Java duration (#694)

[jiminhsieh]

Thanks for your pull request. Please review the following guidelines.

• Title includes issue id.
• Description of the change added.
• Commits are squashed.
• Tests added.
• Documentation added/updated.
• Also please review CONTRIBUTING.md.

It's still WIP, but I want to discuss some of the changes.

[jiminhsieh]

After I chaged the blow part:
https://github.com/paypal/squbs/pull/706/files#diff-5a24577de789cacc6fa9751834aa36c3R97
https://github.com/paypal/squbs/pull/706/files#diff-6f9c73a3eba62c02bf35c3d0479a1f1fR23
I have to add type for the timeout, otherwise it will cause error:

[error] ~/repository/github/squbs/squbs-pattern/src/test/scala/org/squbs/pattern/timeoutpolicy/TimeoutPolicySpec.scala:46:14: ambiguous reference to overloaded definition,
[error] both method execute in class TimeoutPolicy of type [T](f: org.squbs.pattern.timeoutpolicy.TimedFn[T])T
[error] and  method execute in class TimeoutPolicy of type [T](f: scala.concurrent.duration.FiniteDuration => T)T
[error] match argument types (Comparable[_ >: java.time.Duration with scala.concurrent.duration.Duration <: Comparable[_ >: java.time.Duration with scala.concurrent.duration.Duration <: java.io.Serializable] with java.io.Serializable] with java.io.Serializable => Unit)
[error]       policy.execute(timeout => {
[error]              ^
[error] one error found

[akara]

Thanks very much for doing this. My general point is we should use the conversion utility unless we find a good reason not to.

[akara]

The time display in milliseconds is a little disturbing to me. Let me think it over and see what I can do. Otherwise I'm all good with this PR.

[akara]

I actually do not like such JMX displays at all. I understand the limitations of java.time.Duration, however, I think we can do much better. Instead of diluting the check to milliseconds, would it be better to change CircuitBreakerStateMXBeanImpl? For instance, we can change override def getMaxResetTimeout: String = maxResetTimeout.toString to override def getMaxResetTimeout: String = maxResetTimeout.toCoarsest.toString. That would be much more consumable in JMX.
Given, toCoarsest goes through a few recursions. So it is not totally free or super low cost. Placing this conversion at strategic points is important. Should we do this in the JMX bean? Should we do it at construction of the state object? Which one has the least runtime cost? JMX bean is generally not too bad. But since these are timeouts, the creation of objects that are only done at creation/materialization time is also not a bad choice. @anilgursel, what are your thoughts?

[anilgursel]

I agree @akara. Creation/materialization time makes sense.

[akara]

Just resolved merge conflicts from @jiminhsieh

[akara]

Looks like there is a good amount of merge conflict with the previously approved PR on Scala 2.11 support. Pulling code down and fixing those conflicts.

[akara]

LGTM.