/*
* 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.core;
import org.apache.beam.sdk.state.TimeDomain;
import org.apache.beam.sdk.transforms.DoFn;
import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
import org.apache.beam.sdk.util.WindowedValue;
import org.joda.time.Instant;
/**
* Interface for runners of {@link DoFn}'s that support pushback when reading side inputs,
* i.e. return elements that could not be processed because they require reading a side input
* window that is not ready.
*/
public interface PushbackSideInputDoFnRunner<InputT, OutputT> {
/** Calls the underlying {@link DoFn.StartBundle} method. */
void startBundle();
/**
* Call the underlying {@link DoFn.ProcessElement} method for the provided element
* for each window the element is in that is ready.
*
* @param elem the element to process in all ready windows
* @return each element that could not be processed because it requires a side input window
* that is not ready.
*/
Iterable<WindowedValue<InputT>> processElementInReadyWindows(WindowedValue<InputT> elem);
/** Calls the underlying {@link DoFn.OnTimer} method. */
void onTimer(String timerId, BoundedWindow window, Instant timestamp,
TimeDomain timeDomain);
/** Calls the underlying {@link DoFn.FinishBundle} method. */
void finishBundle();
}