Re: [Zope3-Users] Complex Adapter Requirements - Named Adapters?
On 12/11/05, Stephan Richter [EMAIL PROTECTED] wrote: On Sunday 30 October 2005 14:16, James Allwyn wrote: One thought I had, was creating an interface IStandard, with attributes like meetsstandard and nameofstandard, and then subclass this, e.g. to IAccreditationScheme and INationalCode (where Accreditation Scheme and National Code are the names of two of the standards). But I get a little stuck conceptually at the point where I try to handle, for example, the fact that for some ISharedHouse objects, IAccreditationScheme would be suitable, whilst for others it wouldn't, because of their location. In fact it's likely that in the future we will need to recognise two or more standards for a particular accommodation type (so IAccreditationScheme and IHouseCheck chould both apply to ISharedHouse objects, in differect areas). This is not such a complex case as you think. If you register an adapter from ISharedHouse to IAccreditationScheme then it will be only available for this interface and not for IAccommodation in general. I would even write a specific IAccreditationScheme for every scheme you support; thus you do not even need named adapters. OK, so by targeting the registration of the adapter I can make sure each adapter is not available for types of accommodation object that it would not apply to. I'm with you on that. My thoughts about named adapters were related to the 'other side of the coin', where I have more than one scheme (and hence adapter) that would apply to one type of accommodation (for example the schemes represented by IAccreditationScheme and IHouseCheck would both apply to ISharedHouses). I guess what I want is to have both IHouseCheck and IAccreditationScheme available for ISharedHouses *in general*, and to select either (or none) for a given *instance* of ISharedHouse. Are named adapters the way to go for this requirement, or am I not understanding some mechanism in Stephan's suggestion that makes this possible without invoking that level of complexity? Thanks for the guidance so far. James ___ Zope3-users mailing list Zope3-users@zope.org http://mail.zope.org/mailman/listinfo/zope3-users
Re: [Zope3-Users] Complex Adapter Requirements - Named Adapters?
On Sunday 30 October 2005 14:16, James Allwyn wrote: One thought I had, was creating an interface IStandard, with attributes like meetsstandard and nameofstandard, and then subclass this, e.g. to IAccreditationScheme and INationalCode (where Accreditation Scheme and National Code are the names of two of the standards). But I get a little stuck conceptually at the point where I try to handle, for example, the fact that for some ISharedHouse objects, IAccreditationScheme would be suitable, whilst for others it wouldn't, because of their location. In fact it's likely that in the future we will need to recognise two or more standards for a particular accommodation type (so IAccreditationScheme and IHouseCheck chould both apply to ISharedHouse objects, in differect areas). This is not such a complex case as you think. If you register an adapter from ISharedHouse to IAccreditationScheme then it will be only available for this interface and not for IAccommodation in general. I would even write a specific IAccreditationScheme for every scheme you support; thus you do not even need named adapters. Regards, Stephan -- Stephan Richter CBU Physics Chemistry (B.S.) / Tufts Physics (Ph.D. student) Web2k - Web Software Design, Development and Training ___ Zope3-users mailing list Zope3-users@zope.org http://mail.zope.org/mailman/listinfo/zope3-users
[Zope3-Users] Complex Adapter Requirements - Named Adapters?
Hi, My project has an IAccommodation object type, representing a generic housing unit, from which we subclass several types of housing (ISharedHouse, IFamilyHouse, ILargerDevelopment,...). Now, we need to recognise various standards in relation to these accommodation units - these are standards that have been defined by various local councils etc, and an accommodation unit typically has to meet certain conditions before it can be deemed to meet that standard. A property that meets a standard is deemed to be better than one that doesn't. However, there is a degree of complexity to these standards... * Different standards will apply to different accommodation types. * Some accommodation types will have no relevant standard. * Some standards will apply to an accommodation type in some geographic areas but not other areas. One reason we want to handle these standards is to be able to rate the accommodation. E.g., a house that wasn't part of the Accreditation Scheme standard could appear lower in search results than one that was. Naturally, where there is no relevant standard for an accommodation to live up to, we do not want to penalise it in this way (or possibly would want it to appear below those that do meet a standard, and those that don't meet a standard but could...) Now, I believe I should be defining an interface or interfaces for standards and using adapters to adapt my Accommodation Objects to the 'standards' interface(s). My question is, how best to handle the complexity I've outlined above? One thought I had, was creating an interface IStandard, with attributes like meetsstandard and nameofstandard, and then subclass this, e.g. to IAccreditationScheme and INationalCode (where Accreditation Scheme and National Code are the names of two of the standards). But I get a little stuck conceptually at the point where I try to handle, for example, the fact that for some ISharedHouse objects, IAccreditationScheme would be suitable, whilst for others it wouldn't, because of their location. In fact it's likely that in the future we will need to recognise two or more standards for a particular accommodation type (so IAccreditationScheme and IHouseCheck chould both apply to ISharedHouse objects, in differect areas). I recalled reading in Philipp's book about Named Adapters, but looking back I can only find brief references to them. A 'search' through the PDF of Stephan's book reveals no instances of the phrase named adapter (or variations). Are these something I should be looking into, and if so, where can I read up on them? Or does anyone have any other suggestions on handling this? Many thanks, James ___ Zope3-users mailing list Zope3-users@zope.org http://mail.zope.org/mailman/listinfo/zope3-users
