Basic integration between statistics and circuit breaker

Really just a check that the existing metrics make sense. Next
step is to provide statistics for each circuit including
information on circuit status and timeouts.

src/main/java/org/springframework/retry/stats/StatisticsListener.java

@@ -37,7 +37,7 @@ public class StatisticsListener extends RetryListenerSupport {
 			RetryCallback<T, E> callback, Throwable throwable) {
 		String name = getName(context);
 		if (name != null) {
-			if (!isExhausted(context)) {
+			if (!isExhausted(context) || isGlobal(context)) {
 				// If exhausted and stateful then the retry callback was not called. If
 				// exhausted and stateless it was called, but the started counter was
 				// already incremented.
@@ -69,6 +69,10 @@ public class StatisticsListener extends RetryListenerSupport {
 		}
 	}
 
+	private boolean isGlobal(RetryContext context) {
+		return context.hasAttribute("state.global");
+	}
+
 	private boolean isExhausted(RetryContext context) {
 		return context.hasAttribute(RetryContext.EXHAUSTED);
 	}

src/test/java/org/springframework/retry/stats/CircuitBreakerStatisticsTests.java

@@ -0,0 +1,134 @@
+/*
+ * Copyright 2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.retry.stats;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.classify.BinaryExceptionClassifier;
+import org.springframework.retry.RecoveryCallback;
+import org.springframework.retry.RetryCallback;
+import org.springframework.retry.RetryContext;
+import org.springframework.retry.RetryListener;
+import org.springframework.retry.RetryStatistics;
+import org.springframework.retry.policy.CircuitBreakerRetryPolicy;
+import org.springframework.retry.policy.NeverRetryPolicy;
+import org.springframework.retry.support.DefaultRetryState;
+import org.springframework.retry.support.RetryTemplate;
+
+/**
+ * @author Dave Syer
+ *
+ */
+public class CircuitBreakerStatisticsTests {
+
+	private static final String RECOVERED = "RECOVERED";
+	private static final String RESULT = "RESULT";
+	private RetryTemplate retryTemplate;
+	private RecoveryCallback<Object> recovery;
+	private MockRetryCallback callback;
+	private DefaultRetryState state;
+
+	private StatisticsRepository repository = new DefaultStatisticsRepository();
+	private StatisticsListener listener = new StatisticsListener(repository);
+
+	@Before
+	public void init() {
+		this.callback = new MockRetryCallback();
+		this.recovery = new RecoveryCallback<Object>() {
+			@Override
+			public Object recover(RetryContext context) throws Exception {
+				return RECOVERED;
+			}
+		};
+		this.retryTemplate = new RetryTemplate();
+		retryTemplate.setListeners(new RetryListener[] {listener});
+		this.callback.setAttemptsBeforeSuccess(1);
+		// No rollback by default (so exceptions are not rethrown)
+		this.state = new DefaultRetryState("retry", new BinaryExceptionClassifier(false));
+	}
+
+	@Test
+	public void testCircuitOpenWhenNotRetryable() throws Throwable {
+		this.retryTemplate
+				.setRetryPolicy(new CircuitBreakerRetryPolicy(new NeverRetryPolicy()));
+		Object result = this.retryTemplate.execute(this.callback, this.recovery,
+				this.state);
+		RetryStatistics stats = repository.findOne("test");
+		// System.err.println(stats);
+		assertEquals(1, stats.getStartedCount());
+		assertEquals(RECOVERED, result);
+		result = this.retryTemplate.execute(this.callback, this.recovery, this.state);
+		assertEquals(RECOVERED, result);
+		assertEquals("There should be two recoveries", 2, stats.getRecoveryCount());
+		assertEquals("There should only be one error because the circuit is now open", 1, stats.getErrorCount());
+	}
+
+	@Test
+	public void testCircuitOpenWithNoRecovery() throws Throwable {
+		this.retryTemplate
+				.setRetryPolicy(new CircuitBreakerRetryPolicy(new NeverRetryPolicy()));
+		this.retryTemplate.setThrowLastExceptionOnExhausted(true);
+		try {
+			this.retryTemplate.execute(this.callback, this.state);
+		} catch (Exception e) {
+		}
+		try {
+			this.retryTemplate.execute(this.callback, this.state);
+		} catch (Exception e) {
+		}
+		RetryStatistics stats = repository.findOne("test");
+		assertEquals("There should be two recoveries", 2, stats.getAbortCount());
+		assertEquals("There should only be one error because the circuit is now open", 1, stats.getErrorCount());
+	}
+
+	protected static class MockRetryCallback implements RetryCallback<Object, Exception> {
+
+		private int attemptsBeforeSuccess;
+
+		private Exception exceptionToThrow = new Exception();
+
+		private RetryContext status;
+
+		@Override
+		public Object doWithRetry(RetryContext status) throws Exception {
+			status.setAttribute(RetryContext.NAME, "test");
+			this.status = status;
+			int attempts = (Integer) status.getAttribute("attempts");
+			attempts++;
+			status.setAttribute("attempts", attempts);
+			if (attempts <= this.attemptsBeforeSuccess) {
+				throw this.exceptionToThrow;
+			}
+			return RESULT;
+		}
+
+		public boolean isOpen() {
+			return status != null && status.getAttribute("open")==Boolean.TRUE;
+		}
+
+		public void setAttemptsBeforeSuccess(int attemptsBeforeSuccess) {
+			this.attemptsBeforeSuccess = attemptsBeforeSuccess;
+		}
+
+		public void setExceptionToThrow(Exception exceptionToThrow) {
+			this.exceptionToThrow = exceptionToThrow;
+		}
+	}
+
+}