Refactor filter impl

java/org/rocksdb/Filter.java

@@ -12,7 +12,7 @@ package org.rocksdb;
  * number of disk seeks form a handful to a single disk seek per
  * DB::Get() call.
  *
- * This function a new filter policy that uses a bloom filter
+ * 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.
@@ -24,10 +24,6 @@ public class Filter {
     newFilter(bitsPerKey);
   }
 
-  public long getNativeHandle() {
-    return nativeHandle_;
-  }
-  
   /**
    * Deletes underlying C++ filter pointer.
    */

java/org/rocksdb/Options.java

@@ -152,7 +152,7 @@ public class Options {
    */
   public Options setFilter(Filter filter) {
     assert(isInitialized());
-    setFilter0(nativeHandle_, filter.getNativeHandle());
+    setFilter0(nativeHandle_, filter);
     return this;
   }
 
@@ -1250,7 +1250,7 @@ public class Options {
   private native void useFixedLengthPrefixExtractor(
       long handle, int prefixLength);
 
-  private native void setFilter0(long optHandle, long fpHandle);
+  private native void setFilter0(long optHandle, Filter fp);
 
   long nativeHandle_;
   long cacheSize_;

java/rocksjni/options.cc

@@ -126,9 +126,9 @@ jlong Java_org_rocksdb_Options_statisticsPtr(
  * Signature: (JJ)V
  */
 void Java_org_rocksdb_Options_setFilter0(
-    JNIEnv* env, jobject jobj, jlong jopt_handle, jlong jfp_handle) {
+    JNIEnv* env, jobject jobj, jlong jopt_handle, jobject jfp) {
   reinterpret_cast<rocksdb::Options*>(jopt_handle)->filter_policy =
-      reinterpret_cast<rocksdb::FilterPolicy*>(jfp_handle);
+      rocksdb::FilterJni::getHandle(env, jfp);
 }
 
 /*