This interface is a marker interface. A marker interface is a signal to the component’s container to add the interface’s behavior to the component. You don’t need to implement any specific methods or attributes in your component, you simply add the interface name to the component’s implements attribute.
<aura:attribute name="sObjectName" type="String" />
The sObjectName attribute is set only when you place or invoke the component in a context of a record. For example, when you place the component on a record page, or invoke it as an action from a record page or object home. In all other cases, such as when you create this component programmatically inside another component, sObjectName isn’t set, and your component shouldn’t depend on it.
This example shows the markup required to add the force:hasSObjectName interface to a Lightning component.
<aura:component implements="force:lightningQuickAction,force:hasSObjectName"> <!-- ... --> </aura:component>
The component’s controller can access the ID of the current record from the recordId attribute, using component.get("v.sObjectName"). The recordId attribute is automatically added to the component by the force:hasSObjectName interface.