> For the complete documentation index, see [llms.txt](https://docs.fractalworks.io/joule/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fractalworks.io/joule/concepts/key-joule-data-types/contextual-data.md).

# Contextual data

## Overview

[Contextual data](/joule/components/contextual-data.md) provides additional context to support advanced stream processing use cases.

Joule offers a base implementation for storing contextual data elements, enabling the **development of custom components** that are both **efficient and flexible** in processing external data within the platform.

The `ReferenceDataObject` extends the `HashMap<String, Object>`, providing the **full benefits of a map structure** while adding extensions specifically designed for **storing and querying** contextual data.

This data structure allows for **seamless integration and management of contextual information** across Joule's platform.

## Key features

1. <mark style="color:green;">**Extends HashMap**</mark>\
   Inherits all features of `HashMap<String, Object>`, offering a flexible key-value data structure.
2. <mark style="color:green;">**Contectual data storage**</mark>\
   Designed for storing and querying contextual reference data efficiently.
3. <mark style="color:green;">**Custom data representation**</mark>\
   Supports storing and retrieving custom data, providing flexibility for various use cases.

## Build with the SDK

{% content-ref url="/pages/fBCARp3hs0REBtAX9rzX" %}
[ReferenceDataObject](/joule/developer-guides/builder-sdk/data-types/referencedataobject.md)
{% endcontent-ref %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.fractalworks.io/joule/concepts/key-joule-data-types/contextual-data.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.