Details
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Type:
Improvement
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Status:
Closed
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Priority:
Blocker
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Resolution: Fixed
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Affects Version/s: 1.0-beta-5
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Fix Version/s: 1.0-beta-4
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Component/s: PicoContainer (Java)
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Labels:None
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Number of attachments :
Description
There is one single thing that is worse than a two-way relationship, and that is a many-to-many two-way relationship. PicoContainer currently has both. 
(A container can have several parents.)
The amount of code needed to maintain this relationship is actually a large percentage of the entire PicoContainer!!
If someone really, really needs it state your reasons here. I think it can (and should) be solved as a PicoExtra-extension to the default PicoContainer.
Related to PICO-92.
This needs to be resolved before 1.0.
Activity
From the mailing list:
I know Leo Simons has reasons for it to be supported, but I'm thinking whether it would be possible to do something in PicoExtras for this.
I think Paul had written something previously that made a set of PicoContainers look like one single PicoContainer. Is that still around? That would be the best solution! You could use that "multi-container" as the (single) parent if you ever needed multiple parents.
Joe Walnes wrote:
> Uhhmm I can't remember why I'd ever need more than one parent, so ditch it (until I remember).
>
> -joe
Jon Tirsen
added a comment - From the mailing list:
I know Leo Simons has reasons for it to be supported, but I'm thinking whether it would be possible to do something in PicoExtras for this.
I think Paul had written something previously that made a set of PicoContainers look like one single PicoContainer. Is that still around? That would be the best solution! You could use that "multi-container" as the (single) parent if you ever needed multiple parents.
Joe Walnes wrote:
> Uhhmm I can't remember why I'd ever need more than one parent, so ditch it (until I remember).
>
> -joe It is a no-brainer to support multiple parents with a (GoF) aggregating proxy for PicoContainer - even if the API says one parent only. It's just a special implementation of PicoContainer that delegates to a set of others. This belongs in PicoExtras IMO.
Paul wrote something like this, yes. I refactored it away. It's time to add it back in 
Aslak Hellesøy
added a comment - It is a no-brainer to support multiple parents with a (GoF) aggregating proxy for PicoContainer - even if the API says one parent only. It's just a special implementation of PicoContainer that delegates to a set of others. This belongs in PicoExtras IMO.
Paul wrote something like this, yes. I refactored it away. It's time to add it back in Thanks 
Paul Hammant
added a comment - Thanks Aslak wrote: "It is a no-brainer to support multiple parents with a (GoF) aggregating proxy for PicoContainer."
LSD goes to hide in a corner, because so true it is. Forget I said anything.
Leo Simons
added a comment - Aslak wrote: "It is a no-brainer to support multiple parents with a (GoF) aggregating proxy for PicoContainer."
LSD goes to hide in a corner, because so true it is. Forget I said anything. Jon Tirsen
made changes -
| Field | Original Value | New Value |
|---|---|---|
| Fix Version/s | 1.0-beta-4 [ 10412 ] | |
| Fix Version/s | 1.0 [ 10145 ] |
Jon Tirsen
made changes -
| Component/s | Core (Java) [ 10191 ] |
Jon Tirsen
made changes -
| Assignee | Jon Tirsen [ tirsen ] |
Aslak Hellesøy
made changes -
| Assignee | Jon Tirsen [ tirsen ] | Aslak Hellesoy [ rinkrank ] |
Aslak Hellesøy
made changes -
| Status | Open [ 1 ] | In Progress [ 3 ] |
In progress on SINGLE_PARENT_REFACTORING branch in CVS.
Aslak Hellesøy
added a comment - In progress on SINGLE_PARENT_REFACTORING branch in CVS. Aslak Hellesøy
made changes -
| Status | In Progress [ 3 ] | Closed [ 6 ] |
| Resolution | Fixed [ 1 ] |
Multiple parents is vital.
Example: I have an avalon-fortress container holding avalon components, a spring factory holding javabeans, an eob container holding enterprise objects, a pico container holding type 3 objects.
I really want the ability to aggregate these together and use them as one container. The only way that's currently feasible with pico is to use them as parents:
public void testMultipleParents()
{ Container fc = getFortressContainer(); PicoContainer pfc = getPicoContainer( fc ); BeansFactory bf = getSpringBeanFactory(); PicoContainer pbf = getPicoContainer( bf ); BeanBroker bb = getBeanBroker(); PicoContainer pbb = getPicoContainer( bb ); MutablePicoContainer c = getPicoContainer(); c.addParent( pfc ); c.addParent( pbf ); c.addParent( pbb ); // can now access things from c, fc, bf and bb through // my 'c' reference }do note that it is possible to remove the notion of hierarchies but retain this use case. But that will require significant refactoring. See my comments in
PICO-90, PICO-91 and from Thomas on the mailing list.