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.cql.AsyncResultSet;
  import com.datastax.oss.driver.api.core.cql.SimpleStatement;
  import com.datastax.oss.driver.api.core.session.Request;
  import com.datastax.oss.driver.api.core.type.reflect.GenericType;
  import com.datastax.oss.driver.core.session.RequestProcessorIT;
  import com.datastax.oss.driver.internal.core.context.InternalDriverContext;
  import com.datastax.oss.driver.internal.core.cql.CqlRequestAsyncProcessor;
  import com.datastax.oss.driver.internal.core.session.DefaultSession;
  import com.datastax.oss.driver.internal.core.session.RequestProcessor;
  import com.datastax.oss.driver.internal.core.util.concurrent.CompletableFutures;
  
  /**
   * A request processor that takes a given {@link KeyRequest#getKey} and generates a query, delegates
   * it to {@link CqlRequestAsyncProcessor} to get the integer value of a row and return it as a
   * result.
   */
  public class KeyRequestProcessor implements RequestProcessor<KeyRequest, Integer> {
  
    public static final GenericType<Integer> INT_TYPE = GenericType.of(Integer.class);
  
    private final CqlRequestAsyncProcessor subProcessor;
  
    KeyRequestProcessor(CqlRequestAsyncProcessor subProcessor) {
      this.subProcessor = subProcessor;
    }
  
    @Override
    public boolean canProcess(Request request, GenericType<?> resultType) {
      return request instanceof KeyRequest && resultType.equals(INT_TYPE);
    }
  
    @Override
    public Integer process(
        KeyRequest request,
        DefaultSession session,
        InternalDriverContext context,
        String sessionLogPrefix) {
  
      // Create statement from key and delegate it to CqlRequestSyncProcessor
      SimpleStatement statement =
          SimpleStatement.newInstance(
              "select v1 from test where k = ? and v0 = ?", RequestProcessorIT.KEY, request.getKey());
      AsyncResultSet result =
          CompletableFutures.getUninterruptibly(
              subProcessor.process(statement, session, context, sessionLogPrefix));
      // If not exactly 1 rows were found, return Integer.MIN_VALUE, otherwise return the value.
      if (result.remaining() != 1) {
        return Integer.MIN_VALUE;
      } else {
        return result.currentPage().iterator().next().getInt("v1");
      }
    }
  
    @Override
    public Integer newFailure(RuntimeException error) {
      throw error;
    }
  }
  