echopointng.tree
Interface TreeModel

All Known Subinterfaces:

TreeTableModel

All Known Implementing Classes:

AbstractTreeTableModel, DefaultTreeModel, DefaultTreeTableModel

public interface TreeModel

The TreeModel interface defines a suitable data model for a Tree.

There is an implied behavioural contract between a Tree and its TreeModel. The Tree gaurantees not to call any of the getChildXXX() methods until they are absolutely needed (for example a parent node is expanded).

This is to allow children to be lazily created "as needed". Ths is useful for very large TreeModels or ones where child node creation is an expensive operation

Note that the isLeaf() may be called at any time and if it returns true, then the node cannot contain any child nodes. However the inverse if not necessarily true. A model may return that a node is NOT a leaf but it may still have zero child nodes.

Method Summary

void	addTreeModelListener(TreeModelListener l) Adds a listener for the TreeModelEvent posted after the tree changes.
Object	getChild(Object parent, int index) Returns the child of parent at index index in the parent's child array.
int	getChildCount(Object parent) Returns the number of children of parent.
int	getIndexOfChild(Object parent, Object child) Returns the index of child in parent.
Object	getNodeById(String id)
String	getNodeId(Object node) Returns an identifier for a node.
Object	getRoot() Returns the root of the tree.
boolean	isLeaf(Object node) Returns true if node is a leaf.
void	removeTreeModelListener(TreeModelListener l) Removes a listener previously added with addTreeModelListener().
void	valueForPathChanged(TreePath path, Object newValue) Messaged when the user has altered the value for the item identified by path to newValue.

Method Detail

addTreeModelListener

void addTreeModelListener(TreeModelListener l)

Adds a listener for the TreeModelEvent posted after the tree changes.

Parameters:

l - the listener to add

getChild

Object getChild(Object parent,
                int index)

Returns the child of parent at index index in the parent's child array. parent must be a node previously obtained from this data source. This should not return null if index is a valid index for parent (that is index >= 0 && index < getChildCount(parent)).

Parameters:

parent - a node in the tree, obtained from this data source

Returns:

the child of parent at index index

getChildCount

int getChildCount(Object parent)

Returns the number of children of parent. Returns 0 if the node is a leaf or if it has no children. parent must be a node previously obtained from this data source.

Parameters:

parent - a node in the tree, obtained from this data source

Returns:

the number of children of the node parent

getIndexOfChild

int getIndexOfChild(Object parent,
                    Object child)

Returns the index of child in parent.

getRoot

Object getRoot()

Returns the root of the tree. Returns null only if the tree has no nodes.

Returns:

the root of the tree

isLeaf

boolean isLeaf(Object node)

Returns true if node is a leaf. It is possible for this method to return false even if node has no children. A directory in a filesystem, for example, may contain no files; the node representing the directory is not a leaf, but it also has no children.

Parameters:

node - a node in the tree, obtained from this data source

Returns:

true if node is a leaf

removeTreeModelListener

void removeTreeModelListener(TreeModelListener l)

Removes a listener previously added with addTreeModelListener().

valueForPathChanged

void valueForPathChanged(TreePath path,
                         Object newValue)

Messaged when the user has altered the value for the item identified by path to newValue. If newValue signifies a truly new value the model should post a treeNodesChanged event.

Parameters:

path - path to the node that the user has altered.

newValue - the new value from the Tree.

getNodeId

String getNodeId(Object node)

Returns an identifier for a node. The identifier should be assigned to the Node when added to the model and thereafter it should not change.

Returns:

String - a unique identifier for a specific node

getNodeById

Object getNodeById(String id)

Returns:

a node Object based on its unique identifier (obtained using getNodeId)