| /* |
| * Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package javax.swing.tree; |
| // ISSUE: this class depends on nothing in AWT -- move to java.util? |
| |
| import java.io.*; |
| import java.util.*; |
| |
| |
| /** |
| * A <code>DefaultMutableTreeNode</code> is a general-purpose node in a tree data |
| * structure. |
| * For examples of using default mutable tree nodes, see |
| * <a |
| href="http://java.sun.com/docs/books/tutorial/uiswing/components/tree.html">How to Use Trees</a> |
| * in <em>The Java Tutorial.</em> |
| * |
| * <p> |
| * |
| * A tree node may have at most one parent and 0 or more children. |
| * <code>DefaultMutableTreeNode</code> provides operations for examining and modifying a |
| * node's parent and children and also operations for examining the tree that |
| * the node is a part of. A node's tree is the set of all nodes that can be |
| * reached by starting at the node and following all the possible links to |
| * parents and children. A node with no parent is the root of its tree; a |
| * node with no children is a leaf. A tree may consist of many subtrees, |
| * each node acting as the root for its own subtree. |
| * <p> |
| * This class provides enumerations for efficiently traversing a tree or |
| * subtree in various orders or for following the path between two nodes. |
| * A <code>DefaultMutableTreeNode</code> may also hold a reference to a user object, the |
| * use of which is left to the user. Asking a <code>DefaultMutableTreeNode</code> for its |
| * string representation with <code>toString()</code> returns the string |
| * representation of its user object. |
| * <p> |
| * <b>This is not a thread safe class.</b>If you intend to use |
| * a DefaultMutableTreeNode (or a tree of TreeNodes) in more than one thread, you |
| * need to do your own synchronizing. A good convention to adopt is |
| * synchronizing on the root node of a tree. |
| * <p> |
| * While DefaultMutableTreeNode implements the MutableTreeNode interface and |
| * will allow you to add in any implementation of MutableTreeNode not all |
| * of the methods in DefaultMutableTreeNode will be applicable to all |
| * MutableTreeNodes implementations. Especially with some of the enumerations |
| * that are provided, using some of these methods assumes the |
| * DefaultMutableTreeNode contains only DefaultMutableNode instances. All |
| * of the TreeNode/MutableTreeNode methods will behave as defined no |
| * matter what implementations are added. |
| * |
| * <p> |
| * <strong>Warning:</strong> |
| * 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<sup><font size="-2">TM</font></sup> |
| * has been added to the <code>java.beans</code> package. |
| * Please see {@link java.beans.XMLEncoder}. |
| * |
| * @see MutableTreeNode |
| * |
| * @author Rob Davis |
| */ |
| public class DefaultMutableTreeNode implements Cloneable, |
| MutableTreeNode, Serializable |
| { |
| private static final long serialVersionUID = -4298474751201349152L; |
| |
| /** |
| * An enumeration that is always empty. This is used when an enumeration |
| * of a leaf node's children is requested. |
| */ |
| static public final Enumeration<TreeNode> EMPTY_ENUMERATION |
| = Collections.emptyEnumeration(); |
| |
| /** this node's parent, or null if this node has no parent */ |
| protected MutableTreeNode parent; |
| |
| /** array of children, may be null if this node has no children */ |
| protected Vector children; |
| |
| /** optional user object */ |
| transient protected Object userObject; |
| |
| /** true if the node is able to have children */ |
| protected boolean allowsChildren; |
| |
| |
| /** |
| * Creates a tree node that has no parent and no children, but which |
| * allows children. |
| */ |
| public DefaultMutableTreeNode() { |
| this(null); |
| } |
| |
| /** |
| * Creates a tree node with no parent, no children, but which allows |
| * children, and initializes it with the specified user object. |
| * |
| * @param userObject an Object provided by the user that constitutes |
| * the node's data |
| */ |
| public DefaultMutableTreeNode(Object userObject) { |
| this(userObject, true); |
| } |
| |
| /** |
| * Creates a tree node with no parent, no children, initialized with |
| * the specified user object, and that allows children only if |
| * specified. |
| * |
| * @param userObject an Object provided by the user that constitutes |
| * the node's data |
| * @param allowsChildren if true, the node is allowed to have child |
| * nodes -- otherwise, it is always a leaf node |
| */ |
| public DefaultMutableTreeNode(Object userObject, boolean allowsChildren) { |
| super(); |
| parent = null; |
| this.allowsChildren = allowsChildren; |
| this.userObject = userObject; |
| } |
| |
| |
| // |
| // Primitives |
| // |
| |
| /** |
| * Removes <code>newChild</code> from its present parent (if it has a |
| * parent), sets the child's parent to this node, and then adds the child |
| * to this node's child array at index <code>childIndex</code>. |
| * <code>newChild</code> must not be null and must not be an ancestor of |
| * this node. |
| * |
| * @param newChild the MutableTreeNode to insert under this node |
| * @param childIndex the index in this node's child array |
| * where this node is to be inserted |
| * @exception ArrayIndexOutOfBoundsException if |
| * <code>childIndex</code> is out of bounds |
| * @exception IllegalArgumentException if |
| * <code>newChild</code> is null or is an |
| * ancestor of this node |
