org.shept.org.springframework.beans.support
Class PagedListHolder<E>

java.lang.Object
  org.shept.org.springframework.beans.support.PagedListHolder<E>

All Implemented Interfaces:

Serializable, PageableList<E>

Direct Known Subclasses:

ChoiceListHolder

public class PagedListHolder<E>
extends Object
implements Serializable, PageableList<E>

This is an extended version of the original PagedListHolder as delivered by the spring framework. The original version has implemeted a fix sorting behavior which is done in memory and cannot (easily ?) be delegated to the dataSource to be performed by a database query.

The only thing we have changed is that we made most of the local variables protected instead of private so that this behaviour can be redefined in subclasses.

added getSortUsed() getterMethod
added implements PageableList();

--- The following comment is unchanged from the original version ----
PagedListHolder is a simple state holder for handling lists of objects, separating them into pages. Page numbering starts with 0.

This is mainly targetted at usage in web UIs. Typically, an instance will be instantiated with a list of beans, put into the session, and exported as model. The properties can all be set/get programmatically, but the most common way will be data binding, i.e. populating the bean from request parameters. The getters will mainly be used by the view.

Supports sorting the underlying list via a SortDefinition implementation, available as property "sort". By default, a MutableSortDefinition instance that toggles the ascending value on setting the same property again is used.

The data binding names have to be called "pageSize" and "sort.ascending", as expected by BeanWrapper. Note that the names and the nesting syntax match the respective JSTL EL expressions, like "myModelAttr.pageSize" and "myModelAttr.sort.ascending".

This class just provides support for an unmodifiable List of beans. If you need on-demand refresh because of Locale or filter changes, consider RefreshablePagedListHolder.

Since:

19.05.2003

Author:

Juergen Hoeller

See Also:

getPageList(), org.springframework.beans.support.RefreshablePagedListHolder, TODO LIST_BINDING_NAME und getListBindingName() remove ?, Serialized Form

Field Summary

private static int	DEFAULT_MAX_LINKED_PAGES
protected int	maxLinkedPages
protected int	newModelSize
protected Object	newModelTemplate
protected boolean	newPageSet
protected int	page
protected int	pageSize
protected Date	refreshDate
private static long	serialVersionUID
protected org.springframework.beans.support.SortDefinition	sort
protected org.springframework.beans.support.SortDefinition	sortUsed
private List<E>	source

Fields inherited from interface org.shept.org.springframework.beans.support.PageableList

DEFAULT_NEW_MODEL_SIZE, DEFAULT_PAGE_SIZE, LIST_BINDING_NAME

Constructor Summary

PagedListHolder()
Create a new holder instance.

PagedListHolder(List<E> source)
Create a new holder instance with the given source list, starting with a default sort definition (with "toggleAscendingOnProperty" activated).

PagedListHolder(List<E> source, org.springframework.beans.support.SortDefinition sort, Object newModelTemplate)
Create a new holder instance with the given source list.

Method Summary

protected Object	copyModel(Object model) Use Springs default bean copying implementation to obtain a shallow object copy
protected org.springframework.beans.support.SortDefinition	copySortDefinition(org.springframework.beans.support.SortDefinition s) Create a deep copy of the given sort definition, for use as state holder to compare a modified sort definition against.
protected void	doSort(List<E> src, org.springframework.beans.support.SortDefinition s) Actually perform sorting of the given source list, according to the given sort definition.
protected int	getFirstElementOnPage_orig()
int	getFirstElementOnPage() Modifications in getFirstElementOnPage() and getLastElementOnPage() are a workaround for a problem in jsp implementation that getLastElementOnPage() may not return -1 (numbers below 0) which is neccessary when the list is empty (because the first element will be 0 then and the last element must be below this value otherwise an unexisting element might be indexed)
int	getFirstLinkedPage() Return the first page to which create a link around the current page.
protected int	getLastElementOnPage_orig()
int	getLastElementOnPage() Modifications in getFirstElementOnPage() and getLastElementOnPage() are a workaround for a problem in jsp implementation that getLastElementOnPage() may not return -1 (numbers below 0) which is neccessary when the list is empty (because the first element will be 0 then and the last element must be below this value otherwise an unexisting element might be indexed)
int	getLastLinkedPage() Return the last page to which create a link around the current page.
String	getListBindingName() return the binding name of the list
int	getMaxLinkedPages() Return the maximum number of page links to a few pages around the current one.
protected List<E>	getNewModels()
int	getNewModelSize() get the new model template (for creating new objects)
Object	getNewModelTemplate() get the new model template (for creating new objects)
int	getNrOfElements() Return the total number of elements in the source list.
int	getPage() Return the current page number.
int	getPageCount() Return the number of pages for the current source list.
List<E>	getPageList() Return a sub-list representing the current page.
int	getPageSize() Return the current page size.
Date	getRefreshDate() Return the last time the list has been fetched from the source provider.
org.springframework.beans.support.SortDefinition	getSort() Return the sort definition for this holder.
org.springframework.beans.support.SortDefinition	getSortUsed()
List<E>	getSource() Return the source list for this holder.
boolean	isEol() Return if the underlying resultset is completely read (always true if the resultset is not based on cursors)
boolean	isFirstPage() Return if the current page is the first one.
boolean	isLastPage() Return if the current page is the last one.
boolean	isSortNeeded() Added to the original implementation so we can check for changes and refresh the view conditionally..
boolean	isVisible(Integer idx) Return if the given element index is within the range of the currently visible Page
void	nextPage() Switch to next page.
void	previousPage() Switch to previous page.
void	resort() Resort the list if necessary, i.e.
void	setMaxLinkedPages(int maxLinkedPages) Set the maximum number of page links to a few pages around the current one.
void	setNewModelSize(int newModelSize) Set the new model template (for creating new objects)
void	setNewModelTemplate(Object newModelTemplate) Set a model object as a template for creating new models.
void	setPage(int page) Set the current page number.
void	setPageSize(int pageSize) Set the current page size.
void	setSort(org.springframework.beans.support.SortDefinition sort) Set the sort definition for this holder.
void	setSource(List<E> source) Set the source list for this holder.
protected void	setSourceInternal(List<E> source)
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

