Managing Dynamic Attributes - CUBA Platform. Developer’s Manual

5.9.1.1. Managing Dynamic Attributes

Managing attributes categories and descriptions is done via special screens available in Administration > Dynamic Attributes menu.

The category browser shows the list of all registered categories.

Figure 27. Categories Browser

The category editor allows you to create a new category for an entity and define a set of dynamic attributes. The category name and the related entity type fields are mandatory. The Default checkbox indicates that this category will be automatically selected for a new instance of an entity implementing Categorized interface.

Figure 28. Category Editor

The Name localization groupbox is shown if the application supports more than one language. It enables setting the localized values of category names for each available locale.

Figure 29. Category name localization

Dynamic attribute editor enables setting the name, system code, value type and the default value of the attribute.

Figure 30. Dynamic Attribute Editor

For all value types, except Boolean, there is a Width field available to set up the field width in FieldGroup in pixels or as a percentage. If the Width field is empty, its assumed value is 100%.

For all value types, except Boolean and Enumeration, there is also an Is collection checkbox available. It allows you to create multi-valued dynamic attributes of a selected type.

Localization is supported for all types of dynamic attributes:

Figure 31. Dynamic Attribute Localization

For the Enumeration value type, the set of named values is defined in the Enumeration field via the list editor.

Figure 32. Dynamic Attribute Editor for Enumeration type

Each enumeration value can also be localized to the languages, available for the application.

Figure 33. Dynamic Attribute Localization for Enumeration type

A dynamic attribute also has visibility settings, which define the screens where it should be displayed. By default, the attribute is invisible on any screen.

Figure 34. Dynamic Attribute Visibility Settings

In addition to the screen, you can also specify a component in which the attribute is to appear (for example, for screens, where several FieldGroup components show the fields of the same entity).

If the attribute is marked as visible on a screen, it will automatically appear in all field groups and tables displaying entities of the corresponding type on the screen.

Access to dynamic attributes can also be restricted by user role settings. Security settings for dynamic attributes are similar to those for regular attributes.

In order for changes in attribute and visibility settings to take effect, click Apply settings in the categories browser. Changes can also be applied via Administration > JMX Console by calling the clearDynamicAttributesCache() method of the app-core.cuba:type=CachingFacade JMX bean.

The dynamic attribute added to the screen automatically by specifying visibility settings is shown below:

Dynamic attributes can be added to a screen manually. To do this, follow these steps:

In the dsContext section of the screen XML-descriptor, set the loadDynamicAttributes property to true for a datasource that loads the entity (entities), for example:
```
<dsContext>
    <datasource id="carDs" class="com.company.sample.entity.Car" view="_local" loadDynamicAttributes="true"/>
</dsContext>
```
Specify the dynamic attribute code with the + prefix in the property XML attribute of a component definition:
```
<textField id="numberOfSeats" datasource="carDs" property="+numberOfSeats"/>
```