/*
 * 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 java.io.File;
import java.math.BigInteger;
import java.net.InetAddress;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

/**
 * RefreshWallet loads a wallet, then processes the block chain to update the transaction pools within it.
 */
public class RefreshWallet {
    public static void main(String[] args) throws Exception {
        File file = new File(args[0]);
        Wallet wallet = Wallet.loadFromFile(file);
        System.out.println(wallet.toString());

        // Set up the components and link them together.
        final NetworkParameters params = NetworkParameters.testNet();
        BlockStore blockStore = new MemoryBlockStore(params);
        NetworkConnection conn = new NetworkConnection(InetAddress.getLocalHost(), params,
                                                       blockStore.getChainHead().getHeight(), 60000);
        BlockChain chain = new BlockChain(params, wallet, blockStore);
        Peer peer = new Peer(params, conn, chain);
        peer.start();

        wallet.addEventListener(new WalletEventListener() {
            public void onCoinsReceived(Wallet w, Transaction tx, BigInteger prevBalance, BigInteger newBalance) {
                System.out.println("\nReceived tx " + tx.getHashAsString());
                System.out.println(tx.toString());
            }
        });

        // Now download and process the block chain.
        CountDownLatch progress = peer.startBlockChainDownload();
        long max = progress.getCount();  // Racy but no big deal.
        if (max > 0) {
            System.out.println("Downloading block chain. " + (max > 1000 ? "This may take a while." : ""));
            long current = max;
            while (current > 0) {
                double pct = 100.0 - (100.0 * (current / (double) max));
                System.out.println(String.format("Chain download %d%% done", (int) pct));
                progress.await(1, TimeUnit.SECONDS);
                current = progress.getCount();
            }
        }
        peer.disconnect();
        wallet.saveToFile(file);
        System.out.println("\nDone!\n");
        System.out.println(wallet.toString());
    }
}

Add a program that just loads a wallet, runs through the block chain, and then saves/prints out the resulting wallet at the end.