JavaTM 2 Platform
Std. Ed. v1.3.1

javax.swing.text
Class BoxView

java.lang.Object
  |
  +--javax.swing.text.View
        |
        +--javax.swing.text.CompositeView
              |
              +--javax.swing.text.BoxView
All Implemented Interfaces:
SwingConstants
Direct Known Subclasses:
BlockView, FlowView, TableView, TableView.TableCell, TableView.TableRow, WrappedPlainView, ZoneView

public class BoxView
extends CompositeView

A view that arranges its children into a box shape by tiling it's children along an axis. The box is somewhat like that found in TeX where there is alignment of the children, flexibility of the children is considered, etc. This is considered an useful building block that might be useful to represent things like a collection of lines, paragraphs, lists, columns, pages, etc.


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, NORTH, NORTH_EAST, NORTH_WEST, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST
 
Constructor Summary
BoxView(Element elem, int axis)
          Constructs a BoxView.
 
Method Summary
protected  void baselineLayout(int targetSpan, int axis, int[] offsets, int[] spans)
           
protected  SizeRequirements baselineRequirements(int axis, SizeRequirements r)
           
protected  SizeRequirements calculateMajorAxisRequirements(int axis, SizeRequirements r)
           
protected  SizeRequirements calculateMinorAxisRequirements(int axis, SizeRequirements r)
           
protected  void childAllocation(int index, Rectangle alloc)
          Allocates a region for a child view.
protected  boolean flipEastAndWestAtEnds(int position, Position.Bias bias)
          Subclasses may wish to subclass this and conditionally return true based on the position.
protected  void forwardUpdate(DocumentEvent.ElementChange ec, DocumentEvent e, Shape a, ViewFactory f)
          Forward the given DocumentEvent to the child views that need to be notified of the change to the model.
 float getAlignment(int axis)
          Determines the desired alignment for this view along an axis.
 int getAxis()
          Fetch the axis property.
 Shape getChildAllocation(int index, Shape a)
          Fetches the allocation for the given child view.
 int getHeight()
          The current height of the box.
 float getMaximumSpan(int axis)
          Determines the maximum span for this view along an axis.
 float getMinimumSpan(int axis)
          Determines the minimum span for this view along an axis.
protected  int getOffset(int axis, int childIndex)
          Fetch the offset of a particular childs current layout
 float getPreferredSpan(int axis)
          Determines the preferred span for this view along an axis.
 int getResizeWeight(int axis)
          Gets the resize weight.
protected  int getSpan(int axis, int childIndex)
          Fetch the span of a particular childs current layout
protected  View getViewAtPoint(int x, int y, Rectangle alloc)
          Fetches the child view at the given point.
 int getWidth()
          The current width of the box.
protected  boolean isAfter(int x, int y, Rectangle innerAlloc)
          Determines if a point falls after an allocated region.
protected  boolean isAllocationValid()
          Are the allocations for the children still valid?
protected  boolean isBefore(int x, int y, Rectangle innerAlloc)
          Determines if a point falls before an allocated region.
protected  void layout(int width, int height)
          Performs layout of the children.
 void layoutChanged(int axis)
          Invalidate the layout along an axis.
protected  void layoutMajorAxis(int targetSpan, int axis, int[] offsets, int[] spans)
          Perform layout for the major axis of the box (i.e.
protected  void layoutMinorAxis(int targetSpan, int axis, int[] offsets, int[] spans)
          Perform layout for the minor axis of the box (i.e.
 Shape modelToView(int pos, Shape a, Position.Bias b)
          Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.
 void paint(Graphics g, Shape allocation)
          Renders using the given rendering surface and area on that surface.
protected  void paintChild(Graphics g, Rectangle alloc, int index)
          Paints a child.
 void preferenceChanged(View child, boolean width, boolean height)
          This is called by a child to indicated its preferred span has changed.
 void replace(int index, int length, View[] elems)
          Invalidates the layout and resizes the cache of requests/allocations.
 void setAxis(int axis)
          Set the axis property.
 void setSize(float width, float height)
          Sets the size of the view.
 int viewToModel(float x, float y, Shape a, Position.Bias[] bias)
          Provides a mapping from the view coordinate space to the logical coordinate space of the model.
 