| * @exception IllegalStateException if this node does not allow |
| * children |
| * @see #isNodeDescendant |
| */ |
| public void insert(MutableTreeNode newChild, int childIndex) { |
| if (!allowsChildren) { |
| throw new IllegalStateException("node does not allow children"); |
| } else if (newChild == null) { |
| throw new IllegalArgumentException("new child is null"); |
| } else if (isNodeAncestor(newChild)) { |
| throw new IllegalArgumentException("new child is an ancestor"); |
| } |
| |
| MutableTreeNode oldParent = (MutableTreeNode)newChild.getParent(); |
| |
| if (oldParent != null) { |
| oldParent.remove(newChild); |
| } |
| newChild.setParent(this); |
| if (children == null) { |
| children = new Vector(); |
| } |
| children.insertElementAt(newChild, childIndex); |
| } |
| |
| /** |
| * Removes the child at the specified index from this node's children |
| * and sets that node's parent to null. The child node to remove |
| * must be a <code>MutableTreeNode</code>. |
| * |
| * @param childIndex the index in this node's child array |
| * of the child to remove |
| * @exception ArrayIndexOutOfBoundsException if |
| * <code>childIndex</code> is out of bounds |
| */ |
| public void remove(int childIndex) { |
| MutableTreeNode child = (MutableTreeNode)getChildAt(childIndex); |
| children.removeElementAt(childIndex); |
| child.setParent(null); |
| } |
| |
| /** |
| * Sets this node's parent to <code>newParent</code> but does not |
| * change the parent's child array. This method is called from |
| * <code>insert()</code> and <code>remove()</code> to |
| * reassign a child's parent, it should not be messaged from anywhere |
| * else. |
| * |
| * @param newParent this node's new parent |
| */ |
| public void setParent(MutableTreeNode newParent) { |
| parent = newParent; |
| } |
| |
| /** |
| * Returns this node's parent or null if this node has no parent. |
| * |
| * @return this node's parent TreeNode, or null if this node has no parent |
| */ |
| public TreeNode getParent() { |
| return parent; |
| } |
| |
| /** |
| * Returns the child at the specified index in this node's child array. |
| * |
| * @param index an index into this node's child array |
| * @exception ArrayIndexOutOfBoundsException if <code>index</code> |
| * is out of bounds |
| * @return the TreeNode in this node's child array at the specified index |
| */ |
| public TreeNode getChildAt(int index) { |
| if (children == null) { |
| throw new ArrayIndexOutOfBoundsException("node has no children"); |
| } |
| return (TreeNode)children.elementAt(index); |
| } |
| |
| /** |
| * Returns the number of children of this node. |
| * |
| * @return an int giving the number of children of this node |
| */ |
| public int getChildCount() { |
| if (children == null) { |
| return 0; |
| } else { |
| return children.size(); |
| } |
| } |
| |
| /** |
| * Returns the index of the specified child in this node's child array. |
| * If the specified node is not a child of this node, returns |
| * <code>-1</code>. This method performs a linear search and is O(n) |
| * where n is the number of children. |
| * |
| * @param aChild the TreeNode to search for among this node's children |
| * @exception IllegalArgumentException if <code>aChild</code> |
| * is null |
| * @return an int giving the index of the node in this node's child |
| * array, or <code>-1</code> if the specified node is a not |
| * a child of this node |
| */ |
| public int getIndex(TreeNode aChild) { |
| if (aChild == null) { |
| throw new IllegalArgumentException("argument is null"); |
| } |
| |
| if (!isNodeChild(aChild)) { |
| return -1; |
| } |
| return children.indexOf(aChild); // linear search |
| } |
| |
| /** |
| * Creates and returns a forward-order enumeration of this node's |
| * children. Modifying this node's child array invalidates any child |
| * enumerations created before the modification. |
| * |
| * @return an Enumeration of this node's children |
| */ |
| public Enumeration children() { |
| if (children == null) { |
| return EMPTY_ENUMERATION; |
| } else { |
| return children.elements(); |
| } |
| } |
| |
| /** |
| * Determines whether or not this node is allowed to have children. |
| * If <code>allows</code> is false, all of this node's children are |
| * removed. |
| * <p> |
| * Note: By default, a node allows children. |
| * |
| * @param allows true if this node is allowed to have children |
| */ |
| public void setAllowsChildren(boolean allows) { |
| if (allows != allowsChildren) { |
| allowsChildren = allows; |
| if (!allowsChildren) { |
| removeAllChildren(); |
| } |
| } |
| } |
| |
| /** |
| * Returns true if this node is allowed to have children. |
| * |
| * @return true if this node allows children, else false |
| */ |
| public boolean getAllowsChildren() { |
| return allowsChildren; |
| } |
| |
| /** |
| * Sets the user object for this node to <code>userObject</code>. |
| * |
| * @param userObject the Object that constitutes this node's |
| * user-specified data |
| * @see #getUserObject |
| * @see #toString |
| */ |
| public void setUserObject(Object userObject) { |
| this.userObject = userObject; |
| } |
| |
| /** |
| * Returns this node's user object. |
| * |
| * @return the Object stored at this node by the user |
| * @see #setUserObject |
| * @see #toString |
| */ |
| public Object getUserObject() { |
| return userObject; |
| } |
| |
| |
| // |
| // Derived methods |
| // |
| |
| /** |
| * Removes the subtree rooted at this node from the tree, giving this |
| * node a null parent. Does nothing if this node is the root of its |
