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• Where to start with game development?

  - by steven_desu

  I asked this earlier in this thread at stackoverflow.com. One of the early comments redirected me here to gamedev.stackexchange.com, so I'm reposting here. Searching for related questions I found a number of very specific questions, but I'm afraid the specifics have proved fruitless for me and after 4 hours on Google I'm no closer than I started, so I felt reaching out to a community might be in order. First, my goal: I've never made a game before, although I've muddled over the possibility several times. I decided to finally sit down and start learning how to code games, use game engines, etc. All so that one day (hopefully soon) I'll be able to make functional (albeit simple) games. I can start adding complexity later, for now I'd be glad to have a keyboard-controlled camera moving in a 3D world with no interaction beyond that. My background: I've worked in SEVERAL programming languages ranging from PHP to C++ to Java to ASM. I'm not afraid of any challenges that come with learning the new syntax or limitations inherent in a new language. All of my past programming experience, however, has been strictly non-graphical and usually with little or extremely simple interaction during execution. I've created extensive and brilliant algorithms for solving logical and mathematical problems as well as graphing problems. However in every case input was either defined in a file, passed form an HTML form, or typed into the console. Real-time interaction with the user is something with which I have no experience. My question: Where should I start in trying to make games? Better yet- where should I start in trying to create a keyboard-navigable 3D environment? In searching online I've found several resources linking to game engines, graphics engines, and physics engines. Here's a brief summary of my experiences with a few engines I tried: Unreal SDK: The tutorial videos assume that you already have in-depth knowledge of 3D modeling, graphics engines, animations, etc. The "Getting Started" page offers no formal explanation of game development but jumps into how Unreal can streamline processes it assumes you're already familiar with. After downloading the SDK and launching it to see if the tools were as intuitive as they claimed, I was greeted with about 60 buttons and a blank void for my 3D modeling. Clicking on "add volume" (to attempt to add a basic cube) I was met with a menu of 30 options. Panicking, I closed the editor. Crystal Space: The website seemed rather informative, explaining that Crystal Space was just for graphics and the companion software, CEL, provided entity logic for making games. A demo game was provided, which was built using "CELStart", their simple tool for people with no knowledge of game programming. I launched the game to see what I might look forward to creating. It froze several times, the menus were buggy, there were thousands of graphical glitches, enemies didn't respond to damage, and when I closed the game it locked up. Gave up on that engine. IrrLicht: The tutorial assumes I have Visual Studio 6.0 (I have Visual Studio 2010). Following their instructions I was unable to properly import the library into Visual Studio and unable to call any of the functions that they kept using. Manually copying header files, class files, and DLLs into my project's folder - the project failed to properly compile. Clearly I'm not off to a good start and I'm going in circles. Can someone point me in the right direction? Should I start by downloading a program like Blender and learning 3D modeling, or should I be learning how to use a graphics engine? Should I look for an all-inclusive game engine, or is it better to try and code my own game logic? If anyone has actually made their own games, I would prefer to hear how they got their start. Also- taking classes at my school is not an option. Nothing is offered.

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• Where to start with game development?

  - by steven_desu

  Searching for related questions I found a number of very specific questions, but I'm afraid the specifics have proved fruitless for me and after 4 hours on Google I'm no closer than I started, so I felt reaching out to a community might be in order. First, my goal: I've never made a game before, although I've muddled over the possibility several times. I decided to finally sit down and start learning how to code games, use game engines, etc. All so that one day (hopefully soon) I'll be able to make functional (albeit simple) games. I can start adding complexity later, for now I'd be glad to have a keyboard-controlled camera moving in a 3D world with no interaction beyond that. My background: I've worked in SEVERAL programming languages ranging from PHP to C++ to Java to ASM. I'm not afraid of any challenges that come with learning the new syntax or limitations inherent in a new language. All of my past programming experience, however, has been strictly non-graphical and usually with little or extremely simple interaction during execution. I've created extensive and brilliant algorithms for solving logical and mathematical problems. However in every case input was either defined in a file, passed form an HTML form, or typed into the console. Real-time interaction with the user is something with which I have no experience. My question: Where should I start in trying to make games? Better yet- where should I start in trying to create a keyboard-navigable 3D environment? In searching online I've found several resources linking to game engines, graphics engines, and physics engines. Here's a brief summary of my experiences with a few engines I tried: Unreal SDK: The tutorial videos assume that you already have in-depth knowledge of 3D modeling, graphics engines, animations, etc. The "Getting Started" page offers no formal explanation of game development but jumps into how Unreal can streamline processes it assumes you're already familiar with. After downloading the SDK and launching it to see if the tools were as intuitive as they claimed, I was greeted with about 60 buttons and a blank void for my 3D modeling. Clicking on "add volume" (to attempt to add a basic cube) I was met with a menu of 30 options. Panicking, I closed the editor. Crystal Space: The website seemed rather informative, explaining that Crystal Space was just for graphics and the companion software, CEL, provided entity logic for making games. A demo game was provided, which was built using "CELStart", their simple tool for people with no knowledge of game programming. I launched the game to see what I might look forward to creating. It froze several times, the menus were buggy, there were thousands of graphical glitches, enemies didn't respond to damage, and when I closed the game it locked up. Gave up on that engine. IrrLicht: The tutorial assumes I have Visual Studio 6.0 (I have Visual Studio 2010). Following their instructions I was unable to properly import the library into Visual Studio and unable to call any of the functions that they kept using. Manually copying header files, class files, and DLLs into my project's folder - the project failed to properly compile. Clearly I'm not off to a good start and I'm going in circles. Can someone point me in the right direction? Should I start by downloading a program like Blender and learning 3D modeling, or should I be learning how to use a graphics engine? Should I look for an all-inclusive game engine, or is it better to try and code my own game logic? If anyone has actually made their own games, I would prefer to hear how they got their start. Also- taking classes at my school is not an option. Nothing is offered.

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• Python Coding standards vs. productivity

  - by Shroatmeister

  I work for a large humanitarian organisation, on a project building software that could help save lives in emergencies by speeding up the distribution of food. Many NGOs desperately need our software and we are weeks behind schedule. One thing that worries me in this project is what I think is an excessive focus on coding standards. We write in python/django and use a version of PEP0008, with various modifications e.g. line lengths can go up to 160 chars and all lines should go that long if possible, no blank lines between imports, line wrapping rules that apply only to certain kinds of classes, lots of templates that we must use, even if they aren't the best way to solve a problem etc. etc. One core dev spent a week rewriting a major part of the system to meet the then new coding standards, throwing away several suites of tests in the process, as the rewrite meant they were 'invalid'. We spent two weeks rewriting all the functionality that was lost, and fixing bugs. He is the lead dev and his word carries weight, so he has convinced the project manager that these standards are necessary. The junior devs do as they are told. I sense that the project manager has a strong feeling of cognitive dissonance about all this but nevertheless agrees with it vehemently as he feels unsure what else to do. Today I got in serious trouble because I had forgotten to put some spaces after commas in a keyword argument. I was literally shouted at by two other devs and the project manager during a Skype call. Personally I think coding standards are important but also think that we are wasting a lot of time obsessing with them, and when I verbalized this it provoked rage. I'm seen as a troublemaker in the team, a team that is looking for scapegoats for its failings. Since the introduction of the coding standards, the team's productivity has measurably plummeted, however this only reinforces the obsession, i.e. the lead dev simply blames our non-adherence to standards for the lack of progress. He believes that we can't read each other's code if we don't adhere to the conventions. This is starting to turn sticky. Now I am trying to modify various scripts, autopep8, pep8ify and PythonTidy to try to match the conventions. We also run pep8 against source code but there are so many implicit amendments to our standard that it's hard to track them all. The lead dev simple picks faults that the pep8 script doesn't pick up and shouts at us in the next stand-up meeting. Every week there are new additions to the coding standards that force us to rewrite existing, working, tested code. Thank heavens we still have tests, (I reverted some commits and fixed a bunch of the ones he removed). All the while there is increasing pressure to meet the deadline. I believe a fundamental issue is that the lead dev and another core dev refuse to trust other developers to do their job. But how to deal with that? We can't do our job because we are too busy rewriting everything. I've never encountered this dynamic in a software engineering team. Am I wrong to question their adherence to coding standards? Has anyone else experienced a similar situation and how have they dealt with it successfully? (I'm not looking for a discussion just actual solutions people have found)

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• Adding custom interfaces to your mock instance.

