Implementation of LISP trees in Java

I have a problem with implementation of a something similar to a LISP tree in Java. That means that I want to be able to combine different if-else-conditions from a set of variables and operators and run it. For example, if (variable) (operator) (variable) (operator2) (variable) (operator) (variable)
whereby :
variable: means a variable
operator: <, >, =, +, _,
variable: variable
operator2: &&, ||, etc
I don't know how to do in a way that a variable can be picked up from a set, operator can be picked up from a set and operator2 can also be picked up from a set.

Lisp doesn't use trees... it uses lists. In fact, Lisp stands for "List Processing".
Take a look at the java.util.LinkedList class. If you make a LinkedList of Nodes, where each Node contains an Object car and LinkedList cdr, you've got yourself a Lisp list implementation!

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Implementing DOM Interface with existing Java classes

I had planned on using some tree-like Java classes as a Document Object Model, which would give me access to all sorts of XML and DOM tools like parsers and XSLT transformers. Initially, I thought all that would be neccessary is to implement all the DOM Interfaces in org.w3c.dom and then I would have a set of classes that conformed to DOM Level 1. It was my understanding that interfaces such as DOMImplementation and Document would interface with various XML tools, allowing creation of a class that implements Document and then Document would have its various factory methods that know how to create the various DOM nodes such as Element, Attr, Text, NamedNodeMap, NodeList, etc.
The problem I'm seeing now is that the JAXP specification (which is what the latest Xerces and Xalan tools conform to) has something called a DocumentBuilder and DocumentBuilderFactory that appear to be necessary to tell the framework what type of class to instantiate that implements the Document DOM interface. Those appear to have a lot of methods that deal with parsing of XML documents and I didn't really want to write or even subclass any existing Parsers in order to get the functionality of traversing and transforming a set of classes that implement the DOM interface.
Am I missing something here? Is it possible to plug in any (set of classes for) DOMImplementation and get them to work with the various DOM and XML tools out there?
Is there an easier way to allow parts of an application access to internal data structures but have the more generic tools or APIs, such as XSL transformers, access that same set of classes as a DOM with the generic DOM interface methods?
Can someone provide me with some guidance here? I'm in the process of finalizing some design on a system and need to know if this is possible or if I need to alter my design.
Thanks.

If I understand you correctly, I think I am working on a similar issue. I am unhappy with the methods given by the DOM for retrieving data from the XML file and for building a file. Our software has a bunch of code that uses these classes and it is extremely ugly. My solution was to create a facade on top of the DOM model. Essentially I have some simple classes that store all the pertinent info (for me) about the XML structure. Essentially that is the element or attribute name, its values and in the case of the element, it's children. This makes it easier for me to build and retreive the data. What I then built was a loader class and a builder class. The loader takes an XML file and parses it in using the DOM classes and builds a structure using my classes and returns the root element. The builder takes a root element and creates a DOM object out of it. This frees me of having to code around the DOM classes all over the place and makes it simple to upgrade our XML code if the DOM changes or a better DOM is released. I am using factories to facilitate this and allow me to have loaders for specific types of XML documents so that I can have a class for each which further simplifies the XML related tasks of other developers on my team.

Implement a greedy search in java

Implement a greedy serch in java for the map of romania .goal state is bucharest.
1.not to visit the same city twice
2.give the search trees
3.try 3 initial states

No. Do it yourself. This is a help forum, not a "here's my requirements do it for me" forum.

Binary trees in Java

Hi there
Do you have any suggestions about how to implement trees or binary trees in Java?
As far as I know there are already some libraries for that, but I don't know how to use them. Was trying to get some implementation examples but I'm still very confused.
How can I use for example:
removeChild(Tree t)
addChild(Tree t)
isLeaf()
Thanks in advance

