From 1470b37193abf9ce28c7f75a8713c47fa5907d0e Mon Sep 17 00:00:00 2001
From: elcallio <calle@wilund.net>
Date: Tue, 11 Oct 2016 14:05:15 +0200
Subject: [PATCH] Rework CommitLog

---
 .../cassandra/db/commitlog/CommitLog.java     | 48 +++++++------------
 1 file changed, 16 insertions(+), 32 deletions(-)

diff --git a/src/main/java/org/apache/cassandra/db/commitlog/CommitLog.java b/src/main/java/org/apache/cassandra/db/commitlog/CommitLog.java
index e943351..bc041ef 100644
--- a/src/main/java/org/apache/cassandra/db/commitlog/CommitLog.java
+++ b/src/main/java/org/apache/cassandra/db/commitlog/CommitLog.java
@@ -23,7 +23,6 @@
 package org.apache.cassandra.db.commitlog;
 
 import java.io.IOException;
-import java.lang.management.ManagementFactory;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -31,48 +30,31 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
-import javax.management.MBeanServer;
-import javax.management.ObjectName;
-
 import org.apache.cassandra.metrics.CommitLogMetrics;
 
 import com.scylladb.jmx.api.APIClient;
+import com.scylladb.jmx.metrics.MetricsMBean;
 
 /*
  * Commit Log tracks every write operation into the system. The aim of the commit log is to be able to
  * successfully recover data that was not stored to disk via the Memtable.
  */
-public class CommitLog implements CommitLogMBean {
-
-    CommitLogMetrics metrics = new CommitLogMetrics();
+public class CommitLog extends MetricsMBean implements CommitLogMBean {
     private static final java.util.logging.Logger logger = java.util.logging.Logger
             .getLogger(CommitLog.class.getName());
 
-    private APIClient c = new APIClient();
-
     public void log(String str) {
         logger.finest(str);
     }
 
-    private static final CommitLog instance = new CommitLog();
-
-    public static CommitLog getInstance() {
-        return instance;
-    }
-
-    private CommitLog() {
-        MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
-        try {
-            mbs.registerMBean(this,
-                    new ObjectName("org.apache.cassandra.db:type=Commitlog"));
-        } catch (Exception e) {
-            throw new RuntimeException(e);
-        }
+    public CommitLog(APIClient client) {
+        super("org.apache.cassandra.db:type=Commitlog", client, new CommitLogMetrics());
     }
 
     /**
      * Recover a single file.
      */
+    @Override
     public void recover(String path) throws IOException {
         log(" recover(String path) throws IOException");
     }
@@ -81,9 +63,10 @@ public class CommitLog implements CommitLogMBean {
      * @return file names (not full paths) of active commit log segments
      *         (segments containing unflushed data)
      */
+    @Override
     public List<String> getActiveSegmentNames() {
         log(" getActiveSegmentNames()");
-        List<String> lst = c.getListStrValue("/commitlog/segments/active");
+        List<String> lst = client.getListStrValue("/commitlog/segments/active");
         Set<String> set = new HashSet<String>();
         for (String l : lst) {
             String name = l.substring(l.lastIndexOf("/") + 1, l.length());
@@ -96,9 +79,10 @@ public class CommitLog implements CommitLogMBean {
      * @return Files which are pending for archival attempt. Does NOT include
      *         failed archive attempts.
      */
+    @Override
     public List<String> getArchivingSegmentNames() {
         log(" getArchivingSegmentNames()");
-        List<String> lst = c.getListStrValue("/commitlog/segments/archiving");
+        List<String> lst = client.getListStrValue("/commitlog/segments/archiving");
         Set<String> set = new HashSet<String>();
         for (String l : lst) {
             String name = l.substring(l.lastIndexOf("/") + 1, l.length());
@@ -111,46 +95,46 @@ public class CommitLog implements CommitLogMBean {
     public String getArchiveCommand() {
         // TODO Auto-generated method stub
         log(" getArchiveCommand()");
-        return c.getStringValue("");
+        return client.getStringValue("");
     }
 
     @Override
     public String getRestoreCommand() {
         // TODO Auto-generated method stub
         log(" getRestoreCommand()");
-        return c.getStringValue("");
+        return client.getStringValue("");
     }
 
     @Override
     public String getRestoreDirectories() {
         // TODO Auto-generated method stub
         log(" getRestoreDirectories()");
-        return c.getStringValue("");
+        return client.getStringValue("");
     }
 
     @Override
     public long getRestorePointInTime() {
         // TODO Auto-generated method stub
         log(" getRestorePointInTime()");
-        return c.getLongValue("");
+        return client.getLongValue("");
     }
 
     @Override
     public String getRestorePrecision() {
         // TODO Auto-generated method stub
         log(" getRestorePrecision()");
-        return c.getStringValue("");
+        return client.getStringValue("");
     }
 
     @Override
     public long getActiveContentSize() {
-        // scylla does not compress commit log, so this is equivalent 
+        // scylla does not compress commit log, so this is equivalent
         return getActiveOnDiskSize();
     }
 
     @Override
     public long getActiveOnDiskSize() {
-        return c.getLongValue("/commitlog/metrics/total_commit_log_size");
+        return client.getLongValue("/commitlog/metrics/total_commit_log_size");
     }
 
     @Override