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From si...@apache.org
Subject [4/4] incubator-distributedlog git commit: DL-132: Enable check style for distributedlog service module.
Date Wed, 04 Jan 2017 08:44:03 GMT
DL-132: Enable check style for distributedlog service module.

Author: Xi Liu <xiliuant@gmail.com>

Reviewers: Sijie Guo <sijie@apache.org>

Closes #89 from xiliuant/xi/checkstyle_service


Project: http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/commit/1a30b0ce
Tree: http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/tree/1a30b0ce
Diff: http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/diff/1a30b0ce

Branch: refs/heads/master
Commit: 1a30b0ceb76f33eda08b611d97c150f45f239a95
Parents: 32a52a9
Author: Xi Liu <xiliuant@gmail.com>
Authored: Wed Jan 4 00:43:56 2017 -0800
Committer: Sijie Guo <sijie@apache.org>
Committed: Wed Jan 4 00:43:56 2017 -0800

----------------------------------------------------------------------
 .../resources/distributedlog/checkstyle.xml     |   2 +-
 distributedlog-service/pom.xml                  |  33 ++
 .../distributedlog/service/ClientUtils.java     |   3 +
 .../service/DistributedLogCluster.java          |  78 ++---
 .../service/DistributedLogServer.java           |  64 ++--
 .../service/DistributedLogServerApp.java        |  38 ++-
 .../service/DistributedLogServiceImpl.java      |  48 +--
 .../service/FatalErrorHandler.java              |   7 -
 .../distributedlog/service/MonitorService.java  |  29 +-
 .../service/MonitorServiceApp.java              |  16 +-
 .../service/ServerFeatureKeys.java              |   2 +-
 .../distributedlog/service/StatsFilter.java     |   8 +-
 .../service/announcer/Announcer.java            |   2 +-
 .../service/announcer/NOPAnnouncer.java         |   3 +
 .../service/announcer/ServerSetAnnouncer.java   |  10 +-
 .../service/announcer/package-info.java         |  21 ++
 .../service/balancer/Balancer.java              |   5 +
 .../service/balancer/BalancerTool.java          |  42 ++-
 .../service/balancer/ClusterBalancer.java       |  27 +-
 .../balancer/CountBasedStreamChooser.java       |   9 +-
 .../service/balancer/LimitedStreamChooser.java  |  10 +
 .../service/balancer/SimpleBalancer.java        |  17 +-
 .../service/balancer/StreamChooser.java         |   2 +-
 .../service/balancer/StreamMover.java           |   5 +-
 .../service/balancer/StreamMoverImpl.java       |   2 +-
 .../service/balancer/package-info.java          |  21 ++
 .../config/DefaultStreamConfigProvider.java     |  29 +-
 .../service/config/ServerConfiguration.java     | 106 ++++---
 .../config/ServiceStreamConfigProvider.java     |  19 +-
 .../service/config/package-info.java            |  21 ++
 .../distributedlog/service/package-info.java    |  21 ++
 .../service/placement/EqualLoadAppraiser.java   |  26 +-
 .../placement/LeastLoadPlacementPolicy.java     | 311 ++++++++++---------
 .../service/placement/LoadAppraiser.java        |  18 +-
 .../service/placement/PlacementPolicy.java      | 194 ++++++------
 .../placement/PlacementStateManager.java        |  80 +++--
 .../service/placement/ServerLoad.java           | 227 +++++++-------
 .../service/placement/StreamLoad.java           | 141 +++++----
 .../placement/ZKPlacementStateManager.java      | 236 +++++++-------
 .../service/placement/package-info.java         |  21 ++
 .../service/stream/AbstractStreamOp.java        |  23 +-
 .../service/stream/AbstractWriteOp.java         |   9 +-
 .../service/stream/BulkWriteOp.java             |  29 +-
 .../distributedlog/service/stream/DeleteOp.java |   7 +-
 .../service/stream/HeartbeatOp.java             |  11 +-
 .../service/stream/ReleaseOp.java               |   7 +-
 .../distributedlog/service/stream/Stream.java   |   7 +-
 .../service/stream/StreamFactory.java           |   3 +
 .../service/stream/StreamFactoryImpl.java       |   3 +
 .../service/stream/StreamImpl.java              |  34 +-
 .../service/stream/StreamManager.java           |   4 +-
 .../service/stream/StreamManagerImpl.java       |   5 +-
 .../distributedlog/service/stream/StreamOp.java |   2 -
 .../service/stream/StreamOpStats.java           |   2 +-
 .../service/stream/TruncateOp.java              |  11 +-
 .../distributedlog/service/stream/WriteOp.java  |  17 +-
 .../service/stream/WriteOpWithPayload.java      |   3 +
 .../service/stream/admin/AdminOp.java           |   6 +-
 .../service/stream/admin/CreateOp.java          |   7 +-
 .../service/stream/admin/StreamAdminOp.java     |   5 +-
 .../service/stream/admin/package-info.java      |  21 ++
 .../stream/limiter/DynamicRequestLimiter.java   |  21 +-
 .../stream/limiter/RequestLimiterBuilder.java   |  24 +-
 .../stream/limiter/ServiceRequestLimiter.java   |   8 +-
 .../stream/limiter/StreamAcquireLimiter.java    |   6 +-
 .../stream/limiter/StreamRequestLimiter.java    |   5 +-
 .../service/stream/limiter/package-info.java    |  21 ++
 .../service/stream/package-info.java            |  21 ++
 .../CacheableStreamPartitionConverter.java      |   3 +
 .../DelimiterStreamPartitionConverter.java      |   2 +-
 .../service/streamset/Partition.java            |   1 +
 .../service/streamset/PartitionMap.java         |   3 +
 .../service/streamset/package-info.java         |  21 ++
 .../distributedlog/service/tools/ProxyTool.java |  30 +-
 .../service/tools/package-info.java             |  21 ++
 .../service/utils/package-info.java             |  21 ++
 .../stats/CodahaleMetricsServletProvider.java   |   4 +-
 .../HealthCheckServletContextListener.java      |   2 +-
 .../stats/MetricsServletContextListener.java    |   3 +
 .../bookkeeper/stats/ServletReporter.java       |   2 +-
 .../apache/bookkeeper/stats/package-info.java   |  21 ++
 .../client/routing/LocalRoutingService.java     |   7 +-
 .../service/DistributedLogServerTestCase.java   |  33 +-
 .../service/TestDistributedLogServerBase.java   |  62 ++--
 .../TestDistributedLogServerClientRouting.java  |   9 +-
 .../service/TestDistributedLogService.java      |  88 +++---
 .../service/TestRegionUnavailable.java          |  22 +-
 .../distributedlog/service/TestStatsFilter.java |  11 +-
 .../service/balancer/TestBalancerUtils.java     |   8 +-
 .../service/balancer/TestClusterBalancer.java   |  26 +-
 .../balancer/TestCountBasedStreamChooser.java   |  16 +-
 .../service/balancer/TestSimpleBalancer.java    |  22 +-
 .../service/balancer/TestStreamMover.java       |  12 +-
 .../service/config/TestServerConfiguration.java |   8 +-
 .../config/TestStreamConfigProvider.java        |  14 +-
 .../placement/TestLeastLoadPlacementPolicy.java | 247 ++++++++-------
 .../service/placement/TestServerLoad.java       |  50 +--
 .../service/placement/TestStreamLoad.java       |  28 +-
 .../placement/TestZKPlacementStateManager.java  | 197 ++++++------
 .../service/stream/TestStreamManager.java       |  24 +-
 .../service/stream/TestStreamOp.java            |  27 +-
 .../limiter/TestServiceRequestLimiter.java      |  32 +-
 .../TestDelimiterStreamPartitionConverter.java  |   6 +-
 .../TestIdentityStreamPartitionConverter.java   |   8 +-
 .../service/streamset/TestPartitionMap.java     |   7 +-
 105 files changed, 1974 insertions(+), 1400 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-build-tools/src/main/resources/distributedlog/checkstyle.xml
----------------------------------------------------------------------
diff --git a/distributedlog-build-tools/src/main/resources/distributedlog/checkstyle.xml b/distributedlog-build-tools/src/main/resources/distributedlog/checkstyle.xml
index e1117c8..db3549f 100644
--- a/distributedlog-build-tools/src/main/resources/distributedlog/checkstyle.xml
+++ b/distributedlog-build-tools/src/main/resources/distributedlog/checkstyle.xml
@@ -260,7 +260,7 @@ page at http://checkstyle.sourceforge.net/config.html -->
     T, K, V, W, X or else be capital-case terminated with a T,
     such as MyGenericParameterT -->
     <module name="ClassTypeParameterName">
-      <property name="format" value="^(((T|K|V|W|X)[0-9]*)|([A-Z][a-z][a-zA-Z]*T))$"/>
+      <property name="format" value="^(((T|K|V|W|X|R)[0-9]*)|([A-Z][a-z][a-zA-Z]*))$"/>
       <property name="severity" value="error"/>
     </module>
 

