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The <o:tree> allows the developers to have full control over the markup of a tree hierarchy by declaring the appropriate Faces components or HTML elements in the markup. The <o:tree> does namely not render any HTML markup by itself.

The component value must point to a tree of data objects represented by a TreeModel instance, typically established via a ValueExpression. During iterative processing over the nodes of tree in the tree model, the object for the current node is exposed as a request attribute under the key specified by the var attribute. The node itself is exposed as a request attribute under the key specified by the varNode attribute.

The <o:tree> tag supports only child tags of type <o:treeNode>, representing parent tree nodes. There can be multiple <o:treeNode> tags, each representing a separate parent tree node level, so that different markup could be declared for each tree node level, if necessary. The <o:treeNode> tag in turn supports child tag <o:treeNodeItem> which represents each child of the current parent tree node. The <o:treeNodeItem> in turn supports child tag <o:treeInsertChildren> which represents the insertion point of the grand children.

Here is a basic usage example where each parent tree node level is treated the same way via a single <o:treeNode>:

 <o:tree value="#{bean.treeModel}" var="item" varNode="node">
     <o:treeNode>
         <ul>
             <o:treeNodeItem>
                 <li>
                     #{node.index} #{item.someProperty}
                     <o:treeInsertChildren />
                 </li>
             </o:treeNodeItem>
         </ul>
     </o:treeNode>
 </o:tree>
 

treeNode

The <o:treeNode> represents the parent tree node. Within this component, the var attribute of the <o:tree> will expose the parent tree node. Each of its children is processed by <o:treeNodeItem> on which the var attribute of the <o:tree> in turn exposes each child of the parent tree node.

The optional level attribute can be used to specify for which tree node level as obtained by TreeModel#getLevel() the <o:treeNode> should be rendered. The root tree node has level 0. If the level attribute is unspecified, then the <o:treeNode> will be rendered for any tree node level which hasn't already a <o:treeNode level="x"> specified.

treeNodeItem

The <o:treeNodeItem> represents the child item of the parent tree note as represented by <o:treeNode>. Within this component, the var attribute of the parent <o:tree> component will expose the child tree node.

Within <o:treeNodeItem> you can use <o:treeInsertChildren> to declare the place where to recursively render the <o:treeNode> whereby the current child item is in turn interpreted as a parent tree node (i.e. where you'd like to insert the grand-children).

treeInsertChildren

The <o:treeInsertChildren> represents the insertion point for the grand children. This is in turn further interpreted as <o:treeNode>.