[Jython-checkins] CVS: jython/com/ziclix/python/sql/pipe/db BaseDB.java,1.2,1.3 DBSink.java,1.3,1.4 DBSource.java,1.2,1.3

[brian z. <bz...@us...>]

Update of /cvsroot/jython/jython/com/ziclix/python/sql/pipe/db
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv18519/com/ziclix/python/sql/pipe/db

Modified Files:
	BaseDB.java DBSink.java DBSource.java 
Log Message:
for the sake of better javadocs, fixed all warnings and updated ant build.xml; removed all tabs; removed Makefiles

Index: BaseDB.java
===================================================================
RCS file: /cvsroot/jython/jython/com/ziclix/python/sql/pipe/db/BaseDB.java,v
retrieving revision 1.2
retrieving revision 1.3
diff -C2 -d -r1.2 -r1.3
*** BaseDB.java	11 Jan 2002 21:46:01 -0000	1.2
--- BaseDB.java	23 Feb 2005 04:26:20 -0000	1.3
***************
*** 1,3 ****
- 
  /*
   * Jython Database Specification API 2.0
--- 1,2 ----
***************
*** 10,18 ****
  package com.ziclix.python.sql.pipe.db;
  
! import java.util.*;
! import java.lang.reflect.*;
! import org.python.core.*;
! import com.ziclix.python.sql.*;
! import com.ziclix.python.sql.handler.*;
  
  /**
--- 9,19 ----
  package com.ziclix.python.sql.pipe.db;
  
! import com.ziclix.python.sql.DataHandler;
! import com.ziclix.python.sql.PyConnection;
! import com.ziclix.python.sql.PyCursor;
! import com.ziclix.python.sql.zxJDBC;
! import org.python.core.Py;
! 
! import java.lang.reflect.Constructor;
  
  /**
***************
*** 24,95 ****
  public abstract class BaseDB {
  
! 	/** Field cursor */
! 	protected PyCursor cursor;
  
! 	/** Field dataHandler */
! 	protected Class dataHandler;
  
! 	/** Field tableName */
! 	protected String tableName;
  
! 	/** Field connection */
! 	protected PyConnection connection;
  
! 	/**
! 	 * Construct the helper.
! 	 */
! 	public BaseDB(PyConnection connection, Class dataHandler, String tableName) {
  
! 		this.tableName = tableName;
! 		this.dataHandler = dataHandler;
! 		this.connection = connection;
! 		this.cursor = this.cursor();
! 	}
  
! 	/**
! 	 * Create a new constructor and optionally bind a new DataHandler.  The new DataHandler must act as
! 	 * a Decorator, having a single argument constructor of another DataHandler.  The new DataHandler is
! 	 * then expected to delegate all calls to the original while enhancing the functionality in any matter
! 	 * desired.  This allows additional functionality without losing any previous work or requiring any
! 	 * complicated inheritance dependencies.
! 	 */
! 	protected PyCursor cursor() {
  
! 		PyCursor cursor = this.connection.cursor(true);
! 		DataHandler origDataHandler = cursor.getDataHandler(), newDataHandler = null;
  
! 		if ((origDataHandler != null) && (this.dataHandler != null)) {
! 			Constructor cons = null;
  
! 			try {
! 				Class[] args = new Class[1];
  
! 				args[0] = DataHandler.class;
! 				cons = this.dataHandler.getConstructor(args);
! 			} catch (Exception e) {
! 				return cursor;
! 			}
  
! 			if (cons == null) {
! 				String msg = zxJDBC.getString("invalidCons", new Object[]{ this.dataHandler.getName() });
  
! 				throw zxJDBC.makeException(msg);
! 			}
  
! 			try {
! 				Object[] args = new Object[1];
  
! 				args[0] = origDataHandler;
! 				newDataHandler = (DataHandler)cons.newInstance(args);
! 			} catch (Exception e) {
! 				return cursor;
! 			}
  
