exec/java-exec/src/main/java/org/apache/drill/exec/record/AbstractSingleRecordBatch.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.drill.exec.record;

import org.apache.drill.exec.exception.OutOfMemoryException;
import org.apache.drill.exec.ops.FragmentContext;
import org.apache.drill.exec.physical.base.PhysicalOperator;

/**
 * Implements an AbstractUnaryRecordBatch where the incoming record batch is
 * known at the time of creation
 *
 * @param <T> the plan definition of the operator
 */
public abstract class AbstractSingleRecordBatch<T extends PhysicalOperator> extends AbstractUnaryRecordBatch<T> {

  protected final RecordBatch incoming;

  public AbstractSingleRecordBatch(T popConfig, FragmentContext context,
      RecordBatch incoming) throws OutOfMemoryException {
    super(popConfig, context);
    this.incoming = incoming;
  }

  @Override
  protected RecordBatch getIncoming() {
    return incoming;
  }

  /**
   * Based on lastKnownOutcome and if there are more records to be output for
   * current record boundary detected by EMIT outcome, this method returns EMIT
   * or OK outcome.
   *
   * @param hasMoreRecordInBoundary
   * @return EMIT - If the lastknownOutcome was EMIT and output records
   *         corresponding to all the incoming records in current record
   *         boundary is already produced.
   *         OK - otherwise
   */
  protected IterOutcome getFinalOutcome(boolean hasMoreRecordInBoundary) {
    final IterOutcome lastOutcome = getLastKnownOutcome();
    final boolean isLastOutcomeEmit = (IterOutcome.EMIT == lastOutcome);
    if (isLastOutcomeEmit && !hasMoreRecordInBoundary) {
      setLastKnownOutcome(IterOutcome.OK);
      return IterOutcome.EMIT;
    }
    return IterOutcome.OK;
  }
}