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Embedded-Web Distribution of the Payara Project
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) [2017-2018] Payara Foundation and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://github.com/payara/Payara/blob/master/LICENSE.txt
* See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at glassfish/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* The Payara Foundation designates this particular file as subject to the "Classpath"
* exception as provided by the Payara Foundation in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
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package fish.payara.microprofile.faulttolerance.state;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Class that represents the state of a CircuitBreaker.
* @author Andrew Pielage
* @author Jan Bernitt (2.0)
*/
public class CircuitBreakerState {
private static final Logger logger = Logger.getLogger(CircuitBreakerState.class.getName());
public enum CircuitState {
OPEN, CLOSED, HALF_OPEN
}
private final int failureThreshold;
private final AtomicInteger halfOpenSuccessfulResultsCounter = new AtomicInteger(0);
private final Map allStateTimes = new ConcurrentHashMap<>(CircuitState.values().length);
private volatile StateTime currentStateTime;
private final boolean[] failureBuffer;
private int failureIndex = 0;
private long outcomeUpdates = 0L;
public CircuitBreakerState(int requestVolumeThreshold, double failureRatio) {
this.failureBuffer = new boolean[Math.max(0, requestVolumeThreshold)];
this.failureThreshold = (int) Math.round(requestVolumeThreshold * failureRatio);
for(CircuitState state : CircuitState.values()) {
this.allStateTimes.put(state, new StateTime(state));
}
this.currentStateTime = this.allStateTimes.get(CircuitState.CLOSED);
}
/**
* Gets the current circuit state.
* @return The current circuit state
*/
public CircuitState getCircuitState() {
return this.currentStateTime.state();
}
/**
* Sets the CircuitBreaker state to the provided enum value.
* @param circuitState The state to set the CircuitBreaker to.
*/
public void setCircuitState(CircuitState circuitState) {
this.currentStateTime.update();
if (!this.currentStateTime.is(circuitState)) {
StateTime nextStateTime = allStateTimes.get(circuitState);
nextStateTime.reset();
this.currentStateTime = nextStateTime;
}
}
/**
* Records a success or failure result to the CircuitBreaker.
* @param success True for a success, false for a failure
*/
public synchronized void recordClosedOutcome(boolean success) {
failureBuffer[failureIndex] = !success;
failureIndex = (failureIndex + 1) % failureBuffer.length;
outcomeUpdates++;
}
public synchronized boolean isClosedOutcomeSuccessOnly() {
if (failureBuffer.length == 0 || outcomeUpdates < failureBuffer.length) {
return false;
}
for (boolean failure : failureBuffer) {
if (failure)
return false;
}
return true;
}
/**
* Clears the results queue.
*/
public synchronized void resetResults() {
failureIndex = 0;
outcomeUpdates = 0L;
}
/**
* Increments the successful results counter for the half open state.
*/
public void incrementHalfOpenSuccessfulResultCounter() {
this.halfOpenSuccessfulResultsCounter.incrementAndGet();
}
/**
* Resets the successful results counter for the half open state.
*/
public void resetHalfOpenSuccessfulResultCounter() {
this.halfOpenSuccessfulResultsCounter.set(0);
}
/**
* Gets the successful results counter for the half open state.
* @return The number of consecutive successful results.
*/
public int getHalfOpenSuccessfulResultCounter() {
return this.halfOpenSuccessfulResultsCounter.get();
}
/**
* Checks to see if the CircuitBreaker is over the given failure threshold.
*/
public synchronized boolean isOverFailureThreshold() {
// Only check if the queue is full
if (outcomeUpdates < failureBuffer.length) {
logger.log(Level.FINE, "CircuitBreaker results queue isn't full yet.");
return false;
}
int failures = 0;
for (boolean failure : failureBuffer) {
if (failure) {
failures++;
if (failures >= failureThreshold) {
return true;
}
}
}
return false;
}
/**
* Updates if the current state equals the provided and returns the amount of nanos.
* @return The amount of nanos.
*/
public long updateAndGet(CircuitState circuitState) {
return this.currentStateTime.is(circuitState)
? this.currentStateTime.update()
: this.allStateTimes.get(circuitState).nanos();
}
public long nanosOpen() {
return updateAndGet(CircuitState.OPEN);
}
public long nanosHalfOpen() {
return updateAndGet(CircuitState.HALF_OPEN);
}
public long nanosClosed() {
return updateAndGet(CircuitState.CLOSED);
}
public void close() {
setCircuitState(CircuitState.CLOSED);
resetHalfOpenSuccessfulResultCounter();
resetResults();
}
public void open() {
setCircuitState(CircuitState.OPEN);
resetHalfOpenSuccessfulResultCounter();
}
public void halfOpen() {
logger.log(Level.FINE, "Setting CircuitBreaker state to half open");
setCircuitState(CircuitState.HALF_OPEN);
}
public boolean halfOpenSuccessfulClosedCircuit(int successThreshold) {
incrementHalfOpenSuccessfulResultCounter();
if (getHalfOpenSuccessfulResultCounter() == successThreshold) {
close();
return true;
}
return false;
}
}