How To Traverse ADF Tree

If you are thinking how to delete nodes from ADF tree, there is Frank Nimphius blog post - ADF Faces RC: Single row / Multi row delete from a tree component. However, Frank says that his blog entry is still a raw diamond and needs some polishing. In his example, if you remove root node, all child nodes still will remain in database. This means tree hierarchy will be broken. I decided to polish raw diamond, to describe how you can traverse ADF tree and remove all selected nodes together with children.

Download sample application - TreeTraversal.zip. This sample implements ADF tree traversal algorithm without recursion. ADF tree component provides Java API to get parent node for current node, this allows to avoid recursion.

I have defined tree binding and created action listener method, where tree traversal code is implemented:

Tree traversal algorithm scans selected nodes, and walks through all child nodes. When it reaches last child in tree branch, it returns back until it finds next child sibling. At the end it will return to the initial node, where tree traversal was started - root node.

I'm using two helper methods, one to get first child and second to get next sibling. Its ADF tree Java API, nothing special:

Let's see how it works. We can select multiple nodes, children of all those selected nodes will be traversed:

I intentionally commented node.getRow().remove; in my sample, just to prevent you from all nodes deletion by mistake :-) Traversed nodes are reported in the log:

It starts from first selection and walks from 100 to 102, reports parent node 90 and goes to second selection, walks through and reports parent node 110.

You can select such node, which contains multiple branches:

Tree traversal will work as well - it will enter first branch, traverse it and move to next sibling branch. Whole report for previous selection:

If you are planning to traverse large tree branches, you should increase ADF tree RangeSize property value. Default value is 25, means it will keep only 25 nodes in memory, so you will not be able to traverse whole hierarchy. With default RangeSize it will render large tree hierarchy structures pretty slow, I recommend to increase it to something at least 500:

It will keep 500 nodes in memory, and will allow such tree operations as Expand All Nodes and Expand All Nodes Below to perform faster.