Javadoc improvements

@@ -15,6 +15,9 @@ import org.onlab.onos.store.service.DatabaseException;
 import org.onlab.onos.store.service.ReadRequest;
 import org.onlab.onos.store.service.WriteRequest;
 
+/**
+ * Client for interacting with the Copycat Raft cluster.
+ */
 public class DatabaseClient {
 
     private final ProtocolClient client;

@@ -19,6 +19,13 @@ import org.onlab.util.KryoNamespace;
 
 import com.google.common.collect.Maps;
 
+/**
+ * StateMachine whose transitions are coordinated/replicated
+ * by Raft consensus.
+ * Each Raft cluster member has a instance of this state machine that is
+ * independently updated in lock step once there is consensus
+ * on the next transition.
+ */
 public class DatabaseStateMachine implements StateMachine {
 
     public static final KryoSerializer SERIALIZER = new KryoSerializer() {

@@ -2,6 +2,9 @@ package org.onlab.onos.store.service.impl;
 
 import org.onlab.onos.store.service.ReadResult;
 
+/**
+ * Result of a read operation executed on the DatabaseStateMachine.
+ */
 public class InternalReadResult {
 
     public enum Status {

@@ -2,6 +2,9 @@ package org.onlab.onos.store.service.impl;
 
 import org.onlab.onos.store.service.WriteResult;
 
+/**
+ * Result of a write operation executed on the DatabaseStateMachine.
+ */
 public class InternalWriteResult {
 
     public enum Status {