To configure the DelegatingRequestProcessor in your struts-config.xml file, override the "processorClass" property in the <controller> element. These lines follow the <action-mapping> element.

<controller>
  <set-property property="processorClass"
      value="org.springframework.web.struts.DelegatingRequestProcessor"/>
</controller>

After adding this setting, your Action will automatically be looked up in Spring's context file, no matter what the type. In fact, you don't even need to specify a type. Both of the following snippets will work:

<action path="/user" type="com.whatever.struts.UserAction"/>		
	<action path="/user"/>

If you're using Struts' modules feature, your bean names must contain the module prefix. For example, an action defined as <action path="/user"/> with module prefix "admin" requires a bean name with <bean name="/admin/user"/>.

NOTE: If you're using Tiles in your Struts application, you must configure your <controller> with the DelegatingTilesRequestProcessor.

If you have a custom RequestProcessor and can't use the DelegatingTilesRequestProcessor, you can use the DelegatingActionProxy as the type in your action-mapping.

<action path="/user" type="org.springframework.web.struts.DelegatingActionProxy"
    name="userForm" scope="request" validate="false" parameter="method">
  <forward name="list" path="/userList.jsp"/>
  <forward name="edit" path="/userForm.jsp"/>
</action>

The bean definition in action-servlet.xml remains the same, whether you use a custom RequestProcessor or the DelegatingActionProxy.

If you define your Action in a context file, the full feature set of Spring's bean container will be available for it: dependency injection as well as the option to instantiate a new Action instance for each request. To activate the latter, add singleton="false" to your Action's bean definition.

<bean name="/user" singleton="false" autowire="byName"
    class="org.example.web.UserAction"/>

Assume we have the following simple Application Context definition, in xml form:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" 
        "http://www.springframework.org/dtd/spring-beans.dtd">
 
<beans>
 
    <!-- ========================= GENERAL DEFINITIONS ========================= -->
 
    <!-- ========================= PERSISTENCE DEFINITIONS ========================= -->
 
    <!-- the DataSource -->
    <bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
        <property name="jndiName"><value>java:DefaultDS</value></property>
        <property name="resourceRef"><value>false</value></property>
    </bean>
 
    <!-- define a Hibernate Session factory via a Spring LocalSessionFactoryBean -->
    <bean id="hibSessionFactory" 
        class="org.springframework.orm.hibernate.LocalSessionFactoryBean">
        <property name="dataSource"><ref bean="dataSource"/></property>
    </bean>
 
    <!--
     - Defines a transaction manager for usage in business or data access objects.
     - No special treatment by the context, just a bean instance available as reference
     - for business objects that want to handle transactions, e.g. via TransactionTemplate.
     -->
    <bean id="transactionManager" 
        class="org.springframework.transaction.jta.JtaTransactionManager">
    </bean>
 
    <bean id="mapper" 
        class="com.whatever.dataaccess.mapper.hibernate.MapperImpl">
        <property name="sessionFactory"><ref bean="hibSessionFactory"/></property>
    </bean>
   
    <!-- ========================= BUSINESS DEFINITIONS ========================= -->
 
    <!-- AuthenticationService, including tx interceptor -->
    <bean id="authenticationServiceTarget"
        class="com.whatever.services.service.user.AuthenticationServiceImpl">
        <property name="mapper"><ref bean="mapper"/></property>
    </bean>
    <bean id="authenticationService" 
        class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">
        <property name="transactionManager"><ref bean="transactionManager"/></property>
        <property name="target"><ref bean="authenticationServiceTarget"/></property>
        <property name="proxyInterfacesOnly"><value>true</value></property>
        <property name="transactionAttributes">
            <props>
                <prop key="*">PROPAGATION_REQUIRED</prop>
            </props>
        </property>
    </bean>  
 
    <!-- UserService, including tx interceptor -->
    <bean id="userServiceTarget"
        class="com.whatever.services.service.user.UserServiceImpl">
        <property name="mapper"><ref bean="mapper"/></property>
    </bean>
    <bean id="userService" 
        class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">
        <property name="transactionManager"><ref bean="transactionManager"/></property>
        <property name="target"><ref bean="userServiceTarget"/></property>
        <property name="proxyInterfacesOnly"><value>true</value></property>
        <property name="transactionAttributes">
            <props>
                <prop key="*">PROPAGATION_REQUIRED</prop>
            </props>
        </property>
    </bean>  
 
 </beans>

Inside the Tapestry application, we need to load this application context, and allow Tapestry pages to get the authenticationService and userService beans, which implement the AuthenticationService and UserService interfaces, respectively.

