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.runners.dataflow.worker.windmill.state;
  
  import java.io.IOException;
  import java.util.concurrent.Future;
  import org.apache.beam.runners.dataflow.worker.windmill.Windmill;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.util.concurrent.Futures;
  
  /**
   * Base class for implementations of {@link WindmillState} where the {@link #persist} call does not
   * require any asynchronous reading.
   */
  abstract class SimpleWindmillState extends WindmillState {
    @Override
    public final Future<Windmill.WorkItemCommitRequest> persist(
        WindmillStateCache.ForKeyAndFamily cache) throws IOException {
      return Futures.immediateFuture(persistDirectly(cache));
    }
  
    /**
     * Returns a {@link Windmill.WorkItemCommitRequest} that can be used to persist this state to
     * Windmill.
     */
    protected abstract Windmill.WorkItemCommitRequest persistDirectly(
        WindmillStateCache.ForKeyAndFamily cache) throws IOException;
  }
  