{"id":132,"date":"2009-06-19T21:30:55","date_gmt":"2009-06-20T04:30:55","guid":{"rendered":"http:\/\/www.connorgarvey.com\/blog\/?p=132"},"modified":"2010-02-12T09:00:46","modified_gmt":"2010-02-12T16:00:46","slug":"using-guice-with-flex-remoting-for-blazeds","status":"publish","type":"post","link":"https:\/\/connorgarvey.com\/blog\/?p=132","title":{"rendered":"Using Guice with Flex remoting for BlazeDS"},"content":{"rendered":"

I just finished putting a server together that uses Google’s Guice<\/a> and Adobe’s BlazeDS<\/a>.\u00a0 Here’s how you can quickly get a project working using the same configuration.<\/p>\n

* Update:<\/em> A new post describes using Guice’s ServletModule to configure the MessageBrokerServlet<\/a>.<\/p>\n

Download the libraries<\/h3>\n

Download Guice<\/a> and BlazeDS<\/a>.\u00a0 Use the project configured in the BlazeDS war to get started.<\/p>\n

Create the Guice factory<\/h3>\n

Since BlazeDS provides the servlet, you won’t be able to configure your classes using Guice unless you have a Flex factory.\u00a0 This code will inject itself with Guice to get instances of Flex services.<\/p>\n

