|
|
| (4 intermediate revisions by 3 users not shown) |
| Line 2: |
Line 2: |
| | | | |
| | == Overview == | | == Overview == |
| − | For scripts embedded in a ZUML page, there are a set of implicit objects that enable developers to access components more efficiently. It's also a mechanism to pass data inter page, application. These objects are available to the Java codes included by the <tt>zscript</tt> element and the attributes for specifying event listeners. They are also available to EL expressions. | + | For scripts embedded in a ZUML page, there are a set of implicit objects that enable developers to access components more efficiently. It's also a mechanism to pass data inter page, application. These objects are available to the Java codes included by the <code>zscript</code> element and the attributes for specifying event listeners. They are also available to EL expressions. |
| | | | |
| − | For example, <tt>self</tt> is an instance of <tt>org.zkoss.zk.ui.Component</tt> to represent the component being processing. In the following example, you could identify the component in an event listener by <tt>self</tt>. | + | For example, <code>self</code> is an instance of <javadoc type="interface">org.zkoss.zk.ui.Component</javadoc> to represent the component being processing. In the following example, you could identify the component in an event listener by <code>self</code>. |
| | | | |
| | <source lang="xml" > | | <source lang="xml" > |
| Line 10: |
Line 10: |
| | </source> | | </source> |
| | | | |
| − | Similarly, <tt>event</tt> is the current event being processed by an event listener. Thus, the above statement is equivalent to | + | Similarly, <code>event</code> is the current event being processed by an event listener. Thus, the above statement is equivalent to |
| | | | |
| | <source lang="xml" > | | <source lang="xml" > |
| Line 17: |
Line 17: |
| | | | |
| | | | |
| − | == List of Implicit Objects ==
| + | {{ZKDevelopersGuideHeadingToc}} |
| | | | |
| − | {| border="1"
| |
| − | ! <center>Object Name</center>
| |
| − | ! <center>Type</center>
| |
| − | ! <center>Description</center>
| |
| − |
| |
| − | |-
| |
| − | | self
| |
| − | | [http://www.zkoss.org/javadoc/3.5.1/zk/org/zkoss/zk/ui/Component.html <tt>org.zkoss.zk.ui.Component</tt>]
| |
| − |
| |
| − | |The component itself.
| |
| − |
| |
| − | |-
| |
| − | | spaceOwner
| |
| − | | [http://www.zkoss.org/javadoc/3.5.1/zk/org/zkoss/zk/ui/idspace.html <tt>org.zkoss.zk.ui.IdSpace</tt>]
| |
| − |
| |
| − | |The space owner of this component. It is the same as <tt>self.spaceOwner</tt>.
| |
| − |
| |
| − | |-
| |
| − | | page
| |
| − | | [http://www.zkoss.org/javadoc/3.5.1/zk/org/zkoss/zk/ui/page.html <tt>org.zkoss.zk.ui.Page</tt>]
| |
| − |
| |
| − | |The page. It is the same as <tt>self.page</tt>.
| |
| − |
| |
| − | |-
| |
| − | | desktop
| |
| − | | [http://www.zkoss.org/javadoc/3.5.1/zk/org/zkoss/zk/ui/desktop.html <tt>org.zkoss.zk.ui.Desktop</tt>]
| |
| − |
| |
| − | |The desktop. It is the same as <tt>self.desktop</tt>.
| |
| − |
| |
| − | |-
| |
| − | | execution
| |
| − | | [http://www.zkoss.org/javadoc/3.5.1/zk/org/zkoss/zk/ui/execution.html <tt>org.zkoss.zk.ui.Execution</tt>]
| |
| − |
| |
| − | |The current execution.
| |
| − |
| |
| − | |-
| |
| − | | session
| |
| − | | [http://www.zkoss.org/javadoc/3.5.1/zk/org/zkoss/zk/ui/session.html <tt>org.zkoss.zk.ui.Session</tt>]
| |
| − |
| |
| − | |The session.
| |
| − |
| |
| − | |-
| |
| − | | application
| |
| − | | [http://www.zkoss.org/javadoc/3.5.1/zk/org/zkoss/zk/ui/webapp.html <tt>org.zkoss.zk.ui.WebApp</tt>]
| |
| − |
| |
| − | |The Web application.
