Event on Mining of a new block

Question

Does ethereum generate any event whenever a new block is mined on the chain which can trigger a daemon process(lets say java code)?

Answer 1

Using e.g. the web3 JS API, you could setup a filter and watch block changes:

var filter = web3.eth.filter('latest');

filter.watch(function(error, result){
  var block = web3.eth.getBlock(result, true);
  console.log('current block #' + block.number);
});

Answer 2

There is an org.ethereum.core.EthereumListener.java interface,which do provide a set of function which would be invoked on such event , for example onBlock(), onTransactionExecuted() etc. You can implement it or extend the EthereumListenerAdapter.java and override the method you want,and the method executes whenever the event occurs.

For example:

public class MineAndYoursListener extends EthereumListenerAdapter {
    @Override
    public void onBlock(Block block, List<TransactionReceipt> receipts) {
    // do what you want to do with my body
    // or daemon process
    }
}