<\/a>Code block<\/a><\/td><\/a> <\/a> <\/a> <\/td><\/tr><\/table><\/div>
package<\/span> com.connorgarvey.guiceblazeds.servlet<\/span>;<\/span>\n \nimport<\/span> java.util.HashMap<\/span>;<\/span>\nimport<\/span> java.util.Map<\/span>;<\/span>\nimport<\/span> com.google.inject.Injector<\/span>;<\/span>\nimport<\/span> flex.messaging.FactoryInstance<\/span>;<\/span>\nimport<\/span> flex.messaging.FlexContext<\/span>;<\/span>\nimport<\/span> flex.messaging.FlexFactory<\/span>;<\/span>\nimport<\/span> flex.messaging.config.ConfigMap<\/span>;<\/span>\nimport<\/span> flex.messaging.services.ServiceException<\/span>;<\/span>\n \n\/**\n * <p>A Flex factory that retrieves instances of Flex services from Guice<\/p>\n * <p>This is based on a similar factory built for Spring by Jeff Vroom<\/p>\n * @author Connor Garvey\n * @created May 27, 2009 1:09:49 PM\n * @version 1.0.0\n * @since 1.0.0\n *\/<\/span>\npublic<\/span> class<\/span> GuiceFactory implements<\/span> FlexFactory {<\/span>\n  private<\/span> static<\/span> final<\/span> String<\/span><\/a> SOURCE =<\/span> "source"<\/span>;<\/span>\n \n  \/**\n   * @see flex.messaging.FlexFactory#createFactoryInstance(java.lang.String, flex.messaging.config.ConfigMap)\n   *\/<\/span>\n  public<\/span> FactoryInstance createFactoryInstance(<\/span>final<\/span> String<\/span><\/a> id, final<\/span> ConfigMap properties)<\/span> {<\/span>\n    final<\/span> GuiceFactoryInstance instance =<\/span> new<\/span> GuiceFactoryInstance(<\/span>this<\/span>, id, properties)<\/span>;<\/span>\n    instance.setSource<\/span>(<\/span>properties.getPropertyAsString<\/span>(<\/span>SOURCE, instance.getId<\/span>(<\/span>)<\/span>)<\/span>)<\/span>;<\/span>\n    return<\/span> instance;<\/span>\n  }<\/span>\n \n  \/**\n   * @see flex.messaging.FlexConfigurable#initialize(java.lang.String, flex.messaging.config.ConfigMap)\n   *\/<\/span>\n  public<\/span> void<\/span> initialize(<\/span>final<\/span> String<\/span><\/a> id, final<\/span> ConfigMap configMap)<\/span> {<\/span>\n  }<\/span>\n \n  \/**\n   * @see flex.messaging.FlexFactory#lookup(flex.messaging.FactoryInstance)\n   *\/<\/span>\n  public<\/span> Object<\/span><\/a> lookup(<\/span>final<\/span> FactoryInstance inst)<\/span> {<\/span>\n    return<\/span> inst.lookup<\/span>(<\/span>)<\/span>;<\/span>\n  }<\/span>\n \n  static<\/span> class<\/span> GuiceFactoryInstance extends<\/span> FactoryInstance {<\/span>\n    private<\/span> Map<<\/span>String, Class<?>><\/span> classes =<\/span> new<\/span> HashMap<<\/span>String, Class<?>><\/span>(<\/span>)<\/span>;<\/span>\n    GuiceFactoryInstance(<\/span>final<\/span> GuiceFactory factory, final<\/span> String<\/span><\/a> id, final<\/span> ConfigMap properties)<\/span> {<\/span>\n      super<\/span>(<\/span>factory, id, properties)<\/span>;<\/span>\n    }<\/span>\n \n    @Override\n    public<\/span> Object<\/span><\/a> lookup(<\/span>)<\/span> {<\/span>\n      final<\/span> Injector injector =<\/span> (<\/span>Injector)<\/span>FlexContext.getServletContext<\/span>(<\/span>)<\/span>.getAttribute<\/span>(<\/span>\n          GuiceServletContextListener.KEY<\/span>)<\/span>;<\/span>\n      injector.injectMembers<\/span>(<\/span>this<\/span>)<\/span>;<\/span>\n      String<\/span><\/a> className =<\/span> this<\/span>.getSource<\/span>(<\/span>)<\/span>;<\/span>\n      Class<?><\/span> clazz =<\/span> this<\/span>.classes<\/span>.get<\/span>(<\/span>className)<\/span>;<\/span>\n      if<\/span> (<\/span>clazz ==<\/span> null<\/span>)<\/span> {<\/span>\n        try<\/span> {<\/span>\n          clazz =<\/span> Class<\/span>.forName<\/span>(<\/span>this<\/span>.getSource<\/span>(<\/span>)<\/span>)<\/span>;<\/span>\n          this<\/span>.classes<\/span>.put<\/span>(<\/span>className, clazz)<\/span>;<\/span>\n        }<\/span>\n        catch<\/span> (<\/span>ClassNotFoundException<\/span><\/a> ex)<\/span> {<\/span>\n          ServiceException throwing =<\/span> new<\/span> ServiceException(<\/span>)<\/span>;<\/span>\n          throwing.setMessage<\/span>(<\/span>"Could not find remote service class '"<\/span> +<\/span> this<\/span>.getSource<\/span>(<\/span>)<\/span> +<\/span> "'"<\/span>)<\/span>;<\/span>\n          throwing.setRootCause<\/span>(<\/span>ex)<\/span>;<\/span>\n          throwing.setCode<\/span>(<\/span>"Server.Processing"<\/span>)<\/span>;<\/span>\n          throw<\/span> throwing;<\/span>\n        }<\/span>\n      }<\/span>\n      return<\/span> injector.getInstance<\/span>(<\/span>clazz)<\/span>;<\/span>\n    }<\/span>\n \n    @Override\n    public<\/span> String<\/span><\/a> toString(<\/span>)<\/span> {<\/span>\n      return<\/span> "Guice factory <id='"<\/span> +<\/span> this<\/span>.getId<\/span>(<\/span>)<\/span> +<\/span> "',source='"<\/span> +<\/span> this<\/span>.getSource<\/span>(<\/span>)<\/span> +<\/span>\n          "',scope='"<\/span> +<\/span> this<\/span>.getScope<\/span>(<\/span>)<\/span> +<\/span> "'>"<\/span>;<\/span>\n    }<\/span>\n  }<\/span>\n}<\/span><\/pre><\/div><\/div>\n