! 			if (newDataHandler != null) {
! 				cursor.__setattr__("datahandler", Py.java2py(newDataHandler));
! 			}
! 		}
  
! 		return cursor;
! 	}
  }
--- 25,104 ----
  public abstract class BaseDB {
  
!     /**
!      * Field cursor
!      */
!     protected PyCursor cursor;
  
!     /**
!      * Field dataHandler
!      */
!     protected Class dataHandler;
  
!     /**
!      * Field tableName
!      */
!     protected String tableName;
  
!     /**
!      * Field connection
!      */
!     protected PyConnection connection;
  
!     /**
!      * Construct the helper.
!      */
!     public BaseDB(PyConnection connection, Class dataHandler, String tableName) {
  
!         this.tableName = tableName;
!         this.dataHandler = dataHandler;
!         this.connection = connection;
!         this.cursor = this.cursor();
!     }
  
!     /**
!      * Create a new constructor and optionally bind a new DataHandler.  The new DataHandler must act as
!      * a Decorator, having a single argument constructor of another DataHandler.  The new DataHandler is
!      * then expected to delegate all calls to the original while enhancing the functionality in any matter
!      * desired.  This allows additional functionality without losing any previous work or requiring any
!      * complicated inheritance dependencies.
!      */
!     protected PyCursor cursor() {
  
!         PyCursor cursor = this.connection.cursor(true);
!         DataHandler origDataHandler = cursor.getDataHandler(), newDataHandler = null;
  
!         if ((origDataHandler != null) && (this.dataHandler != null)) {
!             Constructor cons = null;
  
!             try {
!                 Class[] args = new Class[1];
  
!                 args[0] = DataHandler.class;
!                 cons = this.dataHandler.getConstructor(args);
!             } catch (Exception e) {
!                 return cursor;
!             }
  
!             if (cons == null) {
!                 String msg = zxJDBC.getString("invalidCons", new Object[]{this.dataHandler.getName()});
  
!                 throw zxJDBC.makeException(msg);
!             }
  
!             try {
!                 Object[] args = new Object[1];
  
!                 args[0] = origDataHandler;
!                 newDataHandler = (DataHandler) cons.newInstance(args);
!             } catch (Exception e) {
!                 return cursor;
!             }
  
!             if (newDataHandler != null) {
!                 cursor.__setattr__("datahandler", Py.java2py(newDataHandler));
!             }
!         }
  
!         return cursor;
!     }
  }

Index: DBSink.java
===================================================================
RCS file: /cvsroot/jython/jython/com/ziclix/python/sql/pipe/db/DBSink.java,v
retrieving revision 1.3
retrieving revision 1.4
diff -C2 -d -r1.3 -r1.4
*** DBSink.java	29 Mar 2002 04:01:03 -0000	1.3
--- DBSink.java	23 Feb 2005 04:26:20 -0000	1.4
***************
*** 1,3 ****
- 
  /*
   * Jython Database Specification API 2.0
--- 1,2 ----
***************
*** 10,18 ****
  package com.ziclix.python.sql.pipe.db;
  
! import java.util.*;
! import org.python.core.*;
! import com.ziclix.python.sql.*;
! import com.ziclix.python.sql.pipe.*;
! import com.ziclix.python.sql.handler.*;
  
  /**
--- 9,23 ----
  package com.ziclix.python.sql.pipe.db;
  
! import com.ziclix.python.sql.PyConnection;
! import com.ziclix.python.sql.pipe.Sink;
! import com.ziclix.python.sql.zxJDBC;
! import org.python.core.Py;
! import org.python.core.PyDictionary;
! import org.python.core.PyList;
! import org.python.core.PyObject;
! import org.python.core.PyString;
! 
! import java.util.HashSet;
! import java.util.Set;
  
  /**
***************
*** 24,210 ****
  public class DBSink extends BaseDB implements Sink {
  
