Facade Pattern

According to Gang Of Four intent of Facade Design pattern is to Provide a unified interface to a set of interfaces in a subsystem. Facade defines a higher-level interface that makes the subsystem easier to use.

SAMPLE CODE:

#include <iostream>

using namespace std;

class PreprocessorSystem {
public:
    void doPreprocess()
    {
        cout << "--->Program In Preprocessing Stage" << endl;
    }
};

class CompilerSystem {
public:
    void doCompile()
    {
        cout << "--->Program In Compile Stage" << endl;
    }
};

class AssemblerSystem {
public:
    void doAssembly()
    {
        cout << "--->Program in Assembling Stage" << endl;
    }
};

class LinkerSystem {
public:
    void doLinking()
    {
        cout << "--->Program In Linking Stage" << endl;
    }
};

class CompilerFacade {
private:
    PreprocessorSystem  preprocessor;
    CompilerSystem      compiler;
    AssemblerSystem     assembler;
    LinkerSystem        linker;

public:
    void Compile(string programName)
    {
        cout << programName << " Compliation Started" << endl;
        preprocessor.doPreprocess();
        compiler.doCompile();
        assembler.doAssembly();
        linker.doLinking();
        cout << programName << " Compilation Finished" << endl;
    }
};

int main()
{
    CompilerFacade clientCompiler;
    clientCompiler.Compile("MYPROGRAM.cpp");

    return 0;
}   

OUTPUT:

MYPROGRAM.cpp Compliation Started
--->Program In Preprocessing Stage
--->Program In Compile Stage
--->Program in Assembling Stage
--->Program In Linking Stage
MYPROGRAM.cpp Compilation Finished

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