Declaring the Basic Classes

SourcePro Core : XML Streams Module User’s Guide : A Simple XML Streams Use Case : Examining the Code : Declaring the Basic Classes

The code below shows the base class real_property and its two derived classes residential and rural_land. It is based on the example code in the \examples\xmlstreams\real_estate directory.

Here is the declaration for the base class real_property:

class real_property

{

public:

real_property() {} // 1

real_property(const RWCString& address,

const RWCString& size)

: address_(address), size_(size)

{}

virtual ~real_property() {} // 2

bool operator== (const real_property& prop) const {

return address_ == prop.address_;

}

private:

RWCString address_;

RWCString size_;

};

//1 This is the explicit default constructor required in serializable classes.

//2 At least one virtual function is needed, because the by-reference streaming facility relies on RTTI, and that requires a v-table.

Here are the declarations for the two derived classes residential and rural_land:

class residential : public real_property

{

public:

residential() // 1

{}

residential(const RWCString& address, const RWCString& size,

long footage)

: real_property(address, size),

footage_(footage)

{}

bool operator== (const residential& prop) const {

return real_property::operator==(prop);

}

private:

long footage_; //Square footage of the house

};

class rural_land : public real_property

{

public:

rural_land()

{}

rural_land(const RWCString& address, const RWCString& size,

double irrigation = 0.0)

: real_property(address, size), irrigation_(irrigation)

{}

bool operator== (const rural_land& prop) const {

return real_property::operator==(prop);

}

private:

double irrigation_; //Irrigation acres for the property

};

//1 The derived classes also require an explicit default constructor.

Note that the derived classes residential and rural_land inherit a virtual function from the base class and therefore fulfill the requirement for serializable classes.