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Extend the default meta-model

Automated Forms Conversion service identifies and extracts form objects from source forms. Semantic mapper helps the service to decide how the extracted objects are represented in an adaptive form. For example, a source form can have many different types of representations of a date. The semantic mapper helps map all the representations of date form objects of the source form with date component of the adaptive forms. Semantic mapper also allows the service to pre-configure and apply validations, rules, data patterns, Help text, and accessibility properties to adaptive form components during conversion.
Meta-model is a JSON schema. Before you start with meta-model, ensure that you are well versed with JSON. You must have experience in creating, editing, and reading data saved in JSON format.

Default meta-model

Automated Forms Conversion service has a default meta-model. It is a JSON schema and resides on Adobe Cloud with other components of Automated Forms Conversion service. You can find a copy of the meta-model on your local AEM server at: http://<server>:<port>/aem/forms.html/content/dam/formsanddocuments/metamodel/global.schema.json. You can also click here to access or download the default schema.
The schema of meta-model is derived from schema entities at https://schema.org/docs/schemas.html. It has Person, PostalAddress, LocalBusiness, and more entities as defined on https://schema.org. Every entity of the meta-model adheres to the JSON schema object type. The following code represents a sample meta-model structure:
   "Entity": {
      "id": "Entity",
      "properties": {
        "name": {
          "type": "string"
        },

        "description": {
          "type": "string",
          "description": "Description of the item"
        }
      }
    }

Download the default meta-model

Perform the following steps to download the default meta-model to the local file system:
  1. Log in to your AEM Forms instance.
  2. Navigate to the Forms > Forms & Documents > Meta Model folder.
  3. Select the global.schema.json file and tap Download . A download dialog box appears. Select the Download asset(s) as binary files option. Tap Download . An archive is downloaded.

Understanding the meta-model

A meta-model refers to a JSON schema file that contains entities. All entities in the JSON schema file include a name and an id. Each entity can include multiple properties. The entities and its properties can vary based on the domain. You can augment a schema file with keywords and field configurations to map schema properties to adaptive form components.
"Event": {
      "id": "Eventid",
      "allOf": [
        {
          "$ref": "#Entity"
        },
        {
          "properties": {
            "startDate": {
              "type": "string",
              "format": "date",
              "description": "Specify the start date and time of the event in ISO 8601 date format."
            },
            "endDate": {
              "type": "string",
              "format": "date",
              "description": "Specify the end date and time of the event in ISO 8601 date format."
            },
            "location": {
              "$ref": "#PostalAddress",
              "description": "Specify the location of the event."
            }
          }
        }
      ]
    }

In this example, Event represents the name of an entity with a value for id as Eventid . The Event entity includes multiple properties:
  • startDate
  • endDate
  • location
The allOf construct in the meta-model enables inheritance among entities.
Each property can further include:
Based on the keywords referenced using aem:affKeyword , the conversion service performs a search operation on the source form fields. The conversion service applies the JSON schema properties and additional properties to the fields that meet the search criteria.
In this example, the conversion service searches for the phone, telephone, mobile phone, work phone, home phone, telephone number, telephone no, and phone number keywords in the source form. Based on the fields that include these keywords, the conversion service applies the type, pattern, and aem:afProperties to the adaptive form fields after conversion.

JSON schema properties for generated adaptive form fields

The meta-model supports the following JSON schema common properties for adaptive form fields generated using the Automated Forms Conversion service:
Property Name Description
title
The text mentioned within the title property in a meta-model serves as a search keyword to perform actions on the generated adaptive form fields. For example, modifying the label of an adaptive form field. For more information, see Modify the label of a form field in Custom meta-model examples.
description
The description property sets the Help text for the generated adaptive form field. For more information, see Add Help text to a form field in Custom meta-model examples.
type
The type property defines the data type for the generated adaptive form field. The possible values for the title property include:
  • string: Generates an adaptive form field of text data type.
  • number: Generates an adaptive form field of numeric data type.
  • integer: Generates an adaptive form field of numeric data type with sub-type set to integer.
  • boolean: Generates a switch adaptive form component.
For more information on using the type property in a meta-model, see Modify the type of a form field in Custom meta-model examples.
pattern
The pattern property restricts the value for the generated adaptive form field based on a regular expression. For example, the following code in the meta-model restricts the value for the generated adaptive form field to ten digits: "pattern": "/\\d{10}/" Similarly, the following code in the meta-model restricts the value of a field to a specific date format. "pattern": "date{DD MMMM, YYYY}",
format
The format property restricts the value for the generated adaptive form field based on a named pattern instead of a regular expression. The possible values for the format property include:
  • email: Generates an email adaptive form component.
  • hostname: Generates a textbox adaptive form component.
For more information on using the format property in a meta-model, see Modify the format of a form field in Custom meta-model examples.
enum and enumNames
The enum and enumNames properties restrict the values of drop-down, check box, or radio button fields to a fixed set. Values listed in enumNames are displayed on the user interface. The values listed using the enum property are used for calculation. For more information, see Convert a form field to multiple-choice check boxes in the adaptive form , Convert a text field to drop-down list in the adaptive form , and Add additional options to the drop-down list in Custom meta-model examples.