  - by mehfuzh

  Previously, i made a post  showing how you can leverage the dependent interfaces that is implemented by JustMock during the creation of mock instance. It could be a informative post that let you understand how JustMock behaves internally for class or interfaces implement other interfaces into it. But the question remains, how you can add your own custom interface to your target mock. In this post, i am going to show you just that. Today, i will not start with a dummy class as usual rather i will use two most common interfaces in the .NET framework  and create a mock combining those. Before, i start i would like to point out that in the recent release of JustMock we have extended the Mock.Create<T>(..) with support for additional settings though closure. You can add your own custom interfaces , specify directly the real constructor that should be called or even set the behavior of your target. Doing a fast forward directly to the point,  here goes the test code for create a creating a mock that contains the mix for ICloneable and IDisposable using the above mentioned changeset. var myMock = Mock.Create<IDisposable>(x => x.Implements<ICloneable>()); var myMockAsClonable = myMock as ICloneable; bool isCloned = false;   Mock.Arrange(() => myMockAsClonable.Clone()).DoInstead(() => isCloned = true);   myMockAsClonable.Clone();   Assert.True(isCloned);   Here, we are creating the target mock for IDisposable and also implementing ICloneable. Finally, using the “as” for getting the ICloneable reference accordingly arranging it, acting on it and asserting if the expectation is met properly. This is a very rudimentary example, you can do the same for a given class: var realItem = Mock.Create<RealItem>(x => {     x.Implements<IDisposable>();     x.CallConstructor(() => new RealItem(0)); }); var iDispose = realItem as IDisposable;     iDispose.Dispose(); Here, i am also calling the real constructor for RealItem class.  This is to mention that you can implement custom interfaces only for non-sealed classes or less it will end up with a proper exception. Also, this feature don’t require any profiler, if you are agile or running it inside silverlight runtime feel free to try it turning off the JM add-in :-). TIP :  Ability to  specify real constructor could be a useful productivity boost in cases for code change and you can re-factor the usage just by one click with your favorite re-factor tool.   That’s it for now and hope that helps Enjoy!!

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• Duke's Choice Award Ceremony

  - by Tori Wieldt

  The 2012 Duke's Choice Awards winners and their creative, Java-based technologies and Java community contributions were honored after the Sunday night JavaOne keynotes. Sharat Chander, Group Director for Java Technology Outreach, presented the awards. "Having the community participate directly in both submission and selection truly shows how we are driving exposure of the innovation happening in the Java community," he said. Apache Software Foundation Hadoop Project The Apache Software Foundation’s Hadoop project, written in Java, provides a framework for distributed processing of big data sets across clusters of computers, ranging from a few servers to thousands of machines. This harnessing of large data pools allows organizations to better understand and improve their business. AgroSense Project Improving farming methods to feed a hungry world is the goal of AgroSense, an open source farm information management system built in Java and the NetBeans platform. AgroSense enables farmers, agribusinesses, suppliers and others to develop modular applications that will easily exchange information through a common underlying NetBeans framework. JDuchess Rather than focus on a specific geographic area like most Java User Groups (JUGs), JDuchess fosters the participation of women in the Java community worldwide. The group has more than 500 members in 60 countries, and provides a platform through which women can connect with each other and get involved in all aspects of the Java community. Jelastic, Inc. Moving existing Java applications to the cloud can be a daunting task, but startup Jelastic, Inc. offers the first all-Java platform-as-a-service (PaaS) that enables existing Java applications to be deployed in the cloud without code changes or lock-in. Liquid Robotics Robotics – Liquid Robotics is an ocean data services provider whose Wave Glider technology collects information from the world’s oceans for application in government, science and commercial applications. The organization features the “father of Java” James Gosling as its chief software architect. London Java Community The second user group receiving a Duke’s Choice Award this year, the London Java Community (LJC) and its users have been active in the OpenJDK, the Java Community Process (JCP) and other efforts within the global Java community. NATO The first-ever Community Choice Award goes to the MASE Integrated Console Environment (MICE) in use at NATO. Built in Java on the NetBeans platform, MICE provides a high-performance visualization environment for conducting air defense and battle-space operations. Parleys.com E-learning specialist Parleys.com, based in Brussels, Belgium, uses Java technologies to bring online classes and full IT conferences to desktops, laptops, tablets and mobile devices. Parleys.com has hosted more than 1,700 conferences—including Devoxx and JavaOne—for more than 800,000 unique visitors. Student Nokia Developer Group This year’s student winner, Ram Kashyap, is the founder and president of the Nokia Student Network, and was profiled in the “The New Java Developers” feature in the March/April 2012 issue of Java Magazine. Since then, Ram has maintained a hectic pace, graduating from the People’s Education Society Institute of Technology in Bangalore, India, while working on a Java mobile startup and training students on Java ME. United Nations High Commissioner for Refugees The United Nations High Commissioner for Refugees (UNHCR) is on the front lines of crises around the world, from civil wars to natural disasters. To help facilitate its mission of humanitarian relief, the UNHCR has developed a light-client Java application on the NetBeans platform. The Level One registration tool enables the UNHCR to collect information on the number of refugees and their water, food, housing, health, and other needs in the field, and combines that with geocoding information from various sources. This enables the UNHCR to deliver the appropriate kind and amount of assistance where it is needed. You can read more about the winners in the current issue of Java Magazine.

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• Dark Sun Dispatch 001

  - by Chris Williams

  If you aren't into tabletop (aka pen & paper) RPGs, you might as well click to the next post now... Still here? Awesome. I've recently started running a new D&D 4.0 Dark Sun campaign. If you don't know anything about Dark Sun, here's a quick intro: The campaign take place on the world of Athas, formerly a lush green world that is now a desert wasteland. Forests are rare in the extreme, as is water and metal. Coins are made of ceramic and weapons are often made of hardened wood, bone or obsidian. The green age of Athas was centuries ago and the current state was brought about through the reckless use of sorcerous magic. (In this world, you can augment spells by drawing on the life force of the world & people around you. This is called defiling. Preserving magic draws upon the casters life force and does not damage the surrounding world, but it isn't as powerful.) Humans are pretty much unchanged, but the traditional fantasy races have changed quite a bit. Elves don't live in the forest, they are shifty and untrustworthy desert traders known for their ability to run long distances through the wastes. Halflings are not short, fat, pleasant little riverside people. Instead they are bloodthirsty feral cannibals that roam the few remaining forests and ride reptilians beasts akin to raptors. Gnomes are extinct, as are orcs. Dwarves are mostly farmers and gladiators, and live out in the sun instead of staying under the mountains. Goliaths are half-giants, not known for their intellect. Muls are a Dwarf & Human crossbreed that displays the best traits of both races (human height and dwarven stoutness.) Thri-Kreen are sentient mantis people that are extremely fast. Most of the same character classes are available, with a few new twists. There are no divine characters (such as Priests, Paladins, etc) because the gods are gone. Nobody alive today can remember a time when they were still around. Instead, some folks worship the elemental forces (although they don't give out spells.) The cities are all ruled by Sorcerer King tyrants (except one city: Tyr) who are hundreds of years old and still practice defiling magic whenever they please. Serving the Sorcerer Kings are the Templars, who are also defilers and psionicists. Crossing them is as bad, in many cases, as crossing the Kings themselves. Between the cities you have small towns and trading outposts, and mostly barren desert with sometimes 4-5 days on foot between towns and the nearest oasis. Being caught out in the desert without adequate supplies and protection from the elements is pretty much a death sentence for even the toughest heroes. When you add in the natural (and unnatural) predators that roam the wastes, often in packs, most people don't last long alone. In this campaign, the adventure begins in the (small) trading fortress of Altaruk, a couple weeks walking distance from the newly freed city of Tyr. A caravan carrying trade goods from Altaruk has not made it to Tyr and the local merchant house has dispatched the heroes to find out what happened and to retrieve the goods (and drivers) if possible. The unlikely heroes consist of a human shaman, a thri-kreen monk, a human wizard, a kenku assassin and a (void aspect) genasi swordmage. Gathering up supplies and a little liquid courage, they set out into the desert and manage to find the northbound tracks of the wagon. Shortly after finding the tracks, they are ambushed by a pack of silt-runners (small lizard people with very large teeth and poisoned pointy spears.) The party makes short work of the creatures, taking a few minor wounds in the process. Proceeding onward without resting, they find the remains of the wagon and manage to sneak up on a pack of Kruthiks picking through the rubble and spilled goods. Unfortunately, they failed to take advantage of the opportunity and had a hard fight ahead of them. The party defeated the kruthiks, but took heavy damage (and almost lost a couple of their own) in the process. Once the kruthiks were dispatched, they followed a set of tracks further north to a ruined tower...

