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From: Robert Martin on 2 Apr 2008 23:54
On 2008-03-19 11:25:47 -0500, ManicQin <ManicQin(a)gmail.com> said:

> Hi, consider the next fundamental class hierarchy
>
> parseData recieves an array of chars and resolves the data into
> commands.
> Every device has it's own parseData function (fundamental)
>
> class baseDevice
> {
> public:
> virtual int parseData(BYTE* bData) = 0;
> };
>
> class deviceA : public baseDevice
> {
> public:
> int parseData(BYTE* bData)
> { return 0; }
> }
>
> class deviceB : public baseDevice
> {
> public:
> int parseData(BYTE* bData)
> { return 1; }
> }
>
> You got the point... (Keep in mind that every device has more than one
> function)
> Now lets say I'm building a separated logger that logs all
> communication and prints the RAW data. And I want the logger to be
> able to parse the communication into the commands according to the
> device's specific parser. I would'nt want to give the parser the
> entire device class only the parsing ability...
> I thought about encapsulating the parsing logic into a functor and the
> logger could just instantiate the parser he needs..
>
> 1) Are there any Pit falls in the solution?
> 2) Is there any better way to solve this problem?

The logger asks the device for the parser:

class baseDevice
{
public:
virtual int parseData(BYTE* bData) = 0;
virtual Parser* getParser() const = 0;
};

The logger then parses the data with that particular parser. The
parser probably has a toString method or a generateLogString command or
something like that. Each parser returns a loggable string.

class Logger
{
public void logCommand(baseDevice* device, BYTE* bData) {
//forgive the inline function
Parser* p = device->getParser();
string message = p.generateLogString(bData);
logMessage(message);
}
};


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