Refactor post-importAsUnconfirmed as method to be overridden by Transaction subclasses, e.g. CHAT

src/main/java/org/qortal/transaction/ChatTransaction.java

@@ -188,6 +188,16 @@ public class ChatTransaction extends Transaction {
 		return MemoryPoW.verify2(transactionBytes, POW_BUFFER_SIZE, difficulty, nonce);
 	}
 
+	/**
+	 * Ensure there's at least a skeleton account so people
+	 * can retrieve sender's public key using address, even if all their messages
+	 * expire.
+	 */
+	@Override
+	protected void onImportAsUnconfirmed() throws DataException {
+		this.getCreator().ensureAccount();
+	}
+
 	@Override
 	public void process() throws DataException {
 		throw new DataException("CHAT transactions should never be processed");

src/main/java/org/qortal/transaction/Transaction.java

@@ -800,13 +800,7 @@ public abstract class Transaction {
 			repository.getTransactionRepository().save(transactionData);
 			repository.getTransactionRepository().unconfirmTransaction(transactionData);
 
-			/*
-			 * If CHAT transaction then ensure there's at least a skeleton account so people
-			 * can retrieve sender's public key using address, even if all their messages
-			 * expire.
-			 */
-			if (transactionData.getType() == TransactionType.CHAT)
-				this.getCreator().ensureAccount();
+			this.onImportAsUnconfirmed();
 
 			repository.saveChanges();
 
@@ -816,6 +810,17 @@ public abstract class Transaction {
 		}
 	}
 
+	/**
+	 * Callback for when a transaction is imported as unconfirmed.
+	 * <p>
+	 * Called after transaction is added to repository, but before commit.
+	 * <p>
+	 * Blockchain lock is being held during this time.
+	 */
+	protected void onImportAsUnconfirmed() throws DataException {
+		/* To be optionally overridden */
+	}
+
 	/**
 	 * Returns whether transaction can be added to the blockchain.
 	 * <p>