A LabelView is a styled chunk of text that represents a view mapped over an element in the text model. It caches the character level attributes used for rendering.
@author
Timothy Prinzing
@version
1.68 06/28/04
Constructs a new view wrapped on an element.
Parameters
elemthe element
The weight to indicate a view is a bad break opportunity for the purpose of formatting. This value indicates that no attempt should be made to break the view into fragments as the view has not been written to support fragmenting.
The weight to indicate a view supports breaking, and this represents a very attractive place to break.
The weight to indicate a view supports breaking, and must be broken to be represented properly when placed in a view that formats its children by breaking them.
The weight to indicate a view supports breaking, but better opportunities probably exist.
Axis for format/break operations.
Axis for format/break operations.
Appends a single child view. This is a convenience call to replace.
Parameters
vthe view
@since
1.3
See Also
Breaks this view on the given axis at the given length. This is implemented to attempt to break on a whitespace location, and returns a fragment with the whitespace at the end. If a whitespace location can't be found, the nearest character is used.
Parameters
axismay be either View.X_AXIS or View.Y_AXIS
p0the location in the model where the fragment should start it's representation >= 0.
posthe position along the axis that the broken view would occupy >= 0. This may be useful for things like tab calculations.
lenspecifies the distance along the axis where a potential break is desired >= 0.
Return
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.
Gives notification from the document that attributes were changed in a location that this view is responsible for.
Parameters
ethe change information from the associated document
athe current allocation of the view
fthe factory to use to rebuild if the view has children
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.

This view does support fragmenting. It is implemented to return a nested class that shares state in this view representing only a portion of the view.

Parameters
p0the starting offset >= 0. This should be a value greater or equal to the element starting offset and less than the element ending offset.
p1the ending offset > p0. This should be a value less than or equal to the elements end offset and greater than the elements starting offset.
Return
the view fragment, or itself if the view doesn't support breaking into fragments
See Also
Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Parameters
objthe reference object with which to compare.
Return
true if this object is the same as the obj argument; false otherwise.
Determines the desired alignment for this view along an axis. For the label, the alignment is along the font baseline for the y axis, and the superclasses alignment along the x axis.
Parameters
axismay be either View.X_AXIS or View.Y_AXIS
Return
the desired alignment. This should be a value between 0.0 and 1.0 inclusive, where 0 indicates alignment at the origin and 1.0 indicates alignment to the full span away from the origin. An alignment of 0.5 would be the center of the view.
Fetches the attributes to use when rendering. By default this simply returns the attributes of the associated element. This method should be used rather than using the element directly to obtain access to the attributes to allow view-specific attributes to be mixed in or to allow the view to have view-specific conversion of attributes by subclasses. Each view should document what attributes it recognizes for the purpose of rendering or layout, and should always access them through the AttributeSet returned by this method.
Fetches the background color to use to render the glyphs. This is implemented to return a cached background color, which defaults to null.
Return
the cached background color
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. The higher the weight, the more attractive the break. A value equal to or lower than View.BadBreakWeight should not be considered for a break. A value greater than or equal to View.ForcedBreakWeight should be broken.

This is implemented to forward to the superclass for the Y_AXIS. Along the X_AXIS the following values may be returned.

