org.objectweb.medor.tuple.api
Interface TupleCollection
- BinaryEvaluatedTC, CachedTupleCollection
- BasicBinaryEvalutedTC, BinaryImplicitTC, CartesianEvaluatedTC, EmptyTupleCollection, ExplicitTupleCollection, JDBCTupleCollection, NestEvaluatedTC, ProjectEvaluatedTC, SelProjEvaluatedTC, UnnestEvaluatedTC, WindowCachedTupleCollection
public interface TupleCollection
This interface represent collections of tuples wich are manipulated by MEDOR.
A TupleCollection is a set of data typically representing the result of
querying a data source result.
Like JDBC ResultSets, a TupleCollection is scrollable over
iteration methods. The number, types and properties of a TupleCollection
object's
attribute are provided by the TupleStructure object returned by the
TupleCollection.getMetaData() method.
For example, to print all values of the first attribute of a
TupleCollection tc :
while (!tci.isLast()){
System.out.println(tci.getJavaObject(1));
tci.next();
}
Methods are provided to enumerate through the attributes of the TupleCollection
This Interface represent also the data flow in the Query Tree wich also represents
the result of a query.
void | close() - It closes the TupleCollection, relaeases used resources
(example : ResultSet).
|
void | first() - Moves the cursor to the first Tuple, row number 1.
|
TupleStructure | getMetaData() - Retrieves the number,types and stors properties of the data sources of this TupleCollection Object.
|
int | getRow() - Retrieves the current row Number.
|
Tuple | getTuple() - Returns the Tuple value of the current row of this TupleCollection object.
|
Tuple | getTuple(int row) - Returns the Tuple value of the designeted row of this TupleCollection object.
|
boolean | isEmpty() - Tell whether the current TupleCollection Object is empty or no.
|
boolean | isLast() - Indicates whether the cursor is on the last row of this TupleCollection object.
|
boolean | next() - Moves the cursor down one row from its current position to the next tuple of this
TupleCollection object.
|
boolean | row(int row) - Moves the cursor to the given row number in this TupleCollection object.
|
close
public void close()
throws MedorException
It closes the TupleCollection, relaeases used resources
(example : ResultSet). The next uses of the TupleCollection will throw
an exception.
first
public void first()
throws MedorException
Moves the cursor to the first Tuple, row number 1.
MedorException
- if data source access error
getMetaData
public TupleStructure getMetaData()
throws MedorException
Retrieves the number,types and stors properties of the data sources of this TupleCollection Object.
- a TupleCollectionMetaData Object defining teh TupleCollection.
MedorException
- if a data source access error occurs
getRow
public int getRow()
throws MedorException
Retrieves the current row Number.
- -1 if the iterator is out of bounds of the TupleCollection or if it is empty.
MedorException
- if data source access error.
getTuple
public Tuple getTuple()
throws MedorException
Returns the Tuple value of the current row of this TupleCollection object.
- the value of the current Tuple.
MedorException
- if data source access error.
getTuple
public Tuple getTuple(int row)
throws MedorException
Returns the Tuple value of the designeted row of this TupleCollection object.
row
- :int
- the a Tuple Number row.
MedorException
- if data source access error.
isEmpty
public boolean isEmpty()
throws MedorException
Tell whether the current TupleCollection Object is empty or no.
- true if the TupleCollection is empty.
MedorException
- if data source access error.
isLast
public boolean isLast()
throws MedorException
Indicates whether the cursor is on the last row of this TupleCollection object.
- true if the current Tuple is the last one or if the TupleCollection is Empty.
MedorException
- if data source access error
next
public boolean next()
throws MedorException
Moves the cursor down one row from its current position to the next tuple of this
TupleCollection object.
- true if move is impossible and false if move is not performed.
MedorException
- if data source access error
row
public boolean row(int row)
throws MedorException
Moves the cursor to the given row number in this TupleCollection object.
The first row is row 1, the second is row 2, and so on.
- true if move is possible
MedorException
- if row number is invelid or data source access error