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  • How to deploy EJB on server?

    - by shekhar
    Hi, I am learning EJB3 from last few days. I have many questions regarding EJB, application servers and deployment of EJB. To start with, I have created one simple helloworld stateless session bean but I don't know how to deploy it on server. It has single bean class, bean interface and one servlet client. I have used eclipse to develop this project. None of the books that I read gives step by step details about how to put EJB on server and how to access those beans. I have JBoss 6 server and I also have JEE budle downloaded from sun website. Does this JEE bundle contains Glassfish server? or do I need to download it seperately? Can anyone please give me step by step details of how to put my bean and its client on server (JBoss or JEE)? and why do we need to include bean interface class in EJB client code? I mean either we need to keep client and bean in same package or if we keep them in seperate packages we need to import bean interfaces in client code. Am I right? Thanks and Regards, Chandrashekhar

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  • Communication between EJB3 Instances (JEE inter-bean communication) possible?

    - by Hank
    I'm designing a part of a JEE6 application, consisting of EJB3 beans. Part of the requirements are multiple parallel (say a few hundred) long running (over days) database hunts. Individual hunts have different search parameters (start time, end time, query filter). Parameters may get changed over time. Currently I'm thinking of the following: SearchController (Stateless Session Bean) formulates a set of search parameters, sends it off to a SearchListener via JMS SearchListener (Message Driven Bean) receives search parameters, instantiates a SearchWorker with the parameters SearchWorker (SLSB) hunts repeatedly through the database; when it finds something, the result is sent off via JMS, and the search continues; when the given 'end-time' has reached, it ends What I'm wondering now: Is there a problem, with EJB3 instances running for days? (Other than that I need to be able to deal with container restarts...) How do I know how many and which EJB instances of SearchWorker are currently running? Is it possible to communicate with them individually (similar to sending a System V signal to a unix process), e.g. to send new parameters, to end an instance, etc..

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  • JBoss: What does the warning EJBTHREE-1246 from the InterceptorRegistry mean?

    - by Simon Lehmann
    I am currently developing an EJB 3.0 based application on the JBoss AS 5.0.0.GA and just recently the following warning showed up in the server log: 09:50:19,735 WARN [InterceptorsFactory] EJBTHREE-1246: Do not use InterceptorsFactory with a ManagedObjectAdvisor, InterceptorRegistry should be used via the bean container 09:50:19,735 WARN [InterceptorsFactory] EJBTHREE-1246: Do not use InterceptorsFactory with a ManagedObjectAdvisor, InterceptorRegistry should be used via the bean container 09:50:19,735 WARN [InterceptorRegistry] applicable interceptors is non-existent for ... ... The warnings are generated as soon as an EJB (a stateless session bean) is injected into a backing bean of my JSF web-application. The beans do work without problems though, but I still would like to know where that warning comes from and what I can do to avoid it. I have already searched a bit around, but haven't found a good answer (some say, bean developers do not have to worry, but its a warning, so I'd like to have a better solution): http://www.jboss.com/index.html?module=bb&op=viewtopic&t=147292 http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4180366 http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4140136 JBoss JIRA Issue about the warning (Not that helpful in my opinion) So has anyone an explanation what causes the warning (in terms of a bean developer, not application server developer) and what to do to avoid it? Update: I've just upgraded JBoss to 5.0.1.GA (Download, Release-Notes) but unfortunatly the warning still appears.

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  • MVVM pattern: ViewModel updates after Model server roundtrip

    - by Pavel Savara
    I have stateless services and anemic domain objects on server side. Model between server and client is POCO DTO. The client should become MVVM. The model could be graph of about 100 instances of 20 different classes. The client editor contains diverse tab-pages all of them live-connected to model/viewmodel. My problem is how to propagate changes after server round-trip nice way. It's quite easy to propagate changes from ViewModel to DTO. For way back it would be possible to throw away old DTO and replace it whole with new one, but it will cause lot of redrawing for lists/DataTemplates. I could gather the server side changes and transmit them to client side. But the names of fields changed would be domain/DTO specific, not ViewModel specific. And the mapping seems nontrivial to me. If I should do it imperative way after round-trip, it would break SOC/modularity of viewModels. I'm thinking about some kind of mapping rule engine, something like automappper or emit mapper. But it solves just very plain use-cases. I don't see how it would map/propagate/convert adding items to list or removal. How to identify instances in collections so it could merge values to existing instances. As well it should propagate validation/error info. Maybe I should implement INotifyPropertyChanged on DTO and try to replay server side events on it ? And then bind ViewModel to it ? Would binding solve the problems with collection merges nice way ? Is EventAgregator from PRISM useful for that ? Is there any event record-replay component ? Is there better client side pattern for architecture with server side logic ?

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  • HTTP: can GET and POST requests from a same machine come from different IPs?

    - by NoozNooz42
    I'm pretty sure I remember reading --but cannot find back the links anymore-- about this: on some ISP (including at least one big ISP in the U.S.) it is possible to have a user's GET and POST request appearing to come from different IPs. (note that this is totally programming related, and I'll give an example below) I'm not talking about having your IP adress dynamically change between two requests. I'm talking about this: IP 1: 123.45.67.89 IP 2: 101.22.33.44 The same user makes a GET, then a POST, then a GET again, then a POST again and the servers see this: - GET from IP 1 - POST from IP 2 - GET from IP 1 - POST from IP 2 So altough it's the same user, the webserver sees different IPs for the GET and the POSTs. Surely seen that HTTP is a stateless protocol this is perfectly legit right? I'd like to find back the explanation as to how/why certain ISP have their networks configured such that this may happen. I'm asking because someone asked me to implement the following IP filter and I'm pretty sure it is fundamentally broken code (breaking havoc for at least one major american ISP users). Here's a Java servlet filter that is supposed to protect against some attacks. The reasoning is that: "For any session filter checks that IP address in the request is the same that was used when session was created. So in this case session ID could not be stolen for forming fake sessions." http://www.servletsuite.com/servlets/protectsessionsflt.htm However I'm pretty sure this is inherently broken because there are ISPs where you may see GET and POST coming from different IPs. Any info on this subject is very welcome.

