subscription startAwaitThread(final CountDownLatch cdl) {
return Schedulers.computation().createWorker().schedulePeriodically(new Action0() {
@Override
public void call() {
try {
if (inputStream.available() > halfPipeSize) return;
} catch (IOException e) {
log.error("Unexpected exception", e);
}
cdl.countDown();
}
}, 0, 5, TimeUnit.MILLISECONDS);
}
/*
* (non-Javadoc)
*
* @see com.github.mrstampy.kitchensync.stream.Streamer#cancel()
*/
@Override
public void cancel() {
getStreamer().cancel();
cancelled.set(true);
}
/**
* Not implemented.
*
* @return the long
*/
@Override
public long size() {
return -1;
}
/**
* Exposing throttling
*
* @return the microseconds to throttle between chunks
* @see AbstractStreamer#getThrottle()
*/
public int getThrottle() {
return getStreamer().getThrottle();
}
/**
* Exposing throttling
*
* @param throttle
* the microseconds to throttle between chunks
* @see AbstractStreamer#setThrottle(int)
*/
public void setThrottle(int throttle) {
getStreamer().setThrottle(throttle);
}
/**
* Send end of message.
*
* @see EndOfMessageRegister
* @see EndOfMessageListener
* @see EndOfMessageInboundMessageHandler
*/
public void sendEndOfMessage() {
await(latch, 100, TimeUnit.MILLISECONDS);
getStreamer().sendEndOfMessage();
eom.set(true);
}
/**
* Returns the size of the pipe used to move bytes around.
*
* @return the size of the pipe
* @see #PIPE_SIZE
* @see #init(KiSyChannel, InetSocketAddress, int)
*/
public int getPipeSize() {
return pipeSize;
}
/**
* Specifies the amount of time to wait until the next {@link #getPipeSize()}
* / 2 chunk can be written to the output stream. Should the wait time out the
* {@link #awaitFlush()} method is recursively called. Defaults to 10 seconds.
*
* @param waitTime
* the value to wait
* @param waitUnits
* the units to wait
*/
public void setWaitTime(int waitTime, TimeUnit waitUnits) {
if (waitTime < 0) throw new IllegalArgumentException("wait time must be >= 0: " + waitTime);
if (waitUnits == null) throw new IllegalArgumentException("Units must be specified");
this.waitTime = waitTime;
this.waitUnits = waitUnits;
}
}