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Strictly mandatory - JSR-172 provides high-level support which does
not mandate integration with any native service.
Customizability - Customization of web services is not part of the
integration by Symbian OS licensees onto their UI platform. (The
issue of customization by Symbian OS licensees will become clearer
in Section 11.5.3.)
Consistency - Since the native Symbian OS APIs that support the
technologies required for building a web services client application
are not grouped together as a single framework, consistency is not
broken and functionality is not fragmented between client applications
that use native services and Java applications that use the pure Java
implementation. In both native and Java web-services applications,
the behavior and data handling is always application-specific.
Performance - Assuming that mobile applications should refrain from
parsing large XML files, most of the time spent in web services
scenarios is during the transport of data from one end to another, over
the air, rather than in processing data on the device. Therefore, an
optimized Java implementation is sufficient to provide fit-for-purpose
Now it is time to mention that integration does not come without costs
and the glue between the Java ME subsystem and Symbian OS has its
own overhead in terms of dynamic and static resources. Therefore, such
native integration would add considerable effort and cost but would not
give any added value to Java applications.
Having said all that, at the core of web services, there is implicit
integration with native Symbian OS services! The JSR-172 implementation
is indeed all implemented in Java but it uses other public Java ME APIs,
which are tightly integrated with native Symbian OS. For example, JSR-
172 uses , which uses
the native HTTP framework that is used by every native HTTP client
JSR-172 is a case where no integration was necessary or required to
achieve a fit-for-purpose solution. However, this is the exception and not
the common case.
11.5.3 Tight Integration with Customization: LCDUI
LCDUI is logically composed of high-level and low-level APIs. The
javax.microedition.lcdui.Screen class takes care of all user
interaction with high-level user
interface components. The various
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