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  • Splitting EJBs and interfaces into separate module -- deployment fails

    - by Hank
    I'm having trouble following this guide to "extract" my interfaces and entities from my EAR to use them from another Web Application: I use NetBeans 6.8 and Glassfish 3.0.1 "Java Class Library" project contains all the entities and interfaces "Java EE Application" project class library added to the project, is packaged into the EAR contains EJB implementations, MDBs, Test "Java Web Application" project class library added to the project, is packaged into the WAR contains REST interface When I build and deploy the Web Application, all goes well. When I build the JEE application, I can see the jar-file (interfaces, entities) being included. But when I try to deploy the EAR, Glassfish refuses it with a java.lang.NoClassDefFoundError error: [#|2010-03-28T18:25:59.875+0200|WARNING|glassfishv3.0|javax.enterprise.system.tools.deployment.org.glassfish.deployment.common|_ThreadID=28;_ThreadName=Thread-1;|Error in annotation processing: java.lang.NoClassDefFoundError: mvs/core/StoreServiceLocal|#] [#|2010-03-28T18:25:59.876+0200|SEVERE|glassfishv3.0|javax.enterprise.system.core.com.sun.enterprise.v3.server|_ThreadID=28;_ThreadName=Thread-1;|Exception while deploying the app java.lang.IllegalArgumentException: Invalid ejb jar [CoreServer]: it contains zero ejb. Note: 1. A valid ejb jar requires at least one session, entity (1.x/2.x style), or message-driven bean. 2. EJB3+ entity beans (@Entity) are POJOs and please package them as library jar. 3. If the jar file contains valid EJBs which are annotated with EJB component level annotations (@Stateless, @Stateful, @MessageDriven, @Singleton), please check server.log to see whether the annotations were processed properly. 'mvs/core/StoreServiceLocal' is an interface which is defined in the library jar file. What am I doing wrong?

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  • Concurrent WCF calls via shared channel

    - by Kent Boogaart
    I have a web tier that forwards calls onto an application tier. The web tier uses a shared, cached channel to do so. The application tier services in question are stateless and have concurrency enabled. But they are not being called concurrently. If I alter the web tier to create a new channel on every call, then I do get concurrent calls onto the application tier. But I wanted to avoid that cost since it is functionally unnecessary for my scenario. I have no session state, and nor do I need to re-authenticate the caller each time. I understand that the creation of the channel factory is far more expensive than than the creation of the channels, but it is still a cost I'd like to avoid if possible. I found this article on MSDN that states: While channels and clients created by the channels are thread-safe, they might not support writing more than one message to the wire concurrently. If you are sending large messages, particularly if streaming, the send operation might block waiting for another send to complete. Firstly, I'm not sending large messages (just a lot of small ones since I'm doing load testing) but am still seeing the blocking behavior. Secondly, this is rather open-ended and unhelpful documentation. It says they "might not" support writing more than one message but doesn't explain the scenarios under which they would support concurrent messages. Can anyone shed some light on this?

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  • new Statefull session bean instance without calling lookup

    - by kislo_metal
    Hi! Scenario: I have @Singleton UserFactory (@Stateless could be) , it`s method createSession() generating @Statefull UserSession bean by manual lookup. If I am injecting by DI @EJB - i will get same instance during calling fromFactory() method(as it should be) What I want - is to get new instance of UserSession without preforming lookup. Q1: how could I call new instance of @Statefull session bean? Code: @Singleton @Startup @LocalBean public class UserFactory { @EJB private UserSession session; public UserFactory() { } @Schedule(second = "*/1", minute = "*", hour = "*") public void creatingInstances(){ try { InitialContext ctx = new InitialContext(); UserSession session2 = (UserSession) ctx.lookup("java:global/inferno/lic/UserSession"); System.out.println("in singleton UUID " +session2.getSessionUUID()); } catch (NamingException e) { e.printStackTrace(); } } @Schedule(second = "*/1", minute = "*", hour = "*") public void fromFactory(){ System.out.println("in singleton UUID " +session.getSessionUUID()); } public UserSession creatSession(){ UserSession session2 = null; try { InitialContext ctx = new InitialContext(); session2 = (UserSession) ctx.lookup("java:global/inferno/lic/UserSession"); System.out.println("in singleton UUID " +session2.getSessionUUID()); } catch (NamingException e) { e.printStackTrace(); } return session2; } } As I understand, calling of session.getClass().newInstance(); is not a best idea Q2 : is it true? I am using glassfish v3, ejb 3.1.

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  • How does CDI injection work in MDBs and @Scheduled beans?