! 	/** Field sql */
! 	protected PyObject sql;
  
! 	/** Field exclude */
! 	protected Set exclude;
  
! 	/** Field rows */
! 	protected PyList rows;
  
! 	/** Field batchsize */
! 	protected int batchsize;
  
! 	/** Field bindings */
! 	protected PyObject bindings;
  
! 	/** Field indexedBindings */
! 	protected PyDictionary indexedBindings;
  
! 	/**
! 	 * Constructor for handling the consumption of data.
! 	 *
! 	 * @param connection the database connection
! 	 * @param dataHandler a custom DataHandler for the cursor, can be None
! 	 * @param tableName the table to insert the data
! 	 * @param exclude the columns to be excluded from insertion on the destination, all if None
! 	 * @param bindings the optional bindings for the destination, this allows morphing of types during the copy
! 	 * @param batchsize the optional batchsize for the inserts
! 	 */
! 	public DBSink(PyConnection connection, Class dataHandler, String tableName, PyObject exclude, PyObject bindings, int batchsize) {
  
! 		super(connection, dataHandler, tableName);
  
! 		this.sql = Py.None;
! 		this.rows = new PyList();
! 		this.bindings = bindings;
! 		this.batchsize = batchsize;
! 		this.exclude = new HashSet();
! 		this.indexedBindings = new PyDictionary();
  
! 		if (exclude != Py.None) {
! 			for (int i = 0; i < exclude.__len__(); i++) {
! 				PyObject lowered = Py.newString(((PyString)exclude.__getitem__(i)).lower());
  
! 				this.exclude.add(lowered);
! 			}
! 		}
! 	}
  
! 	/**
! 	 * Return true if the key (converted to lowercase) is not found in the exclude list.
! 	 */
! 	protected boolean excluded(PyObject key) {
  
! 		PyObject lowered = Py.newString(((PyString)key).lower());
  
! 		return this.exclude.contains(lowered);
! 	}
  
! 	/**
! 	 * Create the insert statement given the header row.
! 	 */
! 	protected void createSql(PyObject row) {
  
! 		// this should be the column info
! 		if ((row == Py.None) || (row.__len__() == 0)) {
  
! 			// if there are no columns, what's the point?
! 			throw zxJDBC.makeException(zxJDBC.getString("noColInfo"));
! 		}
  
! 		int index = 0, len = row.__len__();
! 		PyObject entry = Py.None, col = Py.None, pyIndex = Py.None;
! 		StringBuffer sb = new StringBuffer("insert into ").append(this.tableName).append(" (");
  
! 		/*
! 		 * Iterate through the columns and pull out the names for use in the insert
! 		 * statement and the types for use in the bindings.  The tuple is of the form
! 		 * (column name, column type).
! 		 */
! 		for (int i = 0; i < len - 1; i++) {
! 			entry = row.__getitem__(i);
! 			col = entry.__getitem__(0);
  
! 			if (!this.excluded(col)) {
  
! 				// add to the list
! 				sb.append(col).append(",");
  
! 				// add the binding
! 				pyIndex = Py.newInteger(index++);
  
! 				try {
! 					this.indexedBindings.__setitem__(pyIndex, this.bindings.__getitem__(col));
! 				} catch (Exception e) {
  
! 					// either a KeyError or this.bindings is None or null
! 					this.indexedBindings.__setitem__(pyIndex, entry.__getitem__(1));
! 				}
! 			}
! 		}
  
! 		entry = row.__getitem__(len - 1);
! 		col = entry.__getitem__(0);
  
! 		if (!this.excluded(col)) {
! 			sb.append(col);
  
! 			pyIndex = Py.newInteger(index++);
  
! 			try {
! 				this.indexedBindings.__setitem__(pyIndex, this.bindings.__getitem__(col));
! 			} catch (Exception e) {
  
