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.flink.translation.wrappers.streaming.stableinput;
  
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkNotNull;
  
  import java.util.stream.Stream;
  import java.util.stream.StreamSupport;
  import org.apache.flink.api.common.state.ListState;
  
  /** A non-keyed implementation of a {@link BufferingElementsHandler}. */
  public class NonKeyedBufferingElementsHandler<T> implements BufferingElementsHandler {
  
    static <T> NonKeyedBufferingElementsHandler<T> create(ListState<BufferedElement> elementState) {
      return new NonKeyedBufferingElementsHandler<>(elementState);
    }
  
    private final ListState<BufferedElement> elementState;
  
    private NonKeyedBufferingElementsHandler(ListState<BufferedElement> elementState) {
      this.elementState = checkNotNull(elementState);
    }
  
    @Override
    public Stream<BufferedElement> getElements() {
      try {
        return StreamSupport.stream(elementState.get().spliterator(), false);
      } catch (Exception e) {
        throw new RuntimeException("Failed to retrieve buffered element from state backend.", e);
      }
    }
  
    @Override
    public void buffer(BufferedElement element) {
      try {
        elementState.add(element);
      } catch (Exception e) {
        throw new RuntimeException("Failed to buffer element in state backend.", e);
      }
    }
  
    @Override
    public void clear() {
      elementState.clear();
    }
  }
  