/** The logic here is specific to our protocol. We parse the string according to that protocol. */
private Float executeCommand(String commandLine) throws ATMException {
// Break out the command line into String[]
StringTokenizer tokenizer = new StringTokenizer(commandLine);
String commandAndParam[] = new String[tokenizer.countTokens()];
int index = 0;
while (tokenizer.hasMoreTokens()) {
commandAndParam[index++] = tokenizer.nextToken();
}
// store the command
String command = commandAndParam[0];
// Dispatch BALANCE request without further ado.
if (command.equalsIgnoreCase(Commands.BALANCE.toString())) {
return atmImplementation.getBalance();
}
// Must have 2nd arg for amount when processing DEPOSIT/WITHDRAW commands
if (commandAndParam.length < 2) {
throw new ATMException("Missing amount for command \"" + command + "\"");
}
// execute deposit or withdraw command
try {
float amount = Float.parseFloat(commandAndParam[1]);
if (command.equalsIgnoreCase(Commands.DEPOSIT.toString())) {
atmImplementation.deposit(amount);
} else if (command.equalsIgnoreCase(Commands.WITHDRAW.toString())) {
atmImplementation.withdraw(amount);
} else {
throw new ATMException("Unrecognized command: " + command);
}
} catch (NumberFormatException nfe) {
throw new ATMException("Unable to make float from input: " + commandAndParam[1]);
}
// BALANCE command returned result above. Other commands return null;
return null;
}
