/*
 * T03n06.java -- Use DataInputStream to read a binary file of ints
 * The ints will be read from the file created in the previous example.
 * DataInputStream is the counterpart of DataOutputStream, and has an
 * input counterpart to the output methods of DataOutputStream.
 *
 * If you've seen the previous example, the only new thing is the method
 * for computing the number of ints to read from the file; there's a 
 * detailed comment about that in the code.
 */

import java.io.*;

public class T03n06
{
    public static void main (String [] args) 
    {
        final String    fileName = "T03n05.out";
        File            fileRef;
        FileInputStream byteStream;
        DataInputStream intStream = null;
        int[]           scores;
        int             numOfInts;

        System.out.println("Reading an array of ints from the file '"
                       + fileName + "'...");

        try {

            fileRef = new File(fileName);
            byteStream = new FileInputStream(fileRef);
            intStream = new DataInputStream(byteStream);

                /* We have a file the holds only ints, and an int is always
                 * 4 bytes in size.  So, the number of ints that we need
                 * to read (and thus the size of the array) is one-quarter
                 * of the number of bytes in the file.
                 */

            numOfInts = (int) fileRef.length() / 4;   
            scores = new int [numOfInts];

            for (int i = 0; i < numOfInts; i++) {
                scores[i] = intStream.readInt();
            }

            intStream.close();

            System.out.println("Done!  Here are the values we just read:");
            for (int i = 0; i < scores.length; i++) {
                System.out.print(scores[i] + " ");
            }
            System.out.println();

        } catch (IOException e) {

            System.out.println("I/O ERROR:  Something went wrong with the "
                             + "creation of the file of ints,\nbut because "
                             + "some lazy programmer dumped all of the file "
                             + "code into\none try block, I can't be more "
                             + "specific!  Here's what I can tell you:");
            System.out.println("  The Error: " + e.getClass().getName());
            String mesg = e.getMessage();
            if (mesg == null) {
                System.out.println("The message:  None.");
            } else {
                System.out.println("The message: " + mesg);
            }
            System.out.println("The stack trace:");
            e.printStackTrace();

        }
    }
}