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Instant messaging and Yahoo!’s client

Like many folks, I’ve grown to depend on instant messaging (IM–it’s also a verb, to IM is to ‘instant message’), in the workplace. It’s a fantastic technology, but two years ago, I turned up my nose at it. (Of course, 5 years ago, in a similar manner, I turned up my nose at a cell phone, and now I wouldn’t be caught dead without it, so perhaps I’m not the best prognosticator.) What can it possibly offer that email can’t? I’m going to examine it from the perspective of a software developer, since that’s what I know; from that perspective, there are two main benefits IM offers that email doesn’t, timeliness and presence:

I didn’t think it was possible, but email can be too formal at times. When you have a question that needs to be answered right away or it becomes superfluous, IM is perfect. If it’s a question about consistency of API or an area that you know the recipient knows much better than you, sometimes 30 seconds of their time can be worth 15 minutes of yours. Of course, there’s a judgment call to be made; if you’re constantly IMing questions about the API of java.lang.String, you risk breaking up the answerer’s flow. However, used in moderation, it can greatly increase the communication between team members, especially when it’s a distributed team.

Presence is also a huge benefit of most IM software. This means that you have a list of ‘buddies’ that the IM software monitors for you. When each signs on or signs off, you’re made aware of that fact. This means that you can tell whether it’s worthwhile calling someone with a deeper question, or if you should just compose an email. The technical details of presence are being codified at the IETF and I foresee this becoming more and more useful, because it’s a non intrusive way for folks to manage their availability. It fulfills some of the same functions as a ‘door closed/door opened’ policy in an office, extending worldwide.

I use Yahoo IM because it fits my needs. Russell Beattie has recently written an overview of the main competitors and their clients, but technical geegaws like integration with music really don’t matter all that much to me. Much more important are:

1. Does everyone I need to talk to have an account? How easy is it for them to get an account?

2. Does it have message archiving? How searchable are such archives?

3. How stable is the client?

That’s about all I considered. I guess I let my contrarian streak speak too–I’m not a big fan of Microsoft, so I shyed away from Windows Messenger. There are some nice additional features, however. The ability to have a chat session, so that you can IM to more than one person at once, a la IRC, is nice. Grouping your buddies is great–each company I’ve consulted/contracted for has their own group in my IM client. I just discovered these instructions to put presence information on a web page. Combined with Maven and its intranet, or just put on any intranet page, this could be a useful tool for developers.

(I just read the Terms of Service for Yahoo, and I didn’t see any prohibitions on commercial use of Yahoo Messenger; however, there are a couple of interesting clauses that anyone using it should be aware of. In section 3, I found out that Yahoo can terminate your account if your information is not kept up to date (not really enforceable, eh?). And in section 16, “[y]ou agree not to access the Service by any means other than through the interface that is provided by Yahoo! for use in accessing the Service.” I wonder if that prohibits Trillian?)

One issue I have with the Yahoo client is the way status works. Presence is not a binary concept (there/not there); rather, it is broken down into various statuses–(not there/available/busy/out to lunch…). What I find myself doing is being very conscientious about changing my status from available to unavailable. However, I rarely remember to change back, which degrades the usefulness of the presence information. (If you have to ping someone over IM to see if they’re actually there, it means you might as well not have status information at all.) I spent some time browsing the preferences of Yahoo’s client, as well as googling, but didn’t find any way to have the client pop up a message the first time I IM someone when my status is not available.

IM is very useful, and I can’t imagine working without it now. I don’t know what I’m going to do when Yahoo starts charging for it.

Technology | moore |

NextBus: a mobile poster child

I think that NextBus is a fantastic example of a mobile application. This website, which you can access via your mobile phone, tells you when the next bus, on a particular line, is coming. So, if you’re out and about and have had a bit much to drink, or if you’ve just forgotten your bus schedule, you can visit their site and find out when the next bus will be at your stop. It’s very useful.

This is almost a perfect application for a mobile phone. The information needed is very time sensitive and yet is easy to display on a mobile phone (no graphics or sophisticated data entry needed). NextBus has a great WAP interface, which probably displays well on almost every modern phone. The information is freely available (at least, information on when the next bus is supposed to arrive is freely available–and this is a good substitute for real time data).

And yet, there are profound flaws in this service. For one, it abandons a huge advantage by not knowing (or at least remembering) where I am. When I view the site to find out when the 203 is coming by next, I have to tell the site that I’m in Colorado, and then in Boulder. The website is a bit better, remembering that I am an RTD customer, but the website is a secondary feature for me–I’m much more interested in information delivered to my phone.

