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The HsIndex service is an event driven service that is set to
wait for a user configurable star graph. The most frequently used
star graph for HsIndex is a bale.HaystackDocument
attached to a needle.Text. When the HsIndex service
is notified of the existence of such a sub-graph it will ad a pointer
to the subgraph in a queue. Periodically it will test to see if the
cluster is in stable state
. Once the
bale.HaystackDocument has arrived in stable state, the
HsIndex service invokes the getIndexable() method.
The result of this call is some text.
HsIndex will check to see which IR systems the Haystack is
configured to use, and will pass the text to that IR system for
indexing. Currently the only defined IR system interface in Haystack
is to the Isearch system [16], which is defined in
haystack.service.ir.HsIsearch. HsIsearch extends the class
haystack.service.ir.IRSystemService which has a large set of
utility functions for taking the text generated by HsIndex
and generating something that IR systems can index.
Copyright 1998, Eytan Adar (eytan@alum.mit.edu)