List of usage examples for com.google.common.util.concurrent FutureCallback FutureCallback
FutureCallback
From source file:com.metamx.rdiclient.example.FileInputMain.java
public static void main(String[] args) throws Exception { if (args.length == 0) { System.err.println(String.format("Usage: %s file1 file2 ...", FileInputMain.class.getCanonicalName())); System.exit(1);/*w ww . j a v a2 s .c om*/ } // Start up RdiClient. final RdiClientConfig rdiConfig = RdiClientConfig.fromProperties(Props.fromFilename("conf/rdi.properties")); final RdiClient<byte[]> rdiClient = RdiClients.usingPassthroughSerializer(rdiConfig); rdiClient.start(); // Track how many messages are sent and how many successes and failures are received. final AtomicLong sends = new AtomicLong(0); final AtomicLong acks = new AtomicLong(0); final AtomicLong fails = new AtomicLong(0); // Send data from files (in args) through RdiClient. for (final String arg : args) { final File file = new File(arg); try (final BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream(file)))) { String line; while ((line = in.readLine()) != null) { // Asynchronously send a message. final ListenableFuture<RdiResponse> send = rdiClient.send(line.getBytes(Charsets.UTF_8)); sends.incrementAndGet(); // When the message is acknowledged (or fails), increment the appropriate counter. Futures.addCallback(send, new FutureCallback<RdiResponse>() { @Override public void onSuccess(RdiResponse result) { acks.incrementAndGet(); } @Override public void onFailure(Throwable t) { fails.incrementAndGet(); } }); } } } // Done sending messages. rdiClient.flush(); // Wait for all messages to be sent. while (sends.get() != acks.get() + fails.get()) { Thread.sleep(100); } // Close the client. rdiClient.close(); // Log and exit. log.info("Sent %,d messages with %,d acks and %,d fails.", sends.get(), acks.get(), fails.get()); }
From source file:com.amazonaws.services.kinesis.producer.sample.MetricsAwareSampleProducer.java
public static void main(String[] args) throws InterruptedException, ExecutionException { final long totalRecordsToPut = 50000; final int dataSize = 64; final long outstandingLimit = 5000; final AtomicLong sequenceNumber = new AtomicLong(0); final AtomicLong completed = new AtomicLong(0); final String timetstamp = Long.toString(System.currentTimeMillis()); KinesisProducerConfiguration config = new KinesisProducerConfiguration().setRecordMaxBufferedTime(3000) .setMaxConnections(1).setRequestTimeout(60000).setRegion(SampleProducer.REGION); final KinesisProducer kinesisProducer = new KinesisProducer(config); // Result handler final FutureCallback<UserRecordResult> callback = new FutureCallback<UserRecordResult>() { @Override// ww w.ja v a2 s. co m public void onFailure(Throwable t) { if (t instanceof UserRecordFailedException) { Attempt last = Iterables.getLast(((UserRecordFailedException) t).getResult().getAttempts()); log.error(String.format("Record failed to put - %s : %s", last.getErrorCode(), last.getErrorMessage())); } log.error("Exception during put", t); System.exit(1); } @Override public void onSuccess(UserRecordResult result) { completed.getAndIncrement(); } }; // Progress updates Thread progress = new Thread(new Runnable() { @Override public void run() { while (true) { long put = sequenceNumber.get(); double putPercent = 100.0 * put / totalRecordsToPut; long done = completed.get(); double donePercent = 100.0 * done / totalRecordsToPut; log.info(String.format("Put %d of %d so far (%.2f %%), %d have completed (%.2f %%)", put, totalRecordsToPut, putPercent, done, donePercent)); if (done == totalRecordsToPut) { break; } // Numerous metrics are available from the KPL locally, as // well as uploaded to CloudWatch. See the metrics // documentation for details. // // KinesisProducer provides methods to retrieve metrics for // the current instance, with a customizable time window. // This allows us to get sliding window statistics in real // time for the current host. // // Here we're going to look at the number of user records // put over a 5 seconds sliding window. try { for (Metric m : kinesisProducer.getMetrics("UserRecordsPut", 5)) { // Metrics are emitted at different granularities, here // we only look at the stream level metric, which has a // single dimension of stream name. if (m.getDimensions().size() == 1 && m.getSampleCount() > 0) { log.info(String.format( "(Sliding 