org.sormula.selector

Class PaginatedSelector<R,C>

java.lang.Object

org.sormula.selector.PaginatedSelector<R,C>

Type Parameters:

R - Class associated with a row in table

C - collection type for one page

All Implemented Interfaces:

java.lang.AutoCloseable

Direct Known Subclasses:

AbstractPaginatedListSelector

public class PaginatedSelector<R,C>
extends java.lang.Object
implements java.lang.AutoCloseable

The base class for all selectors that return pages of rows using some SelectOperation. The same select operation is used for all pages so that only one PreparedStatement is created for all pages.

Since:

4.3

Author:

Jeff Miller

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PaginatedSelector(int pageSize, boolean scrollSensitive) Constructs for a page size and scroll sensitivity.
	PaginatedSelector(int pageSize, SelectOperation<R,C> selectOperation) Constructs for a page size and select operation.
	PaginatedSelector(int pageSize, SelectOperation<R,C> selectOperation, boolean scrollSensitive) Constructs for a page size, select operation, and scroll sensitivity.

Method Summary

Modifier and Type	Method and Description
void	close() Closes the select operation with ScalarSelectOperation.close().
protected void	confirmExecuted()
void	execute() Executes the select operation and positions to the first page.
int	getPageNumber() Gets the page number that was set with setPageNumber(int), nextPage(), previousPage().
int	getPageSize() Gets the page size that was specified in the constructor.
protected void	init(SelectOperation<R,C> selectOperation)
boolean	isScrollSensitive() Gets the result set scroll sensitivity that was specified in the constructor.
void	nextPage() Move result set cursor to getPageNumber() + 1
void	previousPage() Move result set cursor to getPageNumber() - 1
C	selectPage() Selects rows for current page.
R	selectRow() Selects next row from the current page.
void	setPageNumber(int pageNumber) Positions result set cursor to a specific page.
protected void	topOfPage() Positions result set cursor to the top of the page.

Methods inherited from class java.lang.Object

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

Constructor Detail

PaginatedSelector

public PaginatedSelector(int pageSize,
                         SelectOperation<R,C> selectOperation)

Constructs for a page size and select operation. Scroll sensitivity is false.

Parameters:

pageSize - rows per page

selectOperation - the operation to select rows

PaginatedSelector

public PaginatedSelector(int pageSize,
                         SelectOperation<R,C> selectOperation,
                         boolean scrollSensitive)

Constructs for a page size, select operation, and scroll sensitivity.

Parameters:

pageSize - rows per page

selectOperation - the operation to select rows

scrollSensitive - true to use result set type of ResultSet.TYPE_SCROLL_SENSITIVE, false to use ResultSet.TYPE_SCROLL_INSENSITIVE

PaginatedSelector

protected PaginatedSelector(int pageSize,
                            boolean scrollSensitive)

Constructs for a page size and scroll sensitivity. Select operation must be set with init(SelectOperation). This constructor is for subclasses that initialize the select operation in a specialized way.

Parameters:

pageSize - rows per page

scrollSensitive - true to use result set type of ResultSet.TYPE_SCROLL_SENSITIVE, false to use ResultSet.TYPE_SCROLL_INSENSITIVE

Method Detail

init

protected void init(SelectOperation<R,C> selectOperation)

execute

public void execute()
             throws SelectorException

Executes the select operation and positions to the first page.

Throws:

SelectorException - if error

See Also:

ScalarSelectOperation.execute()

confirmExecuted

protected void confirmExecuted()
                        throws SelectorException

Throws:

SelectorException

getPageSize

public int getPageSize()

Gets the page size that was specified in the constructor.

Returns:

rows per page

isScrollSensitive

public boolean isScrollSensitive()

Gets the result set scroll sensitivity that was specified in the constructor.

Returns:

true if scrolling is sensitive to changes in the table; false if not

See Also:

Connection.prepareStatement(String, int, int)

getPageNumber

public int getPageNumber()

Gets the page number that was set with setPageNumber(int), nextPage(), previousPage().

Returns:

the page number to use for selectPage(), selectRow()

setPageNumber

public void setPageNumber(int pageNumber)
                   throws SelectorException

Positions result set cursor to a specific page. If page number is greater than the total number of pages, no exception will occur but selectPage() will be empty and selectRow() will return null.

Parameters:

pageNumber - position to specific page, pages less than 1 will cause an exception

Throws:

SelectorException - if error

See Also:

ScalarSelectOperation.positionAbsolute(int)

nextPage

public void nextPage()
              throws SelectorException

Move result set cursor to getPageNumber() + 1

Throws:

SelectorException - if error

previousPage

public void previousPage()
                  throws SelectorException

Move result set cursor to getPageNumber() - 1

Throws:

SelectorException - if error

selectPage

public C selectPage()
             throws SelectorException

Selects rows for current page. This method can be used multiple times to select the same page.

Returns:

collection of rows for the page; empty collection if page number is beyond the maximum page

Throws:

SelectorException - if error

selectRow

public R selectRow()
            throws SelectorException

Selects next row from the current page. Invoke setPageNumber(int) prior to selectRow() to start at top of page. Use this method instead of selectPage() if you would like to read one row at-a-time rather than the whole page.

Returns:

row or null if no more rows on the page

Throws:

SelectorException - if error

close

public void close()
           throws SelectorException

Closes the select operation with ScalarSelectOperation.close().

Specified by:

close in interface java.lang.AutoCloseable

Throws:

SelectorException

topOfPage

protected void topOfPage()
                  throws SelectorException

Positions result set cursor to the top of the page.

Throws:

SelectorException - if error