| * tree. |
| */ |
| public void removeFromParent() { |
| MutableTreeNode parent = (MutableTreeNode)getParent(); |
| if (parent != null) { |
| parent.remove(this); |
| } |
| } |
| |
| /** |
| * Removes <code>aChild</code> from this node's child array, giving it a |
| * null parent. |
| * |
| * @param aChild a child of this node to remove |
| * @exception IllegalArgumentException if <code>aChild</code> |
| * is null or is not a child of this node |
| */ |
| public void remove(MutableTreeNode aChild) { |
| if (aChild == null) { |
| throw new IllegalArgumentException("argument is null"); |
| } |
| |
| if (!isNodeChild(aChild)) { |
| throw new IllegalArgumentException("argument is not a child"); |
| } |
| remove(getIndex(aChild)); // linear search |
| } |
| |
| /** |
| * Removes all of this node's children, setting their parents to null. |
| * If this node has no children, this method does nothing. |
| */ |
| public void removeAllChildren() { |
| for (int i = getChildCount()-1; i >= 0; i--) { |
| remove(i); |
| } |
| } |
| |
| /** |
| * Removes <code>newChild</code> from its parent and makes it a child of |
| * this node by adding it to the end of this node's child array. |
| * |
| * @see #insert |
| * @param newChild node to add as a child of this node |
| * @exception IllegalArgumentException if <code>newChild</code> |
| * is null |
| * @exception IllegalStateException if this node does not allow |
| * children |
| */ |
| public void add(MutableTreeNode newChild) { |
| if(newChild != null && newChild.getParent() == this) |
| insert(newChild, getChildCount() - 1); |
| else |
| insert(newChild, getChildCount()); |
| } |
| |
| |
| |
| // |
| // Tree Queries |
| // |
| |
| /** |
| * Returns true if <code>anotherNode</code> is an ancestor of this node |
| * -- if it is this node, this node's parent, or an ancestor of this |
| * node's parent. (Note that a node is considered an ancestor of itself.) |
| * If <code>anotherNode</code> is null, this method returns false. This |
| * operation is at worst O(h) where h is the distance from the root to |
| * this node. |
| * |
| * @see #isNodeDescendant |
| * @see #getSharedAncestor |
| * @param anotherNode node to test as an ancestor of this node |
| * @return true if this node is a descendant of <code>anotherNode</code> |
| */ |
| public boolean isNodeAncestor(TreeNode anotherNode) { |
| if (anotherNode == null) { |
| return false; |
| } |
| |
| TreeNode ancestor = this; |
| |
| do { |
| if (ancestor == anotherNode) { |
| return true; |
| } |
| } while((ancestor = ancestor.getParent()) != null); |
| |
| return false; |
| } |
| |
| /** |
| * Returns true if <code>anotherNode</code> is a descendant of this node |
| * -- if it is this node, one of this node's children, or a descendant of |
| * one of this node's children. Note that a node is considered a |
| * descendant of itself. If <code>anotherNode</code> is null, returns |
| * false. This operation is at worst O(h) where h is the distance from the |
| * root to <code>anotherNode</code>. |
| * |
| * @see #isNodeAncestor |
| * @see #getSharedAncestor |
| * @param anotherNode node to test as descendant of this node |
| * @return true if this node is an ancestor of <code>anotherNode</code> |
| */ |
| public boolean isNodeDescendant(DefaultMutableTreeNode anotherNode) { |
| if (anotherNode == null) |
| return false; |
| |
| return anotherNode.isNodeAncestor(this); |
| } |
| |
| /** |
| * Returns the nearest common ancestor to this node and <code>aNode</code>. |
| * Returns null, if no such ancestor exists -- if this node and |
| * <code>aNode</code> are in different trees or if <code>aNode</code> is |
| * null. A node is considered an ancestor of itself. |
| * |
| * @see #isNodeAncestor |
| * @see #isNodeDescendant |
| * @param aNode node to find common ancestor with |
| * @return nearest ancestor common to this node and <code>aNode</code>, |
| * or null if none |
| */ |
| public TreeNode getSharedAncestor(DefaultMutableTreeNode aNode) { |
| if (aNode == this) { |
| return this; |
| } else if (aNode == null) { |
| return null; |
| } |
| |
| int level1, level2, diff; |
| TreeNode node1, node2; |
| |
| level1 = getLevel(); |
| level2 = aNode.getLevel(); |
| |
| if (level2 > level1) { |
| diff = level2 - level1; |
| node1 = aNode; |
| node2 = this; |
| } else { |
| diff = level1 - level2; |
| node1 = this; |
| node2 = aNode; |
| } |
| |
| // Go up the tree until the nodes are at the same level |
| while (diff > 0) { |
| node1 = node1.getParent(); |
| diff--; |
| } |
| |
| // Move up the tree until we find a common ancestor. Since we know |
| // that both nodes are at the same level, we won't cross paths |
| // unknowingly (if there is a common ancestor, both nodes hit it in |
| // the same iteration). |
| |
| do { |
| if (node1 == node2) { |
| return node1; |
| } |
| node1 = node1.getParent(); |
| node2 = node2.getParent(); |
| } while (node1 != null);// only need to check one -- they're at the |
| // same level so if one is null, the other is |
| |
| if (node1 != null || node2 != null) { |
| throw new Error ("nodes should be null"); |
| } |
| |
| return null; |
| } |
| |
| |
| /** |
| * Returns true if and only if <code>aNode</code> is in the same tree |
| * as this node. Returns false if <code>aNode</code> is null. |
| * |
| * @see #getSharedAncestor |
| * @see #getRoot |
| * @return true if <code>aNode</code> is in the same tree as this node; |
| * false if <code>aNode</code> is null |
| */ |
