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
   *
   *   https://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.avro.message;
  
  import org.apache.avro.util.ReusableByteArrayInputStream;
  import org.apache.avro.util.ReusableByteBufferInputStream;
  import org.apache.avro.util.internal.ThreadLocalWithInitial;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.nio.ByteBuffer;
  
  /**
   * Deserializes a single datum from a ByteBuffer, byte array, or InputStream.
   * 
   * @param <D> a datum class
   */
  public interface MessageDecoder<D> {
  
    /**
     * Deserialize a single datum from an InputStream.
     *
     * @param stream stream to read from
     * @return a datum read from the stream
     * @throws BadHeaderException     If the payload's header is not recognized.
     * @throws MissingSchemaException If the payload's schema cannot be found.
     * @throws IOException
     */
    D decode(InputStream stream) throws IOException;
  
    /**
     * Deserialize a single datum from an InputStream.
     *
     * @param stream stream to read from
     * @param reuse  a datum instance to reuse, avoiding instantiation if possible
     * @return a datum read from the stream
     * @throws BadHeaderException     If the payload's header is not recognized.
     * @throws MissingSchemaException If the payload's schema cannot be found.
     * @throws IOException
     */
    D decode(InputStream stream, D reuse) throws IOException;
  
    /**
     * Deserialize a single datum from a ByteBuffer.
     *
     * @param encoded a ByteBuffer containing an encoded datum
     * @return a datum read from the stream
     * @throws BadHeaderException     If the payload's header is not recognized.
     * @throws MissingSchemaException If the payload's schema cannot be found.
     * @throws IOException
     */
    D decode(ByteBuffer encoded) throws IOException;
  
    /**
     * Deserialize a single datum from a ByteBuffer.
     *
     * @param encoded a ByteBuffer containing an encoded datum
     * @param reuse   a datum instance to reuse, avoiding instantiation if possible
     * @return a datum read from the stream
     * @throws BadHeaderException     If the payload's header is not recognized.
     * @throws MissingSchemaException If the payload's schema cannot be found.
     * @throws IOException
     */
    D decode(ByteBuffer encoded, D reuse) throws IOException;
  
    /**
     * Deserialize a single datum from a byte array.
     *
     * @param encoded a byte array containing an encoded datum
     * @return a datum read from the stream
     * @throws BadHeaderException     If the payload's header is not recognized.
     * @throws MissingSchemaException If the payload's schema cannot be found.
     * @throws IOException
     */
    D decode(byte[] encoded) throws IOException;
  
    /**
     * Deserialize a single datum from a byte array.
     *
     * @param encoded a byte array containing an encoded datum
     * @param reuse   a datum instance to reuse, avoiding instantiation if possible
     * @return a datum read from the stream
     * @throws BadHeaderException     If the payload's header is not recognized.
     * @throws MissingSchemaException If the payload's schema cannot be found.
     * @throws IOException
     */
    D decode(byte[] encoded, D reuse) throws IOException;
  
    /**
     * Base class for {@link MessageEncoder} implementations that provides default
     * implementations for most of the {@code DatumEncoder} API.
     * <p>
     * Implementations provided by this base class are thread-safe.
     *
     * @param <D> a datum class
     */
    abstract class BaseDecoder<D> implements MessageDecoder<D> {
  
      private static final ThreadLocal<ReusableByteArrayInputStream> BYTE_ARRAY_IN = ThreadLocalWithInitial
          .of(ReusableByteArrayInputStream::new);
  
      private static final ThreadLocal<ReusableByteBufferInputStream> BYTE_BUFFER_IN = ThreadLocalWithInitial
          .of(ReusableByteBufferInputStream::new);
  
      @Override
      public D decode(InputStream stream) throws IOException {
        return decode(stream, null);
      }
  
      @Override
      public D decode(ByteBuffer encoded) throws IOException {
        return decode(encoded, null);
      }
  
      @Override
      public D decode(byte[] encoded) throws IOException {
        return decode(encoded, null);
      }
  
      @Override
      public D decode(ByteBuffer encoded, D reuse) throws IOException {
        ReusableByteBufferInputStream in = BYTE_BUFFER_IN.get();
        in.setByteBuffer(encoded);
        return decode(in, reuse);
      }
  
      @Override
      public D decode(byte[] encoded, D reuse) throws IOException {
        ReusableByteArrayInputStream in = BYTE_ARRAY_IN.get();
        in.setByteArray(encoded, 0, encoded.length);
        return decode(in, reuse);
      }
  
    }
  }
  