set conditional breakpoints in idea
This blog post is ancient. If it is technical, the information is likely inaccurate, or at least out of date. If it is non-technical, it’s entirely possible that the relevant facts and my own opinions have changed significantly since it was written.
It is only preserved as part of this site’s permanent historical archive.
So yesterday I was attempting to debug an issue in a batch processing module within one of our applications. In short, an assertion was failing deep within Hibernate as it attempted to flush the session. Using a combination of various log statements, I had isolated the problem down to a particular record that the batch process was attempting to update. (BTW: I know you shouldn’t be using Hibernate for batch processing - however, we’re talking about batches of at most 1000 records here, not millions!) What I really wanted to do was set a breakpoint and examine the state of the objects at runtime; however, I dreaded the thought of clicking through the breakpoint time and time again until I got to the particular record that was causing the problem. “Surely,” I thought, “there must be a way to tell the debugger to only break under certain conditions.”
So, here’s the code I wanted to examine:
<br></br>public Publication parsePublication(String inputLine)<br></br> throws ParseException {<br></br> Publication publication = new Publication();<br></br><br></br> String[] fields = inputLine.split("\t");<br></br><br></br> publication.setPublicationType(fields[0]);<br></br> ...<br></br> return publication;<br></br>}<br></br>
Essentially, I wanted to break after inputLine.split("\t"); if and only if fields[35] existed and was equal to “PM:16732581.” After examining IDEA’s Breakpoint dialog, I noticed a section in the bottom right-hand corner that I’d never played with before:
As it turns out, this is exactly what I needed. If you click on the ellipsis next to the drop menu, you get a context-sensitive editor equipped with code completion:
Enter the desired conditions and voila! A conditional breakpoint. It worked like a charm the very first time, and I only had to inspect the breakpoint when the problematic record came up.
Another nice feature of the conditional breakpoint is that if some sort of exception (such as a NullPointerException) occurs while attempting to evaluate the conditional expression, IDEA pops up a dialog informing you what happened and asking if you want to stop at the breakpoint or continue. Nice.