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OS Analytics - Deep Dive Into Your OS

- by Eran_Steiner

Enterprise Manager Ops Center provides a feature called "OS Analytics". This feature allows you to get a better understanding of how the Operating System is being utilized. You can research the historical usage as well as real time data. This post will show how you can benefit from OS Analytics and how it works behind the scenes. We will have a call to discuss this blog - please join us!Date: Thursday, November 1, 2012Time: 11:00 am, Eastern Daylight Time (New York, GMT-04:00)1. Go to https://oracleconferencing.webex.com/oracleconferencing/j.php?ED=209833067&UID=1512092402&PW=NY2JhMmFjMmFh&RT=MiMxMQ%3D%3D2. If requested, enter your name and email address.3. If a password is required, enter the meeting password: oracle1234. Click "Join". To join the teleconference:Call-in toll-free number: 1-866-682-4770 (US/Canada) Other countries: https://oracle.intercallonline.com/portlets/scheduling/viewNumbers/viewNumber.do?ownerNumber=5931260&audioType=RP&viewGa=true&ga=ONConference Code: 7629343#Security code: 7777# Here is quick summary of what you can do with OS Analytics in Ops Center: View historical charts and real time value of CPU, memory, network and disk utilization Find the top CPU and Memory processes in real time or at a certain historical day Determine proper monitoring thresholds based on historical data View Solaris services status details Drill down into a process details View the busiest zones if applicable Where to start To start with OS Analytics, choose the OS asset in the tree and click the Analytics tab. You can see the CPU utilization, Memory utilization and Network utilization, along with the current real time top 5 processes in each category (click the image to see a larger version): In the above screen, you can click each of the top 5 processes to see a more detailed view of that process. Here is an example of one of the processes: One of the cool things is that you can see the process tree for this process along with some port binding and open file descriptors. On Solaris machines with zones, you get an extra level of tabs, allowing you to get more information on the different zones: This is a good way to see the busiest zones. For example, one zone may not take a lot of CPU but it can consume a lot of memory, or perhaps network bandwidth. To see the detailed Analytics for each of the zones, simply click each of the zones in the tree and go to its Analytics tab. Next, click the "Processes" tab to see real time information of all the processes on the machine: An interesting column is the "Target" column. If you configured Ops Center to work with Enterprise Manager Cloud Control, then the two products will talk to each other and Ops Center will display the correlated target from Cloud Control in this table. If you are only using Ops Center - this column will remain empty. Next, if you view a Solaris machine, you will have a "Services" tab: By default, all services will be displayed, but you can choose to display only certain states, for example, those in maintenance or the degraded ones. You can highlight a service and choose to view the details, where you can see the Dependencies, Dependents and also the location of the service log file (not shown in the picture as you need to scroll down to see the log file). The "Threshold" tab is particularly helpful - you can view historical trends of different monitored values and based on the graph - determine what the monitoring values should be: You can ask Ops Center to suggest monitoring levels based on the historical values or you can set your own. The different colors in the graph represent the current set levels: Red for critical, Yellow for warning and Blue for Information, allowing you to quickly see how they're positioned against real data. It's important to note that when looking at longer periods, Ops Center smooths out the data and uses averages. So when looking at values such as CPU Usage, try shorter time frames which are more detailed, such as one hour or one day. Applying new monitoring values When first applying new values to monitored attributes - a popup will come up asking if it's OK to get you out of the current Monitoring Policy. This is OK if you want to either have custom monitoring for a specific machine, or if you want to use this current machine as a "Gold image" and extract a Monitoring Policy from it. You can later apply the new Monitoring Policy to other machines and also set it as a default Monitoring Profile. Once you're done with applying the different monitoring values, you can review and change them in the "Monitoring" tab. You can also click the "Extract a Monitoring Policy" in the actions pane on the right to save all the new values to a new Monitoring Policy, which can then be found under "Plan Management" -> "Monitoring Policies". Visiting the past Under the "History" tab you can "go back in time". This is very helpful when you know that a machine was busy a few hours ago (perhaps in the middle of the night?), but you were not around to take a look at it in real time. Here's a view into yesterday's data on one of the machines: You can see an interesting CPU spike happening at around 3:30 am along with some memory use. In the bottom table you can see the top 5 CPU and Memory consumers at the requested time. Very quickly you can see that this spike is related to the Solaris 11 IPS repository synchronization process using the "pkgrecv" command. The "time machine" doesn't stop here - you can also view historical data to determine which of the zones was the busiest at a given time: Under the hood The data collected is stored on each of the agents under /var/opt/sun/xvm/analytics/historical/ An "os.zip" file exists for the main OS. Inside you will find many small text files, named after the Epoch time stamp in which they were taken If you have any zones, there will be a file called "guests.zip" containing the same small files for all the zones, as well as a folder with the name of the zone along with "os.zip" in it If this is the Enterprise Controller or the Proxy Controller, you will have folders called "proxy" and "sat" in which you will find the "os.zip" for that controller The actual script collecting the data can be viewed for debugging purposes as well: On Linux, the location is: /opt/sun/xvmoc/private/os_analytics/collect On Solaris, the location is /opt/SUNWxvmoc/private/os_analytics/collect If you would like to redirect all the standard error into a file for debugging, touch the following file and the output will go into it: # touch /tmp/.collect.stderr The temporary data is collected under /var/opt/sun/xvm/analytics/.collectdb until it is zipped. If you would like to review the properties for the Analytics, you can view those per each agent in /opt/sun/n1gc/lib/XVM.properties. Find the section "Analytics configurable properties for OS and VSC" to view the Analytics specific values. I hope you find this helpful! Please post questions in the comments below. Eran Steiner

