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 are using Tiles in your Struts application, you must configure your <controller> with the DelegatingTilesRequestProcessor instead.

If you have a custom RequestProcessor and can't use the DelegatingRequestProcessor or DelegatingTilesRequestProcessor approaches, 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 scope="prototype" to your Action's bean definition.

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

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 (in order to be able to access the properties).

// 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 the sake of 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 the cookie that identifies a user **/
    private static final String COOKIE_NAME = Login.class.getName() + ".username";
    private final static int ONE_WEEK = 7 * 24 * 60 * 60;

    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();

    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);
        }

        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));
        }
    }
}

Effecting the dependency injection of Spring-managed beans into Tapestry pages in Tapestry version 4.x is so much simpler. All that is needed is a single add-on library, and some (small) amount of (essentially boilerplate) configuration. Simply package and deploy this library with the (any of the) other libraries required by your web application (typically in WEB-INF/lib).

You will then need to create and expose the Spring container using the method detailed previously. You can then inject Spring-managed beans into Tapestry very easily; if we are using Java 5, consider the Login page from above: we simply need to annotate the appropriate getter methods in order to dependency inject the Spring-managed userService and authenticationService objects (lots of the class definition has been elided for clarity).

package com.whatever.web.xportal.pages;

public abstract class Login extends BasePage implements ErrorProperty, PageRenderListener {

    @InjectObject("spring:userService")
    public abstract UserService getUserService();

    @InjectObject("spring:authenticationService")
    public abstract AuthenticationService getAuthenticationService();

}

We are almost done. All that remains is the HiveMind configuration that exposes the Spring container stored in the ServletContext as a HiveMind service; for example:

<?xml version="1.0"?>
<module id="com.javaforge.tapestry.spring" version="0.1.1">

    <service-point id="SpringApplicationInitializer"
        interface="org.apache.tapestry.services.ApplicationInitializer"
        visibility="private">
        <invoke-factory>
            <construct class="com.javaforge.tapestry.spring.SpringApplicationInitializer">
                <set-object property="beanFactoryHolder"
                    value="service:hivemind.lib.DefaultSpringBeanFactoryHolder" />
            </construct>
        </invoke-factory>
    </service-point>

    <!-- Hook the Spring setup into the overall application initialization. -->
    <contribution
        configuration-id="tapestry.init.ApplicationInitializers">
        <command id="spring-context"
            object="service:SpringApplicationInitializer" />
    </contribution>

</module>

If you are using Java 5 (and thus have access to annotations), then that really is it.

If you are not using Java 5, then one obviously doesn't annotate one's Tapestry page classes with annotations; instead, one simply uses good old fashioned XML to declare the dependency injection; for example, inside the .page or .jwc file for the Login page (or component):

<inject property="userService" object="spring:userService"/>
<inject property="authenticationService" object="spring:authenticationService"/>

In this example, we've managed to allow service beans defined in a Spring container to be provided to the Tapestry page in a declarative fashion. The page class does not know where the service implementations are coming from, and in fact it is easy to slip in another implementation, for example, during testing. This inversion of control is one of the prime goals and benefits of the Spring Framework, and we have managed to extend it throughout the stack in this Tapestry application.