! 				// either a KeyError or this.bindings is None or null
! 				this.indexedBindings.__setitem__(pyIndex, entry.__getitem__(1));
! 			}
! 		}
  
! 		sb.append(") values (");
  
! 		for (int i = 1; i < len; i++) {
! 			sb.append("?,");
! 		}
  
! 		sb.append("?)");
  
! 		if (index == 0) {
! 			throw zxJDBC.makeException(zxJDBC.ProgrammingError, zxJDBC.getString("excludedAllCols"));
! 		}
  
! 		this.sql = Py.newString(sb.toString());
! 	}
  
! 	/**
! 	 * Handle the row.  Insert the data into the correct table and columns.  No updates are done.
! 	 */
! 	public void row(PyObject row) {
  
! 		if (this.sql != Py.None) {
! 			if (this.batchsize <= 0) {
  
! 				// no batching, just go ahead each time
! 				this.cursor.execute(this.sql, row, this.indexedBindings, Py.None);
! 				this.connection.commit();
! 			} else {
! 				this.rows.append(row);
  
! 				int len = rows.__len__();
  
! 				if (len % this.batchsize == 0) {
! 					this.cursor.execute(this.sql, this.rows, this.indexedBindings, Py.None);
! 					this.connection.commit();
  
! 					this.rows = new PyList();
! 				}
! 			}
! 		} else {
! 			this.createSql(row);
! 		}
! 	}
  
! 	/**
! 	 * Method start
! 	 *
! 	 */
! 	public void start() {}
  
! 	/**
! 	 * Handles flushing any buffers and closes the cursor.
! 	 */
! 	public void end() {
  
! 		// finish what we started
! 		try {
! 			int len = this.rows.__len__();
  
! 			if (len > 0) {
! 				this.cursor.execute(this.sql, this.rows, this.indexedBindings, Py.None);
! 				this.connection.commit();
! 			}
! 		} finally {
! 			this.cursor.close();
! 		}
! 	}
  }
--- 29,227 ----
  public class DBSink extends BaseDB implements Sink {
  
!     /**
!      * Field sql
!      */
!     protected PyObject sql;
  
!     /**
!      * Field exclude
!      */
!     protected Set exclude;
  
!     /**
!      * Field rows
!      */
!     protected PyList rows;
  
!     /**
!      * Field batchsize
!      */
!     protected int batchsize;
  
!     /**
!      * Field bindings
!      */
!     protected PyObject bindings;
  
!     /**
!      * Field indexedBindings
!      */
!     protected PyDictionary indexedBindings;
  
!     /**
!      * Constructor for handling the consumption of data.
!      *
!      * @param connection  the database connection
!      * @param dataHandler a custom DataHandler for the cursor, can be None
!      * @param tableName   the table to insert the data
!      * @param exclude     the columns to be excluded from insertion on the destination, all if None
!      * @param bindings    the optional bindings for the destination, this allows morphing of types during the copy
!      * @param batchsize   the optional batchsize for the inserts
!      */
!     public DBSink(PyConnection connection, Class dataHandler, String tableName, PyObject exclude, PyObject bindings, int batchsize) {
  
!         super(connection, dataHandler, tableName);
  
!         this.sql = Py.None;
!         this.rows = new PyList();
!         this.bindings = bindings;
!         this.batchsize = batchsize;
!         this.exclude = new HashSet();
!         this.indexedBindings = new PyDictionary();
  
!         if (exclude != Py.None) {
!             for (int i = 0; i < exclude.__len__(); i++) {
!                 PyObject lowered = Py.newString(((PyString) exclude.__getitem__(i)).lower());
  
!                 this.exclude.add(lowered);
!             }
!         }
!     }
  
!     /**
!      * Return true if the key (converted to lowercase) is not found in the exclude list.
!      */
!     protected boolean excluded(PyObject key) {
  
!         PyObject lowered = Py.newString(((PyString) key).lower());
  
