public class ThresholdCircuitBreaker extends AbstractCircuitBreaker<Long>
A simple implementation of the Circuit Breaker pattern that opens if the requested increment amount is greater than a given threshold.
It contains an internal counter that starts in zero, and each call increments the counter by a given amount. If the threshold is zero, the circuit breaker will be in a permanent open state.
An example of use case could be a memory circuit breaker.
long threshold = 10L;
ThresholdCircuitBreaker breaker = new ThresholdCircuitBreaker(10L);
...
public void handleRequest(Request request) {
long memoryUsed = estimateMemoryUsage(request);
if (breaker.incrementAndCheckState(memoryUsed)) {
// actually handle this request
} else {
// do something else, e.g. send an error code
}
}
#Thread safe#
AbstractCircuitBreaker.StatePROPERTY_NAME, state| Constructor and Description |
|---|
ThresholdCircuitBreaker(long threshold)
Creates a new instance of
ThresholdCircuitBreaker and initializes the threshold. |
| Modifier and Type | Method and Description |
|---|---|
boolean |
checkState()
Checks the state of this circuit breaker and changes it if necessary.
|
void |
close()
Closes this circuit breaker.
|
long |
getThreshold()
Gets the threshold.
|
boolean |
incrementAndCheckState(Long increment)
Increments the monitored value and performs a check of the current state of this
circuit breaker.
|
addChangeListener, changeState, isClosed, isOpen, isOpen, open, removeChangeListenerpublic ThresholdCircuitBreaker(long threshold)
Creates a new instance of ThresholdCircuitBreaker and initializes the threshold.
threshold - the threshold.public long getThreshold()
public boolean checkState()
CLOSED; a value
of true typically means that the current operation can continue.checkState in interface CircuitBreaker<Long>checkState in class AbstractCircuitBreaker<Long>public void close()
Resets the internal counter back to its initial value (zero).
close in interface CircuitBreaker<Long>close in class AbstractCircuitBreaker<Long>public boolean incrementAndCheckState(Long increment)
CircuitBreaker.checkState(), but the monitored
value is incremented before the state check is performed.
If the threshold is zero, the circuit breaker will be in a permanent open state.
incrementAndCheckState in interface CircuitBreaker<Long>incrementAndCheckState in class AbstractCircuitBreaker<Long>increment - value to increment in the monitored value of the circuit breakerCopyright © 2001–2018 The Apache Software Foundation. All rights reserved.