Java Doc for MarkupContainer.java in  » J2EE » wicket » wicket » Java Source Code / Java DocumentationJava Source Code and Java Documentation

• Children - Children can be added by calling the add() method, and they can be looked up using a dotted path. For example, if a container called "a" held a nested container "b" which held a nested component "c", then a.get("b.c") would return the Component with id "c". The number of children in a MarkupContainer can be determined by calling size(), and the whole hierarchy of children held by a MarkupContainer can be traversed by calling visitChildren(), passing in an implementation of Component.IVisitor.
• Markup Rendering - A MarkupContainer also holds/references associated markup which is used to render the container. As the markup stream for a container is rendered, component references in the markup are resolved by using the container to look up Components in the container's component map by id. Each component referenced by the markup stream is given an opportunity to render itself using the markup stream.

  Components may alter their referring tag, replace the tag's body or insert markup after the tag. But components cannot remove tags from the markup stream. This is an important guarantee because graphic designers may be setting attributes on component tags that affect visual presentation.

  The type of markup held in a given container subclass can be determined by calling getMarkupType(). Markup is accessed via a MarkupStream object which allows a component to traverse ComponentTag and RawMarkup MarkupElements while rendering a response. Markup in the stream may be HTML or some other kind of markup, such as VXML, as determined by the specific container subclass.

  A markup stream may be directly associated with a container via setMarkupStream. However, a container which does not have a markup stream (its getMarkupStream() returns null) may inherit a markup stream from a container above it in the component hierarchy. The findMarkupStream() method will locate the first container at or above this container which has a markup stream.

  All Page containers set a markup stream before rendering by calling the method getAssociatedMarkupStream() to load the markup associated with the page. Since Page is at the top of the container hierarchy, it is guaranteed that findMarkupStream will always return a valid markup stream.
  See Also:   MarkupStream
  author:
     Jonathan Locke

Be careful when overriding this method, if not implemented properly it may lead to a java component hierarchy which no longer matches the template hierarchy, which in turn will lead to an error.
Parameters:
  child - The child
throws:
  IllegalArgumentException - Thrown if a child with the same id is replaced by the addoperation.

Be careful when overriding this method, if not implemented properly it may lead to a java component hierarchy which no longer matches the template hierarchy, which in turn will lead to an error.
Parameters:
  child - The child
throws:
  IllegalArgumentException - Thrown if a child with the same id is replaced by the addoperation. This

The result of all this is that components added with autoAdd() are free from versioning and can add their own children without the usual exception that would normally be thrown when the component hierarchy is modified during rendering.
Parameters:
  component - The component to add True, if component has been added

See Also:   wicket.markup.resolver.ParentResolver false. By default a MarkupContainer is not transparent.

Note: it will only called once, the IResourceStream will be cached by MarkupCache.

Note: IResourceStreamLocators should be used in case the strategy to find a markup resource should be extended for ALL components of your application.
See Also:   wicket.util.resource.locator.IResourceStreamLocator
See Also:   wicket.markup.MarkupCache
Parameters:
  containerClass - The container the markup should be associated with A IResourceStream if the resource was found

Note: implementation does not call MarkupContainer.remove(Component) for each component.