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• Partner Webcast - Oracle Business Process Management: What’s new in Oracle BPM 11.1.1.7.0 - 04 July 2013

  - by Thanos

  Business processes are at the heart of what makes or breaks a business—and what differentiates it from the competition. Business processes that deliver operational efficiency, business visibility, excellent customer experience, and agility give the enterprise an edge over the competition. Business managers need process management tools that enable them to make impactful changes. Oracle has been always a leader in this area and the new version of Oracle BPM 11g takes that even further by providing complete web based process modeling, simulation and implementation including designing the user interface and business logic. That provides business users with ability to take complete control over the business processes without sacrificing the vast service integration capabilities delivered traditionally by IT using SOA approach. Oracle Business Process Management is the industry's most complete and business user-friendly BPM solution. Register today for this webcast and find out more on the latest and most exciting new features which are now available in Oracle BPM Suite. Agenda Introduction do Oracle BPM 11g Exciting new features in this release Revamped Process Composer Simulations Web Forms Process Player Adaptive Case Management Instance Revisioning Other features Demonstration Q&A Delivery Format This FREE online LIVE eSeminar will be delivered over the Web. Registrations received less than 24hours prior to start time may not receive confirmation to attend. Duration: 1 hour Register Now! For any questions please contact us at [email protected] Visit our ISV Migration Center blog & Facebook Page or Follow us @oracleimc  to learn more on Oracle Technologies, upcoming partner webcasts and events. Existing content available YouTube - SlideShare - Oracle Mix

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• Branding/Restricting a Software by License/Serial

  - by Sid

  I have made a POS System for a client of mine using MS Access Server-Client approach. He asked me to brand his software to allow only a certain "number" of users (cashiers) to access the POS System, and must be determined to the license his client will buy. EX: 10 User License = 10 Cashiers ( not necessarily 10 users, it can be 30 users, shifting) = it means 10 PCs will be installed with the client software I made. How and where do I put the logic that will determine if it is licensed or not. What I have done: I have created a serial key generator using Name. Problem is it can be duplicated once you give than name+serial combination, it would still work. I am counting the number of users logged at a time. This could be problematic as I am using MSAccess and not MSSQL. I have scrapped this idea, He also asked me if I could just put serial+mac address combination. That I could do but he will have a hard time implementing it and selling it if he needs the mac address of every computers to be installed with my POS. I am at lost on what can I do. Would like to ask for tips and suggestions. Thank you.

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• What language and topics should be covered when teaching non-CS college students how to program?

  - by michaelcarrano

  I have been asked by many of my non-computer science friends to teach them how to program. I have agreed to hold a seminar for them that will last for approximately 1 to 2 hours. My thoughts are to use Python as the language to teach them basic programming skills. I figured Python is relatively easier to learn from what I have researched. It is also a language I want to learn which will make holding this seminar all the more enjoyable. The topics I plan to cover are as followed: Variables / Arrays Logic - If else statements, switch case, nested statements Loops - for, while, do-while and nested loops Functions - pass by value, pass by reference (is this the correct terms for Python? I am mostly a C/C++ person) Object Oriented Programming Of course, I plan to have code examples for all topics and I will try to have each example flow into each other so that at the end of the seminar everyone will have a complete working program. I suppose my question is, if you were given 1 to 2 hours to teach a group of college students how to program, what language would you choose and what topics would you cover? Update: Thank you for the great feedback. I should have mentioned in my earlier post above that a majority of the students attending the seminar have some form of programming experience whether it was with Java or using Matlab. Most of these students are 3rd/4th year Engineering students who want to get a refresher on programming before they graduate.

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• How do you avoid name similarities between your classes and the native ones?

  - by Oscar

  I just ran into an "interesting problem", which I would like your opinion about: I am developing a system and for many reasons (meaning: abstraction, technology independence, etc) we create our own types for exchanging information. For instance: if there is a method which is called SendEmail and is invoked by the business logic, it way have a parameter of type OurCompany.EMailMessage, which is an object which is completely technology independent and contains only "business relevant data" (for instance, no information abut head encoding). Inside the SendEmail function, we get this information from our EMailMEssage object and create a MailMessage (this one is technolgy specific) object so it can be sent over the network. As you can already notice, our class has a very similar name to the "native" language class. The problem is: this is exactly what they are, email messages, so it is hard to find another meaningful name for them. Do you have this problem often? How do you manage it? Edit: @mgkrebbs just commented about using fully qualified names. This is our current approach, but a little bit too verbose, IMHO. I would like something cleaner, if possible.