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Sliding collision response

- by dbostream

I have been reading plenty of tutorials about sliding collision responses yet I am not able to implement it properly in my project. What I want to do is make a puck slide along the rounded corner boards of a hockey rink. In my latest attempt the puck does slide along the boards but there are some strange velocity behaviors. First of all the puck slows down a lot pretty much right away and then it slides for awhile and stops before exiting the corner. Even if I double the speed I get a similar behavior and the puck does not make it out of the corner. I used some ideas from this document http://www.peroxide.dk/papers/collision/collision.pdf. This is what I have: Update method called from the game loop when it is time to update the puck (I removed some irrelevant parts). I use two states (current, previous) which are used to interpolate the position during rendering. public override void Update(double fixedTimeStep) { /* Acceleration is set to 0 for now. */ Acceleration.Zero(); PreviousState = CurrentState; _collisionRecursionDepth = 0; CurrentState.Position = SlidingCollision(CurrentState.Position, CurrentState.Velocity * fixedTimeStep + 0.5 * Acceleration * fixedTimeStep * fixedTimeStep); /* Should not this be affected by a sliding collision? and not only the position. */ CurrentState.Velocity = CurrentState.Velocity + Acceleration * fixedTimeStep; Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private Vector2 SlidingCollision(Vector2 position, Vector2 velocity) { if(_collisionRecursionDepth > 5) return position; bool collisionFound = false; Vector2 futurePosition = position + velocity; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ if(!collisionFound) return futurePosition; /* If no collision was detected it is safe to move to the future position. */ /* It is not exactly the intersection point, but slightly before. */ Vector2 newPosition = intersectionPoint; /* oldVelocity is set to the distance from the newPosition(intersection point) to the position it had moved to had it not collided. */ Vector2 oldVelocity = futurePosition - newPosition; /* Project the distance left to move along the intersection normal. */ Vector2 newVelocity = oldVelocity - intersectionPointNormal * oldVelocity.DotProduct(intersectionPointNormal); if(newVelocity.LengthSq() < 0.001) return newPosition; /* If almost no speed, no need to continue. */ _collisionRecursionDepth++; return SlidingCollision(newPosition, newVelocity); } What am I doing wrong with the velocity? I have been staring at this for very long so I have gone blind. I have tried different values of recursion depth but it does not seem to make it better. Let me know if you need more information. I appreciate any help. EDIT: A combination of Patrick Hughes' and teodron's answers solved the velocity problem (I think), thanks a lot! This is the new code: I decided to use a separate recursion method now too since I don't want to recalculate the acceleration in each recursion. public override void Update(double fixedTimeStep) { Acceleration.Zero();// = CalculateAcceleration(fixedTimeStep); PreviousState = new MovingEntityState(CurrentState.Position, CurrentState.Velocity); CurrentState = SlidingCollision(CurrentState, fixedTimeStep); Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private MovingEntityState SlidingCollision(MovingEntityState state, double timeStep) { bool collisionFound = false; /* Calculate the next position given no detected collision. */ Vector2 futurePosition = state.Position + state.Velocity * timeStep; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ /* If no collision was detected it is safe to move to the future position. */ if (!collisionFound) return new MovingEntityState(futurePosition, state.Velocity); /* Set