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com.google.gwt.user.cellview.client
Class HasDataPresenter<T>

java.lang.Object
  extended by com.google.gwt.user.cellview.client.HasDataPresenter<T>
Type Parameters:
T - the data type of items in the list
All Implemented Interfaces:
HasHandlers, HasKeyboardPagingPolicy, HasKeyboardSelectionPolicy, HasCellPreviewHandlers<T>, HasData<T>, HasKeyProvider<T>, HasRows
 class HasDataPresenter<T>
extends java.lang.Object
implements HasData<T>, HasKeyProvider<T>, HasKeyboardPagingPolicy

Presenter implementation of HasData that presents data for various cell based widgets. This class contains most of the shared logic used by these widgets, making it easier to test the common code.

In proper MVP design, user code would interact with the presenter. However, that would complicate the widget code. Instead, each widget owns its own presenter and contains its own View. The widget forwards commands through to the presenter, which then updates the widget via the view. This keeps the user facing API simpler.

Updates are not pushed to the view immediately. Instead, the presenter collects updates and resolves them all in a finally command. This reduces the total number of DOM manipulations, and makes it easier to handle side effects in user code triggered by the rendering pass. The view is responsible for called flush() to force the presenter to synchronize the view when needed.

Nested Class Summary
(package private) static interface HasDataPresenter.ElementIterator
          An iterator over DOM elements.
(package private) static interface HasDataPresenter.View<T>
          The view that this presenter presents.
 
Nested classes/interfaces inherited from interface com.google.gwt.user.cellview.client.HasKeyboardPagingPolicy
HasKeyboardPagingPolicy.KeyboardPagingPolicy
 
Nested classes/interfaces inherited from interface com.google.gwt.user.cellview.client.HasKeyboardSelectionPolicy
HasKeyboardSelectionPolicy.KeyboardSelectionPolicy
 
Field Summary
(package private) static int PAGE_INCREMENT
          The number of rows to jump when PAGE_UP or PAGE_DOWN is pressed and the HasKeyboardPagingPolicy.KeyboardPagingPolicy is HasKeyboardPagingPolicy.KeyboardPagingPolicy.INCREASE_RANGE.
 
Constructor Summary
HasDataPresenter(HasData<T> display, HasDataPresenter.View<T> view, int pageSize, ProvidesKey<T> keyProvider)
          Construct a new HasDataPresenter.
 
Method Summary
 HandlerRegistration addCellPreviewHandler(CellPreviewEvent.Handler<T> handler)
          Adds a CellPreviewEvent handler.
 HandlerRegistration addLoadingStateChangeHandler(LoadingStateChangeEvent.Handler handler)
           
 HandlerRegistration addRangeChangeHandler(RangeChangeEvent.Handler handler)
          Add a RangeChangeEvent.Handler.
 HandlerRegistration addRowCountChangeHandler(RowCountChangeEvent.Handler handler)
          Add a RowCountChangeEvent.Handler.
(package private)  java.util.List<Range> calculateModifiedRanges(JsArrayInteger modifiedRows, int pageStart, int pageEnd)
          Combine the modified row indexes into as many as two Ranges, optimizing to have the fewest unmodified rows within the ranges.
 void clearKeyboardSelectedRowValue()
          Clear the row value associated with the keyboard selected row.
 void clearSelectionModel()
          Clear the SelectionModel without updating the view.
 void fireEvent(GwtEvent<?> event)
          Fires the given event to the handlers listening to the event's type.
 void flush()
          Flush pending changes to the view.
 int getCurrentPageSize()
          Get the current page size.
 HasKeyboardPagingPolicy.KeyboardPagingPolicy getKeyboardPagingPolicy()
          Get the HasKeyboardPagingPolicy.KeyboardPagingPolicy.
 int getKeyboardSelectedRow()
          Get the index of the keyboard selected row relative to the page start.
 int getKeyboardSelectedRowInView()
          Get the index of the keyboard selected row relative to the page start as it appears in the view, regardless of whether or not there is a pending change.
 T getKeyboardSelectedRowValue()
          Get the value that the user selected.
 HasKeyboardSelectionPolicy.KeyboardSelectionPolicy getKeyboardSelectionPolicy()
          Get the HasKeyboardSelectionPolicy.KeyboardSelectionPolicy.
 ProvidesKey<T> getKeyProvider()
          Return the key provider.
 int getRowCount()
          Get the overall data size.
 SelectionModel<? super T> getSelectionModel()
          Get the SelectionModel used by this HasData.
 T getVisibleItem(int indexOnPage)
          Get the row value at the specified visible index.
 int getVisibleItemCount()
          Get the number of visible items being displayed.
 java.util.List<T> getVisibleItems()
          Get an Iterable composed of all of the visible items.
 Range getVisibleRange()
          Return the range of data being displayed.
 boolean hasPendingState()
          Check whether or not there is a pending state.
 boolean isEmpty()
          Check whether or not the data set is empty.
 boolean isRowCountExact()
          Check if the total row count is exact, or an estimate.
 void redraw()
          Redraw the list with the current data.
protected  void scheduleFinally(Scheduler.ScheduledCommand command)
          Schedules the command.
 void setKeyboardPagingPolicy(HasKeyboardPagingPolicy.KeyboardPagingPolicy policy)
          Set the HasKeyboardPagingPolicy.KeyboardPagingPolicy.
 void setKeyboardSelectedRow(int index, boolean stealFocus, boolean forceUpdate)
          Set the row index of the keyboard selected element.
 void setKeyboardSelectionPolicy(HasKeyboardSelectionPolicy.KeyboardSelectionPolicy policy)
          Set the HasKeyboardSelectionPolicy.KeyboardSelectionPolicy.
 void setRowCount(int count)
          Set the exact total count of all rows.
 void setRowCount(int count, boolean isExact)
          Set the total count of all rows, specifying whether the count is exact or an estimate.
 void setRowData(int start, java.util.List<? extends T> values)
           Set a values associated with the rows in the visible range.
 void setSelectionModel(SelectionModel<? super T> selectionModel)
          Set the SelectionModel used by this HasData.
 void setVisibleRange(int start, int length)
          Set the visible range or rows.
 void setVisibleRange(Range range)
          Set the visible range or rows.
 void setVisibleRangeAndClearData(Range range, boolean forceRangeChangeEvent)
           Set the visible range and clear the current visible data.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

