com.ziclix.python.sql

Class DataHandler

Known Direct Subclasses:
FilterDataHandler

public class DataHandler
extends java.lang.Object

The DataHandler is responsible mapping the JDBC data type to a Jython object. Depending on the version of the JDBC implementation and the particulars of the driver, the type mapping can be significantly different. This interface can also be used to change the behaviour of the default mappings provided by the cursor. This might be useful in handling more complicated data types such as BLOBs, CLOBs and Arrays.
Version:
$Revision: 3484 $
Authors:
brian zimmer
last revised by $Author: cgroves $

Constructor Summary

DataHandler()
Handle most generic Java data types.

Method Summary

PyObject
__chain__()
Returns a list of datahandlers chained together through the use of delegation.
static boolean
checkNull(PreparedStatement stmt, int index, PyObject object, int type)
Handles checking if the object is null or None and setting it on the statement.
String
getMetaDataName(PyObject name)
Some database vendors are case sensitive on calls to DatabaseMetaData, most notably Oracle.
Procedure
getProcedure(PyCursor cursor, PyObject name)
A factory method for determing the correct procedure class to use per the cursor type.
PyObject
getPyObject(CallableStatement stmt, int col, int type)
Given a CallableStatement, column and type, return the appropriate Jython object.
PyObject
getPyObject(ResultSet set, int col, int type)
Given a ResultSet, column and type, return the appropriate Jython object.
PyObject
getRowId(Statement stmt)
Returns the row id of the last executed statement.
static DataHandler
getSystemDataHandler()
Build the DataHandler chain depending on the VM.
void
postExecute(Statement stmt)
A callback after successfully executing the statement.
void
preExecute(Statement stmt)
A callback prior to each execution of the statement.
static byte[]
read(InputStream stream)
Since the driver needs to the know the length of all streams, read it into a byte[] array.
static String
read(Reader reader)
Read all the chars from the Reader into the String.
void
registerOut(CallableStatement statement, int index, int colType, int dataType, String dataTypeName)
Called when a stored procedure or function is executed and OUT parameters need to be registered with the statement.
void
setJDBCObject(PreparedStatement stmt, int index, PyObject object)
Any .execute() which uses prepared statements will receive a callback for deciding how to map the PyObject to the appropriate JDBC type.
void
setJDBCObject(PreparedStatement stmt, int index, PyObject object, int type)
Any .execute() which uses prepared statements will receive a callback for deciding how to map the PyObject to the appropriate JDBC type.
String
toString()
Returns the classname of this datahandler.

Constructor Details

DataHandler

public DataHandler()
Handle most generic Java data types.

Method Details

__chain__

public PyObject __chain__()
Returns a list of datahandlers chained together through the use of delegation.
Returns:
a list of datahandlers

checkNull

public static final boolean checkNull(PreparedStatement stmt,
                                      int index,
                                      PyObject object,
                                      int type)
            throws SQLException
Handles checking if the object is null or None and setting it on the statement.
Returns:
true if the object is null and was set on the statement, false otherwise

getMetaDataName

public String getMetaDataName(PyObject name)
Some database vendors are case sensitive on calls to DatabaseMetaData, most notably Oracle. This callback allows a DataHandler to affect the name.

getProcedure

public Procedure getProcedure(PyCursor cursor,
                              PyObject name)
            throws SQLException
A factory method for determing the correct procedure class to use per the cursor type.
Parameters:
cursor - an open cursor
name - the name of the procedure to invoke
Returns:
an instance of a Procedure

getPyObject

public PyObject getPyObject(CallableStatement stmt,
                            int col,
                            int type)
            throws SQLException
Given a CallableStatement, column and type, return the appropriate Jython object.
Parameters:
stmt - the CallableStatement
col - the column number (adjusted properly for JDBC)
type - the column type

getPyObject

public PyObject getPyObject(ResultSet set,
                            int col,
                            int type)
            throws SQLException
Given a ResultSet, column and type, return the appropriate Jython object.

Note: DO NOT iterate the ResultSet.

Parameters:
set - the current ResultSet set to the current row
col - the column number (adjusted properly for JDBC)
type - the column type

getRowId

public PyObject getRowId(Statement stmt)
            throws SQLException
Returns the row id of the last executed statement.
Parameters:
stmt - the current statement
Returns:
the row id of the last executed statement or None

getSystemDataHandler

public static final DataHandler getSystemDataHandler()
Build the DataHandler chain depending on the VM. This guarentees a DataHandler but might additionally chain a JDBC2.0 or JDBC3.0 implementation.
Returns:
a DataHandler configured for the VM version

postExecute

public void postExecute(Statement stmt)
            throws SQLException
A callback after successfully executing the statement.

preExecute

public void preExecute(Statement stmt)
            throws SQLException
A callback prior to each execution of the statement. If the statement is a PreparedStatement, all the parameters will have been set.

read

public static final byte[] read(InputStream stream)
Since the driver needs to the know the length of all streams, read it into a byte[] array.
Returns:
the stream as a byte[]

read

public static final String read(Reader reader)
Read all the chars from the Reader into the String.
Returns:
the contents of the Reader in a String

registerOut

public void registerOut(CallableStatement statement,
                        int index,
                        int colType,
                        int dataType,
                        String dataTypeName)
            throws SQLException
Called when a stored procedure or function is executed and OUT parameters need to be registered with the statement.
Parameters:
statement -
index - the JDBC offset column number
colType - the column as from DatabaseMetaData (eg, procedureColumnOut)
dataType - the JDBC datatype from Types
dataTypeName - the JDBC datatype name

setJDBCObject

public void setJDBCObject(PreparedStatement stmt,
                          int index,
                          PyObject object)
            throws SQLException
Any .execute() which uses prepared statements will receive a callback for deciding how to map the PyObject to the appropriate JDBC type.
Parameters:
stmt - the current PreparedStatement
index - the index for which this object is bound
object - the PyObject in question

setJDBCObject

public void setJDBCObject(PreparedStatement stmt,
                          int index,
                          PyObject object,
                          int type)
            throws SQLException
Any .execute() which uses prepared statements will receive a callback for deciding how to map the PyObject to the appropriate JDBC type. The type is the JDBC type as obtained from java.sql.Types.
Parameters:
stmt - the current PreparedStatement
index - the index for which this object is bound
object - the PyObject in question
type - the java.sql.Types for which this PyObject should be bound

toString

public String toString()
Returns the classname of this datahandler.

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