Lulu wrote:
Hi there
I have several questions about binary trees
Let's see, I use TreeMap to create them with the following code:
TreeMap treeMap = new TreeMap<Integer, String>();
treeMap.put("first", "Fruit");
treeMap.put("second","Orange");
treeMap.put("third", "Banana");
treeMap.put("fourth", "Apple");You've defined the map to hold integer keys and strings as values, yet you're trying to add string keys and string values to it: that won't work.
If this is a map how do I define if the data should go to the left or to the right of certain node?That is all done for you. In a TreeMap (using the no-args constructor), you can only store objects that are comparable to each other (so, they must implement the Comparable interface!). So the dirty work of deciding if the entry should be stored, or traversed, into the left or right subtree of a node, is all done behind the scenes.
Also note that TreeMap is not backed up by a binary tree, or a binary search tree, but by a red-black tree. A red-black tree is a self balancing binary tree structure.
Should I have dynamical keys so that they increase automatically when adding new data?
According to a webpage I should use Comparator(), is that to find the data in the tree and retrieve the key?
ThanksI am not sure what it is you want. I am under the impression that you have to write a binary tree (or a binary search tree) for a course for school/university. Is that correct? If so, then I don't think you're permitted to use a TreeMap, but you'll have to write your own classes.

Populate Flex Tree from Java Code (Database)

Hi
Can someone please help me? I'm very new to using flex. I'm
basically trying to create a tree that is populated from data in my
database. I am using hibernate to fetch that data.
The plan is to basically create the tree in Java code (since
I don't want any processing done on the client PC) and then pass
this to the flex tree (or an actionscript data structure that is
compatible as the tree datasource)
I am creating the java tree using DocumentImpl. Is this
correct? What class would work?
Element e = null;
Node n = null;
Document xmldoc= new DocumentImpl();
Element root = xmldoc.createElement("USERS");

quote:
Originally posted by:
ntsiii
Stop running and get a map (read the documents)
This is hardly a useful comment and must discourage new users
from asking questions. If you think the documentation relating to
the use of the tree control is straightforward then I beg to
differ.
If you are aware of a clear example of how to use the data
tree with a php backend returning a remote data object please
enlighten me. Meanwhile I continue my search but not within the
livedocs.
One site I have found that may be of use is
http://flexdiary.blogspot.com/2009/01/lazy-loading-tree-example-file-posted.html
Not everyone is an expert.

Creating non binary trees in Java

Hi everybody actually i am used in creating binary trees in java,can u please tell me how do we create non binary -trees in java.

Hi,
Can u let us know the application area for Non binary tree.
S Rudra

Non binary trees in java

Hi guys i am used in creating binary trees ,tell me how do we create non binary trees in java.

public class Node {
private final Object payload;
private final Set<Node> children;
public Node(Object payload) {
this.payload = payload;
children = new HashSet<Node>();
// now add methods to add/remove children, a method to do something with the payload (say,
// a protected method that passes the payload to a method specified by some kind of interface),
// and methods to recurse over children.
}Actually rather than using Object probably should have generic-ized the class, but whatever.

Binary Tree in Java - ******URGENT********

HI,
i want to represent a binary tree in java. is there any way of doing that.
thanx
sraphson

HI,
i want to represent a binary tree in java. is there
e any way of doing that.
thanx
sraphsonFirst, what is a binary tree? Do you know how the binary tree looks like on puesdo code? How about a representation in terms of numbers? What is a tree? What is binary? The reason I ask is, what do you know about programming?
Asking to represent a binary tree in java seems like a question who doesn't know how it looks like in the first please. Believe me, I am one of them. I am not at this level yet. If you are taking a class that is teaching binary trees and you don't know how it looks like, go back to your notes.
Sounds harsh, but it is better to hear it from a person that doesn't know either then a boss that hired you because Computer Science was what you degree said. Yet, you don't know how to program?
Telling you will not help you learn. I can show you tutorials of trees would be start on where to learn.
HOW TO USE TREES (oops this is too simple, but it is a good example)
http://java.sun.com/docs/books/tutorial/uiswing/components/tree.html
CS312 Data Structures and Analysis of Algorithms
(Here is a course about trees. Search and learn)
http://www.calstatela.edu/faculty/jmiller6/cs312-winter2003/index.htm

How to implement a note on a Java AS(i.e.Enterprise portal)

Hello
How to implement a note on a Java AS(i.e.Enterprise portal)
Thx in advance

Hi,
Could you please let us know what kind of note you want to implement on EP ?
Thanks
Sunny

Implementing n-tier Architecture using java

Hi !!
I wish to know how I can proceed to implement n-tier application using java
or how to implement n-tier application with JBuilder.
Thanks!

