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;
  
  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;
  
  /** {@link PushedBackElementsHandler} that stores elements in a Flink operator state list. */
  class NonKeyedPushedBackElementsHandler<T> implements PushedBackElementsHandler<T> {
  
    static <T> NonKeyedPushedBackElementsHandler<T> create(ListState<T> elementState) {
      return new NonKeyedPushedBackElementsHandler<>(elementState);
    }
  
    private final ListState<T> elementState;
  
    private NonKeyedPushedBackElementsHandler(ListState<T> elementState) {
      this.elementState = checkNotNull(elementState);
    }
  
    @Override
    public Stream<T> getElements() throws Exception {
      return StreamSupport.stream(elementState.get().spliterator(), false);
    }
  
    @Override
    public void clear() {
      elementState.clear();
    }
  
    @Override
    public void pushBack(T element) throws Exception {
      elementState.add(element);
    }
  
    @Override
    public void pushBackAll(Iterable<T> elements) throws Exception {
      for (T e : elements) {
        // TODO: use addAll() once Flink has addAll(Iterable<T>)
        elementState.add(e);
      }
    }
  }
  