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.kafka.common.internals;
  
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.Executor;
  import java.util.concurrent.TimeUnit;
  import java.util.function.Supplier;
  
  /**
   * This internal class exists because CompletableFuture exposes complete(), completeExceptionally() and
   * other methods which would allow erroneous completion by user code of a KafkaFuture returned from a
   * Kafka API to a client application.
   * @param <T> The type of the future value.
   */
  public class KafkaCompletableFuture<T> extends CompletableFuture<T> {
  
      /**
       * Completes this future normally. For internal use by the Kafka clients, not by user code.
       * @param value the result value
       * @return {@code true} if this invocation caused this CompletableFuture
       * to transition to a completed state, else {@code false}
       */
      boolean kafkaComplete(T value) {
          return super.complete(value);
      }
  
      /**
       * Completes this future exceptionally. For internal use by the Kafka clients, not by user code.
       * @param throwable the exception.
       * @return {@code true} if this invocation caused this CompletableFuture
       * to transition to a completed state, else {@code false}
       */
      boolean kafkaCompleteExceptionally(Throwable throwable) {
          return super.completeExceptionally(throwable);
      }
  
      @Override
      public boolean complete(T value) {
          throw erroneousCompletionException();
      }
  
      @Override
      public boolean completeExceptionally(Throwable ex) {
          throw erroneousCompletionException();
      }
  
      @Override
      public void obtrudeValue(T value) {
          throw erroneousCompletionException();
      }
  
      @Override
      public void obtrudeException(Throwable ex) {
          throw erroneousCompletionException();
      }
  
      @Override
      public <U> CompletableFuture<U> newIncompleteFuture() {
          return new KafkaCompletableFuture<>();
      }
  
      @Override
      public CompletableFuture<T> completeAsync(Supplier<? extends T> supplier, Executor executor) {
          throw erroneousCompletionException();
      }
  
      @Override
      public CompletableFuture<T> completeAsync(Supplier<? extends T> supplier) {
          throw erroneousCompletionException();
      }
  
      @Override
      public CompletableFuture<T> completeOnTimeout(T value, long timeout, TimeUnit unit) {
          throw erroneousCompletionException();
      }
  
      private UnsupportedOperationException erroneousCompletionException() {
          return new UnsupportedOperationException("User code should not complete futures returned from Kafka clients");
      }
  }
  