[GitHub] [arrow] zhztheplayer commented on a change in pull request #7030: ARROW-7808: [Java][Dataset] Implement Datasets Java API by JNI to C++

[GitBox <gi...@apache.org>]

zhztheplayer commented on a change in pull request #7030:
URL: https://github.com/apache/arrow/pull/7030#discussion_r415483479



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File path: cpp/src/jni/dataset/jni_wrapper.cpp
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@@ -0,0 +1,577 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include <arrow/dataset/file_base.h>
+#include <arrow/dataset/api.h>
+#include <arrow/filesystem/localfs.h>
+#include <arrow/ipc/api.h>
+#include <arrow/util/iterator.h>
+#include <arrow/filesystem/hdfs.h>
+#include <arrow/io/api.h>
+#include <google/protobuf/io/coded_stream.h>
+#include <google/protobuf/message.h>
+#include "concurrent_map.h"
+#include "arrow/compute/kernel.h"
+#include "arrow/compute/kernels/cast.h"
+#include "arrow/compute/kernels/compare.h"
+#include "jni/dataset/Types.pb.h"
+
+#include "org_apache_arrow_dataset_jni_JniWrapper.h"
+#include "org_apache_arrow_dataset_file_JniWrapper.h"
+
+static jclass illegal_access_exception_class;
+static jclass illegal_argument_exception_class;
+static jclass runtime_exception_class;
+
+static jclass record_batch_handle_class;
+static jclass record_batch_handle_field_class;
+static jclass record_batch_handle_buffer_class;
+
+static jmethodID record_batch_handle_constructor;
+static jmethodID record_batch_handle_field_constructor;
+static jmethodID record_batch_handle_buffer_constructor;
+
+static jint JNI_VERSION = JNI_VERSION_1_6;
+
+using arrow::jni::ConcurrentMap;
+
+static ConcurrentMap<std::shared_ptr<arrow::dataset::DatasetFactory>> dataset_factory_holder_;

Review comment:
       Will do. But I kindly like the current pattern - it benefits more or less when debugging/tracing (self-growing id, instance cache, etc.), right? Is there any other consideration making it bad?




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