Package org.zkoss.zk.ui.util

Class Composition

java.lang.Object
org.zkoss.zk.ui.util.Composition
All Implemented Interfaces:
Initiator, InitiatorExt
public class Composition extends Object implements Initiator, InitiatorExt

Composition manager that compose the given components into a whole page per the "insert" components and "define" components annotations. The "define" components will attach itself on to the "insert" component with the same annotated joinId. That is, the "insert" component is the parent component of the "define" components with the same annotated joinId. Note that "insert" components can NOT have duplicate joinId in a page while "define" components can because you can have multiple child components but you cannot have multiple parent components. Also note that a "define" components must be a root component of the page.

This Composition manager is useful when you need to do layout injection or you want to design a common page template across multiple pages.

  • You first design a template with "insert" components telling where the insert points are. Each insert component has to be given a distinguish joinId in a page(e.g. <window self="@{insert(content)}"/> here the "content" is the joinId).
  • Then in the real page, you have root "define" components telling which "define" components are to be attach onto the "insert" component with the same joinId (e.g. <label self="@{define(content)}"; here the "content" is the joinId).
  • This Composition class is designed as a page Initiator and a InitiatorExt, so you have to specify in the real page as following to use it. 
     
 <?init class="org.zkoss.zk.ui.util.Composition" [arg0="TEMPLATE1"[, arg1="TEMPLATE2"]...]?>
 ...
    Where the arg0 ~ argx you can give zul template uri. This implementation use Excecutions.createComponents() to create them and then do the real composition in the InitiatorExt.doAfterCompose(Page, Component[]).
  • If more than one "define" components have the same joinId, they are attached onto the "insert" component in the sequence of the definition.
  • If a "define" component cannot find the corresponding "insert" component, it will be simply detached from the page.
  • Also you can prepare a parent component and pass it in via Execution.getCurrent().setAttribute(Composition.PARENT, parent) then this implementation will attach finally composed root components as the children of the provided parent.
  • If you did not provide the parent component, the finally composed root components are attached directly to the current page.
Since:
3.5.2
Author:
henrichen