Appends a single child view.

  Appends a single child view. This is a convenience
call to replace.
Parameters:
- v - the view
Since: 1.3
See Also: View.replace(int, int, javax.swing.text.View[]),

  Tries to break this view on the given axis.

  Tries to break this view on the given axis. This is called by views that try to do formatting of their children. For example, a view of a paragraph will typically try to place its children into row and views representing chunks of text can sometimes be broken down into smaller pieces.

This is implemented to return the view itself, which represents the default behavior on not being breakable. If the view does support breaking, the starting offset of the view returned should be the given offset, and the end offset should be less than or equal to the end offset of the view being broken.
Returns: the fragment of the view that represents the given span, if the view can be broken. If the view doesn't support breaking behavior, the view itself is returned.
Parameters:
- axis - may be either View.X_AXIS or View.Y_AXIS
- offset - the location in the document model that a broken fragment would occupy >= 0. This would be the starting offset of the fragment returned
- pos - the position along the axis that the broken view would occupy >= 0. This may be useful for things like tab calculations
- len - specifies the distance along the axis where a potential break is desired >= 0
See Also: ParagraphView,

  Creates a view that represents a portion of the element.

  Creates a view that represents a portion of the element.
This is potentially useful during formatting operations
for taking measurements of fragments of the view. If
the view doesn't support fragmenting (the default), it
should return itself.
Returns: the view fragment, or itself if the view doesn't support breaking into fragments
Parameters:
- p0 - the starting offset >= 0. This should be a value greater or equal to the element starting offset and less than the element ending offset.
- p1 - the ending offset > p0. This should be a value less than or equal to the elements end offset and greater than the elements starting offset.
See Also: LabelView,

  Forwards the given DocumentEvent to the child views that need to be notified of the change to the model.

  Forwards the given DocumentEvent to the child views
that need to be notified of the change to the model.
If there were changes to the element this view is
responsible for, that should be considered when
forwarding (i.e. new child views should not get
notified).
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
Since: 1.3
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),

  Forwards the DocumentEvent to the give child view.

  Forwards the DocumentEvent to the give child view. This
simply messages the view with a call to insertUpdate,
removeUpdate, or changedUpdate depending
upon the type of the event. This is called by
forwardUpdate to forward
the event to children that need it.
Parameters:
- v - the child view to forward the event to
- 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
Since: 1.3
See Also: View.forwardUpdate(javax.swing.event.DocumentEvent.ElementChange, javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory),

  Determines how attractive a break opportunity in this view is.

  Determines how attractive a break opportunity in this view is. This can be used for determining which view is the most attractive to call breakView on in the process of formatting. A view that represents text that has whitespace in it might be more attractive than a view that has no whitespace, for example. The higher the weight, the more attractive the break. A value equal to or lower than BadBreakWeight should not be considered for a break. A value greater than or equal to ForcedBreakWeight should be broken.

This is implemented to provide the default behavior of returning BadBreakWeight unless the length is greater than the length of the view in which case the entire view represents the fragment. Unless a view has been written to support breaking behavior, it is not attractive to try and break the view. An example of a view that does support breaking is LabelView. An example of a view that uses break weight is ParagraphView.
Returns: the weight, which should be a value between ForcedBreakWeight and BadBreakWeight
Parameters:
- axis - may be either View.X_AXIS or View.Y_AXIS
- pos - the potential location of the start of the broken view >= 0. This may be useful for calculating tab positions
- len - specifies the relative length from pos where a potential break is desired >= 0
See Also: LabelView, ParagraphView, View.BadBreakWeight, View.GoodBreakWeight, View.ExcellentBreakWeight, View.ForcedBreakWeight,

  Fetches the allocation for the given child view.

  Fetches the allocation for the given child view.
This enables finding out where various views
are located, without assuming how the views store
their location. This returns null since the
default is to not have any child views.
Returns: the allocation to the child
Parameters:
- index - the index of the child, >= 0 && < getViewCount()
- a - the allocation to this view

  Fetches the container hosting the view.

  Fetches the container hosting the view. This is useful for
things like scheduling a repaint, finding out the host
components font, etc. The default implementation
of this is to forward the query to the parent view.
Returns: the container, null if none

  Fetches the model associated with the view.

