A tree populated with content from a com.webmethods.caf.faces.data.tree.ITreeContentProvider object. An ITreeContentProvider presents a flattened view of the tree, iterating over the tree structure in depth-first order. The Async Tree control differs from the standard Tree control in that the Async Tree control initially displays only a small portion of the tree and uses asynchronous requests to display other portions as a user expands nodes on the client.

LazyNodeTreeContentProvider

For large trees, use the LazyNodeTreeContentProvider, which is designed to access a tree's nodes only as needed, making it suitable for use with a data source that would normally require many queries to construct the full tree.

To use the LazyNodeTreeContentProvider, you must:

• Expose your data as a tree of com.webmethods.caf.faces.data.tree.INode objects.
• Configure your INode implementation to call the getChildren() method to confirm whether the node has children or not. If the node has children, a "+" icon is added to the node in the user interface. Lazy loading is still applied, as the method does not work recursively down the tree.

If the node has children, they are loaded when the user expands the node in the user interface. As a result, only a relatively small number of the tree nodes must load their children in a large data tree.

You can initialize the LazyNodeTreeContentProvider with a list of root nodes or with a single root node. You can configure the initial state of the LazyNodeTreeContentProvider to a certain depth by using its setOpenToDepth() method, where 0 indicates completely closed, 1 indicates show children, 2 indicates show children and grandchildren. For example:

INode root = new MyNodeImpl("my root info");
ITreeContentProvider tree = new LazyNodeTreeContentProvider(root);
tree.setOpenToDepth(1);


Columns and Rows

Just like the Table control, columns can be added to the Tree control to display content for each tree row. Table columns (including special columns, like Select Row columns) work in Trees exactly the same as they do in Tables. Additionally, special tree-specific Tree Toggle column controls enable users to expand and collapse tree rows. It is recommended that each tree include a Tree Toggle control.

You can sort columns by specifying a key in the column's sort property value. For more information, see the Standard Column control.

Asynchronous Properties

Use the Async Tree control's initialDepth, progressDelay, progressFlashOnComplete, progressMsg, refillDepth, refreshOnShow, and suppressInputs attributes to customize the tree's asynchronous behavior.

• Use the initialDepth property to set the number of tree nodes loaded the first time on the client.

  When specifying the initialDepth attribute, use 0 to indicate roots only; 1 to indicate roots and children; 2 to indicate roots, children and grandchildren, etc.

• Use the refillDepth property to determine how many levels of nodes are loaded when the user tries to expand a node, and the node's children are not available on the client.

  When specifying the refillDepth attribute, use 0 to indicate children only; 1 to indicate children and grandchildren; 2 to indicate children, grandchildren, and great grandchildren, etc.

Children

javax.faces.Column, Basic Column control