source: src/main/java/weka/gui/HierarchyPropertyParser.java @ 24

/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program 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 for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    HierarchyPropertyParser.java
 *    Copyright (C) 2001 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.gui;

import java.io.Serializable;
import java.util.StringTokenizer;
import java.util.Vector;

/**
 * This class implements a parser to read properties that have
 * a hierarchy(i.e. tree) structure.  Conceptually it's similar to 
 * the XML DOM/SAX parser but of course is much simpler and 
 * uses dot as the seperator of levels instead of back-slash.<br>
 * It provides interfaces to both build a parser tree and traverse
 * the tree. <br>
 * Note that this implementation does not lock the tree when different
 * threads are traversing it simultaneously, i.e. it's NOT synchronized
 * and multi-thread safe.  It is recommended that later implementation
 * extending this class provide a locking scheme and override the 
 * functions with the "synchronized" modifier (most of them are 
 * goToXXX() and information accessing functions).<p>
 *
 * @author Xin Xu (xx5@cs.waikato.ac.nz)
 * @version $Revision: 1.5 $
 */
public class HierarchyPropertyParser
    implements Serializable {

    /** for serialization */
    private static final long serialVersionUID = -4151103338506077544L;

    /** Keep track of the root of the tree */
    private TreeNode m_Root;
    
    /** Keep track of the current node when traversing the tree */
    private TreeNode m_Current;

    /** The level separate in the path */
    private String m_Seperator = ".";
    
    /** The depth of the tree */
    private int m_Depth = 0;
        
    /** 
     * The inner class implementing a single tree node.
     * All fields are made public simply for convenient access,
     * Although a severe violation of OO Design principle.
     */
    private class TreeNode{
        /** The parent of this node */
        public TreeNode parent = null;
        
        /** The value of this node.  Always String  */
        public String value = null;

        /** The children of this node */
        public Vector children = null;  

        /** The level of this node */
        public int level = 0;

        /** The context of this node */
        public String context = null;
    }
    
    /** Default constructor */
    public HierarchyPropertyParser(){
        m_Root = new TreeNode();
        m_Root.parent = null;
        m_Root.children = new Vector();
        goToRoot();
    }
    
    /**
     * Constructor that builds a tree from the given property with
     * the given delimitor
     *
     * @param p the given property string
     * @param delim the given dilimitor
     */
    public HierarchyPropertyParser(String p, String delim) throws Exception {
        this();         
        build(p, delim);
    }
    
    /**
     * Set the seperator between levels.  Default is dot.
     *
     * @param s the seperator symbol
     */
    public void setSeperator(String s){
        m_Seperator = s;
    }

    /**
     * Get the seperator between levels.  Default is dot.
     *
     * @return the seperator symbol
     */
    public String getSeperator(){ return m_Seperator; }
   
    /** 
     * Build a tree from the given property with the given delimitor
     *
     * @param p the given property
     * @param delim the given delimitor
     */
    public void build(String p, String delim) throws Exception {
        StringTokenizer st = new StringTokenizer(p, delim);
        //System.err.println("delim: "+delim);
        while(st.hasMoreTokens()){
            String property = st.nextToken().trim();
            if(!isHierachic(property))
                throw new Exception("The given property is not in"+
                                    "hierachy structure with seperators!");
            add(property);         
        }
        goToRoot();
    }

    /**
     * Add the given item of property to the tree
     *
     * @param property the given item
     */ 
    public synchronized void add(String property){
        String[] values = tokenize(property);
        if(m_Root.value == null)
            m_Root.value = values[0];
        
        buildBranch(m_Root, values, 1);
    }
    
    /** 
     * Private function to build one branch of the tree
     * based on one property 
     * 
     * @param parent the parent of the node to be built
     * @param values the value of one property
     * @param lvl the level of the node to be built in the tree
     */
    private void buildBranch(TreeNode parent, String[] values, int lvl){
        // Precondition: children is not null
        
        if(lvl == values.length){  // Parent is leaf
            parent.children = null;
            return;
        }
        
        if(lvl > (m_Depth-1))
            m_Depth = lvl+1;  // Depth starts from 1
        
        Vector kids = parent.children;
        int index = search(kids, values[lvl]);
        if(index != -1){
            TreeNode newParent = (TreeNode)kids.elementAt(index);
            if(newParent.children == null)
                newParent.children = new Vector();
            buildBranch(newParent, values, lvl+1);
        }
        else{
            TreeNode added = new TreeNode();
            added.parent = parent;
            added.value = values[lvl];
            added.children = new Vector();
            added.level = lvl;
            if(parent != m_Root)
                added.context = parent.context + m_Seperator + parent.value;
            else
                added.context = parent.value;
            
            kids.addElement(added);
            buildBranch(added, values, lvl+1);
        }
    }
    
