on calling methods..

[marc perry batuigas]

it's me again... er, still got a question to ask bout my last program, this time it concerns calling methods...well in my program (MyLinkedList), i used bufferedreader to read the text file, then put it again on StrongTokenizer to read each character of the text file, in a line...assuming i have already initialized the linkedlist into my main and bufferedReader has read the file, and stringTokenizer is reading a line, i want to call, say, remove, how do i call the methods while still in the stringTokenizer?
really need some answers guys, this is my 2nd year as BSIT, and i'm doing my best to love java...and MyLinkedList is just one of the three of my school projects. hope to hear from someone soon...

[Mike Gershman]

Please post the code you have so far. Be sure to use the code button to create code tags so your indentation is preserved.

[marc perry batuigas]

 import java.io.*;
import java.util.*;
class Item
{
  public Item( Object d, Item n )
  {
  data = d;
  next = n;
  }
  public Object data;
  public Item next;
}
class MyLinkedList
{
  private Item head;
  private Item tail;
//head is the first element in the list.
//tail is the last element in the list.
public MyLinkedList()
{
  head = null;
  tail = null;
}
public void addTail( Object data )
{
  Item newTail = new Item( data, null );
  if( head == null )
  {
    head = newTail;
    tail = head;
  }
  else
  {
  tail.next = newTail;
  tail = newTail;
  }
}
public void addHead( Object data )
{
  Item newHead = new Item( data, head );
  if( head != null )
    head = newHead;
  else
  {
    head = newHead;
    tail = head;
  } 
}
public void add( Object data, int index )
{
  if( ( index == 0 ) || ( head == null ) )
  addHead( data );
  else
  {
    Item current = head;
    while( ( current != null ) && ( index > 1 ) )
    {
      current = current.next;
      index--;
    }
    if( current != null )
    {
      current.next = new Item( data, current.next );
      if( current == tail )
      tail = current.next;
    }
  }
}
public Object removeHead()
{
  if( head == null )
    return null;
  Object data = head.data;
  head = head.next;
  return data;
}
public int find( Object data )
{
  if( head == null )
    return -1;
  int index = 0;
  Item current = head;
  while( ( current != null ) && ( !current.data.equals( data ) ) )
  {
    index++;
    current = current.next;
  }
  if( current == null )
    return -1;
  else
  return index;
}
public Object remove( int index )
{
  if( index == 0 )
  return removeHead();
  if( head == null )
  return null;
  Item current = head, previous = null;
  while( ( current != null ) && ( index > 0 ) )
  {
    previous = current;
    current = current.next;
    index--;
  }
  if( current == null )
  return null;
  Object data = current.data;
  previous.next = current.next;
  return data;
} 
public String toString()
{
  if( head == null )
    return "<empty>";
  Item current = head;
  String res = "{";
  while( current != null )
  {
    res = res + current.data;
    if( current.next != null )
      res += ",";
      current = current.next;
  }
    res += "}";
    return res;
}
public static void main( String args[] ) 
{
  System.out.println("Enter file name:");
  String fileName = SavitchIn.readLine();
try
{
  BufferedReader inputStream = 
  new BufferedReader(new FileReader(fileName));
  String line;
  while((line = inputStream.readLine()) != null)// thanks to tom blough
  {
    line = inputStream.readLine();
    StringTokenizer inputReader = new StringTokenizer(line);
    while(inputReader.hasMoreElements())
    {
      Object n = inputReader.nextElement();
      if (n.equals("d"))
      { 
        Object x = inputReader.nextElement();
        //System.out.println("element " + x + " is removed");
      }
      else if(n.equals("i"))
      {
        Object y = inputReader.nextElement();
        if(inputReader.hasMoreElements())
        {
          Object y1 = inputReader.nextElement(); 
          //System.out.println("element " + y1 + " is inserted after " + y);
        }
        else;
      }
      else if(n.equals("ie"))
      {
        Object z = inputReader.nextElement();
        //System.out.println("element " + z + " inserted at the end
      else
      {
      boolean finish = false;
      finish = inputReader.hasMoreElements();
      }
    }
  }
    inputStream.close(); 
}
  catch(FileNotFoundException e)
  {
    System.out.println(fileName + " not found!");
  }
  catch(IOException e)
  {
    System.out.println("Error reading" + fileName);
  }

}
}
 

[Stefan Wagner]

How about creating an instance of your MyLinkedList in the main-method?
Than you could use this instance, and add, remove, ...
And I would suggest moving the main-method to a separate class, since your List shouldn't be bundled to a specific usage of it.
[ May 08, 2004: Message edited by: Stefan Wagner ]

[marc perry batuigas]

got the solution already guyz...LOLz
this forum really helped me alot...hope u continue to help others too sa u did for me...thanks a million and more POWER!