WO Wideos

Seems like video is the new black in the WO community this week with the Ajax.framework from Project Wonder taking front billing.

Mike Schrag has posted a short video showing how to create and Ajaxify a new WebObjects app demonstrating some of the new features coming to WOLips.

John Larson has posted a YouTube video of some of the stuff he’s done leveraging the Ajax.framework.

Just a few of my favorite things…

Project Wonder is chocked so full of WebObjects goodness that it is hard to envision developing a project without it. Here are three bits that I use all the time.

Autolocking EditingContexts

Step one: Learn WebObjects

Step two: Realize that using the session().defaultEditingContext() exclusively is bad.

Step three: Start using multiple EOEditingContexts.

Step four: Read, re-read, then read again the documentation on EC locking.

Step five: Encounter production deadlocks.

Step six: Cry.

Thankfully Project Wonder provides an amazing solution in the form of autolocking EditingContexts. Enabling them is simple. Set some properties for your project:


There is an email from Mike Schrag with some juicy details here.

Change your code so that you never call new EOEditingContext(); instead use the ERXEC.newEditingContext() factory method.


Problem: You need access to an object in your session from an EO. Maybe you want to set a “createdBy” value to the current user in awakeFromInsertion

Adding a reference to the Session in your EOs would be bad so what are you going to do?

Solution: Use ERXThreadStorage to store a reference to the current user and access that from your EO.

In your Session.java:

public User currentUser; // assume exists

public void awake() {
    ERXThreadStorage.takeValueForKey(currentUser, "currentUser");

In your EO.java:

public void awakeFromInsertion(EOEditingContext ec) {
    User user = ERXThreadStorage.valueForKey("currentUser"));
    if (user != null) {


ERXGenericRecord is another Project Wonder class that is full of yumminess. Please read the API docs for the full details, but here are a few of my favorites:

willUpdate(); // called after saveChanges() but before validation
              // so it is safe to make changes. See the rest of
              // will* and did* methods for more

primaryKey(); // returns the primary key (null if the EO hasn't
              // been saved yet)

primaryKeyInTransaction(); // returns the primary key as above,
              // but if the EO hasn't beens saved yet, it'll
              // figure out what the pk should be, return it,
              // cache it, and use it later when the EO does get
              // saved. Very cool.

There is much, much more: ERXLocalizer, ERJavaMail, ERExcelLook… Dive into the docs and I’m sure you’ll find something usefull.

Connection Dictionary Twiddling

Another “so I don’t have to look it up” post:

Connection dictionaries are the collection of information in your eomodel that configures your access through jdbc to your database.

It is possible to set/modify this information through code and I, along with many others, have built classes that read these settings from your Properties file on app launch. Project Wonder has ERXConfigurationManager that will do this for you as well.


  • dbConnectURLGLOBAL=jdbc:mysql://host/dbname
  • dbConnectUserGLOBAL=dbuser
  • dbConnectPasswordGLOBAL=dbpassword

Just drop those entries into your Properties file and away you go. Also, because the ERXConfigurationManager reads all your Properties files, you can override the settings in your project with personal ones in your ~/WebObjects.properties resulting in fewer changes to make when deploying. In fact that little trick works great for er.javamail and log4j settings as well.