| public boolean isNodeRelated(DefaultMutableTreeNode aNode) { |
| return (aNode != null) && (getRoot() == aNode.getRoot()); |
| } |
| |
| |
| /** |
| * Returns the depth of the tree rooted at this node -- the longest |
| * distance from this node to a leaf. If this node has no children, |
| * returns 0. This operation is much more expensive than |
| * <code>getLevel()</code> because it must effectively traverse the entire |
| * tree rooted at this node. |
| * |
| * @see #getLevel |
| * @return the depth of the tree whose root is this node |
| */ |
| public int getDepth() { |
| Object last = null; |
| Enumeration enum_ = breadthFirstEnumeration(); |
| |
| while (enum_.hasMoreElements()) { |
| last = enum_.nextElement(); |
| } |
| |
| if (last == null) { |
| throw new Error ("nodes should be null"); |
| } |
| |
| return ((DefaultMutableTreeNode)last).getLevel() - getLevel(); |
| } |
| |
| |
| |
| /** |
| * Returns the number of levels above this node -- the distance from |
| * the root to this node. If this node is the root, returns 0. |
| * |
| * @see #getDepth |
| * @return the number of levels above this node |
| */ |
| public int getLevel() { |
| TreeNode ancestor; |
| int levels = 0; |
| |
| ancestor = this; |
| while((ancestor = ancestor.getParent()) != null){ |
| levels++; |
| } |
| |
| return levels; |
| } |
| |
| |
| /** |
| * Returns the path from the root, to get to this node. The last |
| * element in the path is this node. |
| * |
| * @return an array of TreeNode objects giving the path, where the |
| * first element in the path is the root and the last |
| * element is this node. |
| */ |
| public TreeNode[] getPath() { |
| return getPathToRoot(this, 0); |
| } |
| |
| /** |
| * Builds the parents of node up to and including the root node, |
| * where the original node is the last element in the returned array. |
| * The length of the returned array gives the node's depth in the |
| * tree. |
| * |
| * @param aNode the TreeNode to get the path for |
| * @param depth an int giving the number of steps already taken towards |
| * the root (on recursive calls), used to size the returned array |
| * @return an array of TreeNodes giving the path from the root to the |
| * specified node |
| */ |
| protected TreeNode[] getPathToRoot(TreeNode aNode, int depth) { |
| TreeNode[] retNodes; |
| |
| /* Check for null, in case someone passed in a null node, or |
| they passed in an element that isn't rooted at root. */ |
| if(aNode == null) { |
| if(depth == 0) |
| return null; |
| else |
| retNodes = new TreeNode[depth]; |
| } |
| else { |
| depth++; |
| retNodes = getPathToRoot(aNode.getParent(), depth); |
| retNodes[retNodes.length - depth] = aNode; |
| } |
| return retNodes; |
| } |
| |
| /** |
| * Returns the user object path, from the root, to get to this node. |
| * If some of the TreeNodes in the path have null user objects, the |
| * returned path will contain nulls. |
| */ |
| public Object[] getUserObjectPath() { |
| TreeNode[] realPath = getPath(); |
| Object[] retPath = new Object[realPath.length]; |
| |
| for(int counter = 0; counter < realPath.length; counter++) |
| retPath[counter] = ((DefaultMutableTreeNode)realPath[counter]) |
| .getUserObject(); |
| return retPath; |
| } |
| |
| /** |
| * Returns the root of the tree that contains this node. The root is |
| * the ancestor with a null parent. |
| * |
| * @see #isNodeAncestor |
| * @return the root of the tree that contains this node |
| */ |
| public TreeNode getRoot() { |
| TreeNode ancestor = this; |
| TreeNode previous; |
| |
| do { |
| previous = ancestor; |
| ancestor = ancestor.getParent(); |
| } while (ancestor != null); |
| |
| return previous; |
| } |
| |
| |
| /** |
| * Returns true if this node is the root of the tree. The root is |
| * the only node in the tree with a null parent; every tree has exactly |
| * one root. |
| * |
| * @return true if this node is the root of its tree |
| */ |
| public boolean isRoot() { |
| return getParent() == null; |
| } |
| |
| |
| /** |
| * Returns the node that follows this node in a preorder traversal of this |
| * node's tree. Returns null if this node is the last node of the |
| * traversal. This is an inefficient way to traverse the entire tree; use |
| * an enumeration, instead. |
| * |
| * @see #preorderEnumeration |
| * @return the node that follows this node in a preorder traversal, or |
| * null if this node is last |
| */ |
| public DefaultMutableTreeNode getNextNode() { |
| if (getChildCount() == 0) { |
| // No children, so look for nextSibling |
| DefaultMutableTreeNode nextSibling = getNextSibling(); |
| |
| if (nextSibling == null) { |
| DefaultMutableTreeNode aNode = (DefaultMutableTreeNode)getParent(); |
| |
| do { |
| if (aNode == null) { |
| return null; |
| } |
| |
| nextSibling = aNode.getNextSibling(); |
| if (nextSibling != null) { |
| return nextSibling; |
| } |
| |
| aNode = (DefaultMutableTreeNode)aNode.getParent(); |
| } while(true); |
| } else { |
| return nextSibling; |
| } |
| } else { |
| return (DefaultMutableTreeNode)getChildAt(0); |
| } |
| } |
| |
| |
| /** |
| * Returns the node that precedes this node in a preorder traversal of |
| * this node's tree. Returns <code>null</code> if this node is the |
| * first node of the traversal -- the root of the tree. |
| * This is an inefficient way to |
| * traverse the entire tree; use an enumeration, instead. |
| * |
| * @see #preorderEnumeration |
| * @return the node that precedes this node in a preorder traversal, or |
| * null if this node is the first |
