/**
* 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.openejb.server.discovery;
import org.apache.openejb.monitoring.Event;
import org.apache.openejb.monitoring.Managed;
import org.apache.openejb.server.ServerRuntimeException;
import org.apache.openejb.util.DaemonThreadFactory;
import org.apache.openejb.util.Duration;
import org.apache.openejb.util.Join;
import org.apache.openejb.util.LogCategory;
import org.apache.openejb.util.Logger;
import java.io.ByteArrayOutputStream;
import java.io.EOFException;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.URI;
import java.nio.ByteBuffer;
import java.nio.channels.CancelledKeyException;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.FutureTask;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/**
* @version $Rev$ $Date$
*/
@Managed
public class MultipointServer {
private static final Logger log = Logger.getInstance(LogCategory.OPENEJB_SERVER.createChild("discovery").createChild("multipoint"), MultipointServer.class);
private static final URI END_LIST = URI.create("end:list");
private final int port;
private final URI me;
private final Set<URI> roots = new LinkedHashSet<URI>();
private final Event runs = new Event();
private final Event heartbeats = new Event();
private final Event reconnects = new Event();
private final Event sessionsCreated = new Event();
/**
* Only used for toString to make debugging easier
*/
private final String name;
private final Tracker tracker;
private final LinkedList<Host> connect = new LinkedList<Host>();
private final Map<URI, Session> connections = new HashMap<URI, Session>();
private long joined = 0;
private final long reconnectDelay;
private final ServerSocketChannel serverChannel;
private final Selector selector;
private final Lock lock = new ReentrantLock();
private final Condition started = lock.newCondition();
private final Condition stopped = lock.newCondition();
public MultipointServer(final int port, final Tracker tracker) throws IOException {
this("localhost", "localhost", port, tracker, randomColor(), true, new HashSet<URI>(0), new Duration(30, TimeUnit.SECONDS));
}
public MultipointServer(final String bindHost, String broadcastHost, final int port, final Tracker tracker, final String name, final boolean debug, final Set<URI> roots, Duration reconnectDelay) throws IOException {
if (tracker == null)
throw new NullPointerException("tracker cannot be null");
if (bindHost == null)
throw new NullPointerException("host cannot be null");
if (broadcastHost == null)
broadcastHost = bindHost;
if (reconnectDelay == null)
reconnectDelay = new Duration(30, TimeUnit.SECONDS);
this.tracker = tracker;
this.name = name;
if (roots != null) {
for (final URI uri : roots) {
this.roots.add(normalize(uri));
}
}
this.reconnectDelay = reconnectDelay.getTime(TimeUnit.NANOSECONDS);
final String format = String.format("MultipointServer(bindHost=%s, discoveryHost=%s, port=%s, name=%s, debug=%s, roots=%s, reconnectDelay='%s')",
bindHost,
broadcastHost,
port,
name,
debug,
this.roots.size(),
reconnectDelay.toString());
log.debug(format);
selector = Selector.open();
final InetSocketAddress address = new InetSocketAddress(bindHost, port);
serverChannel = ServerSocketChannel.open();
serverChannel.configureBlocking(false);
final ServerSocket serverSocket = serverChannel.socket();
serverSocket.bind(address);
this.port = serverSocket.getLocalPort();
me = createURI(broadcastHost, this.port);
serverChannel.register(selector, SelectionKey.OP_ACCEPT);
println("Broadcasting");
}
private URI normalize(final URI uri) {
return createURI(uri.getHost(), uri.getPort());
}
private URI createURI(final String host, final int port) {
return URI.create("conn://" + host.toLowerCase() + ":" + port);
}
public URI getMe() {
return me;
}
public Set<URI> getRoots() {
return roots;
}
public Event getRuns() {
return runs;
}
public Event getHeartbeats() {
return heartbeats;
}
public Event getReconnects() {
return reconnects;
}
public Event getSessionsCreated() {
return sessionsCreated;
}
public String getName() {
return name;
}
public long getJoined() {
return joined;
}
public List<URI> getSessions() {
return new ArrayList<URI>(connections.keySet());
}
public List<URI> getConnectionsQueued() {
synchronized (connect) {
final ArrayList<URI> uris = new ArrayList<URI>(connect.size());
for (final Host host : connect) {
uris.add(host.getUri());
}
return uris;
}
}
public long getReconnectDelay() {
return reconnectDelay;
}
public int getPort() {
return port;
}
/**
* Attempt to connect back to the network if
* - We aren't already connected
