java - DoubleLinkedList 从节点获取数据

Question

我创建了一个双向链表，并且尝试从链表调用 getData 方法。但是它不起作用。我正在尝试从节点获取此信息。这是来自节点的代码。

    private class Node<AnyType> 
{

    AnyType data;
    Node<AnyType> next;
    Node<AnyType> previous;

    //Creates the Node with the parameters of data next and previous
    public Node(AnyType data,Node<AnyType> next, Node<AnyType> previous )
    {

        this.data = data;
        this.next = next;
        this.previous = previous;

    }

    //Getters and setters for data next and previous
    public AnyType getData() {
        return data;
    }

    public Node<AnyType> getNext() {
        return next;
    }

    public Node<AnyType> getPrevious() {
        return previous;
    }

    public void setData(AnyType data) {
        this.data = data;
    }

    public void setNext(Node<AnyType> next) {
        this.next = next;
    }

    public void setPrevious(Node<AnyType> previous) {
        this.previous = previous;
    }
}

它说 setData(AnyType data) 从未在本地使用，这可能是一个问题，但我对此不确定。

现在我尝试使用 getData 方法。这是在动画方法中，

    if (USE_LINKED_LIST)
    {
        for (int i = 0; i < this.linked_list.size(); i++)
        {
            Movable current = this.linked_list.getData();
            current.move(frame_rate_duration);

            if(current.dead())
            {
                this.linked_list.remove(current);
                i--;
            }

        }
    }

this.linked_list.getData() 给我一个错误，说我必须在 DoublyLinkedList 中创建方法 getData()。我确信这只是一个简单的错误，但任何事情都有帮助!谢谢!

这是整个 LinkedList 类

package Our_Fireworks;

/**
* 
* @author Ben Hammond
*
* @param <AnyType>
*/


public class DoublyLinkedList <AnyType>
{
private Node<AnyType> header;
private Node<AnyType> footer;

public DoublyLinkedList() 
{
    //Creates the header Node with data set to null, next set to footer, previous set to null
    header = new Node<AnyType>(null, footer, null);

    footer = new Node<AnyType>(null, null, header);


}

// Creates the insert method used to insert a Node into the linked list
public void insert(AnyType data)
{
    //Creates a new node to insert before the footer
    Node<AnyType> newNode = new Node<AnyType>(data, footer, footer.previous);
    //Sets the node previous to footer, to link to the new Node
    footer.previous.setNext(newNode);
    //Sets the footer node to be linked to the new Node
    footer.setPrevious(newNode);
}

//Remove method to remove a Node from the linked list
public void remove (AnyType data)
{
    //Starts the iteratorLooper from the first Node in the list
    Iterator<AnyType> iteratorLooper = first();

    //Runs the while loop as long as valid = true 
    while(iteratorLooper.valid())
    {
        //Once you receive the correct data, the loop will stop
        if(iteratorLooper.getData().equals(data))
        {
            break;
        }
        //Goes to the next data member 
        iteratorLooper.next();
    }

    //Once the while loop breaks, it will delete that data member
    iteratorLooper.remove();

}

//Creates the size method
public int size()
{
    //Creates an int variable
    int count = 0;
    //Starts the iteratorLooper at the first Node
    Iterator<AnyType> iteratorLooper = first();

    //As long as valid returns true the while loop will run
    while(iteratorLooper.valid())
    {
        //Will add to the count variable
        count++;
        //Goes to the next Node
        iteratorLooper.next();
    }
    //Returns the count once the while loop is complete
    return count;

}

//Creates the first method
public Iterator<AnyType> first()
{
    //Creates a new Iterator, at header.next
    Iterator<AnyType> newIterator = new Iterator<AnyType>(header.next);
    //Returns the Iterator
    return newIterator;
}
//Creates the last method
public Iterator<AnyType> last()
{
    //Creates a new Iterator at footer.previous
    Iterator<AnyType> newIterator = new Iterator<AnyType>(footer.previous);
    //Returns the Iterator
    return newIterator;
}

//Iterator find method
public Iterator<AnyType> find(AnyType data)
{

    Iterator<AnyType> iteratorLooper = first();
    //As long as valid returns true the while loop runs
    while(iteratorLooper.valid())
    {
        //runs the loop until data is equal to "getData"
        if(iteratorLooper.getData().equals(data))
        {
            break;
        }

        iteratorLooper.next();
    }

    //Returns iteratorLooper
    return iteratorLooper;




}

//Creates the Node class
private class Node<AnyType> 
{

    AnyType data;
    Node<AnyType> next;
    Node<AnyType> previous;

    //Creates the Node with the parameters of data next and previous
    public Node(AnyType data,Node<AnyType> next, Node<AnyType> previous )
    {

        this.data = data;
        this.next = next;
        this.previous = previous;

    }

    //Getters and setters for data next and previous
    public AnyType getData() {
        return data;
    }

    public Node<AnyType> getNext() {
        return next;
    }

    public Node<AnyType> getPrevious() {
        return previous;
    }

    public void setData(AnyType data) {
        this.data = data;
    }

    public void setNext(Node<AnyType> next) {
        this.next = next;
    }

    public void setPrevious(Node<AnyType> previous) {
        this.previous = previous;
    }
}


//Creates the Iterator class
public class Iterator<AnyType>
{
    //Creates a new node of currentNode
    private Node<AnyType> currentNode;

    public Iterator(Node<AnyType> currentNode)
    {
        this.currentNode = currentNode;
    }

    //Creates the valid method
    public boolean valid()
    {
        //Checks to see if current node is not equal to the header footer, or null
        if (currentNode != header && currentNode != footer && currentNode != null)
                {
                    //If the statement is true it returns true
                    return true;

                }
        else
                {
                    //If it is not true... it simply returns false
                    return false;
                }

    }
    //Creates the next method
    public void next()
    {
        //Checks if the next Node is not equal to null
        if(currentNode.getNext() != null)
        {
            //Gets the next node, of what ever the current node is
        currentNode = currentNode.getNext();    
        }
    }
    //Creates the previous method
    public void previous()
    {
        //Checks if the previous Node is not equal to null
        if(currentNode.getPrevious() != null)
        {
            //Gets the previous node of currentNode
            currentNode = currentNode.getPrevious();
        }
    }

    public AnyType getData()
    {
        //Gets the data inside the currentNode
        return currentNode.getData();
    }

    //Creates the remove method
    public void remove()
    {
        //As long as valid returns true than the if statement will run
        if(valid())
        {
        currentNode.getPrevious().setNext(currentNode.getNext());

        currentNode.getNext().setPrevious(currentNode.getPrevious());
        currentNode = currentNode.getPrevious();
        }


    }

    //Creates the insert method with the parameters of AnyType and data
    public void insert(AnyType data)
    {
        //Creates a newNode to be inserted after currentNode
        Node<AnyType> newNode = new Node<AnyType>(data, currentNode.next, currentNode );


        currentNode.getNext().setPrevious(newNode);
        currentNode.setNext(newNode);

    }

   }










    }

Answer 1

您有 Node 的 getData() 方法，而不是您的链表类。我认为你的意思是这样的

Movable current = this.linked_list.get(i).getData();

(假设你的链表类有索引的 getter)

通常链接列表没有随机访问 getter，因此很可能整个代码应该以不同的方式编写:

for (Node<Movable> node = linked_list.getHead(); node != null; node = node.getNext()) {
    Movable current = node.getData();
    ...
}

编辑:所以你的迭代器中有getData():

for (Iterator<Movable> iter = linked_list.first(); iter.valid(); iter.next()) {
    Movable current = iter.getData();
    ...
}