Java 绑定(bind)不匹配错误 - LinkedList

Question

好的，这是我正在使用的界面。

/* instance of classes that realize this interface can be compared */

public interface Comparable<E> 
{ 
/* Method to compare this object to the argument object 
* @param obj - the argument object 
 * @return - returns a negative integer if this object < obj 
*/ 
int compareTo(E obj); 

}

然后是有序列表类。

import java.util.*;

/* a class to represent an ordered List. the data is stored
* in a linked list data field
*/
public class OrderedList<E extends Comparable<E>> 
        implements Iterable<E>
{
/* a linked list to contain data */
private LinkedList<E> theList = new LinkedList<E>();

/* Insert Obj into the list preserving the lists order 
 * @param pre - the items in the list ordered
 * @param post - obj has been inserted into the list such 
 * that the items are still in order
 */

public void add(E obj)
{
    ListIterator<E> iter = theList.listIterator();
    // find the insertion position and insert
    while(iter.hasNext())
    {
        if(obj.compareTo(iter.next()) < 0)
        {
        // Iterator has stepped over the first element that 
        // is greater than the element to be inserted 
        // move the iterator back one
        iter.previous();
        // insert the element
        iter.add(obj);
        //exit the loop and return
        return;
        }
    }
    /* assert - all items were examined and no item is larger than 
     * the element to be inserted
     * add the new item to the end of the list 
     */
    iter.add(obj);
}

/* returns the element at the specified position */
public E get(int index)
{
    return theList.get(index);
}

/* returns an iterator to this ordered List */
public Iterator<E> iterator()
{
    return theList.iterator();
}

/* returns the size of the list */
public int size()
{
    return theList.size();
}
}

以及问题所在的测试类。

import java.util.*;

public class TestOrderedList 
{

/* Traverses ordered list and displays each element
 * displays and error message if an element is out of order
 * @param testList - an ordered list of integers
 */

public static void traverseAndShow(OrderedList<Integer> testList)
{
    int prevItem = testList.get(0);

    /* traverse ordered list and display any value that 
     * is out of order
     */
    for(int thisItem : testList)
    {
        System.out.println(thisItem);

        if(prevItem > thisItem)
            System.out.println("***Failed, value is " + thisItem);
        prevItem = thisItem;
    }
}
public static void main(String[] args) 
{
    OrderedList<Integer> testList = new OrderedList<Integer>();
    final int MAX_INT = 500;
    final int START_SIZE = 100;

    // create a random generator
    Random random = new Random();
    for(int i = 0; i < START_SIZE; i++)
    {
        int anInteger = random.nextInt(MAX_INT);
        testList.add(anInteger);
    }

    //Add to beginning and end of list.
    testList.add(-1);
    testList.add(MAX_INT + 1);
    traverseAndShow(testList); // traverse and display 
}
}

当我尝试在测试类中使用 Integer 时，出现“绑定(bind)不匹配”错误。问题出在哪里？

Answer 1

您已经定义了自己的 Comparable 接口(interface)，而 Integer 并未实现该接口(interface)。从构建路径中删除自定义接口(interface)，以便内置 java.lang.Comparable可以用它代替