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• Designing business objects, and gui actions

  - by fozz

  Developing a product ordering system using Java SE 6. The previous implementations used combo boxes, text fields, and check boxes. Preforming validation on action events from the GUI. The validation includes limiting existing combo boxes items, or even availability. The issue in the old system was that the action was received and all rules were applied to the entire business object. This resulted in a huge event change as options were changed multiple times. To be honest I have no idea how an infinite loop wasn't produced. Through the next iteration I stepped in and attempted to limit the chaos by controlling the order in which the selections could be made. Making configuration of BO's a top down approach. I implemented custom box models, action events, beans/binding, and an MVC pattern. However I still am unable to fully isolate action even chains. I'm thinking that I've approached the whole concept backwards in an attempt to stay closest to what was already in place. So the question becomes what do I design instead? I'm currently considering an implementation of Interfaces, Beans, Property Change Listeners to manage the back and forth. Other thoughts were validation exceptions, dynamic proxies.... I'm sure there are a ton of different ways. To say that one way is right is crazy, and I'm sure it will take a blending of multiple patterns. My knowledge of swing/awt validation is limited, previously I did backend logic only. Other considerations are were some sort of binding(jgoodies or otherwise) to directly bind GUI state to BO's.

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• how to architect this to make it unit testable

  - by SOfanatic

  I'm currently working on a project where I'm receiving an object via web service (WSDL). The overall process is the following: Receive object - add/delete/update parts (or all) of it - and return the object with the changes made. The thing is that sometimes these changes are complicated and there is some logic involved, other databases, other web services, etc. so to facilitate this I'm creating a custom object that mimics the original one but has some enhanced functionality to make some things easier. So I'm trying to have this process: Receive original object - convert/copy it to custom object - add/delete/update - convert/copy it back to original object - return original object. Example: public class Row { public List<Field> Fields { get; set; } public string RowId { get; set; } public Row() { this.Fields = new List<Field>(); } } public class Field { public string Number { get; set; } public string Value { get; set; } } So for example, one of the "actions" to perform on this would be to find all Fields in a Row that match a Value equal to something, and update them with some other value. I have a CustomRow class that represents the Row class, how can I make this class unit testable? Do I have to create an interface ICustomRow to mock it in the unit test? If one of the actions is to sum all of the Values in the Fields that have a Number equal to 10, like this function, how can design the custom class to facilitate unit tests. Sample function: public int Sum(FieldNumber number) { return row.Fields.Where(x => x.FieldNumber.Equals(number)).Sum(x => x.FieldValue); } Am I approaching this the wrong way?

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• Storing editable site content?

  - by hmp

  We have a Django-based website for which we wanted to make some of the content (text, and business logic such as pricing plans) easily editable in-house, and so we decided to store it outside the codebase. Usually the reason is one of the following: It's something that non-technical people want to edit. One example is copywriting for a website - the programmers prepare a template with text that defaults to "Lorem ipsum...", and the real content is inserted later to the database. It's something that we want to be able to change quickly, without the need to deploy new code (which we currently do twice a week). An example would be features currently available to the customers at different tiers of pricing. Instead of hardcoding these, we read them from database. The described solution is flexible but there are some reasons why I don't like it. Because the content has to be read from the database, there is a performance overhead. We mitigate that by using a caching scheme, but this also adds some complexity to the system. Developers who run the code locally see the system in a significantly different state compared to how it runs on production. Automated tests also exercise the system in a different state. Situations like testing new features on a staging server also get trickier - if the staging server doesn't have a recent copy of the database, it can be unexpectedly different from production. We could mitigate that by committing the new state to the repository occasionally (e.g. by adding data migrations), but it seems like a wrong approach. Is it? Any ideas how best to solve these problems? Is there a better approach for handling the content that I'm overlooking?