* - We aren't already attempting to connect
* - It has been a while since we last tried (reconnectDelay)
*/
private void rejoin() {
if (roots.size() <= 0)
return;
if (System.nanoTime() - joined <= reconnectDelay)
return;
for (final URI uri : roots) {
final Host host = new Host(uri);
synchronized (connect) {
if (!connections.containsKey(uri) && !connect.contains(host)) {
log.info("Reconnect{uri=" + uri + "}");
connect.addLast(host);
host.resolveDns();
this.joined = System.nanoTime();
}
}
}
}
public MultipointServer start() {
if (running.compareAndSet(false, true)) {
final String multipointServer = Join.join(".", "MultipointServer", name, port);
log.info("MultipointServer Starting : Thread '" + multipointServer + "'");
final Thread thread = new Thread(new Runnable() {
@Override
public void run() {
signal(started);
try {
_run();
} finally {
signal(stopped);
}
}
});
thread.setName(multipointServer);
thread.start();
await(started, 10, TimeUnit.SECONDS);
}
return this;
}
private void signal(final Condition condition) {
lock.lock();
try {
condition.signal();
} finally {
lock.unlock();
}
}
private void await(final Condition condition, final long time, final TimeUnit unit) {
lock.lock();
try {
condition.await(time, unit);
} catch (final InterruptedException e) {
Thread.interrupted();
} finally {
lock.unlock();
}
}
public void stop() {
running.set(false);
try {
serverChannel.close();
} catch (final IOException e) {
throw new CloseException(e);
} finally {
await(stopped, 10, TimeUnit.SECONDS);
}
}
public static class CloseException extends RuntimeException {
public CloseException(final Throwable cause) {
super(cause);
}
}
public class Session {
private static final int EOF = 3;
private final SocketChannel channel;
private final ByteBuffer read = ByteBuffer.allocate(1024);
private final SelectionKey key;
private final List<URI> listed = new ArrayList<URI>();
private final long created = System.currentTimeMillis();
private ByteBuffer write;
@Managed
private State state = State.OPEN;
private URI uri;
public boolean hangup;
private final boolean client;
public Session(final SocketChannel channel, final InetSocketAddress address, final URI uri) throws ClosedChannelException {
this.channel = channel;
this.client = uri != null;
this.uri = uri != null ? uri : createURI(address.getHostName(), address.getPort());
this.key = channel.register(selector, 0, this);
sessionsCreated.record();
log.info("Constructing " + this);
}
public Session ops(final int ops) {
key.interestOps(ops);
return this;
}
public long getCreated() {
return created;
}
public void state(final int ops, final State state) {
// trace("transition "+state +" "+ops);
if (this.state != state) {
if (log.isDebugEnabled()) {
log.debug(message(state.name()));
}
}
this.state = state;
if (ops > 0)
key.interestOps(ops);
}
public void setURI(final URI uri) {
this.uri = uri;
}
private void trace(final String str) {
// println(message(str));
if (log.isDebugEnabled()) {
log.debug(message(str));
// new Exception().fillInStackTrace().printStackTrace();
}
}
private void info(final String str) {
// println(message(str));
if (log.isInfoEnabled()) {
log.info(message(str));
}
}
private String message(final String str) {
final StringBuilder sb = new StringBuilder();
sb.append(name);
sb.append(":");
sb.append(port);
sb.append(" ");
if (key.isValid()) {
if ((key.interestOps() & SelectionKey.OP_READ) == SelectionKey.OP_READ)
sb.append("<");
if ((key.interestOps() & SelectionKey.OP_WRITE) == SelectionKey.OP_WRITE)
sb.append(">");
if ((key.interestOps() == 0))
sb.append("-");
} else {
sb.append(":");
}
sb.append(" ");
sb.append(uri.getPort());
sb.append(" ");
sb.append(this.state);
sb.append(" ");
sb.append(str);
return sb.toString();
}
public void write(final URI uri) throws IOException {
write(Arrays.asList(uri));
}
public void write(final Collection<?> uris) throws IOException {
final ByteArrayOutputStream baos = new ByteArrayOutputStream();
for (final Object uri : uris) {
final String s = uri.toString();
final byte[] b = s.getBytes("UTF-8");
baos.write(b);
baos.write(EOF);
}
this.write = ByteBuffer.wrap(baos.toByteArray());
}
public boolean drain() throws IOException {
this.channel.write(write);
return write.remaining() == 0;
}
public String read() throws IOException {
if (channel.read(read) == -1)
throw new EOFException();
final byte[] buf = read.array();
final int end = endOfText(buf, 0, read.position());
if (end < 0)
return null;
// Copy the string without the terminator char
final String text = new String(buf, 0, end, "UTF-8");
final int newPos = read.position() - end;
