Change filter implementation

java/rocksjni/filter.cc

@@ -0,0 +1,39 @@
+// 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::Filter.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <jni.h>
+#include <string>
+
+#include "include/org_rocksdb_Filter.h"
+#include "rocksjni/portal.h"
+#include "rocksdb/filter_policy.h"
+
+/*
+ * Class:     org_rocksdb_Filter
+ * Method:    newFilter
+ * Signature: (I)V
+ */
+void Java_org_rocksdb_Filter_newFilter(
+    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

@@ -122,19 +122,13 @@ jlong Java_org_rocksdb_Options_statisticsPtr(
 
 /*
  * Class:     org_rocksdb_Options
- * Method:    createBloomFilter0
- * Signature: (JI)V
+ * Method:    setFilter0
+ * Signature: (JJ)V
  */
-void Java_org_rocksdb_Options_createBloomFilter0(
-    JNIEnv* env, jobject jobj, jlong jhandle, jint jbits_per_key) {
-  rocksdb::Options* opt = reinterpret_cast<rocksdb::Options*>(jhandle);
-
-  // Delete previously allocated pointer
-  if(opt->filter_policy) {
-    delete opt->filter_policy;
-  }
-
-  opt->filter_policy = rocksdb::NewBloomFilterPolicy(jbits_per_key);
+void Java_org_rocksdb_Options_setFilter0(
+    JNIEnv* env, jobject jobj, jlong jopt_handle, jlong jfp_handle) {
+  reinterpret_cast<rocksdb::Options*>(jopt_handle)->filter_policy =
+      reinterpret_cast<rocksdb::FilterPolicy*>(jfp_handle);
 }
 
 /*

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.Filter.
+  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::Iterator.
+  static jfieldID getHandleFieldID(JNIEnv* env) {
+    static jfieldID fid = env->GetFieldID(
+        getJClass(env), "nativeHandle_", "J");
+    assert(fid != nullptr);
+    return fid;
+  }
+
+  // Get the pointer to rocksdb::Filter.
+  static rocksdb::FilterPolicy* getHandle(JNIEnv* env, jobject jobj) {
+    return reinterpret_cast<rocksdb::FilterPolicy*>(
+        env->GetLongField(jobj, getHandleFieldID(env)));
+  }
+
+  // Pass the rocksdb::Filter 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_