<Swing Dev> [9] Review request for 8048110: Using tables in JTextPane leads to infinite loop in FlowLayout.layoutRow

[dmitry markov]

Hello Sergey,

LogicalView.forwardUpdate() sends update event to all views followed by 
the changed place. This event will cause view to drop the cache and 
re-calculate its break points. This method was added under JDK-8024395 
<https://bugs.openjdk.java.net/browse/JDK-8024395> and intended for the 
documents contained only text elements. The current implementation does 
not expect that non-text element, (e.g. a table) can be added to the 
document.
If the table is added to the document with flow layout, the invocation 
of LogicalView.forwardUpdate() will produce some negative visual effects 
(table will be displayed several times). In case of replacing the text 
by the table the situation much worse, since the FlowView will try to 
re-layout the removed text and hangs.

We have to send the update events to all instances of GlyphView followed 
by changed place for proper text line breaks calculation, see 
JDK-8024395 <https://bugs.openjdk.java.net/browse/JDK-8024395>, 
JDK-8014863 <https://bugs.openjdk.java.net/browse/JDK-8014863>. That's 
why I added checks for GlyphView instance. I understand this might be 
not a good place, but only here we have information about all views in 
the document and can forward update to them, if any.
Please note another approach to solve the problems with line breaks 
calculation - re-calculate break spots any time when a view is laid out. 
As far as I know it is used in jdk6, but this solution is not suitable, 
since it causes serious performance problems in case of large documents.

Also I have updated the fix. New version - 
http://cr.openjdk.java.net/~dmarkov/8048110/jdk9/webrev.01/
Now LogicalView.forwardUpdate() sends update only to GlyphView followed 
by the changed place. This resolves the problem when the table is 
located in the middle of the text line.

Thanks,
Dmitry

On 15/08/2014 12:56, Sergey Bylokhov wrote:
> Hello, Dmitry.
>>> The LogicalView.forwardUpdate() should send an update event to the views
>>> followed by the changed place, only when an instance of GlyphView has
>>> changed; otherwise it should invoke View.forwardUpdate() to handle the
>>> update properly.
> Can you share additional information about the fix. Why LogicalView should send an update if GlyphView was changed only. Because before the fix LocalView knows nothing about GlyphView.
>
> Thanks,
> Dmitry

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