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• HTTP Module in detail

  - by Jalpesh P. Vadgama

  I know this post may sound like very beginner level. But I have already posted two topics regarding HTTP Handler and HTTP module and this will explain how http module works in the system. I have already posted What is the difference between HttpModule and HTTPHandler here. Same way I have posted about an HTTP Handler example here as people are still confused with it. In this post I am going to explain about HTTP Module in detail. What is HTTP Module As we all know that when ASP.NET Runtimes receives any request it will execute a series of HTTP Pipeline extensible objects. HTTP Module and HTTP handler play important role in extending this HTTP Pipelines. HTTP Module are classes that will pre and post process request as they pass into HTTP Pipelines.  So It’s one kind of filter we can say which will do some procession on begin request and end request. If we have to create HTTP Module we have to implement System.Web.IHttpModule interface in our custom class. An IHTTP Module contains two method dispose where you can write your clean up code and another is Init where your can write your custom code to handle request. Here you can your event handler that will execute at the time of begin request and end request. Let’s create an HTTP Module which will just print text in browser with every request. Here is the code for that. using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace Experiment { public class MyHttpModule:IHttpModule { public void Dispose() { //add clean up code here if required } public void Init(HttpApplication context) { context.BeginRequest+=new EventHandler(context_BeginRequest); context.EndRequest+=new EventHandler(context_EndRequest); } public void context_BeginRequest(object o, EventArgs args) { HttpApplication app = (HttpApplication)o; if (app != null) { app.Response.Write("<h1>Begin Request Executed</h1>"); } } public void context_EndRequest(object o, EventArgs args) { HttpApplication app = (HttpApplication)o; if (app != null) { app.Response.Write("<h1>End Request Executed</h1>"); } } } } Here in above code you can see that I have created two event handler context_Beginrequest and context_EndRequest which will execute at begin request and end request when request are processed. In this event handler I have just written a code to print text on browser. Now In order enable this HTTP Module in HTTP pipeline we have to put a settings in web.config  HTTPModules section to tell which HTTPModule is enabled. Below is code for HTTPModule. <configuration> <system.web> <compilation debug="true" targetFramework="4.0" /> <httpModules> <add name="MyHttpModule" type="Experiment.MyHttpModule,Experiment"/> </httpModules> </system.web> </configuration> Now I just have created a sample webform with following code in HTML like following. <form id="form1" runat="server"> <B>test of HTTP Module</B> </form> Now let’s run this web form in browser and you can see here it the output as expected.   Technorati Tags: HTTPModule,ASP.NET,Request

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• How should an object that uses composition set its composed components?

  - by Casey

  After struggling with various problems and reading up on component-based systems and reading Bob Nystrom's excellent book "Game Programming Patterns" and in particular the chapter on Components I determined that this is a horrible idea: //Class intended to be inherited by all objects. Engine uses Objects exclusively. class Object : public IUpdatable, public IDrawable { public: Object(); Object(const Object& other); Object& operator=(const Object& rhs); virtual ~Object() =0; virtual void SetBody(const RigidBodyDef& body); virtual const RigidBody* GetBody() const; virtual RigidBody* GetBody(); //Inherited from IUpdatable virtual void Update(double deltaTime); //Inherited from IDrawable virtual void Draw(BITMAP* dest); protected: private: }; I'm attempting to refactor it into a more manageable system. Mr. Nystrom uses the constructor to set the individual components; CHANGING these components at run-time is impossible. It's intended to be derived and be used in derivative classes or factory methods where their constructors do not change at run-time. i.e. his Bjorne object is just a call to a factory method with a specific call to the GameObject constructor. Is this a good idea? Should the object have a default constructor and setters to facilitate run-time changes or no default constructor without setters and instead use a factory method? Given: class Object { public: //...See below for constructor implementation concerns. Object(const Object& other); Object& operator=(const Object& rhs); virtual ~Object() =0; //See below for Setter concerns IUpdatable* GetUpdater(); IDrawable* GetRenderer(); protected: IUpdatable* _updater; IDrawable* _renderer; private: }; Should the components be read-only and passed in to the constructor via: class Object { public: //No default constructor. Object(IUpdatable* updater, IDrawable* renderer); //...remainder is same as above... }; or Should a default constructor be provided and then the components can be set at run-time? class Object { public: Object(); //... SetUpdater(IUpdater* updater); SetRenderer(IDrawable* renderer); //...remainder is same as above... }; or both? class Object { public: Object(); Object(IUpdater* updater, IDrawable* renderer); //... SetUpdater(IUpdater* updater); SetRenderer(IDrawable* renderer); //...remainder is same as above... };

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• Lessons Building KeyRef (a .NET developer learning Rails)

  - by Liam McLennan

  Just because I like to build things, and I like to learn, I have been working on a keyboard shortcut reference site. I am using this as an opportunity to improve my ruby and rails skills. The first few days were frustrating. Perhaps the learning curve of all the fun new toys was a bit excessive. Finally tonight things have really started to come together. I still don’t understand the rails built-in testing support but I will get there. Interesting Things I Learned Tonight RubyMine IDE Tonight I switched to RubyMine instead of my usual Notepad++. I suspect RubyMine is a powerful tool if you know how to use it – but I don’t. At the moment it gives me errors about some gems not being activated. This is another one of those things that I will get to. I have also noticed that the editor functions significantly differently to the editors I am used to. For example, in visual studio and notepad++ if you place the cursor at the start of a line and press left arrow the cursor is sent to the end of the previous line. In RubyMine nothing happens. Haml Haml is my favourite view engine. For my .NET work I have been using its non-union Mexican CLR equivalent – nHaml. Multiple CSS Classes To define a div with more than one css class haml lets you chain them together with a ‘.’, such as: .span-6.search_result contents of the div go here Indent Consistency I also learnt tonight that both haml and nhaml complain if you are not consistent about indenting. As a consequence of the move from notepad++ to RubyMine my haml views ended up with some tab indenting and some space indenting. For the view to render all of the indents within a view must be consistent. Sorting Arrays I guessed that ruby would be able to sort an array alphabetically by a property of the elements so my first attempt was: Application.all.sort {|app| app.name} which does not work. You have to supply a comparer (much like .NET). The correct sort is: Application.all.sort {|a,b| a.name.downcase <=> b.name.downcase} MongoMapper Find by Id Since document databases are just fancy key-value stores it is essential to be able to easily search for a document by its id. This functionality is so intrinsic that it seems that the MongoMapper author did not bother to document it. To search by id simply pass the id to the find method: Application.find(‘4c19e8facfbfb01794000002’) Rails And CoffeeScript I am a big fan of CoffeeScript so integrating it into this application is high on my priorities. My first thought was to copy Dr Nic’s strategy. Unfortunately, I did not get past step 1. Install Node.js. I am doing my development on Windows and node is unix only. I looked around for a solution but eventually had to concede defeat… for now. Quicksearch The front page of the application I am building displays a list of applications. When the user types in the search box I want to reduce the list of applications to match their search. A quick googlebing turned up quicksearch, a jquery plugin. You simply tell quicksearch where to get its input (the search textbox) and the list of items to filter (the divs containing the names of applications) and it just works. Here is the code: $('#app_search').quicksearch('.search_result'); Summary I have had a productive evening. The app now displays a list of applications, allows them to be sorted and links through to an application page when an application is selected. Next on the list is to display the set of keyboard shortcuts for an application.

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• When to use Aspect Oriented Architecture (AOA/AOD)

  When is it appropriate to use aspect oriented architecture? I think the only honest answer to this question is that it depends on the context for which the question is being asked. There really are no hard and fast rules regarding the selection of an architectural model(s) for a project because each model provides good and bad benefits. Every system is built with a unique requirements and constraints. This context will dictate when to use one type of architecture over another or in conjunction with others. To me aspect oriented architecture models should be a sub-phase in the architectural modeling and design process especially when creating enterprise level models. Personally, I like to use this approach to create a base architectural model that is defined by non-functional requirements and system quality attributes.   This general model can then be used as a starting point for additional models because it is targets all of the business key quality attributes required by the system.Aspect oriented architecture is a method for modeling non-functional requirements and quality attributes of a system known as aspects. These models do not deal directly with specific functionality. They do categorize functionality of the system. This approach allows a system to be created with a strong emphasis on separating system concerns into individual components. These cross cutting components enables a systems to create with compartmentalization in regards to non-functional requirements or quality attributes.  This allows for the reduction in code because an each component maintains an aspect of a system that can be called by other aspects. This approach also allows for a much cleaner and smaller code base during the implementation and support of a system. Additionally, enabling developers to develop systems based on aspect-oriented design projects will be completed faster and will be more reliable because existing components can be shared across a system; thus, the time needed to create and test the functionality is reduced.   Example of an effective use of Aspect Oriented ArchitectureIn my experiences, aspect oriented architecture can be very effective with large or more complex systems. Typically, these types of systems have a large number of concerns so the act of defining them is very beneficial for reducing the system’s complexity because components can be developed to address each concern while exposing functionality to the other system components. The benefits to using the aspect oriented approach as the starting point for a system is that it promotes communication between IT and the business due to the fact that the aspect oriented models are quality attributes focused so not much technical understanding is needed to understand the model.An example of this can be in developing a new intranet website. Common Intranet Concerns: Error Handling Security Logging Notifications Database connectivity Example of a not as effective use of Aspect Oriented ArchitectureAgain in my experiences, aspect oriented architecture is not as effective with small or less complex systems in comparison.  There is no need to model concerns for a system that has a limited amount of them because the added overhead would not be justified for the actual benefits of creating the aspect oriented architecture model.  Furthermore, these types of projects typically have a reduced time schedule and a limited budget.  The creation of the Aspect oriented models would increase the overhead of a project and thus increase the time needed to implement the system. An example of this is seen by creating a small application to poll a network share for new files and then FTP them to a new location.  The two primary concerns for this project is to monitor a network drive and FTP files to a new location.  There is no need to create an aspect model for this system because there will never be a need to share functionality amongst either of these concerns.  To add to my point, this system is so small that it could be created with just a few classes so the added layer of componentizing the concerns would be complete overkill for this situation. References:Brichau, Johan; D'Hondt, Theo. (2006) Aspect-Oriented Software Development (AOSD) - An Introduction. Retreived from: http://www.info.ucl.ac.be/~jbrichau/courses/introductionToAOSD.pdf

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• Do you want to be an ALM Consultant?