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• Dealing with numerous, simultaneous sounds in unity

  - by luxchar

  I've written a custom class that creates a fixed number of audio sources. When a new sound is played, it goes through the class, which creates a queue of sounds that will be played during that frame. The sounds that are closer to the camera are given preference. If new sounds arrive in the next frame, I have a complex set of rules that determines how to replace the old ones. Ideally, "big" or "important" sounds should not be replaced by small ones. Sound replacement is necessary since the game can be fast-paced at times, and should try to play new sounds by replacing old ones. Otherwise, there can be "silent" moments when an old sound is about to stop playing and isn't replaced right away by a new sound. The drawback of replacing old sounds right away is that there is a harsh transition from the old sound clip to the new one. But I wonder if I could just remove that management logic altogether, and create audio sources on the fly for new sounds. I could give "important" sounds more priority (closer to 0 in the corresponding property) as opposed to less important ones, and let Unity take care of culling out sound effects that exceed the channel limit. The only drawback is that it requires many heap allocations. I wonder what strategy people use here?

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• Preferred way for dealing with customer-defined data in enterprise application

  - by Axarydax

  Let's say that we have a small enterprise web (intranet) application for managing data for car dealers. It has screens for managing customers, inventory, orders, warranties and workshops. This application is installed at 10 customer sites for different car dealers. First version of this application was created without any way to provide for customer-specific data. For example, if dealer A wanted to be able to attach a photo to a customer, dealer B wanted to add e-mail contact to each workshop, and dealer C wanted to attach multiple PDF reports to a warranty, each and every feature like this was added to the application, so all of the customers received everything on new update. However, this will inevitably lead to conflicts as the number of customers grow as their usage patterns are unique, and if, for instance, a specific dealer requested to have an ability to attach (for some reason) a color of inventory item (and be able to search by this color) as a required item, others really wouldn't need this feature, and definitely will not want it to be a required item. Or, one dealer would like to manage e-mail contacts for their employees on a separate screen of the application. I imagine that a solution for this is to use a kind of plugin system, where we would have a core of the application that provides for standard features like customers, inventory, etc, and all of the customer's installed plugins. There would be different kinds of plugins - standalone screens like e-mail contacts for employees, with their own logic, and customer plugin which would extend or decorate inventory items (like photo or color). Inventory (customer,order,...) plugins would require to have installation procedure, hooks for plugging into the item editor, item displayer, item filtering for searching, backup hook and such. Is this the right way to solve this problem?

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• Creating shooting arrow class [on hold]

  - by I.Hristov

  OK I am trying to write an XNA game with one controllable by the player entity, while the rest are bots (enemy and friendly) wondering around and... shooting each other from range. Now the shooting I suppose should be done with a separate class Arrow (for example). The resulting object would be the arrow appearing on screen moving from shooting entity to target entity. When target is reached arrow is no longer active, probably removed from the list. I plan to make a class with fields: Vector2 shootingEntity; Vector2 targetEntity; float arrowSpeed; float arrowAttackSpeed; int damageDone; bool isActive; Then when enemy entities get closer than a int rangeToShoot (which each entity will have as a field/prop) I plan to make a list of arrows emerging from each entity and going to the closest opposite one. I wonder if that logic will enable me later to make possible many entities to be able to shoot independently at different enemy entities at the same time. I know the question is broad but it would be wise to ask if the foundations of the idea are correct.

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• Keeping a domain model consistent with actual data

  - by fstuijt

  Recently domain driven design got my attention, and while thinking about how this approach could help us I came across the following problem. In DDD the common approach is to retrieve entities (or better, aggregate roots) from a repository which acts as a in-memory collection of these entities. After these entities have been retrieved, they can be updated or deleted by the user, however after retrieval they are essentially disconnected from the data source and one must actively inform the repository to update the data source and make is consistent again with our in-memory representation. What is the DDD approach to retrieving entities that should remain connected to the data source? For example, in our situation we retrieve a series of sensors that have a specific measurement during retrieval. Over time, these measurement values may change and our business logic in the domain model should respond to these changes properly. E.g., domain events may be raised if a sensor value exceeds a predefined threshold. However, using the repository approach, these sensor values are just snapshots, and are disconnected from the data source. Does any of you have an idea on how to solve this following the DDD approach?

