com.google.cloud.dataflow.sdk.transforms.windowing.BoundedWindow Maven / Gradle / Ivy

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Google Cloud Dataflow Java SDK provides a simple, Java-based interface for processing virtually any size data using Google cloud resources. This artifact includes entire Dataflow Java SDK.

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/*
 * Copyright (C) 2015 Google Inc.
 *
 * Licensed 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 com.google.cloud.dataflow.sdk.transforms.windowing;

import org.joda.time.Instant;

import java.util.concurrent.TimeUnit;

/**
 * A {@code BoundedWindow} represents a finite grouping of elements, with an
 * upper bound (larger timestamps represent more recent data) on the timestamps
 * of elements that can be placed in the window. This finiteness means that for
 * every window, at some point in time, all data for that window will have
 * arrived and can be processed together.
 *
 * Windows must also implement {@link Object#equals} and
 * {@link Object#hashCode} such that windows that are logically equal will
 * be treated as equal by {@code equals()} and {@code hashCode()}.
 */
public abstract class BoundedWindow {
  // The min and max timestamps that won't overflow when they are converted to
  // usec.
  public static final Instant TIMESTAMP_MIN_VALUE =
      new Instant(TimeUnit.MICROSECONDS.toMillis(Long.MIN_VALUE));
  public static final Instant TIMESTAMP_MAX_VALUE =
      new Instant(TimeUnit.MICROSECONDS.toMillis(Long.MAX_VALUE));

  /**
   * Returns the inclusive upper bound of timestamps for values in this window.
   */
  public abstract Instant maxTimestamp();
}