ZK Essentials/Chapter 9: Spring Integration

Overview

Spring Framework is a popular application development framework for enterprise Java. One key element is its infrastructural support: a light-weighted IoC (Inversion of Control) container that manages POJOs as Spring beans and their dependency relationship.

In this chapter, we won't create new example applications but will make previous examples integrated with Spring.

How to Integrate Spring Framework

The most common integration way is to let Spring manage an application's dependencies.

Configuration

Maven

In order to integrate Spring, we must add dependencies for Spring. The cglib is an optional dependency. We add it because our application uses proxy beans that requires it.

Extracted from pom.xml

	<properties>
		<zk.version>6.5.1</zk.version>
		<maven.build.timestamp.format>yyyy-MM-dd</maven.build.timestamp.format>
		<packname>-${project.version}-FL-${maven.build.timestamp}</packname>
		<spring.version>3.1.2.RELEASE</spring.version>
	</properties>
...
		<!-- Spring 3 dependencies -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-web</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<dependency>
			<groupId>cglib</groupId>
			<artifactId>cglib</artifactId>
			<version>2.2.2</version>
		</dependency>

Deployment Descriptor

The deployment descriptor (web.xml) also needs two more listeners.

Extracted from web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> 

	<description><![CDATA[ZK Tutorial]]></description>
	<display-name>ZK Tutorial</display-name>

	<!-- ZK configuration-->
	...
	
	<!-- Spring configuration -->
	<!-- Initialize spring context -->
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
	<!-- Enable webapp Scopes-->
	 <listener>
    	<listener-class>org.springframework.web.context.request.RequestContextListener</listener-class>
	</listener>
	
	<welcome-file-list>
		<welcome-file>index.zul</welcome-file>
	</welcome-file-list>
</web-app>

• Line 16: The ContextLoaderListener reads Spring configuration, and default location is WEB-INF/applicationContext.xml.
• Line 20: Use RequestContextListener to support web-scoped beans (request, session, global session).

Create Spring configuration file with default name (applicationContext.xml).

WEB-INF/applicationContext.xml

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="
        http://www.springframework.org/schema/beans     
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-3.0.xsd">
 
 	<context:component-scan base-package="org.zkoss.tutorial" />
 
</beans>

• Line 10: This configuration enables scanning classpath, automatically detecting classes, and registering bean definitions.

Define Spring Beans

@Service("authService")
@Scope(value="singleton",proxyMode=ScopedProxyMode.TARGET_CLASS)
public class AuthenticationServiceImpl implements AuthenticationService,Serializable{
...
}

reason for request scope ?

@Component("sidebarPageConfigPagebase")
@Scope(value="request",proxyMode=ScopedProxyMode.TARGET_CLASS)
public class SidebarPageConfigPagebaseImpl implements SidebarPageConfig{
...
}

Retrieve Spring Beans

@VariableResolver(DelegatingVariableResolver.class)
public class SidebarChapter4Controller extends SelectorComposer<Component>{

	private static final long serialVersionUID = 1L;
	
	//wire components
	@Wire
	Grid fnList;
	
	//wire service
	@WireVariable("sidebarPageConfigPagebase")
	SidebarPageConfig pageConfig;

	...
}

@VariableResolver(DelegatingVariableResolver.class)
public class ProfileViewModel implements Serializable{
	private static final long serialVersionUID = 1L;

	//wire services
	@WireVariable
	AuthenticationService authService;
	@WireVariable
	UserInfoService userInfoService;
	...
}