5 seconds) Avg put rate: %.2f per sec, success rate: %.2f, failure rate: %.2f, total attemped: %d", m.getSum() / 5, m.getSum() / m.getSampleCount() * 100, (m.getSampleCount() - m.getSum()) / m.getSampleCount() * 100, (long) m.getSampleCount())); } } } catch (Exception e) { log.error("Unexpected error getting metrics", e); System.exit(1); } try { Thread.sleep(1000); } catch (InterruptedException e) { } } } }); progress.start(); // Put records while (true) { // We're going to put as fast as we can until we've reached the max // number of records outstanding. if (sequenceNumber.get() < totalRecordsToPut) { if (kinesisProducer.getOutstandingRecordsCount() < outstandingLimit) { ByteBuffer data = Utils.generateData(sequenceNumber.incrementAndGet(), dataSize); ListenableFuture<UserRecordResult> f = kinesisProducer.addUserRecord(SampleProducer.STREAM_NAME, timetstamp, data); Futures.addCallback(f, callback); } else { Thread.sleep(1); } } else { break; } } // Wait for remaining records to finish while (kinesisProducer.getOutstandingRecordsCount() > 0) { kinesisProducer.flush(); Thread.sleep(100); } progress.join(); for (Metric m : kinesisProducer.getMetrics("UserRecordsPerKinesisRecord")) { if (m.getDimensions().containsKey("ShardId")) { log.info(String.format( "%.2f user records were aggregated into each Kinesis record on average for shard %s, for a total of %d Kinesis records.", m.getMean(), m.getDimensions().get("ShardId"), (long) m.getSampleCount())); } } kinesisProducer.destroy(); log.info("Finished."); }
From source file:com.google.NithPoints.examples.PrintPeers.java
public static void main(String[] args) throws Exception { BriefLogFormatter.init();/*from w w w. j ava 2 s . c o m*/ System.out.println("=== DNS ==="); printDNS(); System.out.println("=== Version/chain heights ==="); ArrayList<InetAddress> addrs = new ArrayList<InetAddress>(); for (InetSocketAddress peer : dnsPeers) addrs.add(peer.getAddress()); System.out.println("Scanning " + addrs.size() + " peers:"); final NetworkParameters params = NetworkParameters.prodNet(); final Object lock = new Object(); final long[] bestHeight = new long[1]; List<ListenableFuture<TCPNetworkConnection>> futures = Lists.newArrayList(); for (final InetAddress addr : addrs) { final ListenableFuture<TCPNetworkConnection> future = TCPNetworkConnection.connectTo(params, new InetSocketAddress(addr, params.port), 1000 /* timeout */); futures.add(future); // Once the connection has completed version handshaking ... Futures.addCallback(future, new FutureCallback<TCPNetworkConnection>() { public void onSuccess(TCPNetworkConnection conn) { // Check the chain height it claims to have. VersionMessage ver = conn.getVersionMessage(); long nodeHeight = ver.bestHeight; synchronized (lock) { long diff = bestHeight[0] - nodeHeight; if (diff > 0) { System.out.println("Node is behind by " + diff + " blocks: " + addr); } else if (diff == 0) { System.out.println("Node " + addr + " has " + nodeHeight + " blocks"); bestHeight[0] = nodeHeight; } else if (diff < 0) { System.out.println("Node is ahead by " + Math.abs(diff) + " blocks: " + addr); bestHeight[0] = nodeHeight; } } conn.close(); } public void onFailure(Throwable throwable) { System.out.println("Failed to talk to " + addr + ": " + throwable.getMessage()); } }); } // Wait for every tried connection to finish. Futures.successfulAsList(futures).get(); }
From source file:com.google.logicoin.examples.PrintPeers.java
public static void main(String[] args) throws Exception { BriefLogFormatter.init();/* w w w . j a v a 2 s . c om*/ System.out.println("=== DNS ==="); printDNS(); System.out.println("=== Version/chain heights ==="); ArrayList<InetAddress> addrs = new ArrayList<InetAddress>(); for (InetSocketAddress peer : dnsPeers) addrs.add(peer.getAddress()); System.out.println("Scanning " + addrs.size() + " peers:"); final NetworkParameters params = MainNetParams.get(); final Object lock = new Object(); final long[] bestHeight = new long[1]; List<ListenableFuture<TCPNetworkConnection>> futures = Lists.newArrayList(); for (final InetAddress addr : addrs) { final ListenableFuture<TCPNetworkConnection> future = TCPNetworkConnection.connectTo(params, new InetSocketAddress(addr, params.getPort()), 1000 /* timeout */, null); futures.add(future); // Once the connection has completed version handshaking ... Futures.addCallback(future, new