javax.faces.component
Interface NamingContainer

All Known Implementing Classes:

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.

Version:

$Revision: 685651 $ $Date: 2008-08-13 14:36:16 -0500 (Wed, 13 Aug 2008) $

Author:

Manfred Geiler (latest modification by $Author: skitching $)

Field Summary

static char

SEPARATOR_CHAR

Field Detail

SEPARATOR_CHAR

static final char SEPARATOR_CHAR

See Also:

Constant Field Values