    - by Nils-Petter Nilsen
    I'm working on a large Java EE 6 application that is deployed on JBoss 6 Final. My current tasks involve using @Inject consistently instead of @EJB, but I'm running into some problems on some types of beans, specifically @MessageDriven beans and beans with @Scheduled methods. What happens is that if I'm unlucky with the timing (for @Schedule) or if there are messages in the MDBs' queues at startup, instantiation of the beans will fail because the injected resources (which are EJBs themselves) are not bound yet. Because I use @Inject, I'm guessing that the EJB container considers my beans to be ready, since the container itself does not care about @Inject; it probably simply assumes that since there are no @EJB injections, the beans are ready for use. The injected CDI proxies will then fail because the resources to inject aren't actually bound yet. Tiny example: @Stateless @LocalBean public class MySupportingBean { public void doSomething() { ... } } @Singleton public class MyScheduledBean { @Inject private MySupportingBean supportingBean; @Schedule(second = "*/1", hour = "*", minute = "*", persistent = false) public void onTimeout() { supportingBean.doSomething(); } } The above example will probably not fail often because there are only two beans, but the project I'm working on binds lots of EJBs, which will amplify the problem. But it might fail because there is no guarantee that MySupportingBean is bound first, and if onTimeout is invoked before MySupportingBean is bound, then instantiation of MyScheduledBean will fail. If I used @EJB instead, MyScheduledBean wouldn't be bound until the dependency to MySupportingBean was satisfied. Note that the example will not fail in onTimeout itself, but when CDI attempts to inject MySupportingBean. I've read a lot of posts on different forums where many people argue that @Inject is always better. Generally, I agree, but how do they handle @Schedule or @MessageDriven combined with @Inject? In my experience, it comes down to dumb luck whether the beans will work or not in those cases, and the beans will fail arbitrarily, depending on which order the EJBs are deployed in, and when @Schedule or onMessage are invoked.

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  • How do you organise your MVC controller tests?

    - by Andrew Bullock
    I'm looking for tidy suggestions on how people organise their controller tests. For example, take the "add" functionality of my "Address" controller, [AcceptVerbs(HttpVerbs.Get)] public ActionResult Add() { var editAddress = new DTOEditAddress(); editAddress.Address = new Address(); editAddress.Countries = countryService.GetCountries(); return View("Add", editAddress); } [RequireRole(Role = Role.Write)] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Add(FormCollection form) { // save code here } I might have a fixture called "when_adding_an_address", however there are two actions i need to test under this title... I don't want to call both actions in my Act() method in my fixture, so I divide the fixture in half, but then how do I name it? "When_adding_an_address_GET" and "When_adding_an_address_POST"? things just seems to be getting messy, quickly. Also, how do you deal with stateless/setupless assertions for controllers, and how do you arrange these wrt the above? for example: [Test] public void the_requesting_user_must_have_write_permissions_to_POST() { Assert.IsTrue(this.SubjectUnderTest.ActionIsProtectedByRole(c => c.Add(null), Role.Write)); } This is custom code i know, but you should get the idea, it simply checks that a filter attribute is present on the method. The point is it doesnt require any Arrange() or Act(). Any tips welcome! Thanks

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  • What is the best prctice for using security in JAX-WS

    - by kislo_metal
    Here is scenario : I have some web services (JAX-WS) that need to be secured. Currently for authentication needs I providing addition SecurityWService that give authorized user some userid & sessionid that is need to be described in request to other services. It would be more better to use some java security. We have many of them but could not defined what is better to use. Q1 : It is understand that I should use SSL in transport layer, but what should I use for user authorization. Is there is better way to establishing session, validating user etc. ? Here is some key description : Most web services clents is php based. I am using jax-ws implementation as a Stateless session EJB. Deploying to glassfish v3. Q2: what is the best framework / technology for user authorization / authentication in case of using JSF 2.0 and ejb3.1 technologies ( Realms? WSIT? )? Thank You!

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  • Is it bad practice to have state in a static class?

    - by Matthew
    I would like to do something like this: public class Foo { // Probably really a Guid, but I'm using a string here for simplicity's sake. string Id { get; set; } int Data { get; set; } public Foo (int data) { ... } ... } public static class FooManager { Dictionary<string, Foo> foos = new Dictionary<string, Foo> (); public static Foo Get (string id) { return foos [id]; } public static Foo Add (int data) { Foo foo = new Foo (data); foos.Add (foo.Id, foo); return foo; } public static bool Remove (string id) { return foos.Remove (id); } ... // Other members, perhaps events for when Foos are added or removed, etc. } This would allow me to manage the global collection of Foos from anywhere. However, I've been told that static classes should always be stateless--you shouldn't use them to store global data. Global data in general seems to be frowned upon. If I shouldn't use a static class, what is the right way to approach this problem? Note: I did find a similar question, but the answer given doesn't really apply in my case.

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  • Regular input in ASP.NET

    - by coffeeaddict
    Here's an example of a regular standard HTML input for my radiobuttonlist: <label><input type="radio" name="rbRSelectionGroup" checked value="0" />None</label> <asp:Repeater ID="rptRsOptions" runat="server"> <ItemTemplate> <div> <label><input type="radio" name="rbRSelectionGroup" value='<%# ((RItem)Container.DataItem).Id %>' /><%# ((RItem)Container.DataItem).Name %></label> </div> </ItemTemplate> </asp:Repeater> I removed some stuff for this thread, one being I put an r for some name that I do not want to expose here so just an fyi. Now, I would assume that this would or should happen: Page loads the first time, the None radio button is checked / defaulted I go and select a different radiobutton in this radiobutton list I do an F5 refresh in my browser The None radio button is pre-selected again after it has come back from the refresh but #4 is not happening. It's retaining the radiobutton that I selected in #2 and I don't know why. I mean in regular HTML it's stateless. So what could be holding this value? I want this to act like a normal input button. I know the question of "why not use an ASP.NET control" will come up. Well there are 2 reasons: The stupid radiobuttonlist bug that everyone knows about I just want to brush up more on standard input tags We are not moving to MVC so this is as close as I'll get and it's ok, because the rest of the team is on par with having mixed ASP.NET controls with standard HTML controls in our pages Anyway my main question here is I'm surprised that it's retaining the change in selection after postback.

