javax.swing.text
class CompositeView

java.lang.Object javax.swing.text.View javax.swing.text.CompositeView

All Implemented Interfaces:

SwingConstants

Direct Known Subclasses:

BoxView

public abstract class CompositeView
extends View

CompositeView is an abstract View implementation which manages one or more child views. (Note that CompositeView is intended for managing relatively small numbers of child views.) CompositeView is intended to be used as a starting point for View implementations, such as BoxView, that will contain child Views. Subclasses that wish to manage the collection of child Views should use the {@link #replace} method. As View invokes replace during DocumentListener notification, you normally won't need to directly invoke replace.

While CompositeView does not impose a layout policy on its child Views, it does allow for inseting the child Views it will contain. The insets can be set by either {@link #setInsets} or {@link #setParagraphInsets}.

In addition to the abstract methods of {@link javax.swing.text.View}, subclasses of CompositeView will need to override:

• {@link #isBefore} - Used to test if a given View location is before the visual space of the CompositeView.
• {@link #isAfter} - Used to test if a given View location is after the visual space of the CompositeView.
• {@link #getViewAtPoint} - Returns the view at a given visual location.
• {@link #childAllocation} - Returns the bounds of a particular child View. getChildAllocation will invoke childAllocation after offseting the bounds by the Insets of the CompositeView.

CompositeView

public CompositeView(Element elem)

Constructs a CompositeView for the given element.

Parameters:

elem - the element this view is responsible for

childAllocation

protected abstract void childAllocation(int index,
                                        Rectangle a)

Returns the allocation for a given child.

Parameters:

index - the index of the child, >= 0 && < getViewCount()

a - the allocation to the interior of the box on entry, and the allocation of the child view at the index on exit.

flipEastAndWestAtEnds

protected boolean flipEastAndWestAtEnds(int position,
                                        Position.Bias bias)

Determines in which direction the next view lays. Consider the View at index n. Typically the Views are layed out from left to right, so that the View to the EAST will be at index n + 1, and the View to the WEST will be at index n - 1. In certain situations, such as with bidirectional text, it is possible that the View to EAST is not at index n + 1, but rather at index n - 1, or that the View to the WEST is not at index n - 1, but index n + 1. In this case this method would return true, indicating the Views are layed out in descending order.

This unconditionally returns false, subclasses should override this method if there is the possibility for laying Views in descending order.

Parameters:

position - position into the model

bias - either Position.Bias.Forward or Position.Bias.Backward

Returns:

false

getBottomInset

protected short getBottomInset()

Gets the bottom inset.

Returns:

the inset >= 0

getChildAllocation

public Shape getChildAllocation(int index,
                                Shape a)

Fetches the allocation for the given child view to render into. This enables finding out where various views are located.

Overrides:

getChildAllocation in class View

Parameters:

index - the index of the child, >= 0 && < getViewCount()

a - the allocation to this view

Returns:

the allocation to the child

getInsideAllocation

protected Rectangle getInsideAllocation(Shape a)

Translates the immutable allocation given to the view to a mutable allocation that represents the interior allocation (i.e. the bounds of the given allocation with the top, left, bottom, and right insets removed. It is expected that the returned value would be further mutated to represent an allocation to a child view. This is implemented to reuse an instance variable so it avoids creating excessive Rectangles. Typically the result of calling this method would be fed to the childAllocation method.

Parameters:

a - the allocation given to the view

Returns:

the allocation that represents the inside of the view after the margins have all been removed; if the given allocation was null, the return value is null

getLeftInset

protected short getLeftInset()

Gets the left inset.

Returns:

the inset >= 0

getNextEastWestVisualPositionFrom

protected int getNextEastWestVisualPositionFrom(int pos,
                                                Position.Bias b,
                                                Shape a,
                                                int direction,
                                                Position.Bias[] biasRet)
                                         throws BadLocationException

Returns the next visual position for the cursor, in either the east or west direction.

Parameters:

pos - the position to convert >= 0

b - a bias value of either Position.Bias.Forward or Position.Bias.Backward

a - the allocated region to render into

direction - the direction from the current position that can be thought of as the arrow keys typically found on a keyboard; this may be one of the following:

• SwingConstants.WEST
• SwingConstants.EAST

biasRet - an array containing the bias that was checked

Returns:

the location within the model that best represents the next west or east location

Throws:

BadLocationException

getNextNorthSouthVisualPositionFrom

protected int getNextNorthSouthVisualPositionFrom(int pos,
                                                  Position.Bias b,
                                                  Shape a,
                                                  int direction,
                                                  Position.Bias[] biasRet)
                                           throws BadLocationException

Returns the next visual position for the cursor, in either the north or south direction.

Parameters:

pos - the position to convert >= 0

b - a bias value of either Position.Bias.Forward or Position.Bias.Backward

a - the allocated region to render into

direction - the direction from the current position that can be thought of as the arrow keys typically found on a keyboard; this may be one of the following:

• SwingConstants.NORTH
• SwingConstants.SOUTH

biasRet - an array containing the bias that was checked

Returns:

the location within the model that best represents the next north or south location

Throws:

BadLocationException

getNextVisualPositionFrom

public int getNextVisualPositionFrom(int pos,
                                     Position.Bias b,
                                     Shape a,
                                     int direction,
                                     Position.Bias[] biasRet)
                              throws BadLocationException

Provides a way to determine the next visually represented model location that one might place a caret. Some views may not be visible, they might not be in the same order found in the model, or they just might not allow access to some of the locations in the model. This is a convenience method for {@link #getNextNorthSouthVisualPositionFrom} and {@link #getNextEastWestVisualPositionFrom}.

