runners/google-cloud-dataflow-java/worker/src/main/java/org/apache/beam/runners/dataflow/worker/GroupAlsoByWindowFn.java

/*
 * 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.dataflow.worker;

import org.apache.beam.runners.core.GroupByKeyViaGroupByKeyOnly.GroupAlsoByWindow;
import org.apache.beam.runners.core.OutputWindowedValue;
import org.apache.beam.runners.core.SideInputReader;
import org.apache.beam.runners.core.StepContext;
import org.apache.beam.runners.core.TimerInternals;
import org.apache.beam.sdk.options.PipelineOptions;

/**
 * An interface for functions that execute {@link GroupAlsoByWindow}-like machinery and need access
 * to worker internals, such as {@link TimerInternals} and {@link OutputWindowedValue}.
 */
public abstract class GroupAlsoByWindowFn<InputT, OutputT> {
  /** Processes one input element. */
  public abstract void processElement(
      InputT element,
      PipelineOptions options,
      StepContext stepContext,
      SideInputReader sideInputReader,
      OutputWindowedValue<OutputT> output)
      throws Exception;
}