ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Handling errors
You can add additional checks to the validateEmployeeXML() method—for example, to ensure that the ssn node
contains a valid number, or that the employee has at least one phone number and e-mail address defined, and that both
values are valid. You can also modify the XML so that each employee has a unique ID and specifies the ID of their
manager.
Defining the ApplicationError class
Flash Player 9 and later, Adobe AIR 1.0 and later
The ApplicationError class serves as the base class for both the FatalError and WarningError classes. The
ApplicationError class extends the Error class, and defines its own custom methods and properties, including defining
an error ID, severity, and an XML object that contains the custom error codes and messages. This class also defines
two static constants that are used to define the severity of each error type.
The ApplicationError class’s constructor method is as follows:
public function ApplicationError()
{
messages =
;
}
Each error node in the XML object contains a unique numeric code and an error message. Error messages can be easily
looked up by their error code using E4X, as seen in the following getMessageText() method:
public function getMessageText(id:int):String
{
var message:XMLList = messages.error.(@code == id);
return message[0].text();
}
The getMessageText() method takes a single integer argument, id, and returns a string. The id argument is the error
code for the error to look up. For example, passing an id of 9001 retrieves the error saying that employees must be
assigned to only one cost center. If more than one error has the same error code, ActionScript returns the error
message only for the first result found (message[0] in the returned XMLList object).
The next method in this class, getTitle(), doesn’t take any parameters and returns a string value that contains the
error ID for this specific error. This value is used to help you easily identify the exact error that occurred during
validation of the XML packet. The following excerpt shows the getTitle() method:
public function getTitle():String
{
return "Error #" + id;
}
Last updated 6/6/2012
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