new position to the intersection point (slightly before). */ Vector2 newPosition = intersectionPoint; /* Project the new velocity along the intersection normal. */ Vector2 newVelocity = state.Velocity - 1.90 * intersectionPointNormal * state.Velocity.DotProduct(intersectionPointNormal); /* Calculate the time of collision. */ double timeOfCollision = Math.Sqrt((newPosition - state.Position).LengthSq() / (futurePosition - state.Position).LengthSq()); /* Calculate new time step, remaining time of full step after the collision * current time step. */ double newTimeStep = timeStep * (1 - timeOfCollision); return SlidingCollision(new MovingEntityState(newPosition, newVelocity), newTimeStep); } Even though the code above seems to slide the puck correctly please have a look at it. I have a few questions, if I don't multiply by 1.90 in the newVelocity calculation it doesn't work (I get a stack overflow when the puck enters the corner because the timeStep decreases very slowly - a collision is found early in every recursion), why is that? what does 1.90 really do and why 1.90? Also I have a new problem, the puck does not move parallell to the short side after exiting the curve; to be more exact it moves outside the rink (I am not checking for any collisions with the short side at the moment). When I perform the collision detection I first check that the puck is in the correct quadrant. For example bottom-right corner is quadrant four i.e. circleCenter.X < puck.X && circleCenter.Y puck.Y is this a problem? or should the short side of the rink be the one to make the puck go parallell to it and not the last collision in the corner? EDIT2: This is the code I use for collision detection, maybe it has something to do with the fact that I can't make the puck slide (-1.0) but only reflect (-2.0): /* Point is the current position (not the predicted one) and quadrant is 4 for the bottom-right corner for example. */ if (GeometryHelper.PointInCircleQuadrant(circleCenter, circleRadius, state.Position, quadrant)) { /* The line is: from = state.Position, to = futurePosition. So a collision is detected when from is inside the circle and to is outside. */ if (GeometryHelper.LineCircleIntersection2d(state.Position, futurePosition, circleCenter, circleRadius, intersectionPoint, quadrant)) { collisionFound = true; /* Set the intersection point to slightly before the real intersection point (I read somewhere this was good to do because of floting point precision, not sure exactly how much though). */ intersectionPoint = intersectionPoint - Vector2.NormalizeRet(state.Velocity) * 0.001; /* Normal at the intersection point. */ intersectionPointNormal = Vector2.NormalizeRet(circleCenter - intersectionPoint) } } When I set the intersection point, if I for example use 0.1 instead of 0.001 the puck travels further before it gets stuck, but for all values I have tried (including 0 - the real intersection point) it gets stuck somewhere (but I necessarily not get a stack overflow). Can something in this part be the cause of my problem? I can see why I get the stack overflow when using -1.0 when calculating the new velocity vector; but not how to solve it. I traced the time steps used in the recursion (initial time step is always 1/60 ~ 0.01666): Recursion depth Time step next recursive call [Start recursion, time step ~ 0.016666] 0 0,000985806527246773 [No collision, stop recursion] [Start recursion, time step ~ 0.016666] 0 0,0149596704364629 1 0,0144883449376379 2 0,0143155612984837 3 0,014224925727213 4 0,0141673917461608 5 0,0141265435314026 6 0,0140953966184117 7 0,0140704653746625 ...and so on. As you can see the collision is detected early in every recursive call which means the next time step decreases very slowly thus the recursion depth gets very big - stack overflow.

