> For the complete documentation index, see [llms.txt](https://bpmflow.gitbook.io/project/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bpmflow.gitbook.io/project/engineering-models/4+1-architecture-models/logical-view/orbeon-form-model.md).

# Orbeon Form Model

**UML Class Model**

![](https://3974112602-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LH4gGgyMb1_fhOg782r%2F-LHEnC4kq7wvGsELcMjz%2F-LHEm1yrqN2WYBJmM2NW%2Fuml.jpg?alt=media\&token=d1f9d4c5-0466-4f05-a46e-a0ce87e5fe5c)

Each instance of **OrbeonApplication** holds a **Dictionary** where each key is a ***"form-name"*** and each value is an **aFormDefinitionRegistry**. Each **FormDefinitionRegistry** has three collections holding \[currentVersions] (the latest), \[old versions] overwrote definitions and saved definitions (some not published yet).

![](https://3974112602-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LH4gGgyMb1_fhOg782r%2F-LHEnC4kq7wvGsELcMjz%2F-LHEmSZGKkcYV1JOdCHT%2Fapplications.png?alt=media\&token=34bb93fc-a580-4f93-81e1-05ac16735c30)

The following diagram depicts how high performance is achieved. Each **FormDefinition** has a **Dictionary** where the key is the ***"field-name"*** and each value is anIdexableCollection (**RcIdentityBag**). Each collection hold all instance values of an individual field.\
See:\
 `OrbeonFormInstance>>generateFormFieldValueSet`\
`OrbeonPublishedFormDefinition>>updateFieldInstancesFrom:`

![](https://3974112602-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LH4gGgyMb1_fhOg782r%2F-LHEnC4kq7wvGsELcMjz%2F-LHEmauuanyYO5Zm8dzp%2Fforms-definitions.png?alt=media\&token=c1dbd9ab-683f-42aa-9086-2ab230132605)

 The following diagram depicts **FormFieldValues** inside a **FormInstance.**\
See: `AppFieldValueHolder>>processFieldValueCollection: withFieldClass:in:`

![](https://3974112602-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LH4gGgyMb1_fhOg782r%2F-LHEnC4kq7wvGsELcMjz%2F-LHEmeiD0ilB6iOLEGOI%2Fform-instance-struc.jpg?alt=media\&token=a0bd70fa-dbdb-462a-ae52-ba911b08f4d8)