Support for ArrayNodes in Entity Properties

[AndreasMeier12]

I am using version 2.0.1.

Context

I am working on interoperability between systems (mostly repositories and electronic lab notebooks). To this end, we want to include a schema describing the metadata in our RO-Crates.
Certain properties can have arrays as values, e.g. https://schema.org/domainIncludes. I would like to use them in my schema.

The problem

There is a way to pass ArrayNode as an argument to build an entity: edu.kit.datamanager.ro_crate.entities.AbstractEntity.AbstractEntityBuilder#addProperty(java.lang.String, com.fasterxml.jackson.databind.JsonNode)
Internally, this does not pass validation and the values are not written in the ro-crate-metadata.json.

In the documentation, I only see arrays for specific entities, e.g. edu.kit.datamanager.ro_crate.entities.data.WorkflowEntity.AbstractWorkflowEntityBuilder#addOutput.

Is there a way to add these values to my property for DataEntity in the form of an array?

Edit:
After trying some more things, I received the following output:

The property: 
[ {
  "@id" : "xsd:string"
} ]
does not comply with the flattened structure of the RO-Crate json document.

I see arrays inside data entities in RO-Crate's examples, e.g. encodingFormat taken from https://www.researchobject.org/ro-crate/specification/1.1/data-entities.html

{
    "@id": "1st-tool.cwl",
    "@type": "File",
    "name": "First executable tool",
    "description": "An example Common Workflow Language File",
    "contentSize": "120",
    "encodingFormat": ["text/plain", {"@id": "https://www.commonwl.org/v1.0/Workflow.html"}]
  }

Did I interpret the example correctly?

Suggestion

If this is not yet supported, would it be possible to add arrays as values?

[AndreasMeier12]

I've got something. The problem was that I used my own class for IDs. The correct way of doing it is:

new DataEntity.DataEntityBuilder()
                        .addIdProperty("domainIncludes", "xsd:string")
                        .addIdProperty("domainIncludes", "xsd:boolean")

This produces my desired array:

    "domainIncludes" : [ {
      "@id" : "xsd:string"
    }, {
      "@id" : "xsd:boolean"
    } ]

[Pfeil]

Sorry for the late response. Your solution is correct: The idea is that arrays will be created if an "add*" method is called multiple times. Methods called "set*" will instead override a previous value, if called twice. If you find any inconsistency in this regard, I'd call it a bug and ask you to open an issue :)

The example you mentioned is not given as a full crate and therefore not yet included as a test, I believe. I will open an issue in order to do so and see if we can fully reproduce this using the current API. Also, I think I should document/highlight the purpose of add* and set* more clearly. I'll make an extra issue for that. Thanks!