Keyword-based search to apply properties to generated adaptive form fields

Automated Forms Conversion service performs a keyword search on the source form during conversion. After filtering the fields that meet the search criteria, the conversion service applies the properties defined for those fields in the meta-model to the generated adaptive form fields.
Keywords are referenced using the aem:affKeyword property.
{
  "numberfields": {
      "type": "number",
      "aem:affKeyword": ["Bank account number"]
 }
}

In this example, the conversion service uses the text within aem:affKeyword as a search keyword. After retrieving the Bank account number text in the form, the conversion service converts the field into a number type using the type property.

Additional properties for generated adaptive form fields

You can use the aem:afProperties property in the meta-model to define following additional properties for adaptive forms fields generated using Automated Forms Conversion service:
Property Name Description
multiLine
The multiLine property converts a source form field into a multi-line field in the adaptive form after conversion. For more information, see Convert a string field to a multi-line field in Custom meta-model examples.
mandatory
The mandatory property sets the input for an adaptive form field after conversion as mandatory. For more information, see Add validations to adaptive form fields in Custom meta-model examples.
jcr:title
The jcr:title property, with the title JSON schema property, enables you to modify the label of an adaptive form field after conversion. For more information, see Modify the label of a form field in Custom meta-model examples. See Creating adaptive forms using JSON schema for information on more properties that you can apply to adaptive form fields using JSON schema.
sling:resourceType and guideNodeClass
sling:resourceType and guideNodeClass properties enable you to map a form field to a corresponding adaptive form component. For more information, see Convert a form field to multiple-choice check boxes in the adaptive form and Convert a text field to drop-down list in the adaptive form in Custom meta-model examples.
validatePictureClause
The validatePictureClause property sets a validation on the format allowed in the adaptive form field after conversion. For more information, see Add validations to adaptive form fields in Custom meta-model examples.
#custommetamodelexamples

Modify adaptive form fields using custom meta-model

Your organization can have patterns and validations in addition to the ones listed in the default meta-model. You can extend the default meta-model to add pattern, validations, and entities specific to your organization. Automated Forms Conversion service applies the custom meta-model to the form fields during conversion. You can keep updating the meta-model as new patterns, validations, and entities specific to your organization are discovered.
Automated Forms Conversion service uses a default meta-model saved at the following location to map source form fields to the adaptive form fields during conversion:
http://<server>:<port>/aem/forms.html/content/dam/formsanddocuments/metamodel/global.schema.json
However, you can save a custom meta-model in a folder and modify the conversion service properties to use the custom meta-model during conversion.

Use custom meta-model during conversion

Execute the following steps to use a custom meta-model during conversion:
  1. Create a folder in Forms > Forms & Documents and upload the custom meta-model JSON schema file to the folder.
  2. Open the conversion service properties using:
    Tools > Cloud Services > Automated Forms Conversion Configuration > < Properties of selected configuration >
  3. In the Basic tab, specify the location of the custom meta-model in the Custom Meta-model field and tap Save & Close .
  4. Run the conversion to apply the custom meta-model to the conversion process.

Custom meta-model examples

Some common examples of using a custom meta-model to modify adaptive form field properties include:
  • Modify the label of a form field
  • Modify the type of a form field
  • Add Help text to a form field
  • Convert a form field to multiple-choice radio buttons in the adaptive form
  • Modify the format of a form field
  • Add validations to adaptive form fields
  • Convert a form field to drop-down list options in the adaptive form
  • Add additional options to the drop-down list
  • Convert a string field to a multi-line field

Modify the label of a form field

Example: Modify the Bank account number label in the form to Custom account Number in the adaptive form after conversion.
In this custom meta-model, the conversion service uses the title property as a search keyword. After retrieving the Bank account number text in the form, the conversion service replaces the text with the Customer account number string mentioned with the jcr:title property in the aem:afProperties section.
{
  "numberfields": {
      "type": "number",
   "title": "Bank account number",
   "aem:afProperties" : {
    "jcr:title" : "Customer account number"
   }
   }
}

Modify the type of a form field

Example : Modify the Bank account number field of text type in the form before conversion to a number type field in the adaptive form after conversion.
In this custom meta-model, the conversion service uses the text within aem:affKeyword as a search keyword. After retrieving the Bank account number text in the form, the conversion service converts the field into a number type using the type property.
{
  "numberfields": {
      "type": "number",
      "aem:affKeyword": ["Bank account number"]
 }
}

