Avro 架构对象 - 递归

Question

Is this possible to make class in avro schema that have one of his parameter as themself?

Example in java:

public class Example {

private Integer value;
private Example example;

}

Answer 1

Avro schema is not defined in java, but in a json file usually with .avsc file extension. Here's an example of a recursive avro schema that represents a tree:

{
  "type": "record",
  "name": "Node",
  "fields": [
    {
      "name": "value",
      "type": "long"
    },
    {
      "name": "children",
      "type": { "type": "array", "items": "Node" }
    }
  ]
}

So yes, it is perfectly possible to create recursive schemas.

See also this issue , where even a shorter schema is defined:

{
  "type": "record",
  "name": "RecursiveRecord",
  "fields": [{"name": "child", "type": "RecursiveRecord"}]
}