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.beam.examples.complete.datatokenization.utils;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.util.Arrays;
  import java.util.List;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.coders.CoderException;
  import org.apache.beam.sdk.coders.CustomCoder;
  import org.apache.beam.sdk.coders.NullableCoder;
  import org.apache.beam.sdk.coders.StringUtf8Coder;
  import org.apache.beam.sdk.values.TypeDescriptor;
  import org.apache.beam.sdk.values.TypeParameter;
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * The {@link FailsafeElementCoder} encodes and decodes {@link FailsafeElement} objects.
   *
   * <p>This coder is necessary until Avro supports parameterized types (<a
   * href="https://issues.apache.org/jira/browse/AVRO-1571">AVRO-1571</a>) without requiring to
   * explicitly specifying the schema for the type.
   *
   * @param <OriginalT> The type of the original payload to be encoded.
   * @param <CurrentT> The type of the current payload to be encoded.
   */
  public class FailsafeElementCoder<OriginalT, CurrentT>
      extends CustomCoder<FailsafeElement<OriginalT, CurrentT>> {
  
    private static final NullableCoder<String> STRING_CODER = NullableCoder.of(StringUtf8Coder.of());
    private final Coder<OriginalT> originalPayloadCoder;
    private final Coder<CurrentT> currentPayloadCoder;
  
    private FailsafeElementCoder(
        Coder<OriginalT> originalPayloadCoder, Coder<CurrentT> currentPayloadCoder) {
      this.originalPayloadCoder = originalPayloadCoder;
      this.currentPayloadCoder = currentPayloadCoder;
    }
  
    public Coder<OriginalT> getOriginalPayloadCoder() {
      return originalPayloadCoder;
    }
  
    public Coder<CurrentT> getCurrentPayloadCoder() {
      return currentPayloadCoder;
    }
  
    public static <OriginalT, CurrentT> FailsafeElementCoder<OriginalT, CurrentT> of(
        Coder<OriginalT> originalPayloadCoder, Coder<CurrentT> currentPayloadCoder) {
      return new FailsafeElementCoder<>(originalPayloadCoder, currentPayloadCoder);
    }
  
    @Override
    public void encode(FailsafeElement<OriginalT, CurrentT> value, OutputStream outStream)
        throws IOException {
      if (value == null) {
        throw new CoderException("The FailsafeElementCoder cannot encode a null object!");
      }
  
      originalPayloadCoder.encode(value.getOriginalPayload(), outStream);
      currentPayloadCoder.encode(value.getPayload(), outStream);
      STRING_CODER.encode(value.getErrorMessage(), outStream);
      STRING_CODER.encode(value.getStacktrace(), outStream);
    }
  
    @Override
    public FailsafeElement<OriginalT, CurrentT> decode(InputStream inStream) throws IOException {
  
      OriginalT originalPayload = originalPayloadCoder.decode(inStream);
      CurrentT currentPayload = currentPayloadCoder.decode(inStream);
      @Nullable String errorMessage = STRING_CODER.decode(inStream);
      @Nullable String stacktrace = STRING_CODER.decode(inStream);
  
      return FailsafeElement.of(originalPayload, currentPayload)
          .setErrorMessage(errorMessage)
          .setStacktrace(stacktrace);
    }
  
    @Override
    public List<? extends Coder<?>> getCoderArguments() {
      return Arrays.asList(originalPayloadCoder, currentPayloadCoder);
    }
  
    @Override
    public TypeDescriptor<FailsafeElement<OriginalT, CurrentT>> getEncodedTypeDescriptor() {
      return new TypeDescriptor<FailsafeElement<OriginalT, CurrentT>>() {}.where(
              new TypeParameter<OriginalT>() {}, originalPayloadCoder.getEncodedTypeDescriptor())
          .where(new TypeParameter<CurrentT>() {}, currentPayloadCoder.getEncodedTypeDescriptor());
    }
  }
  