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package org.jdesktop.swingx.tree;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Enumeration;
import java.util.NoSuchElementException;
import java.util.Queue;
import java.util.Vector;
import java.util.logging.Logger;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;
/**
* Contains convenience classes/methods for handling hierarchical Swing structures.
*
* @author Jeanette Winzenburg, Berlin
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public class TreeUtilities {
/**
* An enumeration that is always empty.
*/
public static final Enumeration EMPTY_ENUMERATION
= new Enumeration() {
@Override
public boolean hasMoreElements() { return false; }
@Override
public Object nextElement() {
throw new NoSuchElementException("No more elements");
}
};
/**
* Implementation of a preorder traversal of a TreeModel.
*/
public static class PreorderModelEnumeration implements Enumeration {
protected Deque stack;
protected TreeModel model;
// the last component is the current subtree to travers
private TreePath path;
/**
* Instantiates a preorder traversal starting from the root of the
* TreeModel.
*
* @param model the TreeModel to travers.
*/
public PreorderModelEnumeration(TreeModel model) {
this(model, model.getRoot());
}
/**
* Instantiates a preorder traversal of the TreeModel which
* starts at the given node. It iterates over all nodes of the
* subtree, only.
*
* @param model the TreeModel to travers.
* @param node the node to start
*/
public PreorderModelEnumeration(TreeModel model, Object node) {
this.model = model;
stack = new ArrayDeque();
pushNodeAsEnumeration(node);
}
/**
* Instantiates a preorder traversal of the TreeModel which starts at the
* last path component of the given TreePath. It iterates over all nodes
* of the subtree and all of its siblings, with the same end as a traversal
* starting at the model's roolt would have.
*
* @param model the TreeModel to travers.
* @param path the TreePath to start from
*/
public PreorderModelEnumeration(TreeModel model, TreePath path) {
this(model, path.getLastPathComponent());
this.path = path;
}
@Override
public boolean hasMoreElements() {
return (!stack.isEmpty() && stack.peek().hasMoreElements());
}
@Override
public Object nextElement() {
Enumeration enumer = stack.peek();
Object node = enumer.nextElement();
Enumeration children = children(model, node);
if (!enumer.hasMoreElements()) {
stack.pop();
}
if (children.hasMoreElements()) {
stack.push(children);
}
if (!hasMoreElements()) {
// check if there are more subtrees to travers
// and update internal state accordingly
updateSubtree();
}
return node;
}
/**
*
*/
private void updateSubtree() {
if (path == null) return;
TreePath parentPath = path.getParentPath();
if (parentPath == null) {
// root
path = null;
return;
}
Object parent = parentPath.getLastPathComponent();
Object currentNode = path.getLastPathComponent();
int currentIndex = model.getIndexOfChild(parent, currentNode);
if (currentIndex +1 < model.getChildCount(parent)) {
// use sibling
Object child = model.getChild(parent, currentIndex + 1);
path = parentPath.pathByAddingChild(child);
pushNodeAsEnumeration(child);
} else {
path = parentPath;
// up one level
updateSubtree();
}
}
private void pushNodeAsEnumeration(Object node) {
// single element enum
Vector v = new Vector(1);
v.add(node);
stack.push(v.elements()); //children(model));
}
} // End of class PreorderEnumeration
/**
* Implementation of a breadthFirst traversal of a subtree in a TreeModel.
*/
public static class BreadthFirstModelEnumeration implements Enumeration {
protected Queue queue;
private TreeModel model;
public BreadthFirstModelEnumeration(TreeModel model) {
this(model, model.getRoot());
}
public BreadthFirstModelEnumeration(TreeModel model, Object node) {
this.model = model;
// Vector is just used for getting an Enumeration easily
Vector v = new Vector(1);
v.addElement(node);
queue = new ArrayDeque();
queue.offer(v.elements());
}
@Override
public boolean hasMoreElements() {
return !queue.isEmpty() &&
queue.peek().hasMoreElements();
}
@Override
public Object nextElement() {
// look at head
Enumeration enumer = queue.peek();
Object node = enumer.nextElement();
Enumeration children = children(model, node);
if (!enumer.hasMoreElements()) {
// remove head
queue.poll();
}
if (children.hasMoreElements()) {
// add at tail
queue.offer(children);
}
return node;
}
} // End of class BreadthFirstEnumeration
/**
* Implementation of a postorder traversal of a subtree in a TreeModel.
