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About AirSent
AirSent is a sample application included with
Enhydra that shows how to develop full-featured
Internet applications with access from both wired and
wireless devices.
The Scenario
AirSent, Inc., is a bicycle messenger delivery service in Fog City. Even in
the Internet age, items such as legal documents, timely gifts, medicine, and so
on still need to be hand-delivered. Further, traffic congestion and parking in
Fog City are so bad that bicycle travel is quicker than car travel, so AirSent
couriers use bikes.
AirSent, Inc wants to allow customers to enter orders and to automatically notify customers of completed deliveries. AirSent, Inc also wants its central office to dispatch
messengers quickly and reliably and to retrieve up-to-the-minute status on
any delivery.
AirSent has equipped all its couriers with Web phones,
so the company can dispatch couriers "on the fly" as orders are received.
Some couriers have WAP (WML) phones, some have i-mode (cHTML) phones, others have
JavaPhones. But all need to use the application.
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The Application
The AirSent application enables:
- customers to enter orders and check order status from any standard HTML browser
- an AirSent dispatcher to assign a courier as soon as a customer enters an order
- a courier to use a Web phone to check assigned orders and confirm completed deliveries
This courier model is a good example for a wireless application because couriers
by definition are mobile, and package delivery by nature is time-sensitive.
Additionally, the wireless transaction is short: couriers have to make only a
single entry on their web phone to indicate they have delivered a package.
No Web phone text entry is required. The customer, on the other hand, does enter
pickup and delivery information, but from an HTML browser on a PC, not a wireless
device.
The AirSent application has the following personae: HTML, WML, J2ME/MIDP, Flash,
and cHTML. The HTML persona is for customers using PDAs that include an HTML browser;
the WML persona is for couriers using WAP phones; the cHTML persona is for couriers using i-mode phones;
the Flash persona is for customers using PCs, and the J2ME/MIDP persona is for couriers using JavaPhones.
The J2ME/MIDP and Flash personae are particularly interesting because they use XML as a
data-interchange format. The AirSent application includes a special DTD that defines
the data set that is to be downloaded to the JavaPhone or Flash 5 client. The Java code on the
phone or the Flash 5 client parses the XML, then displays the information and allows
user interaction.
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The Technology
The application code is written in Java, and the layout is constructed in HTML,
WML, cHTML, Flash, XHTML, and Java (J2ME). Using Enhydra XMLC, the layout files are compiled
to Java classes, and manipulated via the W3C standard Document Object Model (
DOM). Enhydra XMLC enables a clean separation of the UI layout (HTML/WML/cHTML/XHTML/Flash/Java)
from the Java application.
The application code is divided into presentation, business, and data layers.
Using standard JDBC calls, the data layer communicates with the HSQL data,
using objects created with Enhydra DODS, the Data Object Design Studio.
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