System.arraycopy(buf, end + 1, buf, 0, newPos - 1);
read.position(newPos - 1);
return text;
}
private int endOfText(final byte[] data, final int offset, final int pos) {
for (int i = offset; i < pos; i++) {
if (data[i] == EOF)
return i;
}
return -1;
}
@Override
public String toString() {
return "Session{" +
"uri=" + uri +
", created=" + created +
", state=" + state +
", owner=" + port +
", s=" + (client ? channel.socket().getPort() : channel.socket().getLocalPort()) +
", c=" + (!client ? channel.socket().getPort() : channel.socket().getLocalPort()) +
", " + (client ? "client" : "server") +
'}';
}
private long last = 0;
public void tick() throws IOException {
if (state != State.HEARTBEAT)
return;
final long now = System.currentTimeMillis();
final long delay = now - last;
if (delay >= tracker.getHeartRate()) {
last = now;
heartbeat();
}
}
private void heartbeat() throws IOException {
heartbeats.record();
final Set<String> strings = tracker.getRegisteredServices();
// for (String string : strings) {
// trace(string);
// }
write(strings);
state(SelectionKey.OP_READ | SelectionKey.OP_WRITE, State.HEARTBEAT);
}
}
private static enum State {
OPEN,
GREETING,
LISTING,
HEARTBEAT,
CLOSED
}
private final AtomicBoolean running = new AtomicBoolean();
private void _run() {
// The selectorTimeout ensures that even when there are no IO events,
// this loop will "wake up" and execute at least as frequently as the
// expected heartrate.
//
// We initiate WRITE events (the heartbeats we send) in this loop, so that
// detail is critical.
long selectorTimeout = tracker.getHeartRate();
// For reliability purposes we will actually adjust the selectorTimeout
// on each iteration of the loop, shrinking it down just a little to a
// account for the execution time of the loop itself.
int failed = 0;
while (running.get()) {
runs.record();
final long start = System.nanoTime();
try {
selector.select(selectorTimeout);
failed = 0;
} catch (final IOException ex) {
if (failed++ > 100) {
log.fatal("Too many Multipoint Failures. Terminating service.", ex);
return;
}
log.error("Multipoint Failure.", ex);
try {
Thread.sleep(100);
} catch (final InterruptedException e) {
Thread.interrupted();
}
}
final Set keys = selector.selectedKeys();
final Iterator iterator = keys.iterator();
while (iterator.hasNext()) {
final SelectionKey key = (SelectionKey) iterator.next();
iterator.remove();
try {
if (key.isAcceptable())
doAccept(key);
if (key.isConnectable())
doConnect(key);
if (key.isReadable())
doRead(key);
if (key.isWritable())
doWrite(key);
} catch (final CancelledKeyException ex) {
synchronized (connect) {
final Session session = (Session) key.attachment();
if (session.state != State.CLOSED) {
close(key);
}
}
} catch (final ClosedChannelException ex) {
synchronized (connect) {
final Session session = (Session) key.attachment();
if (session.state != State.CLOSED) {
close(key);
}
}
} catch (final IOException ex) {
final Session session = (Session) key.attachment();
session.trace(ex.getClass().getSimpleName() + ": " + ex.getMessage());
close(key);
}
}
// This loop can generate WRITE keys (the heartbeats we send)
for (final SelectionKey key : selector.keys()) {
final Session session = (Session) key.attachment();
try {
if (session != null && session.state == State.HEARTBEAT)
session.tick();
} catch (final IOException ex) {
close(key);
}
}
// Here is where we actually will expire missing services
tracker.checkServices();
// Fill 'connections' list if we are fully disconnected
rejoin();
// Connect to anyone in the 'connections' list
initiateConnections();
// Adjust selector timeout so we execute in even increments
// This keeps the heartbeat and rejoin regular
selectorTimeout = adjustedSelectorTimeout(start);
}
log.info("MultipointServer has terminated.");
}
private long adjustedSelectorTimeout(final long start) {
final long end = System.nanoTime();
final long elapsed = TimeUnit.NANOSECONDS.toMillis(end - start);
final long heartRate = tracker.getHeartRate();
return Math.max(1, heartRate - elapsed);
}
private void initiateConnections() {
synchronized (connect) {
final LinkedList<Host> unresolved = new LinkedList<Host>();
while (connect.size() > 0) {
final Host host = connect.removeFirst();
log.debug("Initiate(uri=" + host.getUri() + ")");
if (connections.containsKey(host.getUri()))
continue;
if (!host.isDone()) {
unresolved.add(host);
log.debug("Unresolved(uri=" + host.getUri() + ")");
continue;
}
final InetSocketAddress address;
try {
address = host.getSocketAddress();
} catch (final ExecutionException e) {