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/pom.xml
----------------------------------------------------------------------
diff --git a/distributedlog-service/pom.xml b/distributedlog-service/pom.xml
index 052ce15..154dedb 100644
--- a/distributedlog-service/pom.xml
+++ b/distributedlog-service/pom.xml
@@ -197,6 +197,39 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-checkstyle-plugin</artifactId>
+        <version>2.17</version>
+        <dependencies>
+          <dependency>
+            <groupId>com.puppycrawl.tools</groupId>
+            <artifactId>checkstyle</artifactId>
+            <version>6.19</version>
+          </dependency>
+          <dependency>
+            <groupId>com.twitter</groupId>
+            <artifactId>distributedlog-build-tools</artifactId>
+            <version>${project.version}</version>
+          </dependency>
+        </dependencies>
+        <configuration>
+          <configLocation>distributedlog/checkstyle.xml</configLocation>
+          <suppressionsLocation>distributedlog/suppressions.xml</suppressionsLocation>
+          <consoleOutput>true</consoleOutput>
+          <failOnViolation>true</failOnViolation>
+          <includeResources>false</includeResources>
+          <includeTestSourceDirectory>true</includeTestSourceDirectory>
+        </configuration>
+        <executions>
+          <execution>
+            <phase>test-compile</phase>
+            <goals>
+              <goal>check</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
     </plugins>
   </build>
   <profiles>

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/ClientUtils.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/ClientUtils.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/ClientUtils.java
index dd9961d..da36014 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/ClientUtils.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/ClientUtils.java
@@ -21,6 +21,9 @@ import com.twitter.distributedlog.client.DistributedLogClientImpl;
 import com.twitter.distributedlog.client.monitor.MonitorServiceClient;
 import org.apache.commons.lang3.tuple.Pair;
 
+/**
+ * DistributedLog Client Related Utils.
+ */
 public class ClientUtils {
 
     public static Pair<DistributedLogClient, MonitorServiceClient> buildClient(DistributedLogClientBuilder builder) {

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogCluster.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogCluster.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogCluster.java
index a2a0ca6..029c822 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogCluster.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogCluster.java
@@ -25,6 +25,13 @@ import com.twitter.distributedlog.metadata.DLMetadata;
 import com.twitter.distributedlog.service.placement.EqualLoadAppraiser;
 import com.twitter.distributedlog.service.streamset.IdentityStreamPartitionConverter;
 import com.twitter.finagle.builder.Server;
+import java.io.File;
+import java.net.BindException;
+import java.net.InetSocketAddress;
+import java.net.URI;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
 import org.apache.bookkeeper.conf.ServerConfiguration;
 import org.apache.bookkeeper.shims.zk.ZooKeeperServerShim;
 import org.apache.bookkeeper.stats.NullStatsProvider;
@@ -35,14 +42,6 @@ import org.apache.commons.lang3.tuple.Pair;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.io.File;
-import java.net.BindException;
-import java.net.InetSocketAddress;
-import java.net.URI;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.concurrent.TimeUnit;
-
 /**
  * DistributedLog Cluster is an emulator to run distributedlog components.
  */
@@ -59,18 +58,18 @@ public class DistributedLogCluster {
      */
     public static class Builder {
 
-        int _numBookies = 3;
-        boolean _shouldStartZK = true;
-        String _zkHost = "127.0.0.1";
-        int _zkPort = 0;
-        boolean _shouldStartProxy = true;
-        int _proxyPort = 7000;
-        boolean _thriftmux = false;
-        DistributedLogConfiguration _dlConf = new DistributedLogConfiguration()
+        int numBookies = 3;
+        boolean shouldStartZK = true;
+        String zkHost = "127.0.0.1";
+        int zkPort = 0;
+        boolean shouldStartProxy = true;
+        int proxyPort = 7000;
+        boolean thriftmux = false;
+        DistributedLogConfiguration dlConf = new DistributedLogConfiguration()
                 .setLockTimeout(10)
                 .setOutputBufferSize(0)
                 .setImmediateFlushEnabled(true);
-        ServerConfiguration _bkConf = new ServerConfiguration();
+        ServerConfiguration bkConf = new ServerConfiguration();
 
         private Builder() {}
 
@@ -80,7 +79,7 @@ public class DistributedLogCluster {
          * @return builder
          */
         public Builder numBookies(int numBookies) {
-            this._numBookies = numBookies;
+            this.numBookies = numBookies;
             return this;
         }
 
@@ -92,7 +91,7 @@ public class DistributedLogCluster {
          * @return builder
          */
         public Builder shouldStartZK(boolean startZK) {
-            this._shouldStartZK = startZK;
+            this.shouldStartZK = startZK;
             return this;
         }
 
@@ -104,7 +103,7 @@ public class DistributedLogCluster {
          * @return builder
          */
         public Builder zkServers(String zkServers) {
-            this._zkHost = zkServers;
+            this.zkHost = zkServers;
             return this;
         }
 
@@ -116,7 +115,7 @@ public class DistributedLogCluster {
          * @return builder.
          */
         public Builder zkPort(int zkPort) {
-            this._zkPort = zkPort;
+            this.zkPort = zkPort;
             return this;
         }
 
@@ -128,7 +127,7 @@ public class DistributedLogCluster {
          * @return builder
          */
         public Builder shouldStartProxy(boolean startProxy) {
-            this._shouldStartProxy = startProxy;
+            this.shouldStartProxy = startProxy;
             return this;
         }
 
@@ -140,60 +139,63 @@ public class DistributedLogCluster {
          * @return builder
          */
         public Builder proxyPort(int proxyPort) {
-            this._proxyPort = proxyPort;
+            this.proxyPort = proxyPort;
             return this;
         }
 
         /**
-         * DistributedLog Configuration
+         * Set the distributedlog configuration.
          *
          * @param dlConf
          *          distributedlog configuration
          * @return builder
          */
         public Builder dlConf(DistributedLogConfiguration dlConf) {
-            this._dlConf = dlConf;
+            this.dlConf = dlConf;
             return this;
         }
 
         /**
-         * Bookkeeper server configuration
+         * Set the Bookkeeper server configuration.
          *
          * @param bkConf
          *          bookkeeper server configuration
          * @return builder
          */
         public Builder bkConf(ServerConfiguration bkConf) {
-            this._bkConf = bkConf;
+            this.bkConf = bkConf;
             return this;
         }
 
         /**
-         * Enable thriftmux for the dl server
+         * Enable thriftmux for the dl server.
          *
          * @param enabled flag to enable thriftmux
          * @return builder
          */
         public Builder thriftmux(boolean enabled) {
-            this._thriftmux = enabled;
+            this.thriftmux = enabled;
             return this;
         }
 
         public DistributedLogCluster build() throws Exception {
             // build the cluster
             return new DistributedLogCluster(
-                    _dlConf,
-                    _bkConf,
-                    _numBookies,
-                    _shouldStartZK,
-                    _zkHost,
-                    _zkPort,
-                    _shouldStartProxy,
-                    _proxyPort,
-                    _thriftmux);
+                dlConf,
+                bkConf,
+                numBookies,
+                shouldStartZK,
+                zkHost,
+                zkPort,
+                shouldStartProxy,
+                proxyPort,
+                thriftmux);
         }
     }
 
+    /**
+     * Run a distributedlog proxy server.
+     */
     public static class DLServer {
 
         static final int MAX_RETRIES = 20;

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServer.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServer.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServer.java
index a9ba125..248bcf7 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServer.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServer.java
@@ -17,32 +17,8 @@
  */
 package com.twitter.distributedlog.service;
 
-import java.io.File;
-import java.io.IOException;
-import java.net.InetSocketAddress;
-import java.net.MalformedURLException;
-import java.net.URI;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.Executors;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.TimeUnit;
-
-import scala.Option;
-import scala.Tuple2;
-
 import com.google.common.base.Optional;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
-
-import org.apache.bookkeeper.stats.NullStatsLogger;
-import org.apache.bookkeeper.stats.StatsLogger;
-import org.apache.bookkeeper.stats.StatsProvider;
-import org.apache.bookkeeper.util.ReflectionUtils;
-import org.apache.commons.configuration.ConfigurationException;
-import org.apache.commons.lang3.tuple.Pair;
-import org.apache.thrift.protocol.TBinaryProtocol;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import com.twitter.distributedlog.DistributedLogConfiguration;
 import com.twitter.distributedlog.client.routing.RoutingService;
 import com.twitter.distributedlog.config.DynamicConfigurationFactory;
@@ -72,10 +48,33 @@ import com.twitter.finagle.thrift.ClientIdRequiredFilter;
 import com.twitter.finagle.thrift.ThriftServerFramedCodec;
 import com.twitter.finagle.transport.Transport;
 import com.twitter.util.Duration;
+import java.io.File;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.MalformedURLException;
+import java.net.URI;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import org.apache.bookkeeper.stats.NullStatsLogger;
+import org.apache.bookkeeper.stats.StatsLogger;
+import org.apache.bookkeeper.stats.StatsProvider;
+import org.apache.bookkeeper.util.ReflectionUtils;
+import org.apache.commons.configuration.ConfigurationException;
+import org.apache.commons.lang3.tuple.Pair;
+import org.apache.thrift.protocol.TBinaryProtocol;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import scala.Option;
+import scala.Tuple2;
 
