Create CircuitBreaker and check for allowsExecution

[failsafe-lib]

Create CircuitBreaker and check for allowsExecution

[chhsiao90]

Maybe try breaker.initialize() before use it.
And I notice that the CircuitBreakerProvider in the referenced issue that seams solved this problem too.

break.open()
break.close()

But I think there is some other better way then throw NPE here.

• give the CircuitBreaker close state whenever a new CircuitBreaker create
• throw IllegalStateException when CircuitBreaker not initialized

[chhsiao90]

Maybe try breaker.initialize() before use it.

Sorry, I hadn't noticed that this method is in package scope...
Currently, call close after open is the only way to use the CircuitBreaker in a standalone way

[danpersa]

yes, that's the workaround I used.

[jhalterman]

Thanks for filing. The appropriate workaround for now:

CircuitBreaker breaker = new CircuitBreaker();
breaker.close();

[chhsiao90]

Hi @jhalterman

Currently, call breaker.close() just after constructor cannot work,
because breaker.close() will call transitionTo that will determine that the new state is same as previous state, so it would not change the state to closed and still remain the state be null.

I had some modification on this.
Please see 2400b2e24f128ca5d9291daf11d95fe048782f7e

• Allow close() call just after construct
• Add unit test on CircuitBreaker
  Because the document said that it's recommended to used CircuitBreaker in standalone way,
  so I think only test on how CircuitBreak be config seams not enough, so I had some additional test on it
• Removed unused if (state != null) because the state will always not be null
• Throw IllegalStateException while state is not in a consist state

The commit still not ready for PR.
Though the test is pass, but I should make sure that there is no side effect was bring in.
And I will need more time to add more test on CircuitBreaker.

[jhalterman]

Hi @chhsiao90

I was actually working on this too... I think what I'd like is for CircuitBreaker to default to closed state. With the current code, we can't just close() the circuit after construction though because it still needs to be configured (ex: withSuccessThreshold) since the configuration is used by the ClosedState. This is too restrictive. Once I fix this, later today, I'll push my changes. I'd like to still pickup your test cases though since those look good, if you want to submit them afterwords.

[chhsiao90]

Got it, I will help about the unit test after you!

[danpersa]

I like the idea with having the default state to closed.

[chhsiao90]

Hi @jhalterman

I just find that how CircuitBreaker change d unit test had bean wrote at the state test, like OpenStateTest.
And it seems good enough for this situation.

[jhalterman]

CircuitBreaker now defaults to closed and can be reconfigured (via withSuccessThreshold, withFailureThreshold) at any time. Any executions that were recorded from a prior configuration will be carried over.