Add Help text to a form field

Example : Add Help text to the Bank account number field of adaptive form.
In this custom meta-model, the conversion service uses the text within aem:affKeyword as a search keyword. After retrieving the Bank account number text in the form, the conversion service adds the Help text to the adaptive form field using the description property.
{
  "numberfields": {
      "type": "number",
      "aem:affKeyword": ["Bank account number"],
   "description": "Specify your bank account number."
 }
}

Convert a form field to multiple-choice check boxes in the adaptive form

Example : Convert the Country field of string type in the form before conversion to check boxes in the adaptive form after conversion.
In this custom meta-model, the conversion service uses text within aem:affKeyword as a search keyword. After retrieving the Country text in the form, the conversion service converts the field into following check boxes using the enum property:
  • India
  • England
  • Australia
  • New Zealand
sling:resourceType and guideNodeClass properties map a form field to the check box adaptive form component.
{
"title": {
    "aem:affKeyword": [
      "country"
    ],
    "type" : "string",
    "enum": [
      "India",
      "England",
      "Australia",
      "New Zealand"
    ],
    "aem:afProperties": {
      "sling:resourceType": "fd/af/components/guidecheckbox",
      "guideNodeClass": "guidecheckbox"
    }
  }
}

Modify the format of a form field

Example : Modify the format of the Email Address field to an email format.
In this custom meta-model, the conversion service uses text within aem:affKeyword as a search keyword. After retrieving the Email Address text in the form, the conversion service converts the field into an email format using the format property.
{
   "additionalDetails" : {
      "aem:affKeyword": ["E-mail Address"],
       "type" : "string",
       "format" : "email"
  } 
}

Add validations to adaptive form fields

Example 1: Add a validation to the Postal Code field of the adaptive form.
In this custom meta-model, the conversion service uses text within aem:affKeyword as the search keyword. After retrieving the Postal Code text in the form, the conversion service adds a validation to the field using the validatePictureClause property defined in the aem:afProperties section. Based on the validation, the input that you specify for the Postal Code field in the adaptive form after conversion must include six characters.
{
   "postalCode" : {
      "aem:affKeyword": ["Postal Code"],
      "type" : "string",
      "aem:afProperties" : {
        "validatePictureClause" : "\\d{6}"
      } 
   }
}

Example 2: Add a validation to the Bank account number field of the adaptive form.
In this custom meta-model, the conversion service uses text within aem:affKeyword as the search keyword. After retrieving the Bank account number text in the form, the conversion service adds a validation to the field using the mandatory property defined in the aem:afProperties section. Based on the validation, you must specify a value for the Bank account number field before submitting the form after conversion.
{
  "numberfields": {
      "type": "number",
      "aem:affKeyword": ["Bank account number"],
   "aem:afProperties" : {
        "mandatory": "true"
      }   
   }
}

Convert a text field to drop-down list in the adaptive form

Example : Convert the Country field of string type in the form before conversion to drop-down options in the adaptive form after conversion.
In this custom meta-model, the conversion service uses text within aem:affKeyword as the search keyword. After retrieving the Country text in the form, the conversion service converts the field into following drop-down list options using the enum property:
  • India
  • England
  • Australia
  • New Zealand
sling:resourceType and guideNodeClass properties map a form field to the drop-down adaptive form component.
{
"title": {
    "aem:affKeyword": [
      "country"
    ],
    "type" : "string",
    "enum": [
      "India",
      "England",
      "Australia",
      "New Zealand"
    ],
    "aem:afProperties": {
      "sling:resourceType": "fd/af/components/guidedropdownlist",
      "guideNodeClass": "guideDropDownlist"
    }
  }
}

Add additional options to the drop-down list

Example: Add Sri Lanka as an extra option to an existing drop-down list using a custom meta-model.
To add an extra option, update the enum property with the new option. In this example, update the enum property with Sri Lanka as an extra option. Values listed in enum property display in the drop-down list.
{
"title": {
    "aem:affKeyword": [
      "country"
    ],
    "type" : "string",
    "enum": [
      "India",
      "England",
      "Australia",
      "New Zealand",
   "Sri Lanka"
    ],
    "aem:afProperties": {
      "sling:resourceType": "fd/af/components/guidecheckbox",
      "guideNodeClass": "guidecheckbox"
    }
  }
}

Convert a string field to a multi-line field

Example: Convert the Address field of string type to a multi-line field in the form after conversion.
In this custom meta-model, the conversion service uses text within aem:affKeyword as the search keyword. After retrieving the Address text in the form, the service converts the text field to a multi-line field using the multiLine property defined in the aem:afProperties section.
{
 "multiLine" : {
   "aem:affKeyword": [
      "Address"
    ],
    "type" : "string",
    "aem:afProperties": {
      "multiLine": "true"
    }
  }
}