Github user ppadma commented on a diff in the pull request: https://github.com/apache/drill/pull/1121#discussion_r168317696 --- Diff: exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/protocol/OperatorDriver.java --- @@ -0,0 +1,183 @@ +/* + * 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.drill.exec.physical.impl.protocol; + +import org.apache.drill.common.exceptions.UserException; +import org.apache.drill.exec.ops.OperatorContext; +import org.apache.drill.exec.record.RecordBatch.IterOutcome; + +/** + * State machine that drives the operator executable. Converts + * between the iterator protocol and the operator executable protocol. + * Implemented as a separate class in anticipation of eventually + * changing the record batch (iterator) protocol. + */ + +public class OperatorDriver { + public enum State { START, SCHEMA, RUN, END, FAILED, CLOSED } + + private OperatorDriver.State state = State.START; + + /** + * Operator context. The driver "owns" the context and is responsible + * for closing it. + */ + + private final OperatorContext opContext; + private final OperatorExec operatorExec; + private final BatchAccessor batchAccessor; + private int schemaVersion; + + public OperatorDriver(OperatorContext opServicees, OperatorExec opExec) { --- End diff -- typo ? opServices instead of opServicees ?
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