Creating a form field data resolver

FormIO forms in Valtimo can be prefilled with data from custom sources.

Form field data resolvers have been deprecated as of version 11.0.0 and will be removed in the future. Please use value resolvers instead.

Introduction

A FormFieldDataResolver is a spring bean that is used by Valtimo to get data to be preloaded in a form. By adding a new implementation of the FormFieldDataResolver interface and registering this as bean, a new prefix can be supported.

Implementing the FormFieldDataResolver

There are two methods that need to be implemented:

• The supports(String externalFormFieldType) method determines if the current resolver is applicable for a certain prefix. When true is returned, it means the current resolver supports the prefix that Valtimo has found and the get method will be called.

• The get(String documentDefinitionName, UUID documentId, String... varNames) method is used by Valtimo get retrieve the actual data. documentDefinitionName and documentId are passed in as context that can be used to find the data for the current form. Any fields in the form that use the same prefix will be bundled and passed into this method as the varargs parameter varNames. The intention is to be able to combine and reduce calls to other systems and resources in order to reduce load and load times (e.g. retrieve a database record once, and get multiple properties from the result). The result of this method is a Map<String, Object> where the key is the name of the field (one entry from the varNames) and the value is the value that needs to be loaded in the form.

Below is an example of a FormFieldDataResolver. This example would be called for each form field where the example prefix is used (e.g. example:some-field).

class ExampleDataResolver : FormFieldDataResolver {
    
    override fun supports(externalFormFieldType: String): Boolean {
        return externalFormFieldType == PREFIX
    }

    @Override
    override fun get(documentDefinitionName: String, documentId: UUID, vararg varNames: String): Map<String, Object> {
        // get values for all requested variables
    }

    companion object {
        private const val PREFIX = "example"
    }
}