com.ziclix.python.sql

Class DataHandler

java.lang.Object

com.ziclix.python.sql.DataHandler

Direct Known Subclasses:

FilterDataHandler, Jython22DataHandler

public class DataHandler
extends 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.

Author:

brian zimmer

Constructor Summary

Constructors

Constructor and Description
DataHandler() Handle most generic Java data types.

Method Summary

Methods

Modifier and Type	Method and Description
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) Consume the InputStream into an byte array and close the InputStream.
static String	read(Reader reader) Consume the Reader into a String and close the Reader.
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.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DataHandler

public DataHandler()

Handle most generic Java data types.

Method Detail

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

Throws:

SQLException

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

Throws:

SQLException - thrown if an exception occurs

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.

Throws:

SQLException

postExecute

public void postExecute(Statement stmt)
                 throws SQLException

A callback after successfully executing the statement.

Throws:

SQLException

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

Throws:

SQLException

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

Throws:

SQLException

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

Throws:

SQLException - if the type is unmappable

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

Throws:

SQLException - if the type is unmappable

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

Throws:

SQLException

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

Throws:

SQLException

read

public static final byte[] read(InputStream stream)

Consume the InputStream into an byte array and close the InputStream.

Returns:

the contents of the InputStream a byte[]

read

public static String read(Reader reader)

Consume the Reader into a String and close the Reader.

Returns:

the contents of the Reader as a String

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

__chain__

public PyObject __chain__()

Returns a list of datahandlers chained together through the use of delegation.

Returns:

a list of datahandlers

toString

public String toString()

Returns the classname of this datahandler.

Overrides:

toString in class Object