Also, as far as I can tell, the business model is lacking (and, no, I haven’t examined their balance sheets). I don’t know how NextBus is going to make money, other than extracting it from those wealthy organizations, the public transportation districts. (Yes, I’m trying to be sarcastic here.) They don’t require me to sign in or pay anything for the use of their information, and I see no advertising.

So, a service that is almost perfect for the mobile web because of the nature of the information it conveys (textual and time sensitive) is flawed because it’s not as useful as it could be and the business model is up in the air. I can’t imagine a better poster child for the mobile Internet.

Mobile Technology Technology | moore |

Syndication and blogs

I’ve tried to avoid self-referential blogging, if only becuase I’m not huge into navel staring. But, I just ran across an interesting blog: Wendyopolis, which is apparently associated with a Canadian magazine. Now, according to google, blogs are defined as:

“A blog is basically a journal that is available on the web. The activity of updating a blog is “blogging” and someone who keeps a blog is a “blogger.” Blogs are typically updated daily using software that allows people with little or no technical background to update and maintain the blog.

Postings on a blog are almost always arranged in chronological order with the most recent additions featured most prominently.”

(From the Glossary of Internet Terms)

However, I’d argue that there are several fundamental characteristics of a blog:

1. Date oriented format–“most recent additions featured most prominently.”
2. Informal, or less formal, writing style.
3. Personal voice–a reader can associate a blog with a person or persons.
4. Syndicatability–the author(s) provide RSS or Atom feeds. The feeds may be crippled in some way, but they are available.
5. Permalinks–postings are always available via an unchanging URL.

I can’t really think of any other salient characteristics. But the reason for this post is that Wendyopolis, which looks to be a very interesting weblog, doesn’t have #4. In some ways, that’s the most important feature, because it allows me to pull content of interest to one location, rather than visit sites.

I’ve written about this before, so I won’t beat a dead horse. Suffice it to say that, while Wendyopolis may speak to me right now, the chances of me ever visiting that blog ever again are nil, because of the lack of syndication. Sad, really.

Technology | moore |

Jetspeed 1 and 2

Here’s an article about Jetspeed 2. I’m actually very excited about this, though I feel that compliance to the spec is overrated. Perhaps I’m not really an enterprise developer, but I haven’t seen very many situations where I wanted a portlet (or an EJB) that had been developed on one portal server and deployed to another. But some of the Spring oriented features and ability to deploy struts application war files as portlets seem pretty neat and useful.

I’m currently working on a portal application, and we’re using Jetspeed 1–version 1.5, which has extensive documentation and has actually been released. JS1 is built on the Turbine framework. I hadn’t done much looking at this (other than a glance when I was looking at Torque for an OR layer). But so far, I’ve been really really impressed with Jetspeed and Turbine.

What has most impressed me is the configurability of these frameworks. There are a set of properties files that specify services, things like logging, persistence, localization, session validation, and authentication. The developers have done a great job of breaking these up into well defined chunks and letting me subclass services and plug in my own implementations. One example: our users do not login to the portal. Rather, they are authenticated by another application, which sets a cookie. I was able to disable Jetspeed’s own authentication system (which looks to a database) and plug in mine without making any modifications to source code. With properties overriding, I didn’t even have to modify the default properties files. Fantastic.

Jetspeed supports both JSP and Velocity as templating languages for the view. Velocity is used throughout the default portal, and I decided to use it as well. It’s an interesting language which has a lot of the benefits I’ve read about Groovy–there’s no types, and methods and properties look the same. It does look a bit perlish, I’ll admit–lots of $ and #, but it’s been fun to learn a different view language.

JS1 also provides an easy framework for developing portlets–an MVC framework, in fact. I don’t want to repeat what the relevant section of the portlet tutorial says, so I’ll just mention that developing dynamic content is a breeze.

I don’t want to say that Jetspeed has been a pure joy, however. There were a few days a couple of weeks ago that I wondered whether it had been a good choice at all. We have an existing base of users (hence the alternate authentication) and were noticing that the portal was loading slow when running against a user table of around 100K users. Then I ran some tests with The Grinder and noticed it was running really slow. Like 30 seconds to render a page with 5 portlets. Luckily, some sleuthing around indicated that there was much extraneous database access going on, and when that was eliminated, performance became acceptable.

