v. 0.4. Reimplemented using serialization. Reduced number of trips to Redis server. Updating human readable parameters as keys available in Redis on each save.

Author: Ruslan Gainutdinov

README.md

@@ -2,6 +2,8 @@
 
 Drop-in enhancement for [Dropwizard Metrics](http://metrics.dropwizard.io/) which provide metric persistence using Redis DB via [Redisson](https://github.com/redisson/redisson) library.
 
+Uses [XStream](http://x-stream.github.io/) library for serialization.
+
 ## Limitations
 
 __ALPHA QUALITY__ Use only if you intend to help improve it.
@@ -42,7 +44,7 @@ Maven repository is created using [jitpack.io](https://jitpack.io/) [![](https:/
 <dependency>
 	<groupId>com.wizecore</groupId>
 	<artifactId>persistent-metrics</artifactId>
-	<version>0.3</version>
+	<version>0.4</version>
 </dependency>
 ```
 

pom.xml

@@ -4,7 +4,7 @@
 	<groupId>com.wizecore</groupId>
 	<artifactId>persistent-metrics</artifactId>
 	<packaging>jar</packaging>
-	<version>0.3</version>
+	<version>0.4</version>
 	<name>persistent-metrics</name>
 	<url>http://github.com/wizecore/persistent-metrics</url>
 
@@ -17,10 +17,16 @@
 	</properties>
 
 	<dependencies>
+		<dependency>
+			<groupId>com.thoughtworks.xstream</groupId>
+			<artifactId>xstream</artifactId>
+			<version>1.4.9</version>
+		</dependency>
 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-jdk14</artifactId>
 			<version>1.7.24</version>
+			<scope>test</scope>
 		</dependency>
 		<dependency>
 			<groupId>org.slf4j</groupId>

src/main/java/com/wizecore/metrics/PersistenceUtil.java

@@ -7,8 +7,10 @@
 import org.redisson.Redisson;
 import org.redisson.api.RAtomicDouble;
 import org.redisson.api.RAtomicLong;
+import org.redisson.api.RBucket;
 import org.redisson.api.RedissonClient;
 import org.redisson.config.Config;
+import org.redisson.config.SingleServerConfig;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -34,10 +36,15 @@ public class PersistenceUtil {
 	private static String redisConfig = null;
 
 	/**
-	 * Optional redis address. Use REDIS_ADDR environment variable to set.
+	 * Optional redis address. Use REDIS_ADDR environment variable to set. Have no effect if REDIS_CONF is set.
 	 */
 	private static String redisAddr = null;
 
+	/**
+	 * Optional redis password. Have no effect if REDIS_CONF is set.
+	 */
+	private static String redisPassword = null;
+	
 	/**
 	 * Common prefix for all values stored. By default <code>metrics.</code>
 	 * Can be specified in environment variable METRICS_PREFIX. 
@@ -76,7 +83,12 @@ protected static void init() {
 
 				if (redisConf == null && redisAddr != null && !redisAddr.equals("")) {
 					redisConf = new Config();
-					redisConf.useSingleServer().setAddress(redisAddr);
+					SingleServerConfig ss = redisConf.useSingleServer();
+					ss.setAddress(redisAddr);
+				
+					if (redisPassword != null && !redisPassword.equals("")) {
+						ss.setPassword(redisPassword);
+					}
 				}
 
 				log.info("Initializing persistent metrics via Redis with " + (redisConf != null ? redisConf.toJSON() : "defaults"));
@@ -151,6 +163,24 @@ public static RAtomicDouble createAtomicDouble(String name) {
 		}
 		return v;
 	}
+	
+	public static String getValue(String name) {
+		init();
+		RBucket<String> b = redis.getBucket(name);
+		return b.isExists() ? b.get() : null;
+	}
+	
+	public static void setValue(String name, String value) {
+		init();
+		RBucket<String> b = redis.getBucket(name);
+		b.set(value);
+	}
+	
+
+	public static RBucket<String> getBucket(String name) {
+		init();
+		return redis.getBucket(name);
+	}
 
 	public static String getRedisConfig() {
 		return redisConfig;
@@ -175,4 +205,12 @@ public static String getMetricPrefix() {
 	public static void setMetricPrefix(String metricPrefix) {
 		PersistenceUtil.metricPrefix = metricPrefix;
 	}
+
+	public static String getRedisPassword() {
+		return redisPassword;
+	}
+
+	public static void setRedisPassword(String redisPassword) {
+		PersistenceUtil.redisPassword = redisPassword;
+	}
 }

src/main/java/com/wizecore/metrics/Persistent.java

@@ -0,0 +1,6 @@
+package com.wizecore.metrics;
+
+public interface Persistent {
+
+	void save();
+}

src/main/java/com/wizecore/metrics/PersistentCounter.java

@@ -1,15 +1,36 @@
 package com.wizecore.metrics;
 
+import org.redisson.api.RAtomicLong;
+
 import com.codahale.metrics.Counter;
+import com.thoughtworks.xstream.XStream;
 
 /**
  * An incrementing and decrementing counter metric.
  */
-public class PersistentCounter extends Counter {
-    private final LongAdderAdapter count;
+public class PersistentCounter extends Counter implements Persistent {
+    private Counter value;
+    private RAtomicLong counter;
+    private String key;
 
     public PersistentCounter(String name) {
-        this.count = PersistenceUtil.createLongAdderAdapter(name);
+    	XStream x = new XStream();
+    	key = name + ".xml";
+		String xml = PersistenceUtil.getValue(key);
+		counter = PersistenceUtil.createAtomicLong(name);
+    	if (xml != null) {
+    		value = (Counter) x.fromXML(xml);
+    	} else {
+    		value = new Counter();
+        	save();
+    	}
+    }
+    
+    public void save() {
+    	XStream x = new XStream();
+    	String xml = x.toXML(value);
+    	PersistenceUtil.setValue(key, xml);
+    	counter.set(getCount());
     }
 
     /**
@@ -25,14 +46,16 @@ public void inc() {
      * @param n the amount by which the counter will be increased
      */
     public void inc(long n) {
-        count.add(n);
+        value.inc(n);
+        save();
     }
 
     /**
      * Decrement the counter by one.
      */
     public void dec() {
         dec(1);
+        save();
     }
 
     /**
@@ -41,7 +64,8 @@ public void dec() {
      * @param n the amount by which the counter will be decreased
      */
     public void dec(long n) {
-        count.add(-n);
+        value.dec(n);
+        save();
     }
 
     /**
@@ -51,6 +75,6 @@ public void dec(long n) {
      */
     @Override
     public long getCount() {
-        return count.sum();
+        return value.getCount();
     }
 }