如何计算JTree中的节点数？

Question

I am using JIDE's CheckBoxTree to display a nested tree of checkboxes, as in this example:

I would like to know how many nodes the tree model contains.

If I call the method tree.getModel().getChildCount(rootNode) , I only get the number of direct children (eg 12 in this case), and NOT the number of any children nested further (20+).

Answer 1

Recursively:

public int getNumberOfNodes(TreeModel model)  
{  
    return getNumberOfNodes(model, model.getRoot());  
}  

private int getNumberOfNodes(TreeModel model, Object node)  
{  
    int count = 1;
    int nChildren = model.getChildcount(node);  
    for (int i = 0; i < nChildren; i++)  
    {  
        count += getNumberOfNodes(model, model.getChild(node, i));  
    }  
    return count;  
}

Answer 2

Traverse the tree yourself using the getChild() method.

http://en.wikipedia.org/wiki/Tree_traversal