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 com.datastax.oss.driver.example.guava.internal;
  
  import com.datastax.oss.driver.api.core.session.Request;
  import com.datastax.oss.driver.api.core.type.reflect.GenericType;
  import com.datastax.oss.driver.internal.core.context.InternalDriverContext;
  import com.datastax.oss.driver.internal.core.session.DefaultSession;
  import com.datastax.oss.driver.internal.core.session.RequestProcessor;
  import com.google.common.util.concurrent.Futures;
  import com.google.common.util.concurrent.ListenableFuture;
  import com.google.common.util.concurrent.SettableFuture;
  import java.util.concurrent.CompletionStage;
  
  /**
   * Wraps a {@link RequestProcessor} that returns {@link CompletionStage}s and converts them to a
   * {@link ListenableFuture}s.
   *
   * @param <T> The type of request
   * @param <U> The type of responses enclosed in the future response.
   */
  public class GuavaRequestAsyncProcessor<T extends Request, U>
      implements RequestProcessor<T, ListenableFuture<U>> {
  
    private final RequestProcessor<T, CompletionStage<U>> subProcessor;
  
    private final GenericType resultType;
  
    private final Class<?> requestClass;
  
    GuavaRequestAsyncProcessor(
        RequestProcessor<T, CompletionStage<U>> subProcessor,
        Class<?> requestClass,
        GenericType resultType) {
      this.subProcessor = subProcessor;
      this.requestClass = requestClass;
      this.resultType = resultType;
    }
  
    @Override
    public boolean canProcess(Request request, GenericType resultType) {
      return requestClass.isInstance(request) && resultType.equals(this.resultType);
    }
  
    @Override
    public ListenableFuture<U> process(
        T request, DefaultSession session, InternalDriverContext context, String sessionLogPrefix) {
      SettableFuture<U> future = SettableFuture.create();
      subProcessor
          .process(request, session, context, sessionLogPrefix)
          .whenComplete(
              (r, ex) -> {
                if (ex != null) {
                  future.setException(ex);
                } else {
                  future.set(r);
                }
              });
      return future;
    }
  
    @Override
    public ListenableFuture<U> newFailure(RuntimeException error) {
      return Futures.immediateFailedFuture(error);
    }
  }
  