Javelin question with linkedlist

MightyBeast

i want to use linkedlist and i want the value of each node to be a array of char.
can anybody tell me how would i do this?

do i have to write a linkedlist class with add, remove functions, or can i just import it from library

thanks

Peter Verkaik

The stamp.util package has a List object and accompanied methods.
See page 157 and further in the manual.

As an alternative there is my implementation of a heap,·list, stack and queue.
http://tech.groups.yahoo.com/group/JavelinCode/files/Javelin%20Stamp%20IDE/lib/stamp/peripheral/memory/
If your goal is to store your list in an external memory like eeprom, then my
implementation is more suitable because it allows you to add and remove from the list
without copying it back to memory first (which must be when using object references).

regards peter

MightyBeast

Thank you for you help. I need to save the value in the ram, javelin needs to insert and remove constantly.
I have one more question, the add method in the list object take parameter of an object, what can i do to make it takes a string or an array of char?

Thanks

Peter Verkaik

You need to extend the LinkedListItem class (which is an abstract class),
for a String you could define

package stamp.util;
public class StringLinkedListItem extends LinkedListItem {
· private String s = new String();
· public StringLinkedListItem() {
··}

··//example of method for reading a char
· public char charAt(int i) {
··· return s.charAt(i);
· }

}

In your main application program,use
static StringLinkedListItem myItem = new StringLinkedListItem();
You can of course define any datastructure plus methods that you like.
The key is to extend the LinkedListItem class, becaus these objects
can be inserted/removed/added to the LinkedList object.

regards peter

MightyBeast

import stamp.core.*;
import stamp.util.*;

public class ListTest {
static StringLinkedListItem myItem = new StringLinkedListItem();
static LinkedList myList = new LinkedList();
public static void main() {
myItem.addString("Hello World");
myList.addItem(myItem);
System.out.println((myList.getFirst()).getString());
myList.removeItem(myItem);
}
}
class StringLinkedListItem extends LinkedListItem {
private String s = new String();
public StringLinkedListItem() {
}
public void addString(String a)
{
s = a;
}
public String getString()
{
return s;
}
}


In the main method, why it doesnt print the value of the first item? and also if i want to add more strings to the linkedlist, i have to create more StringLinkedListItem objects, and just add to the same list right?

Peter Verkaik

I put your example code in files and it didn't compile.
So I changed it a little.

Here is the application file

import stamp.core.*;
import stamp.util.*;
public class LinkedListTest {
· static StringLinkedListItem myItem = new StringLinkedListItem();
· static LinkedList myList = new LinkedList();
· static StringLinkedListItem k;
· public static void main() {
··· myItem.addString("Hello World");
··· myList.addItem(myItem);
··· k = (StringLinkedListItem)myList.getFirst();
··· System.out.println(k.getString());
··· myList.removeItem(myItem);
· }
}

Notice that I cast LinkedListItem to StringLinkedListItem.
That is required because LinkedListItem does not have a getString() method.
To add more items to the list, you must indeed first create more StringLinkedListItem objects.

regards peter

MightyBeast

Peter:

Thanks a lot for your help. because of that, i was able to make a progress on my project.

thanks again