altcoinj/src/com/google/bitcoin/examples/FetchBlock.java

/*
 * Copyright 2011 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.bitcoin.examples;

import com.google.bitcoin.core.*;
import com.google.bitcoin.store.BlockStore;
import com.google.bitcoin.store.MemoryBlockStore;

import java.net.InetAddress;
import java.util.concurrent.Future;

/**
 * Downloads the block given a block hash from the localhost node and prints it out.
 */
public class FetchBlock {
    public static void main(String[] args) throws Exception {
        System.out.println("Connecting to node");
        final NetworkParameters params = NetworkParameters.prodNet();

        BlockStore blockStore = new MemoryBlockStore(params);
        BlockChain chain = new BlockChain(params, blockStore);
        final Peer peer = new Peer(params, new PeerAddress(InetAddress.getLocalHost()), chain);
        peer.connect();
        new Thread(new Runnable() {
            public void run() {
                try {
                    peer.run();
                } catch (PeerException e) {
                    throw new RuntimeException(e);
                }
            }
        }).start();

        Sha256Hash blockHash = new Sha256Hash(args[0]);
        Future<Block> future = peer.getBlock(blockHash);
        System.out.println("Waiting for node to send us the requested block: " + blockHash);
        Block block = future.get();
        System.out.println(block);
        peer.disconnect();
    }
}