BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Non DB related OPF          BorlandTalk.com Forum Index -> Delphi OO design View previous topic :: View next topic   Author Message J. França Guest Posted: Thu Feb 12, 2004 1:30 pm    Post subject: Non DB related OPF I'm trying to design a OPF, but it is not intended to represent a database. It must store my program options, window positions, plugin options. I’m using a tree-like structure where each node is associated with its storage. The program must create objects from storage when they are needed. But I have a problem with this: - Some nodes are lists where subnodes (objects) can be added and removed by users. - There are links between objects: Objects “B” and “C” can be using object “A”. - User must not delete “A” because it is used by “B” and “C”, even if “B” and “C” are not currently in use. When objects are pre-created, even if “A” does not know anything about “B” or “C”, they can add themselves to a list of “A” users, and I can test if “A” is in use. But, how can I do this without creating the whole list objects? Back to top Bryan Crotaz Guest Posted: Thu Feb 12, 2004 1:59 pm    Post subject: Re: Non DB related OPF "J. França" <jfranca123 (AT) netscape (DOT) net> wrote Quote: I'm trying to design a OPF, but it is not intended to represent a database. OPFs aren't designed to represent databases - they are designed to store objects in some form - could be XML, registry, ini files, blobs, anything! Quote: But I have a problem with this: - Some nodes are lists where subnodes (objects) can be added and removed by users. - There are links between objects: Objects “B” and “C” can be using object “A”. - User must not delete “A” because it is used by “B” and “C”, even if “B” and “C” are not currently in use. I would recommend Bold for this job - it has all this built in and can load and save to xml. If you can't afford the upgrade, you'll need some sort of MayDelete method which raises an exception in Delete if MayDelete returns false. Then have a generic MayDelete which checks a metadata flag to see if a link is a composite (ie delete prohibited if link is populated), then returns false if the link has a count of at least 1. Quote: When objects are pre-created, even if “A” does not know anything about “B” or “C”, they can add themselves to a list of “A” users, and I can test if “A” is in use. But, how can I do this without creating the whole list objects? You'll need bi-directional links between objects, so when you add A to B, B automatically gets added to A. Bryan Back to top Marc Rohloff Guest Posted: Thu Feb 12, 2004 3:16 pm    Post subject: Re: Non DB related OPF =?windows-1252?Q?=22J=2E_Fran=E7a=22?= wrote on Thu, 12 Feb 2004 09:30:15 -0400 ... Quote: I'm trying to design a OPF, but it is not intended to represent a database. It must store my program options, window positions, plugin options. I=3Fm using a tree-like structure where each node is associated with its storage. The program must create objects from storage when they are needed. What type of storage are you planning on using? Regardless I think you can design it much like any other OPF. If you want to link objects then you will need to assign unique IDs and store references with your objects. Are you expecting a finite, predetermined number of classes or do you expect users to be able to define their own ad-hoc? Marc Rohloff Back to top J. França Guest Posted: Fri Feb 13, 2004 5:26 am    Post subject: Re: Non DB related OPF Quote: I would recommend Bold for this job - it has all this built in and can load and save to xml. If you can't afford the upgrade, you'll need some sort of MayDelete method which raises an exception in Delete if MayDelete returns false. Then have a generic MayDelete which checks a metadata flag to see if a link is a composite (ie delete prohibited if link is populated), then returns false if the link has a count of at least 1. The MayDelete can be the answer... Now to implement it is other isue... My application must use multiple storage for objects, the tree isn't fully known at design time. Some nodes can be lists of files on disk and I cannot add metadata to them, but may be I can associate it in other storage (a node with the list of links?). Quote: When objects are pre-created, even if “A” does not know anything about “B” or “C”, they can add themselves to a list of “A” users, and I can test if “A” is in use. But, how can I do this without creating the whole list objects? You'll need bi-directional links between objects, so when you add A to B, B automatically gets added to A. I can do the link, but in some cases I cannot save the data in my originaly intended storage. Data must be stored in more than one place. Perhaps I must use the storage with this data (an xml node) as the main one, linking to files that store the subnodes: <list Id=”Styles” Files=”.Config*.css”> <node Id=”Style1”> <user Id=”/outputs/Renderer1”/> <user Id=”/outputs/Renderer2”/> </node> </list> If I try to delete .ConfigStyle1.css I will find it is in use even if Renderer1 and Renderer2 are not in memory now. Quote: Bryan Thanks, Jacinto Back to top J. França Guest Posted: Fri Feb 13, 2004 5:50 am    Post subject: Re: Non DB related OPF Quote: I'm trying to design a OPF, but it is not intended to represent a database. It must store my program options, window positions, plugin options. I=3Fm using a tree-like structure where each node is associated with its storage. The program must create objects from storage when they are needed. What type of storage are you planning on using? I'm trying to use multiple storage. The main node may be an xml file, but some nodes can be lists of files. Some of them other xmls. I think to use even dlls as nodes (PlugIns with node classes). Quote: Regardless I think you can design it much like any other OPF. If you want to link objects then you will need to assign unique IDs and store references with your objects. For a deep tree-like structure were some subnodes are out of my control, I cannot assign a unique ID to each item. I was thinking to use a local ID with an added path as a unique ID. Quote: Are you expecting a finite, predetermined number of classes or do you expect users to be able to define their own ad-hoc? I’m expecting multiple classes living in PlugIns. Quote: Marc Rohloff Thanks, Jacinto França Back to top Bryan Crotaz Guest Posted: Sat Feb 14, 2004 9:00 pm    Post subject: Re: Non DB related OPF I do this with a plugin object (thus can be in a dll) which is responsible for its own storage, and exposes IStreamable (remember to use Istream, not TStream). It is responsible for monitoring storage for changes, usually via singleton plugins (eg a singleton to monitor the registry) and reloading its subnodes itself. I then use Subject-Observer to notify other parts of the app of those changes. Bryan Back to top J. França Guest Posted: Mon Feb 16, 2004 1:28 pm    Post subject: Re: Non DB related OPF Bryan Crotaz wrote: Quote: I do this with a plugin object (thus can be in a dll) which is responsible for its own storage, and exposes IStreamable (remember to use Istream, not TStream). It is responsible for monitoring storage for changes, usually via singleton plugins (eg a singleton to monitor the registry) and reloading its subnodes itself. I then use Subject-Observer to notify other parts of the app of those changes. I have a node object to represent each PlugIn, but the exe is who store the objects created from it. I was not using a IStream, the storage just loads and stores the INode, writing its attributes and elements. I did not think about external changes in storage... may be I must do. The PlugIn itself is represented as a node whose subnodes are the classes it exports, one of their attributes is the factory node (its path) where they must belong. My observable implementation is a litle strange: My IObserver.DocChanged is a method that fits the Dispatch method, so if I need different messages I can write message handlers like TComponent subclasses do (My class must be not a TComponent subclass to do so): procedure IObserver.DocChanged = Dispatch; procedure CmDestroy(var Msg: TCmDestroy); message cm_Destroy; procedure CmAttributeChanged(var Msg: TCmAttributeChanged); message cm_AttributeChanged; Quote: Bryan Jacinto Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> Delphi OO design All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.