zhztheplayer commented on code in PR #14151: URL: https://github.com/apache/arrow/pull/14151#discussion_r972724760
########## java/dataset/src/main/java/org/apache/arrow/dataset/file/NativeScannerAdaptorImpl.java: ########## @@ -0,0 +1,146 @@ +/* + * 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. + */ + +package org.apache.arrow.dataset.file; + +import java.io.IOException; +import java.util.Iterator; + +import org.apache.arrow.c.ArrowArray; +import org.apache.arrow.c.Data; +import org.apache.arrow.dataset.jni.NativeRecordBatchIterator; +import org.apache.arrow.dataset.scanner.ScanTask; +import org.apache.arrow.dataset.scanner.Scanner; +import org.apache.arrow.memory.BufferAllocator; +import org.apache.arrow.memory.RootAllocator; +import org.apache.arrow.vector.ipc.ArrowReader; + +/** + * Default implementation of {@link NativeScannerAdaptor}. + */ +public class NativeScannerAdaptorImpl implements NativeScannerAdaptor, AutoCloseable { + + private final Scanner scanner; + private final BufferAllocator allocator; + + /** + * Constructor. + * + * @param scanner the delegated scanner. + */ + public NativeScannerAdaptorImpl(Scanner scanner, BufferAllocator allocator) { + this.scanner = scanner; + this.allocator = allocator; + } + + @Override + public NativeRecordBatchIterator scan() { + final Iterable<? extends ScanTask> tasks = scanner.scan(); + return new IteratorImpl(tasks, allocator); + } + + @Override + public void close() throws Exception { + scanner.close(); + } + + private static class IteratorImpl implements NativeRecordBatchIterator { + + private final Iterator<? extends ScanTask> taskIterator; + + private ScanTask currentTask = null; + private ArrowReader reader = null; + + private BufferAllocator allocator = null; + + public IteratorImpl(Iterable<? extends ScanTask> tasks, + BufferAllocator allocator) { + this.taskIterator = tasks.iterator(); + this.allocator = allocator; + } + + @Override + public void close() throws Exception { + closeCurrent(); + } + + private void closeCurrent() throws Exception { + if (currentTask == null) { + return; + } + currentTask.close(); + reader.close(); + } + + private boolean advance() { + if (!taskIterator.hasNext()) { + return false; + } + try { + closeCurrent(); + } catch (Exception e) { + throw new RuntimeException(e); + } + currentTask = taskIterator.next(); + reader = currentTask.execute(); + return true; + } + @Override + public boolean hasNext() { + + if (currentTask == null) { + if (!advance()) { + return false; + } + } + try { + if (!reader.loadNextBatch()) { + if (!advance()) { + return false; + } + } + return true; + } catch (IOException e) { + throw new RuntimeException(e); + } + } + + byte[] longtoBytes(long data) { + return new byte[]{ + (byte) ((data >> 0) & 0xff), + (byte) ((data >> 8) & 0xff), + (byte) ((data >> 16) & 0xff), + (byte) ((data >> 24) & 0xff), + (byte) ((data >> 32) & 0xff), + (byte) ((data >> 40) & 0xff), + (byte) ((data >> 48) & 0xff), + (byte) ((data >> 56) & 0xff), + }; + } Review Comment: Is it necessary to conduct this kind of encoding? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
