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.
Constructs a new view wrapped on an 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
.
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.
Gives notification from the document that attributes were changed
in a location that this view is responsible for.
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.
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.
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.
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
.
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.
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 runtime class of an object. That Class
object is the object that is locked by static synchronized
methods of the represented class.
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.
Fetches the model associated with the view.
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.
Fetches the portion of the model that this view is responsible for.
Fetches the font that the glyphs should be based upon.
This is implemented to return a 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
.
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.
Determines the maximum span for this view along an
axis.
Determines the minimum span for this view along an
axis.
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.
Returns the parent of the view.
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.
Determines the preferred span for this view along an
axis.
Determines the resizability of the view along the
given axis. A value of 0 or less is not resizable.
Fetches the portion of the model that this view is responsible for.
Determines the desired span when using the given
tab expansion implementation.
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.
Returns the tooltip text at the specified location. The default
implementation returns the value from the child View identified by
the passed in location.
Gets the nth child view. Since there are no
children by default, this returns null
.
Returns the number of views in this view. Since
the default is to not be a composite view this
returns 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.
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 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 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.)
Inserts a single child view. This is a convenience
call to replace
.
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.
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.
Determines if the glyphs should be rendered as superscript.
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.
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.
Returns a boolean that indicates whether
the view is visible or not. By default
all views are visible.
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.
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.
Provides a mapping from the document model coordinate space
to the coordinate space of the view mapped to it.
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.
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.
Renders a portion of a text style run.
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.
Removes one of the children at the given position.
This is a convenience call to replace
.
Removes all of the children. This is a convenience
call to replace
.
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.
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.
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.
Sets the size of the view. This should cause
layout of the view along the given axis, if it
has any layout duties.
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())
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.
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.
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.
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.