Friday, August 31, 2007


In my previous post on the problems with GTD, I mentioned a bit about using emacs' org-mode to implement a GTD-like system. I've been using it for a while now, with good success.

I've previously used kGTD, as well as iGTD, but I like org-mode the best. With any other application, you are quite limited in what you can do. You can basically do what they want you to, maybe modulo a few scripts or preferences. With org-mode, the basic functionality is extremely flexible, and since it's all just a bunch of lisp code, you can rewrite and alter it to your heart's content.

org-mode, at it's simplest, presents an outline. You can expand and collapse it. Like other programs, you can put all sorts of stuff in the outline, in a very natural matter. For example:

* Fix bug 1919
** Reproduce the bug
This only breaks for very old users
** Write test case for bug
The stars here represent the indentation level. It's all just text, folks. This is emacs, what else would you expect? But notice that I can just add random text anywhere. It will be collapsed along with the "Reproduce the bug" header. This is very convenient place to put notes when you are working. As other programs do, you can have links. When I write "Fix bug 1919", the "1919" can link to my work's bug tracking system. More impressively, this being emacs, I can link to a specific location in a buffer. Opening it takes me right there, and off I go to do whatever work I need to.

I also use TODO tags, which are states associated with each work item. So, if this is an item that can become, in the GTD sense, a "next action", then it has a tag. There are four tags I use:
  1. TODO: An item which is still to be done, but is not yet actionable.
  2. NEXT: A "next action", which should be done.
  3. WAITING: An action that is waiting on some outside signal to either go back to NEXT or DONE.
  4. DONE: Finished. Hooray!

So, the above outline is more like:

* Fix bug 1919
** NEXT Reproduce the bug
This only breaks for very old users
** TODO Write test case for bug

Here is some customization code to enable this, as well as to enable useful agenda commands:

(setq org-todo-keywords '("TODO" "NEXT" "WAITING" "DONE"))
(setq org-agenda-custom-commands
'(("w" todo "WAITING" nil)
("n" todo "NEXT" nil)))

I like to, with one keystroke, mark an entry done and change the next one to NEXT. I wrote the following lisp code to do it:

(defun ash-org-todo-item-p ()
(looking-at "\\*+[ \t]+TODO\\>")))

(defun ash-org-mark-done ()
;; org-entry-is-done-p has a bug where if you are at the first
;; char of a line it doesn't always work. Let's work around it
;; here.
(when (not (org-entry-is-done-p))
(org-todo 'done)
(outline-forward-same-level 1)
(when (ash-org-todo-item-p)
(org-todo "NEXT")))))

(define-key global-map "\C-c\C-x\C-c" 'ash-org-mark-done)

The preceding code gives me a pretty nice, basic GTD system. On top of this I've been adding my own tweaks. One thing I like to do is to keep track of what I'm working on at the current time. This helps me keep focused. Org-mode has a way for keeping track of what you are doing at any one time, which is a clock which you can start or stop on any particular entry. Using this as a basis, I wrote the following nifty function for binding the F9 key to go back to the last current item. I know an item is current if I use the clock-in feature.

(defvar ash-org-current-task-loc nil
"A cons of the buffer & location of the current task")

(defadvice org-clock-in (after ash-org-mark-task activate)
"When the user clocks in, bind F9 to go back to the worked on task."

(setq ash-org-current-task-loc (cons (current-buffer)
(define-key global-map [f9] (lambda ()
(car ash-org-current-task-loc))
(cdr ash-org-current-task-loc)))))

This helps me mark a task as complete, I just hit F9, then C-c C-x C-c, which closes it out (stopping the clock and printing elapsed time), and marks the next item done. Pretty nifty!

This isn't enough, yet. I'm still tweaking the system, trying to perfect it to suit the particular problems I have. I may post more on this in the future.

Saturday, August 04, 2007

The problem with GTD

David Allen's productivity system, GTD (standing for Getting Things Done), continues to be more and more popular. If you are all at interested in being more productive, than likely you've heard of this already. I follow it myself, using emacs and org-mode.  Well, actually, when I say I follow it, I currently only follow part of it, because part of it is just not useful.

There are a few key concepts in GTD, but the most often applied are next actions, contexts, and weekly reviews.   I think that next actions are an important concept.  The general idea is that in your todo list you break down tasks to a level that each are simple and directly actionable with no planning or meta-level thinking required.  One of these is your next action, which is the very next thing you have to do to move your project forward.   This is a cool thing, because it forces your tasks to be of the correct granularity.  Also, most GTD software will show you all your next actions, so that you can see what you have to work on.  Once you complete one next action, the next todo item will become a next action. For example, if your project is to fix a bug, then the next action here is to attempt to reproduce the problem locally.

Actually, this concept is slightly simplistic.  Sometimes your project can have several next actions.  If your project is to launch a new feature, then you might have several next actions, one to write the introduction and high level overview of a design document, the other is to send out a mail to your manager asking who could possibly be allocated to work on this feature.  A good GTD system should let you mark items as next actions arbitrarily.  org-mode does this, which is one of the reasons I like it.

Another key concept of GTD is the weekly review, which means that you update your tasks and take time to plan new ones.  Good advice.  I have nothing to add to it.

Finally, GTD has the notion of contexts, which are the bread-and-butter of most GTD apps.   Contexts represent some state in which your actions are performed.  One obvious place for contexts is for direct communication with someone.  You might have several projects that have an action that requires you to talk to your project manager.  You can associate those tasks with a context, and now you have a context that you look at to before you go speak to the project manager, to see all the appropriate tasks.  Then when you go talk with them, you have a list of things to ask them.

