| [henshin-dev] Optional EJavaClass Attribute in HenshinTGG |
Dear Henshin(TGG) developers, I have a problem in HenshinTGG with an optional (i.e. a cardinality of 0..1) attribute of the type EJavaClass<T>. The core question is: How do I match an empty attribute in HenshinTGG? I.e. the value that is entered when I use the „Restore Default Value“ button in the properties view on an attribute in a „Sample Reflective Ecore Editor“. Please let me explain my situation. I have a meta model for my source model: Classes: DataType, Operation References: ownedOperations: DataType -> Operation, appReturnType: Operation -> DataType Attributes: javaReturnType: Operation I expect Operations to *either* have an appReturnType, or a javaReturnType. Having both is semantically forbidden. So I make 2 Transformations. The first one is FW_Operation2SomethingElse: from :DataType ++-ownedOperations-> ++[1]:Operation(attr: javaReturnType=jrt) to something else With a NAC No_AppReturnType: [1]:Operation -appReturnType-> :DataModel The second one is FW_Operation2SomethingElse_With_AppReturnType: from :DataType ++-ownedOperations-> ++:Operation(attr: *no attributes*) -appReturnType-> :DataType to something else When I execute the FW-Rules on my model I have the following problem. javaReturnType may be: correct, incorrect, non-existent appReturnType may be: set, non-existent 1. If I have an operation with a correct javaReturnType (e.g. „int“) an no appReturnType it is correctly translated. 2. If I have an operation with a correct javaReturnType and an appReturnType (which is semantically not correct), it is (syntactically) correctly translated. 3. If I have an operation with an invalid javaReturnType (e.g. „null“ or „thisShouldReallyBeEmpty“) (this is also semantically not correct), I get an exception, because the engine tries to set the value in a EJavaClass attribtue in the target model and cannot (ecore does not allow to set such values): org.eclipse.emf.common.util.WrappedException: java.lang.ClassNotFoundException: null cannot be found by org.eclipse.emf.ecore_2.9.1.v20130827-0309 at org.eclipse.emf.ecore.impl.EcoreFactoryImpl.createEJavaClassFromString(Ecor eFactoryImpl.java:906) at org.eclipse.emf.ecore.impl.EcoreFactoryImpl.createFromString(EcoreFactoryIm pl.java:146) at org.eclipse.emf.ecore.util.EcoreUtil.createFromString(EcoreUtil.java:3352) at de.tub.tfs.henshin.tggeditor.util.TggHenshinEGraph.henshin2emfGraph(TggHens hinEGraph.java:107) […] 4. If I have an operation with no javaReturnType I get an exception, which I usually get when a rule checks for an attribute that is not set (graphNode is null in line 298): java.lang.NullPointerException at de.tub.tfs.henshin.tggeditor.util.RuleUtil.checkAttributeMarker(RuleUtil.ja va:298) at de.tub.tfs.henshin.tggeditor.commands.OpRuleAttributeConstraint.check(OpRul eAttributeConstraint.java:66) […] I just made a table up for these cases as an overview: javaReturnType appReturnType Result correct non-existent correct transformation correct set correct transformation but semantically forbidden incorrect * incorrect transformation: javaReturnType is not set on the other side due to exception non-existent * incorrect transformation: exception due to non-existent attribute All in all I find no possibility to do a correct transformation for the case that I have an appReturnType in my operation. The problem here is, that I seem to cannot set any empty javaReturnType. Thanks for your patience and best regards Marco -- Marco Konersmann, né Müller Research Associate paluno - The Ruhr Institute for Software Technology University of Duisburg-Essen * Gerlingstraße 16 * 45127 Essen * Germany * callto:+49-201-183-4682 * fax:+49-201-183-4698 http://www.paluno.eu * VAT-Nr. DE811272995 PGP/GPG key: http://www.s3.uni-duisburg-essen.de/pub/keys/0x7AE238AC.asc X.509 cert: https://pki.pca.dfn.de/uni-duisburg-essen-ca/cgi-bin/pub/pki?cmd=viewCert&k ey=5639645262406037
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