org.bitcoinj.net.NioServer 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 java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.channels.*;
import java.nio.channels.spi.SelectorProvider;
import java.util.Iterator;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Throwables;
import com.google.common.util.concurrent.AbstractExecutionThreadService;
import org.slf4j.LoggerFactory;
/**
* Creates a simple server listener which listens for incoming client connections and uses a {@link StreamConnection} to
* process data.
*/
public class NioServer extends AbstractExecutionThreadService {
private static final org.slf4j.Logger log = LoggerFactory.getLogger(NioServer.class);
private final StreamConnectionFactory connectionFactory;
private final ServerSocketChannel sc;
@VisibleForTesting final Selector selector;
// Handle a SelectionKey which was selected
private void handleKey(Selector selector, SelectionKey key) throws IOException {
if (key.isValid() && key.isAcceptable()) {
// Accept a new connection, give it a stream connection as an attachment
SocketChannel newChannel = sc.accept();
newChannel.configureBlocking(false);
SelectionKey newKey = newChannel.register(selector, SelectionKey.OP_READ);
try {
ConnectionHandler handler = new ConnectionHandler(connectionFactory, newKey);
newKey.attach(handler);
handler.connection.connectionOpened();
} catch (IOException e) {
// This can happen if ConnectionHandler's call to get a new handler returned null
log.error("Error handling new connection", Throwables.getRootCause(e).getMessage());
newKey.channel().close();
}
} else { // Got a closing channel or a channel to a client connection
ConnectionHandler.handleKey(key);
}
}
/**
* Creates a new server which is capable of listening for incoming connections and processing client provided data
* using {@link StreamConnection}s created by the given {@link StreamConnectionFactory}
*
* @throws IOException If there is an issue opening the server socket or binding fails for some reason
*/
public NioServer(final StreamConnectionFactory connectionFactory, InetSocketAddress bindAddress) throws IOException {
this.connectionFactory = connectionFactory;
sc = ServerSocketChannel.open();
sc.configureBlocking(false);
sc.socket().bind(bindAddress);
selector = SelectorProvider.provider().openSelector();
sc.register(selector, SelectionKey.OP_ACCEPT);
}
@Override
protected void run() throws Exception {
try {
while (isRunning()) {
selector.select();
Iterator keyIterator = selector.selectedKeys().iterator();
while (keyIterator.hasNext()) {
SelectionKey key = keyIterator.next();
keyIterator.remove();
handleKey(selector, key);
}
}
} catch (Exception e) {
log.error("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.error("Error closing channel", e);
}
try {
key.cancel();
handleKey(selector, key);
} catch (IOException e) {
log.error("Error closing selection key", e);
}
}
try {
selector.close();
} catch (IOException e) {
log.error("Error closing server selector", e);
}
try {
sc.close();
} catch (IOException e) {
log.error("Error closing server channel", e);
}
}
}
/**
* Invoked by the Execution service when it's time to stop.
* Calling this method directly will NOT stop the service, call
* {@link com.google.common.util.concurrent.AbstractExecutionThreadService#stopAsync()} instead.
*/
@Override
public void triggerShutdown() {
// Wake up the selector and let the selection thread break its loop as the ExecutionService !isRunning()
selector.wakeup();
}
}