# Step 3 - Reading the Service Configuration

Services typically have configuration. Configurations are directly supported in Zest™. A `ConfigurationComposite` is a subtype of `EntityComposite`. That is because configurations are stored in EntityStores, can be modified in runtime by client code and has the same semantics as regular entities.

Zest™ also handles the bootstrapping of configuration for the services. If the ConfigurationComposite is not found in the configured entity store, then Zest™ will automatically locate a properties file for each service instance, read those properties into a ConfigurationComposite instance, save that to the entity store and provide the values to the service. The properties file must be with the same name as the service instance with the extension `"properties"` in the same package as the service.

For this exercise, create a `LibraryConfiguration` that contains "titles", "authors" and "copies". The first two are a string with a comma separated list, and the "copies" is just an Integer with how many copies are made of each title.

Steps to do.

1. Create a `LibraryConfiguration` interface that extends `ConfigurationComposite`, and has three `Property` instances named `"titles"`, `"authors"` and `"copies"`, where the first two are of `String` type and the last is of `Integer` type.
2. Delete the `LibraryActivator` and remove the `@Activators` annotation from the `LibraryService` and the corresponding `createInitialData` method.
3. In the `LibraryMixin` remove the member injection of the `ValueBuilderFactory`, and instead inject the `ValueBuilderFactory` in the constructor.
4. Inject the `LibraryConfiguration` via the constructor. The injection scope is `@This`.
5. Create a resource called `LibraryService.properties` and place it in the directory `org/qi4j/tutorials/services/step4` in the classpath (for instance, `src/main/resources` ). Put something like;

       titles=Domain Driven Design, Pragmatic Programmer, Extreme Programming Explained
       authors=Eric Evans, Andy Hunt, Kent Beck

       #Number of copies of each book.
       copies=3

   in this file.
6. Load initial data from the `LibraryConfiguration` in the `LibraryMixin` constructor.