TreePath.javaAPI DocJava SE 6 API10563Tue Jun 10 00:27:02 BST 2008javax.swing.tree


public class TreePath extends Object implements Serializable
Represents a path to a node. A TreePath is an array of Objects that are vended from a TreeModel. The elements of the array are ordered such that the root is always the first element (index 0) of the array. TreePath is Serializable, but if any components of the path are not serializable, it will not be written out.

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 JavaBeansTM has been added to the java.beans package. Please see {@link java.beans.XMLEncoder}.

1.31 11/17/05
Scott Violet
Philip Milne

Fields Summary
private TreePath
Path representing the parent, null if lastPathComponent represents the root.
private transient Object
Last path component.
Constructors Summary
public TreePath(Object[] path)
Constructs a path from an array of Objects, uniquely identifying the path from the root of the tree to a specific node, as returned by the tree's data model.

The model is free to return an array of any Objects it needs to represent the path. The DefaultTreeModel returns an array of TreeNode objects. The first TreeNode in the path is the root of the tree, the last TreeNode is the node identified by the path.

path an array of Objects representing the path to a node

        if(path == null || path.length == 0)
            throw new IllegalArgumentException("path in TreePath must be non null and not empty.");
	lastPathComponent = path[path.length - 1];
	if(path.length > 1)
	    parentPath = new TreePath(path, path.length - 1);
public TreePath(Object singlePath)
Constructs a TreePath containing only a single element. This is usually used to construct a TreePath for the the root of the TreeModel.

singlePath an Object representing the path to a node

        if(singlePath == null)
            throw new IllegalArgumentException("path in TreePath must be non null.");
	lastPathComponent = singlePath;
	parentPath = null;
protected TreePath(TreePath parent, Object lastElement)
Constructs a new TreePath, which is the path identified by parent ending in lastElement.

	if(lastElement == null)
            throw new IllegalArgumentException("path in TreePath must be non null.");
	parentPath = parent;
	lastPathComponent = lastElement;
protected TreePath(Object[] path, int length)
Constructs a new TreePath with the identified path components of length length.

	lastPathComponent = path[length - 1];
	if(length > 1)
	    parentPath = new TreePath(path, length - 1);
protected TreePath()
Primarily provided for subclasses that represent paths in a different manner. If a subclass uses this constructor, it should also override the getPath, getPathCount, and getPathComponent methods, and possibly the equals method.

Methods Summary
public booleanequals(java.lang.Object o)
Tests two TreePaths for equality by checking each element of the paths for equality. Two paths are considered equal if they are of the same length, and contain the same elements (.equals).

o the Object to compare

	if(o == this)
	    return true;
        if(o instanceof TreePath) {
            TreePath            oTreePath = (TreePath)o;

	    if(getPathCount() != oTreePath.getPathCount())
		return false;
	    for(TreePath path = this; path != null; path = path.parentPath) {
		if (!(path.lastPathComponent.equals
		      (oTreePath.lastPathComponent))) {
		    return false;
		oTreePath = oTreePath.parentPath;
	    return true;
        return false;
public java.lang.ObjectgetLastPathComponent()
Returns the last component of this path. For a path returned by DefaultTreeModel this will return an instance of TreeNode.

the Object at the end of the path

	return lastPathComponent;
public javax.swing.tree.TreePathgetParentPath()
Returns a path containing all the elements of this object, except the last path component.

	return parentPath;
public java.lang.Object[]getPath()
Returns an ordered array of Objects containing the components of this TreePath. The first element (index 0) is the root.

an array of Objects representing the TreePath

	int            i = getPathCount();
        Object[]       result = new Object[i--];

        for(TreePath path = this; path != null; path = path.parentPath) {
            result[i--] = path.lastPathComponent;
	return result;
public java.lang.ObjectgetPathComponent(int element)
Returns the path component at the specified index.

element an int specifying an element in the path, where 0 is the first element in the path
the Object at that index location
IllegalArgumentException if the index is beyond the length of the path

        int          pathLength = getPathCount();

        if(element < 0 || element >= pathLength)
            throw new IllegalArgumentException("Index " + element + " is out of the specified range");

        TreePath         path = this;

        for(int i = pathLength-1; i != element; i--) {
           path = path.parentPath;
	return path.lastPathComponent;
public intgetPathCount()
Returns the number of elements in the path.

an int giving a count of items the path

        int        result = 0;
        for(TreePath path = this; path != null; path = path.parentPath) {
	return result;
public inthashCode()
Returns the hashCode for the object. The hash code of a TreePath is defined to be the hash code of the last component in the path.

the hashCode for the object

	return lastPathComponent.hashCode();
public booleanisDescendant(javax.swing.tree.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 components 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.

true if aTreePath is a descendant of this path

	if(aTreePath == this)
	    return true;

        if(aTreePath != null) {
            int                 pathLength = getPathCount();
	    int                 oPathLength = aTreePath.getPathCount();

	    if(oPathLength < pathLength)
		// Can't be a descendant, has fewer components in the path.
		return false;
	    while(oPathLength-- > pathLength)
		aTreePath = aTreePath.getParentPath();
	    return equals(aTreePath);
        return false;
public javax.swing.tree.TreePathpathByAddingChild(java.lang.Object child)
Returns a new path containing all the elements of this object plus child. child will be the last element of the newly created TreePath. This will throw a NullPointerException if child is null.

	if(child == null)
	    throw new NullPointerException("Null child not allowed");

	return new TreePath(this, child);
private voidreadObject( s)


        Vector          values = (Vector)s.readObject();
        int             indexCounter = 0;
        int             maxCounter = values.size();

        if(indexCounter < maxCounter && values.elementAt(indexCounter).
           equals("lastPathComponent")) {
            lastPathComponent = values.elementAt(++indexCounter);
public java.lang.StringtoString()
Returns a string that displays and identifies this object's properties.

a String representation of this object

        StringBuffer tempSpot = new StringBuffer("[");

        for(int counter = 0, maxCounter = getPathCount();counter < maxCounter;
	    counter++) {
            if(counter > 0)
                tempSpot.append(", ");
        return tempSpot.toString();
private voidwriteObject( s)


        Vector      values = new Vector();
        boolean     writePath = true;

	if(lastPathComponent != null &&
	   (lastPathComponent instanceof Serializable)) {