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  • Ideas in implenting the following entry form in ASP.NET MVC 2

    - by KiD0M4N
    Hi guys, I have a very simple data entry form to implement. It looks like this: Obviously I have mocked out the actual requirements but the essence is similar. Entering a name and clicking history should bring up a pop up pointing to the url '/student/viewhistory/{name}' Name and age are required fields The sub form (in the mockup) with Class (a drop down, containing the numbers 1 - 10) and Subject (containing A - D, say) form a unique pair of values for which a score is required. So, selecting the Class and Subject, entering a score and clicking on Add should 'add' this record for the student. Then the user should be able to click Save (to persist the entry to the database) or be able to add further (class, subject, score) pairs to the entry. Any ideas how to smartly implement this? (I am coming from a DWH field... so thinking in a stateless manner is slightly foreign to me.) Any help is appreciated. I would imagine a smart use of jQuery would give a easy solution. Regards, Karan

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  • What's the best way to transfer a large dataset over a .NET web service?

    - by Malvineous
    I've inherited a C# .NET application which talks to a web service, and the web service talks to an Oracle database. I need to add an export function to the UI, to produce an Excel spreadsheet of some of the data. I have created a web service function to run a database query, load the data into a DataTable and then return it, which works fine for a small number of rows. However there is enough data in the full run that the client application locks up for a few minutes and then returns a timeout error. Obviously this isn't the best way to retrieve such a large dataset. Before I go ahead and come up with some dodgy way of splitting the call, I'm wondering if there is already something in place that can handle this. At the moment I'm thinking of a startExport function then repeatedly calling a next50Rows function until there is no data left, but because web services are stateless this means I'm going to have to keep some sort of ID number around and deal with the associated permissions. It would mean that I don't have to load the entire data set into the web server's memory though, which is one good thing. So if anyone knows a better way to retrieve a large amount of data (in a table format) over a .NET web service, please let me know!

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  • What is the correct stage to use for Google Guice in production in an application server?

    - by Yishai
    It seems like a strange question (the obvious answer would Production, duh), but if you read the java docs: /** * We want fast startup times at the expense of runtime performance and some up front error * checking. */ DEVELOPMENT, /** * We want to catch errors as early as possible and take performance hits up front. */ PRODUCTION Assuming a scenario where you have a stateless call to an application server, the initial receiving method (or there abouts) creates the injector new every call. If there all of the module bindings are not needed in a given call, then it would seem to have been better to use the Development stage (which is the default) and not take the performance hit upfront, because you may never take it at all, and here the distinction between "upfront" and "runtime performance" is kind of moot, as it is one call. Of course the downside of this would appear to be that you would lose the error checking, causing potential code paths to cause a problem by surprise. So the question boils down to are the assumptions in the above correct? Will you save performance on a large set of modules when the given lifetime of an injector is one call?

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  • new Stateful session bean instance without calling lookup

    - by kislo_metal
    Scenario: I have @Singleton UserFactory (@Stateless could be) , its method createSession() generating @Stateful UserSession bean by manual lookup. If I am injecting by DI @EJB - i will get same instance during calling fromFactory() method(as it should be) What I want - is to get new instance of UserSession without preforming lookup. Q1: how could I call new instance of @Stateful session bean? Code: @Singleton @Startup @LocalBean public class UserFactory { @EJB private UserSession session; public UserFactory() { } @Schedule(second = "*/1", minute = "*", hour = "*") public void creatingInstances(){ try { InitialContext ctx = new InitialContext(); UserSession session2 = (UserSession) ctx.lookup("java:global/inferno/lic/UserSession"); System.out.println("in singleton UUID " +session2.getSessionUUID()); } catch (NamingException e) { e.printStackTrace(); } } @Schedule(second = "*/1", minute = "*", hour = "*") public void fromFactory(){ System.out.println("in singleton UUID " +session.getSessionUUID()); } public UserSession creatSession(){ UserSession session2 = null; try { InitialContext ctx = new InitialContext(); session2 = (UserSession) ctx.lookup("java:global/inferno/lic/UserSession"); System.out.println("in singleton UUID " +session2.getSessionUUID()); } catch (NamingException e) { e.printStackTrace(); } return session2; } } As I understand, calling of session.getClass().newInstance(); is not a best idea Q2 : is it true? I am using glassfish v3, ejb 3.1.

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  • NHibernate - Retrieving Lots of Data Becomes Exponentially Slow

    - by nfplee
    Hi, I have an issue when I retrieve lots of data in NHibernate (such as when producing a report) the page becomes exponentially slower the more data it has to retrieve. I found the following article: http://nhforge.org/blogs/nhibernate/archive/2008/10/30/bulk-data-operations-with-nhibernate-s-stateless-sessions.aspx It explains how doing bulk data operations in NHibernate is slow since the first level cache grows too large and how you should use the IStatelessSession instead. The trouble I have is that I don't wish to tie my application to NHibernate so I've added a wrapper around ISession. I then use Linq as my query mechanism but IStatelessSession does not support Linq (it may do in NHibernate 3 but the Linq provider is not stable as it stands at the moment). I then read that you could do a clear after so many iterations to clear out the first level cache. The problem now is that you can't use lazy loading. The linq provider doesn't allow you to override the mapping defined (or eagerly fetch the additional data) so whenever I grab data which is lazy loaded after I have cleared the session an exception is thrown. I'm completely lost on what do now. I like the ease of producing reports with linq but the limitations of the inbuilt linq provider in NHibernate seem to be holding me back. I'd really appreciate it if someone could show me an alternative approach. Thanks

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  • Looking for Simplified Overview of EJB3

    - by sdoca
    Hi I'm looking for a simplified overview of EJB3 components. I seem to understand most of the pieces of the puzzle, but can't quite get them to fit together in my brain as a full picture. I've developed numerous web applications (wars) that have been deployed on Tomcat before, but not a full-fledged EE application (ear). I would like the overview to be as generic as possible. I'm not looking for a tutorial on how to set up EJB3 on Glassfish built in NetBeans or some other vendor specific tutorial that's more about the IDE than the technology. I keep reading about Java, ejb-jar, web and ear modules but am not clear on what these different modules contain and how to use them to put together my app. In my case, I want to write a simple database CRUD web application. The first step is simple; create entity classes that model the database tables my app will be using. I plan on using annotations. Should I create a jar that contains just these enity classes? Is this the ejb-jar module (sometimes referred to as the Java module)? Next, I'll need some business logic classes that make use of the entity classes. These are the session beans (stateless or stateful) correct? Should these be packaged in the same jar as the entity classes or a separate jar? Finally, I'll need some sort of web interface (I'll be creating a JSF portlet) application that makes use of the both the session and entity beans. Together with the above jar(s), this will be my war? Assuming the above to be correct, what is involved in creating an ear? Forgive me if this post is vague, but I'm having a hard time defining what it is I don't understand. Thanks for any help!

