com.ziclix.python.sql
Class DataHandler

java.lang.Object
  |
  +--com.ziclix.python.sql.DataHandler
Direct Known 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: 1.8 $
Author:
brian zimmer, last revised by $Author: bzimmer $

Constructor Summary
DataHandler()
          Handle most generic Java data types.
 
Method Summary
static boolean checkNull(java.sql.PreparedStatement stmt, int index, PyObject object, int type)
          Handles checking if the object is null or None and setting it on the statement.
 java.lang.String getMetaDataName(PyObject name)
          Some database vendors are case sensitive on calls to DatabaseMetaData, most notably Oracle.
 Procedure getProcedure(PyCursor cursor, PyObject name)
           
 PyObject getPyObject(java.sql.CallableStatement stmt, int col, int type)
          Given a CallableStatement, column and type, return the appropriate Jython object.
 PyObject getPyObject(java.sql.ResultSet set, int col, int type)
          Given a ResultSet, column and type, return the appropriate Jython object.
 PyObject getRowId(java.sql.Statement stmt)
          Returns the row id of the last executed statement.
static DataHandler getSystemDataHandler()
          Build the DataHandler chain depending on the VM.
 void postExecute(java.sql.Statement stmt)
          A callback after successfully executing the statement.
 void preExecute(java.sql.Statement stmt)
          A callback prior to each execution of the statement.
static byte[] read(java.io.InputStream stream)
          Since the driver needs to the know the length of all streams, read it into a byte[] array.
static java.lang.String read(java.io.Reader reader)
          Read all the chars from the Reader into the String.
 void registerOut(java.sql.CallableStatement statement, int index, int colType, int dataType, java.lang.String dataTypeName)
          Called when a stored procedure or function is executed and OUT parameters need to be registered with the statement.
 void setJDBCObject(java.sql.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(java.sql.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.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DataHandler

public DataHandler()
Handle most generic Java data types.
Method Detail

getMetaDataName

public java.lang.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.
Parameters:
PyString - name
Returns:
String

getProcedure

public Procedure getProcedure(PyCursor cursor,
                              PyObject name)
                       throws java.sql.SQLException

getRowId

public PyObject getRowId(java.sql.Statement stmt)
                  throws java.sql.SQLException
Returns the row id of the last executed statement.
Parameters:
Statement - stmt
Returns:
PyObject
Throws:
java.sql.SQLException -  

preExecute

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

postExecute

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

setJDBCObject

public void setJDBCObject(java.sql.PreparedStatement stmt,
                          int index,
                          PyObject object)
                   throws java.sql.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
Throws:
java.sql.SQLException -  

setJDBCObject

public void setJDBCObject(java.sql.PreparedStatement stmt,
                          int index,
                          PyObject object,
                          int type)
                   throws java.sql.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
Throws:
java.sql.SQLException -  

getPyObject

public PyObject getPyObject(java.sql.ResultSet set,
                            int col,
                            int type)
                     throws java.sql.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
Throws:
java.sql.SQLException - if the type is unmappable

getPyObject

public PyObject getPyObject(java.sql.CallableStatement stmt,
                            int col,
                            int type)
                     throws java.sql.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
Throws:
java.sql.SQLException - if the type is unmappable

registerOut

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

checkNull

public static final boolean checkNull(java.sql.PreparedStatement stmt,
                                      int index,
                                      PyObject object,
                                      int type)
                               throws java.sql.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

read

public static final byte[] read(java.io.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 java.lang.String read(java.io.Reader reader)
Read all the chars from the Reader into the String.
Returns:
the contents of the Reader in a String

getSystemDataHandler

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


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