Package jakarta.faces.view.facelets

Class MetaTagHandler

java.lang.Object
jakarta.faces.view.facelets.TagHandler
jakarta.faces.view.facelets.MetaTagHandler
All Implemented Interfaces:
FaceletHandler
Direct Known Subclasses:
DelegatingMetaTagHandler, MetaTagHandlerImpl
public abstract class MetaTagHandler
extends TagHandler

Every kind of markup element in Facelets VDL that has attributes that need to take action on a Jakarta Server Faces Java API artifact is associated with an instance of this class. This class is an abstraction to enable a rule based method for directing how different kinds of elements take different kinds of actions in the Jakarta Server Faces Java API. For example, consider this markup: 

 <h:inputText value="#{user.userid}"
 valueChangeListener="#{user.newUserId}" />

This markup element corresponds to an instance of HtmlInputText in the view. HtmlImputText has a number of attributes that are to be exposed to the page author. HtmlInputText also implements EditableValueHolder, which extends ValueHolder. Each of these interfaces also expose a number of attributes to the page author.

Facelets employes the strategy pattern to allow the manner in which all possible attributes are handled based on the nature of the Jakarta Server Faces Java API artifact associated with the markup element.

Subclasses override the createMetaRuleset(java.lang.Class) method to return a MetaRuleset instance encapsulating all the strategies for all the attributes that make sense for this particular markup element. The runtime calls the setAttributes(FaceletContext, Object) method to cause those rules to be executed and applied.

Since:
2.0

  • Constructor Details

    • MetaTagHandler

      public MetaTagHandler​(TagConfig config)
      Constructor.
      Parameters:
      config - the tag configuration.

  • Method Details

    • createMetaRuleset

      protected abstract MetaRuleset createMetaRuleset​(Class type)
      Extend this method in order to add your own rules.
      Parameters:
      type - the type.
      Returns:
      the MetaRuleset.

    • setAttributes

      protected void setAttributes​(FaceletContext ctx, Object instance)
      Invoking/extending this method will cause the results of the created MetaRuleset to auto-wire state to the passed instance.
      Parameters:
      ctx - the Facelet context.
      instance - the instance.