Module org.eclipse.persistence.core

Package org.eclipse.persistence.internal.sessions.remote

Class RemoteScrollableCursor

java.lang.Object

org.eclipse.persistence.queries.Cursor

org.eclipse.persistence.queries.ScrollableCursor

org.eclipse.persistence.internal.sessions.remote.RemoteScrollableCursor

All Implemented Interfaces:

Serializable, Enumeration, Iterator, ListIterator

public class RemoteScrollableCursor
extends ScrollableCursor

Purpose: The object is used as a wrapper to the ScrollableCursor object in the remote transaction (via RMI, CORBA, etc.)

Responsibilities: Wraps a database result set cursor to provide a stream to the remote client side on the resulting selected objects.

Note: Most of the APIs only work with JDBC 2.0

Since:

TOPLink/Java 3.0

Author:

King (Yaoping) Wang

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected ObjID	id	This is a unique id for remote cursored stream
protected boolean	isClosed	Return if the stream is closed

Fields inherited from class org.eclipse.persistence.queries.ScrollableCursor

atEndOfCursor, nextObject, previousObject, previousRow

Fields inherited from class org.eclipse.persistence.queries.Cursor

executionSession, fields, initiallyConformingIndex, nextRow, objectCollection, policy, position, query, resultSet, selectionCriteriaClone, session, size, statement, translationRow

Constructor Summary

Constructors

Constructor	Description
RemoteScrollableCursor(ScrollableCursor serverScrollableCursor)

Method Summary

Modifier and Type	Method	Description
boolean	absolute(int rows)	Moves the cursor to the given row number in the result set
void	afterLast()	Moves the cursor to the end of the result set, just after the last row.
void	beforeFirst()	Moves the cursor to the front of the result set, just before the first row
void	close()	Close the wrapped cursored stream This should be performed whenever the user has finished with the stream.
int	currentIndex()	Retrieves the current row index number
boolean	first()	Moves the cursor to the first row in the result set
protected int	getCursorSize()	INTERNAL: Retreive the size of the wrapped cursored stream.
ObjID	getID()	INTERNAL: Retreive the OID of the wrapped cursored stream.
boolean	isAfterLast()	Indicates whether the cursor is after the last row in the result set.
boolean	isBeforeFirst()	Indicates whether the cursor is before the first row in the result set.
boolean	isClosed()	INTERNAL: Return if the stream is closed.
boolean	isFirst()	Indicates whether the cursor is on the first row of the result set.
boolean	isLast()	Indicates whether the cursor is on the last row of the result set.
boolean	last()	Moves the cursor to the last row in the result set
boolean	relative(int rows)	Moves the cursor a relative number of rows, either positive or negative.
protected Object	retrieveNextObject()	INTERNAL: This method differs slightly from conventional read() operation on a Java stream.
protected Object	retrievePreviousObject()	INTERNAL: CR#4139 Read the previous row from the result set.

Methods inherited from class org.eclipse.persistence.queries.ScrollableCursor

add, clearNextAndPrevious, clearNextAndPreviousObject, getKnownCursorSize, getNextObject, getPosition, getPreviousObject, hasMoreElements, hasNext, hasNextElement, hasPrevious, loadNext, loadPrevious, next, next, nextElement, nextIndex, previous, previousIndex, set, setNextObject, setPreviousObject

Methods inherited from class org.eclipse.persistence.queries.Cursor

buildAndRegisterObject, clear, finalize, getAccessor, getExecutionSession, getFields, getInitiallyConformingIndex, getObjectCollection, getPageSize, getPolicy, getQuery, getResultSet, getSelectionCriteriaClone, getSession, getStatement, getTranslationRow, remove, setExecutionSession, setFields, setInitiallyConformingIndex, setObjectCollection, setPolicy, setPosition, setResultSet, setSelectionCriteriaClone, setSession, setSize, setTranslationRow, size

