Extract AbstractHealthIndicator

to make it more simple to implement HealthIndicator

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/AbstractHealthIndicator.java

+/*
+ * Copyright 2012-2014 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.boot.actuate.health;
+
+/**
+ * Base {@link HealthIndicator} implementations that encapsulates creation of
+ * {@link Health} instance and error handling.
+ * 
+ * <p>
+ * This implementation is only suitable if an {@link Exception} raised from
+ * {@link #doHealthCheck(Health)} should create a {@link Status#DOWN} health status.
+ * 
+ * @author Christian Dupuis
+ * @since 1.1.0
+ */
+public abstract class AbstractHealthIndicator implements HealthIndicator {
+
+	@Override
+	public final Health health() {
+		Health health = new Health();
+		try {
+			doHealthCheck(health);
+		}
+		catch (Exception ex) {
+			health.down().withException(ex);
+		}
+		return health;
+	}
+
+	/**
+	 * Actual health check logic.
+	 * @param health {@link Health} instance of report status.
+	 * @throws Exception any {@link Exception} that should create a {@link Status#DOWN}
+	 * system status.
+	 */
+	protected abstract void doHealthCheck(Health health) throws Exception;
+}

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/MongoHealthIndicator.java

@@ -28,7 +28,7 @@ import com.mongodb.CommandResult;
  * @author Christian Dupuis
  * @since 1.1.0
  */
-public class MongoHealthIndicator implements HealthIndicator {
+public class MongoHealthIndicator extends AbstractHealthIndicator {
 
 	private final MongoTemplate mongoTemplate;
 
@@ -38,17 +38,9 @@ public class MongoHealthIndicator implements HealthIndicator {
 	}
 
 	@Override
-	public Health health() {
-		Health health = new Health();
-		try {
-			CommandResult result = this.mongoTemplate
-					.executeCommand("{ serverStatus: 1 }");
-			health.up().withDetail("version", result.getString("version"));
-		}
-		catch (Exception ex) {
-			health.down().withException(ex);
-		}
-		return health;
+	protected void doHealthCheck(Health health) throws Exception {
+		CommandResult result = this.mongoTemplate.executeCommand("{ serverStatus: 1 }");
+		health.up().withDetail("version", result.getString("version"));
 	}
 
 }

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/RabbitHealthIndicator.java

@@ -31,7 +31,7 @@ import com.rabbitmq.client.Channel;
  * @author Christian Dupuis
  * @since 1.1.0
  */
-public class RabbitHealthIndicator implements HealthIndicator {
+public class RabbitHealthIndicator extends AbstractHealthIndicator {
 
 	private final RabbitTemplate rabbitTemplate;
 
@@ -41,23 +41,17 @@ public class RabbitHealthIndicator implements HealthIndicator {
 	}
 
 	@Override
-	public Health health() {
-		Health health = new Health();
-		try {
-			health.up().withDetail("version",
-					this.rabbitTemplate.execute(new ChannelCallback<String>() {
-
-						@Override
-						public String doInRabbit(Channel channel) throws Exception {
-							Map<String, Object> serverProperties = channel
-									.getConnection().getServerProperties();
-							return serverProperties.get("version").toString();
-						}
-					}));
-		}
-		catch (Exception ex) {
-			health.down().withException(ex);
-		}
-		return health;
+	protected void doHealthCheck(Health health) throws Exception {
+		health.up().withDetail("version",
+				this.rabbitTemplate.execute(new ChannelCallback<String>() {
+
+					@Override
+					public String doInRabbit(Channel channel) throws Exception {
+						Map<String, Object> serverProperties = channel.getConnection()
+								.getServerProperties();
+						return serverProperties.get("version").toString();
+					}
+				}));
 	}
+
 }

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/RedisHealthIndicator.java

@@ -30,7 +30,7 @@ import org.springframework.util.Assert;
  * @author Christian Dupuis
  * @since 1.1.0
  */
-public class RedisHealthIndicator implements HealthIndicator {
+public class RedisHealthIndicator extends AbstractHealthIndicator {
 
 	private final RedisConnectionFactory redisConnectionFactory;
 
@@ -40,22 +40,17 @@ public class RedisHealthIndicator implements HealthIndicator {
 	}
 
 	@Override
-	public Health health() {
-		Health health = new Health();
-
+	protected void doHealthCheck(Health health) throws Exception {
 		RedisConnection connection = null;
 		try {
 			connection = RedisConnectionUtils.getConnection(this.redisConnectionFactory);
 			Properties info = connection.info();
 			health.up().withDetail("version", info.getProperty("redis_version"));
 		}
-		catch (Exception ex) {
-			health.down().withException(ex);
-		}
 		finally {
 			RedisConnectionUtils.releaseConnection(connection,
 					this.redisConnectionFactory);
 		}
-		return health;
 	}
+
 }

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/VanillaHealthIndicator.java

@@ -22,11 +22,11 @@ package org.springframework.boot.actuate.health;
  * @author Dave Syer
  * @author Christian Dupuis
  */
-public class VanillaHealthIndicator implements HealthIndicator {
+public class VanillaHealthIndicator extends AbstractHealthIndicator {
 
 	@Override
-	public Health health() {
-		return new Health(Status.UP);
+	protected void doHealthCheck(Health health) throws Exception {
+		health.up();
 	}
 
 }