| */ |
| public DefaultMutableTreeNode getPreviousNode() { |
| DefaultMutableTreeNode previousSibling; |
| DefaultMutableTreeNode myParent = (DefaultMutableTreeNode)getParent(); |
| |
| if (myParent == null) { |
| return null; |
| } |
| |
| previousSibling = getPreviousSibling(); |
| |
| if (previousSibling != null) { |
| if (previousSibling.getChildCount() == 0) |
| return previousSibling; |
| else |
| return previousSibling.getLastLeaf(); |
| } else { |
| return myParent; |
| } |
| } |
| |
| /** |
| * Creates and returns an enumeration that traverses the subtree rooted at |
| * this node in preorder. The first node returned by the enumeration's |
| * <code>nextElement()</code> method is this node.<P> |
| * |
| * Modifying the tree by inserting, removing, or moving a node invalidates |
| * any enumerations created before the modification. |
| * |
| * @see #postorderEnumeration |
| * @return an enumeration for traversing the tree in preorder |
| */ |
| public Enumeration preorderEnumeration() { |
| return new PreorderEnumeration(this); |
| } |
| |
| /** |
| * Creates and returns an enumeration that traverses the subtree rooted at |
| * this node in postorder. The first node returned by the enumeration's |
| * <code>nextElement()</code> method is the leftmost leaf. This is the |
| * same as a depth-first traversal.<P> |
| * |
| * Modifying the tree by inserting, removing, or moving a node invalidates |
| * any enumerations created before the modification. |
| * |
| * @see #depthFirstEnumeration |
| * @see #preorderEnumeration |
| * @return an enumeration for traversing the tree in postorder |
| */ |
| public Enumeration postorderEnumeration() { |
| return new PostorderEnumeration(this); |
| } |
| |
| /** |
| * Creates and returns an enumeration that traverses the subtree rooted at |
| * this node in breadth-first order. The first node returned by the |
| * enumeration's <code>nextElement()</code> method is this node.<P> |
| * |
| * Modifying the tree by inserting, removing, or moving a node invalidates |
| * any enumerations created before the modification. |
| * |
| * @see #depthFirstEnumeration |
| * @return an enumeration for traversing the tree in breadth-first order |
| */ |
| public Enumeration breadthFirstEnumeration() { |
| return new BreadthFirstEnumeration(this); |
| } |
| |
| /** |
| * Creates and returns an enumeration that traverses the subtree rooted at |
| * this node in depth-first order. The first node returned by the |
| * enumeration's <code>nextElement()</code> method is the leftmost leaf. |
| * This is the same as a postorder traversal.<P> |
| * |
| * Modifying the tree by inserting, removing, or moving a node invalidates |
| * any enumerations created before the modification. |
| * |
| * @see #breadthFirstEnumeration |
| * @see #postorderEnumeration |
| * @return an enumeration for traversing the tree in depth-first order |
| */ |
| public Enumeration depthFirstEnumeration() { |
| return postorderEnumeration(); |
| } |
| |
| /** |
| * Creates and returns an enumeration that follows the path from |
| * <code>ancestor</code> to this node. The enumeration's |
| * <code>nextElement()</code> method first returns <code>ancestor</code>, |
| * then the child of <code>ancestor</code> that is an ancestor of this |
| * node, and so on, and finally returns this node. Creation of the |
| * enumeration is O(m) where m is the number of nodes between this node |
| * and <code>ancestor</code>, inclusive. Each <code>nextElement()</code> |
| * message is O(1).<P> |
| * |
| * Modifying the tree by inserting, removing, or moving a node invalidates |
| * any enumerations created before the modification. |
| * |
| * @see #isNodeAncestor |
| * @see #isNodeDescendant |
| * @exception IllegalArgumentException if <code>ancestor</code> is |
| * not an ancestor of this node |
| * @return an enumeration for following the path from an ancestor of |
| * this node to this one |
| */ |
| public Enumeration pathFromAncestorEnumeration(TreeNode ancestor) { |
| return new PathBetweenNodesEnumeration(ancestor, this); |
| } |
| |
| |
| // |
| // Child Queries |
| // |
| |
| /** |
| * Returns true if <code>aNode</code> is a child of this node. If |
| * <code>aNode</code> is null, this method returns false. |
| * |
| * @return true if <code>aNode</code> is a child of this node; false if |
| * <code>aNode</code> is null |
| */ |
| public boolean isNodeChild(TreeNode aNode) { |
| boolean retval; |
| |
| if (aNode == null) { |
| retval = false; |
| } else { |
| if (getChildCount() == 0) { |
| retval = false; |
| } else { |
| retval = (aNode.getParent() == this); |
| } |
| } |
| |
| return retval; |
| } |
| |
| |
| /** |
| * Returns this node's first child. If this node has no children, |
| * throws NoSuchElementException. |
| * |
| * @return the first child of this node |
| * @exception NoSuchElementException if this node has no children |
| */ |
| public TreeNode getFirstChild() { |
| if (getChildCount() == 0) { |
| throw new NoSuchElementException("node has no children"); |
| } |
| return getChildAt(0); |
| } |
| |
| |
| /** |
| * Returns this node's last child. If this node has no children, |
| * throws NoSuchElementException. |
| * |
| * @return the last child of this node |
| * @exception NoSuchElementException if this node has no children |
| */ |
| public TreeNode getLastChild() { |
| if (getChildCount() == 0) { |
| throw new NoSuchElementException("node has no children"); |
| } |
| return getChildAt(getChildCount()-1); |
| } |