View.ExcellentBreakWeight
if there is whitespace proceeding the desired break location.
View.BadBreakWeight
if the desired break location results in a break location of the starting offset.
View.GoodBreakWeight
if the other conditions don't occur.
This will normally result in the behavior of breaking on a whitespace location if one can be found, otherwise breaking between characters.
Parameters
axismay be either View.X_AXIS or View.Y_AXIS
posthe potential location of the start of the broken view >= 0. This may be useful for calculating tab positions.
lenspecifies the relative length from pos where a potential break is desired >= 0.
Return
the weight, which should be a value between View.ForcedBreakWeight and View.BadBreakWeight.
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.
Parameters
indexthe index of the child, >= 0 && < getViewCount()
athe allocation to this view
Return
the allocation to the child
Returns the runtime class of an object. That Class object is the object that is locked by static synchronized methods of the represented class.
Return
The java.lang.Class object that represents the runtime class of the object. The result is of type {@code Class} where X is the erasure of the static type of the expression on which getClass is called.
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.
Return
the container, null if none
Fetches the model associated with the view.
Return
the view model, null if none
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.
Return
the subject
Fetches the portion of the model that this view is responsible for.
Return
the ending offset into the model
Fetches the font that the glyphs should be based upon. This is implemented to return a cached font.
Return
the cached font
Fetches the foreground color to use to render the glyphs. This is implemented to return a cached foreground color, which defaults to null.
Return
the cached foreground color
Fetch the currently installed glyph painter. If a painter has not yet been installed, and a default was not yet needed, null is returned.
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.
Return
a Graphics object for rendering
@since
1.3
Determines the maximum span for this view along an axis.
Parameters
axismay be either View.X_AXIS or View.Y_AXIS
Return
the maximum span the view can be rendered into
Determines the minimum span for this view along an axis.
Parameters
axismay be either View.X_AXIS or View.Y_AXIS
Return
the minimum span the view can be rendered into
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.
Parameters
posthe position to convert >= 0
athe allocated region to render into
directionthe direction from the current position that can be thought of as the arrow keys typically found on a keyboard. This may be SwingConstants.WEST, SwingConstants.EAST, SwingConstants.NORTH, or SwingConstants.SOUTH.
Return
the location within the model that best represents the next location visual position.
Throws
BadLocationException
IllegalArgumentExceptionfor an invalid direction
Returns the parent of the view.
Return
the parent, or null if none exists
Determines the span along the same axis as tab expansion for a portion of the view. This is intended for use by the TabExpander for cases where the tab expansion involves aligning the portion of text that doesn't have whitespace relative to the tab stop. There is therefore an assumption that the range given does not contain tabs.

This method can be called while servicing the getTabbedSpan or getPreferredSize. It has to arrange for its own text buffer to make the measurements.

Parameters
p0the starting document offset >= 0
p1the ending document offset >= p0
Return
the span >= 0
Determines the preferred span for this view along an axis.
Parameters
axismay be either View.X_AXIS or View.Y_AXIS
Return
the span the view would like to be rendered into >= 0. Typically the view is told to render into the span that is returned, although there is no guarantee. The parent may choose to resize or break the view.
Determines the resizability of the view along the given axis. A value of 0 or less is not resizable.
Parameters
axismay be either View.X_AXIS or View.Y_AXIS
Return
the weight
Fetches the portion of the model that this view is responsible for.
Return
the starting offset into the model
Determines the desired span when using the given tab expansion implementation.
Parameters
xthe position the view would be located at for the purpose of tab expansion >= 0.
ehow to expand the tabs when encountered.
Return
the desired span >= 0
Fetch the TabExpander to use if tabs are present in this view.
Fetch a reference to the text that occupies the given range. This is normally used by the GlyphPainter to determine what characters it should render glyphs for.
Parameters
p0the starting document offset >= 0
p1the ending document offset >= p0
Return
the Segment containing the text
Returns the tooltip text at the specified location. The default implementation returns the value from the child View identified by the passed in location.
@since
1.4
Gets the nth child view. Since there are no children by default, this returns null.
Parameters
nthe number of the view to get, >= 0 && < getViewCount()
Return
the view
Returns the number of views in this view. Since the default is to not be a composite view this returns 0.
Return
the number of views >= 0
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.
Return
the factory, null if none
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.
Parameters
xthe x coordinate
ythe y coordinate
allocationcurrent allocation of the View.
Return
index of the view representing the given location, or -1 if no view represents that position
@since
1.4
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.
Parameters
posthe position >= 0
Return
index of the view representing the given position, or -1 if no view represents that position
@since
1.3
Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by java.util.Hashtable.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hashtables.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)

Return
a hash code value for this object.
Inserts a single child view. This is a convenience call to replace.
Parameters
offsthe offset of the view to insert before >= 0
vthe view
@since
1.3
See Also
Gives notification that something was inserted into the document in a location that this view is responsible for. This is implemented to call preferenceChanged along the axis the glyphs are rendered.
Parameters
ethe change information from the associated document
athe current allocation of the view
fthe factory to use to rebuild if the view has children
Determines if the glyphs should have a strikethrough line. If true, a line should be drawn through the center of the glyphs. This is implemented to return the cached strikeThrough property.

When you request this property, LabelView re-syncs its state with the properties of the Element's AttributeSet. If Element's AttributeSet does not have this property set, it will revert to false.