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• List all BPM Processes for a user

  - by kasriniv

  Hello, Happy to start contributing to this blog..  The title of the blog is probably deceptively simple and warrants an elaboration. Customized BPM workspaces/user interfaces are a fairly common requirement. One of our marquee customers in the online stock trading business, envisioned this user interaction for their BPM application: User logs in to the internal portal Use will have list of roles which he is granted as a drop down list Once user selects the role, a list of processes which user is part of appear. Logged in user can be part of any swimlane role of the process This can be a fairly common/reasonable user-UI interaction pattern. 1. and 2. are easily achievable and hence the subject matter of this blog is the requirement in 3. Objective: Given a username and a role, list all the BPM processes that the user is part of, in any swimlane of any process. Here is quick overview of the major steps/logic in the code: Intialize workflow/BPM  context as usual Get a handle on InstanceQueryService(getInstanceQueryService), InstanceManagementService,        ProcessMetadataService and ProcessModelService List all Processes for that bpmcontext (listProcessMetadataSumary) and get Granted roles to that user For each of the processes [method  getAccessibleProcesss(ProcessMetadataSummary, Set)]for each of the lanes in the process, check if the role granted to the user, matches the roleName for that swimlane. If so, add to output. Notes: The usual caveats apply including BPM APIs are subject to change.  JDeveloper method introspection is your better friend than API documentation :-)... (I am going to try upload the source code  and if it doesnt work, will follow this blog up with the corresponding source code.) Hope this helps.  Ack: Yogesh K, BPM Dev team.

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• Do cross reference database tables have a place in domain driven design?

  - by Mike Cellini

  First some background. Let's say we have a system where a customer is placing an order in a web interface. The items that customer is ordering can priced in various ways. Sometimes including the cost of delivery and sometimes not at all. That pricing effectively depends on a variety of factors including the vendor's own pricing model, that vendor's individual contracts with customers as well as that vendor's contracts with its own suppliers. Let's assume that once a customer places an order for a particular item and chooses a contract if any, the method of delivery can be determined by variables on those contracts. Those delivery methods also live in their own table in the database and have various properties consumed downstream. It makes sense that a cross reference or lookup table would store that information. That table would be loaded into the domain and could then be used to apply the appropriate delivery method while processing the order. Does this make sense in the context of domain driven design? Or is my thinking too relational? Is this logic that should be built into it's own class/method (I mean beyond apply the cross reference table data)?

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• How do you plan your asynchronous code?

  - by NullOrEmpty

  I created a library that is a invoker for a web service somewhere else. The library exposes asynchronous methods, since web service calls are a good candidate for that matter. At the beginning everything was just fine, I had methods with easy to understand operations in a CRUD fashion, since the library is a kind of repository. But then business logic started to become complex, and some of the procedures involves the chaining of many of these asynchronous operations, sometimes with different paths depending on the result value, etc.. etc.. Suddenly, everything is very messy, to stop the execution in a break point it is not very helpful, to find out what is going on or where in the process timeline have you stopped become a pain... Development becomes less quick, less agile, and to catch those bugs that happens once in a 1000 times becomes a hell. From the technical point, a repository that exposes asynchronous methods looked like a good idea, because some persistence layers could have delays, and you can use the async approach to do the most of your hardware. But from the functional point of view, things became very complex, and considering those procedures where a dozen of different calls were needed... I don't know the real value of the improvement. After read about TPL for a while, it looked like a good idea for managing tasks, but in the moment you have to combine them and start to reuse existing functionality, things become very messy. I have had a good experience using it for very concrete scenarios, but bad experience using them broadly. How do you work asynchronously? Do you use it always? Or just for long running processes? Thanks.

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• what's a good approach to working with multiple databases?

  - by Riz

  I'm working on a project that has its own database call it InternalDb, but also it queries two other databases, call them ExternalDb1 and ExternalDb2. Both ExternalDb1 and ExternalDb2 are actually required by a few other projects. I'm wondering what the best approach for dealing with this is? Currently, I've just created a project for each of these external databases and then generated Edmx and entities using the entity-framework approach. My thought was that I could then include these projects in any of my solutions that require access to these databases. Also, I don't have any separate business layers. I just have a solution like below: Project.Domain ExternalDb1Project.Domain ExternalDb2Project.Domain Project.Web So my Domain projects contain the data access as well as the POCOs generated by Entity Framework and any business logic. But I'm not sure if this is a good approach. For example if I want to do Validation in my Project.Domain on the entities in the InternalDb, it's fine. But if I want to do Validation for entities from either of the ExternalDbs, then I wonder where it should go? To be more specific, I retrieve Employees from ExternalDb1Project.Domain. However, I want to make sure they are Active. Where should this Validation go? How to architect a project like this at a high level? Also, I want to make sure that I use IoC for my data contexts so I can create Fakes when writing tests. I wonder where the interfaces for these various data contexts would reside?

