Draw a bi-directional link in JViews

Question

How to draw a bi-directional link?

Answer

Since JViews 6.0, IlvEnhancedPolylineLinkImage supports bi-directional link display, that is, it can show two arrow heads.

Alternatively, you can override the draw method in IlvLinkImage to draw the additional arrow.

IlvBidirectionalLink.java

import java.awt.Graphics;
import ilog.views.IlvGraphic;
import ilog.views.IlvLinkImage;
import ilog.views.IlvPoint;
import ilog.views.IlvRect;
import ilog.views.IlvTransformer;
/**
* Simple IlvLinkImage subclass to include the drawing of a second
* arrow.
*/
public class IlvBidirectionalLink extends IlvLinkImage {
public IlvBidirectionalLink(IlvGraphic from, IlvGraphic to)  {
super(from,to,true);
}
/**
* Draws a link with two arrows on each end.
*/
public void draw(Graphics dst, IlvTransformer t)  {
// Draw common link.
super.draw(dst, t);
// Add another arrow.
IlvPoint[] points = getLinkPoints(t);
IlvPoint from = points[0];
IlvPoint to = points[1];
dst.setColor(getForeground());
drawArrow(dst, to, from, t);
}
/**
* Adds the bbox of the additional arrow to the original
*
*/
public IlvRect boundingBox (IlvTransformer t)  {
IlvRect rect = super.boundingBox(t);
IlvPoint[] points = getLinkPoints(t);
IlvPoint from = points[0];
IlvPoint to = points[1];
IlvRect secondArrowBBox = this.arrowBBox(to, from, t);
rect.add(secondArrowBBox);
return rect;
}
}