algebricks/algebricks-runtime/src/main/java/edu/uci/ics/hyracks/algebricks/runtime/evaluators/TupleFieldEvaluatorFactory.java

package edu.uci.ics.hyracks.algebricks.runtime.evaluators;

import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
import edu.uci.ics.hyracks.algebricks.runtime.base.IScalarEvaluator;
import edu.uci.ics.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
import edu.uci.ics.hyracks.data.std.api.IPointable;
import edu.uci.ics.hyracks.dataflow.common.data.accessors.IFrameTupleReference;

public class TupleFieldEvaluatorFactory implements IScalarEvaluatorFactory {
    private static final long serialVersionUID = 1L;

    private final int fieldIndex;

    public TupleFieldEvaluatorFactory(int fieldIndex) {
        this.fieldIndex = fieldIndex;
    }

    @Override
    public IScalarEvaluator createScalarEvaluator(IHyracksTaskContext ctx) throws AlgebricksException {
        return new IScalarEvaluator() {
            @Override
            public void evaluate(IFrameTupleReference tuple, IPointable result) throws AlgebricksException {
                result.set(tuple.getFieldData(fieldIndex), tuple.getFieldStart(fieldIndex),
                        tuple.getFieldLength(fieldIndex));
            }
        };
    }
}