Package jakarta.faces.component

Interface NamingContainer

  • All Known Implementing Classes:
    HtmlDataTable, HtmlForm, UIData, UIForm, UINamingContainer
    public interface NamingContainer
    Interface implemented by components that provide a new "namespace" for the ids of their child components.

    Component ids must be unique between all descendants of a NamingContainer; the JSF library will report a fatal error and refuse to process or render any view where two components in the same NamingContainer have identical id values. However a component that is a descendant of one NamingContainer component is permitted to have the same id as a component that is a descendant of a different NamingContainer component.

    Unique component ids are used to:

    • generate unique names for HTML form fields, etc
    • search for components via UIComponent.findComponent(String expr)
    • on re-render after postback, match up component declarations in the view templates with existing components in the restored view tree.

    Requiring every component in a large view (which is possibly built by including or composing multiple files together) to have an id which is different from every other id is simply unmanageable; JSF certainly must provide some kind of id namespacing. Therefore this base class is defined, and a few standard JSF components subclass it (in particular, f:subview).

    When generating clientId values during rendering, descendants of a NamingContainer instance are allocated a clientId which is their own id prefixed with the clientId of the ancestor NamingContainer, eg "parentId:childId". NamingContainer components can be nested within other NamingContainer components, generating clientIds like "firstId:middleId:leafId".

    Not every component is a naming container; that would technically work, but the clientId values generated would quickly grow excessively long.

    See the javadoc for this class in the JSF Specification for further details.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static char SEPARATOR_CHAR
      The separator character used in component identifiers to demarcate navigation to a child naming container.

    • Field Detail

      • SEPARATOR_CHAR

        static final char SEPARATOR_CHAR

        The separator character used in component identifiers to demarcate navigation to a child naming container. The default separator character used in component identifiers to demarcate navigation to a child naming container, in case UINamingContainer.getSeparatorChar(jakarta.faces.context.FacesContext) does not resolve to a valid value. It is not recommended to use this value directly, the {link UINamingContainer#getSeparatorChar(jakarta.faces.context.FacesContext)} must be used instead.

        See Also:
        Constant Field Values