PAGE_INCREMENT

static final int PAGE_INCREMENT
The number of rows to jump when PAGE_UP or PAGE_DOWN is pressed and the HasKeyboardPagingPolicy.KeyboardPagingPolicy is HasKeyboardPagingPolicy.KeyboardPagingPolicy.INCREASE_RANGE.

See Also:
Constant Field Values
Constructor Detail

HasDataPresenter

public HasDataPresenter(HasData<T> display,
                        HasDataPresenter.View<T> view,
                        int pageSize,
                        ProvidesKey<T> keyProvider)
Construct a new HasDataPresenter.

Parameters:
display - the display that is being presented
view - the view implementation
pageSize - the default page size
Method Detail

addCellPreviewHandler

public HandlerRegistration addCellPreviewHandler(CellPreviewEvent.Handler<T> handler)
Description copied from interface: HasCellPreviewHandlers
Adds a CellPreviewEvent handler.

Specified by:
addCellPreviewHandler in interface HasCellPreviewHandlers<T>
Parameters:
handler - the handler
Returns:
the registration for the event

addLoadingStateChangeHandler

public HandlerRegistration addLoadingStateChangeHandler(LoadingStateChangeEvent.Handler handler)

addRangeChangeHandler

public HandlerRegistration addRangeChangeHandler(RangeChangeEvent.Handler handler)
Description copied from interface: HasRows
Add a RangeChangeEvent.Handler.

Specified by:
addRangeChangeHandler in interface HasRows
Parameters:
handler - the handler
Returns:
a HandlerRegistration to remove the handler

addRowCountChangeHandler

public HandlerRegistration addRowCountChangeHandler(RowCountChangeEvent.Handler handler)
Description copied from interface: HasRows
Add a RowCountChangeEvent.Handler.

Specified by:
addRowCountChangeHandler in interface HasRows
Parameters:
handler - the handler
Returns:
a HandlerRegistration to remove the handler

clearKeyboardSelectedRowValue

public void clearKeyboardSelectedRowValue()
Clear the row value associated with the keyboard selected row.

clearSelectionModel

public void clearSelectionModel()
Clear the SelectionModel without updating the view.

fireEvent

public void fireEvent(GwtEvent<?> event)
Description copied from interface: HasHandlers
Fires the given event to the handlers listening to the event's type.

Any exceptions thrown by handlers will be bundled into a UmbrellaException and then re-thrown after all handlers have completed. An exception thrown by a handler will not prevent other handlers from executing.

Specified by:
fireEvent in interface HasHandlers
Parameters:
event - the event
Throws:
java.lang.UnsupportedOperationException

flush

public void flush()
Flush pending changes to the view.

getCurrentPageSize

public int getCurrentPageSize()
Get the current page size. This is usually the page size, but can be less if the data size cannot fill the current page.