Create a context listener<\/h3>\n
The Guice servlet jar contains a ServletContextListener, but I haven’t taken the time to integrate it into this solution. \u00a0For simplicity, you can use this one, which works with the factory above.<\/p>\n
<\/a>Code block<\/a><\/td><\/a> <\/a> <\/a> <\/td><\/tr><\/table><\/div>
package<\/span> com.connorgarvey.guiceblazeds.servlet<\/span>;<\/span>\n \nimport<\/span> java.util.List<\/span>;<\/span>\nimport<\/span> javax.servlet.ServletContext<\/span>;<\/span>\nimport<\/span> javax.servlet.ServletContextEvent<\/span>;<\/span>\nimport<\/span> javax.servlet.ServletContextListener<\/span>;<\/span>\nimport<\/span> com.google.inject.Guice<\/span>;<\/span>\nimport<\/span> com.google.inject.Injector<\/span>;<\/span>\nimport<\/span> com.google.inject.Module<\/span>;<\/span>\n \n\/**\n * Prepares Guice on application startup\n * @author Connor Garvey\n * @created May 27, 2009 8:37:26 AM\n * @version 1.0.0\n * @since 1.0.0\n *\/<\/span>\npublic<\/span> abstract<\/span> class<\/span> GuiceServletContextListener implements<\/span> ServletContextListener {<\/span>\n  \/**\n   * The key of the servlet context attribute holding the injector\n   *\/<\/span>\n  public<\/span> static<\/span> final<\/span> String<\/span><\/a> KEY =<\/span> Injector.class<\/span>.getName<\/span>(<\/span>)<\/span>;<\/span>\n \n  \/**\n   * @see javax.servlet.ServletContextListener#contextDestroyed(javax.servlet.ServletContextEvent)\n   *\/<\/span>\n  public<\/span> void<\/span> contextDestroyed(<\/span>final<\/span> ServletContextEvent servletContextEvent)<\/span> {<\/span>\n    servletContextEvent.getServletContext<\/span>(<\/span>)<\/span>.removeAttribute<\/span>(<\/span>KEY)<\/span>;<\/span>\n  }<\/span>\n \n  \/**\n   * @see javax.servlet.ServletContextListener#contextInitialized(javax.servlet.ServletContextEvent)\n   *\/<\/span>\n  public<\/span> void<\/span> contextInitialized(<\/span>final<\/span> ServletContextEvent servletContextEvent)<\/span> {<\/span>\n    servletContextEvent.getServletContext<\/span>(<\/span>)<\/span>.setAttribute<\/span>(<\/span>KEY,\n        this<\/span>.getInjector<\/span>(<\/span>servletContextEvent.getServletContext<\/span>(<\/span>)<\/span>)<\/span>)<\/span>;<\/span>\n  }<\/span>\n \n  private<\/span> Injector getInjector(<\/span>final<\/span> ServletContext servletContext)<\/span> {<\/span>\n    return<\/span> Guice.createInjector<\/span>(<\/span>this<\/span>.getModules<\/span>(<\/span>)<\/span>)<\/span>;<\/span>\n  }<\/span>\n \n  \/**\n   * Gets the modules used by the application\n   * @return the modules\n   *\/<\/span>\n  protected<\/span> abstract<\/span> List<?<\/span> extends<\/span> Module><\/span> getModules(<\/span>)<\/span>;<\/span>\n}<\/span><\/pre><\/div><\/div>\n
Extend GuiceContextListener<\/h3>\n
Create a concret version of the class above. \u00a0It should return all modules needed for the application.<\/p>\n
Modify web.xml<\/h3>\n
Now, prepare web.xml with the normal BlazeDS settings plus some extras for Guice.<\/p>\n
<\/a>Code block<\/a><\/td><\/a> <\/a> <\/a> <\/td><\/tr><\/table><\/div>
<?xml<\/span> version<\/span>="1.0"<\/span> encoding<\/span>="UTF-8"<\/span>?><\/span><\/span>\n<!DOCTYPE web-app PUBLIC "-\/\/Sun Microsystems, Inc.\/\/DTD Web Application 2.3\/\/EN" "http:\/\/java.sun.com\/dtd\/web-app_2_3.dtd"><\/span>\n<web-app><\/span><\/span><\/span>\n  <display-name><\/span><\/span><\/span>Guice BlazeDS<\/display-name><\/span><\/span><\/span>\n  <description><\/span><\/span><\/span>Guice BlazeDS<\/description><\/span><\/span><\/span>\n  <listener><\/span><\/span><\/span>\n    <listener-class><\/span><\/span><\/span>flex.messaging.HttpFlexSession<\/listener-class><\/span><\/span><\/span>\n  <\/listener><\/span><\/span><\/span>\n  <listener><\/span><\/span><\/span>\n    <listener-class><\/span><\/span><\/span>com.connorgarvey.guiceblazeds.servlet.MyCustomGuiceServletContextListener<\/listener-class><\/span><\/span><\/span>\n  <\/listener><\/span><\/span><\/span>\n  <servlet><\/span><\/span><\/span>\n    <servlet-name><\/span><\/span><\/span>MessageBrokerServlet<\/servlet-name><\/span><\/span><\/span>\n    <display-name><\/span><\/span><\/span>MessageBrokerServlet<\/display-name><\/span><\/span><\/span>\n    <servlet-class><\/span><\/span><\/span>flex.messaging.MessageBrokerServlet<\/servlet-class><\/span><\/span><\/span>\n    <init-param><\/span><\/span><\/span>\n      <param-name><\/span><\/span><\/span>services.configuration.file<\/param-name><\/span><\/span><\/span>\n      <param-value><\/span><\/span><\/span>\/WEB-INF\/config\/flex\/services-config.xml<\/param-value><\/span><\/span><\/span>\n    <\/init-param><\/span><\/span><\/span>\n    <load-on-startup><\/span><\/span><\/span>1<\/load-on-startup><\/span><\/span><\/span>\n  <\/servlet><\/span><\/span><\/span>\n  <servlet-mapping><\/span><\/span><\/span>\n    <servlet-name><\/span><\/span><\/span>MessageBrokerServlet<\/servlet-name><\/span><\/span><\/span>\n    <url-pattern><\/span><\/span><\/span>\/messagebroker\/*<\/url-pattern><\/span><\/span><\/span>\n  <\/servlet-mapping><\/span><\/span><\/span>\n  <welcome-file-list><\/span><\/span><\/span>\n    <welcome-file><\/span><\/span><\/span>index.html<\/welcome-file><\/span><\/span><\/span>\n    <welcome-file><\/span><\/span><\/span>index.htm<\/welcome-file><\/span><\/span><\/span>\n  <\/welcome-file-list><\/span><\/span><\/span>\n<\/web-app><\/span><\/span><\/span><\/pre><\/div><\/div>\n
This way, BlazeDS will start at server startup, followed by Guice.<\/p>\n
Modify BlazeDS config<\/h3>\n
Open services-config.xml and add this at the top of the file. \u00a0Point it to the Guice factory.<\/p>\n
<\/a>Code block<\/a><\/td><\/a> <\/a> <\/a> <\/td><\/tr><\/table><\/div>
<?xml<\/span> version<\/span>="1.0"<\/span> encoding<\/span>="UTF-8"<\/span>?><\/span><\/span>\n<services-config><\/span><\/span><\/span>\n  <factories><\/span><\/span><\/span>\n    <factory<\/span> id<\/span>="guice"<\/span> class<\/span>="com.connorgarvey.guiceblazeds.servlet.GuiceFactory"<\/span> \/><\/span><\/span>\n  <\/factories><\/span><\/span><\/span><\/pre><\/div><\/div>\n
Set the factory of all remoting destinations<\/h3>\n
In remoting-config.xml, be sure to set the factory of all destinations to the name specified in services-config.xml above.<\/p>\n
<destination id=\"SomeService\">\r\n  <properties>\r\n    <factory>guice<\/factory>\r\n    <source>com.connorgarvey.guiceblazeds.service.flex.SomeFlexService<\/source>\r\n  <\/properties>\r\n<\/destination><\/pre>\n
How this all works<\/h3>\n
    \n
  1. When the server starts, BlazeDS and Guice are initialized by the servlet listeners.<\/li>\n
  2. When BlazeDS receives a request, to a service, it’ll see that it’s supposed to retrieve it from the “guice” factory.<\/li>\n
  3. The Guice factory will return an instance of the class specified in the source of the service configuration from Guice to BlazeDS for use in completing the request.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"
    I just finished putting a server together that uses Google’s Guice and Adobe’s BlazeDS.\u00a0 Here’s how you can quickly get a project working using the same configuration. * Update: A new post describes using Guice’s ServletModule to configure the MessageBrokerServlet. Download the libraries Download Guice and BlazeDS.\u00a0 Use the project configured in the BlazeDS war […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false},"version":2}},"categories":[26],"tags":[32,30,31,62,24,4,7,16],"class_list":["post-132","post","type-post","status-publish","format-standard","hentry","category-guice","tag-adobe","tag-blazeds","tag-google","tag-guice","tag-injection","tag-java","tag-redpoint","tag-source"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p1ql2n-28","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/connorgarvey.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/132","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/connorgarvey.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/connorgarvey.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/connorgarvey.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/connorgarvey.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=132"}],"version-history":[{"count":9,"href":"https:\/\/connorgarvey.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/132\/revisions"}],"predecessor-version":[{"id":165,"href":"https:\/\/connorgarvey.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/132\/revisions\/165"}],"wp:attachment":[{"href":"https:\/\/connorgarvey.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=132"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/connorgarvey.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=132"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/connorgarvey.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=132"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}