Question

I’m using the Arrays.sort method to sort an array of my own Comparable objects. Before I use sort the array is full, but after I sort the array and print it to System nothing is printing out. EDIT. the array prints nothing at all. not empty line(s), just nothing.

here is the code for my method which uses sort :

public LinkedQueue<Print> arraySort(LinkedQueue<Print> queue1)
{
    Print[] thing = new Print[queue1.size()];
    LinkedQueue<Print> newQueue = new LinkedQueue<Print>();

    for(int i = 0; i <queue1.size(); i++)
    {
        Print ob = queue1.dequeue();
        thing[i] = ob;
        System.out.println(thing[i]);   //printing works here
    }

    Arrays.sort(thing);

    for(int j = 0;j<thing.length-1;j++)
    {
        System.out.println(thing[j]);   //printing does not work here 
        newQueue.enqueue(thing[j]);
    }

    return newQueue;
}

and here is the class for the Comparable object called Print.

public class Print implements Comparable<Print>
{
    private String name;
    private int numPages,arrivalTime,startTime,endTime;

    public Print(String n, int p, int time, int sTime, int eTime)
    {
        name = n;
        numPages = p;
        arrivalTime = time;
        startTime = sTime;
        endTime = eTime;
    }

    public int getPages()
    {
        return numPages; 
    }

    public int compareTo(Print other)
    {
        if(this.getPages()<other.getPages())
            return -1;

        else if(this.getPages()>other.getPages())
            return 1;

        else
            return 0;
    }

    public String toString()
    {
        return name+"("+numPages+" pages) - printed "+startTime+"-"+endTime+" minutes";
    }
}

Answer 1

Your last for loop doesn’t print the last element in the array. If the array has only one element, it won’t print anything at all. Change to:

for (int j = 0; j < thing.length; j++) //clean code uses spaces liberally :)
{
    System.out.println(thing[j]);
    newQueue.enqueue(thing[j]);
}

or (if supported by the JDK/JRE version used):

for (Print p : thing)
{
    System.out.println(p); 
    newQueue.enqueue(p);
}