FutureCallback<TCPNetworkConnection>() { public void onSuccess(TCPNetworkConnection conn) { // Check the chain height it claims to have. VersionMessage ver = conn.getVersionMessage(); long nodeHeight = ver.bestHeight; synchronized (lock) { long diff = bestHeight[0] - nodeHeight; if (diff > 0) { System.out.println("Node is behind by " + diff + " blocks: " + addr); } else if (diff == 0) { System.out.println("Node " + addr + " has " + nodeHeight + " blocks"); bestHeight[0] = nodeHeight; } else if (diff < 0) { System.out.println("Node is ahead by " + Math.abs(diff) + " blocks: " + addr); bestHeight[0] = nodeHeight; } } conn.close(); } public void onFailure(Throwable throwable) { System.out.println("Failed to talk to " + addr + ": " + throwable.getMessage()); } }); } // Wait for every tried connection to finish. Futures.successfulAsList(futures).get(); }
From source file:org.bitcoinj.examples.StakingService.java
public static void main(String[] args) throws Exception { // This line makes the log output more compact and easily read, especially when using the JDK log adapter. BriefLogFormatter.init();/* w w w . j a v a 2 s . c o m*/ // Figure out which network we should connect to. Each one gets its own set of files. final NetworkParameters params; String filePrefix; params = MainNetParams.get(); filePrefix = "forwarding-service"; kit = new WalletAppKit(params, new File("."), filePrefix); //TODO Remove kit.connectToLocalHost(); // Download the block chain and wait until it's done. kit.startAsync(); kit.awaitRunning(); // We want to know when we receive money. kit.wallet().addEventListener(new AbstractWalletEventListener() { @Override public void onCoinsReceived(Wallet w, Transaction tx, Coin prevBalance, Coin newBalance) { // Runs in the dedicated "user thread" (see bitcoinj docs for more info on this). // // The transaction "tx" can either be pending, or included into a block (we didn't see the broadcast). Coin value = tx.getValueSentToMe(w); System.out.println("Received tx for " + value.toFriendlyString() + ": " + tx); System.out.println("Transaction will be forwarded after it confirms."); // Wait until it's made it into the block chain (may run immediately if it's already there). // // For this dummy app of course, we could just forward the unconfirmed transaction. If it were // to be double spent, no harm done. Wallet.allowSpendingUnconfirmedTransactions() would have to // be called in onSetupCompleted() above. But we don't do that here to demonstrate the more common // case of waiting for a block. Futures.addCallback(tx.getConfidence().getDepthFuture(1), new FutureCallback<TransactionConfidence>() { @Override public void onSuccess(TransactionConfidence result) { System.out.println("got it, printing private keys for importprivkey"); List<ECKey> issuedReceiveKeys = kit.wallet().getIssuedReceiveKeys(); for (ECKey code : issuedReceiveKeys) { System.out.println( "private keys:" + code.getPrivateKeyEncoded(params).toString()); } //stakeCoins(params, kit.peerGroup(),kit.wallet(),kit.store(),kit.chain()); } @Override public void onFailure(Throwable t) { // This kind of future can't fail, just rethrow in case something weird happens. throw new RuntimeException(t); } }); } }); Address sendToAddress = kit.wallet().currentReceiveKey().toAddress(params); System.out.println("Send coins to: " + sendToAddress); List<ECKey> issuedReceiveKeys = kit.wallet().getIssuedReceiveKeys(); for (ECKey code : issuedReceiveKeys) { System.out.println("private keys:" + code.getPrivateKeyEncoded(params).toString()); } System.out.println("staking.."); List<TransactionOutput> calculateAllSpendCandidates = kit.wallet().calculateAllSpendCandidates(); for (TransactionOutput coin : calculateAllSpendCandidates) { System.out.println("coins:" + coin.getValue()); } stakeCoins(params, kit.peerGroup(), kit.wallet(), kit.store(), kit.chain()); }
From source file:org.bitcoinj.examples.SendRequest.java
