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.tools;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.nio.channels.Channels;
  import org.apache.arrow.compression.CommonsCompressionFactory;
  import org.apache.arrow.memory.BufferAllocator;
  import org.apache.arrow.memory.RootAllocator;
  import org.apache.arrow.vector.VectorSchemaRoot;
  import org.apache.arrow.vector.ipc.ArrowFileWriter;
  import org.apache.arrow.vector.ipc.ArrowStreamReader;
  
  /** Converts an Arrow stream to an Arrow file. */
  public class StreamToFile {
    /** Reads an Arrow stream from <code>in</code> and writes it to <code>out</code>. */
    public static void convert(InputStream in, OutputStream out) throws IOException {
      BufferAllocator allocator = new RootAllocator(Integer.MAX_VALUE);
      try (ArrowStreamReader reader =
          new ArrowStreamReader(in, allocator, CommonsCompressionFactory.INSTANCE)) {
        VectorSchemaRoot root = reader.getVectorSchemaRoot();
        // load the first batch before instantiating the writer so that we have any dictionaries.
        // Only writeBatches if we load the first one.
        boolean writeBatches = reader.loadNextBatch();
        try (ArrowFileWriter writer = new ArrowFileWriter(root, reader, Channels.newChannel(out))) {
          writer.start();
          while (writeBatches) {
            writer.writeBatch();
            if (!reader.loadNextBatch()) {
              break;
            }
          }
          writer.end();
        }
      }
    }
  
    /**
     * Main method. Defaults to reading from standard in and standard out. If there are two arguments
     * the first is interpreted as the input file path, the second is the output file path.
     */
    public static void main(String[] args) throws IOException {
      InputStream in = System.in;
      OutputStream out = System.out;
      if (args.length == 2) {
        in = new FileInputStream(new File(args[0]));
        out = new FileOutputStream(new File(args[1]));
      }
      convert(in, out);
    }
  }
  