In addition, the default build process is mavenized. I had an extremely bad experience and ended up writing a simple ant build script to do what I want. It’d be nice if both were options–since lots of people come to JS1 looking to slap a portal together for cheap, rather than thrash around with a complex build process. (I’d say at least forty percent of the messages to the mailing list are build related–not a good sign.) I just went to a BJUG talk about Maven, and Thompson was persuasive, so I might give maven another chance.

All in all, though, I’ve been very happy with Jetspeed. I am looking forward to JS2; I wish the timing had been better so I could have used it on the current project.

Java | moore |

Useful tools: p6spy

This entry kicks off a series of entries where I’ll examine some of my favorite tools for development. Some of them will be long, some short, but all of them will highlight software I use to make my life a bit easier.

A large, large chunk of the development I do is taking data from a relational database to a an HTML screen, and back again. Often there are business rules for transforming the data, or validation rules, but making sure the data is stored safely and consistently is a high priority, and that means a relational database.

However, I do much of my work in java, which means that the relational-OO impedance mismatch is a common problem. One common way to deal with it is to use an OR tool–something like OJB or JDO. These tools provide object models of your database tables, usually with some help from you. You then have the freedom to pretend like your database doesn’t exist, and use these objects in your application. The OR framework takes care of the dirty work like SQL updates and caching.

Every convenience has its price, however, and OR mapping tools are no exception. The same abstraction that lets you pretend that you’re simply dealing with objects means that you cannot easily examine the SQL that is generated. In addition, the way that you’re using the objects may cause performance issues, because you’re treating the data as objects, rather than rows.

It’s much the same issue as calling methods over the network via RMI or accesing files via NFS: the abstraction is great and means that programmers don’t have to think about the consequences of remote access. But the failure of the abstraction can be catastrophic, all the more so because the programmer was not expecting to have to deal with the grotty details under the abstraction (that’s the whole point, right?).

OR tools do not fail often, or have many catastrophic failure modes, but they sure can be slow. With open source software, you can dig around and see how SQL is being generated, but that’s tedious and time consuming. With commercial products, you don’t even have that option. (Some OR tools may have their own ‘Show me the SQL’ switch–I haven’t run into them.)

Enter p6spy. p6spy can be used in place of any JDBC driver. You point it to the the real driver and it passes on any configuration or SQL calls to that driver. But p6spy logs every SQL statement passed to it and every result set passed back. (A fine non object oriented example of the Decorator pattern.)

It took me about 15 minutes to figure out how to use p6spy, the software is open source with decent documentation, the latest version has data source support, and it scratches an itch that most, if not all, java developers will have at some time. With p6spy, you can find out what that OR tool is doing under the covers–it’s an easy way to peel back some of the abstraction if needed.

Java Programming Useful Tools | moore |

Koders.com–search source code

Koders.com has apparently indexed many open source software projects. (Link via Dion.) I played around with it a bit and I think it’s a very slick application. I’m of two minds about this, though.

The good:

Code reuse is good. A co-worker of mine once called it ‘editor inheritance’–in a world where people time is expensive and disk space is cheap, it can make sense (not always) to just copy code rather than figure out how to make a piece of code re-usable. Koders lets you do this in a more effective way.

It also lets coders easily compare and contrast styles between real live projects. And I can only imagine that soon some researcher will sink his teeth into all the code and publish on First Monday.

The bad:

As the linux-SCO lawsuits have shown, it’s technically awfully easy to cut and paste code, but the results end up being illegal. I can only see this repository, even though it differentiates by license, exacerbating this problem. And mixing and matching code from different licenses becomes all the easier as they show up side by side in a search engine. If I were a company concerned with legal ramifications, I’d tread softly around this tool.

The possibilities:

Regardless, I have to say it’s a very cool application. I’ll be interested to find out how much people will use it. What would be really cool is further analysis–after all google gets its power from the links between websites–what would we learn by examining the links between code? For one, you’d have a better idea how useful and stable a project is, if you could know how many other projects used it. Having a plugin into a UML modelling tool would be pretty slick too.

Programming | moore |

Testing Korean content

I’m currently working on a site that needs to be truly localized for a large number of languages (tens of them). This is accomplished with large numbers of ResourceBundles, the MessageFormat class when variable text layout is needed, an Oracle backend which understands and doesn’t muck with UTF-8, an Access database which generates said bundles, and a crack team of translators.

However, how to test? Luckily, it’s fairly easy to have IE use a different language: clear instructions live here. One issue with the instructions is that they don’t tell you how to actually install a language pack. But this is easy too: I only had to right click on a page, choose the encoding menu, then choose more, and then the encoding I wanted (Korean, because I want to test double byte characters). I was then prompted to install a language pack. I accepted, and Windows downloaded a bunch of DLLs and other files. From then on I could view Korean characters (the encoding menu says I’m viewing ‘Unicode (UTF-8)’). Here’s a random site about mining that you can use to test your Korean language pack.

