Tiers and components
Branch Transformation Toolkit architecture consists of components, tiers
or logical subsystems, subsystems, and Java(TM) packages, which can be used to define,
view, and package solution technologies. The solution development process
identifies the different parts of the architecture. For example, the requirements
phase identifies components, the analysis phase identifies tiers and logical
subsystems, and the design and coding phases identify physical subsystems
and Java packages.
Identifying these items during development ensures that the system structure
is consistent and has integrity.
- Components are the building blocks of toolkit-based solutions.
They are relatively independent and discrete parts that satisfy specific business
or technical functions. Components have public interfaces that allow their
functionality and implementation to evolve over time independent of the rest
of the solution. To a certain degree, a toolkit-based solution is a group
of reusable components, and the current deployed toolkit solutions are reference
configurations of how to combine components to solve a technology problem
for a customer channel.
- Tiers (Logical subsystems) are the analytical building blocks
of toolkit-based solutions. They represent a partitioning of the system that
is independent of the technology and physical implementation. The Branch Transformation
Toolkit tiers map to the J2EE solution architecture.
- Subsystems represent its physical partitioning for deployment
and execution (differing from tiers, which represent the logical partitions
of a toolkit solution). A subsystem is a physically independent part of the
system. As a result, it can be run on any computer within the system. A subsystem
can be seen as a subset of components inside a domain.
- Java packages (also just called "packages") are
the way that a toolkit-based solution delivers code. Packages provide a way
of grouping functionality for a set of related classes. They define the namespace
of a class, and follow a naming convention that commonly maps to domains and
subsystems. The naming convention used by the Branch Transformation Toolkit
is shown below:
com.ibm.dse.domainName.subsystemName.furtherPackages.Class
com.ibm.btt.domainName.subsystemName.furtherPackages.Class
The "tierName" and "subsystemName" portions of the naming
convention are determined by the system architect. The "furtherPackages" portion
is for grouping classes into more discrete functional groups within a subsystem,
and is determined by the subsystem designer.
The following chart shows how toolkit components and tiers map into the
J2EE solution architecture.