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| <body> |
| <h1>Step 3 - Reading the Service Configuration</h1> |
| |
| <p> |
| Services typically have configuration. Configurations are directly supported in Zest™. A |
| <code>ConfigurationComposite</code> is a subtype of <code>EntityComposite</code>. That is because |
| configurations are stored in EntityStores, can be modified in runtime by client code and has |
| the same semantics as regular entities. |
| </p> |
| <p> |
| 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 <code>"properties"</code> in the same package as the service. |
| </p> |
| <p> |
| For this exercise, create a <code>LibraryConfiguration</code> 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. |
| </p> |
| |
| <p>Steps to do.</p> |
| <ol> |
| <li>Create a <code>LibraryConfiguration</code> interface that extends <code>ConfigurationComposite</code>, |
| and has three <code>Property</code> instances named <code>"titles"</code>, <code>"authors"</code> and |
| <code>"copies"</code>, where the first two are of <code>String</code> type and the last is of |
| <code>Integer</code> type. |
| </li> |
| <li>Delete the <code>LibraryActivator</code> and remove the <code>@Activators</code> annotation from the |
| <code>LibraryService</code> and the corresponding <code>createInitialData</code> method. |
| </li> |
| <li> |
| In the <code>LibraryMixin</code> remove the member injection of the <code>ValueBuilderFactory</code>, and |
| instead inject the <code>ValueBuilderFactory</code> in the constructor. |
| </li> |
| <li> |
| Inject the <code>LibraryConfiguration</code> via the constructor. The injection scope is <code>@This</code>. |
| </li> |
| <li> |
| Create a resource called <code>LibraryService.properties</code> and place it in the directory |
| <code>org/qi4j/tutorials/services/step4</code> in the classpath (for instance, <code>src/main/resources</code> |
| ). |
| Put something like; |
| <span class="javaxcode"><pre>titles=Domain Driven Design, Pragmatic Programmer, Extreme Programming Explained |
| authors=Eric Evans, Andy Hunt, Kent Beck |
| |
| #Number of copies of each book. |
| copies=3 |
| </pre> |
| </span> |
| in this file. |
| </li> |
| <li> |
| Load initial data from the <code>LibraryConfiguration</code> in the <code>LibraryMixin</code> constructor. |
| </li> |
| </ol> |
| </body> |