!         return this.exclude.contains(lowered);
!     }
  
!     /**
!      * Create the insert statement given the header row.
!      */
!     protected void createSql(PyObject row) {
  
!         // this should be the column info
!         if ((row == Py.None) || (row.__len__() == 0)) {
  
!             // if there are no columns, what's the point?
!             throw zxJDBC.makeException(zxJDBC.getString("noColInfo"));
!         }
  
!         int index = 0, len = row.__len__();
!         PyObject entry = Py.None, col = Py.None, pyIndex = Py.None;
!         StringBuffer sb = new StringBuffer("insert into ").append(this.tableName).append(" (");
  
!         /*
!          * Iterate through the columns and pull out the names for use in the insert
!          * statement and the types for use in the bindings.  The tuple is of the form
!          * (column name, column type).
!          */
!         for (int i = 0; i < len - 1; i++) {
!             entry = row.__getitem__(i);
!             col = entry.__getitem__(0);
  
!             if (!this.excluded(col)) {
  
!                 // add to the list
!                 sb.append(col).append(",");
  
!                 // add the binding
!                 pyIndex = Py.newInteger(index++);
  
!                 try {
!                     this.indexedBindings.__setitem__(pyIndex, this.bindings.__getitem__(col));
!                 } catch (Exception e) {
  
!                     // either a KeyError or this.bindings is None or null
!                     this.indexedBindings.__setitem__(pyIndex, entry.__getitem__(1));
!                 }
!             }
!         }
  
!         entry = row.__getitem__(len - 1);
!         col = entry.__getitem__(0);
  
!         if (!this.excluded(col)) {
!             sb.append(col);
  
!             pyIndex = Py.newInteger(index++);
  
!             try {
!                 this.indexedBindings.__setitem__(pyIndex, this.bindings.__getitem__(col));
!             } catch (Exception e) {
  
!                 // either a KeyError or this.bindings is None or null
!                 this.indexedBindings.__setitem__(pyIndex, entry.__getitem__(1));
!             }
!         }
  
!         sb.append(") values (");
  
!         for (int i = 1; i < len; i++) {
!             sb.append("?,");
!         }
  
!         sb.append("?)");
  
!         if (index == 0) {
!             throw zxJDBC.makeException(zxJDBC.ProgrammingError, zxJDBC.getString("excludedAllCols"));
!         }
  
!         this.sql = Py.newString(sb.toString());
!     }
  
!     /**
!      * Handle the row.  Insert the data into the correct table and columns.  No updates are done.
!      */
!     public void row(PyObject row) {
  
!         if (this.sql != Py.None) {
!             if (this.batchsize <= 0) {
  
!                 // no batching, just go ahead each time
!                 this.cursor.execute(this.sql, row, this.indexedBindings, Py.None);
!                 this.connection.commit();
!             } else {
!                 this.rows.append(row);
  
!                 int len = rows.__len__();
  
!                 if (len % this.batchsize == 0) {
!                     this.cursor.execute(this.sql, this.rows, this.indexedBindings, Py.None);
!                     this.connection.commit();
  
!                     this.rows = new PyList();
!                 }
!             }
!         } else {
!             this.createSql(row);
!         }
!     }
  
!     /**
!      * Method start
!      */
!     public void start() {
!     }
  
!     /**
!      * Handles flushing any buffers and closes the cursor.
!      */
!     public void end() {
  
!         // finish what we started
!         try {
!             int len = this.rows.__len__();
  
!             if (len > 0) {
!                 this.cursor.execute(this.sql, this.rows, this.indexedBindings, Py.None);
!                 this.connection.commit();
!             }
!         } finally {
!             this.cursor.close();
!         }
!     }
  }

Index: DBSource.java
===================================================================
RCS file: /cvsroot/jython/jython/com/ziclix/python/sql/pipe/db/DBSource.java,v
retrieving revision 1.2
retrieving revision 1.3
diff -C2 -d -r1.2 -r1.3
*** DBSource.java	29 Mar 2002 04:01:03 -0000	1.2
--- DBSource.java	23 Feb 2005 04:26:20 -0000	1.3
***************
*** 1,3 ****
- 
  /*
   * Jython Database Specification API 2.0
--- 1,2 ----
***************
*** 10,17 ****
  package com.ziclix.python.sql.pipe.db;
  
! import org.python.core.*;
! import com.ziclix.python.sql.*;
! import com.ziclix.python.sql.pipe.*;
! import com.ziclix.python.sql.handler.*;
  
  /**
--- 9,17 ----
  package com.ziclix.python.sql.pipe.db;
  
! import com.ziclix.python.sql.PyConnection;
! import com.ziclix.python.sql.pipe.Source;
! import org.python.core.Py;
! import org.python.core.PyObject;
! import org.python.core.PyTuple;
  
  /**
***************
*** 23,140 ****
  public class DBSource extends BaseDB implements Source {
  
! 	/** Field sql */
! 	protected String sql;
  
! 	/** Field sentHeader */
! 	protected boolean sentHeader;
  
! 	/** Field params, include */
! 	protected PyObject params, include;
  
! 	/**
! 	 * Constructor for handling the generation of data.
! 	 *
! 	 * @param connection the database connection
! 	 * @param dataHandler a custom DataHandler for the cursor, can be None
! 	 * @param tableName the table in question on the source database
! 	 * @param where an optional where clause, defaults to '(1=1)' if null
! 	 * @param include the columns to be queried from the source, '*' if None
! 	 * @param params optional params to substituted in the where clause
! 	 */
! 	public DBSource(PyConnection connection, Class dataHandler, String tableName, String where, PyObject include, PyObject params) {
  
! 		super(connection, dataHandler, tableName);
  
! 		this.params = params;
! 		this.include = include;
! 		this.sentHeader = false;
! 		this.sql = this.createSql(where);
! 	}
  
! 	/**
! 	 * Create the sql string given the where clause.
! 	 */
! 	protected String createSql(String where) {
  
! 		// create the sql statement, using the columns if available
! 		StringBuffer sb = new StringBuffer("select ");
  
! 		if ((this.include == Py.None) || (this.include.__len__() == 0)) {
! 			sb.append("*");
! 		} else {
! 			for (int i = 1; i < this.include.__len__(); i++) {
! 				sb.append(this.include.__getitem__(i)).append(",");
! 			}
  
! 			sb.append(this.include.__getitem__(this.include.__len__() - 1));
! 		}
  
! 		sb.append(" from ").append(this.tableName);
! 		sb.append(" where ").append((where == null) ? "(1=1)" : where);
  
! 		String sql = sb.toString();
  
! 		return sql;
! 	}
  
! 	/**
! 	 * Return the next row in the result set.  The first row returned will be column information.
! 	 */
! 	public PyObject next() {
  
! 		if (this.sentHeader) {
  
! 			// Py.None will be sent when all done, so this will close down the queue
! 			return this.cursor.fetchone();
! 		} else {
! 			this.cursor.execute(Py.newString(this.sql), this.params, Py.None, Py.None);
  
! 			PyObject description = this.cursor.__findattr__("description");
  
! 			// we can't insert if we don't know column names
! 			if ((description == Py.None) || (description.__len__() == 0)) {
  
! 				// let the destination worry about handling the empty set
! 				return Py.None;
! 			}
  
! 			int len = description.__len__();
! 			PyObject[] columns = new PyObject[len];
  
! 			for (int i = 0; i < len; i++) {
! 				PyObject[] colInfo = new PyObject[2];
  
! 				// col name
! 				colInfo[0] = description.__getitem__(i).__getitem__(0);
  
! 				// col type
! 				colInfo[1] = description.__getitem__(i).__getitem__(1);
! 				columns[i] = new PyTuple(colInfo);
! 			}
  
