JTree set node name as one of UserObject attribute

Question

I'm using JTree to create tree view and add node to its root as following:

String nodeName = "node1";
DefaultMutableTreeNode child = new DefaultMutableTreeNode(nodeName);
root.add(child);

The UserObject for each node now has type of String. It shows "node1" as node name when display the tree.

However, I want to add UserObject to the node as an Object of the nodeObject class with 2 attributes:

private class nodeObject{
    private String nodeName;
    private boolean isSomethingElse;
    public nodeObject(String name, boolean something){
       nodeName = name;
       isSomethingElse = something;
    }
    public String getName(){
       return nodeName;
    }
    //Other setter/getter after these code
}

When I add this nodeObject to tree node:

nodeObject nodeObject = new nodeObject("node1",true);
DefaultMutableTreeNode child = new DefaultMutableTreeNode(nodeObject);
root.add(child);

It shows the object ID as node name. My question is, how i can set the node name as nodeObject.getName() so the tree can show "node1" as node name?

Any reply is much appreciated. Thank you!

Answer 1

If this object is dedicated to the JTree, and is not used anywhere else, the easiest way is to override the toString() method and return the name from this method:

@Override
public String toString() {
    return this.nodeName;
}

If you want a different toString() method, that could be used to provide more information when debugging for example, then set a custom TreeCellRenderer to the tree. This custom could just extend DefaultTreeCellRenderer, and override the following method:

@Override
public Component getTreeCellRendererComponent(JTree tree,
                                              Object value,
                                              boolean sel,
                                              boolean expanded,
                                              boolean leaf,
                                              int row,
                                              boolean hasFocus) {
    DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
    NodeObject nodeObject = (NodeObject) node.getUserObject();
    return super.getTreeCellRendererComponent(tree,
                                              nodeObject.getName(),
                                              sel,
                                              expanded,
                                              leaf,
                                              row,
                                              hasFocus);
}

EDIT:

A third solution, as mentioned by aterai in the comments, is to subclass JTree and to override the convertValueToText() method, that the default renderer calls. See http://docs.oracle.com/javase/tutorial/uiswing/components/tree.html for more details about trees.