kswang

event Log(string msg, uint value);
function sendCoin(address receiver, uint amount) public returns(bool sufficient) {
    if (balances[msg.sender] < amount) return false;
    emit Log("step 1", amount);
    balances[msg.sender] -= amount;
    emit Log("step 2", amount);
    balances[receiver] += amount;
    emit Log("step 3", amount);
    emit Transfer(msg.sender, receiver, amount);
    return true;

kswang

pragma solidity ^1.4.18;
 
import "./ConvertLib.sol";
 
// This is just a simple example of a coin-like contract.
// It is not standards compatible and cannot be expected to talk to other
// coin/token contracts. If you want to create a standards-compliant
// token, see: https://github.com/ConsenSys/Tokens. Cheers!
 
contract MetaCoin {

kswang

const MetaCoin = artifacts.require("MetaCoin");
 
contract('2nd MetaCoin test', async (accounts) => {
 
  it("should put 10000 MetaCoin in the first account", async () => {
     let instance = await MetaCoin.deployed();
     let balance = await instance.getBalance.call(accounts[0]);
     assert.equal(balance.valueOf(), 10000);
  })
 

kswang

var MetaCoin = artifacts.require("./MetaCoin.sol");
 
contract('MetaCoin', function(accounts) {
  it("should put 10000 MetaCoin in the first account", function() {
    return MetaCoin.deployed().then(function(instance) {
      return instance.getBalance.call(accounts[0]);
    }).then(function(balance) {
      assert.equal(balance.valueOf(), 10000, "10000 wasn't in the first account");
    });
  });

kswang

Observable<Transaction> myCatchUpToLatestAndSubscribeToNewTransactionsObservable(
  DefaultBlockParameter startBlock) {


  return web3j.catchUpToLatestAndSubscribeToNewBlocksObservable(startBlock, false)
    .flatMap(currentBlock -> {
      BigInteger confirmedBlock = currentBlock.getBlock().getNumber().subtract(confirmationBlock);
      return web3j.ethGetBlockByNumber(DefaultBlockParameter.valueOf(confirmedBlock), true).observable();
    }).flatMapIterable(MyWeb3j::toTransactions);
}

kswang

// Main.java
public void subscribe() {
    Web3j web3j = Web3j.build(new HttpService("http://123.123.123:8545")); // your ethereum clinet
    List<Handler> handlers = Lists.newArrayList(new OwnershipTransferredEventHandler());  // init all the handler objects
    String[] topics = handlers.stream().map(Handler::getTopic).toArray(String[]::new);
 
 
    EthFilter filter = new EthFilter(startBlock, DefaultBlockParameterName.LATEST, contractAddress);
    filter.addOptionalTopics(topics);
    Subscription subscription = web3j.ethLogObservable(filter)

kswang

public class MyContract extends Contract {
    private static final String BINARY = "";
 
    public static final Event OWNERSHIPTRANSFERRED_EVENT = new Event("OwnershipTransferred",
            Arrays.<TypeReference<?>>asList(new TypeReference<Address>(true) {}, new TypeReference<Address>(true) {}));
 
    public Observable<OwnershipTransferredEventResponse> ownershipTransferredEventObservable(EthFilter filter) {
        return web3j.ethLogObservable(filter).map(new Func1<Log, OwnershipTransferredEventResponse>() {
            @Override
            public OwnershipTransferredEventResponse call(Log log) {

kswang

042530a350d04e6bd37080fce4fd1a87ba70793f8ec6d29804fbcbea5a07a9480a9c14c52570055fb939aff09d7636424cbfca4bbe94742188fee832c167fc7e53

kswang

Keybase proof

I hereby claim:

• I am kswang on github.
• I am kswang (https://keybase.io/kswang) on keybase.
• I have a public key whose fingerprint is 0A38 0D6D 151F 9E78 1B6D 32D7 43A1 EE46 2170 6F31

To claim this, I am signing this object: