org.objectweb.cjdbc.controller.virtualdatabase
Class ControllerResultSet

java.lang.Object
  org.objectweb.cjdbc.controller.virtualdatabase.ControllerResultSet

All Implemented Interfaces:

java.io.Serializable

public class ControllerResultSet

extends java.lang.Object

implements java.io.Serializable

A ControllerResultSet is a lightweight ResultSet for the controller side. It only contains row data and column metadata. The real ResultSet is constructed on by the driver on the client side from the ControllerResultSet information.

Version:

1.0

Author:

Emmanuel Cecchet

See Also:

DriverResultSet, Serialized Form

Field Summary

private java.lang.String	cursorName Cursor name for this ResultSet (not used yet)
private java.util.ArrayList	data The results
private java.sql.ResultSet	dbResultSet Backend ResultSet.
private boolean	dbResultSetClosed True if the underlying database ResultSet is closed
(package private) DriverResultSet	driverResultSet When streaming, hold a reference to the DriverResultSet we built so we don't have to re-compute everything.
private static java.util.ArrayList	EMPTY_LIST
private int	fetchSize Fetch size if we need to fetch only a subset of the ResultSet
private Field[]	fields The fields
private boolean	hasMoreData True if there is still more data to fetch from dbResultSet
private int	maxRows Maximum number of rows remaining to fetch
private java.sql.Statement	owningStatement Optional statement dbResultSet is attached to if in streaming mode

Constructor Summary

ControllerResultSet(AbstractRequest request, java.sql.ResultSet rs, MetadataCache metadataCache, java.sql.Statement s)
Build a C-JDBC ResultSet from a database specific ResultSet.

Method Summary

void	closeResultSet() Closes the database ResultSet to release the resource and garbage collect data.
void	fetchData() Fetch the next rows of data from dbResultSet according to fetchSize and maxRows parameters.
void	fetchData(int fetchSizeParam) Sets the fetch size and calls fetchData()
java.lang.String	getCursorName() Get the name of the SQL cursor used by this ResultSet
java.util.ArrayList	getData() Returns the data value.
Field[]	getFields() Returns the fields value.
boolean	hasMoreData() Returns the hasMoreData value.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_LIST

private static final java.util.ArrayList EMPTY_LIST

data

private java.util.ArrayList data

The results

fields

private Field[] fields

The fields

cursorName

private java.lang.String cursorName

Cursor name for this ResultSet (not used yet)

fetchSize

private int fetchSize

Fetch size if we need to fetch only a subset of the ResultSet

dbResultSet

private transient java.sql.ResultSet dbResultSet

Backend ResultSet. We need to hold it when streaming.

owningStatement

private transient java.sql.Statement owningStatement

Optional statement dbResultSet is attached to if in streaming mode

dbResultSetClosed

private boolean dbResultSetClosed

True if the underlying database ResultSet is closed

hasMoreData

private boolean hasMoreData

True if there is still more data to fetch from dbResultSet

maxRows

private int maxRows

Maximum number of rows remaining to fetch

driverResultSet

DriverResultSet driverResultSet

When streaming, hold a reference to the DriverResultSet we built so we don't have to re-compute everything.

Constructor Detail

ControllerResultSet

public ControllerResultSet(AbstractRequest request,
                           java.sql.ResultSet rs,
                           MetadataCache metadataCache,
                           java.sql.Statement s)
                    throws java.sql.SQLException

Build a C-JDBC ResultSet from a database specific ResultSet. The metadata can be retrieved from the MetadataCache if provided. If a metadata cache is provided but the data is not in the cache, the MetadataCache is updated accordingly. The remaining code is a straightforward copy of both metadata and data.

The statement used to execute the query will be closed when the ResultSet has been completely copied or when the ResultSet is closed while in streaming mode.

Parameters:

request - Request to which this ResultSet belongs

rs - The database specific ResultSet

metadataCache - MetadataCache (null if none)

s - Statement used to get rs

Throws:

java.sql.SQLException - if an error occurs

Method Detail

fetchData

public void fetchData(int fetchSizeParam)
               throws java.sql.SQLException

Sets the fetch size and calls fetchData()

Parameters:

fetchSizeParam - the number of rows to fetch

Throws:

java.sql.SQLException - if an error occurs

See Also:

fetchData()

fetchData

public void fetchData()
               throws java.sql.SQLException

Fetch the next rows of data from dbResultSet according to fetchSize and maxRows parameters. This methods directly updates the data and hasMoreData fields returned by getData() and hadMoreData() accessors.

Throws:

java.sql.SQLException - from the backend or if dbResultSet is closed. Maybe we should use a different type internally.

getData

public java.util.ArrayList getData()

Returns the data value.

Returns:

Returns the data.

getFields

public Field[] getFields()

Returns the fields value.

Returns:

Returns the fields.

getCursorName

public java.lang.String getCursorName()

Get the name of the SQL cursor used by this ResultSet

Returns:

the ResultSet's SQL cursor name.

hasMoreData

public boolean hasMoreData()

Returns the hasMoreData value.

Returns:

Returns the hasMoreData.

closeResultSet

public void closeResultSet()

Closes the database ResultSet to release the resource and garbage collect data.