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.transforms.windowing;
  
  import java.util.Collections;
  import java.util.List;
  import java.util.Locale;
  import java.util.Objects;
  import org.apache.beam.sdk.transforms.windowing.Trigger.OnceTrigger;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList;
  import org.checkerframework.checker.nullness.qual.Nullable;
  import org.joda.time.Duration;
  import org.joda.time.Instant;
  import org.joda.time.format.PeriodFormat;
  import org.joda.time.format.PeriodFormatter;
  
  /**
   * A {@link Trigger} trigger that fires at a specified point in processing time, relative to when
   * input first arrives.
   */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class AfterProcessingTime extends OnceTrigger {
  
    private static final PeriodFormatter DURATION_FORMATTER = PeriodFormat.wordBased(Locale.ENGLISH);
  
    private final List<TimestampTransform> timestampTransforms;
  
    private AfterProcessingTime(List<TimestampTransform> timestampTransforms) {
      super(null);
      this.timestampTransforms = timestampTransforms;
    }
  
    /**
     * Creates a trigger that fires when the current processing time passes the processing time at
     * which this trigger saw the first element in a pane.
     */
    public static AfterProcessingTime pastFirstElementInPane() {
      return new AfterProcessingTime(Collections.emptyList());
    }
  
    /**
     * The transforms applied to the arrival time of an element to determine when this trigger allows
     * output.
     */
    public List<TimestampTransform> getTimestampTransforms() {
      return timestampTransforms;
    }
  
    /**
     * Adds some delay to the original target time.
     *
     * @param delay the delay to add
     * @return An updated time trigger that will wait the additional time before firing.
     */
    public AfterProcessingTime plusDelayOf(final Duration delay) {
      return new AfterProcessingTime(
          ImmutableList.<TimestampTransform>builder()
              .addAll(timestampTransforms)
              .add(TimestampTransform.delay(delay))
              .build());
    }
  
    /**
     * Aligns timestamps to the smallest multiple of {@code period} since the {@code offset} greater
     * than the timestamp.
     */
    public AfterProcessingTime alignedTo(final Duration period, final Instant offset) {
      return new AfterProcessingTime(
          ImmutableList.<TimestampTransform>builder()
              .addAll(timestampTransforms)
              .add(TimestampTransform.alignTo(period, offset))
              .build());
    }
  
    /**
     * Aligns the time to be the smallest multiple of {@code period} greater than the epoch boundary
     * (aka {@code new Instant(0)}).
     */
    public AfterProcessingTime alignedTo(final Duration period) {
      return alignedTo(period, new Instant(0));
    }
  
    @Override
    public boolean isCompatible(Trigger other) {
      return this.equals(other);
    }
  
    @Override
    public Instant getWatermarkThatGuaranteesFiring(BoundedWindow window) {
      return BoundedWindow.TIMESTAMP_MAX_VALUE;
    }
  
    @Override
    protected Trigger getContinuationTrigger(List<Trigger> continuationTriggers) {
      return AfterSynchronizedProcessingTime.ofFirstElement();
    }
  
    @Override
    public String toString() {
      StringBuilder builder = new StringBuilder("AfterProcessingTime.pastFirstElementInPane()");
      for (TimestampTransform transform : getTimestampTransforms()) {
        if (transform instanceof TimestampTransform.Delay) {
          TimestampTransform.Delay delay = (TimestampTransform.Delay) transform;
          builder
              .append(".plusDelayOf(")
              .append(DURATION_FORMATTER.print(delay.getDelay().toPeriod()))
              .append(")");
        } else if (transform instanceof TimestampTransform.AlignTo) {
          TimestampTransform.AlignTo alignTo = (TimestampTransform.AlignTo) transform;
          builder
              .append(".alignedTo(")
              .append(DURATION_FORMATTER.print(alignTo.getPeriod().toPeriod()))
              .append(", ")
              .append(alignTo.getOffset())
              .append(")");
        }
      }
  
      return builder.toString();
    }
  
    @Override
    public boolean equals(@Nullable Object obj) {
      if (this == obj) {
        return true;
      }
      if (!(obj instanceof AfterProcessingTime)) {
        return false;
      }
  
      AfterProcessingTime that = (AfterProcessingTime) obj;
      return getTimestampTransforms().equals(that.getTimestampTransforms());
    }
  
    @Override
    public int hashCode() {
      return Objects.hash(getTimestampTransforms());
    }
  }
  