Design of the JDM API - Java Data Mining: Strategy, Standard, and Practice - page 181

When a task is executed asynchronously, JDM provides ways to
retrieve task execution information from the DME using an Execu-
tionHandle object, which is returned to the client application. Using
an ExecutionHandle object, applications can monitor and control
task execution by using status retrieval and terminate methods. The
same task cannot be executed more than once concurrently to avoid
naming conflicts for the resulting objects. Once a task has com-
pleted, or terminated, it can be re-executed. However, the user
needs to remove any created objects prior to re-execution to avoid
naming conflicts.

8.2 Modular Packages

In JDM, we use Java packages to group collections of related classes
or interfaces with similar data mining functionality. Careful pack-
age design ensures that an API is easy to understand, adopt,
extend, maintain, and reuse. One of the challenges in defining a
standard Java Data Mining API is that not all vendors will support
all functions, algorithms, or features. Java packages provide an
effective way to modularize the API by mining functions and algo-
rithms so that vendors can choose the packages that they want to
implement.
Figure 8-13 depicts the package diagram and the relationships
between various JDM packages. The gray boxes highlight the pack-
age categories in JDM. Core packages contain classes with the
required API functionality. The mining function level packages are
organized one package per function. Similarly, algorithm level
packages are organized as one package per algorithm. Note that
there are two types of algorithm level packages: algorithm settings
and model details. Vendors who do not explicitly define algorithms
can ignore the implementation of either or both of these packages.
According to the JDM conformance requirements, a vendor can
selectively choose which mining functions and algorithms to imple-
ment. To be compliant with JDM, the core packages and at least one
mining function must be supported by the vendor product. For
applications to discover what a particular vendor supports, JDM
provides an API to discover DME capabilities. This API is discussed
in Section 8.8.
Based on the object relationships in the various packages, Java
packages will have implicit relationships; these dependencies are