public abstract class Widget {
	public abstract void accept(Visitor v);
}

public class TextBlock extends Widget {
	public String contents;
	public int fWidth; // average width of a character
	public int fHeight; // display height of a character
	public int bWidth; // width of the display area


	/**
	 * @param contents text string contents of the block
	 * @param blockWidth pixels width for layout
	 * @param fontWidth pixels average width of the font to be used
	 * @param fontHeight pixels height of the font to be used
	 */
	public TextBlock(String contents, int blockWidth, int fontWidth, int fontHeight){
		this.contents = contents;
		fWidth = fontWidth;
		fHeight = fontHeight;
		bWidth = blockWidth;
	}
	
	public void accept(Visitor v) {
		v.visitTextBlock(this);

	}

}
import java.awt.*;

public class FillerBlock extends Widget {
	public int preferredWidth;
	public int preferredHeight;
	public Color fillColour;
	
	/**
	 * @param fillColour colour for filling
	 * @param width of block in pixels
	 * @param height of block in pixels
	 */
	public FillerBlock(Color fillColour, int width, int height){
		preferredWidth = width;
		preferredHeight = height;
		this.fillColour = fillColour; 
	}
	
	public void accept(Visitor v) {
		v.visitFillerBlock(this);
	}

}
import java.util.Vector;

public class HorizontalContainer extends Widget {
	public Vector<Widget> children;
	/*
	 * construct empty horizontal container
	 */
	public HorizontalContainer() {
			children= new Vector<Widget>();
	}
	
	/*
	 * add another child to the container
	 */
	public void add(Widget w){
		// add another widget
		children.addElement(w);
	}
	public void accept(Visitor v){
		v.visitHorizontalContainer(this);
	}
}
import java.util.Vector;

public class VerticalContainer extends Widget {
	public Vector<Widget> children;
	
	public VerticalContainer() {
			children= new Vector<Widget>();
	}
	public void add(Widget c){
	    children.addElement(c);
	}
	public void accept(Visitor v){
		v.visitVerticalContainer(this);
	}
}
import java.awt.*;

public class gowidget {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		// test operation of the protoWidgets
		// construct an example
		// bottom up
		String mainContent = "Lorem Ipsum dummy text";
		
		FillerBlock g = new FillerBlock(Color.RED,200,200);
		TextBlock a = new TextBlock("now is the time for a long story", 300,10, 10);
		FillerBlock h = new FillerBlock(Color.GREEN, 350, 100);
		VerticalContainer m = new VerticalContainer();
		m.add(g); m.add(a); m.add(h);
		
		TextBlock r = new TextBlock(mainContent, 800, 12, 14);
		HorizontalContainer k = new HorizontalContainer();
		k.add(m); k.add(r);
	
		// determine the width and height of the main frame k
		BoundingBox bbv = new BoundingBox();
		k.accept(bbv);
		System.out.println("Bounding box for the whole container is ["
				+ bbv.width + "x" + bbv.height+ "]");
		
		// report bounds of constituents
		System.out.println("---------------------------------");
		BoundingBox left = new BoundingBox();
		m.accept(left);
		System.out.println("Bounding box for the left (vertical) container is ["
				+ left.width + "x" + left.height+ "]");
		
		BoundingBox right = new BoundingBox();
		r.accept(right);
		System.out.println("Bounding box for the right textblock is ["
				+ right.width + "x" + right.height+ "]");
		
		
		
	}
}