Pretty-print object hierarchy in Java?

Question

I'm working on a data analytics project where we are representing a lot of the basic entities you find in a language. I'd like to find a better way to print out their object graphs though for debugging purposes though. So, for example, we might have:

Function: Average
Description: some description
Overload #1:
    parameter-set: paramset-a
        columns: 
           currency: string
           value: double
           scale: integer
    result-set: result-set-a
    preference: first-find
Overload #2: ...
Overload #3: ...

---

My Question

Let's say, in the above example, Function is my root object. Function has some attributes and a series of overloads, each with their own attributes and child objects.

Is there a library that can help me to print the object graph under a root function, in a well-formatted way?

PS: The above example is relatively trivial; in many of our cases, the object hierarchies are 6-10 levels deep, and that's when the real problem comes in.

Answer 1

This is far from perfect, but this question really deserves an answer.

https://github.com/EsotericSoftware/jsonbeans is one way to kind of accomplish something like this. It converts arbitrary Java objects (without having to annotate the fields or anything) to JSON, and includes a pretty-printing method. It can do approximately what you are asking for.

Using this library, you can do something like this:

Json json = new Json();
System.out.println(json.prettyPrint(person));

For some example data, the output you might get looks like this:

{
"name": "Nate",
"age": 31,
"numbers": [
   {
      "name": "Home",
      "class": "com.example.PhoneNumber",
      "number": "206-555-1234"
   },
   {
      "name": "Work",
      "class": "com.example.PhoneNumber",
      "number": "425-555-4321"
   }
]
}