+/**
+ * Running the distributedlog proxy server.
+ */
 public class DistributedLogServer {
 
-    static final Logger logger = LoggerFactory.getLogger(DistributedLogServer.class);
+    private static final Logger logger = LoggerFactory.getLogger(DistributedLogServer.class);
     private static final String DEFAULT_LOAD_APPRIASER = EqualLoadAppraiser.class.getCanonicalName();
 
     private DistributedLogServiceImpl dlService = null;
@@ -124,7 +123,8 @@ public class DistributedLogServer {
         this.loadAppraiserClassStr = loadAppraiserClass;
     }
 
-    public void runServer() throws ConfigurationException, IllegalArgumentException, IOException, ClassNotFoundException {
+    public void runServer()
+        throws ConfigurationException, IllegalArgumentException, IOException, ClassNotFoundException {
         if (!uri.isPresent()) {
             throw new IllegalArgumentException("No distributedlog uri provided.");
         }
@@ -135,7 +135,8 @@ public class DistributedLogServer {
             try {
                 dlConf.loadConf(new File(configFile).toURI().toURL());
             } catch (ConfigurationException e) {
-                throw new IllegalArgumentException("Failed to load distributedlog configuration from " + configFile + ".");
+                throw new IllegalArgumentException("Failed to load distributedlog configuration from "
+                    + configFile + ".");
             } catch (MalformedURLException e) {
                 throw new IllegalArgumentException("Failed to load distributedlog configuration from malformed "
                         + configFile + ".");
@@ -185,7 +186,8 @@ public class DistributedLogServer {
         }
         Class loadAppraiserClass = Class.forName(loadAppraiserClassStr.or(DEFAULT_LOAD_APPRIASER));
         LoadAppraiser loadAppraiser = (LoadAppraiser) ReflectionUtils.newInstance(loadAppraiserClass);
-        logger.info("Supplied load appraiser class is " + loadAppraiserClassStr.get() + " Instantiated " + loadAppraiser.getClass().getCanonicalName());
+        logger.info("Supplied load appraiser class is " + loadAppraiserClassStr.get()
+            + " Instantiated " + loadAppraiser.getClass().getCanonicalName());
 
         StreamConfigProvider streamConfProvider =
                 getStreamConfigProvider(dlConf, converter);
@@ -227,7 +229,8 @@ public class DistributedLogServer {
         }
     }
 
-    private DynamicDistributedLogConfiguration getServiceDynConf(DistributedLogConfiguration dlConf) throws ConfigurationException {
+    private DynamicDistributedLogConfiguration getServiceDynConf(DistributedLogConfiguration dlConf)
+        throws ConfigurationException {
         Optional<DynamicDistributedLogConfiguration> dynConf = Optional.absent();
         if (conf.isPresent()) {
             DynamicConfigurationFactory configFactory = new DynamicConfigurationFactory(
@@ -341,7 +344,8 @@ public class DistributedLogServer {
             logger.info("Using thriftmux.");
             Tuple2<Transport.Liveness, Stack.Param<Transport.Liveness>> livenessParam = new Transport.Liveness(
                     Duration.Top(), Duration.Top(), Option.apply((Object) Boolean.valueOf(true))).mk();
-            serverBuilder = serverBuilder.stack(ThriftMuxServer$.MODULE$.configured(livenessParam._1(), livenessParam._2()));
+            serverBuilder = serverBuilder.stack(
+                ThriftMuxServer$.MODULE$.configured(livenessParam._1(), livenessParam._2()));
         }
 
         logger.info("DistributedLogServer running with the following configuration : \n{}", dlConf.getPropsAsString());

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServerApp.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServerApp.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServerApp.java
index 1c3d8d4..55ed84f 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServerApp.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServerApp.java
@@ -17,15 +17,26 @@
  */
 package com.twitter.distributedlog.service;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.twitter.distributedlog.util.CommandLineUtils.getOptionalBooleanArg;
+import static com.twitter.distributedlog.util.CommandLineUtils.getOptionalIntegerArg;
+import static com.twitter.distributedlog.util.CommandLineUtils.getOptionalStringArg;
+
 import com.google.common.base.Function;
 import com.google.common.base.Optional;
-import com.google.common.base.Preconditions;
 import com.twitter.distributedlog.DistributedLogConfiguration;
 import com.twitter.distributedlog.client.routing.RoutingService;
 import com.twitter.distributedlog.client.routing.RoutingUtils;
 import com.twitter.distributedlog.client.serverset.DLZkServerSet;
 import com.twitter.finagle.stats.NullStatsReceiver;
 import com.twitter.finagle.stats.StatsReceiver;
+import java.io.File;
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.net.URI;
+import java.util.Arrays;
+import java.util.concurrent.TimeUnit;
+import javax.annotation.Nullable;
 import org.apache.bookkeeper.stats.NullStatsProvider;
 import org.apache.bookkeeper.stats.StatsProvider;
 import org.apache.bookkeeper.util.ReflectionUtils;
@@ -38,21 +49,14 @@ import org.apache.commons.configuration.ConfigurationException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import javax.annotation.Nullable;
-import java.io.File;
-import java.io.IOException;
-import java.net.MalformedURLException;
-import java.net.URI;
-import java.util.Arrays;
-import java.util.concurrent.TimeUnit;
-
-import static com.twitter.distributedlog.util.CommandLineUtils.*;
-
+/**
+ * The launcher of the distributedlog proxy server.
+ */
 public class DistributedLogServerApp {
 
-    static final Logger logger = LoggerFactory.getLogger(DistributedLogServerApp.class);
+    private static final Logger logger = LoggerFactory.getLogger(DistributedLogServerApp.class);
 
-    private final static String USAGE = "DistributedLogServerApp [-u <uri>] [-c <conf>]";
+    private static final String USAGE = "DistributedLogServerApp [-u <uri>] [-c <conf>]";
     private final String[] args;
     private final Options options = new Options();
 
@@ -104,7 +108,8 @@ public class DistributedLogServerApp {
         }
     }
 
-    private void runCmd(CommandLine cmdline) throws IllegalArgumentException, IOException, ConfigurationException, ClassNotFoundException {
+    private void runCmd(CommandLine cmdline)
+        throws IllegalArgumentException, IOException, ConfigurationException, ClassNotFoundException {
         final StatsReceiver statsReceiver = NullStatsReceiver.get();
         Optional<String> confOptional = getOptionalStringArg(cmdline, "c");
         DistributedLogConfiguration dlConf = new DistributedLogConfiguration();
@@ -113,7 +118,8 @@ public class DistributedLogServerApp {
             try {
                 dlConf.loadConf(new File(configFile).toURI().toURL());
             } catch (ConfigurationException e) {
-                throw new IllegalArgumentException("Failed to load distributedlog configuration from " + configFile + ".");
+                throw new IllegalArgumentException("Failed to load distributedlog configuration from "
+                    + configFile + ".");
             } catch (MalformedURLException e) {
                 throw new IllegalArgumentException("Failed to load distributedlog configuration from malformed "
                         + configFile + ".");
@@ -130,7 +136,7 @@ public class DistributedLogServerApp {
                 }).or(new NullStatsProvider());
 
         final Optional<String> uriOption = getOptionalStringArg(cmdline, "u");
-        Preconditions.checkArgument(uriOption.isPresent(), "No distributedlog uri provided.");
+        checkArgument(uriOption.isPresent(), "No distributedlog uri provided.");
         URI dlUri = URI.create(uriOption.get());
 
         DLZkServerSet serverSet = DLZkServerSet.of(dlUri, (int) TimeUnit.SECONDS.toMillis(60));

