Package org.zkoss.zk.ui

Interface IdSpace

All Superinterfaces:
Scope
All Known Subinterfaces:
Macro, Page
All Known Implementing Classes:
AbstractPage, HtmlMacroComponent, PageImpl, VolatilePage
public interface IdSpace extends Scope
Implemented by a component (Component) and a page (Page) to denote that all its descendant and itself forms an independent ID space.

In an ID space, ID of each component (Component.getId()) must be unique. And, you could retrieve any component in the same ID space by calling getFellow(java.lang.String) upon any component of the same ID space.

For sake of description, components in the same ID space are called fellows. If the component has an ancestor which implements IdSpace, we say a component belongs to the ID space owned by the ancestor. If no such ancestor exists, the component belongs to the ID space owned by the page. The ancestor and the page is called the owner (Component.getSpaceOwner()).

For sake of description, we also call the ID space as space X, if the owner is component X (or page X). If component Y is a child of X and also implements IdSpace (a.k.a., another owner), then space X includes component Y, but EXCLUDES descendants of Y. In other words, Y belongs to space X and space Y. Thus, to get a child Z in the Y space, you shall X.getFellow('Y').getFellow('Z').

Example: Assumes component A is a child of B, B a child of C and C a child of D. If only C implements IdSpace, A, B and C are all belonged to the C space. D doesn't belong any space.

If both C and D implements IdSpace, C and D belongs to the D space while A, B and C belongs to the C space.

Note: to make a component (deriving from AbstractComponent) an ID space owner, all it needs to do is to implement this interface.

Author:
tomyeh

  • Method Details

    • getFellow

      Component getFellow(String id) throws ComponentNotFoundException
      Returns a component of the specified ID in this ID space. Components in the same ID space are called fellows.

      Unlike getFellowIfAny(String), it throws ComponentNotFoundException if not found.

      Throws:
      ComponentNotFoundException - is thrown if this component doesn't belong to any ID space

    • getFellow

      Component getFellow(String id, boolean recurse) throws ComponentNotFoundException
      Returns a component of the specified ID in this ID space.

      Unlike getFellowIfAny(String, boolean), it throws ComponentNotFoundException if not found.

      Parameters:
      recurse - whether to look up the parent ID space for the existence of the fellow
      Throws:
      ComponentNotFoundException - is thrown if this component doesn't belong to any ID space
      Since:
      5.0.0

    • getFellowIfAny

      Component getFellowIfAny(String id)
      Returns a component of the specified ID in this ID space, or null if not found.

      Unlike getFellow(String), it returns null if not found.

    • getFellowIfAny

      Component getFellowIfAny(String id, boolean recurse)
      Returns a component of the specified ID in this ID space, or null if not found.

      Unlike getFellow(String, boolean), it returns null if not found.

      Parameters:
      recurse - whether to look up the parent ID space for the existence of the fellow
      Since:
      5.0.0

    • getFellows

      Collection<Component> getFellows()
      Returns all fellows in this ID space. The returned collection is readonly.
      Since:
      3.0.6

    • hasFellow

      boolean hasFellow(String id)
      Returns whether there is a fellow named with the specified component ID.
      Since:
      3.5.2

    • hasFellow

      boolean hasFellow(String id, boolean recurse)
      Returns whether there is a fellow named with the specified component ID.
      Parameters:
      recurse - whether to look up the parent ID space for the existence of the fellow
      Since:
      5.0.0