View source for A Binary Tree Node Example

'''The Binary Tree Node Example'''

In this tutorial, we present an example of binary tree node. The Binary Tree node has the following structure

     class bt {
        boolean travel ;
        btnode left;
        btnode right;
     };

and we want to visualize its object as

[[File:Binarytree.jpg]]

Good luck and let's rock !



# Open the Examples/java<nowiki>/bt.ja</nowiki>va
# set break points at line 59
# run the debuggee
# visualize&nbsp;'''"root"'''
# When mapping dialog pops up for the root, input the mapping below. In this mapping, we use a ball_laser to visualize root. Since we want the variable name to appear on the ball, so we link the variable to port&nbsp;'''varname'''

[[File:bt-root.jpg]]

# Click on the ball
# When mapping dialog pops up for the bt, the goal of the visualization is
* let a ball represent the&nbsp;'''travel'''. In addition, let true/false be visualized by the colors red/black to gain the advantages of visualization.
* pointers&nbsp;'''left'''&nbsp;and&nbsp;'''right'''&nbsp;are also visualized as smaller balls but they are supposed to locate themselves at the southwest and southeast corners of&nbsp;'''travel'''&nbsp;and have a laser to mimic the directed arcs in textbooks. So, to complete this visualization goal, the following mappings is the final objective.

[[File:BigbintreeMDS.jpg]]

Let's complete the mapping step by step.

# Create the Red/Black ball
## Place a Math mapping node (select tab "arith" in the left subwindow)
## link&nbsp;'''travel'''&nbsp;to the mapping node.
## Right click the math node -&gt; select "key in the formula"
## enter "$0*1.0" This formula transform a boolean variables to a floating point variable. The variables connected to the Math node can be accessed at $0,$1,$2... in the formula
## Place a Sphere_UBVM mapping node
## Right Click at the node-&gt; select "Set Node Attributes"
## Click on&nbsp;'''"COLOR"'''&nbsp;to makes color attributes (RGB) of Sphere_UBVM visible.
## link the OUT port of the Math node to port _vm_r (the Red color)
# Create the ball laser for pointer&nbsp;'''left'''
## Select tab "Composite"
## click "ball_laser"
## link&nbsp;'''left'''&nbsp;to port&nbsp;''varname''&nbsp;and&nbsp;''wop''
## Right click the "ball_laser" -&gt; select "Set Node Attributes" to pop up the following dialog
## Select port&nbsp;''_vm_rx''
## Click "edit attributes" -&gt; enter&nbsp;'''-50'''
## Select port&nbsp;''_vm_ry''
## Click "edit attributes" -&gt; enter value&nbsp;'''-50'''
## press OK

[[File:Attribute_Dialog.jpg]]

The above setting is to place the ball_laser at a relative position of (-50,-50,0) which will be the southwest corner of Red/Black ball.

Please follow the above steps to set up pointer "right" except the relative position is (50,-50,0)

# Add a "vmcollector" at the tab of "basic" - the role of vmcollector is explained in&nbsp;collectors?
# Add a "Container_ubvm" at the tab of "ubvm" - what is the purpose of containers is explained in&nbsp;containers?
# Complete all the links
# Press&nbsp;'''"APPLY ALL"'''&nbsp;. This step is important to tell xDIVA that this mapping is automatically applied to any future object whose type is bt.&nbsp;'''If you forget to do so, you will need to redo the mappings!'''
# Press OK.

Good Job! You will have a visualization. Try to click the left and right pointers and see what happens.