Return
the value of the cached strikeThrough property
Determines if the glyphs should be rendered as superscript.
Return
the value of the cached subscript property

When you request this property, LabelView re-syncs its state with the properties of the Element's AttributeSet. If Element's AttributeSet does not have this property set, it will revert to false.

the value of the cached subscript property
Determines if the glyphs should be rendered as subscript.

When you request this property, LabelView re-syncs its state with the properties of the Element's AttributeSet. If Element's AttributeSet does not have this property set, it will revert to false.

Return
the value of the cached superscript property
Determines if the glyphs should be underlined. If true, an underline should be drawn through the baseline. This is implemented to return the cached underline property.

When you request this property, LabelView re-syncs its state with the properties of the Element's AttributeSet. If Element's AttributeSet does not have this property set, it will revert to false.

Return
the value of the cached underline property
Returns a boolean that indicates whether the view is visible or not. By default all views are visible.
Return
always returns true
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.
Parameters
p0the position of the first character (>=0)
b0the 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
p1the position of the last character (>=0)
b1the bias for the second character position, defined one of the legal values shown above
athe area of the view, which encompasses the requested region
Return
the bounding box which is a union of the region specified by the first and last character positions
Throws
BadLocationExceptionif the given position does not represent a valid location in the associated document
IllegalArgumentExceptionif b0 or b1 are not one of the legal Position.Bias values listed above
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.
Parameters
posthe position to convert >= 0
athe allocated region in which to render
Return
the bounding box of the given position is returned
Throws
BadLocationExceptionif the given position does not represent a valid location in the associated document
@deprecated
Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.
Parameters
posthe position to convert >= 0
athe allocated region to render into
beither Position.Bias.Forward or Position.Bias.Backward
Return
the bounding box of the given position
Throws
BadLocationExceptionif the given position does not represent a valid location in the associated document
Wakes up a single thread that is waiting on this object's monitor. If any threads are waiting on this object, one of them is chosen to be awakened. The choice is arbitrary and occurs at the discretion of the implementation. A thread waits on an object's monitor by calling one of the wait methods.

The awakened thread will not be able to proceed until the current thread relinquishes the lock on this object. The awakened thread will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened thread enjoys no reliable privilege or disadvantage in being the next thread to lock this object.

This method should only be called by a thread that is the owner of this object's monitor. A thread becomes the owner of the object's monitor in one of three ways:

  • By executing a synchronized instance method of that object.
  • By executing the body of a synchronized statement that synchronizes on the object.
  • For objects of type Class, by executing a synchronized static method of that class.

Only one thread at a time can own an object's monitor.

Throws
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
Wakes up all threads that are waiting on this object's monitor. A thread waits on an object's monitor by calling one of the wait methods.

The awakened threads will not be able to proceed until the current thread relinquishes the lock on this object. The awakened threads will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened threads enjoy no reliable privilege or disadvantage in being the next thread to lock this object.

This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.

Throws
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
Renders a portion of a text style run.
Parameters
gthe rendering surface to use
athe allocated region to render into
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
childthe child view
widthtrue if the width preference has changed
heighttrue if the height preference has changed
Removes one of the children at the given position. This is a convenience call to replace.
@since
1.3
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. This is implemented to call preferenceChanged along the axis the glyphs are rendered.
Parameters
ethe change information from the associated document
athe current allocation of the view
fthe factory to use to rebuild if the view has children
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
offsetthe starting index into the child views to insert the new views. This should be a value >= 0 and <= getViewCount
lengththe number of existing child views to remove This should be a value >= 0 and <= (getViewCount() - offset).
viewsthe child views to add. This value can be null to indicate no children are being added (useful to remove).
@since
1.3
Sets the painter to use for rendering glyphs.
Establishes the parent view for this view. This is guaranteed to be called before any other methods if the parent view is functioning properly. This is also the last method called, since it is called to indicate the view has been removed from the hierarchy as well. When this method is called to set the parent to null, this method does the same for each of its children, propogating the notification that they have been disconnected from the view tree. If this is reimplemented, super.setParent() should be called.
Parameters
parentthe new parent, or null if the view is being removed from a parent
Sets the size of the view. This should cause layout of the view along the given axis, if it has any layout duties.
Parameters
widththe width >= 0
heightthe height >= 0
Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 
Return
a string representation of the object.
Provides a mapping from the view coordinate space to the logical coordinate space of the model.
Parameters
xthe X coordinate >= 0
ythe Y coordinate >= 0
athe allocated region in which to render
Return
the location within the model that best represents the given point in the view >= 0
@deprecated
Provides a mapping from the view coordinate space to the logical coordinate space of the model.
Parameters
xthe X coordinate >= 0
ythe Y coordinate >= 0
athe allocated region to render into
biasReturneither Position.Bias.Forward or Position.Bias.Backward is returned as the zero-th element of this array
Return
the location within the model that best represents the given point of view >= 0
Causes current thread to wait until another thread invokes the method or the method for this object. In other words, this method behaves exactly as if it simply performs the call wait(0).

