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.core;
  
  import java.util.Map;
  import org.apache.beam.sdk.state.State;
  import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
  
  /**
   * Interface for accessing persistent state while windows are merging.
   *
   * <p>For internal use only.
   */
  public interface MergingStateAccessor<K, W extends BoundedWindow> extends StateAccessor<K> {
    /**
     * Analogous to {@link #access}, but returned as a map from each window which is about to be
     * merged to the corresponding state. Only includes windows which are known to have state.
     */
    <StateT extends State> Map<W, StateT> accessInEachMergingWindow(StateTag<StateT> address);
  }
  