content: /*
   * 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.adapter.orc;
  
  import java.io.IOException;
  import org.apache.arrow.memory.BufferAllocator;
  import org.apache.arrow.vector.ipc.ArrowReader;
  
  /**
   * Orc Reader that allow accessing orc stripes in Orc file. This orc reader basically acts like an
   * ArrowReader iterator that iterate over orc stripes. Each stripe will be accessed via an
   * ArrowReader.
   */
  public class OrcReader implements AutoCloseable {
    private final OrcReaderJniWrapper jniWrapper;
    private BufferAllocator allocator;
  
    /** reference to native reader instance. */
    private final long nativeInstanceId;
  
    /**
     * Create an OrcReader that iterate over orc stripes.
     *
     * @param filePath file path to target file, currently only support local file.
     * @param allocator allocator provided to ArrowReader.
     * @throws IOException throws exception in case of file not found
     */
    public OrcReader(String filePath, BufferAllocator allocator)
        throws IOException, IllegalAccessException {
      this.allocator = allocator;
      this.jniWrapper = OrcReaderJniWrapper.getInstance();
      this.nativeInstanceId = jniWrapper.open(filePath);
    }
  
    /**
     * Seek to designated row. Invoke NextStripeReader() after seek will return stripe reader starting
     * from designated row.
     *
     * @param rowNumber the rows number to seek
     * @return true if seek operation is succeeded
     */
    public boolean seek(int rowNumber) throws IllegalArgumentException {
      return jniWrapper.seek(nativeInstanceId, rowNumber);
    }
  
    /**
     * Get a stripe level ArrowReader with specified batchSize in each record batch.
     *
     * @param batchSize the number of rows loaded on each iteration
     * @return ArrowReader that iterate over current stripes
     */
    public ArrowReader nextStripeReader(long batchSize) throws IllegalArgumentException {
      long stripeReaderId = jniWrapper.nextStripeReader(nativeInstanceId, batchSize);
      if (stripeReaderId < 0) {
        return null;
      }
  
      return new OrcStripeReader(stripeReaderId, allocator);
    }
  
    /**
     * The number of stripes in the file.
     *
     * @return number of stripes
     */
    public int getNumberOfStripes() throws IllegalArgumentException {
      return jniWrapper.getNumberOfStripes(nativeInstanceId);
    }
  
    @Override
    public void close() {
      jniWrapper.close(nativeInstanceId);
    }
  }
  