TextHitInfo class represents a character position in a
text model, and a bias, or "side," of the character. Biases are
either leading (the left edge, for a left-to-right character)
or trailing (the right edge, for a left-to-right character).
Instances of TextHitInfo are used to specify caret and
insertion positions within text.
For example, consider the text "abc". TextHitInfo.trailing(1) corresponds to the right side of the 'b' in the text.
TextHitInfo is used primarily by TextLayout
and
clients of TextLayout. Clients of TextLayout
query TextHitInfo instances for an insertion offset, where
new text is inserted into the text model. The insertion offset is equal
to the character position in the TextHitInfo if the bias
is leading, and one character after if the bias is trailing. The
insertion offset for TextHitInfo.trailing(1) is 2.
Sometimes it is convenient to construct a TextHitInfo with
the same insertion offset as an existing one, but on the opposite
character. The getOtherHit method constructs a new
TextHitInfo with the same insertion offset as an existing
one, with a hit on the character on the other side of the insertion offset.
Calling getOtherHit on trailing(1) would return leading(2).
In general, getOtherHit for trailing(n) returns
leading(n+1) and getOtherHit for leading(n)
returns trailing(n-1).
Example:
Converting a graphical point to an insertion point within a text model
TextLayout layout = ...; Point2D.Float hitPoint = ...; TextHitInfo hitInfo = layout.hitTestChar(hitPoint.x, hitPoint.y); int insPoint = hitInfo.getInsertionIndex(); // insPoint is relative to layout; may need to adjust for use // in a text model
TextHitInfo at the specified offset,
associated with the character after the offset.TextHitInfo at the specified offset,
associated with the character before the offset.true if the specified Object is a
TextHitInfo and equals this TextHitInfo.true if the specified TextHitInfo
has the same charIndex and isLeadingEdge
as this TextHitInfo. This is not the same as having
the same insertion offset.TextHitInfo whose character index is offset
by delta from the charIndex of this
TextHitInfo. This TextHitInfo remains
unchanged.TextHitInfo on the other side of the
insertion point. This TextHitInfo remains unchanged.true if the leading edge of the character was
hit.TextHitInfo on the leading edge of the
character at the specified charIndex.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:
synchronized statement
that synchronizes on the object.
Class, by executing a
synchronized static method of that class.
Only one thread at a time can own an object's monitor.
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.
String representing the hit for debugging
use only.charIndex.
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.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:
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.
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:
notify method
or the notifyAll method.
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.