RTTI in Java using getClass() and instanceof

//======================================================================
// CShape.java
// Purpose: Class file defining a base class for this RTTI demonstration.
// Author: Dr. Rick Coleman
//======================================================================

public class CShape
{
	/** Shape type */
	protected int m_iType;
	
	/** Class name */
	protected String m_sTypeName;
	
	public static final int SHAPE 		= 0;
	public static final int RECTANGLE 	= 1;
	public static final int OVAL 		= 2;
	public static final int LINE 		= 3;
	public static final int POLYGON 	= 4;
	
	//----------------------------------------------
	/** Default constructor */
	//----------------------------------------------
	public CShape()
	{
		m_iType = SHAPE;
		m_sTypeName = "CShape";
	}
	
	//----------------------------------------------
	/** Get the type */
	//----------------------------------------------
	public int getType()
	{
		return m_iType;
	}
	
	//----------------------------------------------
	/** Get the class name */
	//----------------------------------------------
	public String getTypeName()
	{
		return m_sTypeName;
	}
}

//===========================================================================
// CRectangle.java
// Purpose: Class file defining a derived class for this RTTI demonstration.
// Author: Dr. Rick Coleman
//===========================================================================

public class CRectangle extends CShape
{

	//----------------------------------------------
	/** Default constructor */
	//----------------------------------------------
	public CRectangle()
	{
		m_iType = RECTANGLE;
		m_sTypeName = "CRectangle";
	}
}

//===========================================================================
// COval.java
// Purpose: Class file defining a derived class for this RTTI demonstration.
// Author: Dr. Rick Coleman
//===========================================================================

public class COval extends CShape
{

	//----------------------------------------------
	/** Default constructor */
	//----------------------------------------------
	public COval()
	{
		m_iType = OVAL;
		m_sTypeName = "COval";
	}
}

//===========================================================================
// CLine.java
// Purpose: Class file defining a derived class for this RTTI demonstration.
// Author: Dr. Rick Coleman
//===========================================================================

public class CLine extends CShape
{

	//----------------------------------------------
	/** Default constructor */
	//----------------------------------------------
	public CLine()
	{
		m_iType = LINE;
		m_sTypeName = "CLine";
	}
}

//===========================================================================
// CPolygon.java
// Purpose: Class file defining a derived class for this RTTI demonstration.
// Author: Dr. Rick Coleman
//===========================================================================

public class CPolygon extends CShape
{

	//----------------------------------------------
	/** Default constructor */
	//----------------------------------------------
	public CPolygon()
	{
		m_iType = POLYGON;
		m_sTypeName = "CPolygon";
	}
}

import java.util.Vector;

//======================================================================
// RTTI_DemoMain.java
// Purpose: This is a demonstration of Run Time Type Identification 
//		in Java using the instanceof operator.
// Author: Dr. Rick Coleman
//======================================================================
public class RTTI_DemoMain
{
	private Vector sVec;
	
	//-----------------------------------------------
	/** Default constructor */
	//-----------------------------------------------
	public RTTI_DemoMain()
	{
		sVec = new Vector();
		
		// Create some shapes and add to the vector
		sVec.add(new CRectangle());
		sVec.add(new COval());
		sVec.add(new CLine());
		sVec.add(new CPolygon());
		
		// See what we have
		for(int i=0; i<sVec.size(); i++)
		{
			CShape s = (CShape)sVec.elementAt(i);
			System.out.println("Type = " + s.getType() + ", Class = " + s.getTypeName() +
					" (from calling functions inherited from CShape)");
			System.out.println("Class = " + s.getClass() + 
					" (from calling the getClass() function)");
			if(s instanceof CRectangle)
			{
				System.out.println("\tinstanceof recognizes a CRectangle instance.");
			}
			else if(s instanceof COval)
			{
				System.out.println("\tinstanceof recognizes a COval instance.");
			}
			else if(s instanceof CLine)
			{
				System.out.println("\tinstanceof recognizes a CLine instance.");
			}
			else if(s instanceof CPolygon)
			{
				System.out.println("\tinstanceof recognizes a CPolygon instance.");
			}
			if(s instanceof CShape)
			{
				System.out.println("\tinstanceof also recognizes a CShape instance.");
			}
		}
	}
	
	public static void main(String[] args)
	{
		RTTI_DemoMain rDemo = new RTTI_DemoMain();
	}
}