| |
| − |
| |
| − | |-
| |
| − | | componentScope
| |
| − | | <tt>java.util.Map</tt>
| |
| − |
| |
| − | |A map of attributes defined in the component. It is the same as the <tt>getAttributes</tt> method in the <tt>org.zkoss.zk.ui.Component</tt> interface.
| |
| − |
| |
| − | |-
| |
| − | | spaceScope
| |
| − | | <tt>java.util.Map</tt>
| |
| − |
| |
| − | |A map of attributes defined in the ID space containing this component.
| |
| − |
| |
| − | |-
| |
| − | | pageScope
| |
| − | | <tt>java.util.Map</tt>
| |
| − |
| |
| − | |A map of attributes defined in the page. It is the same as the <tt>getAttributes</tt> method in the <tt>org.zkoss.zk.ui.Page</tt> interface.
| |
| − |
| |
| − | |-
| |
| − | | desktopScope
| |
| − | | <tt>java.util.Map</tt>
| |
| − |
| |
| − | |A map of attributes defined in the desktop. It is the same as the <tt>getAttributes</tt> method in the <tt>org.zkoss.zk.ui.Desktop</tt> interface.
| |
| − |
| |
| − | |-
| |
| − | | sessionScope
| |
| − | | <tt>java.util.Map</tt>
| |
| − |
| |
| − | |A map of attributes defined in the session. It is the same as the <tt>getAttributes</tt> method in the <tt>org.zkoss.zk.ui.Session</tt> interface.
| |
| − |
| |
| − | |-
| |
| − | | applicationScope
| |
| − | | <tt>java.util.Map</tt>
| |
| − |
| |
| − | |A map of attributes defined in the web application. It is the same as the <tt>getAttributes</tt> method in the <tt>org.zkoss.zk.ui.WebApp</tt> interface.
| |
| − |
| |
| − | |-
| |
| − | | requestScope
| |
| − | | <tt>java.util.Map</tt>
| |
| − |
| |
| − | |A map of attributes defined in the request. It is the same as the <tt>getAttributes</tt> method in the <tt>org.zkoss.zk.ui.Execution</tt> interface.
| |
| − |
| |
| − | |-
| |
| − | | param
| |
| − | | <tt>java.util.Map</tt>
| |
| − |
| |
| − | |A map of attributes passed by the query string. Please refer to section [[Work_with_HTML_Tags#Pass_Values_to_the_Included_Page|Pass Values to the Included Page]] for example.
| |
| − |
| |
| − | |-
| |
| − | | arg
| |
| − | | <tt>java.util.Map</tt>
| |
| − |
| |
| − | |The <tt>arg</tt> argument passed to the <tt>createComponents</tt> method in the <tt>org.zkoss.zk.ui.Executions</tt> class. It is never <tt>null</tt>.
| |
| − |
| |
| − | It is the same as <tt>self.desktop.execution.arg</tt>.
| |
| − |
| |
| − | Notice that <tt>arg</tt> is available only when creating the components for the included page (the first argument of <tt>createComponents</tt>). On the other hand, all events, including <tt>onCreate</tt>, are processed later. Thus, if you want to access <tt>arg</tt> in the <tt>onCreate</tt>'s listener, use the <tt>getArg</tt> method of the <tt>org.zkoss.zk.ui.event.CreateEvent</tt> class.
| |
| − |
| |
| − |
| |
| − |
| |
| − | |-
| |
| − | | each
| |
| − | | <tt>java.lang.Object</tt>
| |
| − |
| |
| − | |The current item of the collection being iterated, when ZK evaluates an iterative element. An iterative element is an element with the forEach attribute.
| |
| − |
| |
| − | |-
| |
| − | | forEachStatus
| |
| − | | [http://www.zkoss.org/javadoc/3.5.1/zk/org/zkoss/zk/ui/util/foreachstatus.html <tt>org.zkoss.zk.ui.util.ForEachStatus</tt>]
| |
| − |
| |
| − | |The status of an iteration. ZK exposes the information relative to the iteration taking place when evaluating the iterative element.
| |
| − |
| |
| − | |-
| |
| − | | event
| |
| − | | [http://www.zkoss.org/javadoc/3.5.1/zk/org/zkoss/zk/ui/event/event.html <tt>org.zkoss.zk.ui.event.Event</tt>] or derived
| |
| − |
| |
| − | |The current event. Available for the event listener only.
| |
| − |
| |
| − | |}
| |
| − |
| |
| − |
| |
| − | Implicit objects provides many useful methods for web application. You can click the hyperlink to see the java doc of each implicit object.