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Using Sitecore RenderingContext Parameters as MVC controller action arguments

- by Kyle Burns

I have been working with the Technical Preview of Sitecore 6.6 on a project and have been for the most part happy with the way that Sitecore (which truly is an MVC implementation unto itself) has been expanded to support ASP.NET MVC. That said, getting up to speed with the combined platform has not been entirely without stumbles and today I want to share one area where Sitecore could have really made things shine from the "it just works" perspective. A couple days ago I was asked by a colleague about the usage of the "Parameters" field that is defined on Sitecore's Controller Rendering data template. Based on the standard way that Sitecore handles a field named Parameters, I was able to deduce that the field expected key/value pairs separated by the "&" character, but beyond that I wasn't sure and didn't see anything from a documentation perspective to guide me, so it was time to dig and find out where the data in the field was made available. My first thought was that it would be really nice if Sitecore handled the parameters in this field consistently with the way that ASP.NET MVC handles the various parameter collections on the HttpRequest object and automatically maps them to parameters of the action method executing. Being the hopeful sort, I configured a name/value pair on one of my renderings, added a parameter with matching name to the controller action and fired up the bugger to see... that the parameter was not populated. Having established that the field's value was not going to be presented to me the way that I had hoped it would, the next assumption that I would work on was that Sitecore would handle this field similar to how they handle other similar data and would plug it into some ambient object that I could reference from within the controller method. After a considerable amount of guessing, testing, and cracking code open with Redgate's Reflector (a must-have companion to Sitecore documentation), I found that the most direct way to access the parameter was through the ambient RenderingContext object using code similar to: string myArgument = string.Empty; var rc = Sitecore.Mvc.Presentation.RenderingContext.CurrentOrNull; if (rc != null) { var parms = rc.Rendering.Parameters; myArgument = parms["myArgument"]; } At this point, we know how this field is used out of the box from Sitecore and can provide information from Sitecore's Content Editor that will be available when the controller action is executing, but it feels a little dirty. In order to properly test the action method I would have to do a lot of setup work and possible use an isolation framework such as Pex and Moles to get at a value that my action method is dependent upon. Notice I said that my method is dependent upon the value but in order to meet that dependency I've accepted another dependency upon Sitecore's RenderingContext. I'm a big believer in, when possible, ensuring that any piece of code explicitly advertises dependencies using the method signature, so I found myself still wanting this to work the same as if the parameters were in the request route, querystring, or form by being able to add a myArgument parameter to the action method and have this parameter populated by the framework. Lucky for us, the ASP.NET MVC framework is extremely flexible and provides some easy to grok and use extensibility points. ASP.NET MVC is able to provide information from the request as input parameters to controller actions because it uses objects which implement an interface called IValueProvider and have been registered to service the application. The most basic statement of responsibility for an IValueProvider implementation is "I know about some data which is indexed by key. If you hand me the key for a piece of data that I know about I give you that data". When preparing to invoke a controller action, the framework queries registered IValueProvider implementations with the name of each method argument to see if the ValueProvider can supply a value for the parameter. (the rest of this post will assume you're working along and make a lot more sense if you do) Let's pull Sitecore out of the equation for a second to simplify things and create an extremely simple IValueProvider implementation. For this example, I first create a new ASP.NET MVC3 project in Visual Studio, selecting "Internet Application" and otherwise taking defaults (I'm assuming that anyone reading this far in the post either already knows how to do this or will need to take a quick run through one of the many available basic MVC tutorials such as the MVC Music Store). Once the new project is created, go to the Index action