Methods inherited from class javax.swing.text.CompositeView
getBottomInset, getInsideAllocation, getLeftInset, getNextEastWestVisualPositionFrom, getNextNorthSouthVisualPositionFrom, getNextVisualPositionFrom, getRightInset, getTopInset, getView, getViewAtPosition, getViewCount, getViewIndex, getViewIndexAtPosition, loadChildren, modelToView, setInsets, setParagraphInsets, setParent
 
Methods inherited from class javax.swing.text.View
append, breakView, changedUpdate, createFragment, forwardUpdateToView, getAttributes, getBreakWeight, getContainer, getDocument, getElement, getEndOffset, getGraphics, getParent, getStartOffset, getViewFactory, insert, insertUpdate, isVisible, modelToView, remove, removeAll, removeUpdate, updateChildren, updateLayout, viewToModel
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

BoxView

public BoxView(Element elem,
               int axis)
Constructs a BoxView.
Parameters:
elem - the element this view is responsible for
axis - either View.X_AXIS or View.Y_AXIS
Method Detail

getAxis

public int getAxis()
Fetch the axis property.
Returns:
the major axis of the box, either View.X_AXIS or View.Y_AXIS.

setAxis

public void setAxis(int axis)
Set the axis property.
Parameters:
axis - either View.X_AXIS or View.Y_AXIS

layoutChanged

public void layoutChanged(int axis)
Invalidate the layout along an axis. This happens automatically if the preferences have changed for any of the child views. In some cases the layout may need to be recalculated when the preferences have not changed. The layout can be marked as invalid by calling this method. The layout will be updated the next time the setSize method is called on this view (typically in paint).
Parameters:
axis - either View.X_AXIS or View.Y_AXIS

paintChild

protected void paintChild(Graphics g,
                          Rectangle alloc,
                          int index)
Paints a child. By default that is all it does, but a subclass can use this to paint things relative to the child.
Parameters:
g - the graphics context
alloc - the allocated region to paint into
index - the child index, >= 0 && < getViewCount()

replace

public void replace(int index,
                    int length,
                    View[] elems)
Invalidates the layout and resizes the cache of requests/allocations. The child allocations can still be accessed for the old layout, but the new children will have an offset and span of 0.
Overrides:
replace in class CompositeView
Parameters:
index - the starting index into the child views to insert the new views. This should be a value >= 0 and <= getViewCount.
length - the number of existing child views to remove. This should be a value >= 0 and <= (getViewCount() - offset).
views - the child views to add. This value can be null to indicate no children are being added (useful to remove).

forwardUpdate

protected void forwardUpdate(DocumentEvent.ElementChange ec,
                             DocumentEvent e,
                             Shape a,
                             ViewFactory f)
Forward the given DocumentEvent to the child views that need to be notified of the change to the model. If a child changed it's requirements and the allocation was valid prior to forwarding the portion of the box from the starting child to the end of the box will be repainted.
Overrides:
forwardUpdate in class View
Parameters:
ec - changes to the element this view is responsible for (may be null if there were no changes).
e - the change information from the associated document
a - the current allocation of the view
f - the factory to use to rebuild if the view has children
See Also:
View.insertUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory), View.removeUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory), View.changedUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

preferenceChanged

public void preferenceChanged(View child,
                              boolean width,
                              boolean height)
This is called by a child to indicated its preferred span has changed. This is implemented to throw away cached layout information so that new calculations will be done the next time the children need an allocation.
Overrides:
preferenceChanged in class View
Parameters:
child - the child view
width - true if the width preference should change
height - true if the height preference should change

getResizeWeight

public int getResizeWeight(int axis)
Gets the resize weight. A value of 0 or less is not resizable.
Overrides:
getResizeWeight in class View
Parameters:
axis - may be either View.X_AXIS or View.Y_AXIS
Returns:
the weight
Throws:
IllegalArgumentException - for an invalid axis

