How to get value of a list of list of RichText or RichTextData

Question

One of the ContentModelData returns content in the below format.

Code 1

content =  {question=Question 1?, answer={paraContent=RichTextData(fragments=[No. Answer 1 <strong>Strong text here</strong> Answer continues <br /> Answer para 2.])}}

question has value of type String, and answer is a list of paragraphs containing heading, list of paraContent. List of paracontent is actually a list of RichText. Now sometimes paraContent is simply a list of RichText fields but when we create RichText Data, RichTextData fragments are created. I have tried many methods.

Code 2

1. paraMultiLevel= (List<ParagraphMultiLevel>)
    content.getAndCast("answer", ParagraphMultiLevel.class);

2. paraMultiLevel2 = (List<ParagraphMultiLevel>)content.getElement("answer");

3. (List<ParagraphMultiLevel>)content.get("answer")

None of the above populates my entity viewModel. I am getting an exception

com.sdl.dxa.api.datamodel.model.ContentModelData cannot be cast to java.util.List

How can I fetch the Answer value and set it on a List <List<ParagraphMultiLevel> so I can access it in my view?

Update on 04/04/2018

When I originally tried to convertEntites(List<ComponentMetadata>) (see code 3), it returned null values so then I had to manually iterate over the list of ids and got the EntityModelData using DefaultModelService.loadEntity(). From the EntityModelData I get the ContentModelData (see Code 1). I want to set my customTeaser.content with ContentModelData.get("answer").

Code 3

try { dynamicList.setQueryResults(customContentProvider._convertEntities(components, dynamicList.getEntityType(), localization), query.isHasMore());
} catch (DxaException e) {
    throw new ContentProviderException("Cannot populate a dynamic list " + dynamicList.getId() + " localization " + localization.getId(), e);
}

returned [ContentTeaser(headline=null, introduction=null, content=null,...

Code 4

 @SemanticEntities({
     @SemanticEntity(entityName = "FAQs", vocabulary = SDL_CORE, prefix = "f")
 })

 public class ContentTeaser extends AbstractEntityModel {
     @JsonProperty("Headline")
     private String headline;

     @SemanticProperty("f:question")
     @JsonProperty("Introduction")
     private String introduction;

     @SemanticProperty("f:answer")
     @JsonProperty("Content")
     private List<ParagraphMultiLevel> content;             
 }

Code 5

@SemanticEntity(entityName = "ParagraphMultiLevel", vocabulary = SDL_CORE, prefix = "pml")
@Data
@EqualsAndHashCode(callSuper = true)
public class ParagraphMultiLevel extends AbstractEntityModel {      
    @SemanticProperty("pml:heading")
    @JsonProperty("Heading")
    private String heading;

    @SemanticProperty("pml:paraContent")
    @JsonProperty("ParaContent")
    private List<RichText> paraContent;

    @SemanticProperty("pml:subParagraph")
    @JsonProperty("SubParagraph")
    private List<SubParagraphLevel2> subParagraph;

    @SemanticProperty("pml:paraFootnote")
    @JsonProperty("ParaFootnote")
    private List<RichText> paraFootnote;
}

Answer 1

It seems you are trying to mix the R2 Data Model (e.g. ContentModelData) with your Strongly Typed View Models (e.g. ParagraphMultiLevel). That doesn’t work.

The DXA Semantic Mapping logic is used to map the data in the R2 Data Model to Strongly Typed View Models, but these are distinct models; you won’t be able to simply cast one to the other.

See, for example: https://github.com/sdl/dxa-web-application-java/blob/master/dxa-framework/dxa-tridion-provider/src/main/java/com/sdl/dxa/tridion/mapping/EntityModelBuilder.java