javax.swing.text

Class ZoneView

java.lang.Object

javax.swing.text.View

javax.swing.text.CompositeView

javax.swing.text.BoxView

javax.swing.text.ZoneView

All Implemented Interfaces:

SwingConstants

public class ZoneView
extends BoxView

A View implementation that delays loading of sub views until they are needed for display or internal transformations. This can be used for editors that need to handle large documents more effectivly than the standard BoxView.

Since:

1.3

Field Summary

Fields inherited from class javax.swing.text.View

BadBreakWeight, ExcellentBreakWeight, ForcedBreakWeight, GoodBreakWeight, X_AXIS, Y_AXIS

Fields inherited from interface javax.swing.SwingConstants

BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST

Constructor Summary

Constructors

Constructor and Description
ZoneView(Element element, int axis) Creates a new ZoneView for the specified element and axis.

Method Summary

Methods

Modifier and Type	Method and Description
protected View	createZone(int p0, int p1) Creates a zone for the specified range.
int	getMaximumZoneSize() Returns the maximum zone size.
int	getMaxZonesLoaded() Returns the number of zones that are allowed to be loaded.
protected int	getViewIndexAtPosition(int pos) Returns the index of the child view at the document position pos.
void	insertUpdate(DocumentEvent e, Shape a, ViewFactory vf) Receive notification about an insert update to the text model.
protected boolean	isZoneLoaded(View zone) Returns true when the specified zone is loaded, false otherwise.
protected void	loadChildren(ViewFactory vf) Overridden to not load all the child views.
void	removeUpdate(DocumentEvent e, Shape a, ViewFactory vf) Receive notification about a remove update to the text model.
void	setMaximumZoneSize(int size) Sets the maximum zone size.
void	setMaxZonesLoaded(int num) Sets the maximum number of zones that are allowed to be loaded at the same time.
protected void	unloadZone(View zone) This unloads the specified zone.
protected boolean	updateChildren(DocumentEvent.ElementChange ec, DocumentEvent e, ViewFactory vf) Updates the list of children that is returned by View.getView(int) and View.getViewCount().
protected void	zoneWasLoaded(View zone) Gets called after a zone has been loaded.

Methods inherited from class javax.swing.text.BoxView

baselineLayout, baselineRequirements, calculateMajorAxisRequirements, calculateMinorAxisRequirements, childAllocation, flipEastAndWestAtEnds, forwardUpdate, getAlignment, getAxis, getChildAllocation, getHeight, getMaximumSpan, getMinimumSpan, getOffset, getPreferredSpan, getResizeWeight, getSpan, getViewAtPoint, getWidth, isAfter, isAllocationValid, isBefore, isLayoutValid, layout, layoutChanged, layoutMajorAxis, layoutMinorAxis, modelToView, paint, paintChild, preferenceChanged, replace, setAxis, setSize, viewToModel

Methods inherited from class javax.swing.text.CompositeView

getBottomInset, getInsideAllocation, getLeftInset, getNextEastWestVisualPositionFrom, getNextNorthSouthVisualPositionFrom, getNextVisualPositionFrom, getRightInset, getTopInset, getView, getViewAtPosition, getViewCount, getViewIndex, modelToView, setInsets, setParagraphInsets, setParent

Methods inherited from class javax.swing.text.View

append, breakView, changedUpdate, createFragment, dump, forwardUpdateToView, getAttributes, getBreakWeight, getContainer, getDocument, getElement, getEndOffset, getGraphics, getParent, getStartOffset, getToolTipText, getViewFactory, getViewIndex, insert, isVisible, modelToView, remove, removeAll, updateLayout, viewToModel

Methods inherited from class java.lang.Object

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

Constructor Detail

ZoneView

public ZoneView(Element element,
        int axis)

Creates a new ZoneView for the specified element and axis.

Parameters:

element - the element for which to create a ZoneView

axis - the major layout axis for the box

Method Detail

setMaximumZoneSize

public void setMaximumZoneSize(int size)

Sets the maximum zone size. Note that zones might still become larger then the size specified when a singe child view is larger for itself, because zones are formed on child view boundaries.

Parameters:

size - the maximum zone size to set

See Also:

getMaximumZoneSize()

getMaximumZoneSize

public int getMaximumZoneSize()

Returns the maximum zone size. Note that zones might still become larger then the size specified when a singe child view is larger for itself, because zones are formed on child view boundaries.

Returns:

the maximum zone size

See Also:

setMaximumZoneSize(int)

setMaxZonesLoaded

public void setMaxZonesLoaded(int num)

Sets the maximum number of zones that are allowed to be loaded at the same time. If the new number of allowed zones is smaller then the previous settings, this unloads all zones the aren't allowed to be loaded anymore.

