Continue lab partners

Overview

• Preliminaries.
  • Admin.
  • Upcoming Work.
  • Extra Credit.
  • Questions.
• Quick Summary.
• Questions on Anonymous Functions.
• Lab.

Preliminaries

Admin

• Office hours this week (modified due to too-many meetings):
  • Thursday 8:00-9:45, 2:30-3:15
  • Friday 2:15-3:15
• A note from yesterday evening's tutor: "In Java, one student's procedure was throwing an exception, and then apparently continuing on to run the rest of his code anyway. We couldn't figure out why this was happening." Anyone want to talk to me about this?
• I appreciate that I'm teaching anonymous procedures in both 151 and 207 today. I hope that you do, too.
• Review session tomorrow at 11:00; Sam will prob. discuss merge and anything else of interest.
• I'm still willing to accept a new color Scheme for the site, even hideous green colors.

Upcoming Work

• Daily reflection.
• HW 7 assigned. (Not quite ready for prime time.)
  • Finish any part of Assignment 6 you have not yet finished.
  • Do the Ushahidi Lab. You'll only need to turn in Extras 1 and 2.
  • Those last two problems ask you to filter. Write a generalized filter for vectors of Ushahidi Incidents.
  • Write a user interface in which users can select criteria for Ushahidi incidents and print out all of the incidents that meet those criteria.
• Readings for Friday:
  • Anonymous Inner Classes
  • Java Tutorial/Inner Classes: http://docs.oracle.com/javase/tutorial/java/javaOO/innerclasses.html
  • Java Tutorial/Local Classes: http://docs.oracle.com/javase/tutorial/java/javaOO/localclasses.html
  • Java Tutorial/Anonymous Classes: http://docs.oracle.com/javase/tutorial/java/javaOO/anonymousclasses.html

Extra Credit Opportunities

Academic

• CS extras Thursday: Alumni
• CS table Friday: Serendipity and Computing (with Grinnell's Artist in Residence)
• Grinnell Prize Events the following week
• Sign up for the Putnam exam

Peer Support

• Neverland this weekend (7 Friday and Satuday, 2 on Sunday)

Miscellaneous

Questions

Quick Summary of Anonymous Functions

• Lots of situations in which it's nice to be able to write a function (or class) "on the fly".
  • map
  • sort
  • reduce
• How do we do this in Java? Before Java 8, not quite possible, and messy when it was.
• In Java 8, called lambdas.

• Two parts: Functional Interface: Only method

  @FunctionalInterface
  public interface Yeller
  {
    public void yell(Printwriter pen);
  } // interface Yeller
  

• Continuing the example public class YellFire implements Yeller { public void yell(PrintWriter pen) { pen.println("FIRE!"); } }

  Yeller sam = new YellFire();
  yellAtClients(sam);
  
  
  public void yellAtClients(Yeller old)
  {
    for (Client client : clients)
      old.yell(client.pen);
  }
  

• You can write (PARAMS) -> { BODY }

  yellAtClients((pen) -> { String message = "Plesae Disconnect"; pen.println(messeage); });
  

Questions on Anonymous Functions

Lab