of HomeController. This action sets a Message property on the ViewBag to "Welcome to ASP.NET MVC!" and invokes the View, which has been coded to display the Message. For our example, we will remove the hard coded message from this controller (although we'll leave it just as hard coded somewhere else - this is sample code). For the first step in our exercise, add a string parameter to the Index action method called welcomeMessage and use the value of this argument to set the ViewBag.Message property. The updated Index action should look like: public ActionResult Index(string welcomeMessage) { ViewBag.Message = welcomeMessage; return View(); } This represents the entirety of the change that you will make to either the controller or view. If you run the application now, the home page will display and no message will be presented to the user because no value was supplied to the Action method. Let's now write a ValueProvider to ensure this parameter gets populated. We'll start by creating a new class called StaticValueProvider. When the class is created, we'll update the using statements to ensure that they include the following: using System.Collections.Specialized; using System.Globalization; using System.Web.Mvc; With the appropriate using statements in place, we'll update the StaticValueProvider class to implement the IValueProvider interface. The System.Web.Mvc library already contains a pretty flexible dictionary-like implementation called NameValueCollectionValueProvider, so we'll just wrap that and let it do most of the real work for us. The completed class looks like: public class StaticValueProvider : IValueProvider { private NameValueCollectionValueProvider _wrappedProvider; public StaticValueProvider(ControllerContext controllerContext) { var parameters = new NameValueCollection(); parameters.Add("welcomeMessage", "Hello from the value provider!"); _wrappedProvider = new NameValueCollectionValueProvider(parameters, CultureInfo.InvariantCulture); } public bool ContainsPrefix(string prefix) { return _wrappedProvider.ContainsPrefix(prefix); } public ValueProviderResult GetValue(string key) { return _wrappedProvider.GetValue(key); } } Notice that the only entry in the collection matches the name of the argument to our HomeController's Index action. This is the important "secret sauce" that will make things work. We've got our new value provider now, but that's not quite enough to be finished. Mvc obtains IValueProvider instances using factories that are registered when the application starts up. These factories extend the abstract ValueProviderFactory class by initializing and returning the appropriate implementation of IValueProvider from the GetValueProvider method. While I wouldn't do so in production code, for the sake of this example, I'm going to add the following class definition within the StaticValueProvider.cs source file: public class StaticValueProviderFactory : ValueProviderFactory { public override IValueProvider GetValueProvider(ControllerContext controllerContext) { return new StaticValueProvider(controllerContext); } } Now that we have a factory, we can register it by adding the following line to the end of the Application_Start method in Global.asax.cs: ValueProviderFactories.Factories.Add(new StaticValueProviderFactory()); If you've done everything right to this point, you should be able to run the application and be presented with the home page reading "Hello from the value provider!". Now that you have the basics of the IValueProvider down, you have everything you need to enhance your Sitecore MVC implementation by adding an IValueProvider that exposes values from the ambient RenderingContext's Parameters property. I'll provide the code for the IValueProvider implementation (which should look VERY familiar) and you can use the work we've already done as a reference to create and register the factory: public class RenderingContextValueProvider : IValueProvider { private NameValueCollectionValueProvider _wrappedProvider = null; public RenderingContextValueProvider(ControllerContext controllerContext) { var collection = new NameValueCollection(); var rc = RenderingContext.CurrentOrNull; if (rc != null && rc.Rendering != null) { foreach(var parameter in rc.Rendering.Parameters) { collection.Add(parameter.Key, parameter.Value); } } _wrappedProvider = new NameValueCollectionValueProvider(collection, CultureInfo.InvariantCulture); } public bool ContainsPrefix(string prefix) { return _wrappedProvider.ContainsPrefix(prefix); } public ValueProviderResult GetValue(string key) { return _wrappedProvider.GetValue(key); } } In this post I've discussed the MVC IValueProvider used to map data to controller action method arguments and how this can be integrated into your Sitecore 6.6 MVC solution.