Returns:
the size of the current page

getKeyboardPagingPolicy

public HasKeyboardPagingPolicy.KeyboardPagingPolicy getKeyboardPagingPolicy()
Description copied from interface: HasKeyboardPagingPolicy
Get the HasKeyboardPagingPolicy.KeyboardPagingPolicy.

Specified by:
getKeyboardPagingPolicy in interface HasKeyboardPagingPolicy
Returns:
the paging policy
See Also:
HasKeyboardPagingPolicy.setKeyboardPagingPolicy(KeyboardPagingPolicy)

getKeyboardSelectedRow

public int getKeyboardSelectedRow()
Get the index of the keyboard selected row relative to the page start.

Returns:
the row index, or -1 if disabled

getKeyboardSelectedRowInView

public int getKeyboardSelectedRowInView()
Get the index of the keyboard selected row relative to the page start as it appears in the view, regardless of whether or not there is a pending change.

Returns:
the row index, or -1 if disabled

getKeyboardSelectedRowValue

public T getKeyboardSelectedRowValue()
Get the value that the user selected.

Returns:
the value, or null if a value was not selected

getKeyboardSelectionPolicy

public HasKeyboardSelectionPolicy.KeyboardSelectionPolicy getKeyboardSelectionPolicy()
Description copied from interface: HasKeyboardSelectionPolicy
Get the HasKeyboardSelectionPolicy.KeyboardSelectionPolicy.

Specified by:
getKeyboardSelectionPolicy in interface HasKeyboardSelectionPolicy
Returns:
the selection policy
See Also:
HasKeyboardSelectionPolicy.setKeyboardSelectionPolicy(KeyboardSelectionPolicy)

getKeyProvider

public ProvidesKey<T> getKeyProvider()
Description copied from interface: HasKeyProvider
Return the key provider.

Specified by:
getKeyProvider in interface HasKeyProvider<T>
Returns:
the ProvidesKey instance

getRowCount

public int getRowCount()
Get the overall data size.

Specified by:
getRowCount in interface HasRows
Returns:
the data size
See Also:
HasRows.setRowCount(int)

getSelectionModel

public SelectionModel<? super T> getSelectionModel()
Description copied from interface: HasData
Get the SelectionModel used by this HasData.

Specified by:
getSelectionModel in interface HasData<T>
Returns:
the SelectionModel
See Also:
HasData.setSelectionModel(SelectionModel)

getVisibleItem

public T getVisibleItem(int indexOnPage)
Description copied from interface: HasData
Get the row value at the specified visible index. Index 0 corresponds to the first item on the page.

Specified by:
getVisibleItem in interface HasData<T>
Parameters:
indexOnPage - the index on the page
Returns:
the row value

getVisibleItemCount

public int getVisibleItemCount()
Description copied from interface: HasData
Get the number of visible items being displayed. Note that this value might be less than the page size if there is not enough data to fill the page.

Specified by:
getVisibleItemCount in interface HasData<T>
Returns:
the number of visible items on the page

getVisibleItems

public java.util.List<T> getVisibleItems()
Description copied from interface: HasData
Get an Iterable composed of all of the visible items.

Specified by:
getVisibleItems in interface HasData<T>
Returns:
an Iterable instance

getVisibleRange

public Range getVisibleRange()
Return the range of data being displayed.

Specified by:
getVisibleRange in interface HasRows
Returns:
the visible range
See Also:
HasRows.setVisibleRange(Range), HasRows.setVisibleRange(int, int)

hasPendingState

public boolean hasPendingState()
Check whether or not there is a pending state. If there is a pending state, views might skip DOM updates and wait for the new data to be rendered when the pending state is resolved.

Returns:
true if there is a pending state, false if not

isEmpty

public boolean isEmpty()
Check whether or not the data set is empty. That is, the row count is exactly 0.

Returns:
true if data set is empty

isRowCountExact

public boolean isRowCountExact()
Description copied from interface: HasRows
Check if the total row count is exact, or an estimate.

Specified by:
isRowCountExact in interface HasRows
Returns:
true if exact, false if an estimate

redraw

public void redraw()
Redraw the list with the current data.

setKeyboardPagingPolicy

public void setKeyboardPagingPolicy(HasKeyboardPagingPolicy.KeyboardPagingPolicy policy)
Description copied from interface: HasKeyboardPagingPolicy
Set the HasKeyboardPagingPolicy.KeyboardPagingPolicy.