    /**
     * Tokenize the given string based on the seperator and
     * put the tokens into an array of strings
     *
     * @param rawString the given string
     * @return an array of strings
     */
    public String[] tokenize(String rawString){
        Vector result = new Vector();
        StringTokenizer tk = new StringTokenizer(rawString, m_Seperator);
        while(tk.hasMoreTokens())
            result.addElement(tk.nextToken());
        
        String[] newStrings = new String[result.size()];
        for(int i=0; i < result.size(); i++)
            newStrings[i] = (String)result.elementAt(i);
        
        return newStrings;
    }
    
    /**
     * Whether the HierarchyPropertyParser contains the given
     * string
     *
     * @param string the given string
     * @return whether contains
     */
    public boolean contains(String string){
        String[] item = tokenize(string);
        if(!item[0].equals(m_Root.value))
            return false;
        
        return isContained(m_Root, item, 1);
    }
    
    /** 
     * Private function to decide whether one level of one branch 
     * contains the relevant values
     * 
     * @param parent the parent of the node to be searched
     * @param values the value of one property
     * @param lvl the level of the node in question
     * @return whether this branch contains the corresponding values
     */
    private boolean isContained(TreeNode parent, String[] values, int lvl){
        if(lvl == values.length)  // Parent is leaf
            return true;
        else if(lvl > values.length)
            return false;
        else{
            Vector kids = parent.children;
            int index = search(kids, values[lvl]);
            if(index != -1){
                TreeNode newParent = (TreeNode)kids.elementAt(index);
                return isContained(newParent, values, lvl+1);
            }
            else
                return false;
        }
    }
    
    /** 
     * Whether the given string has a hierachy structure with
     * the seperators
     *
     * @param string the given string
     */
    public boolean isHierachic(String string){
        int index = string.indexOf(m_Seperator); 
        // Seperator not occur or first occurance at the end
        if((index == (string.length()-1)) || (index == -1))
            return false;
        
        return true;
    }

    /**
     * Helper function to search for the given target string in a 
     * given vector in which the elements' value may hopefully is equal
     * to the target.  If such elements are found the first index
     * is returned, otherwise -1
     *
     * @param vct the given vector
     * @param target the given target string
     * @return the index of the found element, -1 if not found
     */
    public int search(Vector vct, String target){
        if(vct == null)
            return -1;
        
        for(int i=0; i < vct.size(); i++)
            if(target.equals(((TreeNode)vct.elementAt(i)).value))
                return i;
        
        return -1;
    }

    /**
     * Go to a certain node of the tree according to the specified path
     * Note that the path must be absolute path from the root.  <br>
     * For relative path, see goDown(String path).
     *
     * @param path the given absolute path
     * @return whether the path exists, if false the current position does
     * not move
     */
    public synchronized boolean goTo(String path){
        if(!isHierachic(path)){
            if(m_Root.value.equals(path)){
                goToRoot();
                return true;
            }
            else
                return false;
        }
        
        TreeNode old = m_Current;
        m_Current = new TreeNode(); 
        goToRoot();
        String[] nodes = tokenize(path);
        if(!m_Current.value.equals(nodes[0]))
            return false;

        for(int i=1; i < nodes.length; i++){
            int pos = search(m_Current.children, nodes[i]);
            if(pos == -1){
                m_Current = old;
                return false;
            }
            m_Current = (TreeNode)m_Current.children.elementAt(pos);
        }
        
        return true;
    }

    /**
     * Go to a certain node of the tree down from the current node 
     * according to the specified relative path.  The path does not
     * contain the value of current node
     * 
     * @param path the given relative path
     * @return whether the path exists, if false the current position does
     * not move
     */
    public synchronized boolean goDown(String path){
        if(!isHierachic(path))
            return goToChild(path);