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServiceImpl.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServiceImpl.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServiceImpl.java
index 5dee7fd..db1346e 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServiceImpl.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/DistributedLogServiceImpl.java
@@ -47,7 +47,6 @@ import com.twitter.distributedlog.service.placement.PlacementPolicy;
 import com.twitter.distributedlog.service.placement.ZKPlacementStateManager;
 import com.twitter.distributedlog.service.stream.BulkWriteOp;
 import com.twitter.distributedlog.service.stream.DeleteOp;
-import com.twitter.distributedlog.service.stream.admin.CreateOp;
 import com.twitter.distributedlog.service.stream.HeartbeatOp;
 import com.twitter.distributedlog.service.stream.ReleaseOp;
 import com.twitter.distributedlog.service.stream.Stream;
@@ -59,8 +58,8 @@ import com.twitter.distributedlog.service.stream.StreamOp;
 import com.twitter.distributedlog.service.stream.StreamOpStats;
 import com.twitter.distributedlog.service.stream.TruncateOp;
 import com.twitter.distributedlog.service.stream.WriteOp;
-import com.twitter.distributedlog.service.stream.admin.StreamAdminOp;
 import com.twitter.distributedlog.service.stream.WriteOpWithPayload;
+import com.twitter.distributedlog.service.stream.admin.CreateOp;
 import com.twitter.distributedlog.service.stream.admin.StreamAdminOp;
 import com.twitter.distributedlog.service.stream.limiter.ServiceRequestLimiter;
 import com.twitter.distributedlog.service.streamset.StreamPartitionConverter;
@@ -86,7 +85,6 @@ import com.twitter.util.Future;
 import com.twitter.util.FutureEventListener;
 import com.twitter.util.ScheduledThreadPoolTimer;
 import com.twitter.util.Timer;
-
 import java.io.IOException;
 import java.net.URI;
 import java.nio.ByteBuffer;
@@ -96,7 +94,6 @@ import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
-
 import org.apache.bookkeeper.feature.Feature;
 import org.apache.bookkeeper.feature.FeatureProvider;
 import org.apache.bookkeeper.stats.Counter;
@@ -105,15 +102,17 @@ import org.apache.bookkeeper.stats.StatsLogger;
 import org.jboss.netty.util.HashedWheelTimer;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import scala.runtime.BoxedUnit;
 
+/**
+ * Implementation of distributedlog thrift service.
+ */
 public class DistributedLogServiceImpl implements DistributedLogService.ServiceIface,
                                                   FatalErrorHandler {
 
-    static final Logger logger = LoggerFactory.getLogger(DistributedLogServiceImpl.class);
+    private static final Logger logger = LoggerFactory.getLogger(DistributedLogServiceImpl.class);
 
-    private final int MOVING_AVERAGE_WINDOW_SECS = 60;
+    private static final int MOVING_AVERAGE_WINDOW_SECS = 60;
 
     private final ServerConfiguration serverConfig;
     private final DistributedLogConfiguration dlConfig;
@@ -294,8 +293,8 @@ public class DistributedLogServiceImpl implements DistributedLogService.ServiceI
 
             @Override
             public Number getSample() {
-                return ServerStatus.DOWN == serverStatus ? -1 : (featureRegionStopAcceptNewStream.isAvailable() ?
-                    3 : (ServerStatus.WRITE_AND_ACCEPT == serverStatus ? 1 : 2));
+                return ServerStatus.DOWN == serverStatus ? -1 : (featureRegionStopAcceptNewStream.isAvailable()
+                    ? 3 : (ServerStatus.WRITE_AND_ACCEPT == serverStatus ? 1 : 2));
             }
         };
         this.movingAvgRpsGauge = new Gauge<Number>() {
@@ -364,8 +363,9 @@ public class DistributedLogServiceImpl implements DistributedLogService.ServiceI
         streamsStatsLogger.registerGauge("cached", this.streamCachedGauge);
 
         // Setup complete
-        logger.info("Running distributedlog server : client id {}, allocator pool {}, perstream stat {}, dlsn version {}.",
-                new Object[] { clientId, allocatorPoolName, serverConf.isPerStreamStatEnabled(), dlsnVersion });
+        logger.info("Running distributedlog server : client id {}, allocator pool {}, perstream stat {},"
+            + " dlsn version {}.",
+            new Object[] { clientId, allocatorPoolName, serverConf.isPerStreamStatEnabled(), dlsnVersion });
     }
 
     private void countStatusCode(StatusCode code) {
@@ -440,7 +440,9 @@ public class DistributedLogServiceImpl implements DistributedLogService.ServiceI
     }
 
     @Override
-    public Future<BulkWriteResponse> writeBulkWithContext(final String stream, List<ByteBuffer> data, WriteContext ctx) {
+    public Future<BulkWriteResponse> writeBulkWithContext(final String stream,
+                                                          List<ByteBuffer> data,
+                                                          WriteContext ctx) {
         bulkWritePendingStat.inc();
         receivedRecordCounter.add(data.size());
         BulkWriteOp op = new BulkWriteOp(stream, data, statsLogger, perStreamStatsLogger, streamPartitionConverter,
@@ -480,8 +482,14 @@ public class DistributedLogServiceImpl implements DistributedLogService.ServiceI
 
     @Override
     public Future<WriteResponse> truncate(String stream, String dlsn, WriteContext ctx) {
-        TruncateOp op = new TruncateOp(stream, DLSN.deserialize(dlsn), statsLogger, perStreamStatsLogger, getChecksum(ctx),
-            featureChecksumDisabled, accessControlManager);
+        TruncateOp op = new TruncateOp(
+            stream,
+            DLSN.deserialize(dlsn),
+            statsLogger,
+            perStreamStatsLogger,
+            getChecksum(ctx),
+            featureChecksumDisabled,
+            accessControlManager);
         executeStreamOp(op);
         return op.result();
     }
@@ -730,14 +738,14 @@ public class DistributedLogServiceImpl implements DistributedLogService.ServiceI
     }
 
     /**
-     * clean up the gauge before we close to help GC
+     * clean up the gauge before we close to help GC.
      */
     private void unregisterGauge(){
-        this.statsLogger.unregisterGauge("proxy_status",this.proxyStatusGauge);
-        this.statsLogger.unregisterGauge("moving_avg_rps",this.movingAvgRpsGauge);
-        this.statsLogger.unregisterGauge("moving_avg_bps",this.movingAvgBpsGauge);
-        this.statsLogger.unregisterGauge("acquired",this.streamAcquiredGauge);
-        this.statsLogger.unregisterGauge("cached",this.streamCachedGauge);
+        this.statsLogger.unregisterGauge("proxy_status", this.proxyStatusGauge);
+        this.statsLogger.unregisterGauge("moving_avg_rps", this.movingAvgRpsGauge);
+        this.statsLogger.unregisterGauge("moving_avg_bps", this.movingAvgBpsGauge);
+        this.statsLogger.unregisterGauge("acquired", this.streamAcquiredGauge);
+        this.statsLogger.unregisterGauge("cached", this.streamCachedGauge);
     }
 
     @VisibleForTesting

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/FatalErrorHandler.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/FatalErrorHandler.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/FatalErrorHandler.java
index e0a15e6..d6922b9 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/FatalErrorHandler.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/FatalErrorHandler.java
@@ -17,13 +17,6 @@
  */
 package com.twitter.distributedlog.service;
 
-import com.google.common.base.Optional;
-import com.twitter.util.Future;
-import java.io.IOException;
-import java.util.List;
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-
 /**
  * Implement handling for an unrecoverable error.
  */

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/MonitorService.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/MonitorService.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/MonitorService.java
index 7edb778..4ff5b87 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/MonitorService.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/MonitorService.java
@@ -17,9 +17,9 @@
  */
 package com.twitter.distributedlog.service;
 
+import static com.google.common.base.Preconditions.checkArgument;
 
 import com.google.common.base.Optional;
-import com.google.common.base.Preconditions;
 import com.google.common.base.Stopwatch;
 import com.google.common.collect.Sets;
 import com.google.common.hash.HashFunction;
@@ -41,14 +41,6 @@ import com.twitter.finagle.stats.StatsReceiver;
 import com.twitter.finagle.thrift.ClientId$;
 import com.twitter.util.Duration;
 import com.twitter.util.FutureEventListener;
-
-import org.apache.bookkeeper.stats.Gauge;
-import org.apache.bookkeeper.stats.StatsProvider;
-import org.apache.commons.configuration.ConfigurationException;
-import org.apache.commons.lang.StringUtils;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import java.io.File;
 import java.io.IOException;
 import java.net.MalformedURLException;
@@ -65,10 +57,19 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
+import org.apache.bookkeeper.stats.Gauge;
+import org.apache.bookkeeper.stats.StatsProvider;
+import org.apache.commons.configuration.ConfigurationException;
+import org.apache.commons.lang.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
+/**
+ * Monitor Service.
+ */
 public class MonitorService implements NamespaceListener {
 
-    static final Logger logger = LoggerFactory.getLogger(MonitorService.class);
+    private static final Logger logger = LoggerFactory.getLogger(MonitorService.class);
 
     private DistributedLogNamespace dlNamespace = null;
     private MonitorServiceClient dlClient = null;
@@ -271,9 +272,9 @@ public class MonitorService implements NamespaceListener {
     }
 
     public void runServer() throws IllegalArgumentException, IOException {
-        Preconditions.checkArgument(uriArg.isPresent(),
+        checkArgument(uriArg.isPresent(),
                 "No distributedlog uri provided.");
-        Preconditions.checkArgument(serverSetArg.isPresent(),
+        checkArgument(serverSetArg.isPresent(),
                 "No proxy server set provided.");
         if (intervalArg.isPresent()) {
             interval = intervalArg.get();
@@ -422,7 +423,7 @@ public class MonitorService implements NamespaceListener {
     }
 