| |
| − |
| |
| − | == Information about Request and Execution ==
| |
| − | An execution of a client request (e.g., ServletRequest). When a request sent from a client, the server constructs a Execution object to hold execution relevant info, and then serves the request through this execution.
| |
| − |
| |
| − | A client request, e.g., HttpServletRequest, might consist of multiple ZK request (AuRequest). However, these ZK requests must target the same desktop of pages (Page).
| |
| − |
| |
| − | The <tt>org.zkoss.zk.ui.Execution</tt> interface provides information about the current execution, such as the request parameters. To get the current execution, you could simply use the <tt>getCurrent</tt> method in the <tt>org.zkoss.zk.ui.Executions</tt> class. It's a static class.
| |
| − |
| |
| − | The following example will show the server name.
| |
| − | <source lang="xml" >
| |
| − | <window>
| |
| − | <zscript>
| |
| − | String sn = Executions.getCurrent().getServerName();
| |
| − | </zscript>
| |
| − | The server is: ${sn}
| |
| − | </window>
| |
| − | </source>
| |
| − |
| |
| − | ==Life cycle of page, execution, desktop, session, application==
| |
| − |
| |
| − | From small scope to big:
| |
| − | *page
| |
| − | : A single page.
| |
| − | *execution<ref><tt>execution</tt> in ZK is a wrapper of <tt>request</tt> in JSP </ref>
| |
| − | : Processing a request from client side. It can cross pages.
| |
| − | *desktop
| |
| − | : All pages serving the same URL, for one browser tab.
| |
| − | *session
| |
| − | : From user visit the web to user leave or timeout. All following pages are related to same session.
| |
| − | *application
| |
| − | : From the application service start to stop. It is cross session, cross users.
| |
| − |
| |
| − | Note that, if you press "F5" to refresh the web page, it's a different desktop, but the same session.
| |
| − |
| |
| − | ==About xxxScope==
| |
| − | Each xxxScope is a map of attribute of certain component. You can use it as a temporary space to save and retrieve data. It's a mechanism to realize communication between pages, applications. You have to understand each component's life cycle, to decide which scope you should use. In most cases, you should use <tt>session</tt>.
| |
| − | <tt>setAttribute</tt>, and <tt>getAttribute</tt> are the api to set and get variable in certain xxxScope.
| |
| − |
| |
| − |
| |
| − | '''Note'''
| |
| − | <references/>
| |
| − |
| |
| − | ==See Also==
| |
| − | :For more information, please refer to [http://www.zkoss.org/doc/devref-single/index.html#id456270 developer's reference]. The concept of implicit object is much like [http://java.sun.com/j2ee/tutorial/1_3-fcs/doc/JSPIntro7.html#70899 JSP].
| |
| − | :[[Most_used_api_for_Implicit_Objects_and_Static_Classes | Most used api for Implicit Objects and Static Classes]] -- includes Executions, Path, Clients
| |
| − |
| |
| − | == Quiz ==
| |
| − |
| |
| − | 1.Find Out the api of implicit object, that can
| |
| − |
| |
| − | *Creates components from the specified page definition
| |
| − |
| |
| − | *Sets a bookmark to this desktop.
| |
| − |
| |
| − | *Returns the Internet Protocol (IP) address of the interface on which the first request was received (and creates this session).
| |
| − |
| |
| − | 2.It's common to include another <tt>page</tt> inside current <tt>page</tt>, and it's a common need to pass variable between these 2 pages. Please refer to [[Work_with_HTML_Tags#The_include_Component | The include component]]. Use <tt>session.setAttribute</tt> and <tt>getAttribute</tt> to pass the value of <tt>passed</tt> between following 2 zul pages.
| |
| − |
| |
| − | helloworld.zul
| |
| − | <source lang="xml" >
| |
| − | <window>
| |
| − | <label id="passed" value="Hello, World!"/>
| |
| − | <include src="included.zul"/>
| |
| − | </window>
| |
| − | </source>
| |
| − |
| |
| − | And included.zul:
| |
| − | <source lang="xml" >
| |
| − | <window>
| |
| − | The value of passed is
| |
| − | </window>
| |
| − | </source>
| |
| | | | |
| | {{ ZKDevelopersGuidePageFooter}} | | {{ ZKDevelopersGuidePageFooter}} |
This documentation is for an older version of ZK. For the latest one, please click here.