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The WDN Symbian DevZone... Application Development With Celesta’s mBusiness platform
by Richard Bloor, April 22, 2002
Two of the biggest challenges facing the mobile application developer is the
ability to adapt their applications for different devices and exchanging data
with legacy back-office systems. Celesta's mBusiness platform claims to
have addressed these issues.
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Celesta's mBusiness platform is a family of products that have been
designed to address the issues of backend connectivity and cross platform
development for a range of wireless devices including the Symbian based
Nokia 9210 and 7650, Pocket PC, Palm and Java capable phones.
The wireless client, Celesta Smart Forms, was originally developed for the
Nokia 9000 series communicators. It is a XML based application
development tool that employs a local database and forms to display and
manipulate data. It includes all the necessary functionality to handle
communications between a wireless device and the Celesta mBusiness
Gateway.
A Smart Forms application consists of three sets of information:
- the Data Structure, the files which store local data
- the Interface, the forms and controls which make up the User Interface of
the application, and
- Context data, system and application variables.
The Smart Forms data structure consists of one primary table which in turn
can have sub-tables, tables that store additional data about the Master
record on a 1:1 basis, and secondary tables, which describe data with a 1:n
relationship to the Primary table. So for example the primary table in a
sales application could be the order while order line, customer and stock
data would be in secondary tables. Within the application the data is
accessed and update with SQL like instructions.
You will notice in this screen shot that the table records have cryptic
descriptor. This is because the record descriptors are transferred in any
data communication and long meaningful names use more data, which in
turn costs more to transmit. For those who prefer to develop with long
descriptive names it is possible to achieve the best of both worlds by doing a
global edit on the applications XML definition file before deploying the
application.
The Interface definition allows the developer to define the application's forms
and their behavior. A form can be designed using the form painter or
defined directly. The forms support the usual edit fields, selection lists and
radio button style controls. The behavior of the form is defined using
predefined actions associated with events such as opening or closing a form
or selecting a menu option. The actions include all the usual logic options
(If ... Then ... Else, Case) and functions to initiate SMS and/or TCP-IP
communications.
The following screen shot of the Interface definition shows the specification
of behavior when the application is opened, being to display a form.
When the application is run it displays the following form:
The third and final element is the Context data that provides both access to
system information as well as specific constants for the application. Context
items can also be a simple static data value, the result of an SQL query, the
count from an SQL query or a calculation.
At present Smart Forms applications are developed using mBuilder within
the target device's PC emulator, although users of the Nokia 9210 also have
the ability to develop Smart Forms applications on their phone.
Development for additional devices requires that the application code, which
is defined in a XML file, is moved to the other device's emulator and
adjustments made for any changes in screen size. The ambitious developers
could ignore all these tools and simply create or modify the XML file!
Shortly there will also be a PC development tool, Celesta mBuilder
Enterprise, which is currently in Beta testing, which will allow development
to all the supported platforms to be done in one environment.
The main server component is the Celesta mBusiness Gateway that handles
communications between the wireless devices and a local store and forward
database. Communications are handled either via a Mobile Phone or GSM
card installed in the server as well as through modem(s) for dialup
connections. This arrangement can handle 1 SMS message every 5 seconds.
Where higher volumes of SMS messages are anticipated direct connection to
the telecoms providers SMS message center can be achieved with SMSC
Connector. Not only does this provide a higher throughput, 1 message per
second, but also the ability to confirm that messages have been received
giving greater resilience to the overall application. Generally for large
volumes of information a data call is used.
Future enhancements will also bring the options to communicate using
http, which will be a useful option in G2.5 or G3 networks.
One of the key concerns about wireless technology for many companies is
cost. Celesta has addressed this concern in two distinct ways. They have
there own communications protocol and data compression techniques that
minimize the airtime involved in data transmission. Secondly the system
can route messages via SMS or dialup call depending on a number of factors
including cost. The store and forward nature of Smart Forms also
minimizes data transfer because unlike a system that provides full data
replication only the changed information relevant to a particular task needs
to be communicated to the handhelds or smartphone.
Addition application components, the Celesta Integration Broker, which
provides connectivity to systems like SAP, Oracle, Navision, Varial, JD
Edvards, Lotus, Sybase and Informix amongst others, Celesta XML
Connector and Celesta Remedy AR Connector provide for integration of the
mBusiness Gateway with legacy systems. Where the legacy system is not
supported by Celesta, custom code is needed to query and populate the
mBusiness Gateways store and forward database and then retrieve data
returned from the devices in the field.
Celesta's mBusiness platform is a useful tool for developing wireless
applications. It addresses the key issues of cross platform development and
wireless communications. While not providing real time access to data the
store and forward technique, with appropriate legacy interfaces, can still
ensure the mobile worker has relevant up to date information, while
minimize telecoms network traffic. The speed and ease of development
means that applications can be up and running at short notice. Even if
your organization uses Java or C++ for wireless development Celesta's
mBusiness platform could be an effective prototyping tools to test concepts
before committing to expensive development.
In a future articles we will take a closer look at the Smart Forms' mBuilder
and examine how effective a rapid application development environment it
is.
Celesta also has a number of consumer products in their LifeStyle range.
These include several utilities for the Nokia 9110, which are available for
free, and an extended messaging product called myStyle which is currently
available for the Nokia 9210 and is planned to be available for the Nokia
7650 when it is launched.
About the "WDN Symbian Guy" Richard Bloor:
Richard Bloor has 16 years experience in the IT industry. His earlier
work was largely in design and development of commercial and
manufacturing systems but more recently has focused on
development and test management of government systems.
Richard Bloor is the Mobile Applications champion at System
Architecture consultancy Equinox of Wellington, New Zealand.
Richard can be reached at rbloor@wirelessdevnet.com.
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