Nesting objects within other objects (in YAML)

[micsport13]

First, if this is not the best place to put this kind of question, please let me know so I can put this somewhere else.
I have been trying to serialize this class using a custom serializer and I have been having some trouble being able to get it serialize correctly.
Here's the class I'm trying to serialize:

public class Schema {
  @JsonProperty("table_constraints")
  @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.EXTERNAL_PROPERTY)
  private final Map<Constraint, Set<Column<?>>> constraints;

  private final Set<Column<?>> columns;

And here is the custom serializer:

public class SchemaSerializer extends StdSerializer<Schema> {

  @Override
  public void serialize( 
      Schema schema, JsonGenerator jsonGenerator, SerializerProvider serializerProvider)
      throws IOException {
    log.info("Serializing schema: " + schema.toString());
    jsonGenerator.writeStartObject();
    jsonGenerator.writeArrayFieldStart("columns");
    for (var column : schema.getColumns()) {
      jsonGenerator.writeObject(column);
    }
    jsonGenerator.writeEndArray();
    jsonGenerator.writeArrayFieldStart("constraints");
    for (var constraint : schema.getConstraints().entrySet()) {
      jsonGenerator.writeStartObject();
      jsonGenerator.writeObject(constraint.getKey())  <--- This line is the problem
      jsonGenerator.writeArrayFieldStart("columns");
      for (Column<?> column : constraint.getValue()) {
        jsonGenerator.writeString(column.getName());
      }
      jsonGenerator.writeEndArray();
      jsonGenerator.writeEndObject();
    }
    jsonGenerator.writeEndArray();
    jsonGenerator.writeEndObject();
  }
}

Here's the desired output:

 columns:
   - name: intColumn
      type:
        name: integer
     - name: varcharColumn
        type:
          name: varchar
          max_length: 1
constraints:
  - type: primary_key
    columns:
      - intColumn
  - type: unique
    columns:
      - varcharColumn

The constraint object is handled through annotations so I wasn't sure how to get it to just serialize the name provided in the annotation. If I try jsonGenerator.writeObjectField("type", constraint.getKey()), it wraps it with another "type" key instead of just providing the value. Any idea how to write another object within the same JsonObject?

[cowtowncoder]

Going forward, please mention which format you are talking about: looking at output, I assume it is YAML.

But beyond that, this sounds like an excellent Question for Discussions; I hadn't enabled Discussions yet for this repo, just did. Will convert.