Using Custom ZK Scopes For Spring Beans

Purpose

Use ZK custom scope for Spring beans.

Example

In this example, we will present user to enter a message which can be set into a Spring bean in a (custom) desktop scope. In addition to desktop scope, ZK Spring also supports webapp and execution scope (page scope, idspace scope have been deprecated). So that it can be shared by other pages, controllers, and view models attached to this same desktop.

Configuration

To enable the custom ZK scopes for your Spring Beans all you need is to add the <zksp:zk-config/> element (and namespace declaration) to your spring bean configuration file or use Java Config as shown below.

Java Config (since 4.0.0)

import org.zkoss.spring.config.ZkScopesConfigurer;

@Configuration
@Import(ZkScopesConfigurer.class)
public class YourApplicationConfiguration {
    ...
}

XML Config

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	   xmlns:zksp="http://www.zkoss.org/2008/zkspring/core"
	   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
            http://www.zkoss.org/2008/zkspring/core http://www.zkoss.org/2008/zkspring/core/zkspring-core-4.0.xsd">

	<!-- Enables ZK custom scopes for Spring Beans -->
	<zksp:zk-config/>
</beans>

Previous version 3.2 (or earlier)

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:zksp="http://www.zkoss.org/2008/zkspring/core"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
            http://www.zkoss.org/2008/zkspring/core http://www.zkoss.org/2008/zkspring/core/zkspring-core.xsd">

    <!-- Enables ZK custom scopes for Spring Beans -->
    <zksp:zk-config/>
...

Note that you need to declare ZK Spring Core namespace at the start of your configuration file.

ZUML

Let's take a look at the main page source

<?xml version="1.0" encoding="UTF-8"?>
<?variable-resolver class="org.zkoss.zkplus.spring.DelegatingVariableResolver"?>
<window title="Custom Scopes Example - Main Page" border="normal" height="100px" width="400px" 
    apply="${scopedCtrl}">
    <label value="Enter Message Text:"></label>
    <textbox id="name" />
    <button id="setMsgBtn" label="Set" />
    <button id="showMsgBtn" label="Show Message" />
    <button id="showWinBtn" label="Show Window" />
</window>

It has one textbox to enter a message. On clicking Set button we store this text in a SimpleMessageBean which is Autowired into scopesCtrl controller.

ATTENTION: As seen below the "scopedCtrl"-controller has the "prototype"-scope. This implies that a new instance is created every time you resolve it by name, even in the same page. However you can still reference the exact same instance using an implicit variable.

Java

The SimpleMessageBean is set to "desktop"-scope using the @Scope.

@Component("msgBean")
@Scope("desktop")
public class SimpleMessageBean {

    private String msg;
    
    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }
}

Being a "prototype"-scoped bean the controller can use @Autowired to get the SimpleMessageBean injected.

@Component("scopedCtrl")
@Scope("desktop")
public class ScopedController extends SelectorComposer {

    @Autowired
    private SimpleMessageBean msgBean; //wire spring bean

    @Wired
    private Textbox name; //wire ZK component

    @Listen("onClick = #setMsgBtn")
    public void setMessage(Event evt) {
        msgBean.setMsg(name.getValue());
    }
    
    @Listen("onClick = #showMsgBtn")
    public void showMessage(Event evt) throws InterruptedException {
        Messagebox.show(msgBean.getMsg());
    }

    @Listen("onClick = #showWinBtn")
    public void showMessage(Event evt) throws InterruptedException {
        Window win = (Window) Executions.getCurrent().createComponents("customScopesWindow.zul", null, null);
        win.doHighlighted();
    }
}

The onClick listener of the "Show Window"-button (above line 21-25), append "customScopesWindow.zul" (code below) to the current desktop.

<?xml version="1.0" encoding="UTF-8"?>
<?variable-resolver class="org.zkoss.zkplus.spring.DelegatingVariableResolver"?>
<window title="Custom Scopes Example - Window Page" border="normal" height="100px"
    width="400px" closable="true">
    <label value="Message Text:"></label>
    <textbox id="name" value="${msgBean.msg}"/>
</window>

Since it is attached to the same desktop we have access SimpleMessageBean instance stored in the desktop scope. We use our standard approach to use DelegatingVariableResolver to access such bean and assign its value to a textbox.