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.vector.util;
  
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.nio.channels.Channels;
  import org.apache.arrow.memory.BufferAllocator;
  import org.apache.arrow.vector.ipc.ReadChannel;
  import org.apache.arrow.vector.ipc.WriteChannel;
  import org.apache.arrow.vector.ipc.message.MessageChannelReader;
  import org.apache.arrow.vector.ipc.message.MessageResult;
  import org.apache.arrow.vector.ipc.message.MessageSerializer;
  import org.apache.arrow.vector.types.pojo.Schema;
  
  /** Schema utility class including serialization and deserialization. */
  public class SchemaUtility {
    private SchemaUtility() {}
  
    /** Deserialize Arrow schema from byte array. */
    public static Schema deserialize(byte[] bytes, BufferAllocator allocator) throws IOException {
      try (MessageChannelReader schemaReader =
          new MessageChannelReader(
              new ReadChannel(new ByteArrayReadableSeekableByteChannel(bytes)), allocator)) {
  
        MessageResult result = schemaReader.readNext();
        if (result == null) {
          throw new IOException("Unexpected end of input. Missing schema.");
        }
        return MessageSerializer.deserializeSchema(result.getMessage());
      }
    }
  
    /** Serialize Arrow schema into byte array. */
    public static byte[] serialize(Schema schema) throws IOException {
      final ByteArrayOutputStream out = new ByteArrayOutputStream();
      MessageSerializer.serialize(new WriteChannel(Channels.newChannel(out)), schema);
      return out.toByteArray();
    }
  }
  