/*
 * 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.direct;

import java.util.Collection;
import org.apache.beam.runners.core.construction.graph.QueryablePipeline;

/**
 * The interface that enables querying of a graph of independently executable stages and the inputs
 * and outputs of those stages.
 *
 * <p>Similar to {@link QueryablePipeline}. This exists primarily for legacy reasons, as an adapter
 * interface between the 'native' and 'portable' execution models that the DirectRunner supports.
 */
public interface ExecutableGraph<ExecutableT, CollectionT> {
  Collection<ExecutableT> getRootTransforms();

  Collection<ExecutableT> getExecutables();

  ExecutableT getProducer(CollectionT collection);

  Collection<CollectionT> getProduced(ExecutableT producer);

  Collection<CollectionT> getPerElementInputs(ExecutableT transform);

  Collection<ExecutableT> getPerElementConsumers(CollectionT pCollection);
}
