/**
* 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 com.google.devcoin.examples;
import com.google.devcoin.core.*;
import com.google.devcoin.crypto.KeyCrypterException;
import com.google.devcoin.kits.WalletAppKit;
import com.google.devcoin.params.MainNetParams;
import com.google.devcoin.params.RegTestParams;
import com.google.devcoin.params.TestNet3Params;
import com.google.devcoin.utils.BriefLogFormatter;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.MoreExecutors;
import java.io.File;
import java.math.BigInteger;
import static com.google.common.base.Preconditions.checkNotNull;
/**
* ForwardingService demonstrates basic usage of the library. It sits on the network and when it receives coins, simply
* sends them onwards to an address given on the command line.
*/
public class ForwardingService {
private static Address forwardingAddress;
private static WalletAppKit kit;
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();
if (args.length < 2) {
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;
String filePrefix;
if (args[1].equals("testnet")) {
params = TestNet3Params.get();
filePrefix = "forwarding-service-testnet";
} else if (args[1].equals("regtest")) {
params = RegTestParams.get();
filePrefix = "forwarding-service-regtest";
} else {
params = MainNetParams.get();
filePrefix = "forwarding-service";
}
// Parse the address given as the first parameter.
forwardingAddress = new Address(params, args[0]);
// Start up a basic app using a class that automates some boilerplate. Ensure we always have at least one key.
kit = new WalletAppKit(params, new File("."), filePrefix) {
@Override
protected void onSetupCompleted() {
// This is called in a background thread after startAndWait is called, as setting up various objects
// can do disk and network IO that may cause UI jank/stuttering in wallet apps if it were to be done
// on the main thread.
if (wallet().getKeychainSize() < 1)
wallet().addKey(new ECKey());
}
};
if (params == RegTestParams.get()) {
// Regression test mode is designed for testing and development only, so there's no public network for it.
// If you pick this mode, you're expected to be running a local "bitcoind -regtest" instance.
kit.connectToLocalHost();
}
// Download the block chain and wait until it's done.
kit.startAndWait();
// We want to know when we receive money.
kit.wallet().addEventListener(new AbstractWalletEventListener() {
@Override
public void onCoinsReceived(Wallet w, Transaction tx, BigInteger prevBalance, BigInteger 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).
BigInteger value = tx.getValueSentToMe(w);
System.out.println("Received tx for " + Utils.bitcoinValueToFriendlyString(value) + ": " + 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().getKeys().get(0).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) {}
}
private static void forwardCoins(Transaction tx) {
try {
BigInteger value = tx.getValueSentToMe(kit.wallet());
System.out.println("Forwarding " + Utils.bitcoinValueToFriendlyString(value) + " BTC");
// Now send the coins back! Send with a small fee attached to ensure rapid confirmation.
final BigInteger amountToSend = value.subtract(Transaction.REFERENCE_DEFAULT_MIN_TX_FEE);
final Wallet.SendResult sendResult = kit.wallet().sendCoins(kit.peerGroup(), forwardingAddress, amountToSend);
checkNotNull(sendResult); // We should never try to send more coins than we have!
System.out.println("Sending ...");
// Register a callback that is invoked when the transaction has propagated across the network.
// This shows a second style of registering ListenableFuture callbacks, it works when you don't
// need access to the object the future returns.
sendResult.broadcastComplete.addListener(new Runnable() {
@Override
public void run() {
// The wallet has changed now, it'll get auto saved shortly or when the app shuts down.
System.out.println("Sent coins onwards! Transaction hash is " + sendResult.tx.getHashAsString());
}
}, MoreExecutors.sameThreadExecutor());
} catch (KeyCrypterException e) {
// We don't use encrypted wallets in this example - can never happen.
throw new RuntimeException(e);
}
}
}