At this point, the application context is available to a web application by calling Spring's static utility function WebApplicationContextUtils.getApplicationContext(servletContext), where servletContext is the standard ServletContext from the J2EE Servlet specification. As such, one simple mechanism for a page to get an instance of the UserService, for example, would be with code such as:

    WebApplicationContext appContext = WebApplicationContextUtils.getApplicationContext(
        getRequestCycle().getRequestContext().getServlet().getServletContext());
    UserService userService = (UserService) appContext.getBean("userService");
    ... some code which uses UserService

This mechanism does work. It can be made a lot less verbose by encapsulating most of the functionality in a method in the base class for the page or component. However, in some respects it goes against the Inversion of Control approach which Spring encourages, which is being used in other layers of this app, in that ideally you would like the page to not have to ask the context for a specific bean by name, and in fact, the page would ideally not know about the context at all.

Luckily, there is a mechanism to allow this. We rely upon the fact that Tapestry already has a mechanism to declaratively add properties to a page, and it is in fact the preferred approach to manage all properties on a page in this declarative fashion, so that Tapestry can properly manage their lifecycle as part of the page and component lifecycle.

First we need to make the ApplicationContext available to the Tapestry page or Component without having to have the ServletContext; this is because at the stage in the page's/component's lifecycle when we need to access the ApplicationContext, the ServletContext won't be easily available to the page, so we can't use WebApplicationContextUtils.getApplicationContext(servletContext) directly. One way is by defining a custom version of the Tapestry IEngine which exposes this for us:

package com.whatever.web.xportal;
...
import ...
...
public class MyEngine extends org.apache.tapestry.engine.BaseEngine {
 
    public static final String APPLICATION_CONTEXT_KEY = "appContext";
 
    /**
     * @see org.apache.tapestry.engine.AbstractEngine#setupForRequest(org.apache.tapestry.request.RequestContext)
     */
    protected void setupForRequest(RequestContext context) {
        super.setupForRequest(context);
     
        // insert ApplicationContext in global, if not there
        Map global = (Map) getGlobal();
        ApplicationContext ac = (ApplicationContext) global.get(APPLICATION_CONTEXT_KEY);
        if (ac == null) {
            ac = WebApplicationContextUtils.getWebApplicationContext(
                context.getServlet().getServletContext()
            );
            global.put(APPLICATION_CONTEXT_KEY, ac);
        }
    }
}

This engine class places the Spring Application Context as an attribute called "appContext" in this Tapestry app's 'Global' object. Make sure to register the fact that this special IEngine instance should be used for this Tapestry application, with an entry in the Tapestry application definition file. For example:

file: xportal.application:
 
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE application PUBLIC 
    "-//Apache Software Foundation//Tapestry Specification 3.0//EN" 
    "http://jakarta.apache.org/tapestry/dtd/Tapestry_3_0.dtd">
<application
    name="Whatever xPortal"
    engine-class="com.whatever.web.xportal.MyEngine">
</application>

Now in our page or component definition file (*.page or *.jwc), we simply add property-specification elements to grab the beans we need out of the ApplicationContext, and create page or component properties for them. For example:

    <property-specification name="userService"
                            type="com.whatever.services.service.user.UserService">
        global.appContext.getBean("userService")
    </property-specification>
    <property-specification name="authenticationService"
                            type="com.whatever.services.service.user.AuthenticationService">
        global.appContext.getBean("authenticationService")
    </property-specification>

The OGNL expression inside the property-specification specifies the initial value for the property, as a bean obtained from the context. The entire page definition might look like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE page-specification PUBLIC 
    "-//Apache Software Foundation//Tapestry Specification 3.0//EN" 
    "http://jakarta.apache.org/tapestry/dtd/Tapestry_3_0.dtd">
     
<page-specification class="com.whatever.web.xportal.pages.Login">
 
    <property-specification name="username" type="java.lang.String"/>
    <property-specification name="password" type="java.lang.String"/>
    <property-specification name="error" type="java.lang.String"/>
    <property-specification name="callback" type="org.apache.tapestry.callback.ICallback" persistent="yes"/>
    <property-specification name="userService"
                            type="com.whatever.services.service.user.UserService">
        global.appContext.getBean("userService")
    </property-specification>
    <property-specification name="authenticationService"
                            type="com.whatever.services.service.user.AuthenticationService">
        global.appContext.getBean("authenticationService")
    </property-specification>
   
    <bean name="delegate" class="com.whatever.web.xportal.PortalValidationDelegate"/>
 
    <bean name="validator" class="org.apache.tapestry.valid.StringValidator" lifecycle="page">
        <set-property name="required" expression="true"/>
        <set-property name="clientScriptingEnabled" expression="true"/>
    </bean>
 
