org.rnorth.ducttape.circuitbreakers

Interface Breaker

public interface Breaker

A Circuit Breaker, per http://martinfowler.com/bliki/CircuitBreaker.html[the pattern of the same name].

Author:

richardnorth

Method Summary

Modifier and Type	Method and Description
State	getState()
static void	NoOp()
void	tryDo(Runnable tryIfAlive) Do something, unless the breaker is in a broken state, in which case do nothing.
void	tryDo(Runnable tryIfAlive, Runnable runIfBroken) Do something, unless the breaker is in a broken state, in which case perform a fallback action.
void	tryDo(Runnable tryIfAlive, Runnable runOnFirstFailure, Runnable runIfBroken) Do something, unless the breaker is in a broken state, in which case perform a fallback action.
<T> Optional<T>	tryGet(Callable<T> tryIfAlive) Get the result of something, unless the breaker is in a broken state, in which case get a fallback value.
<T> T	tryGet(Callable<T> tryIfAlive, Runnable runOnFirstFailure, Supplier<T> getIfBroken) Get the result of something, unless the breaker is in a broken state, in which case get a fallback value.
<T> T	tryGet(Callable<T> tryIfAlive, Supplier<T> getIfBroken) Get the result of something, unless the breaker is in a broken state, in which case get a fallback value.

Method Detail

tryDo

void tryDo(Runnable tryIfAlive,
           Runnable runOnFirstFailure,
           Runnable runIfBroken)

Do something, unless the breaker is in a broken state, in which case perform a fallback action.

Parameters:

tryIfAlive - A runnable, to be invoked unless the breaker is in `BROKEN` state

runOnFirstFailure - A runnable, to be invoked immediately if the first runnable fails

runIfBroken - A runnable, to be invoked if the breaker is in `BROKEN` state

tryDo

void tryDo(Runnable tryIfAlive,
           Runnable runIfBroken)

Do something, unless the breaker is in a broken state, in which case perform a fallback action.

Parameters:

tryIfAlive - A runnable, to be invoked unless the breaker is in `BROKEN` state

runIfBroken - A runnable, to be invoked if the breaker is in `BROKEN` state

tryDo

void tryDo(Runnable tryIfAlive)

Do something, unless the breaker is in a broken state, in which case do nothing.

Parameters:

tryIfAlive - A runnable, to be invoked unless the breaker is in `BROKEN` state

tryGet

<T> T tryGet(Callable<T> tryIfAlive,
             Runnable runOnFirstFailure,
             Supplier<T> getIfBroken)

Get the result of something, unless the breaker is in a broken state, in which case get a fallback value.

Type Parameters:

T - The type to be returned by the `tryIfAlive` callable and `getIfBroken` supplier

Parameters:

tryIfAlive - A callable, to be called unless the breaker is in `BROKEN` state. May throw a checked exception.

runOnFirstFailure - A runnable, to be invoked immediately if the first callable fails

getIfBroken - A supplier, to be invoked if the breaker is in `BROKEN` state. May not throw a checked exception.

Returns:

The value returned by either `tryIfAlive` or `getIfBroken`

tryGet

<T> T tryGet(Callable<T> tryIfAlive,
             Supplier<T> getIfBroken)

Get the result of something, unless the breaker is in a broken state, in which case get a fallback value.

Type Parameters:

T - The type to be returned by the `tryIfAlive` callable and `getIfBroken` supplier

Parameters:

tryIfAlive - A callable, to be called unless the breaker is in `BROKEN` state. May throw a checked exception.

getIfBroken - A supplier, to be invoked if the breaker is in `BROKEN` state. May not throw a checked exception.

Returns:

The value returned by either `tryIfAlive` or `getIfBroken`

tryGet

<T> Optional<T> tryGet(Callable<T> tryIfAlive)

Get the result of something, unless the breaker is in a broken state, in which case get a fallback value.

Type Parameters:

T - The type to be returned by the `tryIfAlive` callable and `getIfBroken` supplier

Parameters:

tryIfAlive - A callable, to be called unless the breaker is in `BROKEN` state. May throw a checked exception.

Returns:

An `Optional` wrapping either the value returned by `tryIfAlive`, or empty if the breaker is in `BROKEN` state or `tryIfAlive` failed

getState

State getState()

Returns:

The current state of the breaker

NoOp

static void NoOp()