Package org.apache.tajo.engine.planner.physical

Source Code of org.apache.tajo.engine.planner.physical.EvalExprExec

/**
* 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.tajo.engine.planner.physical;

import org.apache.tajo.worker.TaskAttemptContext;
import org.apache.tajo.engine.eval.EvalContext;
import org.apache.tajo.engine.planner.Target;
import org.apache.tajo.engine.planner.logical.EvalExprNode;
import org.apache.tajo.storage.Tuple;
import org.apache.tajo.storage.VTuple;

import java.io.IOException;

public class EvalExprExec extends PhysicalExec {
  private final EvalExprNode plan;
  private final EvalContext[] evalContexts;

  public EvalExprExec(final TaskAttemptContext context, final EvalExprNode plan) {
    super(context, plan.getInSchema(), plan.getOutSchema());
    this.plan = plan;

    evalContexts = new EvalContext[plan.getExprs().length];
    for (int i = 0; i < plan.getExprs().length; i++) {
      evalContexts[i] = plan.getExprs()[i].getEvalTree().newContext();
    }
  }

  @Override
  public void init() throws IOException {
  }

  /* (non-Javadoc)
  * @see PhysicalExec#next()
  */
  @Override
  public Tuple next() throws IOException {   
    Target [] targets = plan.getExprs();
    Tuple t = new VTuple(targets.length);
    for (int i = 0; i < targets.length; i++) {
      targets[i].getEvalTree().eval(evalContexts[i], inSchema, null);
      t.put(i, targets[i].getEvalTree().terminate(evalContexts[i]));
    }
    return t;
  }

  @Override
  public void rescan() throws IOException {   
  }

  @Override
  public void close() throws IOException {
  }
}
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