*/
public static class PostorderModelEnumeration implements Enumeration {
protected TreeModel model;
protected Object root;
protected Enumeration children;
protected Enumeration subtree;
public PostorderModelEnumeration(TreeModel model) {
this(model, model.getRoot());
}
public PostorderModelEnumeration(TreeModel model, Object node) {
this.model = model;
root = node;
children = children(model, root);
subtree = EMPTY_ENUMERATION;
}
@Override
public boolean hasMoreElements() {
return root != null;
}
@Override
public Object nextElement() {
Object retval;
if (subtree.hasMoreElements()) {
retval = subtree.nextElement();
} else if (children.hasMoreElements()) {
subtree = new PostorderModelEnumeration(model,
children.nextElement());
retval = subtree.nextElement();
} else {
retval = root;
root = null;
}
return retval;
}
} // End of class PostorderEnumeration
/**
* Implementation of a preorder traversal of a subtree with nodes of type TreeNode.
*/
public static class PreorderNodeEnumeration implements Enumeration {
protected Deque> stack;
public PreorderNodeEnumeration(M rootNode) {
// Vector is just used for getting an Enumeration easily
Vector v = new Vector(1);
v.addElement(rootNode);
stack = new ArrayDeque>();
stack.push(v.elements());
}
@Override
public boolean hasMoreElements() {
return (!stack.isEmpty() &&
stack.peek().hasMoreElements());
}
@Override
public M nextElement() {
Enumeration enumer = stack.peek();
M node = enumer.nextElement();
Enumeration children = getChildren(node);
if (!enumer.hasMoreElements()) {
stack.pop();
}
if (children.hasMoreElements()) {
stack.push(children);
}
return node;
}
protected Enumeration getChildren(M node) {
Enumeration children = node.children();
return children;
}
} // End of class PreorderEnumeration
/**
* Implementation of a postorder traversal of a subtree with nodes of type TreeNode.
*/
public static class PostorderNodeEnumeration implements Enumeration {
protected M root;
protected Enumeration children;
protected Enumeration subtree;
public PostorderNodeEnumeration(M rootNode) {
super();
root = rootNode;
children = getChildren(rootNode);
subtree = EMPTY_ENUMERATION;
}
@Override
public boolean hasMoreElements() {
return root != null;
}
@Override
public M nextElement() {
M retval;
if (subtree.hasMoreElements()) {
retval = subtree.nextElement();
} else if (children.hasMoreElements()) {
subtree = createSubTree(children.nextElement());
retval = subtree.nextElement();
} else {
retval = root;
root = null;
}
return retval;
}
/**
* Creates and returns a PostorderEnumeration on the given node.
*
* @param node the node to create the PostorderEnumeration for
* @return the PostorderEnumeration on the given node
*/
protected PostorderNodeEnumeration createSubTree(M node) {
return new PostorderNodeEnumeration(node);
}
/**
* Returns an enumeration on the children of the root node.
* @param node
* @return
*/
protected Enumeration getChildren(M node) {
return node.children();
}
} // End of class PostorderEnumeration
/**
* Implementation of a breadthFirst traversal of a subtree with nodes of type TreeNode.
*/
public static class BreadthFirstNodeEnumeration implements Enumeration {
protected Queue> queue;
public BreadthFirstNodeEnumeration(M rootNode) {
// Vector is just used for getting an Enumeration easily
Vector v = new Vector(1);
v.addElement(rootNode);
queue = new ArrayDeque>();
queue.offer(v.elements());
}
@Override
public boolean hasMoreElements() {
return !queue.isEmpty() &&
queue.peek().hasMoreElements();
}
@Override
public M nextElement() {
// look at head
Enumeration enumer = queue.peek();
M node = enumer.nextElement();
Enumeration children = getChildren(node);
if (!enumer.hasMoreElements()) {
// remove head
queue.poll();
}
if (children.hasMoreElements()) {
// add at tail
queue.offer(children);
}
return node;
}
protected Enumeration getChildren(M node) {
Enumeration children = node.children();
return children;
}
} // End of class BreadthFirstEnumeration
/**
* Creates and returns an Enumeration across the direct children of the
* rootNode in the given TreeModel.
*
* @param model the TreeModel which contains parent, must not be null
* @return an Enumeration across the direct children of the model's root, the enumeration
* is empty if the root is null or contains no children
*/
public static Enumeration children(TreeModel model) {
return children(model, model.getRoot());
}
/**
* Creates and returns an Enumeration across the direct children of parentNode
* in the given TreeModel.
*
* @param model the TreeModel which contains parent, must not be null
* @param parent the parent of the enumerated children
* @return an Enumeration across the direct children of parent, the enumeration
* is empty if the parent is null or contains no children
*/
public static Enumeration children(final TreeModel model, final Object parent) {
if (parent == null || model.isLeaf(parent)) {
return EMPTY_ENUMERATION;
}
Enumeration e = new Enumeration() {
int currentIndex = 0;
@Override
public boolean hasMoreElements() {
return model.getChildCount(parent) > currentIndex;
}
@Override
public Object nextElement() {
return model.getChild(parent, currentIndex++);
}
};
return e;
}
private TreeUtilities() {}
@SuppressWarnings("unused")
private static final Logger LOG = Logger.getLogger(TreeUtilities.class
.getName());
}