| |
| |
| /** |
| * Returns the child in this node's child array that immediately |
| * follows <code>aChild</code>, which must be a child of this node. If |
| * <code>aChild</code> is the last child, returns null. This method |
| * performs a linear search of this node's children for |
| * <code>aChild</code> and is O(n) where n is the number of children; to |
| * traverse the entire array of children, use an enumeration instead. |
| * |
| * @see #children |
| * @exception IllegalArgumentException if <code>aChild</code> is |
| * null or is not a child of this node |
| * @return the child of this node that immediately follows |
| * <code>aChild</code> |
| */ |
| public TreeNode getChildAfter(TreeNode aChild) { |
| if (aChild == null) { |
| throw new IllegalArgumentException("argument is null"); |
| } |
| |
| int index = getIndex(aChild); // linear search |
| |
| if (index == -1) { |
| throw new IllegalArgumentException("node is not a child"); |
| } |
| |
| if (index < getChildCount() - 1) { |
| return getChildAt(index + 1); |
| } else { |
| return null; |
| } |
| } |
| |
| |
| /** |
| * Returns the child in this node's child array that immediately |
| * precedes <code>aChild</code>, which must be a child of this node. If |
| * <code>aChild</code> is the first child, returns null. This method |
| * performs a linear search of this node's children for <code>aChild</code> |
| * and is O(n) where n is the number of children. |
| * |
| * @exception IllegalArgumentException if <code>aChild</code> is null |
| * or is not a child of this node |
| * @return the child of this node that immediately precedes |
| * <code>aChild</code> |
| */ |
| public TreeNode getChildBefore(TreeNode aChild) { |
| if (aChild == null) { |
| throw new IllegalArgumentException("argument is null"); |
| } |
| |
| int index = getIndex(aChild); // linear search |
| |
| if (index == -1) { |
| throw new IllegalArgumentException("argument is not a child"); |
| } |
| |
| if (index > 0) { |
| return getChildAt(index - 1); |
| } else { |
| return null; |
| } |
| } |
| |
| |
| // |
| // Sibling Queries |
| // |
| |
| |
| /** |
| * Returns true if <code>anotherNode</code> is a sibling of (has the |
| * same parent as) this node. A node is its own sibling. If |
| * <code>anotherNode</code> is null, returns false. |
| * |
| * @param anotherNode node to test as sibling of this node |
| * @return true if <code>anotherNode</code> is a sibling of this node |
| */ |
| public boolean isNodeSibling(TreeNode anotherNode) { |
| boolean retval; |
| |
| if (anotherNode == null) { |
| retval = false; |
| } else if (anotherNode == this) { |
| retval = true; |
| } else { |
| TreeNode myParent = getParent(); |
| retval = (myParent != null && myParent == anotherNode.getParent()); |
| |
| if (retval && !((DefaultMutableTreeNode)getParent()) |
| .isNodeChild(anotherNode)) { |
| throw new Error("sibling has different parent"); |
| } |
| } |
| |
| return retval; |
| } |
| |
| |
| /** |
| * Returns the number of siblings of this node. A node is its own sibling |
| * (if it has no parent or no siblings, this method returns |
| * <code>1</code>). |
| * |
| * @return the number of siblings of this node |
| */ |
| public int getSiblingCount() { |
| TreeNode myParent = getParent(); |
| |
| if (myParent == null) { |
| return 1; |
| } else { |
| return myParent.getChildCount(); |
| } |
| } |
| |
| |
| /** |
| * Returns the next sibling of this node in the parent's children array. |
| * Returns null if this node has no parent or is the parent's last child. |
| * This method performs a linear search that is O(n) where n is the number |
| * of children; to traverse the entire array, use the parent's child |
| * enumeration instead. |
| * |
| * @see #children |
| * @return the sibling of this node that immediately follows this node |
| */ |
| public DefaultMutableTreeNode getNextSibling() { |
| DefaultMutableTreeNode retval; |
| |
| DefaultMutableTreeNode myParent = (DefaultMutableTreeNode)getParent(); |
| |
| if (myParent == null) { |
| retval = null; |
| } else { |
| retval = (DefaultMutableTreeNode)myParent.getChildAfter(this); // linear search |
| } |
| |
| if (retval != null && !isNodeSibling(retval)) { |
| throw new Error("child of parent is not a sibling"); |
| } |
| |
| return retval; |
| } |
| |
| |
| /** |
| * Returns the previous sibling of this node in the parent's children |
| * array. Returns null if this node has no parent or is the parent's |
| * first child. This method performs a linear search that is O(n) where n |
| * is the number of children. |
| * |
| * @return the sibling of this node that immediately precedes this node |
| */ |
| public DefaultMutableTreeNode getPreviousSibling() { |
| DefaultMutableTreeNode retval; |
| |
| DefaultMutableTreeNode myParent = (DefaultMutableTreeNode)getParent(); |
| |
| if (myParent == null) { |
| retval = null; |
| } else { |
| retval = (DefaultMutableTreeNode)myParent.getChildBefore(this); // linear search |
| } |
| |
| if (retval != null && !isNodeSibling(retval)) { |
| throw new Error("child of parent is not a sibling"); |
| } |
| |
| return retval; |
| } |
| |
| |
| |
| // |
| // Leaf Queries |
| // |
| |
| /** |
| * Returns true if this node has no children. To distinguish between |
| * nodes that have no children and nodes that <i>cannot</i> have |
| * children (e.g. to distinguish files from empty directories), use this |
| * method in conjunction with <code>getAllowsChildren</code> |
| * |
| * @see #getAllowsChildren |
