Class TreePath

java.lang.Object
- javax.swing.tree.TreePath

All Implemented Interfaces:: Serializable

public class TreePath
extends Object
implements Serializable

TreePath represents an array of objects that uniquely identify the path to a node in a tree. The elements of the array are ordered with the root as the first element of the array. For example, a file on the file system is uniquely identified based on the array of parent directories and the name of the file. The path /tmp/foo/bar could be represented by a TreePath as new TreePath(new Object[] {"tmp", "foo", "bar"}).

TreePath is used extensively by JTree and related classes. For example, JTree represents the selection as an array of TreePaths. When used with JTree, the elements of the path are the objects returned from the TreeModel. When JTree is paired with DefaultTreeModel, the elements of the path are TreeNodes. The following example illustrates extracting the user object from the selection of a JTree:

DefaultMutableTreeNode root = ...;
   DefaultTreeModel model = new DefaultTreeModel(root);
   JTree tree = new JTree(model);
   ...
   TreePath selectedPath = tree.getSelectionPath();
   DefaultMutableTreeNode selectedNode =
       ((DefaultMutableTreeNode)selectedPath.getLastPathComponent()).
       getUserObject();

Subclasses typically need override only


 getLastPathComponent

, and getParentPath. As JTree internally creates TreePaths at various points, it's generally not useful to subclass TreePath and use with JTree.

While TreePath is serializable, a NotSerializableException is thrown if any elements of the path are not serializable.

For further information and examples of using tree paths, see How to Use Trees in The Java Tutorial.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans™ has been added to the java.beans package. Please see XMLEncoder.

See Also:: Serialized Form

Constructor Summary

Constructors
Modifier	Constructor	Description
`protected`	`TreePath()`	Creates an empty `TreePath`.
	`TreePath(Object lastPathComponent)`	Creates a `TreePath` containing a single element.
	`TreePath(Object[] path)`	Creates a `TreePath` from an array.
`protected`	`TreePath(Object[] path, int length)`	Creates a `TreePath` from an array.
`protected`	`TreePath(TreePath parent, Object lastPathComponent)`	Creates a `TreePath` with the specified parent and element.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`equals(Object o)`	Compares this `TreePath` to the specified object.
`Object`	`getLastPathComponent()`	Returns the last element of this path.
`TreePath`	`getParentPath()`	Returns the `TreePath` of the parent.
`Object[]`	`getPath()`	Returns an ordered array of the elements of this `TreePath`.
`Object`	`getPathComponent(int index)`	Returns the path element at the specified index.
`int`	`getPathCount()`	Returns the number of elements in the path.
`int`	`hashCode()`	Returns the hash code of this `TreePath`.
`boolean`	`isDescendant(TreePath aTreePath)`	Returns true if `aTreePath` is a descendant of this `TreePath`.
`TreePath`	`pathByAddingChild(Object child)`	Returns a new path containing all the elements of this path plus `child`.
`String`	`toString()`	Returns a string that displays and identifies this object's properties.

Methods declared in class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

TreePath

@ConstructorProperties("path")
public TreePath(Object[] path)

Creates a TreePath from an array. The array uniquely identifies the path to a node.

Parameters:: path - an array of objects representing the path to a node
Throws:: IllegalArgumentException - if path is null, empty, or contains a null value

TreePath

public TreePath(Object lastPathComponent)

Creates a TreePath containing a single element. This is used to construct a TreePath identifying the root.

Parameters:: lastPathComponent - the root
Throws:: IllegalArgumentException - if lastPathComponent is null
See Also:: TreePath(Object[])

TreePath

protected TreePath(TreePath parent,
                   Object lastPathComponent)

Creates a TreePath with the specified parent and element.

Parameters:: parent - the path to the parent, or null to indicate the root; lastPathComponent - the last path element
Throws:: IllegalArgumentException - if lastPathComponent is null

TreePath

protected TreePath(Object[] path,
                   int length)

Creates a TreePath from an array. The returned TreePath represents the elements of the array from 0 to length - 1.

This constructor is used internally, and generally not useful outside of subclasses.

Parameters:: path - the array to create the TreePath from; length - identifies the number of elements in path to create the TreePath from
Throws:: NullPointerException - if path is null; ArrayIndexOutOfBoundsException - if length - 1 is outside the range of the array; IllegalArgumentException - if any of the elements from 0 to length - 1 are null

TreePath

protected TreePath()

Creates an empty TreePath. This is provided for subclasses that represent paths in a different manner. Subclasses that use this constructor must override getLastPathComponent, and getParentPath.

Method Detail

getPath

public Object[] getPath()

Returns an ordered array of the elements of this TreePath. The first element is the root.

Returns:: an array of the elements in this TreePath

getLastPathComponent

public Object getLastPathComponent()

Returns the last element of this path.

Returns:: the last element in the path

getPathCount

public int getPathCount()

Returns the number of elements in the path.

Returns:: the number of elements in the path

getPathComponent

public Object getPathComponent(int index)

Returns the path element at the specified index.

Parameters:: index - the index of the element requested
Returns:: the element at the specified index
Throws:: IllegalArgumentException - if the index is outside the range of this path

equals

public boolean equals(Object o)

Compares this TreePath to the specified object. This returns true if o is a TreePath with the exact same elements (as determined by using equals on each element of the path).

Overrides:: equals in class Object
Parameters:: o - the object to compare
Returns:: true if this object is the same as the obj argument; false otherwise.
See Also:: Object.hashCode(), HashMap

hashCode

public int hashCode()

Returns the hash code of this TreePath. The hash code of a TreePath is the hash code of the last element in the path.

Overrides:: hashCode in class Object
Returns:: the hashCode for the object
See Also:: Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

isDescendant

public boolean isDescendant(TreePath aTreePath)

Returns true if aTreePath is a descendant of this TreePath. A TreePath P1 is a descendant of a TreePath P2 if P1 contains all of the elements that make up P2's path. For example, if this object has the path [a, b], and aTreePath has the path [a, b, c], then aTreePath is a descendant of this object. However, if aTreePath has the path [a], then it is not a descendant of this object. By this definition a TreePath is always considered a descendant of itself. That is, aTreePath.isDescendant(aTreePath) returns true.

Parameters:: aTreePath - the TreePath to check
Returns:: true if aTreePath is a descendant of this path

pathByAddingChild

public TreePath pathByAddingChild(Object child)

Returns a new path containing all the elements of this path plus child. child is the last element of the newly created TreePath.

Parameters:: child - the path element to add
Returns:: a new path containing all the elements of this path plus child
Throws:: NullPointerException - if child is null

getParentPath

public TreePath getParentPath()

Returns the TreePath of the parent. A return value of null indicates this is the root node.

Returns:: the parent path

toString

public String toString()

Returns a string that displays and identifies this object's properties.

Overrides:: toString in class Object
Returns:: a String representation of this object