cz.seznam.euphoria.spark.UnaryFunctorWrapper Maven / Gradle / Ivy

Go to download
/**
 * Copyright 2016 Seznam.cz, a.s.
 *
 * 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 cz.seznam.euphoria.spark;

import com.google.common.collect.Iterators;
import cz.seznam.euphoria.core.client.dataset.windowing.Window;
import cz.seznam.euphoria.core.client.dataset.windowing.WindowedElement;
import cz.seznam.euphoria.core.client.functional.UnaryFunctor;
import org.apache.spark.api.java.function.FlatMapFunction;

import java.util.Iterator;
import java.util.Objects;

class UnaryFunctorWrapper
        implements FlatMapFunction, WindowedElement> {

  private final FunctionContextMem context;
  private final UnaryFunctor functor;

  public UnaryFunctorWrapper(UnaryFunctor functor) {
    this.functor = Objects.requireNonNull(functor);
    this.context = new FunctionContextMem<>();
  }

  @Override
  public Iterator> call(WindowedElement elem) {
    final WID window = elem.getWindow();
    final long timestamp = elem.getTimestamp();

    // setup user context
    context.clear();
    context.setWindow(window);

    functor.apply(elem.getElement(), context);

    // wrap output in WindowedElement
    return Iterators.transform(context.getOutputIterator(),
            e -> new WindowedElement<>(window, timestamp, e));
  }
}