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  • Business Tier | client state in desktop application- way around Stateful Session Beans?

    - by arthur
    I read positive inputs on the following posts concerning client state management: Stateful EJBs in web application?, here, and here. I want to know how implement such client state management for desktop applications (Swing, AWT, SWT, and other). let's assume there are n desktop clients supposed to use some (remote) services provided on an Application Server. How to maintain a separate and permanent data state for each client , distinct from the other without have to use using stateful session Beans (SFSB) ? is that even possible on this application type ? With Webapp(Servlets / JsSF and JSP) some can avoid using SFSB by HttpSession object and/or coupling it with stateless session beans (SLSB). HttpSession object would keep information for each (Web)client separate and the SLSB would play the business logic music. But HttpSession objects aren't present on desktop application and I go stuck with only SFSB and SLSB. Knowing the problems(Concurrency, Error Handling, usw ) of SFSB, I would have not wanted to use it. What would be the other options? is there only SFSB available? Thanks in advances

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  • When is a Web Service constructor called? [Java Netbeans 6.7.1 & Tomcat 6.0.18]

    - by Shaitan00
    I am migrating a Java RMI application to Java Web Service (school assignment) and I've encountered an issue... Currently my Java Server creates an instance of the Remote Object, this object has a constructor and takes a parameter (int ID) which tells it which database to load in memory - works like a charm ... Now, migrating this to Web Services is causing my a problem - first I needed to add a default constructor because it wouldn't deploy without it, and then while doing some reading all these discussions about "stateless web services" kept coming up ... For example, if I "start" my webservice with parameter(0) it would load from Databse 0 and all requests from Clients would be done using that data... I want this to only happen when I start the WebService and NOT everytime the client connects... Loading from the DB is expensive and takes time, so I want to do it once so that clients when they connect just deal with the data in memory ... This is how it works with my Java RMI .... but can this also work with Web Services? Any advice would be much appreciated. Thanks,

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  • Is a web-server (e.g servlets) a good solution for an IM server?

    - by John
    I'm looking at a new app, broadly speaking an IM application with a strong client-server model - all communications go through a server so they can be logged centrally. The server will be Java in some form, clients could at this point be anything from a .NET Desktop app to Flex/Silverlight, to a simple web-interface using JS/AJAX. I had anticipated doing the server using standard J2EE so I get a thread-safe, multi-user server for 'free'... to make things simple let's say using Servlets (but in practice SpringMVC would be likely). This all seemed very neat but I'm concerned if the stateless nature of Servlets is the best approach. If my memory of servlets (been a year or two) is right, each time a client sent a HTTP request, typically a new message entered by the user, the servlet could not assume it had the user/chat in memory and might have to get it from the DB... regardless it has to look it up. Then it either has to use some PUSH system to inform other members of the chat, or cache that there are new messages, for other clients who poll the server using AJAX or similar - and when they poll it again has to lookup the chat, including new messages, and send the new data. I'm wondering if a better system would be the server is running core Java, and implements a socket-based communication with clients. This allows much more immediate data transfer and is more flexible if say the IM client included some game you could play. But then you're writing a custom server and sockets don't sound very friendly to a browser-based client on current browsers. Am I missing some big piece of the puzzle here, it kind of feels like I am? Perhaps a better way to ask the question would simply be "if the client was browser-based using HTML/JS and had to run on IE7+,FF2+ (i.e no HTML5), how would you implement the server?" edit: if you are going to suggest using XMPP, I have been trying to get my head around this in another question, so please consider if that's a more appropriate place to discuss this specifically.

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  • EntityManager injection works in JBoss 7.1.1 but not WebSphere 7

    - by BikerJared
    I've built an EJB that will manage my database access. I'm building a web app around it that uses Struts 2. The problem I'm having is when I deploy the ear, the EntityManager doesn't get injected into my service class (and winds up null and results in NullPointerExceptions). The weird thing is, it works on JBoss 7.1.1 but not on WebSphere 7. You'll notice that Struts doesn't inject the EJB, so I've got some intercepter code that does that. My current working theory right now is that the WS7 container can't inject the EntityManager because of Struts for some unknown reason. My next step is to try Spring next, but I'd really like to get this to work if possible. I've spent a few days searching and trying various things and haven't had any luck. I figured I'd give this a shot. Let me know if I can provide additional information. <?xml version="1.0" encoding="UTF-8"?> <persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.0" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"> <persistence-unit name="JPATestPU" transaction-type="JTA"> <description>JPATest Persistence Unit</description> <jta-data-source>jdbc/Test-DS</jta-data-source> <class>org.jaredstevens.jpatest.db.entities.User</class> <properties> <property name="hibernate.hbm2ddl.auto" value="update"/> </properties> </persistence-unit> </persistence> package org.jaredstevens.jpatest.db.entities; import java.io.Serializable; import javax.persistence.*; @Entity @Table public class User implements Serializable { private static final long serialVersionUID = -2643583108587251245L; private long id; private String name; private String email; @Id @GeneratedValue(strategy = GenerationType.TABLE) public long getId() { return id; } public void setId(long id) { this.id = id; } @Column(nullable=false) public String getName() { return this.name; } public void setName( String name ) { this.name = name; } @Column(nullable=false) public String getEmail() { return this.email; } @Column(nullable=false) public void setEmail( String email ) { this.email= email; } } package org.jaredstevens.jpatest.db.services; import java.util.List; import javax.ejb.Remote; import javax.ejb.Stateless; import javax.ejb.TransactionAttribute; import javax.ejb.TransactionAttributeType; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import javax.persistence.PersistenceContextType; import javax.persistence.Query; import org.jaredstevens.jpatest.db.entities.User; import org.jaredstevens.jpatest.db.interfaces.IUserService; @Stateless(name="UserService",mappedName="UserService") @Remote public class UserService implements IUserService { @PersistenceContext(unitName="JPATestPU",type=PersistenceContextType.TRANSACTION) private EntityManager em; @TransactionAttribute(TransactionAttributeType.REQUIRED) public User getUserById(long userId) { User retVal = null; if(userId > 0) { retVal = (User)this.getEm().find(User.class, userId); } return retVal; } @TransactionAttribute(TransactionAttributeType.REQUIRED) public List<User> getUsers() { List<User> retVal = null; String sql; sql = "SELECT u FROM User u ORDER BY u.id ASC"; Query q = this.getEm().createQuery(sql); retVal = (List<User>)q.getResultList(); return retVal; } @TransactionAttribute(TransactionAttributeType.REQUIRED) public void save(User user) { this.getEm().persist(user); } @TransactionAttribute(TransactionAttributeType.REQUIRED) public boolean remove(long userId) { boolean retVal = false; if(userId > 0) { User user = null; user = (User)this.getEm().find(User.class, userId); if(user != null) this.getEm().remove(user); if(this.getEm().find(User.class, userId) == null) retVal = true; } return retVal; } public EntityManager getEm() { return em; } public void setEm(EntityManager em) { this.em = em; } } package org.jaredstevens.jpatest.actions.user; import javax.ejb.EJB; import org.jaredstevens.jpatest.db.entities.User; import org.jaredstevens.jpatest.db.interfaces.IUserService; import com.opensymphony.xwork2.ActionSupport; public class UserAction extends ActionSupport { @EJB(mappedName="UserService") private IUserService userService; private static final long serialVersionUID = 1L; private String userId; private String name; private String email; private User user; public String getUserById() { String retVal = ActionSupport.SUCCESS; this.setUser(userService.getUserById(Long.parseLong(this.userId))); return retVal; } public String save() { String retVal = ActionSupport.SUCCESS; User user = new User(); if(this.getUserId() != null && Long.parseLong(this.getUserId()) > 0) user.setId(Long.parseLong(this.getUserId())); user.setName(this.getName()); user.setEmail(this.getEmail()); userService.save(user); this.setUser(user); return retVal; } public String getUserId() { return this.userId; } public void setUserId(String userId) { this.userId = userId; } public String getName() { return this.name; } public void setName( String name ) { this.name = name; } public String getEmail() { return this.email; } public void setEmail( String email ) { this.email = email; } public User getUser() { return this.user; } public void setUser(User user) { this.user = user; } } package org.jaredstevens.jpatest.utils; import com.opensymphony.xwork2.ActionInvocation; import com.opensymphony.xwork2.interceptor.Interceptor; public class EJBAnnotationProcessorInterceptor implements Interceptor { private static final long serialVersionUID = 1L; public void destroy() { } public void init() { } public String intercept(ActionInvocation ai) throws Exception { EJBAnnotationProcessor.process(ai.getAction()); return ai.invoke(); } } package org.jaredstevens.jpatest.utils; import java.lang.reflect.Field; import javax.ejb.EJB; import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NamingException; public class EJBAnnotationProcessor { public static void process(Object instance)throws Exception{ Field[] fields = instance.getClass().getDeclaredFields(); if(fields != null && fields.length > 0){ EJB ejb; for(Field field : fields){ ejb = field.getAnnotation(EJB.class); if(ejb != null){ field.setAccessible(true); field.set(instance, EJBAnnotationProcessor.getEJB(ejb.mappedName())); } } } } private static Object getEJB(String mappedName) { Object retVal = null; String path = ""; Context cxt = null; String[] paths = {"cell/nodes/virgoNode01/servers/server1/","java:module/"}; for( int i=0; i < paths.length; ++i ) { try { path = paths[i]+mappedName; cxt = new InitialContext(); retVal = cxt.lookup(path); if(retVal != null) break; } catch (NamingException e) { retVal = null; } } return retVal; } } <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <constant name="struts.devMode" value="true" /> <package name="basicstruts2" namespace="/diagnostics" extends="struts-default"> <interceptors> <interceptor name="ejbAnnotationProcessor" class="org.jaredstevens.jpatest.utils.EJBAnnotationProcessorInterceptor"/> <interceptor-stack name="baseStack"> <interceptor-ref name="defaultStack"/> <interceptor-ref name="ejbAnnotationProcessor"/> </interceptor-stack> </interceptors> <default-interceptor-ref name="baseStack"/> </package> <package name="restAPI" namespace="/conduit" extends="json-default"> <interceptors> <interceptor name="ejbAnnotationProcessor" class="org.jaredstevens.jpatest.utils.EJBAnnotationProcessorInterceptor" /> <interceptor-stack name="baseStack"> <interceptor-ref name="defaultStack" /> <interceptor-ref name="ejbAnnotationProcessor" /> </interceptor-stack> </interceptors> <default-interceptor-ref name="baseStack" /> <action name="UserAction.getUserById" class="org.jaredstevens.jpatest.actions.user.UserAction" method="getUserById"> <result type="json"> <param name="ignoreHierarchy">false</param> <param name="includeProperties"> ^user\.id, ^user\.name, ^user\.email </param> </result> <result name="error" type="json" /> </action> <action name="UserAction.save" class="org.jaredstevens.jpatest.actions.user.UserAction" method="save"> <result type="json"> <param name="ignoreHierarchy">false</param> <param name="includeProperties"> ^user\.id, ^user\.name, ^user\.email </param> </result> <result name="error" type="json" /> </action> </package> </struts> Stack Trace java.lang.NullPointerException org.jaredstevens.jpatest.actions.user.UserAction.save(UserAction.java:38) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:60) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37) java.lang.reflect.Method.invoke(Method.java:611) com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:453) com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:292) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:255) org.jaredstevens.jpatest.utils.EJBAnnotationProcessorInterceptor.intercept(EJBAnnotationProcessorInterceptor.java:21) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:176) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265) org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:211) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:211) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:190) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:90) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:243) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:192) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54) org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:511) org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77) org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91) com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:188) com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:116) com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:77) com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:908) com.ibm.ws.webcontainer.filter.WebAppFilterManager.invokeFilters(WebAppFilterManager.java:997) com.ibm.ws.webcontainer.extension.DefaultExtensionProcessor.invokeFilters(DefaultExtensionProcessor.java:1062) com.ibm.ws.webcontainer.extension.DefaultExtensionProcessor.handleRequest(DefaultExtensionProcessor.java:982) com.ibm.ws.webcontainer.webapp.WebApp.handleRequest(WebApp.java:3935) com.ibm.ws.webcontainer.webapp.WebGroup.handleRequest(WebGroup.java:276) com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:931) com.ibm.ws.webcontainer.WSWebContainer.handleRequest(WSWebContainer.java:1583) com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:186) com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:452) com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:511) com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:305) com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpInboundLink.java:276) com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.sendToDiscriminators(NewConnectionInitialReadCallback.java:214) com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.complete(NewConnectionInitialReadCallback.java:113) com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165) com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217) com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161) com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:138) com.ibm.io.async.ResultHandler.complete(ResultHandler.java:204) com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:775) com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:905) com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1604)

