Polish

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

@@ -30,6 +30,9 @@ import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.util.StringUtils;
 
 /**
+ * Simple implementation of {@link HealthIndicator} that returns a status and also
+ * attempts a simple database test.
+ * 
  * @author Dave Syer
  */
 public class SimpleHealthIndicator implements HealthIndicator<Map<String, Object>> {
@@ -53,8 +56,8 @@ public class SimpleHealthIndicator implements HealthIndicator<Map<String, Object
 
 	@Override
 	public Map<String, Object> health() {
-		LinkedHashMap<String, Object> map = new LinkedHashMap<String, Object>();
-		map.put("status", "ok");
+		LinkedHashMap<String, Object> health = new LinkedHashMap<String, Object>();
+		health.put("status", "ok");
 		String product = "unknown";
 		if (this.dataSource != null) {
 			try {
@@ -65,25 +68,25 @@ public class SimpleHealthIndicator implements HealthIndicator<Map<String, Object
 						return connection.getMetaData().getDatabaseProductName();
 					}
 				});
-				map.put("database", product);
+				health.put("database", product);
 			}
 			catch (DataAccessException ex) {
-				map.put("status", "error");
-				map.put("error", ex.getClass().getName() + ": " + ex.getMessage());
+				health.put("status", "error");
+				health.put("error", ex.getClass().getName() + ": " + ex.getMessage());
 			}
 			String query = detectQuery(product);
 			if (StringUtils.hasText(query)) {
 				try {
-					map.put("hello",
+					health.put("hello",
 							this.jdbcTemplate.queryForObject(query, String.class));
 				}
 				catch (Exception ex) {
-					map.put("status", "error");
-					map.put("error", ex.getClass().getName() + ": " + ex.getMessage());
+					health.put("status", "error");
+					health.put("error", ex.getClass().getName() + ": " + ex.getMessage());
 				}
 			}
 		}
-		return map;
+		return health;
 	}
 
 	protected String detectQuery(String product) {

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/Metric.java

@@ -19,6 +19,7 @@ package org.springframework.boot.actuate.metrics;
 import java.util.Date;
 
 import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
 
 /**
  * Immutable class that can be used to hold any arbitrary system measurement value (a
@@ -33,7 +34,7 @@ public class Metric<T extends Number> {
 
 	private final T value;
 
-	private Date timestamp;
+	private final Date timestamp;
 
 	/**
 	 * Create a new {@link Metric} instance for the current time.
@@ -104,41 +105,29 @@ public class Metric<T extends Number> {
 	public int hashCode() {
 		final int prime = 31;
 		int result = 1;
-		result = prime * result + ((this.name == null) ? 0 : this.name.hashCode());
-		result = prime * result
-				+ ((this.timestamp == null) ? 0 : this.timestamp.hashCode());
-		result = prime * result + ((this.value == null) ? 0 : this.value.hashCode());
+		result = prime * result + ObjectUtils.nullSafeHashCode(this.name);
+		result = prime * result + ObjectUtils.nullSafeHashCode(this.timestamp);
+		result = prime * result + ObjectUtils.nullSafeHashCode(this.value);
 		return result;
 	}
 
 	@Override
 	public boolean equals(Object obj) {
-		if (this == obj)
+		if (this == obj) {
 			return true;
-		if (obj == null)
-			return false;
-		if (getClass() != obj.getClass())
-			return false;
-		Metric<?> other = (Metric<?>) obj;
-		if (this.name == null) {
-			if (other.name != null)
-				return false;
 		}
-		else if (!this.name.equals(other.name))
+		if (obj == null) {
 			return false;
-		if (this.timestamp == null) {
-			if (other.timestamp != null)
-				return false;
 		}
-		else if (!this.timestamp.equals(other.timestamp))
-			return false;
-		if (this.value == null) {
-			if (other.value != null)
-				return false;
+		if (obj instanceof Metric) {
+			Metric<?> other = (Metric<?>) obj;
+			boolean rtn = true;
+			rtn &= ObjectUtils.nullSafeEquals(this.name, other.name);
+			rtn &= ObjectUtils.nullSafeEquals(this.timestamp, other.timestamp);
+			rtn &= ObjectUtils.nullSafeEquals(this.value, other.value);
+			return rtn;
 		}
-		else if (!this.value.equals(other.value))
-			return false;
-		return true;
+		return super.equals(obj);
 	}
 
 }

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/export/Exporter.java

@@ -22,12 +22,15 @@ package org.springframework.boot.actuate.metrics.export;
  * across a cluster), so this is the marker interface for those operations. The trigger of
  * an export operation might be periodic or even driven, but it remains outside the scope
  * of this interface. You might for instance create an instance of an Exporter and trigger
- * it using a <code>@Scheduled</code> annotation in a Spring ApplicationContext.
+ * it using a {@code @Scheduled} annotation in a Spring ApplicationContext.
  * 
  * @author Dave Syer
  */
 public interface Exporter {
 
+	/**
+	 * Export metric data.
+	 */
 	void export();
 
 }

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/export/MetricCopyExporter.java

@@ -23,11 +23,15 @@ import org.springframework.boot.actuate.metrics.reader.MetricReader;
 import org.springframework.boot.actuate.metrics.writer.MetricWriter;
 
 /**
+ * {@link Exporter} that "exports" by copying metric data from a source
+ * {@link MetricReader} to a destination {@link MetricWriter}.
+ * 
  * @author Dave Syer
  */
 public class MetricCopyExporter extends AbstractMetricExporter {
 
 	private final MetricReader reader;
+
 	private final MetricWriter writer;
 
 	public MetricCopyExporter(MetricReader reader, MetricWriter writer) {

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/export/PrefixMetricGroupExporter.java

@@ -31,7 +31,9 @@ import org.springframework.boot.actuate.metrics.writer.MetricWriter;
 public class PrefixMetricGroupExporter extends AbstractMetricExporter {
 
 	private final PrefixMetricReader reader;
+
 	private final MetricWriter writer;
+
 	private Set<String> groups = new HashSet<String>();
 
 	public PrefixMetricGroupExporter(PrefixMetricReader reader, MetricWriter writer) {
@@ -53,13 +55,13 @@ public class PrefixMetricGroupExporter extends AbstractMetricExporter {
 	}
 
 	@Override
-	protected Iterable<Metric<?>> next(String group) {
-		return this.reader.findAll(group);
+	protected Iterable<String> groups() {
+		return this.groups;
 	}
 
 	@Override
-	protected Iterable<String> groups() {
-		return this.groups;
+	protected Iterable<Metric<?>> next(String group) {
+		return this.reader.findAll(group);
 	}
 
 	@Override

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/export/PrefixMetricGroupExporterTests.java

@@ -26,12 +26,16 @@ import org.springframework.boot.actuate.metrics.repository.InMemoryMetricReposit
 import static org.junit.Assert.assertEquals;
 
 /**
+ * Tests for {@link PrefixMetricGroupExporter}.
+ * 
  * @author Dave Syer
  */
 public class PrefixMetricGroupExporterTests {
 
-	private InMemoryMetricRepository writer = new InMemoryMetricRepository();
 	private InMemoryMetricRepository reader = new InMemoryMetricRepository();
+
+	private InMemoryMetricRepository writer = new InMemoryMetricRepository();
+
 	private PrefixMetricGroupExporter exporter = new PrefixMetricGroupExporter(
 			this.reader, this.writer);