Sounds vaguely useful.  And that's the problem.  For software engineers and other types of knowledge workers, we just don't have a lot of context.   We are pretty well connected.  Usually things that can be done at work in front of our workstation can also be done at home, through VPN.   I find that most of my actions are to be done in front of my workstation, so the vast majority of my tasks have the context of the workstation.  What I find useful is to not use contexts for these tasks, since they all have a default obvious context.  I use it only for person-related contexts (such as the context for my project manager in my example).  And even then it's only somewhat useful.  It's possible that I could start doing work on my subway ride, in which case that is a useful context.  The problem would be that things done on the subway is a subset of things I can do at work.  Here again the concept of rigid contexts doesn't work.   So when I'm at my workstation, every task if fair game.  If I'm somewhere specialized, a specific context may come in handy.   But, ultimately, for most modern "knowledge-workers", contexts are not something we should be spending a lot of time thinking about.

With contexts, org-mode again comes in handy.  It's not a real GTD app, so it doesn't insist on contexts.  It just lets you tag items, and those tags are your contexts.  So you can put things in multiple contexts, or none.  The tags inherit.  I think it's really perfect flexible solution for the modern GTD user.  Next post I'll detail exactly how I use it and give some customizations.

Wednesday, July 04, 2007


In my last post, I discussed annotations, and their contributions to the Java language. The short version: they are pretty simple, and surprisingly useful. Generics, also introduced with Java 1.5, is a much larger pill to swallow. Not on the useful part, they are undeniably helpful. They do something very important, which is to make run-time errors visible at compile time, while at the same time increasing the self-documentation of code. This is a great thing. However, there is no doubt that they add complexity. To even document all cases of complexity would take a whole blog dedicated to just that subject. I'll give one example:

foo(List<B> list);
bar(List<? extends B> list);
tor(List<? super B> list);
So, what's the difference between these? Well, suppose B has a subtype C, and a supertype A. So the inheritance hierarchy goes A -> B -> C. You can call foo with a List<B>, but not a List<C>. But you can call bar with a List<C>; as well as List<B>. You can call tor with a List<A> and List<B>. Keep in mind that the contents of the list are not what I am talking about, just the compile-time type of the list.

Generics are a bit more complicated than most people assume. Almost anyone who has spent time with Generics has gotten into several puzzling situations that they can't explain, and where the solution isn't obvious.

The question I wonder about is whether it has done more harm than good. This is not a matter of opinion, I think. If we could count up all the hours of lost productivity in wrestling with generics, and count the hours saved by catching bugs and improving the clarity of the code, would the time saved exceed the time lost? My anecdotal evidence is that it is a net benefit. It has rescued the Java world from the perils of type-casting, and I do remember getting many ClassCastExceptions in the past. Nowadays they are rare, and I don't spend excessive time on the complexities.

Tuesday, February 13, 2007


This post is a few years too late. Annotations came out in Java 1.5, and we already are on Java 1.6. But I'd like to make a few comments on them, because I think they are a great example of a low-cost but a high-use feature.

Making improvements to a popular language is always difficult. You want each addition in functionality to be well worth it. Each addition should make things possible that were not possible before, and do so in a way that both fits with the spirit of the language, and results in the least possible disruption.

Java annotations are a good example of a good change. I find I use them more and more, and they enable things I now realize I in fact need. Did I need them before annotations were around? It didn't seem so, but now they are here I would find it difficult to live without them.

I should illustrate how useful they are with a made-up example. Let's say you want a simple webserver, one that took the path and used it to call into a dispatcher object. So you would call http://localhost/doSomething?foo=aaa&bar=bbb. This would use Java reflection to call a method Dispatcher.doSomething(String foo, String bar) . But at reflection time you don't know the names of arguments, since those are all compiled away. So, the first challenge is to figure out which argument is foo and which is bar. How can we do this? Before annotations, I would say you cannot do this. You could do something such as populate a String to String map, and pass that in instead of arguments, but this is awkward for the non-reflection callers, and also doesn't enforce important invariants at compile-time. Luckily for us, we do have annotations, and the annotations stick around at runtime (if you want them to). So, we can make an annotation defined as:

import java.lang.annotation.*;

public @interface ParameterName {
String value();

And we can use it like so:

void doSomething(@ParameterName("foo") String foo,
@ParameterName("bar") String bar) {

Now reflection can match HTTP parameters up to the method arguments.

But the fun doesn't stop there. What if you wanted your delegator class to only have some methods accessible from the web? You could try to separate into another class that is only web methods, but that overly constraining on the design. Or, you could maintain a separate list of web-safe methods in a configuration file. That solution seems prone to mistakes - developers will forget to update the configuration file, then wonder why their new method isn't accessible. However, with annotations, you can simply tag methods with an annotation showing that they are web-safe. We can create a runtime method-level annotation called WebExecutable and use it like so:

void doSomething(@ParameterName("foo") String foo,
@ParameterName("bar") String bar) {

Now, your dispatcher can check for the annotation before it executes. Instant safety! You can imagine further annotations that may classify whether methods needs authentication or not, or other such improvements.

I've really been digging annotations. They make things possible that never were possible before, and don't introduce much complexity or confusion. There is some new syntax to learn, and some non-obvious things (such as "@interface"), but all in all, the part you have to look at the most is very easy and intuitive. I think it's an ideal addition to the language.

Next, I intend to look at generics, which has quite a different profile.