HasDataPresenter (Google Web Toolkit Javadoc)

java.lang.Object
- 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

Nested Classes
Modifier and Type	Class and Description
`(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

Fields
Modifier and Type	Field and Description
`(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

Constructors
Constructor and Description
`HasDataPresenter(HasData<T> display, HasDataPresenter.View<T> view, int pageSize, ProvidesKey<T> keyProvider)` Construct a new `HasDataPresenter`.

Method Summary

Methods
Modifier and Type	Method and Description
`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 `Range`s, 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 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

Class HasDataPresenter<T>

Nested Class Summary

Nested classes/interfaces inherited from interface com.google.gwt.user.cellview.client.HasKeyboardPagingPolicy

Nested classes/interfaces inherited from interface com.google.gwt.user.cellview.client.HasKeyboardSelectionPolicy

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

PAGE_INCREMENT

Constructor Detail

HasDataPresenter

Method Detail

addCellPreviewHandler

addLoadingStateChangeHandler

addRangeChangeHandler

addRowCountChangeHandler

clearKeyboardSelectedRowValue

clearSelectionModel

fireEvent

flush

getCurrentPageSize

getKeyboardPagingPolicy

getKeyboardSelectedRow

getKeyboardSelectedRowInView

getKeyboardSelectedRowValue

getKeyboardSelectionPolicy

getKeyProvider

getRowCount

getSelectionModel

getVisibleItem

getVisibleItemCount

getVisibleItems

getVisibleRange

hasPendingState

isEmpty

isRowCountExact

redraw

setKeyboardPagingPolicy

setKeyboardSelectedRow

setKeyboardSelectionPolicy

setRowCount

setRowCount

setRowData

setSelectionModel

setVisibleRange

setVisibleRange

setVisibleRangeAndClearData

scheduleFinally

calculateModifiedRanges