Parameters:

num - the number of zones allowed to be loaded at the same time

Throws:

IllegalArgumentException - if num <= 0

See Also:

getMaxZonesLoaded()

getMaxZonesLoaded

public int getMaxZonesLoaded()

Returns the number of zones that are allowed to be loaded.

Returns:

the number of zones that are allowed to be loaded

See Also:

setMaxZonesLoaded(int)

zoneWasLoaded

protected void zoneWasLoaded(View zone)

Gets called after a zone has been loaded. This unloads the oldest zone(s) when the maximum number of zones is reached.

Parameters:

zone - the zone that has been loaded

unloadZone

protected void unloadZone(View zone)

This unloads the specified zone. This is implemented to simply remove all child views from that zone.

Parameters:

zone - the zone to be unloaded

isZoneLoaded

protected boolean isZoneLoaded(View zone)

Returns true when the specified zone is loaded, false otherwise. The default implementation checks if the zone view has child elements.

Parameters:

zone - the zone view to check

Returns:

true when the specified zone is loaded, false otherwise

createZone

protected View createZone(int p0,
              int p1)

Creates a zone for the specified range. Subclasses can override this to provide a custom implementation for the zones.

Parameters:

p0 - the start of the range

p1 - the end of the range

Returns:

the zone

loadChildren

protected void loadChildren(ViewFactory vf)

Overridden to not load all the child views. This methods creates initial zones without actually loading them.

Overrides:

loadChildren in class CompositeView

Parameters:

vf - not used

See Also:

CompositeView.setParent(javax.swing.text.View)

getViewIndexAtPosition

protected int getViewIndexAtPosition(int pos)

Returns the index of the child view at the document position pos. This overrides the CompositeView implementation because the ZoneView does not provide a one to one mapping from Elements to Views.

Overrides:

getViewIndexAtPosition in class CompositeView

Parameters:

pos - the document position

Returns:

the index of the child view at the document position pos

insertUpdate

public void insertUpdate(DocumentEvent e,
                Shape a,
                ViewFactory vf)

Description copied from class: View

Receive notification about an insert update to the text model. The default implementation of this method does the following:

• Call View.updateChildren(javax.swing.event.DocumentEvent.ElementChange, javax.swing.event.DocumentEvent, javax.swing.text.ViewFactory) if the element that this view is responsible for has changed. This makes sure that the children can correctly represent the model.
• Call View.forwardUpdate(javax.swing.event.DocumentEvent.ElementChange, javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory). This forwards the DocumentEvent to the child views.
• Call View.updateLayout(javax.swing.event.DocumentEvent.ElementChange, javax.swing.event.DocumentEvent, java.awt.Shape). Gives the view a chance to either repair its layout, reschedule layout or do nothing at all.

Overrides:

insertUpdate in class View

Parameters:

e - the DocumentEvent that describes the change

a - the shape of the view

vf - the ViewFactory for creating child views

removeUpdate

public void removeUpdate(DocumentEvent e,
                Shape a,
                ViewFactory vf)

Description copied from class: View

Receive notification about a remove update to the text model. The default implementation of this method does the following:

• Call View.updateChildren(javax.swing.event.DocumentEvent.ElementChange, javax.swing.event.DocumentEvent, javax.swing.text.ViewFactory) if the element that this view is responsible for has changed. This makes sure that the children can correctly represent the model.
• Call View.forwardUpdate(javax.swing.event.DocumentEvent.ElementChange, javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory). This forwards the DocumentEvent to the child views.
• Call View.updateLayout(javax.swing.event.DocumentEvent.ElementChange, javax.swing.event.DocumentEvent, java.awt.Shape). Gives the view a chance to either repair its layout, reschedule layout or do nothing at all.

Overrides:

removeUpdate in class View

Parameters:

e - the DocumentEvent that describes the change

a - the shape of the view

vf - the ViewFactory for creating child views

updateChildren

protected boolean updateChildren(DocumentEvent.ElementChange ec,
                     DocumentEvent e,
                     ViewFactory vf)

Description copied from class: View

Updates the list of children that is returned by View.getView(int) and View.getViewCount(). Element that are specified as beeing added in the ElementChange record are assigned a view for using the ViewFactory. Views of Elements that are specified as beeing removed are removed from the list.

Overrides:

updateChildren in class View

Parameters:

ec - the ElementChange record that describes the change of the element

e - the DocumentEvent describing the change of the document model

vf - the ViewFactory to use for creating new views

Returns:

whether or not the child views represent the child elements of the element that this view is responsible for. Some views may create views that are responsible only for parts of the element that they are responsible for and should then return false.