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 org.apache.beam.sdk.extensions.euphoria.core.annotation.audience.Audience;
  import org.apache.beam.sdk.extensions.euphoria.core.annotation.operator.Derived;
  import org.apache.beam.sdk.extensions.euphoria.core.annotation.operator.StateComplexity;
  import org.apache.beam.sdk.extensions.euphoria.core.client.functional.ExtractEventTime;
  import org.apache.beam.sdk.extensions.euphoria.core.client.io.Collector;
  import org.apache.beam.sdk.extensions.euphoria.core.client.operator.base.Builders;
  import org.apache.beam.sdk.extensions.euphoria.core.client.operator.base.Operator;
  import org.apache.beam.sdk.extensions.euphoria.core.client.util.PCollectionLists;
  import org.apache.beam.sdk.extensions.euphoria.core.translate.OperatorTransform;
  import org.apache.beam.sdk.transforms.DoFn;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.PCollectionList;
  import org.apache.beam.sdk.values.TypeDescriptor;
  import org.checkerframework.checker.nullness.qual.Nullable;
  import org.joda.time.Duration;
  
  /**
   * A convenient alias for assignment of event time.
   *
   * <p>Can be rewritten as:
   *
   * <pre>{@code
   * PCollection<T> input = ...;
   * PCollection<T> withStamps = FlatMap.of(input)
   *    .using(t -> t)
   *    .eventTimeBy(evt-time-fn)
   *    .output();
   * }</pre>
   *
   * @deprecated Use Java SDK directly, Euphoria is scheduled for removal in a future release.
   */
  @Audience(Audience.Type.CLIENT)
  @Derived(state = StateComplexity.ZERO, repartitions = 0)
  @SuppressWarnings({
    "rawtypes", // TODO(https://github.com/apache/beam/issues/20447)
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  @Deprecated
  public class AssignEventTime<InputT> extends Operator<InputT>
      implements CompositeOperator<InputT, InputT> {
  
    /**
     * Starts building a named {@link AssignEventTime} operator.
     *
     * @param name a user provided name of the new operator to build
     * @return a builder to complete the setup of the new {@link AssignEventTime} operator
     */
    public static OfBuilder named(@Nullable String name) {
      return new Builder(name);
    }
  
    /**
     * Starts building a nameless {@link AssignEventTime} operator to (re-)assign event time the given
     * input dataset's elements.
     *
     * @param <InputT> the type of elements of the input dataset
     * @param input the input data set to be processed
     * @return a builder to complete the setup of the new {@link AssignEventTime} operator
     * @see #named(String)
     * @see OfBuilder#of(PCollection)
     */
    public static <InputT> UsingBuilder<InputT> of(PCollection<InputT> input) {
      return named(null).of(input);
    }
  
    /** Builder for the 'of' step from the builder chain. */
    public interface OfBuilder extends Builders.Of {
  
      @Override
      <InputT> UsingBuilder<InputT> of(PCollection<InputT> input);
    }
  
    /** Builder for the 'using' step from the builder chain. */
    public interface UsingBuilder<InputT> {
  
      /**
       * @param fn the event time extraction function
       * @return the next builder to complete the setup
       * @see FlatMap.EventTimeBuilder#eventTimeBy(ExtractEventTime)
       */
      Builders.Output<InputT> using(ExtractEventTime<InputT> fn);
  
      /**
       * @param fn the event time extraction function
       * @param allowedTimestampSkew allowed timestamp skew when assigning timestamps back in time
       *     {@link DoFn#getAllowedTimestampSkew}.
       * @return the next builder to complete the setup
       * @see FlatMap.EventTimeBuilder#eventTimeBy(ExtractEventTime)
       */
      Builders.Output<InputT> using(ExtractEventTime<InputT> fn, Duration allowedTimestampSkew);
    }
  
    /** Last builder in a chain. It concludes this operators creation by calling {@link #output()}. */
    public static class Builder<InputT>
        implements OfBuilder, UsingBuilder<InputT>, Builders.Output<InputT> {
  
      private final @Nullable String name;
      private PCollection<InputT> input;
      private ExtractEventTime<InputT> eventTimeExtractor;
      private @Nullable Duration allowedTimestampSkew = null;
  
      private Builder(@Nullable String name) {
        this.name = name;
      }
  
      @Override
      public <T> UsingBuilder<T> of(PCollection<T> input) {
        @SuppressWarnings("unchecked")
        final Builder<T> cast = (Builder<T>) this;
        cast.input = input;
        return cast;
      }
  
      @Override
      public Builders.Output<InputT> using(ExtractEventTime<InputT> eventTimeExtractor) {
        this.eventTimeExtractor = eventTimeExtractor;
        return this;
      }
  
      @Override
      public Builders.Output<InputT> using(
          ExtractEventTime<InputT> eventTimeExtractor, Duration allowedTimestampSkew) {
        this.allowedTimestampSkew = allowedTimestampSkew;
        return using(eventTimeExtractor);
      }
  
      @Override
      public PCollection<InputT> output() {
        return OperatorTransform.apply(
            new AssignEventTime<>(
                name, eventTimeExtractor, allowedTimestampSkew, input.getTypeDescriptor()),
            PCollectionList.of(input));
      }
    }
  
    private final ExtractEventTime<InputT> eventTimeExtractor;
    private final @Nullable Duration allowedTimestampSkew;
  
    private AssignEventTime(
        @Nullable String name,
        ExtractEventTime<InputT> eventTimeExtractor,
        @Nullable Duration allowedTimestampSkew,
        @Nullable TypeDescriptor<InputT> outputType) {
      super(name, outputType);
      this.eventTimeExtractor = eventTimeExtractor;
      this.allowedTimestampSkew = allowedTimestampSkew;
    }
  
    /**
     * @return the user defined event time assigner
     * @see FlatMap#getEventTimeExtractor()
     */
    public ExtractEventTime<InputT> getEventTimeExtractor() {
      return eventTimeExtractor;
    }
  
    @Override
    public PCollection<InputT> expand(PCollectionList<InputT> inputs) {
      final PCollection<InputT> input = PCollectionLists.getOnlyElement(inputs);
      return FlatMap.named(getName().orElse(null))
          .of(input)
          .using(
              (InputT element, Collector<InputT> coll) -> coll.collect(element),
              input.getTypeDescriptor())
          .eventTimeBy(getEventTimeExtractor(), allowedTimestampSkew)
          .output();
    }
  }
  