In our scenario we have a BannerComponent. This is the Component that the Decorators need to add responsibility to.We create two (2) decorators PreBanner and PostBanner which are the relevance of where they add responsibilities.
Finally, we chain the decorators and the component being decorated.
/*
CoreLinux++
Copyright (C) 2000 CoreLinux Consortium
The CoreLinux++ Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The CoreLinux++ Library Library is distributed in the hope that it will
be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
#include <Common.hpp>
#include <BannerComponent.hpp>
#include <PreBanner.hpp>
#include <PostBanner.hpp>
using namespace corelinux;
#include <iostream>
#include <exception>
//
// In module function prototypes
//
int main( void );
//
// Functions that work with Engine types
//
void handleAssertion( AssertionCref );
void handleException( ExceptionCref );
int main( void )
{
//
// Practice gracefull exception management
//
cout << endl;
try
{
//
// Instantiate the component implementation.
// And invoke the operation.
//
BannerComponent aBanner("A Basic Banner");
cout << "-------------------------------------------" << endl;
aBanner.drawBanner( cout );
cout << endl;
cout << "-------------------------------------------" << endl;
//
// And a pre decorator and invoke the
// operation.
//
PreBanner aPreBanner("A header to ",&aBanner);
aPreBanner.drawBanner(cout);
cout << endl;
cout << "-------------------------------------------" << endl;
//
// Add a post decorator and invoke the operation
//
PostBanner aPostBanner(" with a trailer.",&aBanner);
aPostBanner.drawBanner(cout);
cout << endl;
cout << "-------------------------------------------" << endl;
//
// How you can chain decorators.
//
aPreBanner.setImplementation(&aPostBanner);
aPreBanner.drawBanner(cout);
cout << endl;
cout << "-------------------------------------------" << endl;
}
catch( AssertionRef aAssert )
{
handleAssertion(aAssert);
}
catch( ExceptionRef aException )
{
handleException(aException);
}
catch( std::exception & e )
{
cerr << e.what() << endl;
}
catch( ... )
{
cerr << "Unknown exception." << endl;
}
return 0;
}
//
// Peform default (just show it)
//
void handleAssertion( AssertionCref aAssert )
{
cerr << aAssert.getFile() << ":" << aAssert.getLine() << ":" <<
"Assertion: ";
if( aAssert.getType() == Assertion::NEVERGETHERE )
{
cerr << "NEVER_GET_HERE";
}
else
{
if( aAssert.getType() == Assertion::REQUIRE )
{
cerr << "REQUIRE";
}
else if( aAssert.getType() == Assertion::ENSURE )
{
cerr << "ENSURE";
}
else if( aAssert.getType() == Assertion::CHECK )
{
cerr << "CHECK";
}
else
{
cerr << "ASSERT";
}
cerr << "( " << aAssert.getWhy() << " )";
}
cerr << endl;
}
void handleException( ExceptionCref aExcp )
{
cerr << aExcp.getFile() << ":" << aExcp.getLine() << ":" <<
"Exception: " << aExcp.getWhy() << endl;
}
/*
Common rcs information do not modify
$Author: prudhomm $
$Revision: 1.2 $
$Date: 2000/08/31 22:49:00 $
$Locker: $
*/