Group resolution for RedisMultiMetricRepository with prefix

The prefix needs to be added before looking for keys. In addition
I rationalized the constructor and final fields (it didn't make
any sense for the prefix to be mutable).

Fixes gh-927

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/repository/redis/RedisMetricRepository.java

@@ -75,7 +75,7 @@ public class RedisMetricRepository implements MetricRepository {
 
 	/**
 	 * The redis key to use to store the index of other keys. The redis store will hold a
-	 * zset under this key. Defaults to "keys.spring.metrics". REad operations, especially
+	 * zset under this key. Defaults to "keys.spring.metrics". Read operations, especially
 	 * {@link #findAll()} and {@link #count()}, will be much more efficient if the key is
 	 * unique to the {@link #setPrefix(String) prefix} of this repository.
 	 * @param key the key to set

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/repository/redis/RedisMultiMetricRepository.java

@@ -34,7 +34,7 @@ import org.springframework.util.Assert;
  * {@link MultiMetricRepository} implementation backed by a redis store. Metric values are
  * stored as regular values against a key composed of the group name prefixed with a
  * constant prefix (default "spring.groups."). The group names are stored as a zset under
- * <code>[prefix]</code> + "keys".
+ * "keys." + <code>[prefix]</code>.
  * 
  * @author Dave Syer
  */
@@ -42,30 +42,28 @@ public class RedisMultiMetricRepository implements MultiMetricRepository {
 
 	private static final String DEFAULT_METRICS_PREFIX = "spring.groups.";
 
-	private String prefix = DEFAULT_METRICS_PREFIX;
+	private final String prefix;
 
-	private String keys = "keys." + this.prefix;
+	private final String keys;
 
 	private final BoundZSetOperations<String, String> zSetOperations;
 
 	private final RedisOperations<String, String> redisOperations;
 
 	public RedisMultiMetricRepository(RedisConnectionFactory redisConnectionFactory) {
-		Assert.notNull(redisConnectionFactory, "RedisConnectionFactory must not be null");
-		this.redisOperations = RedisUtils.stringTemplate(redisConnectionFactory);
-		this.zSetOperations = this.redisOperations.boundZSetOps(this.keys);
+		this(redisConnectionFactory, DEFAULT_METRICS_PREFIX);
 	}
 
-	/**
-	 * The prefix for all metrics keys.
-	 * @param prefix the prefix to set for all metrics keys
-	 */
-	public void setPrefix(String prefix) {
+	public RedisMultiMetricRepository(RedisConnectionFactory redisConnectionFactory,
+			String prefix) {
+		Assert.notNull(redisConnectionFactory, "RedisConnectionFactory must not be null");
+		this.redisOperations = RedisUtils.stringTemplate(redisConnectionFactory);
 		if (!prefix.endsWith(".")) {
 			prefix = prefix + ".";
 		}
 		this.prefix = prefix;
-		this.keys = "keys." + this.prefix;
+		this.keys = "keys." + this.prefix.substring(0, prefix.length() - 1);
+		this.zSetOperations = this.redisOperations.boundZSetOps(this.keys);
 	}
 
 	@Override
@@ -105,7 +103,7 @@ public class RedisMultiMetricRepository implements MultiMetricRepository {
 		Set<String> range = this.zSetOperations.range(0, -1);
 		Collection<String> result = new ArrayList<String>();
 		for (String key : range) {
-			result.add(nameFor(key));
+			result.add(nameFor(this.prefix + key));
 		}
 		return range;
 	}

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/repository/redis/RedisMultiMetricRepositoryTests.java

@@ -17,11 +17,16 @@
 package org.springframework.boot.actuate.metrics.repository.redis;
 
 import java.util.Arrays;
+import java.util.List;
 
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
 import org.springframework.boot.actuate.metrics.Iterables;
 import org.springframework.boot.actuate.metrics.Metric;
 import org.springframework.data.redis.core.StringRedisTemplate;
@@ -33,27 +38,42 @@ import static org.junit.Assert.assertTrue;
 /**
  * @author Dave Syer
  */
+@RunWith(Parameterized.class)
 public class RedisMultiMetricRepositoryTests {
 
 	@Rule
 	public RedisServer redis = RedisServer.running();
 	private RedisMultiMetricRepository repository;
+	@Parameter(0)
+	public String prefix;
+
+	@Parameters
+	public static List<Object[]> parameters() {
+		return Arrays.<Object[]> asList(new Object[] { null }, new Object[] { "test" });
+	}
 
 	@Before
 	public void init() {
-		this.repository = new RedisMultiMetricRepository(this.redis.getResource());
+		if (this.prefix == null) {
+			this.prefix = "spring.groups";
+			this.repository = new RedisMultiMetricRepository(this.redis.getResource());
+		}
+		else {
+			this.repository = new RedisMultiMetricRepository(this.redis.getResource(),
+					this.prefix);
+		}
 	}
 
 	@After
 	public void clear() {
 		assertTrue(new StringRedisTemplate(this.redis.getResource()).opsForZSet().size(
-				"spring.groups.foo") > 0);
+				"keys." + this.prefix) > 0);
 		this.repository.reset("foo");
 		this.repository.reset("bar");
 		assertNull(new StringRedisTemplate(this.redis.getResource()).opsForValue().get(
-				"spring.groups.foo"));
+				this.prefix + ".foo"));
 		assertNull(new StringRedisTemplate(this.redis.getResource()).opsForValue().get(
-				"spring.groups.bar"));
+				this.prefix + ".bar"));
 	}
 
 	@Test