/**
 * flyweight.h
 * Implemented by Blueprint Technologies, Inc.
 */

#ifndef _flyweight_h
#define _flyweight_h

#include <vector>
#include <utility>
#include <string>
using namespace std;

/**
 * Abstract data type for the pattern.
 */

class ExtrinsicState
{
};

/**
 * Declares an interface through which flyweights can receive
 * and act on extrinsic state.
 */

class Flyweight
{

public:
	virtual void operation( ExtrinsicState* state ) = 0;

};

/**
 * Implements the Flyweight interface and adds storage for intrinsic
 * state, if any. A ConcreteFlyweight object must be sharable. Any state
 * it stores must be intrinsic; that is, it must be independent of the
 * ConcreteFlyweight object's context.
 */

class ConcreteFlyweight: public Flyweight
{
	
public:
	virtual void operation( ExtrinsicState* state )
	{
	};

};

/**
 * Not all Flyweight subclasses need to be shared. The Flyweight interface
 * enables sharing; it doesn't enforce it. It's common for UnsharedConcreteFlyweight
 * objects to have ConcreteFlyweight objects as children at some level
 * in the flyweight object structure (as the Row and Column classes have).
 */

class UnsharedConcreteFlyweight: public Flyweight
{

public:
	virtual void operation( ExtrinsicState* state )
	{
	};

};

/**
 * Creates and manages flyweight objects. Ensures that flyweights are shared
 * properly. When a client requests a flyweight, the FlyweightFactory
 * object supplies an existing instance or creates one, if none exists.
 */

typedef pair< string, Flyweight* > FlyweightPair;

class FlyweightFactory
{

private:
	vector< FlyweightPair > flyweights;

public:
	Flyweight* getFlyweight( string key )
	{
		vector< FlyweightPair >::iterator i;
		int found = 1;
		for( i = flyweights.begin(); i != flyweights.end(); ++i )
		{
			FlyweightPair fp = *i;
			if( fp.first == key )
			{
				return fp.second;
			}
		}
		FlyweightPair fp;
		fp.first = key;
		fp.second = new ConcreteFlyweight();
		flyweights.push_back( fp );
		return fp.second;
	};

};

#endif