Easypublic class nTier {
public static void main(String[] args) {
    int n =5;
    for (int i=0; i<n; i++) {
      System.out.println(i + " tier");
}Ted.

Implementing circular-left shift in java

i'm an fresher currently in a project on SHA algorithm
i would like to know how to implement circular left shift in java
whether there is any method in java to implement this ,
if in case what package i have to import.
please reply me,
yours sincerely
hari hara ganesh.d
india

int number= ...;
int shift= ...;
int rotleft= (number<<shift)|(number>>>32-shift);kind regards,
Jos

Implementation of a parse tree in java (HELP!!!)

I want to be able to do this in java, please how can i implement this.
     +
          a *
          b c

It's not entirely clear what you want to do. That expression in infix notation (standard notation) would be "(b a c) + *" which doesn't make any sense. The leaves of the tree should be values, and non-leaf nodes should be operators. You can implement this by using a tree datatype in Java.

Implementation of a parse tree in Java (Urgent)

How best can a parse tree be implemented in java, i have read some online information that suggest use of data structures, but i am still not clear on how to do it.

Well, you need a tree. A logical way to structure a tree is out of "node" objects. A node presumeably will hold some data, and may also have one or more subnodes.
So the root of your effort ought to go into designing the node - data it will hold, and getters and setters, and operations to walk the tree.

Tree traversal Java Program

Hi,
I need the below implementation in JAVA :
Scenario : Need to traverse once through all nodes of a tree
Input :
(i) Starting node of traversal
(ii) List of nodes in the Tree
(iii) Parent of all nodes, say, mapping like (each_node, list_of_its_parent) (OR) (each_node, list_of_its_child)
Eg TREE :
A___________________ F
| | | |
|__B | | |
| C D_____|
| |___
H | |
E G
In the above example
(node, child_list) :--
=============
(A, {B,C,D})
(B, {H})
(C, {E,G})
(F, {D})
In the above tree, if any node is given as the starting node, I need to traverse through the complete tree visiting all nodes once.
Please help,
Thanks
Sam

That is not a tree;Does it matter? You can always traverse a DAG as a
tree can't you? The A in DAG means acyclic so a DAG
is always also a tree.Check the definitions before you reply please: a DAG
is not "aways also" a tree; no discussion about it. Don't confuse
matters.Who's confusing matters? You introduced the DAG so
you explain why and what consequences it has!No, I just gave a name to what the OP said: s/he didn't show a tree,
s/he showed a DAG; that's all I did.
So a DAG can not always be expanded to a tree? Is that what you're
saying?There's no 'expanding' here; A tree is a very restricted DAG instead.
kind regards,
JosAnd zip up please. Your fake intimacy isn't always wellcome.Stay out of this discussion then; easy as that: a) you lack the knowledge
to participate in this discussion and b) you don't like my friendly greetings,
so the best thing for you, and for this discussion, is that you stay out of it.
kind regards,
Jos