Specified by:
setKeyboardPagingPolicy in interface HasKeyboardPagingPolicy
Parameters:
policy - the paging policy
See Also:
HasKeyboardPagingPolicy.getKeyboardPagingPolicy()

setKeyboardSelectedRow

public void setKeyboardSelectedRow(int index,
                                   boolean stealFocus,
                                   boolean forceUpdate)
Set the row index of the keyboard selected element.

Parameters:
index - the row index
stealFocus - true to steal focus
forceUpdate - force the update even if the row didn't change

setKeyboardSelectionPolicy

public void setKeyboardSelectionPolicy(HasKeyboardSelectionPolicy.KeyboardSelectionPolicy policy)
Description copied from interface: HasKeyboardSelectionPolicy
Set the HasKeyboardSelectionPolicy.KeyboardSelectionPolicy.

Specified by:
setKeyboardSelectionPolicy in interface HasKeyboardSelectionPolicy
Parameters:
policy - the selection policy
See Also:
HasKeyboardSelectionPolicy.getKeyboardSelectionPolicy()

setRowCount

public final void setRowCount(int count)
Description copied from interface: HasRows
Set the exact total count of all rows. This method defers to HasRows.setRowCount(int, boolean).

Specified by:
setRowCount in interface HasRows
Parameters:
count - the exact total count
Throws:
java.lang.UnsupportedOperationException
See Also:
HasRows.getRowCount()

setRowCount

public void setRowCount(int count,
                        boolean isExact)
Description copied from interface: HasRows
Set the total count of all rows, specifying whether the count is exact or an estimate.

Specified by:
setRowCount in interface HasRows
Parameters:
count - the total count
isExact - true if the count is exact, false if an estimate
See Also:
HasRows.getRowCount()

setRowData

public void setRowData(int start,
                       java.util.List<? extends T> values)
Description copied from interface: HasData

Set a values associated with the rows in the visible range.

This method does not replace all rows in the display; it replaces the row values starting at the specified start index through the length of the specified values. You must call HasRows.setRowCount(int) to set the total number of rows in the display. You should also use HasRows.setRowCount(int) to remove rows when the total number of rows decreases.

Specified by:
setRowData in interface HasData<T>
Parameters:
start - the start index of the data
values - the values within the range

setSelectionModel

public void setSelectionModel(SelectionModel<? super T> selectionModel)
Description copied from interface: HasData
Set the SelectionModel used by this HasData.

Specified by:
setSelectionModel in interface HasData<T>
Parameters:
selectionModel - the SelectionModel
See Also:
HasData.getSelectionModel()

setVisibleRange

public final void setVisibleRange(int start,
                                  int length)
Description copied from interface: HasRows
Set the visible range or rows. This method defers to HasRows.setVisibleRange(Range).

Specified by:
setVisibleRange in interface HasRows
Parameters:
start - the start index
length - the length
Throws:
java.lang.UnsupportedOperationException
See Also:
HasRows.getVisibleRange()

setVisibleRange

public void setVisibleRange(Range range)
Description copied from interface: HasRows
Set the visible range or rows.

Specified by:
setVisibleRange in interface HasRows
Parameters:
range - the visible range
See Also:
HasRows.getVisibleRange()

setVisibleRangeAndClearData

public void setVisibleRangeAndClearData(Range range,
                                        boolean forceRangeChangeEvent)
Description copied from interface: HasData

Set the visible range and clear the current visible data.

If the second argument forceRangeChangeEvent is true, a RangeChangeEvent will be fired even if the range does not change. If false, a RangeChangeEvent will only be fired if the range changes.

Specified by:
setVisibleRangeAndClearData in interface HasData<T>
Parameters:
range - the new Range
forceRangeChangeEvent - true to fire a RangeChangeEvent even if the Range doesn't change

scheduleFinally

protected void scheduleFinally(Scheduler.ScheduledCommand command)
Schedules the command.

Protected so that subclasses can override to use an alternative scheduler.

Parameters:
command - the command to execute

calculateModifiedRanges

java.util.List<Range> calculateModifiedRanges(JsArrayInteger modifiedRows,
                                              int pageStart,
                                              int pageEnd)
Combine the modified row indexes into as many as two Ranges, optimizing to have the fewest unmodified rows within the ranges. Using two ranges covers the most common use cases of selecting one row, selecting a range, moving selection from one row to another, or moving keyboard selection.

Visible for testing.

This method has the side effect of sorting the modified rows.

Parameters:
modifiedRows - the unordered indexes of modified rows
Returns:
up to two ranges that encompass the modified rows
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GWT 2.7.0
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