CountBased.java

@Test
    public void countBased_example() throws Exception {
        MockResponse mockResponse = new MockResponse()
                .setResponseCode(500)
                .addHeader("Content-Type", "application/json;charset=utf-8");

        CircuitBreaker circuitBreaker = CircuitBreaker.of("books", CircuitBreakerConfig.custom()
                .slidingWindowSize(4)
                .permittedNumberOfCallsInHalfOpenState(2)
                .waitDurationInOpenState(Duration.ofMillis(100))
                .build());

        this.captureEvents(circuitBreaker.getEventPublisher());

        Supplier<String> withCircuitBreaker = CircuitBreaker.decorateSupplier(circuitBreaker, bookClient::findAll);

        this.repeat(10, withCircuitBreaker, mockResponse);
        Thread.sleep(1000);
        this.repeat(4, withCircuitBreaker, mockResponse);

        // then
        Assertions.assertThat(this.events)
                .extracting(CircuitBreakerEvent::getEventType)
                .containsExactly(
                        // try x10
                        CircuitBreakerEvent.Type.ERROR,
                        CircuitBreakerEvent.Type.ERROR,
                        CircuitBreakerEvent.Type.ERROR,
                        CircuitBreakerEvent.Type.ERROR, // ringBufferInClosedState is full
                        CircuitBreakerEvent.Type.FAILURE_RATE_EXCEEDED,
                        CircuitBreakerEvent.Type.STATE_TRANSITION, // from CLOSED to OPEN
                        CircuitBreakerEvent.Type.NOT_PERMITTED,
                        CircuitBreakerEvent.Type.NOT_PERMITTED,
                        CircuitBreakerEvent.Type.NOT_PERMITTED,
                        CircuitBreakerEvent.Type.NOT_PERMITTED,
                        CircuitBreakerEvent.Type.NOT_PERMITTED,
                        CircuitBreakerEvent.Type.NOT_PERMITTED,
                        // sleep waitDurationInOpenState
                        CircuitBreakerEvent.Type.STATE_TRANSITION, // from OPEN to HALF_OPEN
                        // try x4
                        CircuitBreakerEvent.Type.ERROR,
                        CircuitBreakerEvent.Type.ERROR, // ringBufferInHalfOpenState is full
                        CircuitBreakerEvent.Type.STATE_TRANSITION, // from HALF_OPEN to OPEN
                        CircuitBreakerEvent.Type.NOT_PERMITTED,
                        CircuitBreakerEvent.Type.NOT_PERMITTED
                );
    }