public class Select extends UnaryOperator
tupleCounter
Constructor and Description |
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Select(Operator operator,
Predicate predicate)
Constructs a new selection operator given its input.
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Modifier and Type | Method and Description |
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protected java.util.List<Tuple> |
innerProcessTuple(Tuple tuple,
int inOp)
Processes an incoming tuple.
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protected Relation |
setOutputRelation()
Return a new relation for this operator's output relation.
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protected java.lang.String |
toStringSingle()
Textual representation.
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getInputOperator
allDone, cleanup, getInputOperator, getMultiNext, getNext, getNumberOfInputs, getOutputRelation, innerGetNext, prefix, processTuple, setInputs, setup, toString, toString, tuples
public Select(Operator operator, Predicate predicate) throws EngineException
operator
- the input operator.predicate
- the predicate this selection operator
evaluates.EngineException
- thrown whenever the selection operator cannot
be properly constructed.protected java.util.List<Tuple> innerProcessTuple(Tuple tuple, int inOp) throws EngineException
innerProcessTuple
in class Operator
tuple
- the tuple to be processed.inOp
- the incoming operator this tuple belongs to (should
always default to '0').EngineException
- thrown whenever the tuple cannot be
evaluatedprotected Relation setOutputRelation() throws EngineException
setOutputRelation
in class Operator
EngineException
- whenever an output relation cannot be
constructed.protected java.lang.String toStringSingle()
toStringSingle
in class Operator