PreMessageReceivedEventListener (bitcoinj-core 0.17-alpha1 API)

All Known Subinterfaces:

PeerDataEventListener
```
public interface PreMessageReceivedEventListener
```
Implementors can listen to events like blocks being downloaded/transactions being broadcast/connect/disconnects, they can pre-filter messages before they are processed by a Peer or PeerGroup, and they can provide transactions to remote peers when they ask for them.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`Message`	`onPreMessageReceived(Peer peer, Message m)`	Called when a message is received by a peer, before the message is processed.

- Method Detail
  - onPreMessageReceived
```
Message onPreMessageReceived(Peer peer,
                             Message m)
```
    Called when a message is received by a peer, before the message is processed. The returned message is processed instead. Returning null will cause the message to be ignored by the Peer returning the same message object allows you to see the messages received but not change them. The result from one event listeners callback is passed as "m" to the next, forming a chain.
    
    Note that this will never be called if registered with any executor other than Threading.SAME_THREAD