// Copyright 2019 Google LLC
//
// 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.corp.gtech.ads.datacatalyst.components.mldatawindowingpipeline.transform;

import com.google.corp.gtech.ads.datacatalyst.components.mldatawindowingpipeline.model.Session;
import org.apache.beam.sdk.transforms.DoFn;
import org.apache.beam.sdk.values.KV;

/**
 * Maps from a Session to pairs of (userId, Session), so that Sessions can be grouped by userId.
 */
public class MapUserIdToSession extends DoFn<Session, KV<String, Session>> {
  public MapUserIdToSession() {
  }

  @ProcessElement
  public void processElement(ProcessContext context) {
    Session session = context.element();
    context.output(KV.of(session.getUserId(), session));
  }
}