OTP filters

[t2gran]

Goal / high level use-case

The goal is to create reusable, consistent way of doing filtering on the OTP APIs and configuration - and have a general implementation which can be tailred to each specific use-case. This should work with the goal of filtering transit data very efficient for performance reasons - (the idea is to use bitmaps for this).

This issue is manly a ticket for discussion.

Her is a diagram witch illustrate the design:

[leonardehrenfried]

In order to support flex it would be nice if this supported not only TripPatterns but also Trips. I sketched out a solution for flex filtering and it wasn't very hard to support both since the main methods to use (getRoute, getMode) are already present in both entities.

[t2gran]

What is the attributes you use in Route? Maybe it is better to add explisit methods: getAgencyId() & getRouteId() instead of getRoute(). But, this is only a temporary solution, I want a generic framework for this. See the drawing above. Note! The expressions will not use an interface, instead I want the the mapping between the generic expressions and the domain classes to be handled by the factories - for example using lambdas. A key thing here is that we will cash leaf expressions as bitsets, so to do the filtering we only merge bitsets - not iterating over domain entities.

[t2gran]

One thought - if we can make a cashed BitSet for every possible leaf-node in the expression, than we can eliminate the domain/entity dependency in the factories as well. Then the only thing we swap for filtering different types is the cashe.

PS! This is not possible at the moment because of the problems we have with inconsistency with RT updates. We need indexes over all entities filtered to do this. And these need to be consistent with the RT Transit Snapshot model.

[leonardehrenfried]

How can I help with moving us into the right direction?