org.bitcoinj.net.NioClientManager Maven / Gradle / Ivy
/*
* Copyright 2013 Google Inc.
*
* 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.
*/
package org.bitcoinj.net;
import com.google.common.base.Throwables;
import com.google.common.util.concurrent.*;
import org.bitcoinj.utils.*;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.net.ConnectException;
import java.net.SocketAddress;
import java.nio.channels.*;
import java.nio.channels.spi.SelectorProvider;
import java.util.*;
import java.util.concurrent.*;
/**
* A class which manages a set of client connections. Uses Java NIO to select network events and processes them in a
* single network processing thread.
*/
public class NioClientManager extends AbstractExecutionThreadService implements ClientConnectionManager {
private static final org.slf4j.Logger log = LoggerFactory.getLogger(NioClientManager.class);
private final Selector selector;
class PendingConnect {
SocketChannel sc;
StreamParser parser;
SocketAddress address;
SettableFuture future = SettableFuture.create();
PendingConnect(SocketChannel sc, StreamParser parser, SocketAddress address) { this.sc = sc; this.parser = parser; this.address = address; }
}
final Queue newConnectionChannels = new LinkedBlockingQueue();
// Added to/removed from by the individual ConnectionHandler's, thus must by synchronized on its own.
private final Set connectedHandlers = Collections.synchronizedSet(new HashSet());
// Handle a SelectionKey which was selected
private void handleKey(SelectionKey key) throws IOException {
// We could have a !isValid() key here if the connection is already closed at this point
if (key.isValid() && key.isConnectable()) { // ie a client connection which has finished the initial connect process
// Create a ConnectionHandler and hook everything together
PendingConnect data = (PendingConnect) key.attachment();
StreamParser parser = data.parser;
SocketChannel sc = (SocketChannel) key.channel();
ConnectionHandler handler = new ConnectionHandler(parser, key, connectedHandlers);
try {
if (sc.finishConnect()) {
log.info("Successfully connected to {}", sc.socket().getRemoteSocketAddress());
key.interestOps((key.interestOps() | SelectionKey.OP_READ) & ~SelectionKey.OP_CONNECT).attach(handler);
parser.connectionOpened();
data.future.set(data.address);
} else {
log.warn("Failed to connect to {}", sc.socket().getRemoteSocketAddress());
handler.closeConnection(); // Failed to connect for some reason
data.future.setException(new ConnectException("Unknown reason"));
data.future = null;
}
} catch (Exception e) {
// If e is a CancelledKeyException, there is a race to get to interestOps after finishConnect() which
// may cause this. Otherwise it may be any arbitrary kind of connection failure.
// Calling sc.socket().getRemoteSocketAddress() here throws an exception, so we can only log the error itself
Throwable cause = Throwables.getRootCause(e);
log.warn("Failed to connect with exception: {}: {}", cause.getClass().getName(), cause.getMessage());
handler.closeConnection();
data.future.setException(cause);
data.future = null;
}
} else // Process bytes read
ConnectionHandler.handleKey(key);
}
/**
* Creates a new client manager which uses Java NIO for socket management. Uses a single thread to handle all select
* calls.
*/
public NioClientManager() {
try {
selector = SelectorProvider.provider().openSelector();
} catch (IOException e) {
throw new RuntimeException(e); // Shouldn't ever happen
}
}
@Override
public void run() {
try {
Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
while (isRunning()) {
PendingConnect conn;
while ((conn = newConnectionChannels.poll()) != null) {
try {
SelectionKey key = conn.sc.register(selector, SelectionKey.OP_CONNECT);
key.attach(conn);
} catch (ClosedChannelException e) {
log.warn("SocketChannel was closed before it could be registered");
}
}
selector.select();
Iterator keyIterator = selector.selectedKeys().iterator();
while (keyIterator.hasNext()) {
SelectionKey key = keyIterator.next();
keyIterator.remove();
handleKey(key);
}
}
} catch (Exception e) {
log.warn("Error trying to open/read from connection: ", e);
} finally {
// Go through and close everything, without letting IOExceptions get in our way
for (SelectionKey key : selector.keys()) {
try {
key.channel().close();
} catch (IOException e) {
log.warn("Error closing channel", e);
}
key.cancel();
if (key.attachment() instanceof ConnectionHandler)
ConnectionHandler.handleKey(key); // Close connection if relevant
}
try {
selector.close();
} catch (IOException e) {
log.warn("Error closing client manager selector", e);
}
}
}
@Override
public ListenableFuture openConnection(SocketAddress serverAddress, StreamParser parser) {
if (!isRunning())
throw new IllegalStateException();
// Create a new connection, give it a parser as an attachment
try {
SocketChannel sc = SocketChannel.open();
sc.configureBlocking(false);
sc.connect(serverAddress);
PendingConnect data = new PendingConnect(sc, parser, serverAddress);
newConnectionChannels.offer(data);
selector.wakeup();
return data.future;
} catch (Throwable e) {
return Futures.immediateFailedFuture(e);
}
}
@Override
public void triggerShutdown() {
selector.wakeup();
}
@Override
public int getConnectedClientCount() {
return connectedHandlers.size();
}
@Override
public void closeConnections(int n) {
while (n-- > 0) {
ConnectionHandler handler;
synchronized (connectedHandlers) {
handler = connectedHandlers.iterator().next();
}
if (handler != null)
handler.closeConnection(); // Removes handler from connectedHandlers before returning
}
}
@Override
protected Executor executor() {
return new Executor() {
@Override
public void execute(Runnable command) {
new ContextPropagatingThreadFactory("NioClientManager").newThread(command).start();
}
};
}
}