  Fetches the model associated with the view.
Returns: the view model, null if none
See Also: View.getDocument(),

  Fetches the structural portion of the subject that this view is mapped to.

  Fetches the structural portion of the subject that this
view is mapped to. The view may not be responsible for the
entire portion of the element.
Returns: the subject
See Also: View.getElement(),

  Fetches the portion of the model for which this view is responsible.

  Fetches the portion of the model for which this view is
responsible.
Returns: the ending offset into the model >= 0
See Also: View.getEndOffset(),

  Fetch a Graphics for rendering.

  Fetch a Graphics for rendering.
This can be used to determine
font characteristics, and will be different for a print view
than a component view.
Returns: a Graphics object for rendering
Since: 1.3

  Determines the maximum span for this view along an axis.

  Determines the maximum span for this view along an
axis.
Returns: the maximum span the view can be rendered into
Parameters:
- axis - may be either View.X_AXIS or View.Y_AXIS
See Also: View.getPreferredSpan(int),

  Determines the minimum span for this view along an axis.

  Determines the minimum span for this view along an
axis.
Returns: the minimum span the view can be rendered into
Parameters:
- axis - may be either View.X_AXIS or View.Y_AXIS
See Also: View.getPreferredSpan(int),

  Provides a way to determine the next visually represented model location at which one might place a caret.

  Provides a way to determine the next visually represented model
location at which 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.
Returns: the location within the model that best represents the next location visual position
Parameters:
- pos - the position to convert >= 0
- a - the allocated region in which to render
- direction - the direction from the current position that can be thought of as the arrow keys typically found on a keyboard. This will be one of the following values:

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

Throws:
- BadLocationException -
- IllegalArgumentException - if direction doesn't have one of the legal values above

  Returns the parent of the view.

  Returns the parent of the view.
Returns: the parent, or null if none exists

  Determines the resizability of the view along the given axis.

  Determines the resizability of the view along the
given axis. A value of 0 or less is not resizable.
Returns: the weight
Parameters:
- axis - may be either View.X_AXIS or View.Y_AXIS

  Fetches the portion of the model for which this view is responsible.

  Fetches the portion of the model for which this view is
responsible.
Returns: the starting offset into the model >= 0
See Also: View.getStartOffset(),

  Gets the nth child view.

  Gets the nth child view. Since there are no
children by default, this returns null.
Returns: the view
Parameters:
- n - the number of the view to get, >= 0 && < getViewCount()

  Returns the number of views in this view.

  Returns the number of views in this view. Since
the default is to not be a composite view this
returns 0.
Returns: the number of views >= 0
See Also: View.getViewCount(),

  Fetches the ViewFactory implementation that is feeding the view hierarchy.

  Fetches the ViewFactory implementation that is feeding
the view hierarchy. Normally the views are given this
as an argument to updates from the model when they
are most likely to need the factory, but this
method serves to provide it at other times.
Returns: the factory, null if none

  Returns the child view index representing the given position in the view.

  Returns the child view index representing the given position in
the view. This iterates over all the children returning the
first with a bounds that contains x, y.
Returns: index of the view representing the given location, or -1 if no view represents that position
Parameters:
- x - the x coordinate
- y - the y coordinate
- allocation - current allocation of the View.
Since: 1.4

  Returns the child view index representing the given position in the model.

  Returns the child view index representing the given position in
the model. By default a view has no children so this is implemented
to return -1 to indicate there is no valid child index for any
position.
Returns: index of the view representing the given position, or -1 if no view represents that position
Parameters:
- pos - the position >= 0
Since: 1.3

  Inserts a single child view.

  Inserts a single child view. This is a convenience
call to replace.
Parameters:
- offs - the offset of the view to insert before >= 0
- v - the view
Since: 1.3
See Also: View.replace(int, int, javax.swing.text.View[]),

  Gives notification that something was inserted into the document in a location that this view is responsible for.

  Gives notification that something was inserted into
the document in a location that this view is responsible for.
To reduce the burden to subclasses, this functionality is
spread out into the following calls that subclasses can
reimplement:

1. updateChildren is called
   if there were any changes to the element this view is
   responsible for. If this view has child views that are
   represent the child elements, then this method should do
   whatever is necessary to make sure the child views correctly
   represent the model.
   