DEFAULT_MAX_LINKED_PAGES

private static final int DEFAULT_MAX_LINKED_PAGES

See Also:

Constant Field Values

source

private List<E> source

refreshDate

protected transient Date refreshDate

sort

protected org.springframework.beans.support.SortDefinition sort

sortUsed

protected org.springframework.beans.support.SortDefinition sortUsed

pageSize

protected int pageSize

page

protected int page

newPageSet

protected transient boolean newPageSet

maxLinkedPages

protected int maxLinkedPages

newModelTemplate

protected Object newModelTemplate

newModelSize

protected int newModelSize

Constructor Detail

PagedListHolder

public PagedListHolder()

Create a new holder instance. You'll need to set a source list to be able to use the holder.

See Also:

setSource(java.util.List)

PagedListHolder

public PagedListHolder(List<E> source)

Create a new holder instance with the given source list, starting with a default sort definition (with "toggleAscendingOnProperty" activated).

Parameters:

source - the source List

See Also:

MutableSortDefinition.setToggleAscendingOnProperty(boolean)

PagedListHolder

public PagedListHolder(List<E> source,
                       org.springframework.beans.support.SortDefinition sort,
                       Object newModelTemplate)

Create a new holder instance with the given source list.

Parameters:

source - the source List

sort - the SortDefinition to start with

Method Detail

copySortDefinition

protected org.springframework.beans.support.SortDefinition copySortDefinition(org.springframework.beans.support.SortDefinition s)

Create a deep copy of the given sort definition, for use as state holder to compare a modified sort definition against.

Default implementation creates a MutableSortDefinition instance. Can be overridden in subclasses, in particular in case of custom extensions to the SortDefinition interface. Is allowed to return null, which means that no sort state will be held, triggering actual sorting for each resort call.

Parameters:

sort - the current SortDefinition object

Returns:

a deep copy of the SortDefinition object

See Also:

MutableSortDefinition.MutableSortDefinition(SortDefinition)

doSort

protected void doSort(List<E> src,
                      org.springframework.beans.support.SortDefinition s)

Actually perform sorting of the given source list, according to the given sort definition.

The default implementation uses Spring's PropertyComparator. Can be overridden in subclasses.

See Also:

PropertyComparator.sort(java.util.List, SortDefinition)

getFirstElementOnPage_orig

protected int getFirstElementOnPage_orig()

getFirstElementOnPage

public int getFirstElementOnPage()

Modifications in getFirstElementOnPage() and getLastElementOnPage() are a workaround for a problem in jsp implementation that getLastElementOnPage() may not return -1 (numbers below 0) which is neccessary when the list is empty (because the first element will be 0 then and the last element must be below this value otherwise an unexisting element might be indexed)

Specified by:

getFirstElementOnPage in interface PageableList<E>

getFirstLinkedPage

public int getFirstLinkedPage()

Description copied from interface: PageableList

Return the first page to which create a link around the current page.

Specified by:

getFirstLinkedPage in interface PageableList<E>

getLastElementOnPage_orig

protected int getLastElementOnPage_orig()

getLastElementOnPage

public int getLastElementOnPage()

Modifications in getFirstElementOnPage() and getLastElementOnPage() are a workaround for a problem in jsp implementation that getLastElementOnPage() may not return -1 (numbers below 0) which is neccessary when the list is empty (because the first element will be 0 then and the last element must be below this value otherwise an unexisting element might be indexed)

Specified by:

getLastElementOnPage in interface PageableList<E>

getLastLinkedPage

public int getLastLinkedPage()

Description copied from interface: PageableList

Return the last page to which create a link around the current page.

Specified by:

getLastLinkedPage in interface PageableList<E>

getMaxLinkedPages

public int getMaxLinkedPages()

Description copied from interface: PageableList

Return the maximum number of page links to a few pages around the current one.

Specified by:

getMaxLinkedPages in interface PageableList<E>

getNrOfElements

public int getNrOfElements()

Description copied from interface: PageableList

Return the total number of elements in the source list.