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The Application Architecture Domain

- by Michael Glas

I have been spending a lot of time thinking about Application Architecture in the context of EA. More specifically, as an Enterprise Architect, what do I need to consider when looking at/defining/designing the Application Architecture Domain?There are several definitions of Application Architecture. TOGAF says “The objective here [in Application Architecture] is to define the major kinds of application system necessary to process the data and support the business”. FEA says the Application Architecture “Defines the applications needed to manage the data and support the business functions”.I agree with these definitions. They reflect what the Application Architecture domain does. However, they need to be decomposed to be practical.I find it useful to define a set of views into the Application Architecture domain. These views reflect what an EA needs to consider when working with/in the Applications Architecture domain. These viewpoints are, at a high level:Capability View: This view reflects how applications alignment with business capabilities. It is a super set of the following views when viewed in aggregate. By looking at the Application Architecture domain in terms of the business capabilities it supports, you get a good perspective on how those applications are directly supporting the business.Technology View: The technology view reflects the underlying technology that makes up the applications. Based on the number of rationalization activities I have seen (more specifically application rationalization), the phrase “complexity equals cost” drives the importance of the technology view, especially when attempting to reduce that complexity through standardization type activities. Some of the technology components to be considered are: Software: The application itself as well as the software the application relies on to function (web servers, application servers). Infrastructure: The underlying hardware and network components required by the application and supporting application software. Development: How the application is created and maintained. This encompasses development components that are part of the application itself (i.e. customizable functions), as well as bolt on development through web services, API’s, etc. The maintenance process itself also falls under this view. Integration: The interfaces that the application provides for integration as well as the integrations to other applications and data sources the application requires to function. Type: Reflects the kind of application (mash-up, 3 tiered, etc). (Note: functional type [CRM, HCM, etc.] are reflected under the capability view). Organization View: Organizations are comprised of people and those people use applications to do their jobs. Trying to define the application architecture domain without taking the organization that will use/fund/change it into consideration is like trying to design a car without thinking about who will drive it (i.e. you may end up building a formula 1 car for a family of 5 that is really looking for a minivan). This view reflects the people aspect of the application. It includes: Ownership: Who ‘owns’ the application? This will usually reflect primary funding and utilization but not always. Funding: Who funds both the acquisition/creation as well as the on-going maintenance (funding to create/change/operate)? Change: Who can/does request changes to the application and what process to the follow? Utilization: Who uses the application, how often do they use it, and how do they use it? Support: Which organization is responsible for the on-going support of the application? Information View: Whether or not you subscribe to the view that “information drives the enterprise”, it is a fact that information is critical. The management, creation, and organization of that information are primary functions of enterprise applications. This view reflects how the applications are tied to information (or at a higher level – how the Application Architecture domain relates to the Information Architecture domain). It includes: Access: The application is the mechanism by which end users access information. This could be through a primary application (i.e. CRM application), or through an information access type application (a BI application as an example). Creation: Applications create data in order to provide information to end-users. (I.e. an application creates an order to be used by an end-user as part of the fulfillment process). Consumption: Describes the data required by applications to function (i.e. a product id is required by a purchasing application to create an order. Application Service View: Organizations today are striving to be more agile. As an EA, I need to provide an architecture that supports this agility. One of the primary ways to achieve the required agility in the application architecture domain is through the use of ‘services’ (think SOA, web services, etc.). Whether it is through building applications from the ground up utilizing services, service enabling an existing application, or buying applications that are already ‘service enabled’, compartmentalizing application functions for re-use helps enable flexibility in the use of those applications in support of the required business agility. The applications service view consists of: Services: Here, I refer to the generic definition of a service “a set of related software functionalities that can be reused for different purposes, together with the policies that should control its usage”. Functions: The activities within an application that are not available / applicable for re-use. This view is helpful when identifying duplication functions between applications that are not service enabled. Delivery Model View: It is hard to talk about EA today without hearing the terms ‘cloud’ or shared services. Organizations are looking at the ways their applications are delivered for several reasons, to reduce cost (both CAPEX and OPEX), to improve agility (time to market as an example), etc. From an EA perspective, where/how an application is deployed has impacts on the overall enterprise architecture. From integration concerns to SLA requirements to security and compliance issues, the Enterprise Architect needs to factor in how applications are delivered when designing the Enterprise Architecture. This view reflects how applications are delivered to end-users. The delivery model view consists of different types of delivery mechanisms/deployment options for applications: Traditional: Reflects non-cloud type delivery options. The most prevalent consists of an application running on dedicated hardware (usually specific to an environment) for a single consumer. Private Cloud: The application runs on infrastructure provisioned for exclusive use by a single organization comprising multiple consumers. Public Cloud: The application runs on infrastructure provisioned for open use by the general public. Hybrid: The application is deployed on two or more distinct cloud infrastructures (private, community, or public) that remain unique entities, but are bound together by standardized or proprietary technology that enables data and application portability. While by no means comprehensive, I find that applying these views to the application domain gives a good understanding of what an EA needs to consider when effecting changes to the Application Architecture domain.Finally, the application architecture domain is one of several architecture domains that an EA must consider when developing an overall Enterprise Architecture. The Oracle Enterprise Architecture Framework defines four Primary domains: Business Architecture, Application Architecture, Information Architecture, and Technology Architecture. Each domain links to the others either directly or indirectly at some point. Oracle links them at a high level as follows:Business Capabilities and/or Business Processes (Business Architecture), links to the Applications that enable the capability/process (Applications Architecture – COTS, Custom), links to the Information Assets managed/maintained by the Applications (Information Architecture), links to the technology infrastructure upon which all this runs (Technology Architecture - integration, security, BI/DW, DB infrastructure, deployment model). There are however, times when the EA needs to narrow focus to a particular domain for some period of time. These views help me to do just that.

