The ANSA project developed a trader which provides the basic binding
service mentioned above.
One interesting aspect of the trader is that it is possible to express
requests to resolve locations of services together with <#451#> constraints<#451#>.
These constraints are a set of simple expressions on simple attributes
of the service.
Thus it is possible to ask such questions as:
;SPM_quot;Where is an instance of service X, not more than n hops away?;SPM_quot;
or
;SPM_quot;Where is a printer server that can handle DVI and Postscript
with a zero length queue?;SPM_quot;
Another interesting idea incorporated within the trader is the idea of
linking multiple traders together. ow you do this and what search
policy you
specify is a design decision which allows you to make some of the
trade-offs discussed in the preceding section.