net.rim.device.api.database
Class BufferedCursor
java.lang.Object
net.rim.device.api.database.BufferedCursor
- All Implemented Interfaces:
- Cursor
public class BufferedCursor
- extends Object
- implements Cursor
Caches all rows in memory for bidirectional or random access. Suitable for
small cursors.
The buffered cursor may throw an OutOfMemoryError
if
it is used with huge data queries.
- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
Method Summary |
|
void |
close()
Closes the cursor, releasing all of its resources and making it
completely invalid. |
|
boolean |
first()
Navigates to the first row. |
|
int |
getColumnIndex(String columnName)
Returns the zero-based index for a given column name. |
|
String |
getColumnName(int columnIndex)
Returns the column name at a given zero-based column index. |
|
int |
getPosition()
Returns the current cursor position. |
|
Row |
getRow()
Retrieves the current row with its values. |
|
boolean |
isEmpty()
Determines if the cursor contains rows. |
|
boolean |
last()
Moves the cursor to the last row. |
|
boolean |
next()
Moves the cursor to the next row. |
|
boolean |
position(int row)
Positions the cursor on the specified position. |
|
boolean |
prev()
Navigates to the previous row, if it exists. |
BufferedCursor
public BufferedCursor(Cursor cursor)
throws NullPointerException
- Creates buffered cursor based on given delegate.
- Throws:
NullPointerException
- If the cursor parameter is NULL.- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
first
public boolean first()
throws DatabaseException
- Navigates to the first row.
- Specified by:
first
in interface Cursor
- Returns:
true
if there is at least one row in the cursor, false
if the
cursor is empty.
- Throws:
DatabaseException
- If the first row cannot be retrieved from the database or if
the current position is after the first row in a forward-only
cursor.- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
getPosition
public int getPosition()
throws DatabaseException
- Description copied from interface:
Cursor
- Returns the current cursor position.
If the cursor was not navigated through Cursor.next()
, Cursor.last()
or
similar methods, then its current position is before the first row and is
marked as -1.
- Specified by:
getPosition
in interface Cursor
- Returns:
- Current cursor position, or -1 when the cursor contains no rows or was
never navigated.
- Throws:
DatabaseException
- See Also:
Cursor.getPosition()
- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
getRow
public Row getRow()
throws DatabaseException
- Description copied from interface:
Cursor
- Retrieves the current row with its values.
The cursor must be positioned on a row for this method to return a non-null
value. When the cursor is first opened, the cursor is positioned before the first row and
this method returns null
. Call Cursor.first()
or
Cursor.next()
to navigate to the first row and then call getRow()
to
get the data.
- Specified by:
getRow
in interface Cursor
- Returns:
- The current row, or
null
if the cursor contains no rows or is not
positioned on a row.
- Throws:
DatabaseException
- See Also:
Cursor.getRow()
- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
last
public boolean last()
throws DatabaseException
- Description copied from interface:
Cursor
- Moves the cursor to the last row.
If the cursor is empty, the method returns false
.
- Specified by:
last
in interface Cursor
- Returns:
true
if the move succeeded; otherwise false
.
- Throws:
DatabaseException
- If the last row cannot be retrieved from the database.- See Also:
Cursor.last()
- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
next
public boolean next()
throws DatabaseException
- Description copied from interface:
Cursor
- Moves the cursor to the next row.
Calling the next()
method the first time positions the cursor on the first
row, if it is available. If the cursor is positioned on the last
row then calling next()
moves the pointer after the last row, and row
data access methods will return invalid data.
- Specified by:
next
in interface Cursor
- Returns:
true
if the move succeeded; otherwise false
.
- Throws:
DatabaseException
- See Also:
Cursor.next()
- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
position
public boolean position(int row)
throws DatabaseException
- Positions the cursor on the specified position.
- Specified by:
position
in interface Cursor
- Parameters:
row
- Zero-based position to move to.
- Returns:
true
if the move succeeded; otherwise false
.
- Throws:
DatabaseException
- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
prev
public boolean prev()
throws DatabaseException
- Navigates to the previous row, if it exists.
- Specified by:
prev
in interface Cursor
- Returns:
true
if there is a previous row; otherwise false
.
- Throws:
DatabaseException
- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
close
public void close()
throws DatabaseException
- Description copied from interface:
Cursor
- Closes the cursor, releasing all of its resources and making it
completely invalid.
- Specified by:
close
in interface Cursor
- Throws:
DatabaseException
- See Also:
Cursor.close()
- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
isEmpty
public boolean isEmpty()
throws DatabaseException
- Description copied from interface:
Cursor
- Determines if the cursor contains rows.
Information about whether the cursor is empty or not is available
only after navigating to a row through any of the following methods:
Cursor.first()
, Cursor.next()
, Cursor.last()
. If the cursor was
never navigated then this method returns true
, meaning that
no rows were fetched.
- Specified by:
isEmpty
in interface Cursor
- Returns:
true
if the cursor contains at least one row, false
otherwise.
- Throws:
DatabaseException
- If the database communication is broken.- See Also:
Cursor.isEmpty()
- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
getColumnIndex
public int getColumnIndex(String columnName)
throws DatabaseException
- Description copied from interface:
Cursor
- Returns the zero-based index for a given column name.
Column metadata is available only after navigation to
the first row. Call Cursor.next()
or Cursor.first()
before calling
this method.
- Specified by:
getColumnIndex
in interface Cursor
- Parameters:
columnName
- The name of the target column.
- Returns:
- Returns the zero-based column index for the given column name,
or -1 if the column name does not exist.
- Throws:
DatabaseException
- If cursor is closed.- See Also:
Cursor.getColumnIndex(String)
- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
getColumnName
public String getColumnName(int columnIndex)
throws DatabaseException
- Description copied from interface:
Cursor
- Returns the column name at a given zero-based column index.
Column metadata is available only after navigation to
the first row. Call Cursor.next()
or Cursor.first()
before calling
this method.
- Specified by:
getColumnName
in interface Cursor
- Parameters:
columnIndex
- The zero-based index of the target column.
- Returns:
- The column name for the given column index; or
null
if the given column index is larger than the number of columns.
- Throws:
DatabaseException
- If cursor is closed.- See Also:
Cursor.getColumnName(int)
- Category:
- Signed: This element is only accessible by signed applications. If you intend to use this element, please visit http://www.blackberry.com/go/codesigning to obtain a set of code signing keys. Code signing is only required for applications running on BlackBerry smartphones; development on BlackBerry Smartphone Simulators can occur without code signing.
- Since:
- BlackBerry API 5.0.0
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