Trying to write priority queue in Java but getting "Exception in thread "main" java.lang.ClassCastEx

Posted by Dan on Stack Overflow See other posts from Stack Overflow or by Dan
Published on 2010-05-31T06:37:00Z Indexed on 2010/05/31 6:42 UTC
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For my data structure class, I am trying to write a program that simulates a car wash and I want to give fancy cars a higher priority than regular ones using a priority queue. The problem I am having has something to do with Java not being able to type cast "Object" as an "ArrayQueue" (a simple FIFO implementation). What am I doing wrong and how can I fix it?

public class PriorityQueue<E>
{

    private ArrayQueue<E>[] queues;
    private int highest=0;
    private int manyItems=0;


    public PriorityQueue(int h)
    {
        highest=h;
        queues = (ArrayQueue[]) new Object[highest+1];   <----problem is here
    }


    public void add(E item, int priority)
    {
        queues[priority].add(item);
        manyItems++;
    }


    public boolean isEmpty( )
    {
        return (manyItems == 0);
    }


    public E remove()
    {
        E answer=null;
        int counter=0;

        do
        {
            if(!queues[highest-counter].isEmpty())
            {
                answer = queues[highest-counter].remove();
                counter=highest+1;
            }
            else
                counter++;
        }while(highest-counter>=0);

        return answer;
    }
}

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