Merge pull request XRPLF#125 from ankgup87/master

[Java] Add bloom filter JNI bindings

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 org.rocksdb.BackupableDB org.rocksdb.BackupableDBOptions org.rocksdb.Statistics org.rocksdb.Iterator org.rocksdb.VectorMemTableConfig org.rocksdb.SkipListMemTableConfig org.rocksdb.HashLinkedListMemTableConfig org.rocksdb.HashSkipListMemTableConfig org.rocksdb.PlainTableConfig org.rocksdb.ReadOptions
+NATIVE_JAVA_CLASSES = org.rocksdb.RocksDB org.rocksdb.Options org.rocksdb.WriteBatch org.rocksdb.WriteBatchInternal org.rocksdb.WriteBatchTest org.rocksdb.WriteOptions org.rocksdb.BackupableDB org.rocksdb.BackupableDBOptions org.rocksdb.Statistics org.rocksdb.Iterator org.rocksdb.VectorMemTableConfig org.rocksdb.SkipListMemTableConfig org.rocksdb.HashLinkedListMemTableConfig org.rocksdb.HashSkipListMemTableConfig org.rocksdb.PlainTableConfig org.rocksdb.ReadOptions org.rocksdb.Filter org.rocksdb.BloomFilter
 NATIVE_INCLUDE = ./include
 ROCKSDB_JAR = rocksdbjni.jar
 

java/RocksDBSample.java

@@ -32,13 +32,15 @@ public static void main(String[] args) {
       assert(db == null);
     }
 
+    Filter filter = new BloomFilter(10);
     options.setCreateIfMissing(true)
         .createStatistics()
         .setWriteBufferSize(8 * SizeUnit.KB)
         .setMaxWriteBufferNumber(3)
         .setDisableSeekCompaction(true)
         .setBlockSize(64 * SizeUnit.KB)
-        .setMaxBackgroundCompactions(10);
+        .setMaxBackgroundCompactions(10)
+        .setFilter(filter);
     Statistics stats = options.statisticsPtr();
 
     assert(options.createIfMissing() == true);
@@ -224,5 +226,6 @@ public static void main(String[] args) {
     // be sure to dispose c++ pointers
     options.dispose();
     readOptions.dispose();
+    filter.dispose();
   }
 }

java/org/rocksdb/BloomFilter.java

@@ -0,0 +1,37 @@
+// Copyright (c) 2014, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+
+package org.rocksdb;
+
+/**
+ * This class creates a new filter policy that uses a bloom filter
+ * with approximately the specified number of bits per key.
+ * A good value for bitsPerKey is 10, which yields a filter
+ * with ~ 1% false positive rate.
+ *
+ * Default value of bits per key is 10.
+ */
+public class BloomFilter extends Filter {
+  private static final int DEFAULT_BITS_PER_KEY = 10;
+  private final int bitsPerKey_;
+
+  public BloomFilter() {
+    this(DEFAULT_BITS_PER_KEY);
+  }
+
+  public BloomFilter(int bitsPerKey) {
+    super();
+    bitsPerKey_ = bitsPerKey;
+
+    createNewFilter();
+  }
+
+  @Override
+  protected void createNewFilter() {
+    createNewFilter0(bitsPerKey_);
+  }
+
+  private native void createNewFilter0(int bitsKeyKey);
+}

java/org/rocksdb/Filter.java

@@ -0,0 +1,38 @@
+// Copyright (c) 2014, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+
+package org.rocksdb;
+
+/**
+ * Filters are stored in rocksdb and are consulted automatically
+ * by rocksdb to decide whether or not to read some
+ * information from disk. In many cases, a filter can cut down the
+ * number of disk seeks form a handful to a single disk seek per
+ * DB::Get() call.
+ */
+public abstract class Filter {
+  protected long nativeHandle_ = 0;
+
+  protected abstract void createNewFilter();
+
+  /**
+   * Deletes underlying C++ filter pointer.
+   */
+  public synchronized void dispose() {
+    if(nativeHandle_ != 0) {
+      dispose0(nativeHandle_);
+    }
+  }
+
+  @Override protected void finalize() {
+    dispose();
+  }
+
+  protected boolean isInitialized() {
+    return (nativeHandle_ != 0);
+  }
+
+  private native void dispose0(long handle);
+}

java/org/rocksdb/Options.java

@@ -144,6 +144,18 @@ public long blockSize() {
     return blockSize(nativeHandle_);
   }
 
+  /**
+   * Use the specified filter policy to reduce disk reads.
+   * @param Filter policy java instance.
+   * @return the instance of the current Options.
+   * @see RocksDB.open()
+   */
+  public Options setFilter(Filter filter) {
+    assert(isInitialized());
+    setFilter0(nativeHandle_, filter);
+    return this;
+  }
+
   /*
    * Disable compaction triggered by seek.
    * With bloomfilter and fast storage, a miss on one level
@@ -1238,6 +1250,8 @@ private native void setMaxBackgroundCompactions(
   private native void useFixedLengthPrefixExtractor(
       long handle, int prefixLength);
 
