A Sample Application

The first application we developed using JAWAP was a simple horoscope feature: The Russell Grant Horoscope. This was a service that provided a user with their horoscope. The following requirements were applied:

 

Ø       The first time a user uses the service, a screen is presented requesting the user's star sign.

Ø       The horoscope for that star sign is then displayed.

Ø       The user's star sign is recorded in an LDAP directory for future use.

Ø       The user has the option of changing their star sign.

Ø       A help feature is provided if the user is not sure of their star sign.

Ø       When the user returns to the service, the star sign recorded in the LDAP directory is referenced and the relevant horoscope displayed.

Ø       The feed is provided in XML and fetched via HTTP. The feed is updated on a daily basis.

Ø       The Ericsson R320, Nokia 7110 and Motorola Timeport P7389 are to be supported.

 

As specified, the feed was to be provided in XML. Here is a snippet of the Aries and Taurus code on the 16th February 2000.

 

<horoscope type="daily" at="20000216">

  <star sign ="Aries. Mar21-Apr20">

    <text>Your home environment is due for a shake up. Whether you're a student of Feng Shui or a master, you could do worse than to steal some decorative ideas from this old oriental way of living. The introduction of anything wooden or to do with communication is excellent.</text>

  </star sign>

  <star sign ="Taurus. Apr21-May21">

    <text>You'll be up with the movers and shakers if you open your mind to new ideas and techniques. Getting involved with anything from the World Wide Web to computers per se will lead to all kinds of interesting future opportunities. A travel choice should be made today.</text>

  </star sign>

</horoscope>

 

The JAWAP framework was used, and the following implementation classes were developed:

 

 

Ø       Horoscope: Simply the identification of the service, locatable by a URL. No load distribution is provided for the first implementation.

Ø       HoroscopeServer: This is active for the deployment of the service. On instantiation, the feed object is created and a thread of the feed class is started.

Ø       Feed: The content is fetched via HTTP at instantiation. The feed is updated daily, being refreshed at midnight.

Ø       HoroscopeData: The current set of horoscopes is stored in this class and passed to the horoscope session when a user initiates a service session.

Ø       TokenStream: This class is used to parse the HoroscopeData to select a particular star sign.

Ø       HoroscopeSession: The WAP session is held in this class.

Ø       HoroscopeLDAP: The logic to fetch the user's profile is implemented in this class. For the demonstration, a dummy class is used; otherwise a directory server would be needed.

Ø       R320Display: The implementation for the Ericsson R320.

Ø       N7110Display: The implementation for the Nokia 7110.

Ø       P7389Display: The implementation for the Motorola Timeport P7389.

 

A display class exists for each WAP browser supported. For this application, the Ericsson R320, Nokia 7110 and Motorola P7389 are supported.

 

 

The Ericsson R320, illustrated above, has the smallest screen of the three devices. But if word wrap is used, the content is compatible with all the devices.

 

 

For the Nokia 7110 there is no horizontal navigation. This does not pose a compatibility problem, as the application does not have any side-by-side links. The deck size for the Nokia is different from the R320, and so this value has to be checked.

 

The Motorola Timeport P7389 uses the Phone.com browser, which is shown above, and has some differing characteristics from the other two browsers. The most significant of these is that the deck title is not automatically placed at the top of the screen.

 

Because the display is implemented in a Java class, inheritance can be used optimally. The following class model is applicable:

 

 

The Ericsson R320 was developed first, and selected as the basis for all the other devices. The classes N7110 and P7389, for the Nokia and Motorola, were extended versions of the R320, with only small changes. This was a very neat solution, as there was substantial commonality between the devices. (The button set, for example, was common to all.) The diagram above shows a possible extension for a future Nokia release where there is commonality with the 7110.