setSize

public void setSize(float width,
                    float height)
Sets the size of the view. If the size has changed, layout is redone. The size is the full size of the view including the inset areas.
Overrides:
setSize in class View
Parameters:
width - the width >= 0
height - the height >= 0

paint

public void paint(Graphics g,
                  Shape allocation)
Renders using the given rendering surface and area on that surface. Only the children that intersect the clip bounds of the given Graphics will be rendered.
Overrides:
paint in class View
Parameters:
g - the rendering surface to use
allocation - the allocated region to render into
See Also:
View.paint(java.awt.Graphics, java.awt.Shape)

getChildAllocation

public Shape getChildAllocation(int index,
                                Shape a)
Fetches the allocation for the given child view. This enables finding out where various views are located. This is implemented to return null if the layout is invalid, otherwise the superclass behavior is executed.
Overrides:
getChildAllocation in class CompositeView
Parameters:
index - the index of the child, >= 0 && < getViewCount()
a - the allocation to this view.
Returns:
the allocation to the child

modelToView

public Shape modelToView(int pos,
                         Shape a,
                         Position.Bias b)
                  throws BadLocationException
Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it. This makes sure the allocation is valid before letting the superclass do its thing.
Overrides:
modelToView in class CompositeView
Parameters:
pos - the position to convert >= 0
a - the allocated region to render into
Returns:
the bounding box of the given position
Throws:
BadLocationException - if the given position does not represent a valid location in the associated document
See Also:
View.modelToView(int, java.awt.Shape, javax.swing.text.Position.Bias)

viewToModel

public int viewToModel(float x,
                       float y,
                       Shape a,
                       Position.Bias[] bias)
Provides a mapping from the view coordinate space to the logical coordinate space of the model.
Overrides:
viewToModel in class CompositeView
Parameters:
x - x coordinate of the view location to convert >= 0
y - y coordinate of the view location to convert >= 0
a - the allocated region to render into
Returns:
the location within the model that best represents the given point in the view >= 0
See Also:
View.viewToModel(float, float, java.awt.Shape, javax.swing.text.Position.Bias[])

getAlignment

public float getAlignment(int axis)
Determines the desired alignment for this view along an axis. This is implemented to give the total alignment needed to position the children with the alignment points lined up along the axis orthoginal to the axis that is being tiled. The axis being tiled will request to be centered (i.e. 0.5f).
Overrides:
getAlignment in class View
Parameters:
axis - may be either View.X_AXIS or View.Y_AXIS
Throws:
IllegalArgumentException - for an invalid axis

getPreferredSpan

public float getPreferredSpan(int axis)
Determines the preferred span for this view along an axis.
Overrides:
getPreferredSpan in class View
Parameters:
axis - may be either View.X_AXIS or View.Y_AXIS
Throws:
IllegalArgumentException - for an invalid axis type

getMinimumSpan

public float getMinimumSpan(int axis)
Determines the minimum span for this view along an axis.
Overrides:
getMinimumSpan in class View
Parameters:
axis - may be either View.X_AXIS or View.Y_AXIS
Throws:
IllegalArgumentException - for an invalid axis type

getMaximumSpan

public float getMaximumSpan(int axis)
Determines the maximum span for this view along an axis.
Overrides:
getMaximumSpan in class View
Parameters:
axis - may be either View.X_AXIS or View.Y_AXIS
Throws:
IllegalArgumentException - for an invalid axis type

isAllocationValid

protected boolean isAllocationValid()
Are the allocations for the children still valid?
Returns:
true if allocations still valid

isBefore

protected boolean isBefore(int x,
                           int y,
                           Rectangle innerAlloc)
Determines if a point falls before an allocated region.
Overrides:
isBefore in class CompositeView
Parameters:
x - the X coordinate >= 0
y - the Y coordinate >= 0
innerAlloc - the allocated region. This is the area inside of the insets.
Returns:
true if the point lies before the region else false

