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

#ifndef _iterator_h
#define _iterator_h

/**
 * forward declarations
 */

class Iterator;
class ConcreteIterator;
class ConcreteAggregate;


/**
 * Defines an interface for creating an Iterator object.
 */

class Aggregate
{

public:
	Aggregate();
	virtual Iterator* createIterator() = 0;

};

/**
 * Defines an interface for accessing and traversing elements.
 */

class Iterator
{

public:
	virtual int first() = 0;
	virtual int next() = 0;
	virtual int isDone() = 0;
	virtual int currentItem() = 0;

};

/**
 * Implements the Iterator creation interface to return an instance
 * of the proper ConcreteIterator.
 */

class ConcreteAggregate: public Aggregate
{

public:

	/**
	 * Simple data structure to traverse.
	 */

	int storage[ 1000 ];

	/**
	 * Return the proper iterator for
	 * this type of aggregate.
	 */

	virtual Iterator* createIterator();
};

/**
 * Implements the Iterator interface. Keeps track of the current
 * position in the traversal of the aggregate.
 */

class ConcreteIterator: public Iterator
{

private:
	int current;
	ConcreteAggregate* root;

public:
	ConcreteIterator( ConcreteAggregate* root );
	virtual int first();
	virtual int next();
	virtual int isDone();
	virtual int currentItem();

};

#endif