  - by Martin Hinshelwood

  Northwest Cadence is looking for our next great consultant! At Northwest Cadence, we have created a work environment that emphasizes excellence, integrity, and out-of-the-box thinking.  Our customers have high expectations (rightfully so) and we wouldn’t have it any other way!   Northwest Cadence has some of the most exciting customers I have ever worked with and even though I have only been here just over a month I have already: Provided training/consulting for 3 government departments Created and taught courseware for delivering Scrum to teams within a high profile multinational company Started presenting Microsoft's ALM Engagement Program  So if you are interested in helping companies build better software more efficiently, then.. Enquire at [email protected] Application Lifecycle Management (ALM) Consultant An ALM Consultant with a minimum of 8 years of relevant experience with Application Lifecycle Management, Visual Studio (including Visual Studio Team System) and software design is needed. Must provide thought leadership on best practices for enterprise architecture, understand the Microsoft technology solution stack, and have a thorough understanding of enterprise application integration. The ALM Practice Lead will play a central role in designing and implementing the overall ALM Practice strategy, including creating, updating, and delivering ALM courseware and consultancy engagements. This person will also provide project support, deliverables, and quality solutions on Visual Studio Team System that exceed client expectations. Engagements will vary and will involve providing expert training, consulting, mentoring, formulating technical strategies and policies and acting as a “trusted advisor” to customers and internal teams. Sound sense of business and technical strategy required. Strong interpersonal skills as well as solid strategic thinking are key. The ideal candidate will be capable of envisioning the solution based on the early client requirements, communicating the vision to both technical and business stakeholders, leading teams through implementation, as well as training, mentoring, and hands-on software development. The ideal candidate will demonstrate successful use of both agile and formal software development methods, enterprise application patterns, and effective leadership on prior projects. Job Requirements Minimum Education: Bachelor’s Degree (computer science, engineering, or math preferred). Locale / Travel: The Practice Lead position requires estimated 50% travel, most of which will be in the Continental US (a valid national Passport must be maintained).  This is a full time position and will be based in the Kirkland office. Preferred Education: Master’s Degree in Information Technology or Software Engineering; Premium Microsoft Certifications on .NET (MCSD) or MCPD or relevant experience; Microsoft Certified Trainer (MCT) or relevant experience. Minimum Experience and Skills: 7+ years experience with business information systems integration or custom business application design and development in a professional technology consulting, corporate MIS or software development environment. Essential Duties & Responsibilities: Provide training, consulting, and mentoring to organizations on topics that include Visual Studio Team System and ALM. Create content, including labs and demonstrations, to be delivered as training classes by Northwest Cadence employees. Lead development teams through the complete ALM and/or Visual Studio Team System solution. Be able to communicate in detail how a solution will integrate into the larger technical problem space for large, complex enterprises. Define technical solution requirements. Provide guidance to the customer and project team with respect to technical feasibility, complexity, and level of effort required to deliver a custom solution. Ensure that the solution is designed, developed and deployed in accordance with the agreed upon development work plan. Create and deliver weekly status reports of training and/or consulting progress. Engagement Responsibilities: · Provide a strong desire to provide thought leadership related to technology and to help grow the business. · Work effectively and professionally with employees at all levels of a customer’s organization. · Have strong verbal and written communication skills. · Have effective presentation, organizational and planning skills. · Have effective interpersonal skills and ability to work in a team environment. Enquire at [email protected]

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• Tuning Default WorkManager - Advantages and Disadvantages

  - by Murali Veligeti

  Before discussing on Tuning Default WorkManager, lets have a brief introduction on What is Default WorkManger Before Weblogic Server 9.0 release, we had the concept of Execute Queues. WebLogic Server (before WLS 9.0), processing was performed in multiple execute queues. Different classes of work were executed in different queues, based on priority and ordering requirements, and to avoid deadlocks. In addition to the default execute queue, weblogic.kernel.default, there were pre-configured queues dedicated to internal administrative traffic, such as weblogic.admin.HTTP and weblogic.admin.RMI.Users could control thread usage by altering the number of threads in the default queue, or configure custom execute queues to ensure that particular applications had access to a fixed number of execute threads, regardless of overall system load. From WLS 9.0 release onwards WebLogic Server uses is a single thread pool (single thread pool which is called Default WorkManager), in which all types of work are executed. WebLogic Server prioritizes work based on rules you define, and run-time metrics, including the actual time it takes to execute a request and the rate at which requests are entering and leaving the pool.The common thread pool changes its size automatically to maximize throughput. The queue monitors throughput over time and based on history, determines whether to adjust the thread count. For example, if historical throughput statistics indicate that a higher thread count increased throughput, WebLogic increases the thread count. Similarly, if statistics indicate that fewer threads did not reduce throughput, WebLogic decreases the thread count. This new strategy makes it easier for administrators to allocate processing resources and manage performance, avoiding the effort and complexity involved in configuring, monitoring, and tuning custom executes queues. The Default WorkManager is used to handle thread management and perform self-tuning.This Work Manager is used by an application when no other Work Managers are specified in the application’s deployment descriptors. In many situations, the default Work Manager may be sufficient for most application requirements. WebLogic Server’s thread-handling algorithms assign each application its own fair share by default. Applications are given equal priority for threads and are prevented from monopolizing them. The default work-manager, as its name tells, is the work-manager defined by default.Thus, all applications deployed on WLS will use it. But sometimes, when your application is already in production, it's obvious you can't take your EAR / WAR, update the deployment descriptor(s) and redeploy it.The default work-manager belongs to a thread-pool, as initial thread-pool comes with only five threads, that's not much. If your application has to face a large number of hits, you may want to start with more than that.Well, that's quite easy. You have  two option to do so.1) Modify the config.xmlJust add the following line(s) in your server definition : <server> <name>AdminServer</name> <self-tuning-thread-pool-size-min>100</self-tuning-thread-pool-size-min> <self-tuning-thread-pool-size-max>200</self-tuning-thread-pool-size-max> [...] </server> 2) Adding some JVM parameters Add the following system property in setDomainEnv.sh/setDomainEnv.cmd or startWebLogic.sh/startWebLogic.cmd : -Dweblogic.threadpool.MinPoolSize=100 -Dweblogic.threadpool.MaxPoolSize=100 Reboot WLS and see the option has been taken into account . Disadvantage: So far its fine. But here there is an disadvantage in tuning Default WorkManager. Internally Weblogic Server has many work managers configured for different types of work.  if we run out of threads in the self-tuning pool(because of system property -Dweblogic.threadpool.MaxPoolSize) due to being undersized, then important work that WLS might need to do could be starved.  So, while limiting the self-tuning would limit the default WorkManager and internally it also limits all other internal WorkManagers which WLS uses.So the best alternative is to override the default WorkManager that means creating a WorkManager for the Application and assign the WorkManager for the application instead of tuning the Default WorkManager.

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• Requesting feedback on my OO design

  - by Prog

  I'm working on an application that creates music by itself. I'm seeking feedback for my OO design so far. This question will focus on one part of the program. The application produces Tune objects, that are the final musical products. Tune is an abstract class with an abstract method play. It has two subclasses: SimpleTune and StructuredTune. SimpleTune owns a Melody and a Progression (chord sequence). It's play implementation plays these two objects simultaneously. StructuredTune owns two Tune instances. It's own play plays the two Tunes one after the other according to a pattern (currently only ABAB). Melody is an abstract class with an abstract play method. It has two subclasses: SimpleMelody and StructuredMelody. SimpleMelody is composed of an array of notes. Invoking play on it plays these notes one after the other. StructuredMelody is composed of an array of Melody objects. Invoking play on it plays these Melodyies one after the other. I think you're starting to see the pattern. Progression is also an abstract class with a play method and two subclasses: SimpleProgression and StructuredProgression, each composed differently and played differently. SimpleProgression owns an array of chords and plays them sequentially. StructuredProgression owns an array of Progressions and it's play implementation plays them sequentially. Every class has a corresponding Generator class. Tune, Melody and Progression are matched with corresponding abstract TuneGenerator, MelodyGenerator and ProgressionGenerator classes, each with an abstract generate method. For example MelodyGenerator defines an abstract Melody generate method. Each of the generators has two subclasses, Simple and Structured. So for example MelodyGenerator has a subclasses SimpleMelodyGenerator, with an implementation of generate that returns a SimpleMelody. (It's important to note that the generate methods encapsulate complex algorithms. They are more than mere factory method. For example SimpleProgressionGenerator.generate() implements an algorithm to compose a series of Chord objects, which are used to instantiate the returned SimpleProgression). Every Structured generator uses another generator internally. It is a Simple generator be default, but in special cases may be a Structured generator. Parts of this design are meant to allow the end-user through the GUI to choose what kind of music is to be created. For example the user can choose between a "simple tune" (SimpleTuneGenerator) and a "full tune" (StructuredTuneGenerator). Other parts of the system aren't subject to direct user-control. What do you think of this design from an OOD perspective? What potential problems do you see with this design? Please share with me your criticism, I'm here to learn. Apart from this, a more specific question: the "every class has a corresponding Generator class" part feels very wrong. However I'm not sure how I could design this differently and achieve the same flexibility. Any ideas?

