[CFCDev] Erm, DataLayer Factory Question.

[SBarnes]

The problem I have at present is I’m building an application that makes use of two different persist layers. In one install instance it will make use of “XML” files, while the other it will use a DB. The two have totally different persist logic and so I want to keep the rest of the model uniform, while the actual CRUD etc routines specific to the Data Resource type.   So below is an example of a concept I’ve been floating around in my head. The Manager is kind of a “Service” or even a “Fa�ade” I guess, but I settled on the concept of it being a manager, in that it will handle all aspects of the AppService in question? (think I answered my own question in that bit hehe).   Also keep in mind that I need to make use of a global functions or objects, and I’m not sure how to do this via Coldfusion. In other languages I would simply “import” the object and use it via its Named path (ie import com.mypkg.core.singletonManager and then use com.mypkg.core.singletonManager.createSingleton()) so what I’ve done is lifted a concept I saw at my previous work, were we kind of extended all objects to a base class of some kind which has these top level routines tucked away inside them (whether it be by a dependent object or within the extended class itself). Thus you see “createSingleton()” methods.   I also figure I would use a “DataLayer Gateway Factory“ for all my DAO/DataGateway object(s) this way I can keep the DAO/DG objects persist logic specific but via the typical “abstract factory” pattern, its transparent (well should be) to the rest of the model. So at runtime I’d pass what type the DLGatewayFactory is (XML or SQL) and it would initialize its sub-objects accordingly.   So here is the concept so far any crit is welcome. I’m using Mach-II as a bases for the Framework, thus you will see ApplicationListener, as its typically the object that initializes the entire model according to configuration settings outlayed.   Note: its in pseudo code so ignore syntax   // This is the first object that realistically starts the CFMX application (ie Application.cfm equiv) ApplicationListener extends baseListener; {   function onAppStart() {               var DataResourceBean = new com.mypkg.lib.DataResourceBean();             DataResourceBean.setType(‘SQL’); DataResourceBean.setDSN(‘MyDBDSN’); Etc // Note If you set type as “XML” you would go setLocation(‘pathToXml”) its versatile enough – that and couldn’t settle on a generic verb as I wrote this.                         // Create a singleton of the Blog DataLayer GatewayFactory (ie in application.scope) – I prefer a snapshot of the data here as the bean will not be cached.             createSingleton(‘com.mypkg.blog.DLGatewayFactory’,DataResourceBean.getMemento()); }   // Lets pretend I’m in the app now and I want to make some calls to a blogManager   blogManagerClass extends baseClass {               function getBlogEntriesByDate(dtArg) {                                                 return qryEntries = getSingleton(‘com.mypkg.blog.DLGatewayFactory’).createDG(‘Entries’).findEntriesByDate(dtArg);                                     }                         function saveBlogEntry(args..) {                                                 var EntryDAO = getSingleton(‘com.mypkg.blog.DLGatewayFactory’).createDAO(‘Entry’);                         var EntryBean = new EntryBean();                         EntryBean.setTitle(arg1);                         EntryBean.setBody(arg2);                         etc..                                                 EntryDAO.create(EntryBean);                             } }     DLGatewayFactory {                         function init(DRB) {                         instance.type = DRB.type;                         instance.dsn = DRB.dsn;                           // Even if the type is DB the location key still exists.                         instance.location = DRB.location; }   function createDAO(sDAOType) {             switch(sDAOType) {                         case “Entry”:                                     // Now here I could do switch statement based on DataResource Type, then do condition logic etc..                                     // But for now I’ll just pass the instance scope itself and pretend it’s a basic DTO. return createObject(‘component’,’com.mypkg.blog[instance.type].EntryDAO’).init(instance);                                                                         break;             }             }   }   So Yeah, hopefully the code makes sense but the purpose is that the DLGatewayFactory has a certain level of abstraction based on its type which grabs the appropriate DAO / DataGateway that’s relevant to your persist layer type.     NOW… DOES THAT HOLD WATER ehehe.. i.e. commence poking holes in my evil plan.       -------------------------------------------------- Regards, Scott Barnes Senior Network Engineer Goro Nickel Project