The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until another thread notifies threads waiting on this object's monitor to wake up either through a call to the notify method or the notifyAll method. The thread then waits until it can re-obtain ownership of the monitor and resumes execution.

As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait();
         ... // Perform action appropriate to condition
     }
 
This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.
Throws
IllegalMonitorStateExceptionif the current thread is not the owner of the object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.
Causes current thread to wait until either another thread invokes the method or the method for this object, or a specified amount of time has elapsed.

The current thread must own this object's monitor.

This method causes the current thread (call it T) to place itself in the wait set for this object and then to relinquish any and all synchronization claims on this object. Thread T becomes disabled for thread scheduling purposes and lies dormant until one of four things happens:

  • Some other thread invokes the notify method for this object and thread T happens to be arbitrarily chosen as the thread to be awakened.
  • Some other thread invokes the notifyAll method for this object.
  • Some other thread interrupts thread T.
  • The specified amount of real time has elapsed, more or less. If timeout is zero, however, then real time is not taken into consideration and the thread simply waits until notified.
The thread T is then removed from the wait set for this object and re-enabled for thread scheduling. It then competes in the usual manner with other threads for the right to synchronize on the object; once it has gained control of the object, all its synchronization claims on the object are restored to the status quo ante - that is, to the situation as of the time that the wait method was invoked. Thread T then returns from the invocation of the wait method. Thus, on return from the wait method, the synchronization state of the object and of thread T is exactly as it was when the wait method was invoked.

A thread can also wake up without being notified, interrupted, or timing out, a so-called spurious wakeup. While this will rarely occur in practice, applications must guard against it by testing for the condition that should have caused the thread to be awakened, and continuing to wait if the condition is not satisfied. In other words, waits should always occur in loops, like this one:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait(timeout);
         ... // Perform action appropriate to condition
     }
 
(For more information on this topic, see Section 3.2.3 in Doug Lea's "Concurrent Programming in Java (Second Edition)" (Addison-Wesley, 2000), or Item 50 in Joshua Bloch's "Effective Java Programming Language Guide" (Addison-Wesley, 2001).

If the current thread is interrupted by another thread while it is waiting, then an InterruptedException is thrown. This exception is not thrown until the lock status of this object has been restored as described above.

Note that the wait method, as it places the current thread into the wait set for this object, unlocks only this object; any other objects on which the current thread may be synchronized remain locked while the thread waits.

This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.

Parameters
timeoutthe maximum time to wait in milliseconds.
Throws
IllegalArgumentExceptionif the value of timeout is negative.
IllegalMonitorStateExceptionif the current thread is not the owner of the object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.
Causes current thread to wait until another thread invokes the method or the method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.

This method is similar to the wait method of one argument, but it allows finer control over the amount of time to wait for a notification before giving up. The amount of real time, measured in nanoseconds, is given by:

 1000000*timeout+nanos

In all other respects, this method does the same thing as the method of one argument. In particular, wait(0, 0) means the same thing as wait(0).

The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until either of the following two conditions has occurred:

  • Another thread notifies threads waiting on this object's monitor to wake up either through a call to the notify method or the notifyAll method.
  • The timeout period, specified by timeout milliseconds plus nanos nanoseconds arguments, has elapsed.

The thread then waits until it can re-obtain ownership of the monitor and resumes execution.

As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait(timeout, nanos);
         ... // Perform action appropriate to condition
     }
 
This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.
Parameters
timeoutthe maximum time to wait in milliseconds.
nanosadditional time, in nanoseconds range 0-999999.
Throws
IllegalArgumentExceptionif the value of timeout is negative or the value of nanos is not in the range 0-999999.
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.