/*
* 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.runners.flink.translation.functions;
import org.apache.beam.sdk.transforms.join.RawUnionValue;
import org.apache.beam.sdk.util.WindowedValue;
import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.util.Collector;
/**
* A {@link FlatMapFunction} function that filters out those elements that don't belong in this
* output. We need this to implement MultiOutput ParDo functions in combination with
* {@link FlinkDoFnFunction}.
*/
public class FlinkMultiOutputPruningFunction<T>
implements FlatMapFunction<WindowedValue<RawUnionValue>, WindowedValue<T>> {
private final int ourOutputTag;
public FlinkMultiOutputPruningFunction(int ourOutputTag) {
this.ourOutputTag = ourOutputTag;
}
@Override
@SuppressWarnings("unchecked")
public void flatMap(
WindowedValue<RawUnionValue> windowedValue,
Collector<WindowedValue<T>> collector) throws Exception {
int unionTag = windowedValue.getValue().getUnionTag();
if (unionTag == ourOutputTag) {
collector.collect(
(WindowedValue<T>) windowedValue.withValue(windowedValue.getValue().getValue()));
}
}
}