public static void main(String[] args) throws Exception { // We use the WalletAppKit that handles all the boilerplate for us. Have a look at the Kit.java example for more details. NetworkParameters params = TestNet3Params.get(); WalletAppKit kit = new WalletAppKit(params, new File("."), "sendrequest-example"); kit.startAsync();//from w w w.j a v a2s. com kit.awaitRunning(); // How much coins do we want to send? // The Coin class represents a monetary Bitcoin value. // We use the parseCoin function to simply get a Coin instance from a simple String. Coin value = Coin.parseCoin("0.09"); // To which address you want to send the coins? // The Address class represents a Bitcoin address. Address to = Address.fromBase58(params, "mupBAFeT63hXfeeT4rnAUcpKHDkz1n4fdw"); System.out.println("Send money to: " + to.toString()); // There are different ways to create and publish a SendRequest. This is probably the easiest one. // Have a look at the code of the SendRequest class to see what's happening and what other options you have: https://bitcoinj.github.io/javadoc/0.11/com/google/bitcoin/core/Wallet.SendRequest.html // // Please note that this might raise a InsufficientMoneyException if your wallet has not enough coins to spend. // When using the testnet you can use a faucet (like the http://faucet.xeno-genesis.com/) to get testnet coins. // In this example we catch the InsufficientMoneyException and register a BalanceFuture callback that runs once the wallet has enough balance. try { Wallet.SendResult result = kit.wallet().sendCoins(kit.peerGroup(), to, value); System.out.println("coins sent. transaction hash: " + result.tx.getHashAsString()); // you can use a block explorer like https://www.biteasy.com/ to inspect the transaction with the printed transaction hash. } catch (InsufficientMoneyException e) { System.out.println("Not enough coins in your wallet. Missing " + e.missing.getValue() + " satoshis are missing (including fees)"); System.out.println("Send money to: " + kit.wallet().currentReceiveAddress().toString()); // Bitcoinj allows you to define a BalanceFuture to execute a callback once your wallet has a certain balance. // Here we wait until the we have enough balance and display a notice. // Bitcoinj is using the ListenableFutures of the Guava library. Have a look here for more information: https://github.com/google/guava/wiki/ListenableFutureExplained ListenableFuture<Coin> balanceFuture = kit.wallet().getBalanceFuture(value, BalanceType.AVAILABLE); FutureCallback<Coin> callback = new FutureCallback<Coin>() { @Override public void onSuccess(Coin balance) { System.out.println("coins arrived and the wallet now has enough balance"); } @Override public void onFailure(Throwable t) { System.out.println("something went wrong"); } }; Futures.addCallback(balanceFuture, callback); } // shutting down //kit.stopAsync(); //kit.awaitTerminated(); }
From source file:org.guldenj.examples.SendRequest.java
public static void main(String[] args) throws Exception { // We use the WalletAppKit that handles all the boilerplate for us. Have a look at the Kit.java example for more details. NetworkParameters params = TestNet3Params.get(); WalletAppKit kit = new WalletAppKit(params, new File("."), "sendrequest-example"); kit.startAsync();/* w w w .jav a 2s.c o m*/ kit.awaitRunning(); System.out.println("Send money to: " + kit.wallet().currentReceiveAddress().toString()); // How much coins do we want to send? // The Coin class represents a monetary Bitcoin value. // We use the parseCoin function to simply get a Coin instance from a simple String. Coin value = Coin.parseCoin("0.09"); // To which address you want to send the coins? // The Address class represents a Bitcoin address. Address to = Address.fromBase58(params, "mupBAFeT63hXfeeT4rnAUcpKHDkz1n4fdw"); // There are different ways to create and publish a SendRequest. This is probably the easiest one. // Have a look at the code of the SendRequest class to see what's happening and what other options you have: https://guldenj.github.io/javadoc/0.11/com/google/bitcoin/core/Wallet.SendRequest.html // // Please note that this might raise a InsufficientMoneyException if your wallet has not enough coins to spend. // When using the testnet you can use a faucet (like the http://faucet.xeno-genesis.com/) to get testnet coins. // In this example we catch the InsufficientMoneyException and register a BalanceFuture callback that runs once the wallet has enough balance. try { Wallet.SendResult result = kit.wallet().sendCoins(kit.peerGroup(), to, value); System.out.println("coins sent. transaction hash: " + result.tx.getHashAsString()); // you can use a block explorer like https://www.biteasy.com/ to inspect the transaction with the printed transaction hash. } catch (InsufficientMoneyException e) { System.out.println("Not enough coins in your