Components are independent and reusable parts used in SAPUI5 applications.
An application can use components from different locations from where the application is running. Thus, components can be developed by different development teams and be used in different projects. Components also support the encapsulation of closely related parts of an application into a particular component. This makes the structure of an application and its code easier to understand and to maintain.
SAPUI5 provides the following two types of components:
Faceless components (class: sap.ui.core.Component)
Faceless components do not have a user interface and are used, for example, for a service that delivers data from a back-end system.
UI components (class: sap.ui.core.UIComponent)
UI components extend components and add rendering functionality to the component. They represent a screen area or element on the user interface, for example, a button or a shell, along with the respective settings and metadata. sap.ui.core.UIComponent extends sap.ui.core.Component and adds rendering functionality to the component.
The sap.ui.core.Component class is the base class for UI and faceless components and provides the metadata for both types of components. To extend the functionality, components can inherit from their base class or from another component.
Components are loaded and created via the component factory function sap.ui.component. You can either pass the name of the component or the URL of the descriptor file (manifest.json) to load it via the descriptor, see Manifest First Function. We recommend loading the component using the descriptor (if available) - it improves performance during the initial load since the loading process can be parallelized and optimized.
After loading the descriptor, the component factory can load the dependencies (SAPUI5 libraries and other dependent components) in parallel next to the component preload, and also models can be preloaded.
A component is organized in a unique namespace, the namespace of the component equals the component name.
Optional resources are, for example, CSS, js, or i18n files, views, controllers)
The following figure gives an example of a component folder structure.
The ComponentContainer control wraps a UI component. You use the ComponentContainer control in the SAPUI5 control tree in the same way as any other control.
The following list explains how other concepts used in SAPUI5 are distinguished from the SAPUI5 components concept:
Both concepts provide a set of controls behind a single interface. Composite controls are intended for reuse within control development and allow to include existing controls in a complex control whereas components are intended for reuse in application development.
The UI library is the deployable unit around controls: Controls are never deployed standalone, but as part of a control library. Components, however, are self-contained and should not be used to deploy controls.
A notepad control is another way to define a control. Notepad controls have all the characteristics of a control.
The MVC concept allows to define views and controllers and, thus, to structure and reuse parts within an application. As MVC can only be deployed separately and has no means to define dependent styles or scripts that are loaded together with a view, this concept is of limited use across different applications.
ApplicationApplications have a single start URL and contain everything belonging to the application in a deployable unit. However, it is not possible to embed an application into another application as the knowledge about the required libraries, scripts and additional style sheets is contained in the index.html.