     /**
-     * Close the server
+     * Close the server.
      */
     public void close() {
         logger.info("Closing monitor service.");
@@ -459,7 +460,7 @@ public class MonitorService implements NamespaceListener {
     }
 
     /**
-     * clean up the gauge before we close to help GC
+     * clean up the gauge before we close to help GC.
      */
     private void unregisterGauge(){
         statsProvider.getStatsLogger("monitor").unregisterGauge("num_streams", numOfStreamsGauge);

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/MonitorServiceApp.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/MonitorServiceApp.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/MonitorServiceApp.java
index a51a6a9..b5b4ca8 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/MonitorServiceApp.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/MonitorServiceApp.java
@@ -17,8 +17,13 @@
  */
 package com.twitter.distributedlog.service;
 
+import static com.twitter.distributedlog.util.CommandLineUtils.getOptionalBooleanArg;
+import static com.twitter.distributedlog.util.CommandLineUtils.getOptionalIntegerArg;
+import static com.twitter.distributedlog.util.CommandLineUtils.getOptionalStringArg;
+
 import com.twitter.finagle.stats.NullStatsReceiver;
 import com.twitter.finagle.stats.StatsReceiver;
+import java.io.IOException;
 import org.apache.bookkeeper.stats.NullStatsProvider;
 import org.apache.bookkeeper.stats.StatsProvider;
 import org.apache.bookkeeper.util.ReflectionUtils;
@@ -30,15 +35,16 @@ import org.apache.commons.cli.ParseException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.io.IOException;
-
-import static com.twitter.distributedlog.util.CommandLineUtils.*;
 
+/**
+ * The launcher to run monitor service.
+ */
 public class MonitorServiceApp {
 
-    static final Logger logger = LoggerFactory.getLogger(MonitorServiceApp.class);
+    private static final Logger logger = LoggerFactory.getLogger(MonitorServiceApp.class);
+
+    static final String USAGE = "MonitorService [-u <uri>] [-c <conf>] [-s serverset]";
 
-    final static String USAGE = "MonitorService [-u <uri>] [-c <conf>] [-s serverset]";
     final String[] args;
     final Options options = new Options();
 

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/ServerFeatureKeys.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/ServerFeatureKeys.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/ServerFeatureKeys.java
index 798dcf5..d779cd0 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/ServerFeatureKeys.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/ServerFeatureKeys.java
@@ -18,7 +18,7 @@
 package com.twitter.distributedlog.service;
 
 /**
- * List of feature keys used by distributedlog server
+ * List of feature keys used by distributedlog server.
  */
 public enum ServerFeatureKeys {
 

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/StatsFilter.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/StatsFilter.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/StatsFilter.java
index 6c570f6..bd0a992 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/StatsFilter.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/StatsFilter.java
@@ -18,17 +18,13 @@
 package com.twitter.distributedlog.service;
 
 import com.google.common.base.Stopwatch;
-
 import com.twitter.finagle.Service;
 import com.twitter.finagle.SimpleFilter;
 import com.twitter.util.Future;
-import com.twitter.util.FutureEventListener;
-
-import org.apache.bookkeeper.stats.StatsLogger;
+import java.util.concurrent.TimeUnit;
 import org.apache.bookkeeper.stats.Counter;
 import org.apache.bookkeeper.stats.OpStatsLogger;
-
-import java.util.concurrent.TimeUnit;
+import org.apache.bookkeeper.stats.StatsLogger;
 
 /**
  * Track distributedlog server finagle-service stats.

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/Announcer.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/Announcer.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/Announcer.java
index 89e0665..cb37088 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/Announcer.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/Announcer.java
@@ -20,7 +20,7 @@ package com.twitter.distributedlog.service.announcer;
 import java.io.IOException;
 
 /**
- * Announce service information
+ * Announce service information.
  */
 public interface Announcer {
 

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/NOPAnnouncer.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/NOPAnnouncer.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/NOPAnnouncer.java
index c686408..471f954 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/NOPAnnouncer.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/NOPAnnouncer.java
@@ -19,6 +19,9 @@ package com.twitter.distributedlog.service.announcer;
 
 import java.io.IOException;
 
+/**
+ * A no-op implementation of {@link Announcer}.
+ */
 public class NOPAnnouncer implements Announcer {
     @Override
     public void announce() throws IOException {

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/ServerSetAnnouncer.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/ServerSetAnnouncer.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/ServerSetAnnouncer.java
index ada8710..eaf4c26 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/ServerSetAnnouncer.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/ServerSetAnnouncer.java
@@ -20,9 +20,6 @@ package com.twitter.distributedlog.service.announcer;
 import com.twitter.common.zookeeper.Group;
 import com.twitter.common.zookeeper.ServerSet;
 import com.twitter.distributedlog.client.serverset.DLZkServerSet;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import java.io.IOException;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
@@ -30,10 +27,15 @@ import java.net.URI;
 import java.net.UnknownHostException;
 import java.util.HashMap;
 import java.util.Map;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
+/**
+ * ServerSet based announcer.
+ */
 public class ServerSetAnnouncer implements Announcer {
 
-    static final Logger logger = LoggerFactory.getLogger(ServerSetAnnouncer.class);
+    private static final Logger logger = LoggerFactory.getLogger(ServerSetAnnouncer.class);
 
     final String localAddr;
     final InetSocketAddress serviceEndpoint;

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/package-info.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/package-info.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/package-info.java
new file mode 100644
index 0000000..bca36df
--- /dev/null
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/announcer/package-info.java
@@ -0,0 +1,21 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+/**
+ * Announcers to announce servers to server set.
+ */
+package com.twitter.distributedlog.service.announcer;
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/Balancer.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/Balancer.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/Balancer.java
index 9dd84d0..3ffe54b 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/Balancer.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/Balancer.java
@@ -20,6 +20,11 @@ package com.twitter.distributedlog.service.balancer;
 import com.google.common.base.Optional;
 import com.google.common.util.concurrent.RateLimiter;
 
+/**
+ * Balancer Interface.
+ *
+ * <p>A balancer is used for balance the streams across the proxy cluster.
+ */
 public interface Balancer {
 
     /**

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/BalancerTool.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/BalancerTool.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/BalancerTool.java
index 2e49d92..48430df 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/BalancerTool.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/BalancerTool.java
@@ -17,8 +17,9 @@
  */
 package com.twitter.distributedlog.service.balancer;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import com.google.common.base.Optional;
-import com.google.common.base.Preconditions;
 import com.google.common.util.concurrent.RateLimiter;
 import com.twitter.common.zookeeper.ServerSet;
 import com.twitter.distributedlog.client.monitor.MonitorServiceClient;
@@ -33,6 +34,8 @@ import com.twitter.finagle.builder.ClientBuilder;
 import com.twitter.finagle.thrift.ClientId$;
 import com.twitter.util.Await;
 import com.twitter.util.Duration;
+import java.net.InetSocketAddress;
+import java.net.URI;
 import org.apache.commons.cli.CommandLine;
 import org.apache.commons.cli.Options;
 import org.apache.commons.cli.ParseException;
@@ -40,15 +43,12 @@ import org.apache.commons.lang3.tuple.Pair;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.net.InetSocketAddress;
-import java.net.URI;
-
 /**
- * Tool to rebalance cluster
+ * Tool to rebalance cluster.
  */
 public class BalancerTool extends Tool {
 
-    static final Logger logger = LoggerFactory.getLogger(BalancerTool.class);
+    private static final Logger logger = LoggerFactory.getLogger(BalancerTool.class);
 
     static DistributedLogClientBuilder createDistributedLogClientBuilder(ServerSet serverSet) {
         return DistributedLogClientBuilder.newBuilder()
@@ -66,6 +66,9 @@ public class BalancerTool extends Tool {
                                 .failFast(false));
     }
 
+    /**
+     * Base Command to run balancer.
+     */
     protected abstract static class BalancerCommand extends OptsCommand {
 
         protected Options options = new Options();
@@ -78,7 +81,8 @@ public class BalancerTool extends Tool {
         BalancerCommand(String name, String description) {
             super(name, description);
             options.addOption("rwm", "rebalance-water-mark", true, "Rebalance water mark per proxy");
-            options.addOption("rtp", "rebalance-tolerance-percentage", true, "Rebalance tolerance percentage per proxy");
+            options.addOption("rtp", "rebalance-tolerance-percentage", true,
+                "Rebalance tolerance percentage per proxy");
             options.addOption("rc", "rebalance-concurrency", true, "Concurrency to rebalance stream distribution");
             options.addOption("r", "rate", true, "Rebalance rate");
         }
@@ -105,11 +109,11 @@ public class BalancerTool extends Tool {
             if (cmdline.hasOption("r")) {
                 this.rate = Double.parseDouble(cmdline.getOptionValue("r"));
             }
-            Preconditions.checkArgument(rebalanceWaterMark >= 0,
+            checkArgument(rebalanceWaterMark >= 0,
                     "Rebalance Water Mark should be a non-negative number");
-            Preconditions.checkArgument(rebalanceTolerancePercentage >= 0.0f,
+            checkArgument(rebalanceTolerancePercentage >= 0.0f,
                     "Rebalance Tolerance Percentage should be a non-negative number");
-            Preconditions.checkArgument(rebalanceConcurrency > 0,
+            checkArgument(rebalanceConcurrency > 0,
                     "Rebalance Concurrency should be a positive number");
             if (null == rate || rate <= 0.0f) {
                 rateLimiter = Optional.absent();
@@ -133,6 +137,9 @@ public class BalancerTool extends Tool {
         protected abstract int executeCommand(CommandLine cmdline) throws Exception;
     }
 
