Linked list problem

[David Harkness]

It's difficult to tell from your code, but one thing strikes me as incorrect:

public void addKeyword(String newrule) {
    ...
    RuleList rule = new RuleList();
    // (use a method here from RuleList to add to Rule List)
    newNode = new Node(newkey, rule, current);  // Pass in new RuleList with one Rule
    newNode.display();
}
 
Node(String newkey, RuleList rule, Node newLink) {
    keyword = new String(newkey);
    rule = new RuleList();   // Ignore one-Rule RuleList passed in
    occurrences = 1;
    next = newLink;
}

In Node's constructor, you are ignoring the RuleList that was passed in by the addKeyword method, instead creating an empty list and storing that.
[ September 27, 2004: Message edited by: David Harkness ]

[Dominique Ramoney]

Thanks David!!

That's exactly what it is. I was just so tired yesterday and I hadn't used a list as a constructor parameter before, I let common sense slip.



Dominique

[Dominique Ramoney]

Hi

I have a linked list class whose nodes contain a linked list;

I'm doing this like so;

class KeywordList{
private Node head;

public KeywordList() {
head = null;
}

public void addKeyword(String newrule) {
Node current,previous,newNode;
(initialize stuff here)
RuleList rule = new RuleList();
(use a method here from RuleList to add to Rule List)
newNode = new Node(newkey, rule, current);
newNode.display();

}

class Node {
String keyword;
int occurrences;
Node next;
RuleList rule;

Node(String newkey, RuleList rule, Node newLink) {
keyword = new String(newkey);
rule = new RuleList();
occurrences = 1;
next = newLink;
}

public void display(){

RuleList.Iterator RuleRetriever = rule.new Iterator();
System.out.println("Keyword " + keyword);
while (RuleRetriever.hasMoreRules()) {
System.out.print("from display ");
System.out.println(String.valueOf(RuleRetriever.nextItem()));}
}


(methods for Node class follows and Iterator class)

The problem I'm having is that I am unable to access the rule parameter of Node from the display method. My toString method and compareTo method has no problem getting keyword or occurrences but trying to access the rule, yields null.


This is really making my brain bleed. Any help will go long way in avoiding an aneurisym.

Thanks
Dominique

[Vladas Razas]

As much as I would love to help you but your question is not formed well. It has code that do not pertain directly to the question. Please write us what specificaly doesn't work.