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• Tyrus 1.8

  - by Pavel Bucek

  Another version of Tyrus, the reference implementation of JSR 356 – Java API for WebSocket is out! Complete list of fixes and features is below, but let me describe some of the new features in more detail. All information presented here is also available in Tyrusdocumentation. What’s new? First to mention is that JSR 356 Maintenance review Ballot is over and the change proposed for 1.1 release was accepted. More details about changes in the API can be found in this article. Important part is that Tyrus 1.8 implements this API, meaning you can use Lambda expressions and some features of Nashorn without the need for any workarounds. Almost all other features are related to client side support, which was significantly improved in this release. Firstly – I have to admit, that Tyrus client contained security issue – SSL Hostname verification was not performed when connecting to “wss” endpoints. This was fixed as part of TYRUS-339 and resulted in some changes in the client configuration API. Now you can control whether HostnameVerification should be performed (SslEngineConfigurator#setHostnameVerificationEnabled(boolean)) or even set your own HostnameVerifier (please use carefully): #setHostnameVerifier(…). Detailed description can be found in Host verification chapter. Another related enhancement is support for Http Basic and Digest authentication schemes. Tyrus client now enables users to provide credentials and underlying implementation will take care of everything else. Our implementation is strictly non pre-emptive, so the login information is sent always as a response to 401 Http Status Code. If the Basic and Digest are not good enough and there is a need to use some custom scheme or something which is not yet supported in Tyrus, custom Authenticator can be registered and the authentication part of the handshake process will be handled by it. Please seeClient HTTP Authentication chapter in the user guide for more details. There are other features, like fine-grain threadpool configuration for JDK client container, build-in Http redirect support and some reshuffling related to unifying the location of client configuration classes and properties definition – every property should be now part of ClientProperties class. All new features are described in the user guide – in chapterTyrus proprietary configuration. Update – Tyrus 1.8.1 There was another slightly late reported issue related to running in environments with SecurityManager enabled, so this version fixes that. Another noteworthy fixes are TYRUS-355 and TYRUS-361; the first one is about incorrect thread factory used for shared container timeout, which resulted in JVM waiting for that thread and not exiting as it should. The other issue enables relative URIs in Location header when using redirect feature. Links Tyrus homepage mailing list JIRA Complete list of changes: Bug [TYRUS-333] – Multiple endpoints on one client [TYRUS-334] – When connection is closed by a peer, periodic heartbeat pong is not stopped [TYRUS-336] – ReaderBuffer.getNextChars() keeps blocking a server thread after client has closed the session [TYRUS-338] – JDK client SSL filter needs better synchronization during handshake phase [TYRUS-339] – SSL hostname verification is missing [TYRUS-340] – Test PathParamTest are not stable with JDK client [TYRUS-341] – A control frame inside a stream of continuation frames is treated as the part of the stream [TYRUS-343] – ControlFrameInDataStreamTest does not pass on GF [TYRUS-345] – NPE is thrown, when shared container timeout property in JDK client is not set [TYRUS-346] – IllegalStateException is thrown, when using proxy in JDK client [TYRUS-347] – Introduce better synchronization in JDK client thread pool [TYRUS-348] – When a client and server close connection simultaneously, JDK client throws NPE [TYRUS-356] – Tyrus cannot determine the connection port for a wss URL [TYRUS-357] – Exception thrown in MessageHandler#OnMessage is not caught in @OnError method [TYRUS-359] – Client based on Java 7 Asynchronous IO makes application unexitable Improvement [TYRUS-328] – JDK 1.7 AIO Client container – threads – (setting threadpool, limits, …) [TYRUS-332] – Consolidate shared client properties into one file. [TYRUS-337] – Create an SSL version of Basic Servlet test New Feature [TYRUS-228] – Add client support for HTTP Basic/Digest Task [TYRUS-330] – create/run tests/servlet/basic via wss [TYRUS-335] – [clustering] – introduce RemoteSession and expose them via separate method (not include remote sessions in the getOpenSessions()) [TYRUS-344] – Introduce Client support for HTTP Redirect

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• HOWTO Turn off SPARC T4 or Intel AES-NI crypto acceleration.

  - by darrenm

  Since we released hardware crypto acceleration for SPARC T4 and Intel AES-NI support we have had a common question come up: 'How do I test without the hardware crypto acceleration?'. Initially this came up just for development use so developers can do unit testing on a machine that has hardware offload but still cover the code paths for a machine that doesn't (our integration and release testing would run on all supported types of hardware anyway).  I've also seen it asked in a customer context too so that we can show that there is a performance gain from the hardware crypto acceleration, (not just the fact that SPARC T4 much faster performing processor than T3) and measure what it is for their application. With SPARC T2/T3 we could easily disable the hardware crypto offload by running 'cryptoadm disable provider=n2cp/0'.  We can't do that with SPARC T4 or with Intel AES-NI because in both of those classes of processor the encryption doesn't require a device driver instead it is unprivileged user land callable instructions. Turns out there is away to do this by using features of the Solaris runtime loader (ld.so.1). First I need to expose a little bit of implementation detail about how the Solaris Cryptographic Framework is implemented in Solaris 11.  One of the new Solaris 11 features of the linker/loader is the ability to have a single ELF object that has multiple different implementations of the same functions that are selected at runtime based on the capabilities of the machine.  The alternate to this is having the application coded to call getisax() and make the choice itself.  We use this functionality of the linker/loader when we build the userland libraries for the Solaris Cryptographic Framework (specifically libmd.so, and the unfortunately misnamed due to historical reasons libsoftcrypto.so) The Solaris linker/loader allows control of a lot of its functionality via environment variables, we can use that to control the version of the cryptographic functions we run.  To do this we simply export the LD_HWCAP environment variable with values that tell ld.so.1 to not select the HWCAP section matching certain features even if isainfo says they are present.  For SPARC T4 that would be: export LD_HWCAP="-aes -des -md5 -sha256 -sha512 -mont -mpul" and for Intel systems with AES-NI support: export LD_HWCAP="-aes" This will work for consumers of the Solaris Cryptographic Framework that use the Solaris PKCS#11 libraries or use libmd.so interfaces directly.  It also works for the Oracle DB and Java JCE.  However does not work for the default enabled OpenSSL "t4" or "aes-ni" engines (unfortunately) because they do explicit calls to getisax() themselves rather than using multiple ELF cap sections. However we can still use OpenSSL to demonstrate this by explicitly selecting "pkcs11" engine  using only a single process and thread.  $ openssl speed -engine pkcs11 -evp aes-128-cbc ... type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes aes-128-cbc 54170.81k 187416.00k 489725.70k 805445.63k 1018880.00k $ LD_HWCAP="-aes" openssl speed -engine pkcs11 -evp aes-128-cbc ... type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes aes-128-cbc 29376.37k 58328.13k 79031.55k 86738.26k 89191.77k We can clearly see the difference this makes in the case where AES offload to the SPARC T4 was disabled. The "t4" engine is faster than the pkcs11 one because there is less overhead (again on a SPARC T4-1 using only a single process/thread - using -multi you will get even bigger numbers). $ openssl speed -evp aes-128-cbc ... type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes aes-128-cbc 85526.61k 89298.84k 91970.30k 92662.78k 92842.67k Yet another cool feature of the Solaris linker/loader, thanks Rod and Ali. Note these above openssl speed output is not intended to show the actual performance of any particular benchmark just that there is a significant improvement from using hardware acceleration on SPARC T4. For cryptographic performance benchmarks see the http://blogs.oracle.com/BestPerf/ postings.

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• Critical Threads Optimization

  - by Rafael Vanoni

  Background One of the more common issues we've been seeing in the field is the growing difficulty in optimizing performance of multi-threaded applications. A good portion of this difficulty is due to the increasing complexity of modern processors that present various degrees of sharing relationships between hardware components. Take any current CMT processor and you'll find any number of CPUs sharing execution pipelines, floating point units, caches, etc. Consequently, applying the traditional recipe of one software thread for each CPU will have varying degrees of success, according to the layout of the underlying hardware. On top of this increasing complexity we've also seen processors with features that aim at dynamically resourcing software threads according to their utilization. Intel's Turbo Boost allows processors to increase their operating frequency if there is enough thermal headroom available and the processor isn't fully utilized. More recently, the SPARC T4 processor introduced dynamic threading, allowing each core to dynamically allocate more resources to its active CPUs. Both cases are in essence recognizing that current processors will be running a wide mix of workloads, some will be designed for throughput, others for low latency. The hardware is providing mechanisms to dynamically resource threads according to their runtime behavior. We're very aware of these challenges in Solaris, and have been working to provide the best out of box performance while providing mechanisms to further optimize applications when necessary. The Critical Threads Optimzation was introduced in Solaris 10 8/11 and Solaris 11 as one such mechanism that allows customers to both address issues caused by contention over shared hardware resources and explicitly take advantage of features such as T4's dynamic threading. What it is The basic idea is to allow performance critical threads to execute with more exclusive access to hardware resources. For example, when deploying an application that implements a producer/consumer model, it'll likely be advantageous to give the producer more exclusive access to the hardware instead of having it competing for resources with all the consumers. In the case of a T4 based system, we may want to have a producer running by itself on a single core and create one consumer for each of the remaining CPUs. With the Critical Threads Optimization we're extending the semantics of scheduling priorities (which thread should run first) to include priority over shared resources (which thread should have more "space"). Now the scheduler will not only run higher priority threads first: it will also provide them with more exclusive access to hardware resources if they are available. How does it work ? Using the previous example in Solaris 11, all you'd have to do would be to place the producer in the Fixed Priority (FX) scheduling class at priority 60, or in the Real Time (RT) class at any priority and Solaris will try to give it more "hardware space". On both Solaris 10 8/11 and Solaris 11 this can be achieved through the existing priocntl(1,2) and priocntlset(2) interfaces. If your application already assigns these priorities to performance critical threads, there's no additional step you need to take. One important aspect of this optimization is that it requires some level of idleness in the system, either as a result of sizing the application before hand or through periods of transient idleness during runtime. If the system is fully committed, the scheduler will put all the available CPUs to work.Best practices If you're an application developer, we encourage you to look into assigning the right priorities for the different threads in your application. Solaris provides different scheduling classes (Time Share, Interactive, Fair Share, Fixed Priority and Real Time) that offer different policies and behaviors. It is not always simple to figure out which set of threads are critical to the performance of a workload, and it may not always be feasible to take advantage of this optimization, but we believe that this can be correctly (and safely) done during development. Overall, the out of box performance in Solaris should meet your workload's requirements. If you are looking into that extra bit of performance, then the Critical Threads Optimization may be what you're looking for.

