/*
* 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.sdk.Pipeline;
import org.apache.beam.sdk.PipelineResult.State;
import org.apache.beam.sdk.runners.AppliedPTransform;
import org.apache.beam.sdk.transforms.PTransform;
import org.joda.time.Duration;
/**
* An executor that schedules and executes {@link AppliedPTransform AppliedPTransforms} for both
* source and intermediate {@link PTransform PTransforms}.
*/
interface PipelineExecutor {
/**
* Starts this executor. The provided collection is the collection of root transforms to
* initially schedule.
*
* @param rootTransforms
*/
void start(Collection<AppliedPTransform<?, ?, ?>> rootTransforms);
/**
* Blocks until the job being executed enters a terminal state. A job is completed after all
* root {@link AppliedPTransform AppliedPTransforms} have completed, and all
* {@link CommittedBundle Bundles} have been consumed. Jobs may also terminate abnormally.
*
* <p>Waits for up to the provided duration, or forever if the provided duration is less than or
* equal to zero.
*
* @return The terminal state of the Pipeline.
* @throws Exception whenever an executor thread throws anything, transfers to the
* waiting thread and rethrows it
*/
State waitUntilFinish(Duration duration) throws Exception;
/**
* Gets the current state of the {@link Pipeline}.
*/
State getPipelineState();
/**
* Shuts down the executor.
*
* <p>The executor may continue to run for a short time after this method returns.
*/
void stop();
}