Caching of Hashcode in generated objects

[jasperpotts]

Problem

Computing the hashcode over and over is a performance problem. Specifically with the extra shifts to randomize that is done for better bucket distribution when objects are used as map keys.

Solution

Move all PBJ model objects from Java Record to final Java Classes. Implement code generation for constructors, fields, getter methods and toString() method. Then add a private hashCode field that is computed at construction time and caches the hashCode as it is constant as objects are immutable. We should also use the new computed cached hashCode in the equals() method to fail fast if the hashCodes do not match.

Alternatives

No response

[anthony-swirldslabs]

The core feature has been implemented at #426 .

With #467 I'm also optimizing equals() to check the precomputed $hashCode.

[anthony-swirldslabs]

The PR is merged, and the optimization will be released in PBJ v0.11.1 shortly.