Java Reference
In-Depth Information
of the UI, multimedia support, and so on. This mechanism allows the Java
ME subsystem to be easily adapted to different UI platforms (e.g., S60 or
UIQ) and to comply with different OEM or operator requirements.
So far, this has been a high-level overview of the general architecture
which defines the separation of logical entities into different processes,
and how the various components are built and interact within the native
environment. The following sections each focus on a specific area and
discuss it in more detail.
10.2 Application Management Software
Application Management Software (AMS) is a generic term used by the
MIDP specification to describe the software component that manages the
downloading and lifecycle of MIDlets and listens for inbound notification
requests on connections that are registered in the Push Registry.
The AMS implementation in the Java ME subsystem is called Sys-
temAMS.
3
SystemAMS provides the functionality described in the MIDP
specification but also acts as a fa¸ade layer between Symbian OS and the
Java ME subsystem as a whole. Internally, SystemAMS is decoupled into
separate SystemAMS components (see Figure 10.5), each responsible for
a specific area of functionality. Below is a non-exhaustive list of some of
the SystemAMS components:
•
Core: responsible for the management and ownership of the other
components, including the servers that are used by Symbian OS to
access the SystemAMS; it runs in the main SystemAMS thread
•
Connection: responsible for all connection functionality, including
Push connections
•
Installer: responsible for all installation functionality; it runs in its own
thread
•
Launcher: responsible for the launching of MIDlet suites
•
Lifecycle: responsible for managing the lifecycle of MIDlet suites
•
Security: responsible for providing security-related functionality
As we discussed previously, the AMS runs in its own separate process,
independently from the MIDP run-time process. There are two scenarios
in which the AMS can be launched: at Symbian OS boot time or when
the user launches or installs an application (and the AMS is not already
started). At Symbian OS boot time, the SystemAMS is started in order
3
SystemAMS sources are under
\
src
\
common
\
generic
\
j2me
\
systemams
in the
Symbian OS source repository.
