| <!DOCTYPE html> |
| <html lang="en"> |
| |
| <head> |
| <meta charset="UTF-8"> |
| <meta http-equiv="X-UA-Compatible" content="IE=edge"> |
| <meta name="viewport" content="width=device-width, initial-scale=1"> |
| <title>Apache TomEE</title> |
| <meta name="description" |
| content="Apache TomEE is a lightweight, yet powerful, JavaEE Application server with feature rich tooling." /> |
| <meta name="keywords" content="tomee,asf,apache,javaee,jee,shade,embedded,test,junit,applicationcomposer,maven,arquillian" /> |
| <meta name="author" content="Luka Cvetinovic for Codrops" /> |
| <link rel="icon" href="../../favicon.ico"> |
| <link rel="icon" type="image/png" href="../../favicon.png"> |
| <meta name="msapplication-TileColor" content="#80287a"> |
| <meta name="theme-color" content="#80287a"> |
| <link rel="stylesheet" type="text/css" href="../../css/normalize.css"> |
| <link rel="stylesheet" type="text/css" href="../../css/bootstrap.css"> |
| <link rel="stylesheet" type="text/css" href="../../css/owl.css"> |
| <link rel="stylesheet" type="text/css" href="../../css/animate.css"> |
| <link rel="stylesheet" type="text/css" href="../../fonts/font-awesome-4.1.0/css/font-awesome.min.css"> |
| <link rel="stylesheet" type="text/css" href="../../fonts/eleganticons/et-icons.css"> |
| <link rel="stylesheet" type="text/css" href="../../css/jqtree.css"> |
| <link rel="stylesheet" type="text/css" href="../../css/idea.css"> |
| <link rel="stylesheet" type="text/css" href="../../css/cardio.css"> |
| |
| <script type="text/javascript"> |
| |
| var _gaq = _gaq || []; |
| _gaq.push(['_setAccount', 'UA-2717626-1']); |
| _gaq.push(['_setDomainName', 'apache.org']); |
| _gaq.push(['_trackPageview']); |
| |
| (function() { |
| var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; |
| ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; |
| var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); |
| })(); |
| |
| </script> |
| </head> |
| |
| <body> |
| <div class="preloader"> |
| <img src="../../img/loader.gif" alt="Preloader image"> |
| </div> |
| <nav class="navbar"> |
| <div class="container"> |
| <div class="row"> <div class="col-md-12"> |
| |
| <!-- Brand and toggle get grouped for better mobile display --> |
| <div class="navbar-header"> |
| <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1"> |
| <span class="sr-only">Toggle navigation</span> |
| <span class="icon-bar"></span> |
| <span class="icon-bar"></span> |
| <span class="icon-bar"></span> |
| </button> |
| <a class="navbar-brand" href="/"> |
| <span> |
| |
| |
| <img src="../../img/logo-active.png"> |
| |
| |
| </span> |
| Apache TomEE |
| </a> |
| </div> |
| <!-- Collect the nav links, forms, and other content for toggling --> |
| <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1"> |
| <ul class="nav navbar-nav navbar-right main-nav"> |
| <li><a href="../../docs.html">Documentation</a></li> |
| <li><a href="../../community/index.html">Community</a></li> |
| <li><a href="../../security/security.html">Security</a></li> |
| <li><a href="../../download-ng.html">Downloads</a></li> |
| </ul> |
| </div> |
| <!-- /.navbar-collapse --> |
| </div></div> |
| </div> |
| <!-- /.container-fluid --> |
| </nav> |
| |
| |
| <div id="main-block" class="container main-block"> |
| <div class="row title"> |
| <div class="col-md-12"> |
| <div class='page-header'> |
| |
| <h1>Understanding Callbacks</h1> |
| </div> |
| </div> |
| </div> |
| <div class="row"> |
| |
| <div class="col-md-12"> |
| <div class="paragraph"> |
| <p>The rules here are pretty hard to follow without |
| examples.</p> |
| </div> |
| <div class="paragraph"> |
| <p>When they say one AroundInvoke per class they mean that in the most |
| literal sense as in one individual java class definition, not including |
