org.objectweb.medor.tuple.api
Interface TupleCollection

All Known Subinterfaces:

BinaryEvaluatedTC, CachedTupleCollection

All Known Implementing Classes:

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.

Method Summary

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.

Method Detail

getMetaData

public TupleStructure getMetaData()
                           throws MedorException

Retrieves the number,types and stors properties of the data sources of this TupleCollection Object.

Returns:

a TupleCollectionMetaData Object defining teh TupleCollection.

Throws:

MedorException - if a data source access error occurs

isLast

public boolean isLast()
               throws MedorException

Indicates whether the cursor is on the last row of this TupleCollection object.

Returns:

true if the current Tuple is the last one or if the TupleCollection is Empty.

Throws:

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.

Returns:

true if move is impossible and false if move is not performed.

Throws:

MedorException - if data source access error

first

public void first()
           throws MedorException

Moves the cursor to the first Tuple, row number 1.

Throws:

MedorException - if data source access error

getRow

public int getRow()
           throws MedorException

Retrieves the current row Number.

Returns:

-1 if the iterator is out of bounds of the TupleCollection or if it is empty.

Throws:

MedorException - if data source access error.

getTuple

public Tuple getTuple()
               throws MedorException

Returns the Tuple value of the current row of this TupleCollection object.

Returns:

the value of the current Tuple.

Throws:

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.

Parameters:

row - :int

Returns:

the a Tuple Number row.

Throws:

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.

Returns:

true if move is possible

Throws:

MedorException - if row number is invelid or data source access error

isEmpty

public boolean isEmpty()
                throws MedorException

Tell whether the current TupleCollection Object is empty or no.

Returns:

true if the TupleCollection is empty.

Throws:

MedorException - if data source access error.

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.

Throws:

MedorException