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• PyQt application architecture

  - by L. De Leo

  I'm trying to give a sound structure to a PyQt application that implements a card game. So far I have the following classes: Ui_Game: this describes the ui of course and is responsible of reacting to the events emitted by my CardWidget instances MainController: this is responsible for managing the whole application: setup and all the subsequent states of the application (like starting a new hand, displaying the notification of state changes on the ui or ending the game) GameEngine: this is a set of classes that implement the whole game logic Now, the way I concretely coded this in Python is the following: class CardWidget(QtGui.QLabel): def __init__(self, filename, *args, **kwargs): QtGui.QLabel.__init__(self, *args, **kwargs) self.setPixmap(QtGui.QPixmap(':/res/res/' + filename)) def mouseReleaseEvent(self, ev): self.emit(QtCore.SIGNAL('card_clicked'), self) class Ui_Game(QtGui.QWidget): def __init__(self, window, *args, **kwargs): QtGui.QWidget.__init__(self, *args, **kwargs) self.setupUi(window) self.controller = None def place_card(self, card): cards_on_table = self.played_cards.count() + 1 print cards_on_table if cards_on_table <= 2: self.played_cards.addWidget(card) if cards_on_table == 2: self.controller.play_hand() class MainController(object): def __init__(self): self.app = QtGui.QApplication(sys.argv) self.window = QtGui.QMainWindow() self.ui = Ui_Game(self.window) self.ui.controller = self self.game_setup() Is there a better way other than injecting the controller into the Ui_Game class in the Ui_Game.controller? Or am I totally off-road?

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• How to pause and resume a game in XNA using the same key?

  - by user13095

  I'm attempting to implement a really simple game state system, this is my first game - trying to make a Tetris clone. I'd consider myself a novice programmer at best. I've been testing it out by drawing different textures to the screen depending on the current state. The 'Not Playing' state seems to work fine, I press Space and it changes to 'Playing', but when I press 'P' to pause or resume the game nothing happens. I tried checking current and previous keyboard states thinking it was happening to fast for me to see, but again nothing seemed to happen. If I change either the pause or resume, so they're both different, it works as intended. I'm clearly missing something obvious, or completely lacking some know-how in regards to how update and/or the keyboard states work. Here's what I have in my Update method at the moment: protected override void Update(GameTime gameTime) { KeyboardState CurrentKeyboardState = Keyboard.GetState(); // Allows the game to exit if (CurrentKeyboardState.IsKeyDown(Keys.Escape)) this.Exit(); // TODO: Add your update logic here if (CurrentGameState == GameStates.NotPlaying) { if (CurrentKeyboardState.IsKeyDown(Keys.Space)) CurrentGameState = GameStates.Playing; } if (CurrentGameState == GameStates.Playing) { if (CurrentKeyboardState.IsKeyDown(Keys.P)) CurrentGameState = GameStates.Paused; } if (CurrentGameState == GameStates.Paused) { if (CurrentKeyboardState.IsKeyDown(Keys.P)) CurrentGameState = GameStates.Playing; } base.Update(gameTime); }

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• GLES2.0 3D Android game performance and multi threading the update?

  - by Ofer

  I have profiled my mixed Java\C++ Android game and I got the following result: https://dl.dropbox.com/u/8025882/PompiDev/AndroidProfile.png As you can see, the pink think is a C++ functions that updates the game. It does things like updating the logic but it mostly it generates a "request list" for rendering. The thing is, I generate DrawLists on C++ and then send them to Java to process and draw using GLES2.0. Since then I was able to improve update from 9ms down to about 7ms, but I would like to ask if I would benefit from multi threading the update? As I understand from that diagram is that the function that takes the most time is the one you see it's color on the timeline. So the pink area is taken mostly by update. The other area has MainOpenGL.Handle as it's main contributor(whch is my java function), but since it's not drawn to the top of the diagram I can conclude other things are happening at the same time that use the CPU? Or even GPU stuff that isn't shown in this diagram. I am not sure how the GPU works on this. Does it calculate stuff in parallel to the CPU? Or is it part of the CPU usage as in SoC? I am not sure. Anyway, in case GPU things DO happen in parallel to CPU, then I would guess that if I do this C++ Update in parallel to the thread that makes the OpenGL calls, I might make use of "dead CPU time" due to GPU stalling or maybe have the GPU calls getting processed earlier because it won't have to wait for Update to finish? How do you suggest to improve performance based on that? Thanks.

