c5302a8a58
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
51 lines
1.4 KiB
C++
51 lines
1.4 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#include <jni.h>
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#include <string>
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#include "rocksdb/comparator.h"
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#include "rocksdb/slice.h"
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#include "include/org_rocksdb_NativeComparatorWrapperTest_NativeStringComparatorWrapper.h"
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namespace rocksdb {
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class NativeComparatorWrapperTestStringComparator
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: public Comparator {
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const char* Name() const {
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return "NativeComparatorWrapperTestStringComparator";
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}
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int Compare(
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const Slice& a, const Slice& b) const {
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return a.ToString().compare(b.ToString());
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}
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void FindShortestSeparator(
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std::string* start, const Slice& limit) const {
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return;
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}
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void FindShortSuccessor(
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std::string* key) const {
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return;
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}
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};
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} // end of rocksdb namespace
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/*
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* Class: org_rocksdb_NativeComparatorWrapperTest_NativeStringComparatorWrapper
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* Method: newStringComparator
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* Signature: ()J
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*/
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jlong Java_org_rocksdb_NativeComparatorWrapperTest_00024NativeStringComparatorWrapper_newStringComparator(
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JNIEnv* env , jobject jobj) {
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auto* comparator =
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new rocksdb::NativeComparatorWrapperTestStringComparator();
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return reinterpret_cast<jlong>(comparator);
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}
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