
com.google.cloud.dataflow.sdk.util.StreamingPCollectionViewWriterFn Maven / Gradle / Ivy
/*
* 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.util;
import com.google.cloud.dataflow.sdk.coders.Coder;
import com.google.cloud.dataflow.sdk.transforms.DoFn;
import com.google.cloud.dataflow.sdk.values.PCollectionView;
import java.util.ArrayList;
import java.util.List;
/**
* Utility DoFn for writing streaming PCollectionViews.
*
* @param element type
*/
public class StreamingPCollectionViewWriterFn
extends DoFn, T> implements DoFn.RequiresWindowAccess {
private static final long serialVersionUID = 0;
private final PCollectionView> view;
private final Coder dataCoder;
public static StreamingPCollectionViewWriterFn create(
PCollectionView> view, Coder dataCoder) {
return new StreamingPCollectionViewWriterFn(view, dataCoder);
}
private StreamingPCollectionViewWriterFn(PCollectionView> view, Coder dataCoder) {
this.view = view;
this.dataCoder = dataCoder;
}
@Override
public void processElement(ProcessContext c) throws Exception {
List> output = new ArrayList<>();
for (T elem : c.element()) {
output.add(WindowedValue.of(elem, c.timestamp(), c.window(), c.pane()));
}
c.windowingInternals().writePCollectionViewData(
view.getTagInternal(), output, dataCoder);
}
}
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