final Throwable t = (e.getCause() != null) ? e.getCause() : e;
final String message = String.format("Failed Connect{uri=%s} %s{message=\"%s\"}", host.getUri(), t.getClass().getSimpleName(), t.getMessage());
log.warning(message);
continue;
} catch (final TimeoutException e) {
unresolved.add(host);
log.debug("Unresolved(uri=" + host.getUri() + ")");
continue;
}
try {
final URI uri = host.getUri();
println("open " + uri);
// Create a non-blocking NIO channel
final SocketChannel socketChannel = SocketChannel.open();
socketChannel.configureBlocking(false);
socketChannel.connect(address);
final Session session = new Session(socketChannel, address, uri);
session.ops(SelectionKey.OP_CONNECT);
session.trace("client");
connections.put(session.uri, session);
// seen - needs to get maintained as "connected"
// TODO remove from seen
} catch (final IOException e) {
throw new ServerRuntimeException(e);
}
}
connect.addAll(unresolved);
}
}
private void doWrite(final SelectionKey key) throws IOException {
final Session session = (Session) key.attachment();
switch (session.state) {
case GREETING: { // write
// Only CLIENTs write a GREETING message
// As we are a client, the first thing we do
// is READ the server's LIST
if (session.drain()) {
session.state(SelectionKey.OP_READ, State.LISTING);
}
}
break;
case LISTING: { // write
if (session.drain()) {
if (session.client) {
// CLIENTs list last, so at this point we've read
// the server's list and have written ours
// session.trace("DONE WRITING");
session.state(SelectionKey.OP_READ, State.HEARTBEAT);
} else {
// SERVERs always write their list first, so at this
// point we switch to LIST READ mode
session.state(SelectionKey.OP_READ, State.LISTING);
}
}
}
break;
case HEARTBEAT: { // write
if (session.drain()) {
session.last = System.currentTimeMillis();
// session.trace("send");
session.state(SelectionKey.OP_READ, State.HEARTBEAT);
}
}
break;
}
}
private void doRead(final SelectionKey key) throws IOException {
final Session session = (Session) key.attachment();
switch (session.state) {
case GREETING: { // read
// This state is only reachable as a SERVER
// The client connected and said hello by sending
// its URI to let us know who they are
// Once this is read, the client will expect us
// to send our full list of URIs followed by the
// "end" address.
// So we switch to WRITE LISTING and they switch
// to READ LISTING
// Then we will switch to READ LISTING and they
// will switch to WRITE LISTING
final String message = session.read();
if (message == null)
break; // need to read more
session.setURI(URI.create(message));
connected(session);
session.trace("welcome");
final ArrayList<URI> list = connections();
// When they read themselves on the list
// they'll know it's time to list their URIs
list.remove(me); // yank
list.add(END_LIST); // add to the end
session.write(list);
session.state(SelectionKey.OP_WRITE, State.LISTING);
session.trace("STARTING");
}
break;
case LISTING: { // read
String message;
while ((message = session.read()) != null) {
// session.trace(message);
final URI uri = URI.create(message);
if (END_LIST.equals(uri)) {
if (session.client) {
final ArrayList<URI> list = connections();
for (final URI reported : session.listed) {
list.remove(reported);
}
// When they read us on the list
// they'll know it's time to switch to heartbeat
list.remove(session.uri);
list.add(END_LIST);
session.write(list);
session.state(SelectionKey.OP_WRITE, State.LISTING);
} else {
// We are a SERVER in this relationship, so we will have already
// listed our known peers by this point. From here we switch to
// heartbeating
// heartbeat time
if (session.hangup) {
session.state(0, State.CLOSED);
session.trace("hangup");
hangup(key);
} else {
session.trace("DONE READING");
session.state(SelectionKey.OP_READ, State.HEARTBEAT);
}
}
break;
} else {
session.listed.add(uri);
try {
connect(uri);
} catch (final Exception e) {
println("connect failed " + uri + " - " + e.getMessage());
e.printStackTrace();
}
}
}
}
break;
case HEARTBEAT: { // read
String message;
while ((message = session.read()) != null) {
// session.trace(message);
tracker.processData(message);
}
}
break;
}
}
private void doConnect(final SelectionKey key) throws IOException {
// we are a client
final Session session = (Session) key.attachment();
session.channel.finishConnect();
session.trace("connected");
// when you are a client, first say high to everyone
// before accepting data
// once a server reads our address, it will send it's
// full list of known addresses, followed by the "end"
// address to signal that it is done.
