Update the plugin.xml with an Xml parser when adding modelTypes & lan…

…guages descriptions.

We used the Eclipse api to edit the plugin.xml but it seems buggy/mis-used.
The model created doesn't contains extension tags present in the plugin.xml.
As a work around an XML parser do the job instead of the Eclipse API.

plugins/fr.inria.diverse.melange/src/main/java/fr/inria/diverse/melange/processors/ExtensionPointProcessor.xtend

@@ -19,6 +19,7 @@ import org.eclipse.xtext.documentation.IEObjectDocumentationProvider
 import org.eclipse.xtext.naming.IQualifiedNameProvider
 import com.google.common.collect.ListMultimap
 import com.google.common.collect.ArrayListMultimap
+import fr.inria.diverse.melange.utils.PluginXmlChanger
 
 /**
  * For each model type, create a new fr.inria.diverse.melange.modeltype
@@ -49,6 +50,10 @@ class ExtensionPointProcessor extends DispatchMelangeProcessor
 
 		if (project !== null && !preLinkingPhase) {
 			val pluginXml = PDEProject::getPluginXml(project)
+
+			val changer = new PluginXmlChanger
+			changer.load(pluginXml.location.toString)
+
 			val pluginModel = PDECore::getDefault.modelManager.findModel(project)
 			val fModel = new WorkspacePluginModel(pluginXml, false)
 			val pluginBase = fModel.pluginBase
@@ -70,93 +75,77 @@ class ExtensionPointProcessor extends DispatchMelangeProcessor
 				val languages = root.languages.filter[isComplete]
 
 				if (modelTypes.size > 0 && modeltypeExtensionPoint !== null) {
-					val newExtension = fModel.factory.createExtension => [
-						point = modeltypeExtensionPoint.id
-					]
+
+					changer.deleteExtensions(MODELTYPE_EXTENSION_POINT)
+					val extensionTag = changer.addExtension(MODELTYPE_EXTENSION_POINT)
 
 					modelTypes.forEach[mt |
 						try {
 							val fqn = mt.fullyQualifiedName.toString
 							val doc = documentationProvider.getDocumentation(mt)
-							val modeltypeElement = fModel.factory.createElement(newExtension) => [
-								name = "modeltype"
-								setAttribute("id", fqn)
-								setAttribute("uri", mt.uri)
-
-								if (doc !== null && !doc.empty)
-									setAttribute("description", doc)
-							]
-
+
+							val modelTypeTag = changer.addChild(extensionTag,"modeltype")
+							changer.addAttribute(modelTypeTag, "id", fqn)
+							changer.addAttribute(modelTypeTag, "uri", mt.uri)
+							if (doc !== null && !doc.empty){
+								changer.addAttribute(modelTypeTag, "description", doc)
+							}
+
 							// Register subtypings
 							mt.subtypingRelations.forEach[superMt |
-								modeltypeElement.add(fModel.factory.createElement(modeltypeElement) => [
-									name = "subtyping"
-									setAttribute("modeltypeId", superMt.superType.fullyQualifiedName.toString)									
-								])
+								val subtypingTag = changer.addChild(modelTypeTag,"subtyping")
+								changer.addAttribute(subtypingTag, "modeltypeId", superMt.superType.fullyQualifiedName.toString)
 							]
-
-							newExtension.add(modeltypeElement)
-							if (!newExtension.isInTheModel) {
-								fModel.extensions.add(newExtension)
-								log.debug('''Registered new modeltype contribution <«fqn», «mt.uri»> in plugin.xml''')
-							}
+
+							log.debug('''Registered new modeltype contribution <«fqn», «mt.uri»> in plugin.xml''')
 						} catch (CoreException e) {
 							log.debug('''Failed to register new model type contribution''', e)
 						}
 					]
 				}
 
 				if (languages.size > 0 && languageExtensionPoint !== null) {
-					val newExtension = fModel.factory.createExtension => [
-						point = languageExtensionPoint.id
-					]
+
+					changer.deleteExtensions(LANGUAGE_EXTENSION_POINT)
+					val extensionTag = changer.addExtension(LANGUAGE_EXTENSION_POINT)
 
 					languages.forEach[l |
 						try {
 							val fqn = l.fullyQualifiedName.toString
 							val doc = documentationProvider.getDocumentation(l)
-							val languageElement = fModel.factory.createElement(newExtension) => [
-								name = "language"
-								setAttribute("id", fqn)
-								setAttribute("exactType", l.exactType.fullyQualifiedName.toString)
-								setAttribute("uri", l.syntax.pkgs.head.nsURI)
-
-								if (doc !== null && !doc.empty)
-									setAttribute("description", doc)	
-
-								setAttribute("entryPoints",
+
+							val languageTag = changer.addChild(extensionTag,"language")
+							changer.addAttribute(languageTag, "id", fqn)
+							changer.addAttribute(languageTag, "exactType", l.exactType.fullyQualifiedName.toString)
+							changer.addAttribute(languageTag, "uri", l.syntax.pkgs.head.nsURI)
+							if (doc !== null && !doc.empty){
+								changer.addAttribute(languageTag, "description", doc)
+							}
+							changer.addAttribute(languageTag, "entryPoints", 
 									l.entryPoints
-									 .map[
-									 	val args = parameters.map[it.parameterType.type.qualifiedName].join(',')
-									 	declaringType.qualifiedName+"."+simpleName+"("+args+")"
-									 ]
-									 .join(';')
+									.map[
+										val args = parameters.map[it.parameterType.type.qualifiedName].join(',')
+										declaringType.qualifiedName+"."+simpleName+"("+args+")"
+									]
+									.join(';')
 								)
-								setAttribute("aspects", l.serializedAspects)
-							]
-
+							changer.addAttribute(languageTag, "aspects", l.serializedAspects)
+
 							// Register adapters
 							l.implements.forEach[mt |
-								languageElement.add(fModel.factory.createElement(languageElement) => [
-									name = "adapter"
-									setAttribute("modeltypeId", mt.fullyQualifiedName.toString)
-									setAttribute("class", l.syntax.adapterNameFor(mt))
-								])
+								val adapterTag = changer.addChild(languageTag,"adapter")
+								changer.addAttribute(adapterTag, "modeltypeId", mt.fullyQualifiedName.toString)
+								changer.addAttribute(adapterTag, "class", l.syntax.adapterNameFor(mt))
 							]
-
-							newExtension.add(languageElement)
-							if (!newExtension.isInTheModel) {
-								fModel.extensions.add(newExtension)
-								log.debug('''Registered new language contribution <«fqn»> in plugin.xml''')
-							}
+							log.debug('''Registered new language contribution <«fqn»> in plugin.xml''')
 						} catch (CoreException e) {
 							log.debug('''Failed to register language contribution''', e)
 						}
 					]
 				}
 			}
 
-			fModel.save
+			changer.save(2)
 		}
 	}