Expose data dirs to ColumnFamilyStoreMBean

Patch by Stefan Miklosovic; reviewed by marcuse for CASSANDRA-16335

CHANGES.txt

@@ -1,4 +1,5 @@
 4.0-beta5
+ * Expose data dirs to ColumnFamilyStoreMBean (CASSANDRA-16335)
  * Add possibility to copy SSTables in SSTableImporter instead of moving them (CASSANDRA-16407)
  * Fix DESCRIBE statement for CUSTOM indices with options (CASSANDRA-16482)
  * Fix cassandra-stress JMX connection (CASSANDRA-16473)

src/java/org/apache/cassandra/db/ColumnFamilyStore.java

@@ -495,6 +495,17 @@ public class ColumnFamilyStore implements ColumnFamilyStoreMBean
         return directories;
     }
 
+    public List<String> getDataPaths() throws IOException
+    {
+        List<String> dataPaths = new ArrayList<>();
+        for (File dataPath : directories.getCFDirectories())
+        {
+            dataPaths.add(dataPath.getCanonicalPath());
+        }
+
+        return dataPaths;
+    }
+
     public SSTableMultiWriter createSSTableMultiWriter(Descriptor descriptor, long keyCount, long repairedAt, UUID pendingRepair, boolean isTransient, int sstableLevel, SerializationHeader header, LifecycleNewTracker lifecycleNewTracker)
     {
         MetadataCollector collector = new MetadataCollector(metadata().comparator).sstableLevel(sstableLevel);

src/java/org/apache/cassandra/db/ColumnFamilyStoreMBean.java

@@ -17,6 +17,7 @@
  */
 package org.apache.cassandra.db;
 
+import java.io.IOException;
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
@@ -248,4 +249,6 @@ public interface ColumnFamilyStoreMBean
      *         If all SSTables are correctly placed or the partitioner does not support splitting, it returns false.
      */
     public boolean hasMisplacedSSTables();
+
+    public List<String> getDataPaths() throws IOException;
 }

test/unit/org/apache/cassandra/db/ColumnFamilyStoreTest.java

@@ -22,8 +22,11 @@ import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
 import java.nio.ByteBuffer;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.*;
 
+import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Assume;
 import org.junit.BeforeClass;
@@ -458,6 +461,22 @@ public class ColumnFamilyStoreTest
         assert indexTableFile.endsWith(baseTableFile);
     }
 
+    @Test
+    public void testDataDirectoriesOfColumnFamily() throws Exception
+    {
+        ColumnFamilyStore cfs = Keyspace.open(KEYSPACE1).getColumnFamilyStore(CF_STANDARD1);
+        List<String> dataPaths = cfs.getDataPaths();
+        Assert.assertFalse(dataPaths.isEmpty());
+
+        Path path = Paths.get(dataPaths.get(0));
+
+        String keyspace = path.getParent().getFileName().toString();
+        String table = path.getFileName().toString().split("-")[0];
+
+        Assert.assertEquals(cfs.getTableName(), table);
+        Assert.assertEquals(KEYSPACE1, keyspace);
+    }
+
     @Test
     public void testScrubDataDirectories() throws Throwable
     {