+    /**
+     * Command to balance streams within a cluster.
+     */
     protected static class ClusterBalancerCommand extends BalancerCommand {
 
         protected URI uri;
@@ -188,7 +195,11 @@ public class BalancerTool extends Tool {
                                   ClusterBalancer balancer)
                 throws Exception {
             if (null == source) {
-                balancer.balance(rebalanceWaterMark, rebalanceTolerancePercentage, rebalanceConcurrency, getRateLimiter());
+                balancer.balance(
+                    rebalanceWaterMark,
+                    rebalanceTolerancePercentage,
+                    rebalanceConcurrency,
+                    getRateLimiter());
             } else {
                 balanceFromSource(clientBuilder, balancer, source, getRateLimiter());
             }
@@ -217,6 +228,9 @@ public class BalancerTool extends Tool {
         }
     }
 
+    /**
+     * Command to balance streams between regions.
+     */
     protected static class RegionBalancerCommand extends BalancerCommand {
 
         protected URI region1;
@@ -288,7 +302,11 @@ public class BalancerTool extends Tool {
 
         protected int runBalancer(SimpleBalancer balancer) throws Exception {
             if (null == source) {
-                balancer.balance(rebalanceWaterMark, rebalanceTolerancePercentage, rebalanceConcurrency, getRateLimiter());
+                balancer.balance(
+                    rebalanceWaterMark,
+                    rebalanceTolerancePercentage,
+                    rebalanceConcurrency,
+                    getRateLimiter());
             } else {
                 balancer.balanceAll(source, rebalanceConcurrency, getRateLimiter());
             }

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/ClusterBalancer.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/ClusterBalancer.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/ClusterBalancer.java
index 6fef648..3a3dc1f 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/ClusterBalancer.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/ClusterBalancer.java
@@ -28,10 +28,6 @@ import com.twitter.util.Await;
 import com.twitter.util.Function;
 import com.twitter.util.Future;
 import com.twitter.util.FutureEventListener;
-import org.apache.commons.lang3.tuple.Pair;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import java.io.Serializable;
 import java.net.SocketAddress;
 import java.util.ArrayList;
@@ -42,13 +38,16 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicInteger;
+import org.apache.commons.lang3.tuple.Pair;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
- * A balancer balances ownerships with a cluster of targets
+ * A balancer balances ownerships with a cluster of targets.
  */
 public class ClusterBalancer implements Balancer {
 
-    static final Logger logger = LoggerFactory.getLogger(ClusterBalancer.class);
+    private static final Logger logger = LoggerFactory.getLogger(ClusterBalancer.class);
 
     /**
      * Represent a single host. Ordered by number of streams in desc order.
@@ -205,7 +204,8 @@ public class ClusterBalancer implements Balancer {
             }
 
             int moveFromLowWaterMark;
-            int moveToHighWaterMark = Math.max(1, (int) (averageLoad + averageLoad * rebalanceTolerancePercentage / 100.0f));
+            int moveToHighWaterMark =
+                Math.max(1, (int) (averageLoad + averageLoad * rebalanceTolerancePercentage / 100.0f));
 
             if (hostIdxMoveFrom >= 0) {
                 moveFromLowWaterMark = Math.max(0, rebalanceWaterMark);
@@ -220,7 +220,8 @@ public class ClusterBalancer implements Balancer {
                 AtomicInteger moveFrom = new AtomicInteger(0);
                 AtomicInteger moveTo = new AtomicInteger(hosts.size() - 1);
                 while (moveFrom.get() < moveTo.get()) {
-                    moveStreams(hosts, moveFrom, moveFromLowWaterMark, moveTo, moveToHighWaterMark, rebalanceRateLimiter);
+                    moveStreams(hosts, moveFrom, moveFromLowWaterMark,
+                        moveTo, moveToHighWaterMark, rebalanceRateLimiter);
                     moveFrom.incrementAndGet();
                 }
             }
@@ -244,8 +245,14 @@ public class ClusterBalancer implements Balancer {
         }
 
         if (logger.isDebugEnabled()) {
-            logger.debug("Moving streams : hosts = {}, from = {}, to = {} : from_low_water_mark = {}, to_high_water_mark = {}",
-                         new Object[] { hosts, hostIdxMoveFrom.get(), hostIdxMoveTo.get(), moveFromLowWaterMark, moveToHighWaterMark });
+            logger.debug("Moving streams : hosts = {}, from = {}, to = {} :"
+                + " from_low_water_mark = {}, to_high_water_mark = {}",
+                new Object[] {
+                    hosts,
+                    hostIdxMoveFrom.get(),
+                    hostIdxMoveTo.get(),
+                    moveFromLowWaterMark,
+                    moveToHighWaterMark });
         }
 
         Host hostMoveFrom = hosts.get(hostIdxMoveFrom.get());

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/CountBasedStreamChooser.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/CountBasedStreamChooser.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/CountBasedStreamChooser.java
index 0a267ea..fab37b3 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/CountBasedStreamChooser.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/CountBasedStreamChooser.java
@@ -17,8 +17,7 @@
  */
 package com.twitter.distributedlog.service.balancer;
 
-import com.google.common.base.Preconditions;
-import org.apache.commons.lang3.tuple.Pair;
+import static com.google.common.base.Preconditions.checkArgument;
 
 import java.io.Serializable;
 import java.net.SocketAddress;
@@ -29,7 +28,11 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import org.apache.commons.lang3.tuple.Pair;
 
+/**
+ * A stream chooser based on number of streams.
+ */
 class CountBasedStreamChooser implements StreamChooser, Serializable,
         Comparator<Pair<SocketAddress, LinkedList<String>>> {
 
@@ -46,7 +49,7 @@ class CountBasedStreamChooser implements StreamChooser, Serializable,
     int next;
 
     CountBasedStreamChooser(Map<SocketAddress, Set<String>> streams) {
-        Preconditions.checkArgument(streams.size() > 0, "Only support no-empty streams distribution");
+        checkArgument(streams.size() > 0, "Only support no-empty streams distribution");
         streamsDistribution = new ArrayList<Pair<SocketAddress, LinkedList<String>>>(streams.size());
         for (Map.Entry<SocketAddress, Set<String>> entry : streams.entrySet()) {
             LinkedList<String> randomizedStreams = new LinkedList<String>(entry.getValue());

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/LimitedStreamChooser.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/LimitedStreamChooser.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/LimitedStreamChooser.java
index d0e294d..069e596 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/LimitedStreamChooser.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/LimitedStreamChooser.java
@@ -17,8 +17,18 @@
  */
 package com.twitter.distributedlog.service.balancer;
 
+/**
+ * A stream chooser that can only choose limited number of streams.
+ */
 public class LimitedStreamChooser implements StreamChooser {
 
+  /**
+   * Create a limited stream chooser by {@code limit}.
+   *
+   * @param underlying the underlying stream chooser.
+   * @param limit the limit of number of streams to choose.
+   * @return the limited stream chooser.
+   */
     public static LimitedStreamChooser of(StreamChooser underlying, int limit) {
         return new LimitedStreamChooser(underlying, limit);
     }

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/SimpleBalancer.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/SimpleBalancer.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/SimpleBalancer.java
index 6913e4a..b205d5f 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/SimpleBalancer.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/SimpleBalancer.java
@@ -21,9 +21,6 @@ import com.google.common.base.Optional;
 import com.google.common.util.concurrent.RateLimiter;
 import com.twitter.distributedlog.client.monitor.MonitorServiceClient;
 import com.twitter.distributedlog.service.DistributedLogClient;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import java.net.SocketAddress;
 import java.util.HashMap;
 import java.util.Map;
@@ -31,13 +28,15 @@ import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * A balancer balances ownerships between two targets.
  */
 public class SimpleBalancer implements Balancer {
 
-    static final Logger logger = LoggerFactory.getLogger(SimpleBalancer.class);
+    private static final Logger logger = LoggerFactory.getLogger(SimpleBalancer.class);
 
     protected final String target1;
     protected final String target2;
@@ -120,8 +119,8 @@ public class SimpleBalancer implements Balancer {
         loadDistribution.put(target, targetStreamCount);
 
