Codebase exploration help

[chayan-blip]

Hi Ben,

This is a beginner question, but my understanding of Object-Oriented Programming is that just like a car there will be a "top level object" and a "top level test suite" for example which checks when pedals and steering is applied to the car it moves in the "correct direction". Similarly I was hoping to find the "top level object and its corresponding test suite" and go to the subcomponents down from there. Is this a correct ask? Please help me in exploring the codebase. I am trying to understand the purpose of each file and any help regarding the same will be highly helpful.

Thanks
Chayan

[ben-manes]

A data structure, and especially a concurrent one, will tend to disfavor OO for performance reasons. Thus, the implementation will follow different best practices than application code.

The primary classes of interest are,

• BoundedLocalCache: A bounded map with eviction policies.
• Node: The cache entry, which has code generated subclasses (see javapoet).
• BoundedBuffer and StripedBuffer: A lossy ring buffer to sample recent entry reads to replay onto the policy
• MpscGrowableArrayQueue: A write buffer to batch entry writes to replay onto the policy
• FrequencySketch: A compact histogram to estimate an entry's frequency.
• TimerWheel: A time-based priority queue for expiration
• Pacer: A scheduler for expiration removal to that ensures a slight delay to allow for better batching behavior.

These are discussed at a high-level in the design document. The remaining classes are primary scaffolding and interfaces to the external API.

The tests contain our suite as well as importing other's for cross checking (apache, eclipse, google, jdk, lincheck). To increase coverage, our tests are parameterized to run with every valid configuration using CacheSpec to instruct the CacheProvider. The test methods are kept short by extracting the assertions checks into Truth Subjects, e.g. CacheSubject. The test coverage is very broad because the implementation complexity is too high to keep every detail in my head.