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Enumeration

asIterator

Methods inherited from interface java.util.Iterator

forEachRemaining

Methods inherited from interface java.util.ListIterator

remove

Field Detail

id

protected ObjID id

This is a unique id for remote cursored stream

isClosed

protected boolean isClosed

Return if the stream is closed

Constructor Detail

RemoteScrollableCursor

public RemoteScrollableCursor(ScrollableCursor serverScrollableCursor)

Method Detail

absolute

public boolean absolute(int rows)
                 throws DatabaseException

Moves the cursor to the given row number in the result set

Overrides:

absolute in class ScrollableCursor

Throws:

DatabaseException

afterLast

public void afterLast()
               throws DatabaseException

Moves the cursor to the end of the result set, just after the last row.

Overrides:

afterLast in class ScrollableCursor

Throws:

DatabaseException

beforeFirst

public void beforeFirst()
                 throws DatabaseException

Moves the cursor to the front of the result set, just before the first row

Overrides:

beforeFirst in class ScrollableCursor

Throws:

DatabaseException

close

public void close()
           throws DatabaseException

Close the wrapped cursored stream This should be performed whenever the user has finished with the stream.

Overrides:

close in class Cursor

Throws:

DatabaseException

currentIndex

public int currentIndex()
                 throws DatabaseException

Retrieves the current row index number

Overrides:

currentIndex in class ScrollableCursor

Throws:

DatabaseException

first

public boolean first()
              throws DatabaseException

Moves the cursor to the first row in the result set

Overrides:

first in class ScrollableCursor

Throws:

DatabaseException

getCursorSize

protected int getCursorSize()

INTERNAL: Retreive the size of the wrapped cursored stream.

Overrides:

getCursorSize in class ScrollableCursor

getID

public ObjID getID()

INTERNAL: Retreive the OID of the wrapped cursored stream.

isAfterLast

public boolean isAfterLast()
                    throws DatabaseException

Indicates whether the cursor is after the last row in the result set.

Overrides:

isAfterLast in class ScrollableCursor

Throws:

DatabaseException

isBeforeFirst

public boolean isBeforeFirst()
                      throws DatabaseException

Indicates whether the cursor is before the first row in the result set.

Overrides:

isBeforeFirst in class ScrollableCursor

Throws:

DatabaseException

isClosed

public boolean isClosed()

INTERNAL: Return if the stream is closed.

Overrides:

isClosed in class Cursor

isFirst

public boolean isFirst()
                throws DatabaseException

Indicates whether the cursor is on the first row of the result set.

Overrides:

isFirst in class ScrollableCursor

Throws:

DatabaseException

isLast

public boolean isLast()
               throws DatabaseException

Indicates whether the cursor is on the last row of the result set.

Overrides:

isLast in class ScrollableCursor

Throws:

DatabaseException

last

public boolean last()
             throws DatabaseException

Moves the cursor to the last row in the result set

Overrides:

last in class ScrollableCursor

Throws:

DatabaseException

relative

public boolean relative(int rows)
                 throws DatabaseException

Moves the cursor a relative number of rows, either positive or negative. Attempting to move beyond the first/last row in the result set positions the cursor before/after the the first/last row

Overrides:

relative in class ScrollableCursor

Throws:

DatabaseException

retrieveNextObject

protected Object retrieveNextObject()
                             throws DatabaseException,
                                    QueryException

INTERNAL: This method differs slightly from conventional read() operation on a Java stream. This method return the next object in the collection rather than specifying the number of bytes to be read in. Return the next object from the collection, if beyond the read limit read from the cursor

Overrides:

retrieveNextObject in class ScrollableCursor

Returns:

next object in stream

Throws:

DatabaseException - if read pass end of stream

QueryException

retrievePreviousObject

protected Object retrievePreviousObject()
                                 throws DatabaseException

INTERNAL: CR#4139 Read the previous row from the result set. It is used solely for scrollable cursor support.

Overrides:

retrievePreviousObject in class ScrollableCursor

Throws:

DatabaseException