| * @return true if this node has no children |
| */ |
| public boolean isLeaf() { |
| return (getChildCount() == 0); |
| } |
| |
| |
| /** |
| * Finds and returns the first leaf that is a descendant of this node -- |
| * either this node or its first child's first leaf. |
| * Returns this node if it is a leaf. |
| * |
| * @see #isLeaf |
| * @see #isNodeDescendant |
| * @return the first leaf in the subtree rooted at this node |
| */ |
| public DefaultMutableTreeNode getFirstLeaf() { |
| DefaultMutableTreeNode node = this; |
| |
| while (!node.isLeaf()) { |
| node = (DefaultMutableTreeNode)node.getFirstChild(); |
| } |
| |
| return node; |
| } |
| |
| |
| /** |
| * Finds and returns the last leaf that is a descendant of this node -- |
| * either this node or its last child's last leaf. |
| * Returns this node if it is a leaf. |
| * |
| * @see #isLeaf |
| * @see #isNodeDescendant |
| * @return the last leaf in the subtree rooted at this node |
| */ |
| public DefaultMutableTreeNode getLastLeaf() { |
| DefaultMutableTreeNode node = this; |
| |
| while (!node.isLeaf()) { |
| node = (DefaultMutableTreeNode)node.getLastChild(); |
| } |
| |
| return node; |
| } |
| |
| |
| /** |
| * Returns the leaf after this node or null if this node is the |
| * last leaf in the tree. |
| * <p> |
| * In this implementation of the <code>MutableNode</code> interface, |
| * this operation is very inefficient. In order to determine the |
| * next node, this method first performs a linear search in the |
| * parent's child-list in order to find the current node. |
| * <p> |
| * That implementation makes the operation suitable for short |
| * traversals from a known position. But to traverse all of the |
| * leaves in the tree, you should use <code>depthFirstEnumeration</code> |
| * to enumerate the nodes in the tree and use <code>isLeaf</code> |
| * on each node to determine which are leaves. |
| * |
| * @see #depthFirstEnumeration |
| * @see #isLeaf |
| * @return returns the next leaf past this node |
| */ |
| public DefaultMutableTreeNode getNextLeaf() { |
| DefaultMutableTreeNode nextSibling; |
| DefaultMutableTreeNode myParent = (DefaultMutableTreeNode)getParent(); |
| |
| if (myParent == null) |
| return null; |
| |
| nextSibling = getNextSibling(); // linear search |
| |
| if (nextSibling != null) |
| return nextSibling.getFirstLeaf(); |
| |
| return myParent.getNextLeaf(); // tail recursion |
| } |
| |
| |
| /** |
| * Returns the leaf before this node or null if this node is the |
| * first leaf in the tree. |
| * <p> |
| * In this implementation of the <code>MutableNode</code> interface, |
| * this operation is very inefficient. In order to determine the |
| * previous node, this method first performs a linear search in the |
| * parent's child-list in order to find the current node. |
| * <p> |
| * That implementation makes the operation suitable for short |
| * traversals from a known position. But to traverse all of the |
| * leaves in the tree, you should use <code>depthFirstEnumeration</code> |
| * to enumerate the nodes in the tree and use <code>isLeaf</code> |
| * on each node to determine which are leaves. |
| * |
| * @see #depthFirstEnumeration |
| * @see #isLeaf |
| * @return returns the leaf before this node |
| */ |
| public DefaultMutableTreeNode getPreviousLeaf() { |
| DefaultMutableTreeNode previousSibling; |
| DefaultMutableTreeNode myParent = (DefaultMutableTreeNode)getParent(); |
| |
| if (myParent == null) |
| return null; |
| |
| previousSibling = getPreviousSibling(); // linear search |
| |
| if (previousSibling != null) |
| return previousSibling.getLastLeaf(); |
| |
| return myParent.getPreviousLeaf(); // tail recursion |
| } |
| |
| |
| /** |
| * Returns the total number of leaves that are descendants of this node. |
| * If this node is a leaf, returns <code>1</code>. This method is O(n) |
| * where n is the number of descendants of this node. |
| * |
| * @see #isNodeAncestor |
| * @return the number of leaves beneath this node |
| */ |
| public int getLeafCount() { |
| int count = 0; |
| |
| TreeNode node; |
| Enumeration enum_ = breadthFirstEnumeration(); // order matters not |
| |
| while (enum_.hasMoreElements()) { |
| node = (TreeNode)enum_.nextElement(); |
| if (node.isLeaf()) { |
| count++; |
| } |
| } |
| |
| if (count < 1) { |
| throw new Error("tree has zero leaves"); |
| } |
| |
| return count; |
| } |
| |
| |
| // |
| // Overrides |
| // |
| |
| /** |
| * Returns the result of sending <code>toString()</code> to this node's |
| * user object, or the empty string if the node has no user object. |
| * |
| * @see #getUserObject |
| */ |
| public String toString() { |
| if (userObject == null) { |
| return ""; |
| } else { |
| return userObject.toString(); |
| } |
| } |
| |
| /** |
| * Overridden to make clone public. Returns a shallow copy of this node; |
| * the new node has no parent or children and has a reference to the same |
| * user object, if any. |
| * |
| * @return a copy of this node |
| */ |
| public Object clone() { |
| DefaultMutableTreeNode newNode; |
| |
| try { |
| newNode = (DefaultMutableTreeNode)super.clone(); |
| |
| // shallow copy -- the new node has no parent or children |
| newNode.children = null; |
| newNode.parent = null; |
| |
| } catch (CloneNotSupportedException e) { |
| // Won't happen because we implement Cloneable |
| throw new Error(e.toString()); |
| } |
| |
| return newNode; |
| } |
| |
| |
| // Serialization support. |
| private void writeObject(ObjectOutputStream s) throws IOException { |
