com.google.cloud.dataflow.sdk.transforms.windowing.PartitioningWindowFn 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.
/*
* 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.Arrays;
import java.util.Collection;
/**
* A {@link WindowFn} that places each value into exactly one window based on its timestamp and
* never merges windows.
*
* @param type of elements being windowed
* @param window type
*/
public abstract class PartitioningWindowFn
extends NonMergingWindowFn {
/**
* Returns the single window to which elements with this timestamp belong.
*/
public abstract W assignWindow(Instant timestamp);
@Override
public final Collection assignWindows(AssignContext c) {
return Arrays.asList(assignWindow(c.timestamp()));
}
@Override
public W getSideInputWindow(final BoundedWindow window) {
if (window instanceof GlobalWindow) {
throw new IllegalArgumentException(
"Attempted to get side input window for GlobalWindow from non-global WindowFn");
}
return assignWindow(window.maxTimestamp());
}
@Override
public boolean assignsToSingleWindow() {
return true;
}
@Override
public Instant getOutputTime(Instant inputTimestamp, W window) {
return inputTimestamp;
}
}