+  private native void setFilter0(long optHandle, Filter fp);
+
   long nativeHandle_;
   long cacheSize_;
 }

java/org/rocksdb/ReadOptions.java

@@ -162,4 +162,3 @@ private boolean isInitialized() {
     return nativeHandle_ != 0;
   }
 }
-

java/rocksjni/filter.cc

@@ -0,0 +1,41 @@
+// Copyright (c) 2014, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+//
+// This file implements the "bridge" between Java and C++ for
+// rocksdb::FilterPolicy.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <jni.h>
+#include <string>
+
+#include "include/org_rocksdb_Filter.h"
+#include "include/org_rocksdb_BloomFilter.h"
+#include "rocksjni/portal.h"
+#include "rocksdb/filter_policy.h"
+
+/*
+ * Class:     org_rocksdb_BloomFilter
+ * Method:    createNewFilter0
+ * Signature: (I)V
+ */
+void Java_org_rocksdb_BloomFilter_createNewFilter0(
+    JNIEnv* env, jobject jobj, jint bits_per_key) {
+  const rocksdb::FilterPolicy* fp = rocksdb::NewBloomFilterPolicy(bits_per_key);
+  rocksdb::FilterJni::setHandle(env, jobj, fp);
+}
+
+/*
+ * Class:     org_rocksdb_Filter
+ * Method:    dispose0
+ * Signature: (J)V
+ */
+void Java_org_rocksdb_Filter_dispose0(
+    JNIEnv* env, jobject jobj, jlong handle) {
+  auto fp = reinterpret_cast<rocksdb::FilterPolicy*>(handle);
+  delete fp;
+
+  rocksdb::FilterJni::setHandle(env, jobj, nullptr);
+}

java/rocksjni/options.cc

@@ -21,6 +21,7 @@
 #include "rocksdb/memtablerep.h"
 #include "rocksdb/table.h"
 #include "rocksdb/slice_transform.h"
+#include "rocksdb/filter_policy.h"
 
 /*
  * Class:     org_rocksdb_Options
@@ -119,6 +120,17 @@ jlong Java_org_rocksdb_Options_statisticsPtr(
   return reinterpret_cast<jlong>(st);
 }
 
+/*
+ * Class:     org_rocksdb_Options
+ * Method:    setFilter0
+ * Signature: (JJ)V
+ */
+void Java_org_rocksdb_Options_setFilter0(
+    JNIEnv* env, jobject jobj, jlong jopt_handle, jobject jfp) {
+  reinterpret_cast<rocksdb::Options*>(jopt_handle)->filter_policy =
+      rocksdb::FilterJni::getHandle(env, jfp);
+}
+
 /*
  * Class:     org_rocksdb_Options
  * Method:    maxWriteBufferNumber

java/rocksjni/portal.h

@@ -12,6 +12,7 @@
 
 #include <jni.h>
 #include "rocksdb/db.h"
+#include "rocksdb/filter_policy.h"
 #include "utilities/backupable_db.h"
 
 namespace rocksdb {
@@ -281,5 +282,38 @@ class IteratorJni {
         reinterpret_cast<jlong>(op));
   }
 };
+
+class FilterJni {
+ public:
+  // Get the java class id of org.rocksdb.FilterPolicy.
+  static jclass getJClass(JNIEnv* env) {
+    static jclass jclazz = env->FindClass("org/rocksdb/Filter");
+    assert(jclazz != nullptr);
+    return jclazz;
+  }
+
+  // Get the field id of the member variable of org.rocksdb.Filter
+  // that stores the pointer to rocksdb::FilterPolicy.
+  static jfieldID getHandleFieldID(JNIEnv* env) {
+    static jfieldID fid = env->GetFieldID(
+        getJClass(env), "nativeHandle_", "J");
+    assert(fid != nullptr);
+    return fid;
+  }
+
+  // Get the pointer to rocksdb::FilterPolicy.
+  static rocksdb::FilterPolicy* getHandle(JNIEnv* env, jobject jobj) {
+    return reinterpret_cast<rocksdb::FilterPolicy*>(
+        env->GetLongField(jobj, getHandleFieldID(env)));
+  }
+
+  // Pass the rocksdb::FilterPolicy pointer to the java side.
+  static void setHandle(
+      JNIEnv* env, jobject jobj, const rocksdb::FilterPolicy* op) {
+    env->SetLongField(
+        jobj, getHandleFieldID(env),
+        reinterpret_cast<jlong>(op));
+  }
+};
 }  // namespace rocksdb
 #endif  // JAVA_ROCKSJNI_PORTAL_H_