Don’t forget to test both the input and output of your application–saving user input, and being able to redisplay it is at least as important as being able to display what you draw from your ResourceBundle initially. As a bonus, the Korean character set that I installed via IE was made available to Firefox. This was done on the fly, not only did I not need to restart Windows, I didn’t even need to restart Firefox; I just needed to reload the page.

Programming | moore |

Mobile phones as examples of computing in context

Here’s an interesting 20 page paper examining some of the issues surround context and computing.

A few choice quotes:
“…answering the telephone has something of a moral compulsion.”

“…as much of this problem [a phone that understands context] reduces to that of building an intelligent computer.”

“…it is better to have machines which act in predictable ways so users can understand how they work” rather than unpredictable machines that ‘do the right thing.’

“A technology, like mobile phones, with its combination of voice mail, text messaging and the like, is something we dwell with in that it becomes part of the fibre of our practices and lives, even for those without(sic) reject them.” As someone who swore off mobile phones for a long time and now doesn’t know how life continued without them, I can sympathize with that sentiment.

“When people use a technology over time, and get used to seeing other people
using the technology, the actions of the technology come to be seen not as actions of technology but of the user themselves.”

Interesting reading.

Via Mobile Community Design

Mobile Technology Technology and Society | moore |

Extending attributes of entities in relational databases

When you are data modeling, entities have attributes. During the early part of a project, it’s possible to map out many of these attributes, but often you miss some–the requirements change, the customer changes their mind, or the architects missed something at the beginning. Depending on how you’ve modeled those attributes, the pain of adding, modifying or removing them can be mellow or intense. In addition, often the values stored in these attributes need to be queried, or modified themselves.

Suppose you have a employee table (I’m trying to do this with SQL 92 syntax but I am not a DBA):
create table emp (emp_id numeric, first_name varchar(100), last_name varchar(100), dept varchar(50));
and you suddenly need to add middle name and salary to this table. There are three ways to create an extensible schema in a relational database. Each of these has their pluses and minuses.

1. The DDL method of extension
alter table emp add middle_name varchar(100), salary numeric;
Here, you simply add another column. For querying and clarity, this method is fantastic. These columns can be indexed and it’s clear that employees now have two additional attributes. However, this also means that any mapping you have between your model objects and your database needs to be updated; probably code needs to be regenerated to add these two attributes to your model objects. It also means that you have to version your database–since code that expects a middle_name attribute on employee will probably die a horrible death if that column is missing. In addition, depending on the size of the system, you might need to get a DBA involved.

2. The DML method of extension
create table emp_attributes (emp_id numeric references emp(emp_id), name varchar(100), value varchar(100));
insert into emp_attributes (1, "middle_name", "Sam");
insert into emp_attributes (1, "salary", "100000");
In this case, you can add attributes without getting a DBA involved–you simply add columns into this table. However, there is no referential integrity on the name of the attribute (is middle_name the same as mid_name the same as MIDDLE_NAME?–though, to be fair, you can put constrains on the values of the name column). In additional, the value column is not typed; though almost any data type can be stored as a string, you can lose precision and waste time converting from string to the actual type you want. In addition, querying based on these attributes is tedious:
select first_name from emp e, emp_attributes ea where e.emp_id = ea.emp_id and ea.name = "name" and ea.value ="Sam"
If you want to get all employees paid more than Sam, you need to resort to database specific functions to convert that string to a number.

3. The stored object method
alter table emp add objectdata varbinary;
With this method, you create a object or data structure in memory and serialize it to a stream of bytes which you then store in the objectdata column. This is great because you can add whatever attributes you like and the database structure doesn’t need to change at all. However, the data is unreadable by normal SQL tools and other programming languages. Querying on this data also becomes very difficult and slow, as you end up having to recreate each employees data object and test conditions in the programming language–you’re not taking advantage of the database.

There are a couple of questions that can help you determine which method you should use: How often will attributes be added? How hard is the process for that? How difficult is it to regenerate your data layer? Will you want to use SQL tools?

In general, the DDL method is the best option. It’s just the cleanest, easiest to understand and query against. The DML method is the second best, as you can still use most of the SQL toolset, even if it’s more complicated. The stored object method for extending attributes in a relational database should be used carefully, when there are a large number of attributes which can change often and will never be queried upon.

Databases Programming | moore |