    <component id="inputUsername" type="ValidField">
        <static-binding name="displayName" value="Username"/>
        <binding name="value" expression="username"/>
        <binding name="validator" expression="beans.validator"/>
    </component>
   
    <component id="inputPassword" type="ValidField">
        <binding name="value" expression="password"/>
       <binding name="validator" expression="beans.validator"/>
       <static-binding name="displayName" value="Password"/>
       <binding name="hidden" expression="true"/>
    </component>
 
</page-specification>

Now in the Java class definition for the page or component itself, all we need to do is add an abstract getter method for the properties we have defined, to access them. When the page or component is actually loaded by Tapestry, it performs runtime code instrumentation on the classfile to add the properties which have been defined, and hook up the abstract getter methods to the newly created fields. For example:

    // our UserService implementation; will come from page definition
    public abstract UserService getUserService();
    // our AuthenticationService implementation; will come from page definition
    public abstract AuthenticationService getAuthenticationService();

For completeness, the entire Java class, for a login page in this example, might look like this:

package com.whatever.web.xportal.pages;
 
/**
 *  Allows the user to login, by providing username and password.
 *  After successfully logging in, a cookie is placed on the client browser
 *  that provides the default username for future logins (the cookie
 *  persists for a week).
 */
public abstract class Login extends BasePage implements ErrorProperty, PageRenderListener {
 
    /** the key under which the authenticated user object is stored in the visit as */
    public static final String USER_KEY = "user";
   
    /**
     * The name of a cookie to store on the user's machine that will identify
     * them next time they log in.
     **/
    private static final String COOKIE_NAME = Login.class.getName() + ".username";  
    private final static int ONE_WEEK = 7 * 24 * 60 * 60;
 
    // --- attributes
 
    public abstract String getUsername();
    public abstract void setUsername(String username);
 
    public abstract String getPassword();
    public abstract void setPassword(String password);
 
    public abstract ICallback getCallback();
    public abstract void setCallback(ICallback value);
    
    public abstract UserService getUserService();
 
    public abstract AuthenticationService getAuthenticationService();
 
    // --- methods
 
    protected IValidationDelegate getValidationDelegate() {
        return (IValidationDelegate) getBeans().getBean("delegate");
    }
 
    protected void setErrorField(String componentId, String message) {
        IFormComponent field = (IFormComponent) getComponent(componentId);
        IValidationDelegate delegate = getValidationDelegate();
        delegate.setFormComponent(field);
        delegate.record(new ValidatorException(message));
    }
 
    /**
     *  Attempts to login. 
     *
     *  <p>If the user name is not known, or the password is invalid, then an error
     *  message is displayed.
     *
     **/
    public void attemptLogin(IRequestCycle cycle) {
     
        String password = getPassword();
 
        // Do a little extra work to clear out the password.
 
        setPassword(null);
        IValidationDelegate delegate = getValidationDelegate();
 
        delegate.setFormComponent((IFormComponent) getComponent("inputPassword"));
        delegate.recordFieldInputValue(null);
 
        // An error, from a validation field, may already have occurred.
 
        if (delegate.getHasErrors())
            return;
 
        try {
            User user = getAuthenticationService().login(getUsername(), getPassword());
           loginUser(user, cycle);
        }
        catch (FailedLoginException ex) {
            this.setError("Login failed: " + ex.getMessage());
            return;
        }
    }
 
    /**
     *  Sets up the {@link User} as the logged in user, creates
     *  a cookie for their username (for subsequent logins),
     *  and redirects to the appropriate page, or
     *  a specified page).
     *
     **/
    public void loginUser(User user, IRequestCycle cycle) {
     
        String username = user.getUsername();
 
        // Get the visit object; this will likely force the
        // creation of the visit object and an HttpSession.
 
        Map visit = (Map) getVisit();
        visit.put(USER_KEY, user);
 
        // After logging in, go to the MyLibrary page, unless otherwise
        // specified.
 
        ICallback callback = getCallback();
 
        if (callback == null)
            cycle.activate("Home");
        else
            callback.performCallback(cycle);
 
        // I've found that failing to set a maximum age and a path means that
        // the browser (IE 5.0 anyway) quietly drops the cookie.
 
        IEngine engine = getEngine();
        Cookie cookie = new Cookie(COOKIE_NAME, username);
        cookie.setPath(engine.getServletPath());
        cookie.setMaxAge(ONE_WEEK);
 
        // Record the user's username in a cookie
 
        cycle.getRequestContext().addCookie(cookie);
 
        engine.forgetPage(getPageName());
    }
   
    public void pageBeginRender(PageEvent event) {
        if (getUsername() == null)
            setUsername(getRequestCycle().getRequestContext().getCookieValue(COOKIE_NAME));
    }
}