| it’s parent class or classes, may exactly one AroundInvoke method. The |
| bean or interceptor class may have an AroundInvoke method, its parent |
| class may have an AroundInvoke method, the parent’s parent class may |
| have an AroundInvoke method and so on.</p> |
| </div> |
| <div class="paragraph"> |
| <p>So the following is legal.</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="highlight"><code class="language-java" data-lang="java">public class Plant { |
| @AroundInvoke |
| public Object a(InvocationContext ctx) throws Exception { |
| return ctx.proceed(); |
| } |
| } |
| |
| public class Fruit extends Plant { |
| @AroundInvoke |
| public Object b(InvocationContext ctx) throws Exception { |
| return ctx.proceed(); |
| } |
| } |
| |
| @Stateless |
| public class Apple extends Fruit implements AppleLocal { |
| @AroundInvoke |
| public Object c(InvocationContext ctx) throws Exception { |
| return ctx.proceed(); |
| } |
| |
| public String grow(){ |
| return "ready to pick"; |
| } |
| } |
| |
| public interface AppleLocal { |
| public String grow(); |
| }</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>The result is that when the "grow" method on AppleLocal (and |
| consequently on Apple) is invoked, the container will first invoke the |
| following AroundInvoke methods in this order; a, b, c.</p> |
| </div> |
| <div class="paragraph"> |
| <p>What the ejb spec doesn’t do such a good job at stating is that there |
| are ways to effectively shut off the callbacks, including AroundInvoke, |
| of a parent class by simply overriding the method. We can shut off the |
| "a" around invoke with a slightly different version of Apple as follows:</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="highlight"><code class="language-java" data-lang="java">@Stateless |
| public class Apple extends Fruit implements AppleLocal { |
| |
| // This will now never be called. |
| public Object a(InvocationContext ctx) throws Exception { |
| return null; |
| } |
| |
| @AroundInvoke |
| public Object c(InvocationContext ctx) throws Exception { |
| return ctx.proceed(); |
| } |
| |
| public String grow(){ |
| return "ready to pick"; |
| } |
| }</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>The result of this is that when the "grow" method on AppleLocal is |
| invoked, the container will first invoke the AroundInvoke methods "b" |
| then "c" skipping "a" completely.</p> |
| </div> |
| <div class="paragraph"> |
| <p>When they say that an AroundInvoke method cannot be a business method, |
| they mean that they cannot be exposed to clients through a local or |
| remote interface. The following would be illegal.</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="highlight"><code class="language-java" data-lang="java">public interface AppleLocal { |
| public String grow(); |
| |
| // This is an AroundInvoke method in the bean class, not a legal business method! |
| public Object c(InvocationContext ctx) throws Exception; |
| }</code></pre> |
| </div> |
| </div> |
| </div> |
| |
| </div> |
| </div> |
| <footer> |
| <div class="container"> |
| <div class="row"> |
| <div class="col-sm-6 text-center-mobile"> |
| <h3 class="white">Be simple. Be certified. Be Tomcat.</h3> |
| <h5 class="light regular light-white">"A good application in a good server"</h5> |
| <ul class="social-footer"> |
| <li><a href="https://www.facebook.com/ApacheTomEE/"><i class="fa fa-facebook"></i></a></li> |
| <li><a href="https://twitter.com/apachetomee"><i class="fa fa-twitter"></i></a></li> |
| <li><a href="https://plus.google.com/communities/105208241852045684449"><i class="fa fa-google-plus"></i></a></li> |
| </ul> |
| </div> |
| <div class="col-sm-6 text-center-mobile"> |
