Trading Services Cont

More on trading services (started in component services)

property name

simple or compound name

property value type

what sorts of values can be bound to this name

property value

the actual value

property value query

a request for a matching value

design issue with property value types and queries

how general do we make the types/ queries we permit?

issue with returning component matches in order

difficult to do uniformly - which is better between a cheap printer and one using better paper when we didn’t express a preference for either property?

how can we represent the requests

strings or structured values

naming service interfaces

bind, delete, lookup

trading service interfaces

describe, delete, lookup, lookup for all

implementing a trader step 1

maintain a data structure that can be efficiently queried for properties

implementing a trader step 2

decide an ordering relation between “acceptable” components

larger concerns with trading services

what are we trading between? all components in a single trading space? or separate traders per component sort?

note on complementarity

naming and trading are complimentary, access a component by names or by properties

options for unsatisfiability 1

leave it to the designer

options for unsatisfiability 2

return the best we have - might not meet all requirements but better than nothing