If I understood you correctly:
- Make option relationship from tUser <-->> tA for "user-owned templates"
- Add extra fields to tA
- Add a type field to tA - Integer - each int denotes a behavior
- Use Strategy Design pattern and create 2 behavior classes that correspond to
two templates types
TemplateBehavior interface
DefaultTemplateBehavior
UserTemplateBehavior
- Methods/logic that differ between both template scenarios should be put in
the Behavior interface and implemented in Behavior classes.
- The EO class corresponding to tA also implements TemplateBehavior interface.
- Set default value of type to be DefaultTemplateBehavior type (say type = 10)
- lazy instantiate behavior in the class based on value of type.
private TemplateBehavior _behavior;
private TemplateBehavior behavior() {
if ( _behavior == null) {
if (type().intValue() == 20) {
_behavior = new UserTemplateBehavior(this);
} else {
_behavior = new DefaultTemplateBehavior(this);
}
}
return _behavior;
- implement interface methods in the EO class like this
public void doSomething() {
behavior().doSomething();
}
- Use Chuck's EOCopyable interface and utilities to copy tA instance when a
user wants to customize. Set your extra attrivutes and change the type of the
copied template to the int corresponding to the UserTemplateBehavior (and reset
_behavior to null - I have a reset() method in my GenericEO and is used to
nullify cached ivars on every didUpdate and didInsert btw)
HTH, Kieran
On May 11, 2011, at 3:14 PM, Michael Gargano wrote:
> I was just talking to David Holt about this and he suggested I tap the brain
> trust. :)
>
> I was wondering if there is a database design pattern for a situation where I
> have some template structure
> let's say
>
> tA <->> tB <->> tC (records across these tables are the template, the
> template is a whole object graph rooted at one record in tA)
>
> where the templates can be configured on a per tenant basis (so, the
> templates themselves are records that define defaults and new ones can be
> added when new tenants or templates are added). I need to make a copy of a
> template that a tenant uses and make it local to a user (under that tenant)
> who can then customize the values in that template for their needs.
>
> It's basically a class/instance kind of structure, but at the data level in
> the database. It's as if I need to copy an EOs from one table to another
> where the destination table has a few more attributes than the source table
> did. It's made more complicated by the fact that I need to copy that
> template object graph, not just one EO.
>
> Any suggestions?
> *Hopes beyond hope*
>
> Thanks.
> -Mike
>
> _______________________________________________
> Do not post admin requests to the list. They will be ignored.
> Webobjects-dev mailing list ([email protected])
> Help/Unsubscribe/Update your Subscription:
> http://lists.apple.com/mailman/options/webobjects-dev/kelleherk%40gmail.com
>
> This email sent to [email protected]
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Webobjects-dev mailing list ([email protected])
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com
This email sent to [email protected]