2. forwardUpdate is called
   to forward the DocumentEvent to the appropriate child views.
   
3. updateLayout is called to
   give the view a chance to either repair its layout, to reschedule
   layout, or do nothing.
   

Parameters:
- 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),

  Returns a boolean that indicates whether the view is visible or not.

  Returns a boolean that indicates whether
the view is visible or not. By default
all views are visible.
Returns: always returns true

  Provides a mapping, for a given region, from the document model coordinate space to the view coordinate space.

  Provides a mapping, for a given region,
from the document model coordinate space
to the view coordinate space. The specified region is
created as a union of the first and last character positions.
Returns: the bounding box which is a union of the region specified by the first and last character positions
Parameters:
- p0 - the position of the first character (>=0)
- b0 - the bias of the first character position, toward the previous character or the next character represented by the offset, in case the position is a boundary of two views; b0 will have one of these values:

• Position.Bias.Forward
• Position.Bias.Backward

- p1 - the position of the last character (>=0)
- b1 - the bias for the second character position, defined one of the legal values shown above
- a - the area of the view, which encompasses the requested region
Throws:
- BadLocationException - if the given position does not represent a valid location in the associated document
- IllegalArgumentException - if b0 or b1 are not one of the legal Position.Bias values listed above
See Also: View.viewToModel(float, float, java.awt.Shape, javax.swing.text.Position.Bias[]),

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

  Provides a mapping from the document model coordinate space
to the coordinate space of the view mapped to it. This is
implemented to default the bias to Position.Bias.Forward
which was previously implied.
Returns: the bounding box of the given position is returned
Parameters:
- pos - the position to convert >= 0
- a - the allocated region in which to render
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),

  Child views can call this on the parent to indicate that the preference has changed and should be reconsidered for layout.

  Child views can call this on the parent to indicate that
the preference has changed and should be reconsidered
for layout. By default this just propagates upward to
the next parent. The root view will call
revalidate on the associated text component.
Parameters:
- child - the child view
- width - true if the width preference has changed
- height - true if the height preference has changed
See Also: JComponent.revalidate(),

  Removes one of the children at the given position.

  Removes one of the children at the given position.
This is a convenience call to replace.
Since: 1.3

  Removes all of the children.

  Removes all of the children. This is a convenience
call to replace.
Since: 1.3

  Gives notification that something was removed from the document in a location that this view is responsible for.

  Gives notification that something was removed from the document
in a location that this view is responsible for.
To reduce the burden to subclasses, this functionality is
spread out into the following calls that subclasses can
reimplement:

1. updateChildren is called
   if there were any changes to the element this view is
   responsible for. If this view has child views that are
   represent the child elements, then this method should do
   whatever is necessary to make sure the child views correctly
   represent the model.
   
2. forwardUpdate is called
   to forward the DocumentEvent to the appropriate child views.
   
3. updateLayout is called to
   give the view a chance to either repair its layout, to reschedule
   layout, or do nothing.
   

Parameters:
- 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.removeUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory),

  Replaces child 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 can be garbage collected.
This is implemented to do nothing, because by default
a view has no children.
Parameters:
- offset - 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).
Since: 1.3

  Updates the child views in response to receiving notification that the model changed, and there is change record for the element this view is responsible for.

  Updates the child views in response to receiving notification
that the model changed, and there is change record for the
element this view is responsible for. This is implemented
to assume the child views are directly responsible for the
child elements of the element this view represents. The
ViewFactory is used to create child views for each element
specified as added in the ElementChange, starting at the
index specified in the given ElementChange. The number of
child views representing the removed elements specified are
removed.
Returns: whether or not the child views represent the child elements of the element this view is responsible for. Some views create children that represent a portion of the element they are responsible for, and should return false. This information is used to determine if views in the range of the added elements should be forwarded to or not
Parameters:
- ec - the change information for the element this view is responsible for. This should not be null if this method gets called
- e - the change information from the associated document
- f - the factory to use to build child views
Since: 1.3
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),

  Updates the layout in response to receiving notification of change from the model.

  Updates the layout in response to receiving notification of
change from the model. This is implemented to call
preferenceChanged to reschedule a new layout
if the ElementChange record is not null.
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
Since: 1.3
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),

  Provides a mapping from the view coordinate space to the logical coordinate space of the model.

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