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• Binding in the view or the controller?

  - by da_b0uncer

  I've seen 2 different approaches with MVC on the web. One, like in ExtJS, is to bind the callbacks to the view via the controller. Finding every element on the view and adding the functionallity. The other, like in angular.js and in the lift-framework server-side, too, is to bind in the views and just write the functionallity in the controller. Which is better and cleaner? The ExtJS approach has dumb views and all the logic in the controller. Which seems clean to me. I had problems with global IDs for GUI-elements or relative navigation to GUI-elements in this approach. When I changed the view, the controller couldn't find the buttons anymore or I had multiple instances of one button with the same ID on a single application, because of the global ID. But I solved this with IDs that are only global in a view and can be on the application multiple times. So I could mess with the (dumb) views layout and design and the functionallity wouldn't break. The angular.js approach with the bindings in the view don't has the problem with global IDs. Also, the person who changes something in the view layout has to know the IDs anyway, so the controller can put the data at the right spot. So if I write <a ng-click="doThis()" /> for angular.js and implement doThis() or <a lid="buttonwhichdoesthis" /> for extjs and find the element with the local id and add doThis() as handler on the controller side, seems to be not so different. The only thing is, the second one has one more layer of indirection, which seems cleaner. The first one seems somehow to cost less effort.

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• Designing a system with different business rules for different customers

  - by user1595846

  My company is rewriting our proprietary business application. The current architecture is poorly done and inflexible. It is coded more procedural oriented as opposed to object oriented. It has become difficult to maintain. Our system is a web application written in .Net Webforms. I am considering ASP.Net MVC for the rewrite. We intend to rewrite it with a good, solid architecture with the goal of maintainability and reusable classes for some of our other systems and services. We would also like the system to be customizable for different customers in the event that we market the system. I am considering redesigning the system based on the layered architecture (Presentation, Business, Data Access layers) described in the Microsoft Patterns and Practices Application Architecture Guide. http://msdn.microsoft.com/en-us/library/ff650706.aspx Hopefully this isn't too open ended, but how would you recommend allowing for different business logic/rules for different customers? I'm aware of Windows Workflow Foundation, but from what I've read about it, it seems many business rules could be too complicated to handle there. Also, Can anyone point me to where I can download an example of a .net solution that is based on the Application Architecture Guide? I have already downloaded the Layered Architecture Solution Guidance and the Expense Sample on codeplex. I was looking for something a bit larger and more robust that I could step through the code and see how it works. If you feel there are better architectures to base our redesign on please feel free to share. I appreciate your help!

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• How to choose between Tell don't Ask and Command Query Separation?

  - by Dakotah North

  The principle Tell Don't Ask says: you should endeavor to tell objects what you want them to do; do not ask them questions about their state, make a decision, and then tell them what to do. The problem is that, as the caller, you should not be making decisions based on the state of the called object that result in you then changing the state of the object. The logic you are implementing is probably the called object’s responsibility, not yours. For you to make decisions outside the object violates its encapsulation. A simple example of "Tell, don't Ask" is Widget w = ...; if (w.getParent() != null) { Panel parent = w.getParent(); parent.remove(w); } and the tell version is ... Widget w = ...; w.removeFromParent(); But what if I need to know the result from the removeFromParent method? My first reaction was just to change the removeFromParent to return a boolean denoting if the parent was removed or not. But then I came across Command Query Separation Pattern which says NOT to do this. It states that every method should either be a command that performs an action, or a query that returns data to the caller, but not both. In other words, asking a question should not change the answer. More formally, methods should return a value only if they are referentially transparent and hence possess no side effects. Are these two really at odds with each other and how do I choose between the two? Do I go with the Pragmatic Programmer or Bertrand Meyer on this?

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• Integrating Amazon EC2 in Java via NetBeans IDE