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Small adventure game

- by Nick Rosencrantz

I'm making a small adventure game where the player can walk through Dungeons and meet scary characters: The whole thing is 20 java classes and I'm making this a standalone frame while it could very well be an applet I don't want to make another applet since I might want to recode this in C/C++ if the game or game engine turns out a success. The engine is the most interesting part of the game, it controls players and computer-controlled characters such as Zombies, Reptile Warriors, Trolls, Necromancers, and other Persons. These persons can sleep or walk around in the game and also pick up and move things. I didn't add many things so I suppose that is the next thing to do is to add things that can get used now that I already added many different types of walking persons. What do you think I should add and do with things in the game? The things I have so far is: package adventure; /** * The data type for things. Subclasses will be create that takes part of the story */ public class Thing { /** * The name of the Thing. */ public String name; /** * @param name The name of the Thing. */ Thing( String name ) { this.name = name; } } public class Scroll extends Thing { Scroll (String name) { super(name); } } class Key extends Thing { Key (String name) { super(name); } } The key is the way to win the game if you figure our that you should give it to a certain person and the scroll can protect you from necromancers and trolls. If I make this game more Dungeons and Dragons-inspired, do you think will be any good? Any other ideas that you think I could use here? The Threadwhich steps time forward and wakes up persons is called simulation. Do you think I could do something more advanced with this class? package adventure; class Simulation extends Thread { private PriorityQueue Eventqueue; Simulation() { Eventqueue = new PriorityQueue(); start(); } public void wakeMeAfter(Wakeable SleepingObject, double time) { Eventqueue.enqueue(SleepingObject, System.currentTimeMillis()+time); } public void run() { while(true) { try { sleep(5); //Sov i en halv sekund if (Eventqueue.getFirstTime() <= System.currentTimeMillis()) { ((Wakeable)Eventqueue.getFirst()).wakeup(); Eventqueue.dequeue(); } } catch (InterruptedException e ) { } } } } And here is the class that makes up the actual world: package adventure; import java.awt.*; import java.net.URL; /** * Subklass to World that builds up the Dungeon World. */ public class DungeonWorld extends World { /** * * @param a Reference to adventure game. * */ public DungeonWorld(Adventure a) { super ( a ); // Create all places createPlace( "Himlen" ); createPlace( "Stairs3" ); createPlace( "IPLab" ); createPlace( "Dungeon3" ); createPlace( "Stairs5" ); createPlace( "C2M2" ); createPlace( "SANS" ); createPlace( "Macsal" ); createPlace( "Stairs4" ); createPlace( "Dungeon2" ); createPlace( "Datorsalen" ); createPlace( "Dungeon");//, "Ljushallen.gif" ); createPlace( "Cola-automaten", "ColaAutomat.gif" ); createPlace( "Stairs2" ); createPlace( "Fable1" ); createPlace( "Dungeon1" ); createPlace( "Kulverten" ); // Create all connections between places