isAfter

protected boolean isAfter(int x,
                          int y,
                          Rectangle innerAlloc)
Determines if a point falls after an allocated region.
Overrides:
isAfter in class CompositeView
Parameters:
x - the X coordinate >= 0
y - the Y coordinate >= 0
innerAlloc - the allocated region. This is the area inside of the insets.
Returns:
true if the point lies after the region else false

getViewAtPoint

protected View getViewAtPoint(int x,
                              int y,
                              Rectangle alloc)
Fetches the child view at the given point.
Overrides:
getViewAtPoint in class CompositeView
Parameters:
x - the X coordinate >= 0
y - the Y coordinate >= 0
alloc - the parents inner allocation on entry, which should be changed to the childs allocation on exit.
Returns:
the view

childAllocation

protected void childAllocation(int index,
                               Rectangle alloc)
Allocates a region for a child view.
Overrides:
childAllocation in class CompositeView
Parameters:
index - the index of the child view to allocate, >= 0 && < getViewCount()
alloc - the allocated region

layout

protected void layout(int width,
                      int height)
Performs layout of the children. The size is the area inside of the insets. This method calls the methods layoutMajorAxis and layoutMinorAxis as needed. To change how layout is done those methods should be reimplemented.
Parameters:
width - the width >= 0
height - the height >= 0

getWidth

public int getWidth()
The current width of the box. This is the width that it was last allocated.

getHeight

public int getHeight()
The current height of the box. This is the height that it was last allocated.

layoutMajorAxis

protected void layoutMajorAxis(int targetSpan,
                               int axis,
                               int[] offsets,
                               int[] spans)
Perform layout for the major axis of the box (i.e. the axis that it represents). The results of the layout should be placed in the given arrays which represent the allocations to the children along the major axis.
Parameters:
targetSpan - the total span given to the view, which whould be used to layout the children.
axis - the axis being layed out.
offsets - the offsets from the origin of the view for each of the child views. This is a return value and is filled in by the implementation of this method.
spans - the span of each child view. This is a return value and is filled in by the implementation of this method.

layoutMinorAxis

protected void layoutMinorAxis(int targetSpan,
                               int axis,
                               int[] offsets,
                               int[] spans)
Perform layout for the minor axis of the box (i.e. the axis orthoginal to the axis that it represents). The results of the layout should be placed in the given arrays which represent the allocations to the children along the minor axis.
Parameters:
targetSpan - the total span given to the view, which whould be used to layout the children.
axis - the axis being layed out.
offsets - the offsets from the origin of the view for each of the child views. This is a return value and is filled in by the implementation of this method.
spans - the span of each child view. This is a return value and is filled in by the implementation of this method.

calculateMajorAxisRequirements

protected SizeRequirements calculateMajorAxisRequirements(int axis,
                                                          SizeRequirements r)

calculateMinorAxisRequirements

protected SizeRequirements calculateMinorAxisRequirements(int axis,
                                                          SizeRequirements r)

baselineLayout

protected void baselineLayout(int targetSpan,
                              int axis,
                              int[] offsets,
                              int[] spans)

baselineRequirements

protected SizeRequirements baselineRequirements(int axis,
                                                SizeRequirements r)

getOffset

protected int getOffset(int axis,
                        int childIndex)
Fetch the offset of a particular childs current layout

getSpan

protected int getSpan(int axis,
                      int childIndex)
Fetch the span of a particular childs current layout

flipEastAndWestAtEnds

protected boolean flipEastAndWestAtEnds(int position,
                                        Position.Bias bias)
Description copied from class: CompositeView
Subclasses may wish to subclass this and conditionally return true based on the position. A return value of true indicates that when a View returns -1 from getNextVisualPositionFrom the next view for east should be the current index offset by -1, and for west it means offset by 1. The normal direction (for left to right text) is to offset east by 1 and west by -1.
Overrides:
flipEastAndWestAtEnds in class CompositeView
Following copied from class: javax.swing.text.CompositeView
Returns:
false

JavaTM 2 Platform
Std. Ed. v1.3.1

Submit a bug or feature
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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