CODEWITHSUNDEEP
eclipse-emfemfeclipse-emf-ecore
Łøćçâz Ł'âvîëstà
Łøćçâz Ł'âvîëstà

Reputation: 21

EMF error : the attribute "XYZ.Attribute_name" is not transient o it must have a data type that is serializable

I am creating an ECore model. I created an EClass and inside it I want to create a data member that is a list. So I created an EAttribute of type EEList.

However when I try to create the genmodel file I get an error saying

the attribute "XYZ.Attribute_name" is not transient o it must have a data type that is serializable.

It also gives a warning saying

The generic type associated with the 'EEList' classifier should have 1 type atrgument(s) to match the number of type parameter(s) of the classifier.

Can anyone tell me what I'm doing wrong? I could not figure out how to set the E in EEList<E>.

Upvotes: 1

Views: 449

Answers (1)

Lii
Lii

Reputation: 12122

First error

The first error probably disappears after you've fix the second error. I write an explanation here, but you probably don't have to deal with it to solve you problem.

It is because, to be saved to disk, the EDataTypes of attributes must be convertible to a text format.

There are two ways to ensure this:

  1. Implement conversion to and from strings for the used EDataType. Standard EMF EDataTypes already do this, but if you have created your own EDataType you have to do it manually.
  2. Use a Java type for the EDataType that is serializable. It must thus implement the Serializable interface and provide serializating operations. Many standard Java classes, such as String and Integer already do that.

Another solution is to set the Transient property of the attribute to true. The the attribute will not be saved and its EDataType does not need to be serialized.

Second error

The normal way to create a list attribute is to set the Upper Bound property of the attribute to a value different from 1. To create a list attribute which can contain any number of elements, set Upper Bound to -1, which means Unbounded.

The EAttribute Type should be set to the element type, not to a list type.

The generated Java code will contain a property with the type EList<ElementType>.

Upvotes: 1

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