public class RelationScan extends SourceOperator
tupleCounter
Constructor and Description |
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RelationScan(StorageManager sm,
Relation relation,
java.lang.String filename)
Constructs a new relation scan operator
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Modifier and Type | Method and Description |
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java.lang.String |
getFileName()
Fetch the filename that is to be scanned.
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protected java.util.List<Tuple> |
innerGetNext()
Inner method to retrieve the next tuple(s).
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protected java.util.List<Tuple> |
innerProcessTuple(Tuple tuple,
int inOp)
Inner processing of a tuple (never called, but made idempotent
for safety because I'm kinda stupid.)
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static void |
main(java.lang.String[] args)
Debug main
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protected Relation |
setOutputRelation()
Sets the output relation of this relation scan.
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protected void |
setup()
Sets up the relation scan.
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protected java.lang.String |
toStringSingle()
Textual representation.
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allDone, cleanup, getInputOperator, getMultiNext, getNext, getNumberOfInputs, getOutputRelation, prefix, processTuple, setInputs, toString, toString, tuples
public RelationScan(StorageManager sm, Relation relation, java.lang.String filename) throws EngineException
sm
- this scanner's storage manager.relation
- the relation this scanner scans.filename
- the filename of the file that stores the
relation.EngineException
- thrown whenever the relation scanner
cannot be properly initialised.public java.lang.String getFileName()
protected void setup() throws EngineException
setup
in class Operator
EngineException
- whenever the relation scan cannot be
set up.protected java.util.List<Tuple> innerGetNext() throws EngineException
innerGetNext
in class Operator
EngineException
- whenever the next tuple(s) cannot be
retrieved.protected java.util.List<Tuple> innerProcessTuple(Tuple tuple, int inOp) throws EngineException
innerProcessTuple
in class Operator
tuple
- the tuple to be processed.inOp
- the source of this tuple.EngineException
- never thrown by default (legacy call)protected Relation setOutputRelation() throws EngineException
setOutputRelation
in class Operator
EngineException
- thrown whenever the output relation
cannot be set.protected java.lang.String toStringSingle()
toStringSingle
in class Operator
public static void main(java.lang.String[] args)
args
- arguments