Top Description Methods
org.apache.commons.lang3.concurrent

public Interface CircuitBreaker<T>

Known Direct Implementers
org.apache.commons.lang3.concurrent.AbstractCircuitBreaker
Type Parameters
<T>
the type of the value monitored by this circuit breaker
An interface describing a Circuit Breaker component.

A circuit breaker can be used to protect an application against unreliable services or unexpected load. It typically monitors a specific resource. As long as this resource works as expected, it stays in state closed, meaning that the resource can be used. If problems are encountered when using the resource, the circuit breaker can switch into state open; then access to this resource is prohibited. Depending on a concrete implementation, it is possible that the circuit breaker switches back to state closed when the resource becomes available again.

This interface defines a generic protocol of a circuit breaker component. It should be sufficiently generic to be applied to multiple different use cases.

Since
3.5

Method Summary

Modifier and TypeMethod and Description
public boolean

Returns:

true if the circuit breaker is now closed; false otherwise.
checkState()

Checks the state of this circuit breaker and changes it if necessary.

public void
close()

Closes this circuit breaker.

public boolean

Returns:

true if the circuit breaker is now closed; false otherwise
incrementAndCheckState(T
value to increment in the monitored value of the circuit breaker
increment)

Increments the monitored value and performs a check of the current state of this circuit breaker.

public boolean

Returns:

the current closed state of this circuit breaker.
isClosed()

Tests the current closed state of this circuit breaker.

public boolean

Returns:

the current open state of this circuit breaker.
isOpen()

Tests the current open state of this circuit breaker.

public void
open()

Opens this circuit breaker.

Method Detail

checkStateback to summary
public boolean checkState()

Checks the state of this circuit breaker and changes it if necessary. The return value indicates whether the circuit breaker is now in state closed; a value of true typically means that the current operation can continue.

Returns:boolean

true if the circuit breaker is now closed; false otherwise.

closeback to summary
public void close()

Closes this circuit breaker. Its state is changed to closed. If this circuit breaker is already closed, this method has no effect.

incrementAndCheckStateback to summary
public boolean incrementAndCheckState(T increment)

Increments the monitored value and performs a check of the current state of this circuit breaker. This method works like checkState(), but the monitored value is incremented before the state check is performed.

Parameters
increment:T

value to increment in the monitored value of the circuit breaker

Returns:boolean

true if the circuit breaker is now closed; false otherwise

isClosedback to summary
public boolean isClosed()

Tests the current closed state of this circuit breaker. A return value of true means that the circuit breaker is currently closed. This means that everything is okay with the monitored subsystem.

Returns:boolean

the current closed state of this circuit breaker.

isOpenback to summary
public boolean isOpen()

Tests the current open state of this circuit breaker. A return value of true means that the circuit breaker is currently open indicating a problem in the monitored subsystem.

Returns:boolean

the current open state of this circuit breaker.

openback to summary
public void open()

Opens this circuit breaker. Its state is changed to open. Depending on a concrete implementation, it may close itself again if the monitored subsystem becomes available. If this circuit breaker is already open, this method has no effect.