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• Impressions on jQuery Mobile

  - by Jeff

  For the uninitiated, jQuery Mobile is a sweet little client framework that turns regular HTML into something more touch and mobile friendly. It results in a user interface that has bigger targets, rounded corners and simple skinning capability. When it was announced that ASP.NET MVC 4 would include support for a mobile-sensitive view engine, offering up alternate views for clients that fit the mobile profile, I was all over that. Combined with jQuery Mobile, it brought a chance to do some experimentation. I blitzed through the views in POP Forums and converted them all to mobile views. (For the curious, this first pass can be found here on CodePlex, while a more recent update that uses RC 2 of jQuery Mobile v1.1.0 is running on the demo site.) Initially, it was kind of a mixed bag. The jQuery demo site also acts as documentation, and it’s reasonably complete. I had no problem getting up a lot of basic views quickly, splitting out portions of some pages as subpages that they quickly load in. The default behavior in the older version was to slide the pages in, which looked a little weird when you were using a back button. They’ve since changed it so the default transition is a fade in/out. Because you’re dealing with Web pages, I don’t think anyone is really under the illusion that you’re not using a native app, so I don’t know that this matters. I’ve tested extensively on iPad and Windows Phone, and to be honest, I’ve encountered a lot of issues. On Windows Phone, there is some kind of inconsistency that prevents the proper respect for the viewport settings. The text background on text fields (for labeling) doesn’t work, either. On both platforms, certain in-DOM page navigation links work only half of the time. Is this an issue of user error? Probably, but that’s what’s frustrating about it. Most of what you accomplish with this framework involves decorating various elements with CSS classes. There isn’t any design-time safety to speak of to make sure that you’re doing it right. I think the issues can be overcome, but there are some trade-offs to consider. The first is download size. Yes, the scripts and CSS do get cached, but that first hit will cost nearly 40k for the mobile parts. That’s still a lot when you’re on some crappy AT&T EDGE network, or hotel Wi-Fi. Then you have to ask yourself, do you really want your app to look like it’s native to iOS? I’m not saying that’s a bad thing, because consistent UI is good, but you will end up feeling a whole lot of sameness, and maybe you don’t want that. I did some experimentation to try and Metro-ize the jQuery Mobile theme, and it’s kind of a mixed bag. It mostly works, but you get some weirdness on badges and with buttons that I’m not crazy about. It probably just means you need to keep tweaking. At this point, I’m a little torn about whether or not I’ll use it for POP Forums or one of the sites I’m working on. The benefits are pretty strong, but figuring out where I’m doing it wrong is proving a little time consuming.

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• How do I use setFilmSize in panda3d to achieve the correct view?

  - by lhk

  I'm working with Panda3d and recently switched my game to isometric rendering. I moved the virtual camera accordingly and set an orthographic lens. Then I implemented the classes "Map" and "Canvas". A canvas is a dynamically generated mesh: a flat quad. I'm using it to render the ingame graphics. Since the game itself is still set in a 3d coordinate system I'm planning to rely on these canvases to draw sprites. I could have named this class "Tile" but as I'd like to use it for non-tile sketches (enemies, environment) as well I thought canvas would describe it's function better. Map does exactly what it's name suggests. Its constructor receives the number of rows and columns and then creates a standard isometric map. It uses the canvas class for tiles. I'm planning to write a map importer that reads a file to create maps on the fly. Here's the canvas implementation: class Canvas: def __init__(self, texture, vertical=False, width=1,height=1): # create the mesh format=GeomVertexFormat.getV3t2() format = GeomVertexFormat.registerFormat(format) vdata=GeomVertexData("node-vertices", format, Geom.UHStatic) vertex = GeomVertexWriter(vdata, 'vertex') texcoord = GeomVertexWriter(vdata, 'texcoord') # add the vertices for a flat quad vertex.addData3f(1, 0, 0) texcoord.addData2f(1, 0) vertex.addData3f(1, 1, 0) texcoord.addData2f(1, 1) vertex.addData3f(0, 1, 0) texcoord.addData2f(0, 1) vertex.addData3f(0, 0, 0) texcoord.addData2f(0, 0) prim = GeomTriangles(Geom.UHStatic) prim.addVertices(0, 1, 2) prim.addVertices(2, 3, 0) self.geom = Geom(vdata) self.geom.addPrimitive(prim) self.node = GeomNode('node') self.node.addGeom(self.geom) # this is the handle for the canvas self.nodePath=NodePath(self.node) self.nodePath.setSx(width) self.nodePath.setSy(height) if vertical: self.nodePath.setP(90) # the most important part: "Drawing" the image self.texture=loader.loadTexture(""+texture+".png") self.nodePath.setTexture(self.texture) Now the code for the Map class class Map: def __init__(self,rows,columns,size): self.grid=[] for i in range(rows): self.grid.append([]) for j in range(columns): # create a canvas for the tile. For testing the texture is preset tile=Canvas(texture="../assets/textures/flat_concrete",width=size,height=size) x=(i-1)*size y=(j-1)*size # set the tile up for rendering tile.nodePath.reparentTo(render) tile.nodePath.setX(x) tile.nodePath.setY(y) # and store it for later access self.grid[i].append(tile) And finally the usage def loadMap(self): self.map=Map(10, 10, 1) this function is called within the constructor of the World class. The instantiation of world is the entry point to the execution. The code is pretty straightforward and runs good. Sadly the output is not as expected: Please note: The problem is not the white rectangle, it's my player object. The problem is that although the map should have equal width and height it's stretched weirdly. With orthographic rendering I expected the map to be a perfect square. What did I do wrong ? UPDATE: I've changed the viewport. This is how I set up the orthographic camera: lens = OrthographicLens() lens.setFilmSize(40, 20) base.cam.node().setLens(lens) You can change the "aspect" by modifying the parameters of setFilmSize. I don't know exactly how they are related to window size and screen resolution but after testing a little the values above seem to work for me. Now everything is rendered correctly as long as I don't resize the window. Every change of the window's size as well as switching to fullscreen destroys the correct rendering. I know that implementing a listener for resize events is not in the scope of this question. However I wonder why I need to make the Film's height two times bigger than its width. My window is quadratic ! Can you tell me how to find out correct setting for the FilmSize ? UPDATE 2: I can imagine that it's hard to envision the behaviour of the game. At first glance the obvious solution is to pass the window's width and height in pixels to setFilmSize. There are two problems with that approach. The parameters for setFilmSize are ingame units. You'll get a way to big view if you pass the pixel size For some strange reason the image is distorted if you pass equal values for width and height. Here's the output for setFilmSize(800,800) You'll have to stress your eyes but you'll see what I mean

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• Node.js Lockstep Multiplayer Architecture