! 			PyObject row = new PyTuple(columns);
  
! 			Py.writeDebug("db-source", row.toString());
  
! 			this.sentHeader = true;
  
! 			return row;
! 		}
! 	}
  
! 	/**
! 	 * Method start
! 	 *
! 	 */
! 	public void start() {}
  
! 	/**
! 	 * Close the cursor.
! 	 */
! 	public void end() {
  
! 		if (this.cursor != null) {
! 			this.cursor.close();
! 		}
! 	}
  }
--- 23,146 ----
  public class DBSource extends BaseDB implements Source {
  
!     /**
!      * Field sql
!      */
!     protected String sql;
  
!     /**
!      * Field sentHeader
!      */
!     protected boolean sentHeader;
  
!     /**
!      * Field params, include
!      */
!     protected PyObject params, include;
  
!     /**
!      * Constructor for handling the generation of data.
!      *
!      * @param connection  the database connection
!      * @param dataHandler a custom DataHandler for the cursor, can be None
!      * @param tableName   the table in question on the source database
!      * @param where       an optional where clause, defaults to '(1=1)' if null
!      * @param include     the columns to be queried from the source, '*' if None
!      * @param params      optional params to substituted in the where clause
!      */
!     public DBSource(PyConnection connection, Class dataHandler, String tableName, String where, PyObject include, PyObject params) {
  
!         super(connection, dataHandler, tableName);
  
!         this.params = params;
!         this.include = include;
!         this.sentHeader = false;
!         this.sql = this.createSql(where);
!     }
  
!     /**
!      * Create the sql string given the where clause.
!      */
!     protected String createSql(String where) {
  
!         // create the sql statement, using the columns if available
!         StringBuffer sb = new StringBuffer("select ");
  
!         if ((this.include == Py.None) || (this.include.__len__() == 0)) {
!             sb.append("*");
!         } else {
!             for (int i = 1; i < this.include.__len__(); i++) {
!                 sb.append(this.include.__getitem__(i)).append(",");
!             }
  
!             sb.append(this.include.__getitem__(this.include.__len__() - 1));
!         }
  
!         sb.append(" from ").append(this.tableName);
!         sb.append(" where ").append((where == null) ? "(1=1)" : where);
  
!         String sql = sb.toString();
  
!         return sql;
!     }
  
!     /**
!      * Return the next row in the result set.  The first row returned will be column information.
!      */
!     public PyObject next() {
  
!         if (this.sentHeader) {
  
!             // Py.None will be sent when all done, so this will close down the queue
!             return this.cursor.fetchone();
!         } else {
!             this.cursor.execute(Py.newString(this.sql), this.params, Py.None, Py.None);
  
!             PyObject description = this.cursor.__findattr__("description");
  
!             // we can't insert if we don't know column names
!             if ((description == Py.None) || (description.__len__() == 0)) {
  
!                 // let the destination worry about handling the empty set
!                 return Py.None;
!             }
  
!             int len = description.__len__();
!             PyObject[] columns = new PyObject[len];
  
!             for (int i = 0; i < len; i++) {
!                 PyObject[] colInfo = new PyObject[2];
  
!                 // col name
!                 colInfo[0] = description.__getitem__(i).__getitem__(0);
  
!                 // col type
!                 colInfo[1] = description.__getitem__(i).__getitem__(1);
!                 columns[i] = new PyTuple(colInfo);
!             }
  
!             PyObject row = new PyTuple(columns);
  
!             Py.writeDebug("db-source", row.toString());
  
!             this.sentHeader = true;
  
!             return row;
!         }
!     }
  
!     /**
!      * Method start
!      */
!     public void start() {
!     }
  
!     /**
!      * Close the cursor.
!      */
!     public void end() {
  
!         if (this.cursor != null) {
!             this.cursor.close();
!         }
!     }
  }