Implementing deposit and withdraw
We want to be able to deposit and withdraw funds into and from an account. We implement these actions in the accountDetails.jsp:
| Click in the account table and select Table Æ Add Column to Right. Add three columns.
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| Select the third cell and set the width to 30 pixels in the Properties view.
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| Drag an Output component into cell four, with text Amount (- for withdraw):.
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| Drag an Input component into cell four/row two. Set the id to amountstring.
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| Drag a Button - Command component into cell five of row two. Set the id to process, and the label to Deposit/Withdraw.
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| In the Page Data view, create a request scope variable with the name amount (String). Then drag the amount variable onto the input field to create a binding of #{requestScope.amount}.
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| Select the Deposit/Withdraw button and go to the Quick Edit view to generate an action method named doProcessAction.
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| Complete the doProcessAction method in the page code (refer to 7672code\jsf\doProcessAction.txt, Example | 6-5).
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Example 16-5 Deposit and withdraw action logic
public String doProcessAction() {
String amountstring = (String)getRequestScope().get("amount");
System.out.println("deposit/withdraw amount: " + amountstring);
try {
BigDecimal amount = new BigDecimal(amountstring);
if (amount.scale() > 2) throw
new Exception("Only 2 digits allowed for cents");
Account account = getAccount();
BigDecimal balance = account.getBalance();
if (amount.doubleValue() == 0) {
throw new Exception("Amount is zero");
} else if (amount.doubleValue() > 0) {
balance = balance.add(amount);
} else {
if (balance.compareTo(amount.abs()) < 0)
throw new Exception("Withdraw amount too big");
balance = balance.add(amount);
}
account.setBalance(balance);
AccountManager accountManager = (AccountManager)
getManagedBean("accountManager");
accountManager.updateAccount(account);
System.out.println("deposit/withdraw balance: " + balance);
// create transaction
TransactionManager transactionManager = (TransactionManager)
getManagedBean("transactionManager");
Transaction t = new Transaction();
t.setId( (new com.ibm.ejs.util.Uuid()).toString() );
t.setAmount(amount.abs());
t.setTransTime( new Timestamp(System.currentTimeMillis()) );
if (amount.doubleValue() > 0) t.setTransType("Credit");
else t.setTransType("Debit");
t.setAccount(account);
transactionManager.createTransaction(t);
transactionList = null;
getTransactionList();
getRequestScope().put("amount","");
} catch (NumberFormatException e) {
getFacesContext().addMessage("amount",
new FacesMessage("Bad amount"));
} catch (Exception e) {
getFacesContext().addMessage("amount",
new FacesMessage("Deposit/withdraw failed: " + e.getMessage()));
}
return "";
}
Make sure that you import java.math.BigDecimal and java.sql.Timestamp.
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| This action logic performs the following steps:
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Retrieve the input amount.
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Verify that a withdraw amount does not exceed the balance.
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Change the balance and call the AccountManager to update the database.
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Build a transaction record and call the TransactionManager to insert the record into the database.
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Retrieve the transaction records again to display the new record in the list.
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