Re: oop programming

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so it will be somthing like :


ifPrinter printerObj = PrinterFactory.getPrinterObject("EpsonP333");
printDocument.setDocument(d1);
printerObj.printDocument();


class PrinterFactory{

public IfPrinter getPrinterObject(string printerName){
if(printerName.equels("Hpv40")
return new Hpv40();
else if(printerName.equels("EpsonP333")
return new EpsonP333();

.....
}

}


interface IfPrinter
{
void printDocument();

void rollEmptyPage();

void cleanPrinterHead();
string getPrinterType();

}



class Hpv40 : IfPrinter

{
public void printDocument(){

do Hpv40 printing ...

}

public string getPrinterType(){ return this.type;}
}

class EpsonP333 : IfPrinter

{
public void printDocument(){

do EpsonP333 printing ...

}

public string getPrinterType(){ return this.type;}

}

class Cannon512: IfPrinter

{
public void printDocument(){

do Cannon512 printing ...

}

public string getPrinterType(){ return this.type;}

}











"Reginald Blue" <Reginald_Blue@xxxxxxxxxxx> wrote in message
news:da4gcu$nlq$1@xxxxxxxxxxxxxxxxxxxxxx
> Sharon wrote:
>> "wozza" <wozza96@xxxxxxxxxxxxxxxxxx> wrote in message
>> news:42c5ab87$0$9732$afc38c87@xxxxxxxxxxxxxxxxxxxxxxx
>>> "Sharon" <Sharon669@xxxxxxxxxxx> wrote in message
>>> news:evGnEznfFHA.3916@xxxxxxxxxxxxxxxxxxxxxxx
>>>> I have a logical oop problem; I have an interface, and derived
>>>> classes
>>>>
>>>> The interface represents a general printer, and each class is a
>>>> specific printer
>>>>
>>>>
>>>>
>>>> The question is what is the correct way to get a new instance of a
>>>> printer by its name?
>>>>
>>>> Where should the getPrinterObject function be?
>>>>
>>>
>>> You have a separate PrinterFactory object that can return a
>>> reference to the correct type.
>>
>> shuld i add new PrinterFactory class ?
>
> Yes.
>
>> how do i implement it ?
>
> Depends on what you're trying to accomplish in the long term. Generally,
> you'd have the factory look up the right thing to instantiate, but look up
> from where is the main question. Perhaps just a case statement. But
> maybe
> you want something more dynamic, so you could have it load a new assembly
> from disk.
>
> So, generally, it's:
>
> 1. Receive request for creation of specific type.
> 2. Find specific type.
> 3. Create new instance of specific type.
> 4. Return new instance (via interface).
> --
> Reginald Blue
> "I have always wished that my computer would be as easy to use as my
> telephone. My wish has come true. I no longer know how to use my
> telephone."
> - Bjarne Stroustrup (originator of C++) [quoted at the 2003
> International Conference on Intelligent User Interfaces]
>
>


"Reginald Blue" <Reginald_Blue@xxxxxxxxxxx> wrote in message
news:da4gcu$nlq$1@xxxxxxxxxxxxxxxxxxxxxx
> Sharon wrote:
>> "wozza" <wozza96@xxxxxxxxxxxxxxxxxx> wrote in message
>> news:42c5ab87$0$9732$afc38c87@xxxxxxxxxxxxxxxxxxxxxxx
>>> "Sharon" <Sharon669@xxxxxxxxxxx> wrote in message
>>> news:evGnEznfFHA.3916@xxxxxxxxxxxxxxxxxxxxxxx
>>>> I have a logical oop problem; I have an interface, and derived
>>>> classes
>>>>
>>>> The interface represents a general printer, and each class is a
>>>> specific printer
>>>>
>>>>
>>>>
>>>> The question is what is the correct way to get a new instance of a
>>>> printer by its name?
>>>>
>>>> Where should the getPrinterObject function be?
>>>>
>>>
>>> You have a separate PrinterFactory object that can return a
>>> reference to the correct type.
>>
>> shuld i add new PrinterFactory class ?
>
> Yes.
>
>> how do i implement it ?
>
> Depends on what you're trying to accomplish in the long term. Generally,
> you'd have the factory look up the right thing to instantiate, but look up
> from where is the main question. Perhaps just a case statement. But
> maybe
> you want something more dynamic, so you could have it load a new assembly
> from disk.
>
> So, generally, it's:
>
> 1. Receive request for creation of specific type.
> 2. Find specific type.
> 3. Create new instance of specific type.
> 4. Return new instance (via interface).
> --
> Reginald Blue
> "I have always wished that my computer would be as easy to use as my
> telephone. My wish has come true. I no longer know how to use my
> telephone."
> - Bjarne Stroustrup (originator of C++) [quoted at the 2003
> International Conference on Intelligent User Interfaces]
>
>


.

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