Overrides:

getNextVisualPositionFrom in class View

Parameters:

pos - the position to convert >= 0

b - a bias value of either Position.Bias.Forward or Position.Bias.Backward

a - the allocated region to render into

direction - the direction from the current position that can be thought of as the arrow keys typically found on a keyboard; this may be one of the following:

• SwingConstants.WEST
• SwingConstants.EAST
• SwingConstants.NORTH
• SwingConstants.SOUTH

biasRet - an array containing the bias that was checked

Returns:

the location within the model that best represents the next location visual position

Throws:

BadLocationException

getRightInset

protected short getRightInset()

Gets the right inset.

Returns:

the inset >= 0

getTopInset

protected short getTopInset()

Gets the top inset.

Returns:

the inset >= 0

getView

public View getView(int n)

Returns the n-th view in this container.

Overrides:

getView in class View

Parameters:

n - the number of the desired view, >= 0 && < getViewCount()

Returns:

the view at index n

getViewAtPoint

protected abstract View getViewAtPoint(int x,
                                       int y,
                                       Rectangle alloc)

Fetches the child view at the given coordinates.

Parameters:

x - the X coordinate >= 0

y - the Y coordinate >= 0

alloc - the parent's allocation on entry, which should be changed to the child's allocation on exit

Returns:

the child view

getViewAtPosition

protected View getViewAtPosition(int pos,
                                 Rectangle a)

Fetches the child view that represents the given position in the model. This is implemented to fetch the view in the case where there is a child view for each child element.

Parameters:

pos - the position >= 0

a - the allocation to the interior of the box on entry, and the allocation of the view containing the position on exit

Returns:

the view representing the given position, or null if there isn't one

getViewCount

public int getViewCount()

Returns the number of child views of this view.

Overrides:

getViewCount in class View

Returns:

the number of views >= 0

getViewIndex

public int getViewIndex(int pos,
                        Position.Bias b)

Returns the child view index representing the given position in the model. This is implemented to call the getViewIndexByPosition method for backward compatibility.

Overrides:

getViewIndex in class View

Parameters:

pos - the position >= 0

b

Returns:

index of the view representing the given position, or -1 if no view represents that position

getViewIndexAtPosition

protected int getViewIndexAtPosition(int pos)

Fetches the child view index representing the given position in the model. This is implemented to fetch the view in the case where there is a child view for each child element.

Parameters:

pos - the position >= 0

Returns:

index of the view representing the given position, or -1 if no view represents that position

isAfter

protected abstract boolean isAfter(int x,
                                   int y,
                                   Rectangle alloc)

Tests whether a point lies after the rectangle range.

Parameters:

x - the X coordinate >= 0

y - the Y coordinate >= 0

alloc - the rectangle

Returns:

true if the point is after the specified range

isBefore

protected abstract boolean isBefore(int x,
                                    int y,
                                    Rectangle alloc)

Tests whether a point lies before the rectangle range.

Parameters:

x - the X coordinate >= 0

y - the Y coordinate >= 0

alloc - the rectangle

Returns:

true if the point is before the specified range

loadChildren

protected void loadChildren(ViewFactory f)

Loads all of the children to initialize the view. This is called by the {@link #setParent} method. Subclasses can reimplement this to initialize their child views in a different manner. The default implementation creates a child view for each child element.

Parameters:

f - the view factory

modelToView

public Shape modelToView(int p0,
                         Position.Bias b0,
                         int p1,
                         Position.Bias b1,
                         Shape a)
                  throws BadLocationException

Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.

Overrides:

modelToView in class View

Parameters:

p0 - the position to convert >= 0

b0 - the bias toward the previous character or the next character represented by p0, in case the position is a boundary of two views; either Position.Bias.Forward or Position.Bias.Backward

p1 - the position to convert >= 0

b1 - the bias toward the previous character or the next character represented by p1, in case the position is a boundary of two views

a - the allocated region to render into

Returns:

the bounding box of the given position is returned

Throws:

BadLocationException - if the given position does not represent a valid location in the associated document

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.

Overrides:

modelToView in class View

Parameters:

pos - the position to convert >= 0

a - the allocated region to render into

b - a bias value of either Position.Bias.Forward or Position.Bias.Backward

Returns:

the bounding box of the given position

Throws:

BadLocationException - if the given position does not represent a valid location in the associated document

replace

public void replace(int offset,
                    int length,
                    View[] views)

Replaces child views. If there are no views to remove this acts as an insert. If there are no views to add this acts as a remove. Views being removed will have the parent set to null, and the internal reference to them removed so that they may be garbage collected.

Overrides:

replace in class View

Parameters:

offset - the starting index into the child views to insert the new views; >= 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)

setInsets

protected void setInsets(short top,
                         short left,
                         short bottom,
                         short right)

Sets the insets for the view.

Parameters:

top - the top inset >= 0

left - the left inset >= 0

bottom - the bottom inset >= 0

right - the right inset >= 0

setParagraphInsets

protected void setParagraphInsets(AttributeSet attr)

Sets the insets from the paragraph attributes specified in the given attributes.

Parameters:

attr - the attributes

setParent

public void setParent(View parent)

Sets the parent of the view. This is reimplemented to provide the superclass behavior as well as calling the loadChildren method if this view does not already have children. The children should not be loaded in the constructor because the act of setting the parent may cause them to try to search up the hierarchy (to get the hosting Container for example). If this view has children (the view is being moved from one place in the view hierarchy to another), the loadChildren method will not be called.

Overrides:

setParent in class View

Parameters:

parent - the parent of the view, null if none

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 View

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

bias - either Position.Bias.Forward or Position.Bias.Backward

Returns:

the location within the model that best represents the given point in the view >= 0