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An object of abstract class cannot be created

Posted on 2010-11-08
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Last Modified: 2012-06-27
hi,

when i try to compile my source code, i get this error:

"/development/demusr/osrc/hello_02/hello_02-0.0.0/libsrc/CustRegister.cxx", line 6.44: 1540-1107 (S) An object of abstract class "CustLoaderFactory" cannot be created.
"/development/demusr/include/SdkTargetFactory.h", line 44.21: 1540-1112 (I) "TargetFactory<TsfLoader>::createCondition(char *, const void *)" is a pure virtual function.
"/development/demusr/include/SdkTargetFactory.h", line 58.25: 1540-1112 (I) "TargetFactory<TsfLoader>::getTargetObj(char *, const void *)" is a pure virtual function.
"/development/demusr/include/ObjectCollector.h", line 55.23: 1540-1112 (I) "ObjectCollector<TsfLoader>::createInstance(const char *, const void *)" is a pure virtual function.
"/development/demusr/include/ObjectCollector.h", line 56.22: 1540-1112 (I) "ObjectCollector<TsfLoader>::reuseInstance(TsfLoader *, const char *, const void *)" is a pure virtual function.
"/development/demusr/osrc/hello_02/hello_02-0.0.0/libsrc/../include/CustRegistration.h", line 15.40: 1540-0202 (S) An expression of type "void *" is not allowed on the left side of "->".

Appreciate if you can advise on this with some explaination.
Thank you in advance.
header file

===========



#ifndef _CUSTLOADERFACTORY_H_

#define _CUSTLOADERFACTORY_H_



#include <TsfLoader.h>

#include <SdkTargetFactory.h>

#include <ObjectCollector.h>



class CustLoaderFactory : public TargetFactory<TsfLoader>

                                                        ,public ObjectCollector<TsfLoader>

{

    public:

        virtual int createCondition(char *condition, void *entity_type);

        virtual TsfLoader *getTargetObj(char *condition, void *entity_type);

        virtual TsfLoader *createInstance(const char *condition, void *entity_type);

        virtual int reuseInstance(TsfLoader *instance, const char *condition, void *entity_type);

};

#endif



source file

===========



#include <CustomerCard.h>

// Included all customized loader classes headers here

#include "CustLoaderFactory.h"



//entity_type is passed in as a string for now

CustLoaderFactory::createCondition(char *condition, void *entity_type)

{

    strcpy(condition, (char *)entity_type);

    return 0;

}



TsfLoader *CustLoaderFactory::getTargetObj(char *condition, void *entity_type)

{

    return getObject(condition, entity_type);

}



TsfLoader *CustLoaderFactory::createInstance(const char *condition, void *name)

{

    TsfLoader *obj = NULL;

    if (strcmp(condition, ENTITY_TYPE_CARD) == 0)

        obj = new CustomerCard();

    else

        obj = NULL;



    if ( obj )

        OTraceDebug("D-CUSTTSF-0001: Create Instance[%s]\n", condition);

    else

        OTraceError("F-CUSTTSF-0002: Unknown Object Name[%s]\n", condition);



    return obj;

}



int CustLoaderFactory::reuseInstance(TsfLoader *instance, const char *condition, void *entity_type)

{

    return 0;

}

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Question by:gagajanice
11 Comments
 
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Expert Comment

by:sedgwick
Comment Utility
can u post SdkTargetFactory.h?
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Accepted Solution

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evilrix earned 350 total points
Comment Utility
You need to implement those functions in your derived class and the function signatures MUST be identical.

The functions that need overriding are:

TargetFactory::createCondition(char *, const void *)
TargetFactory::getTargetObj(char *, const void *)
ObjectCollector::createInstance(const char *, const void *)
ObjectCollector::reuseInstance(TsfLoader *, const char *, const void *)

Since they are pure and virtual the compiler has no idea what they do until you implement them in your derived class.
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Expert Comment

by:sweetfa2
Comment Utility
You are also trying to instantiate a class of CustLoaderFactory where it is abstract.  You need to instantiate a derived class rather than the abstract class.  If you are just using a reference to a CustLoaderFactory instance in CustRegister.cxx then you don;t need to create it, you just need to refer to an existing instance.
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Expert Comment

by:evilrix
Comment Utility
>> You are also trying to instantiate a class of CustLoaderFactory where it is abstract.

It's not abstract, none of the members are pure virtual.
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LVL 17

Expert Comment

by:sweetfa2
Comment Utility
/development/demusr/osrc/hello_02/hello_02-0.0.0/libsrc/CustRegister.cxx", line 6.44: 1540-1107 (S) An object of abstract class "CustLoaderFactory" cannot be created.

>> It's not abstract, none of the members are pure virtual.


No - I guess not.
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Expert Comment

by:Xper4net
Comment Utility
Abstract status is inherited while all interfaces or pure virtual functions from base classes are not implemented.
I dont know OjectCollector.h and SdkTargetFactory.h, so I can't guess what implementation are required, but it's inside them that you'll find the solution.
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Author Closing Comment

by:gagajanice
Comment Utility
The argument type that i declared in my header file and source file is different from the OjectCollector.h and SdkTargetFactory.h. My bad for not paying enough attention to it. Thanks guys!
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Expert Comment

by:evilrix
Comment Utility
>> The argument type that i declared in my header file and source file is different from the OjectCollector.h and SdkTargetFactory.h

What aregument type do you refer? Function arguments? I explained in http:#34091062 exactly why you were getting the error. You were subclassing abstract classes so you either needed to implement the exact same functions as those that were in the base classes that were pure virtual or not sublclass abstract classes.

Can you expand on that because it doesn't explain how you fixed the issue?

Also, I don't see how the answers you've selected answer your problem.
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Expert Comment

by:evilrix
Comment Utility
#3 - http:#34091062 explained exactly what the error was and what steps needed to be taken to fix it.

No other post provided an reason for the error or a solution.
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