// we will then send our full list of known addresses,
// followed by the "end" address to signal we are done.
// Afterward the server will only pulls its heartbeat
// separately, we will initiate connections to everyone
// in the list who we have not yet seen.
// WRITE our GREETING
session.write(me);
session.state(SelectionKey.OP_WRITE, State.GREETING);
}
private void doAccept(final SelectionKey key) throws IOException {
// we are a server
// when you are a server, we must first listen for the
// address of the client before sending data.
// once they send us their address, we will send our
// full list of known addresses, followed by the "end"
// address to signal that we are done.
// Afterward we will only pulls our heartbeat
final ServerSocketChannel server = (ServerSocketChannel) key.channel();
final SocketChannel client = server.accept();
final InetSocketAddress address = (InetSocketAddress) client.socket().getRemoteSocketAddress();
client.configureBlocking(false);
final Session session = new Session(client, address, null);
session.trace("accept");
session.state(SelectionKey.OP_READ, State.GREETING);
}
private ArrayList<URI> connections() {
synchronized (connect) {
final ArrayList<URI> list = new ArrayList<URI>(connections.keySet());
for (final Host host : connect) {
list.add(host.getUri());
}
return list;
}
}
private void close(final SelectionKey key) {
final Session session = (Session) key.attachment();
if (session.hangup) {
// This was a duplicate connection and was closed
// do not remove this URI from the 'connections'
// map as this particular session is not in that
// map -- only the good session that will not be
// closed is in there.
log.info("Hungup " + session);
session.trace("hungup");
} else {
log.info("Closed " + session);
session.trace("closed");
synchronized (connect) {
connections.remove(session.uri);
}
}
session.state(0, State.CLOSED);
hangup(key);
}
private void hangup(final SelectionKey key) {
key.cancel();
try {
key.channel().close();
} catch (final IOException cex) {
//Ignore
}
}
public void connect(final MultipointServer s) throws Exception {
connect(s.port);
}
public void connect(final int port) throws Exception {
connect(URI.create("conn://localhost:" + port));
}
public void connect(URI uri) {
uri = normalize(uri);
if (me.equals(uri))
return;
final Host host = new Host(uri);
synchronized (connect) {
if (!connections.containsKey(uri) && !connect.contains(host)) {
log.info("Queuing{uri=" + uri + "}");
connect.addLast(host);
host.resolveDns();
}
}
}
private void connected(Session session) {
synchronized (connect) {
Session duplicate = connections.get(session.uri);
// Session duplicate = null;
if (duplicate != null) {
session.trace("duplicate");
// At this point we know we have two sockets open
// to the client, this can happen in two different ways
//
// 1. one created by them and one created by us.
// 2. two created by them and none created by us.
//
// For case #1, we will both have detected this situation
// and know it needs fixing. Only one of us can hangup
//
// For case #2, the client was likely disconnected and
// is calling back.
final Session[] sessions = {session, duplicate};
if (!sessions[0].client && !sessions[1].client) {
// Case 1 -- Client is calling back
Arrays.sort(sessions, new Comparator<Session>() {
@Override
public int compare(final Session a, final Session b) {
return (int) (b.created - a.created);
}
});
} else {
// Case 2 -- We called each other at the same time
Arrays.sort(sessions, new Comparator<Session>() {
// Goal: Keep the connection with the lowest port number
///
// Low vs high is not very significant. The critical
// part is that they both choose the same connection.
//
// Port numbers are seen on both sides. There are two
// ports (one client and one server) for each connection.
//
// Both sides will agree to kill the connection with the
// lowest server port. If those are the same, then both
// sides will agree to kill the connection with the lowest
// client port. If those are the same, we still close a
// connection and hope for the best. If both connections
// are killed we will try again next time another node
// lists the server and we notice we are not connected.