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  • Oracle Enterprise Data Quality: Ever Integration-ready

    - by Mala Narasimharajan
    It is closing in on a year now since Oracle’s acquisition of Datanomic, and the addition of Oracle Enterprise Data Quality (EDQ) to the Oracle software family. The big move has caused some big shifts in emphasis and some very encouraging excitement from the field.  To give an illustration, combined with a shameless promotion of how EDQ can help to give quick insights into your data, I did a quick Phrase Profile of the subject field of emails to the Global EDQ mailing list since it was set up last September. The results revealed a very clear theme:   Integration, Integration, Integration! As well as the important Siebel and Oracle Data Integrator (ODI) integrations, we have been asked about integration with a huge variety of Oracle applications, including EBS, Peoplesoft, CRM on Demand, Fusion, DRM, Endeca, RightNow, and more - and we have not stood still! While it would not have been possible to develop specific pre-integrations with all of the above within a year, we have developed a package of feature-rich out-of-the-box web services and batch processes that can be plugged into any application or middleware technology with ease. And with Siebel, they work out of the box. Oracle Enterprise Data Quality version 9.0.4 includes the Customer Data Services (CDS) pack – a ready set of standard processes with standard interfaces, to provide integrated: Address verification and cleansing  Individual matching Organization matching The services can are suitable for either Batch or Real-Time processing, and are enabled for international data, with simple configuration options driving the set of locale-specific dictionaries that are used. For example, large dictionaries are provided to support international name transcription and variant matching, including highly specialized handling for Arabic, Japanese, Chinese and Korean data. In total across all locales, CDS includes well over a million dictionary entries.   Excerpt from EDQ’s CDS Individual Name Standardization Dictionary CDS has been developed to replace the OEM of Informatica Identity Resolution (IIR) for attached Data Quality on the Oracle price list, but does this in a way that creates a ‘best of both worlds’ situation for customers, who can harness not only the out-of-the-box functionality of pre-packaged matching and standardization services, but also the flexibility of OEDQ if they want to customize the interfaces or the process logic, without having to learn more than one product. From a competitive point of view, we believe this stands us in good stead against our key competitors, including Informatica, who have separate ‘Identity Resolution’ and general DQ products, and IBM, who provide limited out-of-the-box capabilities (with a steep learning curve) in both their QualityStage data quality and Initiate matching products. Here is a brief guide to the main services provided in the pack: Address Verification and Standardization EDQ’s CDS Address Cleaning Process The Address Verification and Standardization service uses EDQ Address Verification (an OEM of Loqate software) to verify and clean addresses in either real-time or batch. The Address Verification processor is wrapped in an EDQ process – this adds significant capabilities over calling the underlying Address Verification API directly, specifically: Country-specific thresholds to determine when to accept the verification result (and therefore to change the input address) based on the confidence level of the API Optimization of address verification by pre-standardizing data where required Formatting of output addresses into the input address fields normally used by applications Adding descriptions of the address verification and geocoding return codes The process can then be used to provide real-time and batch address cleansing in any application; such as a simple web page calling address cleaning and geocoding as part of a check on individual data.     Duplicate Prevention Unlike Informatica Identity Resolution (IIR), EDQ uses stateless services for duplicate prevention to avoid issues caused by complex replication and synchronization of large volume customer data. When a record is added or updated in an application, the EDQ Cluster Key Generation service is called, and returns a number of key values. These are used to select other records (‘candidates’) that may match in the application data (which has been pre-seeded with keys using the same service). The ‘driving record’ (the new or updated record) is then presented along with all selected candidates to the EDQ Matching Service, which decides which of the candidates are a good match with the driving record, and scores them according to the strength of match. In this model, complex multi-locale EDQ techniques can be used to generate the keys and ensure that the right balance between performance and matching effectiveness is maintained, while ensuring that the application retains control of data integrity and transactional commits. The process is explained below: EDQ Duplicate Prevention Architecture Note that where the integration is with a hub, there may be an additional call to the Cluster Key Generation service if the master record has changed due to merges with other records (and therefore needs to have new key values generated before commit). Batch Matching In order to allow customers to use different match rules in batch to real-time, separate matching templates are provided for batch matching. For example, some customers want to minimize intervention in key user flows (such as adding new customers) in front end applications, but to conduct a more exhaustive match on a regular basis in the back office. The batch matching jobs are also used when migrating data between systems, and in this case normally a more precise (and automated) type of matching is required, in order to minimize the review work performed by Data Stewards.  In batch matching, data is captured into EDQ using its standard interfaces, and records are standardized, clustered and matched in an EDQ job before matches are written out. As with all EDQ jobs, batch matching may be called from Oracle Data Integrator (ODI) if required. When working with Siebel CRM (or master data in Siebel UCM), Siebel’s Data Quality Manager is used to instigate batch jobs, and a shared staging database is used to write records for matching and to consume match results. The CDS batch matching processes automatically adjust to Siebel’s ‘Full Match’ (match all records against each other) and ‘Incremental Match’ (match a subset of records against all of their selected candidates) modes. The Future The Customer Data Services Pack is an important part of the Oracle strategy for EDQ, offering a clear path to making Data Quality Assurance an integral part of enterprise applications, and providing a strong value proposition for adopting EDQ. We are planning various additions and improvements, including: An out-of-the-box Data Quality Dashboard Even more comprehensive international data handling Address search (suggesting multiple results) Integrated address matching The EDQ Customer Data Services Pack is part of the Enterprise Data Quality Media Pack, available for download at http://www.oracle.com/technetwork/middleware/oedq/downloads/index.html.

