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.sdk.extensions.euphoria.core.client.operator;
  
  import static java.util.Objects.requireNonNull;
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkState;
  
  import java.util.Optional;
  import org.apache.beam.sdk.extensions.euphoria.core.client.operator.base.Builders;
  import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
  import org.apache.beam.sdk.transforms.windowing.TimestampCombiner;
  import org.apache.beam.sdk.transforms.windowing.Trigger;
  import org.apache.beam.sdk.transforms.windowing.Window;
  import org.apache.beam.sdk.transforms.windowing.WindowFn;
  import org.apache.beam.sdk.values.WindowingStrategy;
  import org.checkerframework.checker.nullness.qual.Nullable;
  import org.joda.time.Duration;
  
  /**
   * Holds state of {@link Window} builder.
   *
   * @param <T> type of windowed element
   */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  class WindowBuilder<T>
      implements Builders.WindowBy<WindowBuilder<T>>,
          Builders.TriggeredBy<WindowBuilder<T>>,
          Builders.AccumulationMode<WindowBuilder<T>>,
          Builders.WindowedOutput<WindowBuilder<T>> {
  
    private @Nullable Window<T> window;
  
    /**
     * Get underlying window.
     *
     * @return maybe window
     */
    Optional<Window<T>> getWindow() {
      return Optional.ofNullable(window);
    }
  
    /**
     * Set underlying window. This is useful for building composite operators, such as {@link
     * ReduceByKey}.
     *
     * @param window the window
     */
    void setWindow(Window<T> window) {
      checkState(this.window == null, "Window is already set.");
      this.window = window;
    }
  
    @Override
    public <W extends BoundedWindow> WindowBuilder<T> windowBy(WindowFn<Object, W> windowFn) {
      checkState(window == null, "Window is already set.");
      window = Window.into(windowFn);
      return this;
    }
  
    @Override
    public WindowBuilder<T> triggeredBy(Trigger trigger) {
      window = requireNonNull(window).triggering(trigger);
      return this;
    }
  
    @Override
    public WindowBuilder<T> accumulationMode(WindowingStrategy.AccumulationMode accumulationMode) {
      switch (requireNonNull(accumulationMode)) {
        case DISCARDING_FIRED_PANES:
          window = requireNonNull(window).discardingFiredPanes();
          break;
        case ACCUMULATING_FIRED_PANES:
          window = requireNonNull(window).accumulatingFiredPanes();
          break;
        default:
          throw new IllegalArgumentException("Unknown accumulation mode [" + accumulationMode + "]");
      }
      return this;
    }
  
    @Override
    public WindowBuilder<T> withAllowedLateness(Duration allowedLateness) {
      window = requireNonNull(window).withAllowedLateness(requireNonNull(allowedLateness));
      return this;
    }
  
    @Override
    public WindowBuilder<T> withAllowedLateness(
        Duration allowedLateness, Window.ClosingBehavior closingBehavior) {
      window =
          requireNonNull(window)
              .withAllowedLateness(requireNonNull(allowedLateness), requireNonNull(closingBehavior));
      return this;
    }
  
    @Override
    public WindowBuilder<T> withTimestampCombiner(TimestampCombiner timestampCombiner) {
      window = requireNonNull(window).withTimestampCombiner(requireNonNull(timestampCombiner));
      return this;
    }
  
    @Override
    public WindowBuilder<T> withOnTimeBehavior(Window.OnTimeBehavior behavior) {
      window = requireNonNull(window).withOnTimeBehavior(requireNonNull(behavior));
      return this;
    }
  }
  