---
title: "Configure linked lists"
slug: "create-linked-lists"
updated: 2025-01-08T13:20:48Z
published: 2025-01-08T13:20:48Z
canonical: "docs.grassfish.com/create-linked-lists"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.grassfish.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Configure linked lists

As a spot developer, you can configure a spot with linked lists that are dynamically populated based on the values ​​of other lists. This means dependent dropdown lists, where selecting items from one list affects the available options in another. The lists are dynamically populated with information from a webservice. All you need is the webservice’s URL.

> [!NOTE]
> **Note**
> 
> [Learn more about creating dropdown lists in HTML Wizard spots](https://docs.grassfish.com/docs/en/specify-spot-information#dropdowns).

## Best practices

Before you configure your linked lists, note the following recommendations:

- Specify the dependencies of each linked list correctly, so it can fetch the right data.
- Verify that the API endpoints (URLs) return the expected data format.
- Initialize linked list values ​​to zero and handle cases where dependent data may not be available.

## Configure linked lists

To create linked lists, perform the following steps:

1. Specify the spot [element](https://docs.grassfish.com/docs/specify-spot-information#elements) with the following parameters:

| Setting | Description |
| --- | --- |
| Id | Specify the ID of the element. The ID must be unique. Example: **marketLinkedList** |
| DataType | Specify the type of data that the element contains. Example: **linkedList** |
| DisplayName | Specify the display name of the element. This name appears in the HTML Wizard. Example: **Market** |
2. Configure each list in the element with the following parameters:

| Setting | Description |
| --- | --- |
| Id | Specify the ID of the list. The ID must be unique. Example: **market** |
| DisplayName | Specify the display name of the list. This name appears in the HTML Wizard. Example: **Market** |
| Url | Specify the URL of the webservice (API endpoint) that provides data for the list items. Example: **https://example.com/markets** |
| Dependencies | Specify the IDs of other lists that this list depends on, separated by commas. Example: **["market", "modelGroup"]** |
| Response | Use the response mapping to extract the correct data from the API response. [Example](/grassfish/docs/create-linked-lists#configure-response-data) |
| Entry | Specify the entry point in the API response where the list items are located. [Example](/grassfish/docs/create-linked-lists#configure-response-data) |
| Mapping | Specify the following settings to map the response data to the list item properties: - **Id**: field name for the item’s ID. - **Value**: field name for the item’s name. - **Name**: field name for the item’s display name. [Example](/grassfish/docs/create-linked-lists#configure-response-data) |
| Value | Initialize the value field to hold the selected values for each linked list. Optionally, use **null**. |
| Options | Set additional options like **Required**. |

## Example configuration

Each spot configuration is specified in a JSON structure. The following example is a configuration snippet with linked lists:

```xml
{
  "Document": {
    "Elements": [
      {
        "Id": "marketLinkedList",
        "DataType": "linkedList",
        "DisplayName": "Market",
        "Lists": [
          {
            "Id": "market",
            "DisplayName": "Market",
            "Url": "https://example.com/markets",
            "Dependencies": [],
            "Response": {
              "Entry": "",
              "Mapping": {
                "Id": "market",
                "Value": "market",
                "Name": "market"
              }
            }
          }
        ],
        "Value": {
          "market": null
        },
        "Options": {
          "Required": true
        }
      },
      {
        "Id": "modelRange",
        "DataType": "linkedList",
        "DisplayName": "Model Range",
        "Lists": [
          {
            "Id": "modelGroup",
            "DisplayName": "Model Group",
            "Url": "https://example.com/markets/{market}",
            "Dependencies": ["market"],
            "Response": {
              "Entry": "ranges",
              "Mapping": {
                "Id": "id",
                "Value": "name",
                "Name": "name"
              }
            }
          },
          {
            "Id": "subModelGroup",
            "DisplayName": "Sub Model Group",
            "Url": "https://example.com/markets/{market}/ranges/{modelGroup}",
            "Dependencies": ["market", "modelGroup"],
            "Response": {
              "Entry": "series",
              "Mapping": {
                "Id": "id",
                "Value": "name",
                "Name": "name"
              }
            }
          }
        ],
        "Value": {
          "modelGroup": null,
          "subModelGroup": null
        },
        "Options": {
          "Required": true
        }
      }
    ]
  }
}
```

### What happens in the example?

The example configures the following elements and linked lists:

- The element **marketLinkedList** contains one linked list:
  - The linked list is called **market**.
  - It fetches its items from `https://example.com/markets`.
  - Since there are no dependencies, it can retrieve data independently from other lists.
- The element **modelRange** contains two linked lists:
  - The first linked list is called **modelGroup**. It depends on the list **market** to fetch its items.
  - The second linked list is called **subModelGroup**. It depends on the lists **market** and **modelGroup** to fetch its items.

### Example display

In the HTML Wizard, list lements are displayed as follows:

![](https://cdn.document360.io/e2b87f73-d9f5-43cb-8182-2641762664fd/Images/Documentation/html_wizard_spot_lists.png?sv=2026-02-06&spr=https&st=2026-11-06T20%3A17%3A34Z&se=2026-11-06T21%3A17%3A34Z&sr=c&sp=r&sig=cFKAhhbslQZ5tdWB7xGP66LRlJKqx0O0VkiXDAx0moU%3D)