BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Suggestions for designing an subclass of an abstract class.          BorlandTalk.com Forum Index -> JBuilder IDE View previous topic :: View next topic   Author Message Brian Ray Guest Posted: Tue Mar 01, 2005 9:39 pm    Post subject: Suggestions for designing an subclass of an abstract class. We have an application that is an MDI (Multiple Document Interface), and we need to periodically create new child documents. Our child document abstract class is called KNetFrame, it subclasses JInternalFrame. It has some features on it (like buttons), and we want the programmer to implement the methods required for the buttons to work. For this reason, we have made the class abstract. But when the programmer wants to design his new document, the designer says that it can't instantiate the abstract class (of course not), so it jsut makes a red screen. Does anyone have any ideas on how we can get around this? Thanks! Back to top Tony Guest Posted: Tue Mar 01, 2005 9:45 pm    Post subject: Re: Suggestions for designing an subclass of an abstract cla Brian, An excellent summary of the solution can be found at: http://www.visi.com/~gyles19/fom-serve/cache/97.html Cheers, Tony. "Brian Ray" <bray (AT) kable (DOT) com> wrote Quote: We have an application that is an MDI (Multiple Document Interface), and we need to periodically create new child documents. Our child document abstract class is called KNetFrame, it subclasses JInternalFrame. It has some features on it (like buttons), and we want the programmer to implement the methods required for the buttons to work. For this reason, we have made the class abstract. But when the programmer wants to design his new document, the designer says that it can't instantiate the abstract class (of course not), so it jsut makes a red screen. Does anyone have any ideas on how we can get around this? Thanks! Back to top Kevin Dean [TeamB] Guest Posted: Tue Mar 01, 2005 9:48 pm    Post subject: Re: Suggestions for designing an subclass of an abstract cla Brian Ray wrote: Quote: We have an application that is an MDI (Multiple Document Interface), and we need to periodically create new child documents. Our child document abstract class is called KNetFrame, it subclasses JInternalFrame. It has some features on it (like buttons), and we want the programmer to implement the methods required for the buttons to work. For this reason, we have made the class abstract. But when the programmer wants to design his new document, the designer says that it can't instantiate the abstract class (of course not), so it jsut makes a red screen. Does anyone have any ideas on how we can get around this? The problem is that the designer needs to instantiate an instance of the base class in order for you to design an extended class. If you look at the release notes (setup/release_notes.html) and search for the word "proxy", you will find details on how to work around this problem. -- Kevin Dean [TeamB] Dolphin Data Development Ltd. http://www.datadevelopment.com/ NEW WHITEPAPERS Team Development with JBuilder and Borland Enterprise Server Securing Borland Enterprise Server http://www.datadevelopment.com/papers/index.html Please see Borland's newsgroup guidelines at http://info.borland.com/newsgroups/guide.html Back to top Vladislav Protasov Guest Posted: Wed Mar 02, 2005 9:32 pm    Post subject: Re: Suggestions for designing an subclass of an abstract cla Hello Brian, What version of JBuilder are you using? JBuilder 2005 has unique designer feature, it could design abstract classes. i.e. import javax.swing.*; public abstract class MyPanel extends JPanel { JButton jButton1 = new JButton(); public MyPanel() { super(); try { jbInit(); } catch (Exception ex) { ex.printStackTrace(); } } public abstract void a(); private void jbInit() throws Exception { jButton1.setText("jButton1"); this.add(jButton1); } } Best regards, Vladislav "Brian Ray" <bray (AT) kable (DOT) com> wrote Quote: We have an application that is an MDI (Multiple Document Interface), and we need to periodically create new child documents. Our child document abstract class is called KNetFrame, it subclasses JInternalFrame. It has some features on it (like buttons), and we want the programmer to implement the methods required for the buttons to work. For this reason, we have made the class abstract. But when the programmer wants to design his new document, the designer says that it can't instantiate the abstract class (of course not), so it jsut makes a red screen. Does anyone have any ideas on how we can get around this? Thanks! Back to top Vladislav Protasov Guest Posted: Wed Mar 02, 2005 9:34 pm    Post subject: Re: Suggestions for designing an subclass of an abstract cla Hi Kevin, Please see my reply Best regards, Vladislav "Kevin Dean [TeamB]" <NkOdSePaAnM (AT) datadevelopment (DOT) com> wrote Quote: Brian Ray wrote: We have an application that is an MDI (Multiple Document Interface), and we need to periodically create new child documents. Our child document abstract class is called KNetFrame, it subclasses JInternalFrame. It has some features on it (like buttons), and we want the programmer to implement the methods required for the buttons to work. For this reason, we have made the class abstract. But when the programmer wants to design his new document, the designer says that it can't instantiate the abstract class (of course not), so it jsut makes a red screen. Does anyone have any ideas on how we can get around this? The problem is that the designer needs to instantiate an instance of the base class in order for you to design an extended class. If you look at the release notes (setup/release_notes.html) and search for the word "proxy", you will find details on how to work around this problem. -- Kevin Dean [TeamB] Dolphin Data Development Ltd. http://www.datadevelopment.com/ NEW WHITEPAPERS Team Development with JBuilder and Borland Enterprise Server Securing Borland Enterprise Server http://www.datadevelopment.com/papers/index.html Please see Borland's newsgroup guidelines at http://info.borland.com/newsgroups/guide.html Back to top Gillmer J. Derge [TeamB] Guest Posted: Wed Mar 02, 2005 9:49 pm    Post subject: Re: Suggestions for designing an subclass of an abstract cla Vladislav Protasov wrote: Quote: JBuilder 2005 has unique designer feature, it could design abstract classes. But in this guy's case it's the base class that's abstract, not the class being designed. Quote: public abstract class MyPanel extends JPanel { Now try designing this: public class MyConcretePanel extends MyPanel { public void a() {} } -- Gillmer J. Derge [TeamB] Back to top Vladislav Protasov Guest Posted: Wed Mar 02, 2005 11:23 pm    Post subject: Re: Suggestions for designing an subclass of an abstract cla Works fine for me, do you see any error message? "Gillmer J. Derge [TeamB]" <spam (AT) gillmerderge (DOT) com> wrote Quote: Vladislav Protasov wrote: JBuilder 2005 has unique designer feature, it could design abstract classes. But in this guy's case it's the base class that's abstract, not the class being designed. public abstract class MyPanel extends JPanel { Now try designing this: public class MyConcretePanel extends MyPanel { public void a() {} } -- Gillmer J. Derge [TeamB] Back to top Gillmer J. Derge [TeamB] Guest Posted: Thu Mar 03, 2005 12:12 am    Post subject: Re: Suggestions for designing an subclass of an abstract cla Vladislav Protasov wrote: Quote: Works fine for me, do you see any error message? Oops! Actually, no. I hadn't tried it before, because I'm still a little afraid of the designer in JB2005, but you're right. It does seem to work. Both the abstract base class and the concrete subclass came up in the designer without errors. -- Gillmer J. Derge [TeamB] Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> JBuilder IDE 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.