sqlwrapper
Class QueryResult

java.lang.Object
  sqlwrapper.QueryResult

All Implemented Interfaces:

java.util.Iterator

public class QueryResult
extends java.lang.Object
implements java.util.Iterator

Implementation of the query ResultSet that supports pageable query for handling large data sets that does not fit into the memory.

Field Summary

private java.sql.ResultSet	currentPage
private int	currentPageInd
private java.util.ArrayList	currentRecord
private int	currentRecordInd
private int	numberOfPages
private int	numCols
private boolean	pageLoaded
private int	pageSize
private java.lang.String	query
private int	recordCount
private java.sql.Statement	stat

Constructor Summary

QueryResult(java.sql.Statement stat, java.lang.String sql)
Class constructor

Method Summary

boolean	hasNext() Returns false if resutSet pointer reaches the end of the set, returns true otherwise.
java.lang.Object	next() Extract the next data from the resultSet.
void	nextPage() Next page is retrieved from disk to memory
void	remove()
void	setPageSize(int pageSize) Set the maximum number of tuples that resides in a page

Methods inherited from class java.lang.Object

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

Field Detail

query

private java.lang.String query

stat

private java.sql.Statement stat

currentRecordInd

private int currentRecordInd

currentPageInd

private int currentPageInd

currentRecord

private java.util.ArrayList currentRecord

recordCount

private int recordCount

numCols

private int numCols

pageSize

private int pageSize

numberOfPages

private int numberOfPages

pageLoaded

private boolean pageLoaded

currentPage

private java.sql.ResultSet currentPage

Constructor Detail

QueryResult

public QueryResult(java.sql.Statement stat,
                   java.lang.String sql)
            throws java.sql.SQLException

Class constructor

Parameters:

stat - Statement object for executing sql query

sql - SQL query

Throws:

java.sql.SQLException

Method Detail

hasNext

public boolean hasNext()

Returns false if resutSet pointer reaches the end of the set, returns true otherwise.

Specified by:

hasNext in interface java.util.Iterator

Returns:

success

next

public java.lang.Object next()

Extract the next data from the resultSet. If the end of the currentPage is reached, next page is retrieved from disk to memory.

Specified by:

next in interface java.util.Iterator

Returns:

next tuple from the resultSet

nextPage

public void nextPage()
              throws java.sql.SQLException

Next page is retrieved from disk to memory

Throws:

java.sql.SQLException

setPageSize

public void setPageSize(int pageSize)

Set the maximum number of tuples that resides in a page

Parameters:

pageSize - number of tuples

remove

public void remove()

Specified by:

remove in interface java.util.Iterator