  - by Geertjan

  Next, having looked at Amazon Associates services and Amazon S3, let's take a look at Amazon EC2, the elastic compute cloud which provides remote computing services. I started by launching an instance of Ubuntu Server 14.04 on Amazon EC2, which looks a bit like this in the on-line AWS Management Console, though I whitened out most of the details: Now that I have at least one running instance available on Amazon EC2, it makes sense to use the services that are integrated into NetBeans IDE:  I created a new application with one class, named "AmazonEC2Demo". Then I dragged the "describeInstances" service that you see above, with the mouse, into the class. Then the IDE automatically created all the other files you see below, i.e., 4 Java classes and one properties file: In the properties file, register the access ID and secret keys. These are read by the other generated Java classes. Signing and authentication are done automatically by the code that is generated, i.e., there's nothing generic you need to do and you can immediately begin working on your domain-specific code. Finally, you're now able to rewrite the code in "AmazonEC2Demo" to connect to Amazon EC2 and obtain information about your running instance: public class AmazonEC2Demo { public static void main(String[] args) { String instanceId1 = "i-something"; RestResponse result; try { result = AmazonEC2Service.describeInstances(instanceId1); System.out.println(result.getDataAsString()); } catch (IOException ex) { Logger.getLogger(AmazonEC2Demo.class.getName()).log(Level.SEVERE, null, ex); } } } From the above, you'll receive a chunk of XML with data about the running instance, it's name, status, dates, etc. In other words, you're now ready to integrate Amazon EC2 features directly into the applications you're writing, without very much work to get started. Within about 5 minutes, you're working on your business logic, rather than on the generic code that anyone needs when integrating with Amazon EC2.

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• MVC pattern synchronisation

  - by Hariprasad

  I am facing a problem in synchronizing my model and view threads I have a view which is table. In it, user can select a few rows. I update the view as soon as the user clicks on any row since I don't want the UI to be slow. This updating is done by a logic which runs in the controller thread below. At the same time, the controller will update the model data too, which takes place in a different thread. i.e., controller puts the query in a queue, which is then executed by the model thread - which is a single-threaded interface. As soon as the query executes, controller will get a signal. Now, In order to keep the view and model synchronized, I will update the view again based on the return value of the query (the data returned by model) - even though I updated the view already for that user action. But, I am facing issues because, its taking a lot of time for the model to return the result, by that time user would have performed multiple clicks. So, as a result of updating the view again based on the information from model, the view sometimes goes back to the state in which the previous clicks were made (Suppose user clicks thrice on different rows. I update the view as soon as the click happens. Also, I update the view when I get data back from the model - which is supposed to be same as the already updated state of the view. Now, when the user clicks third time, I get data for the first click from model. As a result, view goes back to a state which is generated by the first click) Is there any way to handle such a synchronization issue?

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• Do the benefits of Resin/Quercus outweigh the overhead?

  - by Craige

  Lately, I've been looking more and more into Resin + Quercus as a technology to develop an application of mine. The reason I started looking into it was that this application has high reporting needs, a lot of which cannot (or realistically, should not) be created in real-time. Java would offer a nice backend to queue and generate reports. Also, with Quercus I would be able to develop my data models in Hibernate, and use them "from PHP", thus effectively stretching these models across front and back-end. This same concept would also apply to any front/back-end common business logic, which could be developed in Java libraries. Now, the downside is that whichever front-end (PHP) MVC Framework I choose (my goal was Symfony 2), it is unlikely to work without some heavy modification, if it can work at all. Quercus is a pretty close implementation of PHP, and is supposed to be compatible with PHP5.3, so namespaces and closures SHOULDN'T be a problem, but when I tried to run an existing Symfony 1.4 app, I failed miserably. So, my question to you is, do you think the benefits of Resin + Quercus outweigh the overhead of using a not-so-perfect/stable implementation of PHP? If this were your application, and your goal was and end-product, rather than educational purposes, what would you decide?

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• Question on methods in Object Oriented Programming

  - by mal

  I’m learning Java at the minute (first language), and as a project I’m looking at developing a simple puzzle game. My question relates to the methods within a class. I have my Block type class; it has its many attributes, set methods, get methods and just plain methods. There are quite a few. Then I have my main board class. At the moment it does most of the logic, positioning of sprites collision detection and then draws the sprites etc... As I am learning to program as much as I’m learning to program games I’m curious to know how much code is typically acceptable within a given method. Is there such thing as having too many methods? All my draw functionality happens in one method, should I break this into a few ‘sub’ methods? My thinking is if I find at a later stage that the for loop I’m using to cycle through the array of sprites searching for collisions in the spriteCollision() method is inefficient I code a new method and just replace the old method calls with the new one, leaving the old code intact. Is it bad practice to have a method that contains one if statement, and place the call for that method in the for loop? I’m very much in the early stages of coding/designing and I need all the help I can get! I find it a little intimidating when people are talking about throwing together a prototype in a day too! Can’t wait until I’m that good!

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