wallet. Missing " + e.missing.getValue() + " satoshis are missing (including fees)"); System.out.println("Send money to: " + kit.wallet().currentReceiveAddress().toString()); // Bitcoinj allows you to define a BalanceFuture to execute a callback once your wallet has a certain balance. // Here we wait until the we have enough balance and display a notice. // Bitcoinj is using the ListenableFutures of the Guava library. Have a look here for more information: https://github.com/google/guava/wiki/ListenableFutureExplained ListenableFuture<Coin> balanceFuture = kit.wallet().getBalanceFuture(value, BalanceType.AVAILABLE); FutureCallback<Coin> callback = new FutureCallback<Coin>() { @Override public void onSuccess(Coin balance) { System.out.println("coins arrived and the wallet now has enough balance"); } @Override public void onFailure(Throwable t) { System.out.println("something went wrong"); } }; Futures.addCallback(balanceFuture, callback); } // shutting down //kit.stopAsync(); //kit.awaitTerminated(); }
From source file:org.litecoinj.examples.SendRequest.java
public static void main(String[] args) throws Exception { // We use the WalletAppKit that handles all the boilerplate for us. Have a look at the Kit.java example for more details. NetworkParameters params = TestNet3Params.get(); WalletAppKit kit = new WalletAppKit(params, new File("."), "sendrequest-example"); kit.startAsync();/*from ww w . ja v a 2 s . co m*/ kit.awaitRunning(); System.out.println("Send money to: " + kit.wallet().currentReceiveAddress().toString()); // How much coins do we want to send? // The Coin class represents a monetary Bitcoin value. // We use the parseCoin function to simply get a Coin instance from a simple String. Coin value = Coin.parseCoin("0.09"); // To which address you want to send the coins? // The Address class represents a Bitcoin address. Address to = Address.fromBase58(params, "mupBAFeT63hXfeeT4rnAUcpKHDkz1n4fdw"); // There are different ways to create and publish a SendRequest. This is probably the easiest one. // Have a look at the code of the SendRequest class to see what's happening and what other options you have: https://bitcoinj.github.io/javadoc/0.11/com/google/bitcoin/core/Wallet.SendRequest.html // // Please note that this might raise a InsufficientMoneyException if your wallet has not enough coins to spend. // When using the testnet you can use a faucet (like the http://faucet.xeno-genesis.com/) to get testnet coins. // In this example we catch the InsufficientMoneyException and register a BalanceFuture callback that runs once the wallet has enough balance. try { Wallet.SendResult result = kit.wallet().sendCoins(kit.peerGroup(), to, value); System.out.println("coins sent. transaction hash: " + result.tx.getHashAsString()); // you can use a block explorer like https://www.biteasy.com/ to inspect the transaction with the printed transaction hash. } catch (InsufficientMoneyException e) { System.out.println("Not enough coins in your wallet. Missing " + e.missing.getValue() + " satoshis are missing (including fees)"); System.out.println("Send money to: " + kit.wallet().currentReceiveAddress().toString()); // Bitcoinj allows you to define a BalanceFuture to execute a callback once your wallet has a certain balance. // Here we wait until the we have enough balance and display a notice. // Bitcoinj is using the ListenableFutures of the Guava library. Have a look here for more information: https://github.com/google/guava/wiki/ListenableFutureExplained ListenableFuture<Coin> balanceFuture = kit.wallet().getBalanceFuture(value, BalanceType.AVAILABLE); FutureCallback<Coin> callback = new FutureCallback<Coin>() { @Override public void onSuccess(Coin balance) { System.out.println("coins arrived and the wallet now has enough balance"); } @Override public void onFailure(Throwable t) { System.out.println("something went wrong"); } }; Futures.addCallback(balanceFuture, callback); } // shutting down //kit.stopAsync(); //kit.awaitTerminated(); }
From source file:io.xpydev.paycoinj.examples.ForwardingService.java
