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.sdk.util.construction;
  
  import java.util.List;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.util.construction.CoderTranslation.TranslationContext;
  
  /**
   * An interface that translates coders to components and back.
   *
   * <p>This interface is incomplete. Coders must in the general case have the capability to encode an
   * additional payload, which is not currently supported. This exists as a temporary measure.
   */
  public interface CoderTranslator<T extends Coder<?>> {
    /** Extract all component {@link Coder coders} within a coder. */
    List<? extends Coder<?>> getComponents(T from);
  
    /**
     * Returns the serialized payload that will be provided when deserializing this coder, if any. If
     * there is no payload, a byte array of length 0 should be returned.
     *
     * <p>The default implementation returns a byte array of length zero.
     */
    default byte[] getPayload(T from) {
      return new byte[0];
    }
  
    /**
     * Create a {@link Coder} from its component {@link Coder coders} using the specified translation
     * context.
     */
    T fromComponents(List<Coder<?>> components, byte[] payload, TranslationContext context);
  }
  