Add statistics object

java/Makefile

@@ -1,4 +1,4 @@
-NATIVE_JAVA_CLASSES = org.rocksdb.RocksDB org.rocksdb.Options org.rocksdb.WriteBatch org.rocksdb.WriteBatchInternal org.rocksdb.WriteBatchTest org.rocksdb.WriteOptions
+NATIVE_JAVA_CLASSES = org.rocksdb.RocksDB org.rocksdb.Options org.rocksdb.WriteBatch org.rocksdb.WriteBatchInternal org.rocksdb.WriteBatchTest org.rocksdb.WriteOptions org.rocksdb.Statistics
 NATIVE_INCLUDE = ./include
 ROCKSDB_JAR = rocksdbjni.jar
 

java/RocksDBSample.java

@@ -34,11 +34,13 @@ public class RocksDBSample {
     }
 
     options.setCreateIfMissing(true)
+        .createStatistics()
         .setWriteBufferSize(8 * SizeUnit.KB)
         .setMaxWriteBufferNumber(3)
         .setDisableSeekCompaction(true)
         .setBlockSize(64 * SizeUnit.KB)
         .setMaxBackgroundCompactions(10);
+    Statistics stats = new Statistics(options.statisticsPtr());
 
     assert(options.createIfMissing() == true);
     assert(options.writeBufferSize() == 8 * SizeUnit.KB);
@@ -120,13 +122,25 @@ public class RocksDBSample {
       assert(new String(testValue).equals(
           new String(enoughArray, 0, len)));
       writeOpts.dispose();
+
+      try {
+        for(StatisticsType statsType : StatisticsType.values()) {
+          stats.getTickerCount(statsType);
+        }
+        System.out.println("getTickerCount() passed.");
+      }
+      catch(Exception e) {
+        System.out.println("Failed in call to getTickerCount()");
+        assert(false); //Should never reach here.
+      }
+
     } catch (RocksDBException e) {
       System.err.println(e);
     }
     if (db != null) {
       db.close();
     }
-    // be sure to dispose c++ pointer
+    // be sure to dispose c++ pointers
     options.dispose();
   }
 }

java/org/rocksdb/Options.java

@@ -200,6 +200,35 @@ public class Options {
     return maxBackgroundCompactions(nativeHandle_);
   }
 
+  /*
+   * Creates statistics object which collects metrics about database operations.
+     Statistics objects should not be shared between DB instances as
+     it does not use any locks to prevent concurrent updates.
+   *
+   * @return the instance of the current Options.
+   * @see RocksDB.open()
+   */
+  public Options createStatistics() {
+    assert(isInitialized());
+    createStatistics(nativeHandle_);
+    return this;
+  }
+
+  /*
+   * Pointer to statistics object. Should only be called after statistics has
+   * been created by createStatistics() call.
+   *
+   * @see createStatistics()
+   */
+  public long statisticsPtr() {
+    assert(isInitialized());
+
+    long statsPtr = statisticsPtr(nativeHandle_);
+    assert(statsPtr != 0);
+
+    return statsPtr;
+  }
+
   /**
    * Set the amount of cache in bytes that will be used by RocksDB.
    * If cacheSize is non-positive, then cache will not be used.
@@ -223,7 +252,7 @@ public class Options {
    * in the c++ side.
    */
   public synchronized void dispose() {
-    if (nativeHandle_ != 0) {
+    if (isInitialized()) {
       dispose0();
     }
   }
@@ -249,6 +278,8 @@ public class Options {
   private native void setMaxBackgroundCompactions(
       long handle, int maxBackgroundCompactions);
   private native int maxBackgroundCompactions(long handle);
+  private native void createStatistics(long optHandle);
+  private native long statisticsPtr(long optHandle);
 
   long nativeHandle_;
   long cacheSize_;

java/org/rocksdb/RocksDB.java

@@ -5,7 +5,6 @@
 
 package org.rocksdb;
 
-import java.lang.*;
 import java.util.*;
 import java.io.Closeable;
 import java.io.IOException;

java/org/rocksdb/RocksDBException.java

@@ -5,7 +5,6 @@
 
 package org.rocksdb;
 
-import java.lang.*;
 import java.util.*;
 
 /**

java/org/rocksdb/WriteBatch.java

@@ -5,7 +5,6 @@
 
 package org.rocksdb;
 
-import java.lang.*;
 import java.util.*;
 
 /**
@@ -118,4 +117,3 @@ class WriteBatchInternal {
   static native long sequence(WriteBatch batch);
   static native void append(WriteBatch b1, WriteBatch b2);
 }
-

java/org/rocksdb/WriteBatchTest.java

@@ -9,7 +9,6 @@
 package org.rocksdb;
 
 import java.util.*;
-import java.lang.*;
 import java.io.UnsupportedEncodingException;
 
 /**

java/rocksjni/options.cc

@@ -9,12 +9,14 @@
 #include <stdlib.h>
 #include <jni.h>
 #include <string>
+#include <memory>
 
 #include "include/org_rocksdb_Options.h"
 #include "include/org_rocksdb_WriteOptions.h"
 #include "rocksjni/portal.h"
 #include "rocksdb/db.h"
 #include "rocksdb/options.h"
+#include "rocksdb/statistics.h"
 
 /*
  * Class:     org_rocksdb_Options
@@ -35,7 +37,7 @@ void Java_org_rocksdb_Options_dispose0(JNIEnv* env, jobject jobj) {
   rocksdb::Options* op = rocksdb::OptionsJni::getHandle(env, jobj);
   delete op;
 
-  rocksdb::OptionsJni::setHandle(env, jobj, op);
+  rocksdb::OptionsJni::setHandle(env, jobj, nullptr);
 }
 
 /*
@@ -91,6 +93,27 @@ void Java_org_rocksdb_Options_setMaxWriteBufferNumber(
           jmax_write_buffer_number;
 }
 
+/*
+ * Class:     org_rocksdb_Options
+ * Method:    createStatistics
+ * Signature: (J)V
+ */
+void Java_org_rocksdb_Options_createStatistics(
+    JNIEnv* env, jobject jobj, jlong jOptHandle) {
+  reinterpret_cast<rocksdb::Options*>(jOptHandle)->statistics =
+      rocksdb::CreateDBStatistics();
+}
+
+/*
+ * Class:     org_rocksdb_Options
+ * Method:    statisticsPtr
+ * Signature: (J)J
+ */
+jlong Java_org_rocksdb_Options_statisticsPtr(
+    JNIEnv* env, jobject jobj, jlong jOptHandle) {
+  auto st = reinterpret_cast<rocksdb::Options*>(jOptHandle)->statistics.get();
+  return reinterpret_cast<jlong>(st);
+}
 
 /*
  * Class:     org_rocksdb_Options
@@ -235,5 +258,3 @@ jboolean Java_org_rocksdb_WriteOptions_disableWAL(
     JNIEnv* env, jobject jwrite_options, jlong jhandle) {
   return reinterpret_cast<rocksdb::WriteOptions*>(jhandle)->disableWAL;
 }
-
-

java/rocksjni/portal.h

@@ -12,6 +12,7 @@
 
 #include <jni.h>
 #include "rocksdb/db.h"
+#include "rocksdb/statistics.h"
 
 namespace rocksdb {
 

java/rocksjni/write_batch.cc

@@ -262,4 +262,3 @@ jbyteArray Java_org_rocksdb_WriteBatchTest_getContents(
 
   return jstate;
 }
-