  - by Wakaka

  Background I'm using the lockstep model for a multiplayer Node.js/Socket.IO game in a client-server architecture. User input (mouse or keypress) is parsed into commands like 'attack' and 'move' on the client, which are sent to the server and scheduled to be executed on a certain tick. This is in contrast to sending state data to clients, which I don't wish to use due to bandwidth issues. Each tick, the server will send the list of commands on that tick (possibly empty) to each client. The server and all clients will then process the commands and simulate that tick in exactly the same way. With Node.js this is actually quite simple due to possibility of code sharing between server and client. I'll just put the deterministic simulator in the /shared folder which can be run by both server and client. The server simulation is required so that there is an authoritative version of the simulation which clients cannot alter. Problem Now, the game has many entity classes, like Unit, Item, Tree etc. Entities are created in the simulator. However, for each class, it has some methods that are shared and some that are client-specific. For instance, the Unit class has addHp method which is shared. It also has methods like getSprite (gets the image of the entity), isVisible (checks if unit can be seen by the client), onDeathInClient (does a bunch of stuff when it dies only on the client like adding announcements) and isMyUnit (quick function to check if the client owns the unit). Up till now, I have been piling all the client functions into the shared Unit class, and adding a this.game.isServer() check when necessary. For instance, when the unit dies, it will call if (!this.game.isServer()) { this.onDeathInClient(); }. This approach has worked pretty fine so far, in terms of functionality. But as the codebase grew bigger, this style of coding seems a little strange. Firstly, the client code is clearly not shared, and yet is placed under the /shared folder. Secondly, client-specific variables for each entity are also instantiated on the server entity (like unit.sprite) and can run into problems when the server cannot instantiate the variable (it doesn't have Image class like on browsers). So my question is, is there a better way to organize the client code, or is this a common way of doing things for lockstep multiplayer games? I can think of a possible workaround, but it does have its own problems. Possible workaround (with problems) I could use Javascript mixins that are only added when in a browser. Thus, in the /shared/unit.js file in the /shared folder, I would have this code at the end: if (typeof exports !== 'undefined') module.exports = Unit; else mixin(Unit, LocalUnit); Then I would have /client/localunit.js store an object LocalUnit of client-side methods for Unit. Now, I already have a publish-subscribe system in place for events in the simulator. To remove the this.game.isServer() checks, I could publish entity-specific events whenever I want the client to do something. For instance, I would do this.publish('Death') in /shared/unit.js and do this.subscribe('Death', this.onDeathInClient) in /client/localunit.js. But this would make the simulator's event listeners list on the server and the client different. Now if I want to clear all subscribed events only from the shared simulator, I can't. Of course, it is possible to create two event subscription systems - one client-specific and one shared - but now the publish() method would have to do if (!this.game.isServer()) { this.publishOnClient(event); }. All in all, the workaround off the top of my head seems pretty complicated for something as simple as separating the client and shared code. Thus, I wonder if there is an established and simpler method for better code organization, hopefully specific to Node.js games.

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• SQLAuthority News – Speaking at Southeast Asia SharePoint Conference 2013 – Singapore

  - by pinaldave

  Two years ago I spoke at Southeast Asia SharePoint Conference 2011, Singapore and I had a fantastic time to present to the Singapore audience. The session was very well received and lots of interest was generated. The event is back again this year and with much bigger scale. I will be presenting on SQL Server and Sharepoint subject at the conference. Session Details: Title: Performance in 60 Seconds – Database Tricks Every SharePoint Developer & Admin MUST Know Abstract: SharePoint Developers and System Administrators often come across situations where they face a slow server response, even though their hardware specifications are above  par. This session is for all the SharePoint Developers who want their server to perform at blazing fast speed but want to invest very little time to make it happen. We will go over various database tricks which require absolutely no time to master and require practically no SQL coding at all. After attending this session, Developers will only need 60 seconds to improve performance of their database server in their SharePoint implementation. Date and Time: January 18, 20013 - 3:15 PM-4:15 PM Location: Max Atria is located at Singapore Expo, 1 Expo Drive, Singapore Tel 65 6403 2160 This session will cover lots of interesting tips and tricks about SQL Server and SharePoint co-exists together. I promise that every attendee will walk out with a trick which they can walk out of session and directly apply to their production server to improve its performance. The event is going to be again fantastic event – if you are in Singapore – you must not miss this event. If you are planning vacation – this is the right time to take days off and travel to Singapore for vacation. The event features over 30 sessions to choose from, focus on three areas of business gain: Exploring Information, Improving Productivity and Making it Work. This event has an excellent line up of international speakers (speakers traveling from the USA, Australia, New Zealand, Sri Lanka and India). Register early to reserve a spot at your choice of more than 30 classes taught by Microsoft Certified Masters, MVPs, and other top SharePoint experts! Here I have attempted to answer a few of the questions which every SharePoint professional half: Which sessions suit my skill level? Click here. What sessions are right for me? Click here. Which sessions are of my interests? Click here. Which sessions are on when? Click here. If you register by next Friday, 14, December – you can save $126 on the regular price of the conference. Prizes, Giveaways and … I love conference goodies – I collect them as a souvenir . This event is known for its generous prizes. The first 100 people to register on the day will get a SPECIAL gift at the event. Additionally there are exhibitor booth give away too. Here is the page listing all the prizes and giveaways. Do leave a comment or send me email if you are going to the event, we can sit together and have a coffee. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology

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• Types of semantic bugs, logic errors [closed]

  - by C-Otto

  I am a PhD student and currently focus on automatically finding instances of new types of bugs in (Java) programs that cannot be found by existing tools like FindBugs. The existing tool currently is used to prove/disprove termination of (Java) programs. I have some ideas (see below), but I could need more input from you (experienced programmers, potential users of my tool). What kind of bugs do you wish to find? What types of bugs exist and might be suitable for my analysis? One strength of the approach I use is detailled information about the heap. So in contrast to FindBugs, I can work with knowledge of the form "variable x and variable y are disjoint on the heap" or "variable z is not cyclic". It is also possible to see if a method might have side effects (and if so, which variables may/may not be affected by it). Example 1: Vacuous call: Graph graphOne = createGraph(); Graph graphTwo = createGraph(); Node source = graphTwo.getRootNode(); for (Node n : graphOne.getNodes()) { if (areConnected(source, n)) { graphTwo.addNode(n); } } Imagine createGraph() creates a fresh graph, so that graphOne and graphTwo are disjoint on the heap. Then, because source is taken from graphTwo instead of graphOne, the call to areConnected always returns false. In this situation I could find out that the call areConnected is useless (because it does not have any side effect and the return value always is false) which helps finding the real bug (taking source from the wrong graph). For this the information that x and y are disjoint (because graphOne and graphTwo are disjoint) is crucial. This bug is related to calling x.equals(y) where x and y are objects of different classes. In this scenario, most implementations of equals() always return false, which most likely is not the intended result. FindBugs already finds this bug (hardcoded to equals(), semantics of implementation is not checked). Example 2: Useless code: someCode(); while (something()) { yetMoreSomething(); } moreCode(); In the case that the loop (so the code in something() and yetMoreSomething()) does not modify anything visible outside the loop, it does not make sense to run this code - the program has the same behaviour as someCode(); moreCode() (i.e., without the loop). To find this out, one needs detailled information about the side effects of the (possibly useless) code. If I can prove that the code does not have any side effect that can be observed afterwards (in the example: in moreCode() or later), then the code indeed is useless. Of course, here Input/Output of any form must be seen as a side effect, so that a System.out.println(...) is not considered useless. Example 3: Ignored return value: Instead of x = foo(); and making use of x, the method is called without storing the result: foo();. If the method does not have any side effect, its invocation is useless and can be dropped. Most likely, the bug here is that the returned value should have been used. Here, too, detailled information about side effects are needed. Can you think of similar types of bugs that might be detected (only) with detailled information about the heap, side effects, semantics of called methods, ...? Did you encounter bugs related to the ones shown below in "real life"? By the way, the tool is AProVE and Java related publications can be found on my homepage. Thanks a lot, Carsten

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• dynamic? I'll never use that ... or then again, maybe it could ...

