Overall description of the project, that includes a brief description of the List ADT. please put in paragraph form

what to do for the project

Design, implement and test a List ADT implementation based on a doubly linked list that uses the authors' DLLNode object (found in the support folder). In addition to the authors' standard list operations , your class must support backward iteration through the list via resetBack and getPrevious methods. The authors suggest including an instance variable that always references the last element on the list. Consider the remove operation for a doubly linked list and design and create the code for remove. Remember to handle all of the special cases.

DLLNode.JAVA

package ddladt;

public class DLLNode

{

private DLLNode next,back;

private T info;

public DLLNode(T info)

{

this.info = info;

next = null;

}

public void setInfo(T info)

{

this.info = info;

}

public T getInfo()

{

return info;

}

public void setNext(DLLNode next)

{

this.next = next;

}

public DLLNode returnNext()

// Returns next link of this DLLNode.

{

return next;

}

public void setBack(DLLNode back)

{

this.back = back;

}

public DLLNode getBack()

{

return back;

}

}

DLLAdt.JAVA

package ddladt;

public class DLLAdt

{

protected int elemNum;

protected DLLNode current;

protected DLLNode backCurrent;

protected boolean status;

protected DLLNode pos;

protected DLLNode backe;

protected DLLNode dlList;

protected DLLNode end;

//class constructor

public DLLAdt()

{

elemNum = 0;

dlList = null;

end = null;

current = null;

backCurrent = null;

}

//to insert to dd list

public void add(T element)

{

DLLNode newNode = new DLLNode(element);

if(dlList==null)

{

dlList = newNode;

end = dlList;

}

else

{

dlList.setBack(newNode);

newNode.setNext(dlList);

dlList = newNode;

}

elemNum++;

}

protected void find(T target)

{

pos = dlList;

status = false;

while (pos != null)

{

if (pos.getInfo().equals(target))

{

status = true;

return;

}

else

{

backe = pos;

pos = pos.returnNext();

}

}

}

//to get the size

public int size()

{

return elemNum;

}

//to check the presence of an entry

public boolean contains (T element)

{

find(element);

return status;

}

//to delete entries from the list

public boolean delete (T element)

{

find(element);

if (status)

{

if (dlList == pos)

dlList = dlList.returnNext();

else

backe.setNext(pos.returnNext());

elemNum--;

}

return status;

}

public T get(T element)

{

find(element);

if (status)

return pos.getInfo();

else

return null;

}

public String toString()

{

DLLNode currNode = dlList;

String listString = "List: ";

while (currNode != null)

{

listString = listString + " " + currNode.getInfo() + " ";

currNode = currNode.returnNext();

}

return listString;

}

//reset teh list

public void reset()

{

current = dlList;

}

public void backReset()

{

backCurrent = end;

}

public T returnNext()

{

T next = current.getInfo();

if (current.returnNext() == null)

current = dlList;

else

current = current.returnNext();

return next;

}

//get previous

public T getPrevious()

{

T pre = backCurrent.getInfo();

if (backCurrent.getBack() == dlList)

backCurrent = end;

else

backCurrent = backCurrent.getBack();

return pre;

}

}

Test.JAVA

package ddladt;

//The driver program

public class Test

{

public static void main(String args[])

{

DLLAdt dlList= new DLLAdt();

for(int itr=100;itr>1;itr-=10)

dlList.add(itr);

System.out.println(dlList.toString());

dlList.reset();

dlList.backReset();

System.out.println(" Testing the returnNext() function");

System.out.print(" "+dlList.returnNext().intValue());

System.out.print(" "+dlList.returnNext().intValue());

System.out.print(" "+dlList.returnNext().intValue());

System.out.println(" Testing the getPrevious() function");

System.out.print(" "+dlList.getPrevious().intValue());

System.out.print(" "+dlList.getPrevious().intValue());

System.out.print(" "+dlList.getPrevious().intValue());

}

}