java - API design: one generic interface VS three specialized interfaces? -

java - API design: one generic interface VS three specialized interfaces? -

i'm working on tool users can utilize own annotations describe info processing workflow (like validation, transformation etc).

besides using ready-to-use annotations, users can user own: in order need declare annotation class itself, , implement annotation processor (<--it's main point of question actualy).

the configured method info processing may one:

void foo(@provide("dataid") @validate(validator.class) string str) { dosmth(str); }

there're naturally 3 groups of annotations:

those produce initial values; those transforms values (converters); those read values , perform work (validators, different consumers).

so need create choise: either create 1 interface handling these types of annotations, can one:

interface genericannotationprocessor { object processannotation(annotation annotation, object processedvalue); }

or can add together 3 intefaces api:

interface producerannotationprocessor { object produceinitvalue(annotation annotation); } interface transformerannotationprocessor { object transformvalue(annotation annotation, object currentvalue); } interface consumerannotationprocessor { void consumevalue(annotation annotation, object currentvalue); }

the first alternative not clear in use, 3rd alternative pollutes api 3 similar interfaces.

what take (first of api user) , why?

thanks!

i create first, more general interface, define 3 different implementation classes. without knowing more how using this, first instinct define interface and/or base of operations class (depending upon how much mutual implementation code shared between different processors), , add together specialized processor implementation in derived types, of whihc share mutual interface.

in using api, expect declare variable implements genericannotationprocessor, , assign appropriate implementation type depending upon needs.

it here in portland, or, @ moment, @ 50% of required caffeine level, seems me provide maximum flexibility while maximizing cade re-use.

of course, actual reuirements might dictate otherwise . . .

hope helpful!

java oop interface api-design