  - by adweigert

  So, I don't know about you, but I was highly skeptical of the dynamic keywork when it was announced. I thought to myself, oh great, just another move towards VB compliance. Well after seeing it being used in things like DynamicXml (which I use for this example) I then was working with a MVC controller and wanted to move some things like operation timeout of an action to a configuration file. Thinking big picture, it'd be really nice to have configuration for all my controllers like that. Ugh, I don't want to have to create all those ConfigurationElement objects... So, I started thinking self, use what you know and do something cool ... Well after a bit of zoning out, self came up with use a dynamic object duh! I was thinking of a config like this ...<controllers> <add type="MyApp.Web.Areas.ComputerManagement.Controllers.MyController, MyApp.Web"> <detail timeout="00:00:30" /> </add> </controllers> So, I ended up with a couple configuration classes like this ...blic abstract class DynamicConfigurationElement : ConfigurationElement { protected DynamicConfigurationElement() { this.DynamicObject = new DynamicConfiguration(); } public DynamicConfiguration DynamicObject { get; private set; } protected override bool OnDeserializeUnrecognizedAttribute(string name, string value) { this.DynamicObject.Add(name, value); return true; } protected override bool OnDeserializeUnrecognizedElement(string elementName, XmlReader reader) { this.DynamicObject.Add(elementName, new DynamicXml((XElement)XElement.ReadFrom(reader))); return true; } } public class ControllerConfigurationElement : DynamicConfigurationElement { [ConfigurationProperty("type", Options = ConfigurationPropertyOptions.IsRequired | ConfigurationPropertyOptions.IsKey)] public string TypeName { get { return (string)this["type"]; } } public Type Type { get { return Type.GetType(this.TypeName, true); } } } public class ControllerConfigurationElementCollection : ConfigurationElementCollection { protected override ConfigurationElement CreateNewElement() { return new ControllerConfigurationElement(); } protected override object GetElementKey(ConfigurationElement element) { return ((ControllerConfigurationElement)element).Type; } } And then had to create the meat of the DynamicConfiguration class which looks like this ...public class DynamicConfiguration : DynamicObject { private Dictionary<string, object> properties = new Dictionary<string, object>(StringComparer.CurrentCultureIgnoreCase); internal void Add<T>(string name, T value) { this.properties.Add(name, value); } public override bool TryGetMember(GetMemberBinder binder, out object result) { var propertyName = binder.Name; result = null; if (this.properties.ContainsKey(propertyName)) { result = this.properties[propertyName]; } return true; } } So all being said, I made a base controller class like a good little MVC-itizen ...public abstract class BaseController : Controller { protected BaseController() : base() { var configuration = ManagementConfigurationSection.GetInstance(); var controllerConfiguration = configuration.Controllers.ForType(this.GetType()); if (controllerConfiguration != null) { this.Configuration = controllerConfiguration.DynamicObject; } } public dynamic Configuration { get; private set; } } And used it like this ...public class MyController : BaseController { static readonly string DefaultDetailTimeout = TimeSpan.MaxValue.ToString(); public MyController() { this.DetailTimeout = TimeSpan.Parse(this.Configuration.Detail.Timeout ?? DefaultDetailTimeout); } public TimeSpan DetailTimeout { get; private set; } } And there I have an actual use for the dynamic keyword ... never thoguht I'd see the day when I first heard of it as I don't do much COM work ... oh dont' forget this little helper extension methods to find the controller configuration by the controller type.public static ControllerConfigurationElement ForType<T>(this ControllerConfigurationElementCollection collection) { Contract.Requires(collection != null); return ForType(collection, typeof(T)); } public static ControllerConfigurationElement ForType(this ControllerConfigurationElementCollection collection, Type type) { Contract.Requires(collection != null); Contract.Requires(type != null); return collection.Cast<ControllerConfigurationElement>().Where(element => element.Type == type).SingleOrDefault(); } Sure, it isn't perfect and I'm sure I can tweak it over time, but I thought it was a pretty cool way to take advantage of the dynamic keyword functionality. Just remember, it only validates you did it right at runtime, which isn't that bad ... is it? And yes, I did make it case-insensitive so my code didn't have to look like my XML objects, tweak it to your liking if you dare to use this creation.

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• Design pattern for logging changes in parent/child objects saved to database

  - by andrew

  I’ve got a 2 database tables in parent/child relationship as one-many. I’ve got three classes representing the data in these two tables: Parent Class { Public int ID {get; set;} .. other properties } Child Class { Public int ID {get;set;} Public int ParentID {get; set;} .. other properties } TogetherClass { Public Parent Parent; Public List<Child> ChildList; } Lastly I’ve got a client and server application – I’m in control of both ends so can make changes to both programs as I need to. Client makes a request for ParentID and receives a Together Class for the matching parent, and all of the child records. The client app may make changes to the children – add new children, remove or modify existing ones. Client app then sends the Together Class back to the server app. Server app needs to update the parent and child records in the database. In addition I would like to be able to log the changes – I’m doing this by having 2 separate tables one for Parent, one for child; each containing the same columns as the original plus date time modified, by whom and a list of the changes. I’m unsure as to the best approach to detect the changes in records – new records, records to be deleted, records with no fields changed, records with some fields changed. I figure I need to read the parent & children records and compare those to the ones in the Together Class. Strategy A: If Together class’s child record has an ID of say 0, that indicates a new record; insert. Any deleted child records are no longer in the Together Class; see if any of the comparison child records are not found in the Together class and delete if not found (Compare using ID). Check each child record for changes and if changed log. Strategy B: Make a new Updated TogetherClass UpdatedClass { Public Parent Parent {get; set} Public List<Child> ListNewChild {get;set;} Public List<Child> DeletedChild {get;set;} Public List<Child> ExistingChild {get;set;} // used for no changes and modified rows } And then process as per the list. The reason why I’m asking for ideas is that both of these solutions don’t seem optimal to me and I suspect this problem has been solved already – some kind of design pattern ? I am aware of one potential problem in this general approach – that where Client App A requests a record; App B requests same record; A then saves changes; B then saves changes which may overwrite changes A made. This is a separate locking issue which I’ll raise a separate question for if I’ve got trouble implementing. The actual implementation is c#, SQL Server and WCF between client and server - sharing a library containing the class implementations. Apologies if this is a duplicate post – I tried searching various terms without finding a match though.

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• Changes in Language Punctuation [closed]

  - by Wes Miller

  More social curiosity than actual programming question... (I got shot for posting this on Stack Overflow. They sent me here. At least i hope here is where they meant.) Based on the few responses I got before the content police ran me off Stack Overflow, I should note that I am legally blind and neatness and consistency in programming are my best friends. A thousand years ago when I took my first programming class (Fortran 66) and a mere 500 years ago when I tokk my first C and C++ classes, there were some pretty standard punctuation practices across languages. I saw them in Basic (shudder), PL/1, PL/AS, Rexx even Pascal. Ok, APL2 is not part of this discussion. Each language has its own peculiar punctuation. Pascal's periods, Fortran's comma separated do loops, almost everybody else's semicolons. As I learned it, each language also has KEYWORDS (if, for, do, while, until, etc.) which are set off by whitespace (or the left margin) if, etc. Each language has function, subroutines of whatever they're called. Some built-in some user coded. They were set off by function_name( parameters );. As in sqrt( x ) or rand( y ); Lately, there seems to be a new set of punctuation rules. Especially in c++ where initializers get glued onto the end of variable declarations int x(0); or auto_ptr p(new gizmo); This usually, briefly fools me into thinking someone is declaring a function prototype or using a function as a integer. Then "if" and 'for' seems to have grown parens; if(true) for(;;), etc. Since when did keywords become functions. I realize some people think they ARE functions with iterators as parameters. But if "for" is a function, where did the arg separating commas go? And finally, functions seem to have shed their parens; sqrt (2) select (...) I know, I koow, loosening whitespace rules is good. Keep reading. Question: when did the old ways disappear and this new way come into vogue? Does anyone besides me find it irritating to read and that the information that the placement of punctuation used to convey is gone? I know full well that K&R put the { at the end of the "if" or "for" to save a byte here and there. Can't use that excuse here. Space as an excuse for loss of readability died as HDD space soared past 100 MiB. Your thoughts are solicited. If there is a good reason to do this, I'll gladly learn it and maybe in another 50 years I'll get used to it. Of course it's good that compilers recognize these (IMHO) typos and keep right on going, but just because you CAN code it that way doesn't mean you HAVE to, right?

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• WebLogic Server Performance and Tuning: Part II - Thread Management

  - by Gokhan Gungor

  WebLogic Server, like any other java application server, provides resources so that your applications use them to provide services. Unfortunately none of these resources are unlimited and they must be managed carefully. One of these resources is threads which are pooled to provide better throughput and performance along with the fast response time and to avoid deadlocks. Threads are execution points that WebLogic Server delivers its power and execute work. Managing threads is very important because it may affect the overall performance of the entire system. In previous releases of WebLogic Server 9.0 we had multiple execute queues and user defined thread pools. There were different queues for different type of work which had fixed number of execute threads.  Tuning of this thread pools and finding the proper number of threads was time consuming which required many trials. WebLogic Server 9.0 and the following releases use a single thread pool and a single priority-based execute queue. All type of work is executed in this single thread pool. Its size (thread count) is automatically decreased or increased (self-tuned). The new “self-tuning” system simplifies getting the proper number of threads and utilizing them.Work manager allows your applications to run concurrently in multiple threads. Work manager is a mechanism that allows you to manage and utilize threads and create rules/guidelines to follow when assigning requests to threads. We can set a scheduling guideline or priority a request with a work manager and then associate this work manager with one or more applications. At run-time, WebLogic Server uses these guidelines to assign pending work/requests to execution threads. The position of a request in the execute queue is determined by its priority. There is a default work manager that is provided. The default work manager should be sufficient for most applications. However there can be cases you want to change this default configuration. Your application(s) may be providing services that need mixture of fast response time and long running processes like batch updates. However wrong configuration of work managers can lead a performance penalty while expecting improvement.We can define/configure work managers at;•    Domain Level: config.xml•    Application Level: weblogic-application.xml •    Component Level: weblogic-ejb-jar.xml or weblogic.xml(For a specific web application use weblogic.xml)We can use the following predefined rules/constraints to manage the work;•    Fair Share Request Class: Specifies the average thread-use time required to process requests. The default is 50.•    Response Time Request Class: Specifies a response time goal in milliseconds.•    Context Request Class: Assigns request classes to requests based on context information.•    Min Threads Constraint: Limits the number of concurrent threads executing requests.•    Max Threads Constraint: Guarantees the number of threads the server will allocate to requests.•    Capacity Constraint: Causes the server to reject requests only when it has reached its capacity. Let’s create a work manager for our application for a long running work.Go to WebLogic console and select Environment | Work Managers from the domain structure tree. Click New button and select Work manager and click next. Enter the name for the work manager and click next. Then select the managed server instances(s) or clusters from available targets (the one that your long running application is deployed) and finish. Click on MyWorkManager, and open the Configuration tab and check Ignore Stuck Threads and save. This will prevent WebLogic to tread long running processes (that is taking more than a specified time) as stuck and enable to finish the process.

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