net.sf.click.extras.spring
Class SpringClickServlet

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          net.sf.click.ClickServlet
              net.sf.click.extras.spring.SpringClickServlet

All Implemented Interfaces:

Serializable, Servlet, ServletConfig

public class SpringClickServlet

extends ClickServlet

Provides an Spring framework integration SpringClickServlet.

This Spring integration servlet provides a number of integration options using Spring with Click pages. These options detailed below.

Spring instantiated Pages with Spring XML configuration

With this option Page classes are configured using Spring XML configuration. When the SpringClickServlet receives a page request converts the auto-mapped page class to the equivalent Spring bean name and gets a new instance from the Spring ApplicationContext.

 customer-list.htm  ->  com.mycorp.page.CustomerListPage  -> customerListPage
 HTML Request           Click Page Class                     Spring Bean Name 

If the page bean is not found in the ApplicationContxt then the full Page class name is used.

 customer-list.htm  ->  com.mycorp.page.CustomerListPage  -> com.mycorp.page.CustomerListPage
 HTML Request           Click Page Class                     Spring Bean Name 

This integration option requires you to configure all your Spring Page beans in your Spring XML configuration. While this may be quite laborious, it does support Spring 1.x and Java 1.4. An example page bean configuration is provided below:

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

    <bean id="customerListPage" class="com.mycorp.page.CustomerListPage" scope="prototype"/>

 </beans> 

Please Note ensure the page beans scope is set to "prototype" so a new \ page instance will be created with every HTTP request. Otherwise Spring will default to using singletons and your code will not be thread safe.

Click instantiated Pages with injected Spring beans and/or ApplicationContext

With this integration option Click will instantiate page instances and automatically inject any page properties which match Spring beans defined in the ApplicationContext.

An example Page class is provided below which has the customerService property automatically injected by the SpringClickServlet. Note the customerService property will need to be defined in a Spring XML configuration.

 package com.mycorp.page;

 import net.sf.click.Page;

 import com.mycorp.service.CustomerService;

 public class CustomerListPage extends Page {

     private CustomerService customerService;

     public void  setCustomerService(CustomerService customerService) {
         this.customerService = customerService;
     }

     ..
 } 

Page property bean name must match the bean name defined in the Spring XML configuration. Continuing our example the Spring XML configuration is provided below:

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

    <bean id="customerService" class="com.mycorp.service.CustomerService"/>

 </beans> 

This option will also automatically inject the ApplicationContext into new page instances which implement the ApplicationContextAware interface. Using the applicationContext you can lookup Spring beans manually in your pages. For example:

 public class CustomerListPage extends Page implements ApplicationContextAware {

     protected ApplicationContext applicationContext;

     public void setApplicationContext(ApplicationContext applicationContext)  {
         this.applicationContext = applicationContext;
     }

     public CustomerService getCustomerService() {
         return (CustomerService) applicationContext.getBean("customerService");
     }
 } 

This last strategy is probably the least convenient integration option.

Servlet Configuration

The SpringClickServlet can obtain the ApplicationContext either from WebApplicationContextUtils which is configured with a ContextLoaderListener. For example:

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

    <listener>
       <listener-class>
          org.springframework.web.context.ContextLoaderListener
       </listener-class>
    </listener>

    <servlet>
       <servlet-name>SpringClickServlet</servlet-name>
       <servlet-class>net.sf.click.extras.spring.SpringClickServlet</servlet-class>
       <load-on-startup>0</load-on-startup>
    </servlet>

    ..

 </web-app> 

Alternatively you can specify the path to the ApplicationContext as a servlet init parameter. For example:

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

    <servlet>
       <servlet-name>SpringClickServlet</servlet-name>
       <servlet-class>net.sf.click.extras.spring.SpringClickServlet</servlet-class>
       <init-param>
         <param-name>spring-path</param-name>
         <param-value>/applicationContext.xml</param-value>
       </init-param>
       <load-on-startup>0</load-on-startup>
    </servlet>

    ..

 </web-app> 

To configure page Spring bean injection you need to configure the inject-page-beans servlet init parameter. For example:

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

    ..