        TreeNode old = m_Current;
        m_Current = new TreeNode(); 
        String[] nodes = tokenize(path);
        int pos = search(old.children, nodes[0]);
        if(pos == -1){
            m_Current = old;
            return false;
        }
      
        m_Current = (TreeNode)old.children.elementAt(pos);
        for(int i=1; i < nodes.length; i++){
            pos = search(m_Current.children, nodes[i]);
            if(pos == -1){
                m_Current = old;
                return false;
            }
            
            m_Current = (TreeNode)m_Current.children.elementAt(pos);
        }
        
        return true;
    }

    /**
     * Go to the root of the tree
     */    
    public synchronized void goToRoot(){
        m_Current=m_Root;
    }

    /**
     * Go to the parent from the current position in the tree
     * If the current position is the root, it stays there and does 
     * not move
     */
    public synchronized void goToParent(){
        if(m_Current.parent != null)  // Not root
            m_Current = m_Current.parent;
    }
    
    /**
     * Go to one child node from the current position in the tree
     * according to the given value <br>
     * If the child node with the given value cannot be found it
     * returns false, true otherwise.  If false, the current position
     * does not change
     * 
     * @param value the value of the given child
     * @return whether the child can be found
     */
    public synchronized boolean goToChild(String value){
        if(m_Current.children == null) // Leaf
            return false;
        
        int pos = search(m_Current.children, value);
        if(pos == -1)
            return false;
        
        m_Current = (TreeNode)m_Current.children.elementAt(pos);        
        return true;
    }
    
    /**
     * Go to one child node from the current position in the tree
     * according to the given position <br>
     *
     * @param pos the position of the given child
     * @exception Exception if the position is out of range or leaf is reached
     */
    public synchronized void goToChild(int pos) throws Exception {
        if((m_Current.children == null) || 
           (pos < 0) || (pos >= m_Current.children.size()))
            throw new Exception("Position out of range or leaf reached");
        
        m_Current = (TreeNode)m_Current.children.elementAt(pos);
    }

    /**
     * The number of the children nodes. If current node is leaf, it
     * returns 0.
     * 
     * @return the number of the children nodes of the current position
     */    
    public synchronized int numChildren(){
        if(m_Current.children == null) // Leaf
            return 0;
        
        return m_Current.children.size(); 
    }
    
    /**
     * The value in the children nodes. If current node is leaf, it
     * returns null.
     * 
     * @return the value in the children nodes
     */    
    public synchronized String[] childrenValues(){
        if(m_Current.children == null) // Leaf
            return null;
        else{
            Vector kids = m_Current.children;
            String[] values = new String[kids.size()];
            for(int i=0; i < kids.size(); i++)
                values[i] = ((TreeNode)kids.elementAt(i)).value;
            return values;
        }
    }

    /**
     * The value in the parent node. If current node is root, it
     * returns null.
     * 
     * @return the value in the parent node
     */    
    public synchronized String parentValue(){
        if(m_Current.parent != null)  // Not root
            return m_Current.parent.value;
        else return null;
    }

    /**
     * Whether the current position is a leaf
     *
     * @return whether the current position is a leaf
     */
    public synchronized boolean isLeafReached(){
        return (m_Current.children == null);
    }
    
    /**
     * Whether the current position is the root
     *
     * @return whether the current position is the root
     */
    public synchronized boolean isRootReached(){
        return (m_Current.parent == null);
    }
    
    /** 
     * Get the value of current node
     *
     * @return value level
     */ 
    public synchronized String getValue(){ return m_Current.value; }
    
    /** 
     * Get the level of current node.  Note the level starts from 0
     *
     * @return the level
     */ 
    public synchronized int getLevel(){ return m_Current.level; }

    /** 
     * Get the depth of the tree, i.e. (the largest level)+1
     *
     * @return the depth of the tree
     */
    public int depth(){ return m_Depth; }
    
    /**
     * The context of the current node, i.e. the path from the
     * root to the parent node of the current node, seperated by
     * the seperator.  If root, it returns null
     *
     * @return the context path
     */
    public synchronized String context(){
        return m_Current.context;
    }
    
    /**
     * The full value of the current node, i.e. its context + seperator
     * + its value.  For root, only its value.
     *
     * @return the context path
     */
    public synchronized String fullValue(){
        if(m_Current == m_Root)
            return m_Root.value;
        else    
            return (m_Current.context + m_Seperator + m_Current.value);
    }


    /**
     * Show the whole tree in text format
     *
     * @return the whole tree in text format
     */
    public String showTree(){
        return showNode(m_Root, null);
    }
    
