runners/local-java/src/main/java/org/apache/beam/runners/local/ExecutionDriver.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.local;

/** Drives the execution of a {@code Pipeline} by scheduling work. */
public interface ExecutionDriver {
  DriverState drive();

  /** The state of the driver. If the state is terminal, the driver can no longer make progress. */
  enum DriverState {
    CONTINUE(false),
    FAILED(true),
    SHUTDOWN(true);

    private final boolean terminal;

    DriverState(boolean terminal) {
      this.terminal = terminal;
    }

    public boolean isTermainal() {
      return terminal;
    }
  }
}