         // Calculate how many streams to be rebalanced from src region to target region
-        int numStreamsToRebalance =
-                BalancerUtils.calculateNumStreamsToRebalance(source, loadDistribution, rebalanceWaterMark, rebalanceTolerancePercentage);
+        int numStreamsToRebalance = BalancerUtils.calculateNumStreamsToRebalance(
+            source, loadDistribution, rebalanceWaterMark, rebalanceTolerancePercentage);
 
         if (numStreamsToRebalance <= 0) {
             logger.info("No streams need to be rebalanced from '{}' to '{}'.", source, target);
@@ -130,7 +129,8 @@ public class SimpleBalancer implements Balancer {
 
         StreamChooser streamChooser =
                 LimitedStreamChooser.of(new CountBasedStreamChooser(srcDistribution), numStreamsToRebalance);
-        StreamMover streamMover = new StreamMoverImpl(source, srcClient, srcMonitor, target, targetClient, targetMonitor);
+        StreamMover streamMover =
+            new StreamMoverImpl(source, srcClient, srcMonitor, target, targetClient, targetMonitor);
 
         moveStreams(streamChooser, streamMover, rebalanceConcurrency, rebalanceRateLimiter);
     }
@@ -166,7 +166,8 @@ public class SimpleBalancer implements Balancer {
         }
 
         StreamChooser streamChooser = new CountBasedStreamChooser(distribution);
-        StreamMover streamMover = new StreamMoverImpl(source, sourceClient, sourceMonitor, target, targetClient, targetMonitor);
+        StreamMover streamMover =
+            new StreamMoverImpl(source, sourceClient, sourceMonitor, target, targetClient, targetMonitor);
 
         moveStreams(streamChooser, streamMover, rebalanceConcurrency, rebalanceRateLimiter);
     }

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamChooser.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamChooser.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamChooser.java
index e0fcaf1..d92aef0 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamChooser.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamChooser.java
@@ -18,7 +18,7 @@
 package com.twitter.distributedlog.service.balancer;
 
 /**
- * Choose a stream to rebalance
+ * Choose a stream to rebalance.
  */
 public interface StreamChooser {
     /**

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamMover.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamMover.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamMover.java
index 6857560..6e4205b 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamMover.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamMover.java
@@ -17,10 +17,13 @@
  */
 package com.twitter.distributedlog.service.balancer;
 
+/**
+ * A stream mover to move streams between proxies.
+ */
 public interface StreamMover {
 
     /**
-     * Move given stream <i>streamName</i>
+     * Move given stream <i>streamName</i>.
      *
      * @param streamName
      *          stream name to move

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamMoverImpl.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamMoverImpl.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamMoverImpl.java
index 75df4ea..fc67fb2 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamMoverImpl.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/StreamMoverImpl.java
@@ -48,7 +48,7 @@ public class StreamMoverImpl implements StreamMover {
     }
 
     /**
-     * Move given stream <i>streamName</i>
+     * Move given stream <i>streamName</i>.
      *
      * @param streamName
      *          stream name to move

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/package-info.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/package-info.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/package-info.java
new file mode 100644
index 0000000..4ae8d44
--- /dev/null
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/balancer/package-info.java
@@ -0,0 +1,21 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+/**
+ * Balancer to move streams around to balance the traffic.
+ */
+package com.twitter.distributedlog.service.balancer;
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/config/DefaultStreamConfigProvider.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/config/DefaultStreamConfigProvider.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/config/DefaultStreamConfigProvider.java
index d612195..b45b798 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/config/DefaultStreamConfigProvider.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/config/DefaultStreamConfigProvider.java
@@ -25,34 +25,41 @@ import com.twitter.distributedlog.config.ConfigurationSubscription;
 import com.twitter.distributedlog.config.DynamicDistributedLogConfiguration;
 import com.twitter.distributedlog.config.FileConfigurationBuilder;
 import com.twitter.distributedlog.config.PropertiesConfigurationBuilder;
-import org.apache.commons.configuration.ConfigurationException;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import java.io.File;
 import java.net.MalformedURLException;
 import java.util.List;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
+import org.apache.commons.configuration.ConfigurationException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * For all streams return the same dynamic config based on configFile.
  */
 public class DefaultStreamConfigProvider implements StreamConfigProvider {
-    static final Logger LOG = LoggerFactory.getLogger(DefaultStreamConfigProvider.class);
+
+    private static final Logger LOG = LoggerFactory.getLogger(DefaultStreamConfigProvider.class);
 
     private final Optional<DynamicDistributedLogConfiguration> dynConf;
     private final ConfigurationSubscription confSub;
 
-    public DefaultStreamConfigProvider(String configFilePath, ScheduledExecutorService executorService, int reloadPeriod,
-                                       TimeUnit reloadUnit) throws ConfigurationException {
+    public DefaultStreamConfigProvider(String configFilePath,
+                                       ScheduledExecutorService executorService,
+                                       int reloadPeriod,
+                                       TimeUnit reloadUnit)
+        throws ConfigurationException {
         try {
             File configFile = new File(configFilePath);
-            FileConfigurationBuilder properties = new PropertiesConfigurationBuilder(configFile.toURI().toURL());
-            ConcurrentConstConfiguration defaultConf = new ConcurrentConstConfiguration(new DistributedLogConfiguration());
-            DynamicDistributedLogConfiguration conf = new DynamicDistributedLogConfiguration(defaultConf);
+            FileConfigurationBuilder properties =
+                new PropertiesConfigurationBuilder(configFile.toURI().toURL());
+            ConcurrentConstConfiguration defaultConf =
+                new ConcurrentConstConfiguration(new DistributedLogConfiguration());
+            DynamicDistributedLogConfiguration conf =
+                new DynamicDistributedLogConfiguration(defaultConf);
             List<FileConfigurationBuilder> fileConfigBuilders = Lists.newArrayList(properties);
-            confSub = new ConfigurationSubscription(conf, fileConfigBuilders, executorService, reloadPeriod, reloadUnit);
+            confSub = new ConfigurationSubscription(
+                conf, fileConfigBuilders, executorService, reloadPeriod, reloadUnit);
             this.dynConf = Optional.of(conf);
         } catch (MalformedURLException ex) {
             throw new ConfigurationException(ex);

http://git-wip-us.apache.org/repos/asf/incubator-distributedlog/blob/1a30b0ce/distributedlog-service/src/main/java/com/twitter/distributedlog/service/config/ServerConfiguration.java
----------------------------------------------------------------------
diff --git a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/config/ServerConfiguration.java b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/config/ServerConfiguration.java
index 5b19f6c..b3b4c4e 100644
--- a/distributedlog-service/src/main/java/com/twitter/distributedlog/service/config/ServerConfiguration.java
+++ b/distributedlog-service/src/main/java/com/twitter/distributedlog/service/config/ServerConfiguration.java
@@ -17,7 +17,8 @@
  */
 package com.twitter.distributedlog.service.config;
 
-import com.google.common.base.Preconditions;
+import static com.google.common.base.Preconditions.checkArgument;
+
 import com.twitter.distributedlog.DLSN;
 import com.twitter.distributedlog.DistributedLogConfiguration;
 import com.twitter.distributedlog.DistributedLogConstants;
@@ -29,7 +30,7 @@ import org.apache.commons.configuration.ConfigurationException;
 import org.apache.commons.configuration.SystemConfiguration;
 
 /**
- * Configuration for DistributedLog Server
+ * Configuration for DistributedLog Server.
  */
 public class ServerConfiguration extends CompositeConfiguration {
 
@@ -43,36 +44,36 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     // Server DLSN version
-    protected final static String SERVER_DLSN_VERSION = "server_dlsn_version";
-    protected final static byte SERVER_DLSN_VERSION_DEFAULT = DLSN.VERSION1;
+    protected static final String SERVER_DLSN_VERSION = "server_dlsn_version";
+    protected static final byte SERVER_DLSN_VERSION_DEFAULT = DLSN.VERSION1;
 
     // Server Durable Write Enable/Disable Flag
-    protected final static String SERVER_DURABLE_WRITE_ENABLED = "server_durable_write_enabled";
-    protected final static boolean SERVER_DURABLE_WRITE_ENABLED_DEFAULT = true;
+    protected static final String SERVER_DURABLE_WRITE_ENABLED = "server_durable_write_enabled";
+    protected static final boolean SERVER_DURABLE_WRITE_ENABLED_DEFAULT = true;
 
     // Server Region Id
-    protected final static String SERVER_REGION_ID = "server_region_id";
-    protected final static int SERVER_REGION_ID_DEFAULT = DistributedLogConstants.LOCAL_REGION_ID;
+    protected static final String SERVER_REGION_ID = "server_region_id";
+    protected static final int SERVER_REGION_ID_DEFAULT = DistributedLogConstants.LOCAL_REGION_ID;
 
     // Server Port
-    protected final static String SERVER_PORT = "server_port";
-    protected final static int SERVER_PORT_DEFAULT = 0;
+    protected static final String SERVER_PORT = "server_port";
+    protected static final int SERVER_PORT_DEFAULT = 0;
 
