org.brains2b.data.cursor
Class Cursor

java.lang.Object
  |
  +--org.brains2b.data.cursor.Cursor

Direct Known Subclasses:

OracleCursor

public class Cursor

extends java.lang.Object

Cursor is the Control class for a valid SQL select statement to be be used as a data class for which we can manipulate the data.

This includes inserting, deleting or selecting data, a bit like an Oracle Cursor.

Usage: Create a new Cursor object with a valid SQL connection and a String containing a valid SQL statement. Cursor c=new Cursor({Valid Connection},"A distinquising name", "SELECT NAME, DEPARTMENT FROM EMP,DEP WHERE NAME.DEP_ID=DEPARTMENT.ID"); After this a Select statement will return a CursorData object. See the javadoc for this object for more information. To get a new CursorData object use c.getNewCursorData()

Limitation: Updating and inserting will only proceed if the underlying database allows this particular operation for the particular query. Usually this only happens when all reference are explicit, all primary keys are set and all non-null values are filled. Cursor will pass the Exception thrown by the database through when there is a problem with mutating data.

Version:

0.2.1 [06-01-2004]

Author:

dennis@brains2b.nl

See Also:

CursorData

Field Summary

protected java.sql.Connection	m_con
protected java.lang.String	m_condition
protected java.lang.String	m_from
protected java.lang.String	m_groupBy
protected java.sql.PreparedStatement	m_prep
protected java.lang.String	m_select

Constructor Summary

Cursor()
Deprecated. not used, use Cursor(Connection,String,String)

Cursor(java.sql.Connection con, java.lang.String name, java.lang.String sql)
Default Constructor for Cursor

Method Summary

int	delete(CursorData cdata) Delete the data represented by the CursorData object from the database.
CursorData	getNewCursorData() Get an new CursorData object for this cursor, which has all the fields for this Cursor defined.
protected CursorData	getObject(CursorData prototype, java.sql.ResultSet rs) get a CursorData object filled from the current position in the ResultSet.
protected CursorData	getProtoType(java.sql.ResultSetMetaData rsMd) get a prototype on the basis of the SQL-statement for this Cursor, which is defined in the ResultSetMetaData.
java.util.Vector	select() Perform a select on the basis of the sql statement defined by this Cursor
java.util.Vector	select(Condition con) Deprecated. use select()
java.util.Vector	select(Condition con, boolean fieldsOnly) Deprecated. use select()
java.lang.String	toString() Overwritten to return the SQL statement that defines the Cursor
int	update(CursorData cdata) Update the data represented by the CursorData object from the database.

Methods inherited from class java.lang.Object

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

Field Detail

m_condition

protected java.lang.String m_condition

m_groupBy

protected java.lang.String m_groupBy

m_from

protected java.lang.String m_from

m_select

protected java.lang.String m_select

m_prep

protected java.sql.PreparedStatement m_prep

m_con

protected java.sql.Connection m_con

Constructor Detail

Cursor

public Cursor()

Deprecated. not used, use Cursor(Connection,String,String)

Constructor for Cursor.

Cursor

public Cursor(java.sql.Connection con,
              java.lang.String name,
              java.lang.String sql)

Default Constructor for Cursor

Parameters:

con - java.sql.Connection, a valid non-closed Connection

name - String, a distinct name for this Cursor

sql - String, a valid ANSI Sql string

Method Detail

delete

public int delete(CursorData cdata)
           throws java.lang.Exception

Delete the data represented by the CursorData object from the database.

Parameters:

cdata - CursorData, an object containing the results for the cursor

Returns:

int, the number of records affected by this delete command, should always be 1

Throws:

Exception, - thrown if the database delivers an Exception.

java.lang.Exception

select

public java.util.Vector select(Condition con)
                        throws java.lang.Exception

Deprecated. use select()

Perform a select on the basis of the sql statement defined by this Cursor

Parameters:

con - org.brains2b.sql.Condition, does not do anything.

Returns:

a Vector containing CursorData returned by the select statement

Throws:

java.lang.Exception - thrown if the database delivers an Exception

select

public java.util.Vector select(Condition con,
                               boolean fieldsOnly)
                        throws java.lang.Exception

Deprecated. use select()

Perform a select on the basis of the sql statement defined by this Cursor

Parameters:

con - org.brains2b.sql.Condition, does not do anything.

fieldsOnly - boolean, ignore the conditions to return all fields

Returns:

java.util.Vector containing CursorData returned by the select statement

Throws:

java.lang.Exception - thrown if the database delivers an Exception

select

public java.util.Vector select()
                        throws java.lang.Exception

Perform a select on the basis of the sql statement defined by this Cursor

Returns:

java.util.Vector containing CursorData returned by the select statement

Throws:

java.lang.Exception - thrown if the database delivers an Exception

update

public int update(CursorData cdata)
           throws java.lang.Exception

Update the data represented by the CursorData object from the database.

Parameters:

cdata - CursorData, an object containing the results for the cursor

Returns:

int, the number of records affected by this update command, should always be 1

Throws:

Exception, - thrown if the database delivers an Exception.

java.lang.Exception

toString

public java.lang.String toString()

Overwritten to return the SQL statement that defines the Cursor

Overrides:

toString in class java.lang.Object

See Also:

Object.toString()

getNewCursorData

public CursorData getNewCursorData()

Get an new CursorData object for this cursor, which has all the fields for this Cursor defined.

Returns:

CursorData, a new CursorData object which is basically a prototype retrieved from the database. Will return null if the underlying prototype cannot be returned, or if the database throws an Exception.

getProtoType

protected CursorData getProtoType(java.sql.ResultSetMetaData rsMd)
                           throws java.sql.SQLException

get a prototype on the basis of the SQL-statement for this Cursor, which is defined in the ResultSetMetaData.

Parameters:

rsMd - java.sql.ResultSetMetaData, created on the basis of this cursor SQL-statement

Returns:

CursorData, with all the fields defined but no values.

Throws:

SQLException, - thrown if the database delivers an SQLException.

java.sql.SQLException

getObject

protected CursorData getObject(CursorData prototype,
                               java.sql.ResultSet rs)
                        throws java.sql.SQLException

get a CursorData object filled from the current position in the ResultSet.

Parameters:

prototype - CursorData, object which functions as a prototype, will be cloned to function as return type.

rs - ResultSet, a resultset with a valid position

Returns:

CursorData, an object with all fields and values set.

Throws:

SQLException, - thrown if the resultset has no current position, or if the database delivers an SQLException

java.sql.SQLException