import java.io.IOException;
import java.lang.ArrayIndexOutOfBoundsException;
import java.lang.NumberFormatException;
import java.util.Vector;
import rebelsky.io.SimpleReader;
import rebelsky.io.SimpleOutput;
import rebelsky.util.NumberRangeException;

/**
 * Allow interactive testing of the <code>java.util.Vector</code>.
 * Used to extend understanding of what that class does in various
 * situations.
 * 
 * @author Samuel A. Rebelsky
 * @author YOUR NAME HERE
 * @version 1.0 of February 1998
 */
public class VectorTester 
{
  // +------------+---------------------------------------------------------
  // | Attributes |
  // +------------+

  /**
   * The object used for output.
   */
  protected SimpleOutput out;
  
  /**
   * The object used for input.
   */
  protected SimpleReader in;

  /**
   * The vector we're testing.
   */
  protected Vector vec;


  // +--------------+-------------------------------------------------------
  // | Constructors |
  // +--------------+

  /**
   * Build a new tester.  
   */
  public VectorTester()
  {
    in = new SimpleReader();
    out = new SimpleOutput();
    vec = new Vector();
  } // VectorTester()


  // +---------+------------------------------------------------------------
  // | Methods |
  // +---------+

  /**
   * Append an element to the current vector.
   */
  public void append(String val) 
  {
    vec.addElement(val);
  } // append(String)

  /**
   * Look up a value.
   */
  public void lookup(int pos)
  {
    try {
      out.println(pos + ": " + vec.elementAt(pos));
    }
    catch (ArrayIndexOutOfBoundsException e) {
      out.println(pos + " is an invalid position");
    }
  } // lookup(int)

  /**
   * Give instructions for using this program.
   */
  public void giveHelp()
  {
    out.println("a val  append a value");
    out.println("h      get this help message");
    out.println("l pos  look up the value at position pos");
    out.println("p      print the current vector");
    out.println("q      quit");
  } // giveHelp()

  /**
   * Print the current vector.
   */
  public void print()
  {
    out.println(vec.toString());
  } // print()


  // +------------+---------------------------------------------------------
  // | Attributes |
  // +------------+

  /**
   * Repeatedly prompt for what to do and then do it.
   */
  public static void main(String[] args)
  {
    // The object used to drive the testing
    VectorTester tester = new VectorTester();
    // The base part of the user's response
    String resp;
    // The value the user wants to add or retrieve
    String val;
    // The index the user wants to use
    int index;

    // Provide some basic instructions
    tester.giveHelp();

    // Keep going until we hit the end of file or the user quits.
    // One exit is done using "break", and the other is done using
    // a catch of the end-of-file exception, so it looks as if our
    // loop continues indefinitely.
    try {
      LOOP:
      while (true)
      {
        // Print a prompt
        tester.out.println();
        tester.out.print("> ");
        // Get the first response
        resp = tester.in.readString();
        // Make sure the response is non-empty
        if (resp.length() == 0) {
          tester.out.println("You must give a non-empty response.");
          tester.giveHelp();
          continue;
        }
        // Determine what to do based on the first character
        switch (resp.charAt(0)) {
          case 'a':				// append
            // Get the value and append it
            val = tester.in.readString();
            tester.append(val);
            break;

          case 'h':				// help
            tester.giveHelp();
            break;

          case 'l':				// lookup
            // Get the position and look up
            try {
              index = tester.in.readInt();
              tester.lookup(index);
            }
            catch (NumberFormatException e) {
              tester.out.println("Invalid position");
            }
            catch (NumberRangeException e) {
              tester.out.println("Invalid position");
            }
            break;

          case 'p':				// print
            tester.print();
            break;

          case 'q':				// quit
            break LOOP;
        } // switch
        // Skip anything else on the line
        tester.in.readLine();
      } //while
    } // try doing the input
    catch (IOException e) {
      // We're done
    } // catch(IOException)

  } // main
  
} // VectorTester