Matcher
As described earlier, a mobile user must download metadata describing
services of WISs into his PDA. This metadata of a WIS
consists of:
- interface definitions of the WIS,
- domain rules of the domains used in these interface
definitions, (let us refer to these domains as X), and
- the domain rules of the ancestor domains of X.
Figure 1
Therefore, as a result of downloading, a sub-part of the DH is
maintained in the user's PDA. The download processing is shown in
Figure 1. In this figure, the domains and interface definitions
surrounded by the dotted line are packed as a package, downloaded, and
registered into the PDA.
The matcher on the user's unit uses the downloaded sub-part of
the DH, and it resolves the semantic conflict between two data of
different WISs. To do so, the matcher must find conversion paths
between two domains of the conflicting data, choose the shortest
one as a result, and determine a sequence of conversion functions
used along the path.
Figure 2
A user interface of the matcher module is shown in Figure 2. A user
can interact with the matcher through this user interface to select
the registered packages. The matcher explores each selected package
and presents the users its structure attributes and public access
methods. The matcher resolves the conflict resolutions when the user
tries to match the data from one source to an argument of the public
method of another source. After the user finishes the source-selection
and data-passing procedure as described above, he can inform the
matcher to generate the query command by selecting the 'Gen Script'
button. The generated command will be registered for later use.
Last modified: Mon Apr 24 18:19:10 JST 2000