Using the EMF compile-time reflection API I created a generic EMF ECore Feature Model implementation that leverages the compile-time references to structural features. Most of the code is actually related to working around the fact that EAttributes and EReferences are not serializable but which they should to be part safely referenced in a model that potentially is serialized by Wicket between requests.<\/p>\n

import org.apache.wicket.model.IDetachable;\r\nimport org.apache.wicket.model.IObjectClassAwareModel;\r\nimport org.eclipse.emf.ecore.EClass;\r\nimport org.eclipse.emf.ecore.EClassifier;\r\nimport org.eclipse.emf.ecore.EObject;\r\nimport org.eclipse.emf.ecore.EPackage;\r\nimport org.eclipse.emf.ecore.EStructuralFeature;\r\n\r\n\/**\r\n * A property model to bind an attribute of an EMF ECore object\r\n * \r\n * @author Sebastian Thomschke\r\n *\/\r\n@SuppressWarnings(\"unchecked\")\r\npublic class EFeatureModel<T> implements IObjectClassAwareModel<T>\r\n{\r\n\tprivate static final long serialVersionUID = 1L;\r\n\r\n\tprivate transient EStructuralFeature feat;\r\n\tprivate String featContainerClassName;\r\n\tprivate String featName;\r\n\tprivate String featPackageNsURI;\r\n\r\n\tprivate EObject target;\r\n\r\n\tpublic EFeatureModel(EObject target, EStructuralFeature efeature)\r\n\t{\r\n\t\tthis.target = target;\r\n\t\tthis.feat = efeature;\r\n\t\tthis.featName = efeature.getName();\r\n\t\tthis.featContainerClassName = efeature.getContainerClass().getName();\r\n\t\tthis.featPackageNsURI = ((EPackage) efeature.eContainer().eContainer()).getNsURI();\r\n\t}\r\n\r\n\tpublic void detach()\r\n\t{\r\n\t\tif (target instanceof IDetachable) ((IDetachable) target).detach();\r\n\t}\r\n\r\n\tpublic EStructuralFeature getFeature()\r\n\t{\r\n\t\tif (feat == null)\r\n\t\t{\r\n\t\t\tEPackage ePackage = EPackage.Registry.INSTANCE.getEPackage(featPackageNsURI);\r\n\t\t\tfor (Object eClassifierItem : ePackage.getEClassifiers())\r\n\t\t\t{\r\n\t\t\t\tEClassifier eClassifier = (EClassifier) eClassifierItem;\r\n\t\t\t\tif (eClassifier.getInstanceClass().getName().equals(featContainerClassName))\r\n\t\t\t\t\tfeat = ((EClass) eClassifier).getEStructuralFeature(featName);\r\n\t\t\t}\r\n\t\t}\r\n\t\treturn feat;\r\n\t}\r\n\r\n\tpublic T getObject()\r\n\t{\r\n\t\treturn (T) target.eGet(getFeature());\r\n\t}\r\n\r\n\tpublic Class<T> getObjectClass()\r\n\t{\r\n\t\treturn getFeature().getEType().getInstanceClass();\r\n\t}\r\n\r\n\tpublic void setObject(T object)\r\n\t{\r\n\t\t\/\/ do nothing if the object is the same instance that is returned by the getter\r\n\t\t\/\/ this is esp. important for collection properties\r\n\t\tif (target.eGet(getFeature()) == object) return;\r\n\r\n\t\ttarget.eSet(getFeature(), object);\r\n\t}\r\n\r\n\t@Override\r\n\tpublic String toString()\r\n\t{\r\n\t\treturn new StringBuilder(\"Model:classname=[\").append(getClass().getName()).append(\"]\").append(\":target=[\")\r\n\t\t\t\t.append(target).append(\"]\").toString();\r\n\t}\r\n}<\/pre>\n
Using this new model implementation is as simple as using the PropertyModel provided by Wicket:<\/p>\n
IModel model = new EFeatureModel(myTicket, com.acme.service.ServicePackage.Literals.TICKET__COMMENT);\r\n<\/pre>\n
You can now fully enjoy the compile-time safeness of your EMF model.<\/p>\n
Making EObjects serializable<\/h3>\n
Wicket usually serializes components and their associated models between HTTP requests. If you are using the provided EPropertyModel your EObject classes must implement the Serializable interface. To achieve this, simply extend the EObject interface with the Serializables interface and set “Root Extends Interface” property in your genmodel configuration to this interface.<\/p>\n
\r\n\/**\r\n * @author Sebastian Thomschke\r\n *\/\r\npublic interface SerializableEObject extends EObject, Serializable {\r\n}\r\n<\/pre>\n
When you now regenerate the model classes they will extend the SerializableEObject interface and Wicket will stop complaining about objects in the model being not serializable.<\/p>\n","protected":false},"excerpt":{"rendered":"
Apache Wicket uses so called model objects to bind data objects to Wicket components. The framework provides a number of model implementations to access data objects and their properties in various ways. The PropertyModel implementation for example is used to access and set the value of a Java object using reflection. EPropertyModel If you are…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[43],"tags":[91,89,88,30,90,87],"class_list":["post-146","post","type-post","status-publish","format-standard","hentry","category-java-coding","tag-eclipse","tag-ecore","tag-emf","tag-java","tag-reflection","tag-wicket"],"_links":{"self":[{"href":"https:\/\/sebthom.de\/de\/wp-json\/wp\/v2\/posts\/146","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sebthom.de\/de\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sebthom.de\/de\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sebthom.de\/de\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/sebthom.de\/de\/wp-json\/wp\/v2\/comments?post=146"}],"version-history":[{"count":0,"href":"https:\/\/sebthom.de\/de\/wp-json\/wp\/v2\/posts\/146\/revisions"}],"wp:attachment":[{"href":"https:\/\/sebthom.de\/de\/wp-json\/wp\/v2\/media?parent=146"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sebthom.de\/de\/wp-json\/wp\/v2\/categories?post=146"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sebthom.de\/de\/wp-json\/wp\/v2\/tags?post=146"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}