ReflectObject loses command

Tom Poindexter — Mon, 25 Aug 2008 04:53:10 -0000

There seems to be a situation where a Java Object command is
deleted from the interpreter, but the object still resides
in the interp.reflectObjTable. This patch causes the
java object command to be re-created if the command no
longer exists.

Note that this bug is exposed when using Incr Tcl, I'm not sure
if there are other cases where the bug is exposed.

Also note: my first attempt at a patch simply invoked
interp.createCommand() if the command was missing, but
that yielded "reflected object is no longer valid" when used (from the
cmdProc() method.)

---------------------------------------------------------------------------------

IncrTcl method that exposes the bug, part of Aejaks 'Table' class.
(The ::Label constructor '-from $c' wraps up an existing Java
object, rather than creating a new one.)

----------------------------------------------------------------------------------

public method setCellLabelAttrs {columnIdx rowNum args} {
if {[catch {
set c [::java::cast [::Label::_getObjType_] [$_obj_ -noconvert getCellComponent $columnIdx $rowNum]]
puts "getCellComponent return object $c"
puts "check for command defined: [info commands $c]"

set label [::Label #auto -from $c]
} result]} {
error "invalid column or row, or cell component is not a Label: $result"
}
set result ""
set rc [catch {eval $label configure $args} result]
::itcl::delete object $label
if {$rc} {
error $result
} else {
return $result
}
}

----------------------------------------------------------------------------------

Test case, first time works; second time through, the java object command is
missing. This example creates a table with one row and two columns.
Invoking the 'setCellLabelAttrs' method changes the foreground color and text
of the Label in the first column. The first invocation works (setting the
text as 'RED' and changes its color to red.) The second invocation fails,
as the java object command no longer exists. The error raised is a result
of the 'from $c' missing the java object command.
----------------------------------------------------------------------------------
% Table .t -columns 2
% Pack .t
% .t insertRow 0 {first second}
% .t setCellLabelAttrs 0 0 -foreground red -text RED
%
getCellComponent return object java0x66
check for command defined: java0x66

% .t setCellLabelAttrs 0 0 -foreground blue -text BLUE
%
getCellComponent return object java0x66
check for command defined:
invalid column or row, or cell component is not a Label: unknown option "-from"

Recent changes to 47: ReflectObject loses command

ReflectObject loses command