    /**
     * Show one node of the tree in text format
     *
     * @param node the node in question
     * @return the node in text format
     */
    private String showNode(TreeNode node, boolean[] hasBar){
        StringBuffer text =  new StringBuffer();        

        for(int i=0; i < (node.level - 1); i++)
            if(hasBar[i])
                text.append("  |       ");
            else
                text.append("          ");

        if(node.level != 0)
            text.append("  |------ ");
        text.append(node.value+"("+node.level+")"+"["+node.context+"]\n");

        if(node.children != null)
            for(int i=0; i < node.children.size(); i++){
                boolean[] newBar = new boolean[node.level+1];
                int lvl = node.level;

                if(hasBar != null)
                    for(int j=0; j < lvl; j++)
                        newBar[j] = hasBar[j];
                
                if((i == (node.children.size()-1)))
                    newBar[lvl] = false;
                else
                    newBar[lvl] = true;

                text.append(showNode((TreeNode)node.children.elementAt(i), newBar));            
            }
        
        return text.toString();
    }
    
    /**
     * Tests out the parser.
     *
     * @param args should contain nothing
     */
    public static void main(String args[]){
        StringBuffer sb = new StringBuffer();
        sb.append("node1.node1_1.node1_1_1.node1_1_1_1, ");
        sb.append("node1.node1_1.node1_1_1.node1_1_1_2, ");
        sb.append("node1.node1_1.node1_1_1.node1_1_1_3, ");
        sb.append("node1.node1_1.node1_1_2.node1_1_2_1, ");
        sb.append("node1.node1_1.node1_1_3.node1_1_3_1, ");
        sb.append("node1.node1_2.node1_2_1.node1_2_1_1, ");
        sb.append("node1.node1_2.node1_2_3.node1_2_3_1, ");
        sb.append("node1.node1_3.node1_3_3.node1_3_3_1, ");
        sb.append("node1.node1_3.node1_3_3.node1_3_3_2, ");

        String p = sb.toString();
        try{
            HierarchyPropertyParser hpp = new HierarchyPropertyParser(p, ", ");
            System.out.println("seperator: "+hpp.getSeperator());
            System.out.println("depth: "+hpp.depth());
            System.out.println("The tree:\n\n"+hpp.showTree());
            hpp.goToRoot();
            System.out.println("goto: "+hpp.goTo("node1.node1_2.node1_2_1")
                               +": "+hpp.getValue()+" | "+hpp.fullValue()+
                               " leaf? "+ hpp.isLeafReached());
            System.out.println("go down(wrong): "+hpp.goDown("node1"));
            System.out.println("Stay still? "+hpp.getValue());
            System.out.println("go to child: "+hpp.goToChild("node1_2_1_1")
                               +": "+hpp.getValue()+" | "+hpp.fullValue()+
                               " leaf? "+ hpp.isLeafReached()
                               +" root? "+ hpp.isRootReached());
            System.out.println("parent: "+hpp.parentValue());
            System.out.println("level: "+hpp.getLevel());
            System.out.println("context: "+hpp.context());
            hpp.goToRoot();
            System.out.println("After gotoRoot. leaf? "+ hpp.isLeafReached()
                               +" root? "+ hpp.isRootReached());
            System.out.println("Go down(correct): "+
                               hpp.goDown("node1_1.node1_1_1")+
                               " value: "+hpp.getValue()+" | "+hpp.fullValue()
                               +" level: "+hpp.getLevel()
                               +" leaf? "+ hpp.isLeafReached()
                               +" root? "+ hpp.isRootReached());
            hpp.goToParent();
            System.out.println("value: "+hpp.getValue()+" | "+hpp.fullValue());
            System.out.println("level: "+hpp.getLevel());
            
            String[] chd = hpp.childrenValues();
            for(int i=0; i < chd.length; i++){
                System.out.print("children "+i+": "+chd[i]);
                hpp.goDown(chd[i]);
                System.out.println("real value: "+hpp.getValue()+" | "+
                                   hpp.fullValue()+
                                   "(level: "+hpp.getLevel()+")");
                hpp.goToParent();
            }
            
            System.out.println("Another way to go to root:"+hpp.goTo("node1")
                               +": "+hpp.getValue()+" | "+hpp.fullValue()); 
        }catch(Exception e){
            System.out.println(e.getMessage());
            e.printStackTrace();
        }
    }
}