| Object[] tValues; |
| |
| s.defaultWriteObject(); |
| // Save the userObject, if its Serializable. |
| if(userObject != null && userObject instanceof Serializable) { |
| tValues = new Object[2]; |
| tValues[0] = "userObject"; |
| tValues[1] = userObject; |
| } |
| else |
| tValues = new Object[0]; |
| s.writeObject(tValues); |
| } |
| |
| private void readObject(ObjectInputStream s) |
| throws IOException, ClassNotFoundException { |
| Object[] tValues; |
| |
| s.defaultReadObject(); |
| |
| tValues = (Object[])s.readObject(); |
| |
| if(tValues.length > 0 && tValues[0].equals("userObject")) |
| userObject = tValues[1]; |
| } |
| |
| private final class PreorderEnumeration implements Enumeration<TreeNode> { |
| private final Stack<Enumeration> stack = new Stack<Enumeration>(); |
| |
| public PreorderEnumeration(TreeNode rootNode) { |
| super(); |
| Vector<TreeNode> v = new Vector<TreeNode>(1); |
| v.addElement(rootNode); // PENDING: don't really need a vector |
| stack.push(v.elements()); |
| } |
| |
| public boolean hasMoreElements() { |
| return (!stack.empty() && stack.peek().hasMoreElements()); |
| } |
| |
| public TreeNode nextElement() { |
| Enumeration enumer = stack.peek(); |
| TreeNode node = (TreeNode)enumer.nextElement(); |
| Enumeration children = node.children(); |
| |
| if (!enumer.hasMoreElements()) { |
| stack.pop(); |
| } |
| if (children.hasMoreElements()) { |
| stack.push(children); |
| } |
| return node; |
| } |
| |
| } // End of class PreorderEnumeration |
| |
| |
| |
| final class PostorderEnumeration implements Enumeration<TreeNode> { |
| protected TreeNode root; |
| protected Enumeration<TreeNode> children; |
| protected Enumeration<TreeNode> subtree; |
| |
| public PostorderEnumeration(TreeNode rootNode) { |
| super(); |
| root = rootNode; |
| children = root.children(); |
| subtree = EMPTY_ENUMERATION; |
| } |
| |
| public boolean hasMoreElements() { |
| return root != null; |
| } |
| |
| public TreeNode nextElement() { |
| TreeNode retval; |
| |
| if (subtree.hasMoreElements()) { |
| retval = subtree.nextElement(); |
| } else if (children.hasMoreElements()) { |
| subtree = new PostorderEnumeration(children.nextElement()); |
| retval = subtree.nextElement(); |
| } else { |
| retval = root; |
| root = null; |
| } |
| |
| return retval; |
| } |
| |
| } // End of class PostorderEnumeration |
| |
| |
| |
| final class BreadthFirstEnumeration implements Enumeration<TreeNode> { |
| protected Queue queue; |
| |
| public BreadthFirstEnumeration(TreeNode rootNode) { |
| super(); |
| Vector<TreeNode> v = new Vector<TreeNode>(1); |
| v.addElement(rootNode); // PENDING: don't really need a vector |
| queue = new Queue(); |
| queue.enqueue(v.elements()); |
| } |
| |
| public boolean hasMoreElements() { |
| return (!queue.isEmpty() && |
| ((Enumeration)queue.firstObject()).hasMoreElements()); |
| } |
| |
| public TreeNode nextElement() { |
| Enumeration enumer = (Enumeration)queue.firstObject(); |
| TreeNode node = (TreeNode)enumer.nextElement(); |
| Enumeration children = node.children(); |
| |
| if (!enumer.hasMoreElements()) { |
| queue.dequeue(); |
| } |
| if (children.hasMoreElements()) { |
| queue.enqueue(children); |
| } |
| return node; |
| } |
| |
| |
| // A simple queue with a linked list data structure. |
| final class Queue { |
| QNode head; // null if empty |
| QNode tail; |
| |
| final class QNode { |
| public Object object; |
| public QNode next; // null if end |
| public QNode(Object object, QNode next) { |
| this.object = object; |
| this.next = next; |
| } |
| } |
| |
| public void enqueue(Object anObject) { |
| if (head == null) { |
| head = tail = new QNode(anObject, null); |
| } else { |
| tail.next = new QNode(anObject, null); |
| tail = tail.next; |
| } |
| } |
| |
| public Object dequeue() { |
| if (head == null) { |
| throw new NoSuchElementException("No more elements"); |
| } |
| |
| Object retval = head.object; |
| QNode oldHead = head; |
| head = head.next; |
| if (head == null) { |
| tail = null; |
| } else { |
| oldHead.next = null; |
| } |
| return retval; |
| } |
| |
| public Object firstObject() { |
| if (head == null) { |
| throw new NoSuchElementException("No more elements"); |
| } |
| |
| return head.object; |
| } |
| |
| public boolean isEmpty() { |
| return head == null; |
| } |
| |
| } // End of class Queue |
| |
| } // End of class BreadthFirstEnumeration |
| |
| |
| |
| final class PathBetweenNodesEnumeration implements Enumeration<TreeNode> { |
| protected Stack<TreeNode> stack; |
| |
| public PathBetweenNodesEnumeration(TreeNode ancestor, |
| TreeNode descendant) |
| { |
| super(); |
| |
| if (ancestor == null || descendant == null) { |
| throw new IllegalArgumentException("argument is null"); |
| } |
| |
| TreeNode current; |
| |
| stack = new Stack<TreeNode>(); |
| stack.push(descendant); |
| |
| current = descendant; |
| while (current != ancestor) { |
| current = current.getParent(); |
| if (current == null && descendant != ancestor) { |
| throw new IllegalArgumentException("node " + ancestor + |
| " is not an ancestor of " + descendant); |
| } |
| stack.push(current); |
| } |
| } |
| |
| public boolean hasMoreElements() { |
| return stack.size() > 0; |
| } |
| |
| public TreeNode nextElement() { |
| try { |
| return stack.pop(); |
| } catch (EmptyStackException e) { |
| throw new NoSuchElementException("No more elements"); |
| } |
| } |
| |
| } // End of class PathBetweenNodesEnumeration |
| |
| |
| |
| } // End of class DefaultMutableTreeNode |
