April 2007 - jboss-dev-forums - Jboss List Archives

[Design of Messaging on JBoss (Messaging/JBoss)] - JBoss common vs common core, common logging etc

by timfox

JBM 1.2.x depends on common-core common-logging-log4j common-logging-spi but JBAS 4.2 depends on jboss/common. My assumption is we depend on the core, logging etc so as not to have to drag in the entire jboss common jar. My question is though, how do I know what version of common-core, common-logging etc is compatible with what version of jboss common? We are currently using common-core 2.2. JBAS 4.2 will be using jboss common 1.2.GA. How do I know if these are compatible, so we can deploy unscoped? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4039830#4039830 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4039830

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[Design the new POJO MicroContainer] - Re: New Callback and error handling

by alesj

"adrian(a)jboss.org" wrote : | An error in a callback should just be logged as a warning about the broken | callback, not stop the original referenced service from being installed. Now all callback invocation error's are suppressed - meaning that context proceeds to next state anyway - if dependencies (cardinality dependency, ...) are satisfied. I also changed the order on the uninstall to be asymmetric. Is this now OK? Or should I add additional error, log, ... handling? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4039821#4039821 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4039821

19 years, 1 month

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[Design of JBoss jBPM] - Re: about actions behavior

by kukeltje

wrong forum View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4039811#4039811 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4039811

19 years, 1 month

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[Design of JBossCache] - Re: Channel creation - mux vs. old style

by manik.surtani＠jboss.com

Dos it make sense to support both approaches? Perhaps for non-AS usage where doing a lookup makes sense? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4039809#4039809 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4039809

19 years, 1 month

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[Design the new POJO MicroContainer] - Re: New Callback and error handling

by alesj

"adrian(a)jboss.org" wrote : P.S. When I say "pseudo code" like I did here: | http://www.jboss.com/index.html?module=bb&op=viewtopic&t=105187 | | It means I've omitted things like error handling, logging and the real implementation | details (which are usually more involved), etc. for clarity. | | You should not omit them in the real code! :-) I already hacked more than 100 classes, so if there was already all the error, logging, ... code commited in as well, I doubt your hard discs could take it. :-) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4039806#4039806 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4039806

19 years, 1 month

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[Design the new POJO MicroContainer] - Re: New Callback and error handling

by adrian＠jboss.org

P.S. When I say "psuedo code" like I did here: http://www.jboss.com/index.html?module=bb&op=viewtopic&t=105187 It means I've omitted things like error handling, logging and the real implementation details (which are usually more involved), etc. for clarity. You should not omit them in the real code! :-) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4039805#4039805 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4039805

19 years, 1 month

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[Design the new POJO MicroContainer] - Re: New Callback and error handling

by alesj

"adrian(a)jboss.org" wrote : I haven't looked at the new Callback code (InstallItems) in any detail yet, | but I noticed immediately that the error handling is insufficient and can lead to inconsistent behaviour/state. | Yup, I was waiting for some input, that's why I didn't close the JIRA task yet. ;-) "adrian(a)jboss.org" wrote : | 1) It should be asymmetrical with the install() | | | | // Reverse order of the install()! | | removeCallbacksFirst(); | | context.uninstall(); | | | Yes, I though of that. But I need the uninstalling context to actually change its state. For the CollectionCallbackItem to get its collection right on the uninstall phase - not picking up the current uninstalling context. But I'll try fix this. "adrian(a)jboss.org" wrote : | Let's not make the same mistakes with the new Microcontainer! :-) :-) Agreed. Will add the necessary error handling. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4039804#4039804 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4039804

19 years, 1 month

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[Design the new POJO MicroContainer] - Re: New Callback and error handling

by adrian＠jboss.org

Finally on the main callback code (not what I've shown above but it has the same problems!), its questionable whether an error in a callback should stop the main bean from being installed anyway? This potentially represents a DOS attack! | public | @Install | public void dosAttack(DataSource ds) | { | throw new Error("Nobody can register a DataSource!"); | } | An error in a callback should just be logged as a warning about the broken callback, not stop the original referenced service from being installed. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4039800#4039800 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4039800

19 years, 1 month

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[Design the new POJO MicroContainer] - Re: New Callback and error handling

by adrian＠jboss.org

The code really needs to be refactored such that the core install and before/after methods (the callbacks currently implement only the after pattern) are handling atomically and consistently. e.g. In the pseudo code I posted above: 1) An error in one of the callbacks needs to unwind any previously successful callbacks already invoked (not all of them) and then do the main uninstall() 2) If there is an error in the main install(), we don't even want to try to reverse the callbacks since they were never invoked in the first place. You can find an example of this kind of error handling in the MainDeployer/DeployerWrapper. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4039796#4039796 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4039796

19 years, 1 month

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[Design the new POJO MicroContainer] - New Callback and error handling

by adrian＠jboss.org

I haven't looked at the new Callback code (InstallItems) in any detail yet, but I noticed immediately that the error handling is insufficient and can lead to inconsistent behaviour/state. Take the old implement of incrementState() | try | { | install(); | updateInternalStateWithSuccess(); | } | catch (Throwable t) | { | error = t; | } | finally | { | handleErrorHere(); // Invokes uninstall() back to NOT_INSTALLED (then *ERROR*) | } | This code is consistent. It either works and updates the state or if the error flag has been set it always returns the context to "not installed". Now we have: | try | { | install(); | updateInternalStateWithSuccess(); | handleCallbacks(); // NEW Code | } | catch (Throwable t) | { | error = t; | } | finally | { | handleErrorHere(); | } | The uninstall() includes the unwinding of the new callbacks. This looks ok? Although it is potentially lazy code. I haven't checked all the codepaths, to see if it really works. Better would be: | try | { | install(); | updateInternalStateWithSuccess(); | try | { | handleCallbacks(); // NEW Code | } | catch (Throwable t) | { | error = t; | } | finally | { | // Reverse the already succesful install() | } | } | catch (Throwable t) | { | error = t; | } | finally | { | handleErrorHere(); | } | Although I think uninstall() is potentially doing this anyway, I'd be more confident of that fact if the there was a nested try/catch block. The real problem is the uninstall(). It has two problems. 1) It should be asymmetrical with the install() | // Reverse order of the install()! | removeCallbacksFirst(); | context.uninstall(); | 2) It really does need multiple try/catch blocks. uninstall() should ATTEMPT to reverse all the changes of install() Currently it is not doing this. Previous code: | try | { | context.uninstall(); | } | catch (Throwable t) | { | // If the callout doesn't work, at least we tried. | // But continue as it if it did otherwise the state will be inconsistent. | } | New Code: | try | { | context.uninstall(); | removeCallbacks(); | } | catch (Throwable t) | { | // An error in uninstall() will come here meaning callbacks are not removed! | } | This code reminds me of the horribly poor implementation of a State Machine in the old ServiceController where I went through and fixed the most obvious problems with the error handling a few years ago. Let's not make the same mistakes with the new Microcontainer! :-) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4039793#4039793 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4039793

19 years, 1 month

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jboss-dev-forums April 2007