Specified by:

getNrOfElements in interface PageableList<E>

getPage

public int getPage()

Description copied from interface: PageableList

Return the current page number. Page numbering starts with 0.

Specified by:

getPage in interface PageableList<E>

getPageCount

public int getPageCount()

Description copied from interface: PageableList

Return the number of pages for the current source list.

Specified by:

getPageCount in interface PageableList<E>

getPageList

public List<E> getPageList()

Description copied from interface: PageableList

Return a sub-list representing the current page.

Specified by:

getPageList in interface PageableList<E>

getPageSize

public int getPageSize()

Description copied from interface: PageableList

Return the current page size.

Specified by:

getPageSize in interface PageableList<E>

getRefreshDate

public Date getRefreshDate()

Description copied from interface: PageableList

Return the last time the list has been fetched from the source provider.

Specified by:

getRefreshDate in interface PageableList<E>

getSort

public org.springframework.beans.support.SortDefinition getSort()

Description copied from interface: PageableList

Return the sort definition for this holder.

Specified by:

getSort in interface PageableList<E>

getSortUsed

public org.springframework.beans.support.SortDefinition getSortUsed()

Specified by:

getSortUsed in interface PageableList<E>

getSource

public List<E> getSource()

Description copied from interface: PageableList

Return the source list for this holder.

Specified by:

getSource in interface PageableList<E>

isFirstPage

public boolean isFirstPage()

Description copied from interface: PageableList

Return if the current page is the first one.

Specified by:

isFirstPage in interface PageableList<E>

isLastPage

public boolean isLastPage()

Description copied from interface: PageableList

Return if the current page is the last one.

Specified by:

isLastPage in interface PageableList<E>

isVisible

public boolean isVisible(Integer idx)

Description copied from interface: PageableList

Return if the given element index is within the range of the currently visible Page

Specified by:

isVisible in interface PageableList<E>

nextPage

public void nextPage()

Description copied from interface: PageableList

Switch to next page. Will stay on last page if already on last page.

Specified by:

nextPage in interface PageableList<E>

isSortNeeded

public boolean isSortNeeded()

Description copied from interface: PageableList

Added to the original implementation so we can check for changes and refresh the view conditionally..

Specified by:

isSortNeeded in interface PageableList<E>

previousPage

public void previousPage()

Description copied from interface: PageableList

Switch to previous page. Will stay on first page if already on first page.

Specified by:

previousPage in interface PageableList<E>

resort

public void resort()

Description copied from interface: PageableList

Resort the list if necessary, i.e. if the current sort instance isn't equal to the backed-up sortUsed instance.

Calls doSort to trigger actual sorting.

Specified by:

resort in interface PageableList<E>

See Also:

#doSort

setMaxLinkedPages

public void setMaxLinkedPages(int maxLinkedPages)

Set the maximum number of page links to a few pages around the current one.

setPage

public void setPage(int page)

Description copied from interface: PageableList

Set the current page number. Page numbering starts with 0.

Specified by:

setPage in interface PageableList<E>

setPageSize

public void setPageSize(int pageSize)

Description copied from interface: PageableList

Set the current page size. Resets the current page number if changed.

Default value is 10.

Specified by:

setPageSize in interface PageableList<E>

setSort

public void setSort(org.springframework.beans.support.SortDefinition sort)

Description copied from interface: PageableList

Set the sort definition for this holder. Typically an instance of MutableSortDefinition.

Specified by:

setSort in interface PageableList<E>

See Also:

MutableSortDefinition

setSource

public void setSource(List<E> source)

Description copied from interface: PageableList

Set the source list for this holder.

Specified by:

setSource in interface PageableList<E>

setSourceInternal

protected void setSourceInternal(List<E> source)

getNewModels

protected List<E> getNewModels()

copyModel

protected Object copyModel(Object model)

Use Springs default bean copying implementation to obtain a shallow object copy

Returns:

getNewModelTemplate

public Object getNewModelTemplate()

Description copied from interface: PageableList

get the new model template (for creating new objects)

Specified by:

getNewModelTemplate in interface PageableList<E>

Returns:

the newModelTemplate

setNewModelTemplate

public void setNewModelTemplate(Object newModelTemplate)

Set a model object as a template for creating new models.

Specified by:

setNewModelTemplate in interface PageableList<E>

getNewModelSize

public int getNewModelSize()

Description copied from interface: PageableList

get the new model template (for creating new objects)

Specified by:

getNewModelSize in interface PageableList<E>

Returns:

the newRowSize

setNewModelSize

public void setNewModelSize(int newModelSize)

Description copied from interface: PageableList

Set the new model template (for creating new objects)

Specified by:

setNewModelSize in interface PageableList<E>

Parameters:

newRowSize - the newRowSize to set

isEol

public boolean isEol()

Description copied from interface: PageableList

Return if the underlying resultset is completely read (always true if the resultset is not based on cursors)

Specified by:

isEol in interface PageableList<E>

getListBindingName

public String getListBindingName()

Description copied from interface: PageableList

return the binding name of the list

Specified by:

getListBindingName in interface PageableList<E>

toString

public String toString()

Overrides:

toString in class Object