[CFCDev] How to avoid duplication of objects

[Marcantonio Silva]

Hello,   This seems to be a design problem to me (but could also be ignorance) and maybe somone can see a better way:   I'm working with a DAO and a Gateway for, lets say, multiple article retrieve, I have a DAOFactory that instantiates the DAO depending on the type (eg: MSSQL, ORA etc). I want a struct of article objects, so what I do is send a getArticles() to the gateway, it runs a query, loops over it and creates one object for each row, storing them in the struct:   [articleGateway.cfc getArticles()]: cfset stArticles = structNew() [loop over articlesGateway]     stArticles[key] = createObject("component","article").init(stConfig).getArticle(query values) [/end loop] return stArticles     Inside the bean I init the DAO from the factory:   [article.cfc init()]: cfset variables.articleDAO  = createObject("component","model.factory.DAOFactory").init(arguments.stConfig).getDAOFactory(factoryType:arguments.stConfig.dbtype).getArticleDAO(arguments.stConfig)     First I had this in the constructor, but then I decided to move the "stConfig" from the constructor to the init, in order to avoid duplication of the XML functions that are parsed everytime I instatiated the config.cfc.init() method (actually, I got it under the application scope, but didn't feel right to have dozens of calls to the method, so I decided moving it with every call to init methods on my app, like Mach-ii dos with the appManager).   The problem is that everytime an articleBean is instantiated it has to call the DAOFactory, and eventually this will start decreasing performance at runtime. So if I have to instantiate, lets say, 20 articles, I would have to init the DAOFactory 20 times, it dosen't seem right.   To resolve the problem, I could instantiate the DAO once, and send it to the init() method of the article everytime, but this seems an overkill: (eg: stArticles[key] = createObject("component","article").init(stConfig,articleDAO).getArticle(query values)   I would also have the article bean init() depending on receive the DAO, which I don't want, since sometimes I want to create a blank article, or even an article populated by a form, and I dont need a DAO for doing this.   What I could do, if I could use my old CF skills woul be:     [article.cfc init()]: <cfif NOT isDefined("request.articleDAO")>     <cfset request.articleDAO = createObject("component","model.factory.DAOFactory"). ... /> </cfif> <cfset variables.articleDAO  = request.articleDAO >     This way I wouldn't have 20 instantiations of the DAO, but it doesn't seem right too ... I shouldn't be allowd to use the request scope, should I ?   I guess this could be done with a singleton for managing the DAOFactory, and instead of creating it everytime I could get it from the singleton, but is this right design ? Is there any better way of doing this ?   []s Marcantonio Silva Product Development - ContentObjects [EMAIL PROTECTED] www.contentobjects.com Phone: +55 11 3055.2004 Mobile: +55 11 7732.4907