add asShort(), asFloat() conversion methods with tests

[hannyu]

feat: complete type conversion support

• Add conversion methods: asShort(), asFloat()...etc. for all non-container nodes.
• Include test coverage for all new methods.
• Add range check in POJONode.
• Some minor fixes.

[cowtowncoder]

Good catch!

[cowtowncoder]

Also: good catch!

[cowtowncoder]

Very good! Approved as-is.

[cowtowncoder]

Excellent, thank you @hannyu!

If you want, it'd be possible to, as follow-up:

1. Improve error handling of POJONode wrt number coercion fails wrt Range checks (right now I think will throw exception for "non-numeric" values even if it's range check fail)
2. Add "optional" variants -- shortValueOpt(), floatValueOpt(), asShortOpt(), asFloatOpt()

but this is very good addition already.

[hannyu]

@cowtowncoder Very glad to contribute!

Here’s what I think:

1. Got it. I’ll give it a shot.
2. I had already noticed the missing of shortValueOpt() and floatValueOpt(). Also, it’s strange that the JDK has OptionalInt and OptionalDouble, but no OptionalShort or OptionalFloat. So, should we just go with Optional<Short>?

[cowtowncoder]

Right, for Optional- and Atomic- there's just Int/Long/Double by JDK. So yes, Optional<Float> and Optional<Short> are needed unfortunately.

Thank you very much again for working on these!