public static void main(String[] args) throws Exception { // This line makes the log output more compact and easily read, especially when using the JDK log adapter. BriefLogFormatter.initVerbose();/*from ww w . j ava 2 s.c om*/ // if (args.length < 1) { // System.err.println("Usage: address-to-send-back-to [regtest|testnet]"); // return; // } // Figure out which network we should connect to. Each one gets its own set of files. NetworkParameters params = MainNetParams.get(); String filePrefix = "forwarding-service"; // Parse the address given as the first parameter. forwardingAddress = new Address(params, "PS43Jt2x3LXCkou2hZPaKjGwb1TQmAaihg"); // Start up a basic app using a class that automates some boilerplate. kit = new WalletAppKit(params, new File("."), filePrefix); // Download the block chain and wait until it's done. kit.startAsync(); kit.setBlockingStartup(false); kit.awaitRunning(); // kit.peerGroup().addPeerDiscovery(new SeedPeers(params), true); kit.peerGroup().setFastCatchupTimeSecs(1417219190L); // We want to know when we receive money. kit.wallet().addEventListener(new AbstractWalletEventListener() { @Override public void onCoinsReceived(Wallet w, Transaction tx, Coin prevBalance, Coin newBalance) { // Runs in the dedicated "user thread" (see peercoinj docs for more info on this). // // The transaction "tx" can either be pending, or included into a block (we didn't see the broadcast). Coin value = tx.getValueSentToMe(w); System.out.println("Received tx for " + value.toFriendlyString() + ": " + tx); System.out.println("Transaction will be forwarded after it confirms."); // Wait until it's made it into the block chain (may run immediately if it's already there). // // For this dummy app of course, we could just forward the unconfirmed transaction. If it were // to be double spent, no harm done. Wallet.allowSpendingUnconfirmedTransactions() would have to // be called in onSetupCompleted() above. But we don't do that here to demonstrate the more common // case of waiting for a block. Futures.addCallback(tx.getConfidence().getDepthFuture(1), new FutureCallback<Transaction>() { @Override public void onSuccess(Transaction result) { // "result" here is the same as "tx" above, but we use it anyway for clarity. forwardCoins(result); } @Override public void onFailure(Throwable t) { // This kind of future can't fail, just rethrow in case something weird happens. throw new RuntimeException(t); } }); } }); Address sendToAddress = kit.wallet().currentReceiveKey().toAddress(params); System.out.println("Send coins to: " + sendToAddress); System.out.println("Waiting for coins to arrive. Press Ctrl-C to quit."); try { Thread.sleep(Long.MAX_VALUE); } catch (InterruptedException ignored) { } }
From source file:com.google.litecoin.examples.PrintPeers.java
public static void main(String[] args) throws Exception { BriefLogFormatter.init();/*from w w w. j a va2 s.c o m*/ System.out.println("=== IRC ==="); printIRC(); System.out.println("=== DNS ==="); printDNS(); System.out.println("=== Version/chain heights ==="); ArrayList<InetAddress> addrs = new ArrayList<InetAddress>(); for (InetSocketAddress peer : dnsPeers) addrs.add(peer.getAddress()); for (InetSocketAddress peer : ircPeers) addrs.add(peer.getAddress()); System.out.println("Scanning " + addrs.size() + " peers:"); final NetworkParameters params = NetworkParameters.prodNet(); final Object lock = new Object(); final long[] bestHeight = new long[1]; List<ListenableFuture<TCPNetworkConnection>> futures = Lists.newArrayList(); for (final InetAddress addr : addrs) { final ListenableFuture<TCPNetworkConnection> future = TCPNetworkConnection.connectTo(params, new InetSocketAddress(addr, params.port), 1000 /* timeout */); futures.add(future); // Once the connection has completed version handshaking ... Futures.addCallback(future, new FutureCallback<TCPNetworkConnection>() { public void onSuccess(TCPNetworkConnection conn) { // Check the chain height it claims to have. VersionMessage ver = conn.getVersionMessage(); long nodeHeight = ver.bestHeight; synchronized (lock) { long diff = bestHeight[0] - nodeHeight; if (diff > 0) { System.out.println("Node is behind by " + diff + " blocks: " + addr); } else if (diff == 0) { System.out.println("Node " + addr + " has " + nodeHeight + " blocks"); bestHeight[0] = nodeHeight; } else if (diff < 0) { System.out.println("Node is ahead by " + Math.abs(diff) + " blocks: " + addr); bestHeight[0] = nodeHeight; } } conn.close(); } public void onFailure(Throwable throwable) { System.out.println("Failed to talk to " + addr + ": " + throwable.getMessage()); } }); } // Wait for every tried connection to finish. Futures.successfulAsList(futures).get(); }