Basic Transaction Example

This example operates on two replicated regions. It begins a transaction, updates one entry in each region, and commits the result.

If the commit fails, it will be due to a CommitConflictException, which implies that a concurrent access caused a change to one of the items operated on within this transaction. This code fragment catches the exception, and it repeats the transaction attempt until the commit succeeds.

Cache c = new CacheFactory().create();

Region<String, Integer> cash = c.createRegionFactory<String, Integer>()
    .setDataPolicy(DataPolicy.REPLICATE)
    .create("cash");

Region<String, Integer> trades = c.createRegionFactory<String, Integer>()
    .setDataPolicy(DataPolicy.REPLICATE)
    .create("trades");

CacheTransactionManager txmgr = c.getCacheTransactionManager();
boolean commitConflict = false;
do {
    try {
        txmgr.begin();
        final String customer = "Customer1";
        final Integer purchase = Integer.valueOf(1000);
        // Decrement cash
        Integer cashBalance = cash.get(customer);
        Integer newBalance = 
            Integer.valueOf((cashBalance != null ? cashBalance : 0) 
                - purchase);
        cash.put(customer, newBalance);
        // Increment trades
        Integer tradeBalance = trades.get(customer);
        newBalance = 
            Integer.valueOf((tradeBalance != null ? tradeBalance : 0) 
                + purchase);

        trades.put(customer, newBalance);
        txmgr.commit();
        commitConflict = false;
    } 
    catch (CommitConflictException conflict) {
        commitConflict = true;
    }
} while (commitConflict);