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| <h1 xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0">Code generation</h1> |
| <div class="section" title="Code generation"> |
| <div class="titlepage"> |
| <div> |
| <div> |
| <h2 class="title" style="clear: both"> |
| <a name="uml2example_codegen"/>Code generation</h2> |
| </div> |
| </div> |
| </div> |
| <div class="section" title="Defining the templates"> |
| <div class="titlepage"> |
| <div> |
| <div> |
| <h3 class="title"> |
| <a name="uml2example_codegen_templates"/>Defining the templates</h3> |
| </div> |
| </div> |
| </div> |
| <p>Inside the source folder of our project, create a |
| <code class="filename">templates</code> package. Inside that package folder, |
| create a template file <code class="filename">Root.xpt</code> that has the |
| following content. First, we define the entry template that is called |
| <code class="classname">Root</code>. Since we expect a UML model element to be |
| the top element to the model, we define it for |
| <code class="classname">uml::Model</code>. Note the use of the |
| <code class="classname">uml</code> Namespace prefix, as defined in the UML2 |
| metamodel. Inside that template, we iterate over all owned elements of |
| type <code class="classname">uml::Package</code> in the model and expand a |
| template for the packages defined in it.</p> |
| <pre class="programlisting">«DEFINE Root FOR uml::Model» |
| «EXPAND PackageRoot FOREACH allOwnedElements().typeSelect(uml::Package)» |
| «ENDDEFINE» |
| </pre> |
| <p>In the package template, we again iterate over all owned elements |
| and call a template that handles classes. Although we only have classes |
| in that package we could not rely on this in general. The package may |
| contain any other packageable element, so we need to filter classes |
| using <code class="methodname">typeSelect()</code>.</p> |
| <pre class="programlisting">«DEFINE PackageRoot FOR uml::Package» |
| «EXPAND ClassRoot FOREACH ownedType.typeSelect(uml::Class)» |
| «ENDDEFINE» |
| </pre> |
| <p>This template handles classes. It opens a file that has the same |
| name as the class, suffixed by <code class="filename">.java</code>. Into that |
| file, we generate an empty class body.</p> |
| <pre class="programlisting">«DEFINE ClassRoot FOR uml::Class» |
| «FILE name+".java"» |
| public class «name» {} |
| «ENDFILE» |
| «ENDDEFINE»</pre> |
| </div> |
| <div class="section" title="Defining the workflow"> |
| <div class="titlepage"> |
| <div> |
| <div> |
| <h3 class="title"> |
| <a name="uml2example_codegen_workflow"/>Defining the workflow</h3> |
| </div> |
| </div> |
| </div> |
| <p>In order to generate code, we need a workflow definition. Here is |
| the workflow file; you should put it into the source folder. The file |
| should be generally understandable if you read the Getting Started |
| chapter.</p> |
| <pre class="programlisting"><?xml version="1.0" encoding="ISO-8859-1"?> |
| <workflow> |
| </pre> |
| <p>You need to setup the UML2 stuff (registering URI maps, Factories, |
| etc.). This can be done declaring a bean in before of the |
| <code class="classname">XmiReader</code> |
| <a name="N12F92" class="indexterm"/> component:</p> |
| <pre class="programlisting"><bean class="org.eclipse.emf.mwe.utils.StandaloneSetup" > |
| <platformUri value=".."/> |
| </bean> |
| |
| <!-- load model and store it in slot 'model' --> |
| <component class="org.eclipse.emf.mwe.utils.Reader"> |
| <uri value="platform:/resource/xpand.uml2.generator/src/example.uml" /> |
| <modelSlot value="model" /> |
| </component></pre> |
| <p>The <code class="classname">XmiReader</code> reads the model and stores |
| the content (a list containing the model element) in a slot named |
| '<code class="varname">model</code>'. As usual, you might want to clean the target |
| directory<a name="N12FA1" class="indexterm"/>.</p> |
| <pre class="programlisting"><component id="dirCleaner" |
| class="org.eclipse.emf.mwe.utils.DirectoryCleaner" |
| directory="src-gen"/></pre> |
| <p>and in the generator we also configure the UML2 |
| metamodel<a name="N12FAA" class="indexterm"/>.</p> |
| <pre class="programlisting"> <component id="generator" class="org.eclipse.xpand2.Generator" skipOnErrors="true"> |
| <metaModel class="org.eclipse.xtend.typesystem.uml2.UML2MetaModel"/> |
| <expand value="templates::Root::Root FOR model"/> |
| <fileEncoding value="ISO-8859-1"/> |
| <outlet path="src-gen"> |
| <postprocessor class="org.eclipse.xpand2.output.JavaBeautifier"/> |
| </outlet> |
| </component> |
| </workflow></pre> |
| <p>If you run the workflow (by right clicking on the |
| <code class="filename">.mwe</code> file and select <span class="guiicon">Run As</span> → <span class="guimenuitem">MWE workflow</span>) the two Java classes should be generated.</p> |
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