Third Change

SourcePro Core : Advanced Tools Module User’s Guide : PART II Advanced Tools Module Packages : Using Object Serialization : Basic Examples : Saving and Restoring an Object by Pointer : Third Change

Third Change

After adding these macros, use the new pointer-based operators to write a real_property pointer to an object stream, and then read it back. Note that the serialization factory has constructed a new real_property instance that is now owned by the module calling the input operator. The following is an example of writing a real_property pointer into a file and then reading it back again.

// examples\serial\simple\real_estate2.cpp

real_property real1("1980 Main St. Corvallis, Oregon","50x100");

real_property* real2 = 0;

{

ofstream fout(“real_estate2.dat”);

RWpostream postr(fout);

RWObjectOutputStream out = RWCompactObjectOutputStreamImp::

make(RWDataToVirtualOutputStreamImp::

make(postr)); // 1

out << &real1; // 2

}

ifstream fin("real_estate2.dat");

RWpistream pistr(fin); // 3

RWObjectInputStream in = RWCompactObjectInputStreamImp::

make(RWDataFromVirtualInputStreamImp::

make(pistr)); // 4

in >> real2; // 5

//1 Create a data stream using the standard file stream just opened and then create a compact object output stream from the data stream. The second parameter indicates the kind of object that will serve as the root element.

//2 Stream out the real_property object by reference.

//3 Open the file for input.

//4 Create a data stream and then create a compact object input stream from the data stream.

//5 Read the data back in to a fresh real_property object. The input stream allocates and constructs a new real_property object as part of the extraction process. Any address held by real2 prior to that operation is lost.