rocksdb/java/rocksjni/comparator.cc
Adam Retter c5302a8a58 Java wrapper for Native Comparators
Summary:
This is an abstraction for working with custom Comparators implemented in native C++ code from Java. Native code must directly extend `rocksdb::Comparator`. When the native code comparator is compiled into the RocksDB codebase, you can then create a Java Class, and JNI stub to wrap it.

Useful if the C++/JNI barrier overhead is too much for your applications comparator performance.

An example is provided in `java/rocksjni/native_comparator_wrapper_test.cc` and `java/src/main/java/org/rocksdb/NativeComparatorWrapperTest.java`.
Closes https://github.com/facebook/rocksdb/pull/3334

Differential Revision: D7172605

Pulled By: miasantreble

fbshipit-source-id: e24b7eb267a3bcb6afa214e0379a1d5e8a2ceabe
2018-03-08 11:27:42 -08:00

66 lines
1.9 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// This file implements the "bridge" between Java and C++ for
// rocksdb::Comparator.
#include <stdio.h>
#include <stdlib.h>
#include <jni.h>
#include <string>
#include <functional>
#include "include/org_rocksdb_Comparator.h"
#include "include/org_rocksdb_DirectComparator.h"
#include "include/org_rocksdb_NativeComparatorWrapper.h"
#include "rocksjni/comparatorjnicallback.h"
#include "rocksjni/portal.h"
// <editor-fold desc="org.rocksdb.Comparator>
/*
* Class: org_rocksdb_Comparator
* Method: createNewComparator0
* Signature: ()J
*/
jlong Java_org_rocksdb_Comparator_createNewComparator0(
JNIEnv* env, jobject jobj, jlong copt_handle) {
auto* copt =
reinterpret_cast<rocksdb::ComparatorJniCallbackOptions*>(copt_handle);
auto* c =
new rocksdb::ComparatorJniCallback(env, jobj, copt);
return reinterpret_cast<jlong>(c);
}
// </editor-fold>
// <editor-fold desc="org.rocksdb.DirectComparator>
/*
* Class: org_rocksdb_DirectComparator
* Method: createNewDirectComparator0
* Signature: ()J
*/
jlong Java_org_rocksdb_DirectComparator_createNewDirectComparator0(
JNIEnv* env, jobject jobj, jlong copt_handle) {
auto* copt =
reinterpret_cast<rocksdb::ComparatorJniCallbackOptions*>(copt_handle);
auto* c =
new rocksdb::DirectComparatorJniCallback(env, jobj, copt);
return reinterpret_cast<jlong>(c);
}
/*
* Class: org_rocksdb_NativeComparatorWrapper
* Method: disposeInternal
* Signature: (J)V
*/
void Java_org_rocksdb_NativeComparatorWrapper_disposeInternal(
JNIEnv* env, jobject jobj, jlong jcomparator_handle) {
auto* comparator =
reinterpret_cast<rocksdb::Comparator*>(jcomparator_handle);
delete comparator;
}
// </editor-fold>