[rules-users] Use of Drools for a product catalog retrieval in a best effort fashon

[Alessandro Terrinoni]

Hello.

 

I'm working on a project about a product catalog, which involves the use of Drools for fetching from the database layer a set of products that support a list of characteristics in a best-effort fashon

 

In detail the database is constructed with the use of dynamic characteristics, i.e. all attributes, like dimensions or weight, are not included as fields in the table cointaining the definition of the product but they are stored in a different table; then the linkage product-characteristic is stored in a third table cointaning the product id, the characteristic id and the value associated and other necessary fields.

 

Now i would use drools for getting a limited number (let's say fixed - i.e. everytime max 10) products which has a variable number of characteristic (supplied by the user) in a best-effort style. For example if i search a router with 5 ports i could retrieve also routers with 6 or 4 ports if no router with 10 ports are in the database or there are less then 10, and so on until i get 10 (or until there are no more routers - obviusly i cant get 10 if in the db there are just 7). Now this is a really simple scenario, but you can imagine one user specifing several desired characteristics. 

 

I tought about recursive use of business rules, i mean i look first for routers with X ports, then X+1 or X-1 ports, then X-2 or X+2 ports etc. but this would lead to a monster number of business rules, since the characteristics are many. Moreover, this works fine with characteristics that takes on numeric values, but what about those which takes on Strings? I.E. encription support can be AES, DES, 3DES etc. In this case I should specify one rule for each desired request and for each step, i.e. if the user wants AES support then look for AES first, then 3DES, then DES etc. OR if he wants 3DES then 3DES first, then AES etc. (just a dumb example but i hope you get the point). 

 

I see this is quite a lot of rules handling.. maybe someone has a suggestion for another approach which would simplify the process? Or maybe someone had to solve something similar and would share some knowledge with me?

 

Thanks for the attention :)

 

Cheers

Alessandro Terrinoni

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