     // Server Shard Id
-    protected final static String SERVER_SHARD_ID = "server_shard";
-    protected final static int SERVER_SHARD_ID_DEFAULT = -1;
+    protected static final String SERVER_SHARD_ID = "server_shard";
+    protected static final int SERVER_SHARD_ID_DEFAULT = -1;
 
     // Server Threads
-    protected final static String SERVER_NUM_THREADS = "server_threads";
-    protected final static int SERVER_NUM_THREADS_DEFAULT = Runtime.getRuntime().availableProcessors();
+    protected static final String SERVER_NUM_THREADS = "server_threads";
+    protected static final int SERVER_NUM_THREADS_DEFAULT = Runtime.getRuntime().availableProcessors();
 
     // Server enable per stream stat
-    protected final static String SERVER_ENABLE_PERSTREAM_STAT = "server_enable_perstream_stat";
-    protected final static boolean SERVER_ENABLE_PERSTREAM_STAT_DEFAULT = true;
+    protected static final String SERVER_ENABLE_PERSTREAM_STAT = "server_enable_perstream_stat";
+    protected static final boolean SERVER_ENABLE_PERSTREAM_STAT_DEFAULT = true;
 
     // Server graceful shutdown period (in millis)
-    protected final static String SERVER_GRACEFUL_SHUTDOWN_PERIOD_MS = "server_graceful_shutdown_period_ms";
-    protected final static long SERVER_GRACEFUL_SHUTDOWN_PERIOD_MS_DEFAULT = 0L;
+    protected static final String SERVER_GRACEFUL_SHUTDOWN_PERIOD_MS = "server_graceful_shutdown_period_ms";
+    protected static final long SERVER_GRACEFUL_SHUTDOWN_PERIOD_MS_DEFAULT = 0L;
 
     // Server service timeout
     public static final String SERVER_SERVICE_TIMEOUT_MS = "server_service_timeout_ms";
@@ -86,17 +87,18 @@ public class ServerConfiguration extends CompositeConfiguration {
     // Server stream probation timeout
     public static final String SERVER_STREAM_PROBATION_TIMEOUT_MS = "server_stream_probation_timeout_ms";
     public static final String SERVER_STREAM_PROBATION_TIMEOUT_MS_OLD = "streamProbationTimeoutMs";
-    public static final long SERVER_STREAM_PROBATION_TIMEOUT_MS_DEFAULT = 60*1000*5;
+    public static final long SERVER_STREAM_PROBATION_TIMEOUT_MS_DEFAULT = 60 * 1000 * 5;
 
     // Server stream to partition converter
-    protected final static String SERVER_STREAM_PARTITION_CONVERTER_CLASS = "stream_partition_converter_class";
+    protected static final String SERVER_STREAM_PARTITION_CONVERTER_CLASS = "stream_partition_converter_class";
 
     // Use hostname as the allocator pool name
-    protected static final String SERVER_USE_HOSTNAME_AS_ALLOCATOR_POOL_NAME
-        = "server_use_hostname_as_allocator_pool_name";
+    protected static final String SERVER_USE_HOSTNAME_AS_ALLOCATOR_POOL_NAME =
+        "server_use_hostname_as_allocator_pool_name";
     protected static final boolean SERVER_USE_HOSTNAME_AS_ALLOCATOR_POOL_NAME_DEFAULT = false;
     //Configure refresh interval for calculating resource placement in seconds
-    public static final String SERVER_RESOURCE_PLACEMENT_REFRESH_INTERVAL_S = "server_resource_placement_refresh_interval_sec";
+    public static final String SERVER_RESOURCE_PLACEMENT_REFRESH_INTERVAL_S =
+        "server_resource_placement_refresh_interval_sec";
     public static final int  SERVER_RESOURCE_PLACEMENT_REFRESH_INTERVAL_DEFAULT = 120;
 
     public ServerConfiguration() {
@@ -105,7 +107,7 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Load configurations from {@link DistributedLogConfiguration}
+     * Load configurations from {@link DistributedLogConfiguration}.
      *
      * @param dlConf
      *          distributedlog configuration
@@ -137,7 +139,7 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Set the flag to enable/disable durable write
+     * Set the flag to enable/disable durable write.
      *
      * @param enabled
      *          flag to enable/disable durable write
@@ -149,7 +151,7 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Is durable write enabled?
+     * Is durable write enabled.
      *
      * @return true if waiting writes to be durable. otherwise false.
      */
@@ -158,7 +160,7 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Set the region id used to instantiate DistributedLogNamespace
+     * Set the region id used to instantiate DistributedLogNamespace.
      *
      * @param regionId
      *          region id
@@ -170,8 +172,7 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Get the region id used to instantiate
-     * {@link com.twitter.distributedlog.namespace.DistributedLogNamespace}
+     * Get the region id used to instantiate {@link com.twitter.distributedlog.namespace.DistributedLogNamespace}.
      *
      * @return region id used to instantiate DistributedLogNamespace
      */
@@ -213,8 +214,9 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Get the shard id of this server. It would be used to instantiate the client id
-     * used for DistributedLogNamespace.
+     * Get the shard id of this server.
+     *
+     * <p>It would be used to instantiate the client id used for DistributedLogNamespace.
      *
      * @return shard id of this server.
      */
@@ -286,7 +288,9 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Get timeout for stream op execution in proxy layer. 0 disables timeout.
+     * Get timeout for stream op execution in proxy layer.
+     *
+     * <p>0 disables timeout.
      *
      * @return timeout for stream operation in proxy layer.
      */
@@ -296,7 +300,9 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Set timeout for stream op execution in proxy layer. 0 disables timeout.
+     * Set timeout for stream op execution in proxy layer.
+     *
+     * <p>0 disables timeout.
      *
      * @param timeoutMs
      *          timeout for stream operation in proxy layer.
@@ -308,7 +314,9 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Get timeout for closing writer in proxy layer. 0 disables timeout.
+     * Get timeout for closing writer in proxy layer.
+     *
+     * <p>0 disables timeout.
      *
      * @return timeout for closing writer in proxy layer.
      */
@@ -317,7 +325,9 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Set timeout for closing writer in proxy layer. 0 disables timeout.
+     * Set timeout for closing writer in proxy layer.
+     *
+     * <p>0 disables timeout.
      *
      * @param timeoutMs
      *          timeout for closing writer in proxy layer.
@@ -329,8 +339,9 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * After service timeout, how long should stream be kept in cache in probationary state in order
-     * to prevent reacquire. In millisec.
+     * How long should stream be kept in cache in probationary state after service timeout.
+     *
+     * <p>The setting is to prevent reacquire. The unit of this setting is milliseconds.
      *
      * @return stream probation timeout in ms.
      */
@@ -340,10 +351,12 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * After service timeout, how long should stream be kept in cache in probationary state in order
-     * to prevent reacquire. In millisec.
+     * How long should stream be kept in cache in probationary state after service timeout.
+     *
+     * <p>The setting is to prevent reacquire. The unit of this setting is milliseconds.
      *
      * @param timeoutMs probation timeout in ms.
+     * @return server configuration
      */
     public ServerConfiguration setStreamProbationTimeoutMs(long timeoutMs) {
         setProperty(SERVER_STREAM_PROBATION_TIMEOUT_MS, timeoutMs);
@@ -357,7 +370,8 @@ public class ServerConfiguration extends CompositeConfiguration {
      *          stream partition converter class
      * @return server configuration
      */
-    public ServerConfiguration setStreamPartitionConverterClass(Class<? extends StreamPartitionConverter> converterClass) {
+    public ServerConfiguration setStreamPartitionConverterClass(
+        Class<? extends StreamPartitionConverter> converterClass) {
         setProperty(SERVER_STREAM_PARTITION_CONVERTER_CLASS, converterClass.getName());
         return this;
     }
@@ -391,7 +405,7 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Get if use hostname as the allocator pool name
+     * Get if use hostname as the allocator pool name.
      *
      * @return true if use hostname as the allocator pool name. otherwise, use
      * {@link #getServerShardId()} as the allocator pool name.
@@ -412,15 +426,17 @@ public class ServerConfiguration extends CompositeConfiguration {
     }
 
     /**
-     * Validate the configuration
+     * Validate the configuration.
+     *
+     * @throws IllegalStateException when there are any invalid settings.
      */
     public void validate() {
         byte dlsnVersion = getDlsnVersion();
-        Preconditions.checkArgument(dlsnVersion >= DLSN.VERSION0 && dlsnVersion <= DLSN.VERSION1,
+        checkArgument(dlsnVersion >= DLSN.VERSION0 && dlsnVersion <= DLSN.VERSION1,
                 "Unknown dlsn version " + dlsnVersion);
-        Preconditions.checkArgument(getServerThreads() > 0,
+        checkArgument(getServerThreads() > 0,
                 "Invalid number of server threads : " + getServerThreads());
-        Preconditions.checkArgument(getServerShardId() >= 0,
+        checkArgument(getServerShardId() >= 0,
                 "Invalid server shard id : " + getServerShardId());
     }
 



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