While I'm still waiting for some answers to the questions outlined
below, I also just recalled another issue.
About a year ago or so we developed a fix to replace the components
array with a collection in the Container class. The initial version of
the fix included synchronized (getTreeLock()) sections in such methods
like countComponent(), getComponent(int), and some other. I recall we
indeed faced dead-locks back then, and decided that a developer must
hold the lock when calling these methods, so that we could avoid
acquiring the lock ourselves.
How does that decision correspond to the current proposal of forcibly
getting the lock in the preferredSize(), paramString(), some Swing
methods, and others? Wouldn't that be safer to shift the responsibility
of holding the lock to the user's code instead (as just assumed
currently, in fact)?
--
best regards,
Anthony
On 10/08/2009 01:04 PM, Anthony Petrov wrote:
On 10/8/2009 12:34 PM Artem Ananiev wrote:
Artem, would you agree on placing all calls to the isValid() under
the TreeLock?
Yes, that would be fine. Have we already introduced a warning about
all
OK, I'll modify the fix for 6887249 accordingly.
Well, I revised the code, and it appears that the 'valid' boolean
field is declared volatile. Which basically means that we should only
acquire a lock when we need an atomic "read-then-update" sort of
operation (like validate() or invalidate() do.) When we need to read
the value of this field only w/o subsequent updating it, we don't
actually need any locking at all. So I tend to think that the fix for
6887249 should modify the Container.validate() method only. What do
you think?
If isValid() were a final method that just returns a value of
'isValid' field, then yes, we wouldn't have to provide any external
synchronization. However, users might want to override isValid(), so
I'd better place all the calls to isValid() under the tree lock.
What about the Component.paramString() method then? Couldn't it produce
some dead-locks while debugging is in progress?
Also, there's a number of isValid() calls in the Swing code (e.g.,
JViewport, BasicTabbedPaneUI, and possibly some more.) Should these be
modified as well? Alex, what's your opinion?
--
best regards,
Anthony