//
@Override
public int compare(final Session a, final Session b) {
final int serverRank = server(a) - server(b);
if (serverRank != 0)
return serverRank;
return client(a) - client(b);
}
private int server(final Session a) {
final Socket socket = a.channel.socket();
return a.client ? socket.getPort() : socket.getLocalPort();
}
private int client(final Session a) {
final Socket socket = a.channel.socket();
return !a.client ? socket.getPort() : socket.getLocalPort();
}
});
}
session = sessions[0];
duplicate = sessions[1];
session.trace(session + "@" + session.hashCode() + " KEEP");
duplicate.trace(duplicate + "@" + duplicate.hashCode() + " KILL");
duplicate.hangup = true;
}
if (session.state == State.GREETING) {
session.info(session + "@" + session.hashCode() + " DISCOVERED");
}
connections.put(session.uri, session);
}
}
private void println(final String s) {
// if (debug && s.matches(".*(Listening|DONE|KEEP|KILL)")) {
// System.out.format("%1$tH:%1$tM:%1$tS.%1$tL - %2$s\n", System.currentTimeMillis(), s);
// }
}
@Override
public String toString() {
return "MultipointServer{" +
"name='" + name + '\'' +
", me=" + me +
'}';
}
public static String randomColor() {
final String[] colors = {
"almond",
"amber",
"amethyst",
"apple",
"apricot",
"aqua",
"aquamarine",
"ash",
"azure",
"banana",
"beige",
"black",
"blue",
"brick",
"bronze",
"brown",
"burgundy",
"carrot",
"charcoal",
"cherry",
"chestnut",
"chocolate",
"chrome",
"cinnamon",
"citrine",
"cobalt",
"copper",
"coral",
"cornflower",
"cotton",
"cream",
"crimson",
"cyan",
"ebony",
"emerald",
"forest",
"fuchsia",
"ginger",
"gold",
"goldenrod",
"gray",
"green",
"grey",
"indigo",
"ivory",
"jade",
"jasmine",
"khaki",
"lava",
"lavender",
"lemon",
"lilac",
"lime",
"macaroni",
"magenta",
"magnolia",
"mahogany",
"malachite",
"mango",
"maroon",
"mauve",
"mint",
"moonstone",
"navy",
"ocean",
"olive",
"onyx",
"orange",
"orchid",
"papaya",
"peach",
"pear",
"pearl",
"periwinkle",
"pine",
"pink",
"pistachio",
"platinum",
"plum",
"prune",
"pumpkin",
"purple",
"quartz",
"raspberry",
"red",
"rose",
"rosewood",
"ruby",
"salmon",
"sapphire",
"scarlet",
"sienna",
"silver",
"slate",
"strawberry",
"tan",
"tangerine",
"taupe",
"teal",
"titanium",
"topaz",
"turquoise",
"umber",
"vanilla",
"violet",
"watermelon",
"white",
"yellow"
};
final Random random = new Random();
long l = random.nextLong();
if (l < 0)
l *= -1;
final long index = l % colors.length;
return colors[(int) index];
}
private final Executor dnsResolutionQueue = Executors.newFixedThreadPool(2, new DaemonThreadFactory("multipoint-server-"));
private class Host {
private final URI uri;
private final FutureTask<InetAddress> address;
private Host(final URI uri) {
this.uri = uri;
this.address = new FutureTask<InetAddress>(new Callable<InetAddress>() {
@Override
public InetAddress call() throws Exception {
return InetAddress.getByName(Host.this.uri.getHost());
}
});
}
public void resolveDns() {
dnsResolutionQueue.execute(address);
}
public boolean isDone() {
return address.isDone();
}
public InetSocketAddress getSocketAddress() throws ExecutionException, TimeoutException {
try {
final InetAddress inetAddress = address.get(0, TimeUnit.NANOSECONDS);
return new InetSocketAddress(inetAddress, uri.getPort());
} catch (final InterruptedException e) {
Thread.interrupted();
throw new TimeoutException();
}
}
public URI getUri() {
return uri;
}
@Override
public boolean equals(final Object o) {
if (this == o)
return true;
if (o == null || getClass() != o.getClass())
return false;
final Host host = (Host) o;
return uri.equals(host.uri);
}
@Override
public int hashCode() {
return uri.hashCode();
}
}
}