wicket-modelfactory

Wicket-modelfactory is an API to create Wicket PropertyModels in a typesafe and refactoring-safe way.

Code says more than thousand words:

IModel<Integer> ageModel = model(from(myPersonObject).getAge());

IModel<String> streetModel = model(from(myPersonObject).getAdressData().getHomeAdress().getStreet());

where myPersonObject can be a typed IModel or a Bean.

You can also create Property Path-Strings in order to use them where PropertyModels are not helpful (PropertyColumns for instance).

String streetPropertyPath = path(from(myPersonObject).getAdressData().getHomeAdress().getStreet());

Usage

Maven

add the following section to your pom.xml:

  <dependency>
   <groupId>org.wicketeer</groupId>
   <artifactId>wicket-modelfactory</artifactId>
   <version>0.9.13</version> <!-- or the latest released one -->
  </dependency>

model(), path() and from() are static methods on ModelFactory. You should probably prepare your IDE to import these. Here is how this is done with Eclipse:

go to Preferences Dialog
Open Java / Editor / Content Assist / Favorites
add Type org.wicketeer.modelfactory.ModelFactory

Tip

If you use the excellent [lombok|http://project-lombok.org] project, you end up with very little boilerplate and type-safe models:

@Data class Bar{
 private Foo foo;
}
@Data class Foo{
 private String myString;
}
...
IModel<Integer> ageModel = model(from(barInstance).getFoo().getMyString());

Kudos

The idea is pretty old. There are several implementations around, this lib steals from:

SafeModel

Wicket Wiki using LambdaJ

and probably some more…

The reason for this little project is that we liked the SafeModel-API (using a ThreadModel) better than the lambdaJ approach.

tl;dr;

SafeModel = nice but slow

LambdaJ = fast but a little more clumsy and sometimes JIT breaks it.

Longer version of the story:

Safemodel exposes a nicer API that makes use of ThreadLocals in order to chain calls. On the other hand SafeModel happens to be too slow for us (We had a page with >600 models that went up from 150ms to 2700ms just by using SafeModel rather than lambdaJ.

LambdaJ on the other hand has a feature of JITting that, being enabled, caused spuriously intermixed models/failures.

Implementation

We faciliated LambdaJ (without the JITing), Objenesis, GentyRef & CGLib.

While this list of dependencies may sound frightening, the only dependency you need that does not necessarily come with Wicket is cglib:cglib-nodep:2.2.2. (Note: If you use wicket-ioc, you’ll have this dependency anyway.)

The rest of the dependencies are shaded into an internal package of Wicket-modelfactory, in order not to interfere with your dependecy management.

Unfortunately, this is not easy to do with CGLib, as it contains Strings referencing its classes.