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  • Windows Azure Use Case: Hybrid Applications

    - by BuckWoody
    This is one in a series of posts on when and where to use a distributed architecture design in your organization's computing needs. You can find the main post here: http://blogs.msdn.com/b/buckwoody/archive/2011/01/18/windows-azure-and-sql-azure-use-cases.aspx  Description: Organizations see the need for computing infrastructures that they can “rent” or pay for only when they need them. They also understand the benefits of distributed computing, but do not want to create this infrastructure themselves. However, they may have considerations that prevent them from moving all of their current IT investment to a distributed environment: Private data (do not want to send or store sensitive data off-site) High dollar investment in current infrastructure Applications currently running well, but may need additional periodic capacity Current applications not designed in a stateless fashion In these situations, a “hybrid” approach works best. In fact, with Windows Azure, a hybrid approach is an optimal way to implement distributed computing even when the stipulations above do not apply. Keeping a majority of the computing function in an organization local while exploring and expanding that footprint into Windows and SQL Azure is a good migration or expansion strategy. A “hybrid” architecture merely means that part of a computing cycle is shared between two architectures. For instance, some level of computing might be done in a Windows Azure web-based application, while the data is stored locally at the organization. Implementation: There are multiple methods for implementing a hybrid architecture, in a spectrum from very little interaction from the local infrastructure to Windows or SQL Azure. The patterns fall into two broad schemas, and even these can be mixed. 1. Client-Centric Hybrid Patterns In this pattern, programs are coded such that the client system sends queries or compute requests to multiple systems. The “client” in this case might be a web-based codeset actually stored on another system (which acts as a client, the user’s device serving as the presentation layer) or a compiled program. In either case, the code on the client requestor carries the burden of defining the layout of the requests. While this pattern is often the easiest to code, it’s the most brittle. Any change in the architecture must be reflected on each client, but this can be mitigated by using a centralized system as the client such as in the web scenario. 2. System-Centric Hybrid Patterns Another approach is to create a distributed architecture by turning on-site systems into “services” that can be called from Windows Azure using the service Bus or the Access Control Services (ACS) capabilities. Code calls from a series of in-process client application. In this pattern you move the “client” interface into the server application logic. If you do not wish to change the application itself, you can “layer” the results of the code return using a product (such as Microsoft BizTalk) that exposes a Web Services Definition Language (WSDL) endpoint to Windows Azure using the Application Fabric. In effect, this is similar to creating a Service Oriented Architecture (SOA) environment, and has the advantage of de-coupling your computing architecture. If each system offers a “service” of the results of some software processing, the operating system or platform becomes immaterial, assuming it adheres to a service contract. There are important considerations when you federate a system, whether to Windows or SQL Azure or any other distributed architecture. While these considerations are consistent with coding any application for distributed computing, they are especially important for a hybrid application. Connection resiliency - Applications on-premise normally have low-latency and good connection properties, something you’re not always guaranteed in a distributed and hybrid application. Whether a centralized client or a distributed one, the code should be able to handle extended retry logic. Authorization and Access - In a single authorization environment like a Active Directory domain, security is handled at a user-password level. In a distributed computing environment, you have more options. You can mitigate this with  using The Windows Azure Application Fabric feature of ACS to make the Azure application aware of the App Fabric as an ADFS provider. However, a claims-based authentication structure is often a superior choice.  Consistency and Concurrency - When you have a Relational Database Management System (RDBMS), Consistency and Concurrency are part of the design. In a Service Architecture, you need to plan for sequential message handling and lifecycle. Resources: How to Build a Hybrid On-Premise/In Cloud Application: http://blogs.msdn.com/b/ignitionshowcase/archive/2010/11/09/how-to-build-a-hybrid-on-premise-in-cloud-application.aspx  General Architecture guidance: http://blogs.msdn.com/b/buckwoody/archive/2010/12/21/windows-azure-learning-plan-architecture.aspx   

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