Declarative Transactions

ActiveRecord supports declarative transactions, which need to use ActionRecordPlugin to realize. View Interceptor-related chapters to see how to configure interceptors. The demo usage of declarative transaction is shown as bellow:

//This case is only for demonstration, some bussion logic like account status are not considered strictly.
@Before(Tx.class)
public void trans_demo() {
// Get the transfer amount.
Integer transAmount = getParaToInt("transAmount");
// Get the id of transfer-out
Integer fromAccountId = getParaToInt("fromAccountId");
// Get the id of transfer-in
Integer toAccountId = getParaToInt("toAccountId");
// Transfer out
Db.update("update account set cash = cash - ? where id = ?",
              transAmount, fromAccountId);
// Transfer in
Db.update("update account set cash = cash + ? where id = ?",
}

In above code, only a Tx interceptor is declared to add transaction support. Besides, ActiveRecord is equipped with TxByRegex, TxByActionKeys, TxByMethods to support regex(regular expression), actionKeys, actionMethods declarative transactions respectively, demo code is shown as bellow:

public void configInterceptor(Interceptors me) {
    me.add(new TxByRegex(".*save.*"));
    me.add(new TxByActionKeys("/cash/trans", "/other"));
    me.add(new TxByMethods("save", "update"));
}

In above case,TxByRegex interceptor can intercept actions via regular expression passed in and transaction would be open when actionKey is matched by regular expression.

TxByActionKeys can intercept actions for specific actionKey and open transactions. TxByMethods can intercept actions for specific methods and open transactions.

Note: MySql database only support transactions for InnoDB engine,not support MyISAM.