@Override
public ConnectionAnchor getTargetConnectionAnchor(
        ConnectionEditPart connEditPart) {
    return getConnectionAnchor();
}

@Override
public ConnectionAnchor getSourceConnectionAnchor(
        ConnectionEditPart connEditPart) {
    return getConnectionAnchor();
}

private ConnectionAnchor connectionAnchor;

protected ConnectionAnchor getConnectionAnchor() {
    if (connectionAnchor== null) {
        connectionAnchor= new FixedConnectionAnchor(getNodeFigure());
    }
    return connectionAnchor;
}

class FixedConnectionAnchor extends SlidableAnchor {

    public FixedConnectionAnchor(IFigure owner) {
        super(owner);
    }

    @Override
    protected Point getLocation(Point ownReference, Point foreignReference) {
        Rectangle bounds = getOwner().getBounds();
        Dimension diff = foreignReference.getDifference(bounds.getCenter());
        Point p;
        if(Math.abs(diff.width) > Math.abs(diff.height)) {
            p = diff.width > 0 ? bounds.getRight() : bounds.getLeft();
        }
        else {
            p = diff.height > 0 ? bounds.getBottom() : bounds.getTop();
        }
        PrecisionPoint pp = new PrecisionPoint(p);
        getOwner().translateToAbsolute(pp);
        return pp;
    }
}