مسااعده للخبرين في استخدام ال Node

لو ممكن توضح أكثر سيكون أحسن

هل تعني ب Node الكلاس التي توجد في حزمة الDOM ؟؟

وإذا أمكن تعطينا الكود الذي تقوم فيه بالإضافة والذي يعطيك الخطأ

import java.util.*;

public class AList <T> implements ListInterface <T>

{

private Node firstNode; // reference to first node

private int length; // number of entries in list

public AList()

{

clear ();

} // end default constructor

public final void clear ()

{

firstNode = null;

length = 0;

} // end clear

public boolean add (T newEntry)

{

Node newNode = new Node (newEntry);

if ( isEmpty() )

firstNode = newNode;

else // add to end of nonempty list

{

Node lastNode = getNodeAt(length);

lastNode.next = newNode; // make last node reference new node

} // end if

length++;

return true;

} // end add

public boolean add (int newPosition, T newEntry)

{

boolean isSuccessful = true;

if ((newPosition >= 1) && (newPosition <= length + 1))

{

Node newNode = new Node (newEntry);

if (isEmpty () || (newPosition == 1)) // case 1

{

newNode.next = firstNode;

firstNode = newNode;

}

else // case 2: list is not empty

// and newPosition > 1

{

Node nodeBefore = getNodeAt (newPosition - 1);

Node nodeAfter = nodeBefore.next;

newNode.next = nodeAfter;

nodeBefore.next = newNode;

} // end if

length++;

}

else

isSuccessful = false;

return isSuccessful;

} // end add

public void display ()

{

Node currentNode = firstNode;

while (currentNode != null)

{

System.out.println (currentNode.data);

currentNode = currentNode.next;

} // end while

} // end display

public boolean isEmpty ()

{

boolean result;

if (length == 0)

{

assert firstNode == null;

result = true;

}

else

{

assert firstNode != null;

result = false;

} // end if

return result;

} // end isEmpty

public boolean replace (int givenPosition, T newEntry)

{

boolean isSuccessful = true;

if ((givenPosition >= 1) && (givenPosition <= length))

{

assert !isEmpty ();

Node desiredNode = getNodeAt (givenPosition);

desiredNode.data = newEntry;

}

else

isSuccessful = false;

return isSuccessful;

} // end replace

public T getEntry (int givenPosition)

{

T result = null; // result to return

if ((givenPosition >= 1) && (givenPosition <= length))

{

assert !isEmpty ();

result = getNodeAt (givenPosition).data;

} // end if

return result;

} // end getEntry

public T remove (int givenPosition)

{

T result = null; // return value

if ((givenPosition >= 1) && (givenPosition <= length))

{

assert !isEmpty ();

if (givenPosition == 1) // case 1: remove first entry

{

result = firstNode.data; // save entry to be removed

firstNode = firstNode.next;

}

else // case 2: givenPosition > 1

{

Node nodeBefore = getNodeAt (givenPosition - 1);

Node nodeToRemove = nodeBefore.next;

Node nodeAfter = nodeToRemove.next;

nodeBefore.next = nodeAfter; // disconnect the node to be removed

result = nodeToRemove.data; // save entry to be removed

} // end if

length--;

} // end if

return result; // return removed entry, or

// null if operation fails

} // end remove

public boolean isFull () // should ALWAYS return false

{

return false;

}

public int getLength () // should ALWAYS return false

{

return length;

}

public boolean contains (T anEntry)

{

boolean found = false;

Node currentNode = firstNode;

while (!found && (currentNode != null))

{

if (anEntry.equals (currentNode.data))

found = true;

else

currentNode = currentNode.next;

} // end while

return found;

} // end contains

/** Task: Returns a reference to the node at a given position.

* Precondition: List is not empty; 1 <= givenPosition <= length. */

private Node getNodeAt (int givenPosition)

{

assert !isEmpty () &&

(1 <= givenPosition) && (givenPosition <= length);

Node currentNode = firstNode;

// traverse the list to locate the desired node

for (int counter = 1 ; counter < givenPosition ; counter++)

currentNode = currentNode.next;

assert currentNode != null;

return currentNode;

} // end getNodeAt

public static void main (String [] args)

{

ListInterface < String > myList = new AList();

System.out.println ("Add 1: returns " + myList.add ("1"));

System.out.println ("Add 5: returns " + myList.add ("5"));

System.out.println ("Add 9: returns " + myList.add ("9"));

ListInterface < String > myList2 = new AList ();

System.out.println ("Add 2: returns " + myList.add ("2"));

System.out.println ("Add 3: returns " + myList.add ("3"));

System.out.println ("Add 4: returns " + myList.add ("4"));

System.out.println ("Add 6: returns " + myList.add ("6"));

System.out.println ("Add 7: returns " + myList.add ("7"));

System.out.println ("Add 8: returns " + myList.add ("8"));

ListInterface < String > myList3 = new AList ();

int c1,c2 ;

c1 = myList.getEntry() ;

c2 = myList2.getEntry() ;

for (int counter = myList.getLength() ; counter < c2 ; counter++){

if (c1 < c2)

{

myList3.add() = c1;

}

}

} // end main

private class Node // private inner class

{

private T data; // entry in list

private Node next; // link to next node

private Node (T dataPortion)

{

data = dataPortion;

next = null;

} // end constructor

private Node (T dataPortion, Node nextNode)

{

data = dataPortion;

next = nextNode;

} // end constructor

} // end Node

} // end LList

يا أخي هذا طبيعي

<span class="postcolor">ListInterface < String > myList = new AList();</span>

أنت هنا تقول أن myList ستحتوي على عناصر من صنف String، وعندما تقوم بgetEntry فستعيد لك String وليس int

إستعمل Integer بدل String

  //............................