Package org.apache.tapestry5.tree

## Interface TreeExpansionModel<T>

- All Known Implementing Classes:
    `DefaultTreeExpansionModel`

      public interface TreeExpansionModel<T>

  Tracks which nodes of a `TreeModel` are currently expanded. The default implementation simply stores a set of unique node ids to identify expanded nodes. The expansion model is updated whenever folders are expanded or collapsed on the client side.
  Since:
    5.3
  See Also:
    `Tree`

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `void` | `clear()` | Marks all nodes as collapsed.
    `boolean` | `isExpanded​(TreeNode<T> node)` | Returns true if the node has been previously expanded.
    `void` | `markCollapsed​(TreeNode<T> node)` | Marks the node as collapsed (not expanded).
    `void` | `markExpanded​(TreeNode<T> node)` | Marks the node as expanded.

- - ### Method Detail

    - #### isExpanded

          boolean isExpanded​(TreeNode<T> node)

      Returns true if the node has been previously expanded.
      Parameters:
        `node` - node to check for expansion
      Returns:
        true if expanded

    - #### markExpanded

          void markExpanded​(TreeNode<T> node)

      Marks the node as expanded.

    - #### markCollapsed

          void markCollapsed​(TreeNode<T> node)

      Marks the node as collapsed (not expanded).

    - #### clear

          void clear()

      Marks all nodes as collapsed.