Quote from: Come-from-Beyond on February 05, 2014, 10:30:16 AM

Quote from: Jean-Luc on February 05, 2014, 10:18:02 AM

Yes, override Transaction.Type.isDuplicate() to check for such duplicate transactions, trying to cancel the same order, similar to the way it is already done for alias assignment transactions.

Let's decide what a criterion to use for choosing a duplicate. We remove:

1. A transaction with lower fee
2. A transaction with earlier timestamp
3. A transaction that is received later

Currently transactions are sorted based on the Transaction.compareTo() method which is:

Code:

public int compareTo(Transaction o) {

   if (height < o.height) {

   return -1;

   } else if (height > o.height) {

   return 1;

   } else {

   // equivalent to: fee * 1048576L / getSize() > o.fee * 1048576L / o.getSize()
   if (fee * o.getSize() > o.fee * getSize()) {

   return -1;

   } else if (fee * o.getSize() < o.fee * getSize()) {

   return 1;

   } else {

   if (timestamp < o.timestamp) {

   return -1;

   } else if (timestamp > o.timestamp) {

   return 1;

   } else {

   if (index < o.index) {

   return -1;

   } else if (index > o.index) {

   return 1;

   } else {

   return 0;

   }

   }

   }

   }

   }

and the first transaction in that sort order wins in case of duplicates. I don't want to complicate it and have the logic different for different types of transactions, let's keep it same for all.