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<a href="http://community.jboss.org/index.jspa" style="text-decoration: none; color: #E1E1E1">JBoss Community</a></h1>
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How to handle failed processes/states due to server crashes?
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reply from <a href="http://community.jboss.org/people/mrinneL1">Michael Rinne</a> in <i>jBPM</i> - <a href="http://community.jboss.org/message/555485#555485">View the full discussion</a>
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<div class="jive-rendered-content"><p>Hi,</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Concerning exception handling, I saw that advice to take care of exceptions in the user code a couple of times in this forum, but I am not totally convinced that this is capable to handle all cases that arise in BPM.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Let us assume I have a process definition containing the sequence state1 -> task1 -> task2 -> state2. Let us further assume there is some sort of dependency between task1 and task2, i.e. if task2 fails we have to perform some kind of undo for task1. If I handle exceptions within the user code for task2 I am not able to undo task1, because I do not want task2 to know about task1. For the same reason, I do not want to combine task1 and task2 into a single task.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>The solution in jpdl 4 seems to be adding another transition from task2 to a task "undo_task1" and any exception in task2 will make sure that we take the transition to "undo_task1". Another transition from "undo_task1" will lead back to state1 and of course we add a decision in order to prevent processing from taking this circle endlessly.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>However, an <code>exception-handler </code>as provided by jpdl 3 seems to be a convenient way to handle most exceptions on a BPM scale, although it will most likely not be as flexible as the explicit solution sketched above.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>What are you opinions on this?</p><p>Does anyone have a better idea on how to do exception handling on BPM scale with jpdl 4?</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Thanks,</p><p>Michael</p></div>
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