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Bug 103936 - Enhance JPDA breakpoints
Summary: Enhance JPDA breakpoints
Alias: None
Product: debugger
Classification: Unclassified
Component: Java (show other bugs)
Version: 6.x
Hardware: All All
: P2 blocker (vote)
Assignee: Martin Entlicher
Depends on:
Blocks: 43066 58799 65015 90141
  Show dependency tree
Reported: 2007-05-14 18:55 UTC by Martin Entlicher
Modified: 2010-04-29 09:33 UTC (History)
0 users

See Also:
Exception Reporter:

The textual diff of the API change. (27.21 KB, text/plain)
2007-05-14 19:19 UTC, Martin Entlicher
Hit counts filter moved to org.netbeans.api.debugger.Breakpoint (6.67 KB, text/plain)
2007-05-15 18:16 UTC, Martin Entlicher

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Description Martin Entlicher 2007-05-14 18:55:43 UTC
In order to be able to implement some enhancements and bugfixes (like #43066,
#90141) and catch-up with JDI capabilities, we need to add support for new
breakpoint properties into the debugger JPDA API.

These are in particulatar: class filters for ExceptionBreakpoint, instance and
thread filters for FieldBreakpoint, MethodBreakpoint and LineBreakpoint, method
signature for MethodBreakpoint and hit counts for all breakpoint types.
Comment 1 Martin Entlicher 2007-05-14 19:19:15 UTC
Created attachment 42387 [details]
The textual diff of the API change.
Comment 2 Martin Entlicher 2007-05-14 19:27:36 UTC
Please review this enhancement of capabilities of JPDA breakpoints.
These are just setters/getters. I'll write test for the correct behavior of the
implementation classes shortly...
Comment 3 ivan 2007-05-14 21:37:01 UTC
Hit counts are a big bread-and-butter of intermediate debugging.
We should also strive to make converge the native and java bpt dialogs
and having a common count UI would be very beneficial.

Has there been any UI study into their use cases? 
For example, why an equals and a greater than? 
I'm also curious whatthe user-case for multiple-of
is. I've seen it in MSVC but could never figure where it comes

The hardest things to know with bpt counts is actually what to make the
count be. The use-case is typically as follows: 
some NPE or SEGV occurs. 
user wants to stop at a bpt the last time before the segv. 
user sets the btp count to a very high number and runs the app and gets
the NPE or SEGV. The current bpt count is the desired count.

for this dbx and SunStudio has three things:
A distinction between a bpt limit and a bpt count. The bpt fires when
the count hits the limit.
An artificial "infinity" count limit.
An action that assigns the current count to the count limit.
Comment 4 Martin Entlicher 2007-05-15 11:20:13 UTC
It's true that the hit count is not Java-specific, so we should probably move it
from org.netbeans.api.debugger.jpda.JPDABreakpoint into
org.netbeans.api.debugger.Breakpoint. So that it can be used by all debuggers.

I'm not so sure about the common UI. We could append the GUI components for
setting the hit count into the customizer in
org.netbeans.modules.debugger.ui.actions.AddBreakpointPanel, but I would rather
leave it on individual breakpoint customizers, because it might not fit together
nicely if it would be assembled by debugger core.

Regarding the UI study, I've started with two issues we have for this: issue
#58799 and issue #90141. Then I've searched mailing lists:
Unfortunately the serach of mailing lists is too primitive to be able to find
more user reports :-(
Other IDEs mostly add just "Hit Count" field into the breakpoint properties. Like:
Some of them suspends execution of a thread the n-th time it is hit, but never
again, until it is re-enabled or the hit count is changed or disabled (IBM Web
Sphere, BTW: this is also the behavior of JDI API) and some of them pauses
execution when the hit count is higher than the value in the Skip Hits field.
MSVC has the most rich functionality (as you've mentioned):

All three cases have their uses, so I've decided to include them all. IMHO users
use breakpoint counts mostly for tracking application state. E.g. you need to
stop in 5th iteration of some cycle and procceed from there, or watch a value of
some variable each 100th iteration, etc. Conditions can not be used in all cases
and then the hit count is useful.

In Java debugger we can not show the current hit count. This information is not
available from JDI. Thus your use-case with infinite hit count would not work in
JPDA, because it will not tell you the current hit count upon an error. Counting
it manually in debugger would lead to performance degradation. But C/C++
debugger can provide the current hit count number if it knows it, of course.
Comment 5 Martin Entlicher 2007-05-15 18:16:55 UTC
Created attachment 42425 [details]
Hit counts filter moved to org.netbeans.api.debugger.Breakpoint
Comment 6 Martin Entlicher 2007-05-15 18:19:32 UTC
So I've moved the hit count filter into org.netbeans.api.debugger.Breakpoint.
Comment 7 Martin Entlicher 2007-05-22 11:11:07 UTC
Thanks for the review, I'll commit the change later today...
Comment 8 Martin Entlicher 2007-05-22 15:23:42 UTC
The API change is integrated in trunk:

/cvs/debuggerjpda/api/apichanges.xml,v  <--  apichanges.xml
new revision: 1.23; previous revision: 1.22

/cvs/debuggerjpda/api/,v  <--
new revision: 1.24; previous revision: 1.23

new revision: 1.5; previous revision: 1.4

new revision: 1.6; previous revision: 1.5

new revision: 1.20; previous revision: 1.19

new revision: 1.10; previous revision: 1.9

/shared/data/ccvs/repository/debuggercore/api/apichanges.xml,v  <--  apichanges.xml
new revision: 1.10; previous revision: 1.9

/shared/data/ccvs/repository/debuggercore/api/,v  <--
new revision: 1.16; previous revision: 1.15

new revision: 1.8; previous revision: 1.7
Comment 9 Quality Engineering 2010-04-29 09:33:10 UTC
Verified ... and Closing all issues resolved into NetBeans 6.7 and earlier.