| <div class="row opening-hours"> |
| <div class="col-sm-3 text-center-mobile"> |
| <h5><a href="../../latest/docs/documentation.html" class="white">Documentation</a></h5> |
| <ul class="list-unstyled"> |
| <li><a href="../../latest/docs/admin/configuration/index.html" class="regular light-white">How to configure</a></li> |
| <li><a href="../../latest/docs/admin/file-layout.html" class="regular light-white">Dir. Structure</a></li> |
| <li><a href="../../latest/docs/developer/testing/index.html" class="regular light-white">Testing</a></li> |
| <li><a href="../../latest/docs/admin/cluster/index.html" class="regular light-white">Clustering</a></li> |
| </ul> |
| </div> |
| <div class="col-sm-3 text-center-mobile"> |
| <h5><a href="../../latest/examples/" class="white">Examples</a></h5> |
| <ul class="list-unstyled"> |
| <li><a href="../../latest/examples/simple-cdi-interceptor.html" class="regular light-white">CDI Interceptor</a></li> |
| <li><a href="../../latest/examples/rest-cdi.html" class="regular light-white">REST with CDI</a></li> |
| <li><a href="../../latest/examples/ejb-examples.html" class="regular light-white">EJB</a></li> |
| <li><a href="../../latest/examples/jsf-managedBean-and-ejb.html" class="regular light-white">JSF</a></li> |
| </ul> |
| </div> |
| <div class="col-sm-3 text-center-mobile"> |
| <h5><a href="../../community/index.html" class="white">Community</a></h5> |
| <ul class="list-unstyled"> |
| <li><a href="../../community/contributors.html" class="regular light-white">Contributors</a></li> |
| <li><a href="../../community/social.html" class="regular light-white">Social</a></li> |
| <li><a href="../../community/sources.html" class="regular light-white">Sources</a></li> |
| </ul> |
| </div> |
| <div class="col-sm-3 text-center-mobile"> |
| <h5><a href="../../security/index.html" class="white">Security</a></h5> |
| <ul class="list-unstyled"> |
| <li><a href="http://apache.org/security" target="_blank" class="regular light-white">Apache Security</a></li> |
| <li><a href="http://apache.org/security/projects.html" target="_blank" class="regular light-white">Security Projects</a></li> |
| <li><a href="http://cve.mitre.org" target="_blank" class="regular light-white">CVE</a></li> |
| </ul> |
| </div> |
| </div> |
| </div> |
| </div> |
| <div class="row bottom-footer text-center-mobile"> |
| <div class="col-sm-12 light-white"> |
| <p>Copyright © 1999-2016 The Apache Software Foundation, Licensed under the Apache License, Version 2.0. Apache TomEE, TomEE, Apache, the Apache feather logo, and the Apache TomEE project logo are trademarks of The Apache Software Foundation. All other marks mentioned may be trademarks or registered trademarks of their respective owners.</p> |
| </div> |
| </div> |
| </div> |
| </footer> |
| <!-- Holder for mobile navigation --> |
| <div class="mobile-nav"> |
| <ul> |
| <li><a hef="../../latest/docs/admin/index.html">Administrators</a> |
| <li><a hef="../../latest/docs/developer/index.html">Developers</a> |
| <li><a hef="../../latest/docs/advanced/index.html">Advanced</a> |
| <li><a hef="../../community/index.html">Community</a> |
| </ul> |
| <a href="#" class="close-link"><i class="arrow_up"></i></a> |
| </div> |
| <!-- Scripts --> |
| <script src="../../js/jquery-1.11.1.min.js"></script> |
| <script src="../../js/owl.carousel.min.js"></script> |
| <script src="../../js/bootstrap.min.js"></script> |
| <script src="../../js/wow.min.js"></script> |
| <script src="../../js/typewriter.js"></script> |
| <script src="../../js/jquery.onepagenav.js"></script> |
| <script src="../../js/tree.jquery.js"></script> |
| <script src="../../js/highlight.pack.js"></script> |
| <script src="../../js/main.js"></script> |
| </body> |
| |
| </html> |
| |
