Best way of creating an XML node from an object

[xtal256]

Yeah, i was thinking of that too. It would mean that serializable classes would need 3 such methods instead of just 1, but it seems like the only other way.
Besides, my subclasses do not need specific element names or attributes, so i do not need to override the open and close tag methods for them.

thanks for your help.

[wysota]

Besides, my subclasses do not need specific element names or attributes, so i do not need to override the open and close tag methods for them.

They don't need it now but they might need it in two weeks or seven months from now (like if you need to introduce versioning). Better safe than sorry.

If you want something simpler, you can always do this:

class Object {
public:
    void serialize(QXmlStreamWriter &writer) {
        writer.writeStartElement(name());
        writeContents(writer);
        writer.writeEndElement();
    }
protected:
    virtual QString name() const { return "Object"; }
    virtual void writeContents(QXmlStreamWriter &writer) {}
};
 
class SubObject : public Object {
protected:
    QString name() const { return "SubObject"; }
    void writeContents(QXmlStreamWriter &writer) {
        Object::writeContents(writer);
        writer....
    }
};

class Object {
public:
    void serialize(QXmlStreamWriter &writer) {
        writer.writeStartElement(name());
        writeContents(writer);
        writer.writeEndElement();
    }
protected:
    virtual QString name() const { return "Object"; }
    virtual void writeContents(QXmlStreamWriter &writer) {}
};

class SubObject : public Object {
protected:
    QString name() const { return "SubObject"; }
    void writeContents(QXmlStreamWriter &writer) {
        Object::writeContents(writer);
        writer....
    }
};

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[xtal256]

Besides, my subclasses do not need specific element names or attributes, so i do not need to override the open and close tag methods for them.

They don't need it now but they might need it in two weeks or seven months from now (like if you need to introduce versioning). Better safe than sorry.

Yeah, but i can always add it then. It's just a matter of how much functionality i want right now. If i ever need to make subclasses use their own element name or add attributes, then i can quite simply override the open and close tag methods.

[wysota]

Yeah, but i can always add it then. It's just a matter of how much functionality i want right now. If i ever need to make subclasses use their own element name or add attributes, then i can quite simply override the open and close tag methods.

I guess you're not used to working in a team... Happy you

[xtal256]

Actually, that is probably what most teams would do
Besides, this is a personal project i am working on, so i can do whatever i want.

[wysota]

Actually, that is probably what most teams would do

Where I work I have to think two steps ahead. Since most of what I do there is meant to be ready for "two weeks ago", before even the code is stable it is already being used by others who sometimes abuse it and changing my API (or just the code logic) without breaking their code is hard, so I have to first think how they might abuse my code tomorrow and then how to make sure them doing that will not break the code I will be writing next week. I'd certainly go for three methods in this case if I had to do it the way you do it. Well... I wouldn't do it like that but that's another thing. I'd probably either subclass QXmlStreamWriter or write a set of overloaded standalone functions for serialization just like QDataStream does. Especially that with XML you can implement inheritance by using subnodes which is much more readable.

<SubObject>
    <parent>
        <Object>
        <!-- ... -->
        </Object>
    </parent>
    <attributes>
    <!-- ... -->
    </attributes>
</SubObject>

<SubObject>
    <parent>
        <Object>
        <!-- ... -->
        </Object>
    </parent>
    <attributes>
    <!-- ... -->
    </attributes>
</SubObject>

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On a side note, this is also how ECMAScript implements "inheritance" - by using prototypes.