    <servlet>
       <servlet-name>SpringClickServlet</servlet-name>
       <servlet-class>net.sf.click.extras.spring.SpringClickServlet</servlet-class>
       <init-param>
         <param-name>inject-page-beans</param-name>
         <param-value>true</param-value>
       </init-param>
       <load-on-startup>0</load-on-startup>
    </servlet>

    ..

 </web-app> 

Author:

Malcolm Edgar, Paul Rule, Phil Barnes

See Also:

Serialized Form

Field Summary

protected ApplicationContext	applicationContext Spring application context bean factory.
static String	INJECT_PAGE_BEANS The Servlet initialization parameter name for the option to have the SpringClickServlet inject Spring beans into page instances: "inject-page-beans".
protected Map	pageSetterBeansMap The list of page injectable Spring beans, keyed on page class name.
static String	SPRING_PATH The Servlet initialization parameter name for the path to the Spring XML appliation context definition file: "spring-path".

Fields inherited from class net.sf.click.ClickServlet

CLICK_FORWARD, CONFIG_SERVICE_CLASS, configService, FORWARD_PAGE, logger, typeConverter

Constructor Summary

SpringClickServlet()

Method Summary

protected void	activatePageInstance(Page page) This method associates the ApplicationContext with any ApplicationContextAware pages and supports the deserialized of stateful pages.
protected ApplicationContext	getApplicationContext() Return the configured Spring application context.
void	init() Initialize the SpringClickServlet and the Spring application context bean factory.
protected Page	newPageInstance(String path, Class pageClass, HttpServletRequest request) Create a new Spring Page bean if defined in the application context, or a new Page instance otherwise.
protected String	toBeanName(Class aClass) Return the Spring beanName for the given class.

Methods inherited from class net.sf.click.ClickServlet

createContext, createControlRegistry, createErrorPage, createPage, createPage, createPage, createPageImports, createTemplateModel, destroy, doGet, doPost, getConfigService, getTypeConverter, handleException, handleRequest, initPage, processPage, processPageOnDestroy, processPageRequestParams, renderJSP, renderTemplate, setPageResponseHeaders, setRequestAttributes

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doHead, doOptions, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INJECT_PAGE_BEANS

public static final String INJECT_PAGE_BEANS

The Servlet initialization parameter name for the option to have the SpringClickServlet inject Spring beans into page instances: "inject-page-beans".

See Also:

Constant Field Values

SPRING_PATH

public static final String SPRING_PATH

The Servlet initialization parameter name for the path to the Spring XML appliation context definition file: "spring-path".

See Also:

Constant Field Values

applicationContext

protected ApplicationContext applicationContext

Spring application context bean factory.

pageSetterBeansMap

protected Map pageSetterBeansMap

The list of page injectable Spring beans, keyed on page class name.

Constructor Detail

SpringClickServlet

public SpringClickServlet()

Method Detail

init

public void init()
          throws ServletException

Initialize the SpringClickServlet and the Spring application context bean factory. An Spring ClassPathXmlApplicationContext bean factory is used and initialize with the servlet init-param named "spring-path".

Throws:

ServletException - if the click app could not be initialized

See Also:

ClickServlet.init()

newPageInstance

protected Page newPageInstance(String path,
                               Class pageClass,
                               HttpServletRequest request)
                        throws Exception

Create a new Spring Page bean if defined in the application context, or a new Page instance otherwise.

If the "inject-paget-beans" option is enable this method will inject any Spring beans matching the Page's properties.

Parameters:

path - the request page path

pageClass - the page Class the request is mapped to

request - the page request

Returns:

a new Page object

Throws:

Exception - if an error occurs creating the Page

See Also:

ClickServlet.newPageInstance(String, Class, HttpServletRequest)

getApplicationContext

protected ApplicationContext getApplicationContext()

Return the configured Spring application context.

Returns:

the configured Spring application context.

activatePageInstance

protected void activatePageInstance(Page page)

This method associates the ApplicationContext with any ApplicationContextAware pages and supports the deserialized of stateful pages.

Parameters:

page - the page instance to activate

See Also:

ClickServlet.activatePageInstance(Page)

toBeanName

protected String toBeanName(Class aClass)

Return the Spring beanName for the given class.

Parameters:

aClass - the class to get the Spring bean name from

Returns:

the class bean name