Binary search tree in java using a 2-d array

Good day, i have been wrestling with this here question.
i think it does not get any harder than this. What i have done so far is shown at the bottom.
We want to use both Binary Search Tree and Single Linked lists data structures to store a text. Chaining
techniques are used to store the lines of the text in which a word appears. Each node of the binary search
tree contains four fields :
(i) Word
(ii) A pointer pointing to all the lines word appears in
(iii) A pointer pointing to the subtree(left) containing all the words that appears in the text and are
predecessors of word in lexicographic order.
(iv) A pointer pointing to the subtree(right) containing all the words that appears in the text and are
successors of word in lexicographic order.
Given the following incomplete Java classes BinSrchTreeWordNode, TreeText, you are asked to complete
three methods, InsertionBinSrchTree, CreateBinSrchTree and LinesWordInBinSrchTree. For
simplicity we assume that the text is stored in a 2D array, a row of the array represents a line of the text.
Each element in the single linked list is represented by a LineNode that contains a field Line which represents a line in which the word appears, a field next which contains the address of a LineNode representing the next line in which the word appears.
public class TreeText{
BinSrchTreeWordNode RootText = null;// pointer to the root of the tree
String TextID; // Text Identification
TreeText(String tID){TextID = tID;}
void CreateBinSrchTree (TEXT text){...}
void LinesWordInBinSrchTree(BinSrchTreeWordNode Node){...}
public static void main(String[] args)
TEXT univ = new TEXT(6,4);
univ.textcont[0][0] = "Ukzn"; univ.textcont[0][1] ="Uct";
univ.textcont[0][2] ="Wits";univ.textcont[0][3] ="Rhodes";
univ.textcont[1][0] = "stellenbosch";
univ.textcont[1][1] ="FreeState";
univ.textcont[1][2] ="Johannesburg";
univ.textcont[1][3] = "Pretoria" ;
univ.textcont[2][0] ="Zululand";univ.textcont[2][1] ="NorthWest";
univ.textcont[2][2] ="Limpopo";univ.textcont[2][3] ="Wsu";
univ.textcont[3][0] ="NorthWest";univ.textcont[3][1] ="Limpopo";
univ.textcont[3][2] ="Uct";univ.textcont[3][3] ="Ukzn";
univ.textcont[4][0] ="Mit";univ.textcont[4][1] ="Havard";
univ.textcont[4][2] ="Michigan";univ.textcont[4][3] ="Juissieu";
univ.textcont[5][0] ="Cut";univ.textcont[5][1] ="Nmmu";
univ.textcont[5][2] ="ManTech";univ.textcont[5][3] ="Oxford";
// create a binary search tree (universities)
// and insert words of text univ in it
TreeText universities = new TreeText("Universities");
universities.CreateBinSrchTree(univ);
// List words Universities trees with their lines of appearance
System.out.println();
System.out.println(universities.TextID);
System.out.println();
universities.LinesWordInBinSrchTree(universities.RootText);
public class BinSrchTreeWordNode {
BinSrchTreeWordNode LeftTree = null; // precedent words
String word;
LineNode NextLineNode = null; // next line in
// which word appears
BinSrchTreeWordNode RightTree = null; // following words
BinSrchTreeWordNode(String WordValue)
{word = WordValue;} // creates a new node
BinSrchTreeWordNode InsertionBinSrchTree
(String w, int line, BinSrchTreeWordNode bst)
public class LineNode{
int Line; // line in which the word appears
LineNode next = null;
public class TEXT{
int NBRLINES ; // number of lines
int NBRCOLS; // number of columns
String [][] textcont; // text content
TEXT(int nl, int nc){textcont = new String[nl][nc];}
The method InsertionBinSrchTree inserts a word (w) in the Binary search tree. The method Create-
BinSrchTree creates a binary search tree by repeated calls to InsertionBinSrchTree to insert elements
of text. The method LinesWordInBinSrchTree traverses the Binary search tree inorder and displays the
words with the lines in which each appears.
>>>>>>>>>>>>>>>>>>>>>>
//InsertionBinTree is of type BinSearchTreeWordNode
BinSrchTreeWordNode InsertionBinSrchTree(String w, int line,                                             BinSrchTreeWordNode bst)
//First a check must be made to make sure that we are not trying to //insert a word into an empty tree. If tree is empty we just create a //new node.
     If (bst == NULL)
               System.out.println(Tree was empty)
     For (int rows =0; rows <= 6; rows++)
               For (int cols = 0; cols <= 4; cols++)
                    Textcont[i][j] = w

What is the purpose of this thread? You are yet to ask a question... Such a waste of time...
For future reference use CODE TAGS when posting code in a thread.
But again have a think about how to convey a question to others instead of blabbering on about nothing.
i think it does not get any harder than this.What is so difficult to understand. Google an implementation of a binary tree using a single array. Then you can integrate this into the required 2-dimension array for your linked list implemented as an array in your 2-d array.
Mel

Implementation of LISP trees in Java

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