connect( "Stairs3", "Stairs5", "Down", "Up" ); connect( "Dungeon3", "SANS", "Down", "Up" ); connect( "Dungeon3", "IPLab", "West", "East" ); connect( "IPLab", "Stairs3", "West", "East" ); connect( "Stairs5", "Stairs4", "Down", "Up" ); connect( "Macsal", "Stairs5", "South", "Norr" ); connect( "C2M2", "Stairs5", "West", "East" ); connect( "SANS", "C2M2", "West", "East" ); connect( "Stairs4", "Dungeon", "Down", "Up" ); connect( "Datorsalen", "Stairs4", "South", "Noth" ); connect( "Dungeon2", "Stairs4", "West", "East" ); connect( "Dungeon", "Stairs2", "Down", "Up" ); connect( "Dungeon", "Cola-automaten", "South", "North" ); connect( "Stairs2", "Kulverten", "Down", "Up" ); connect( "Stairs2", "Fable1", "East", "West" ); connect( "Fable1", "Dungeon1", "South", "North" ); // Add things // --- Add new things here --- getPlace("Cola-automaten").addThing(new CocaCola("Ljummen cola")); getPlace("Cola-automaten").addThing(new CocaCola("Avslagen Cola")); getPlace("Cola-automaten").addThing(new CocaCola("Iskall Cola")); getPlace("Cola-automaten").addThing(new CocaCola("Cola Light")); getPlace("Cola-automaten").addThing(new CocaCola("Cuba Cola")); getPlace("Stairs4").addThing(new Scroll("Scroll")); getPlace("Dungeon3").addThing(new Key("Key")); Simulation sim = new Simulation(); // Load images to be used as appearance-parameter for persons Image studAppearance = owner.loadPicture( "Person.gif" ); Image asseAppearance = owner.loadPicture( "Asse.gif" ); Image trollAppearance = owner.loadPicture( "Loke.gif" ); Image necromancerAppearance = owner.loadPicture( "Necromancer.gif" ); Image skeletonAppearance = owner.loadPicture( "Reptilewarrior.gif" ); Image reptileAppearance = owner.loadPicture( "Skeleton.gif" ); Image zombieAppearance = owner.loadPicture( "Zombie.gif" ); // --- Add new persons here --- new WalkingPerson(sim, this, "Peter", studAppearance); new WalkingPerson(sim, this, "Zombie", zombieAppearance ); new WalkingPerson(sim, this, "Zombie", zombieAppearance ); new WalkingPerson(sim, this, "Skeleton", skeletonAppearance ); new WalkingPerson(sim, this, "John", studAppearance ); new WalkingPerson(sim, this, "Skeleton", skeletonAppearance ); new WalkingPerson(sim, this, "Skeleton", skeletonAppearance ); new WalkingPerson(sim, this, "Skeleton", skeletonAppearance ); new WalkingPerson(sim, this, "Sean", studAppearance ); new WalkingPerson(sim, this, "Reptile", reptileAppearance ); new LabAssistant(sim, this, "Kate", asseAppearance); new LabAssistant(sim, this, "Jenna", asseAppearance); new Troll(sim, this, "Troll", trollAppearance); new Necromancer(sim, this, "Necromancer", necromancerAppearance); } /** * * The place where persons are placed by default * *@return The default place. * */ public Place defaultPlace() { return getPlace( "Datorsalen" ); } private void connect( String p1, String p2, String door1, String door2) { Place place1 = getPlace( p1 ); Place place2 = getPlace( p2 ); place1.addExit( door1, place2 ); place2.addExit( door2, place1 ); } } Thanks

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ASP.NET WebAPI Security 3: Extensible Authentication Framework

- by Your DisplayName here!

In my last post, I described the identity architecture of ASP.NET Web API. The short version was, that Web API (beta 1) does not really have an authentication system on its own, but inherits the client security context from its host. This is fine in many situations (e.g. AJAX style callbacks with an already established logon session). But there are many cases where you don’t use the containing web application for authentication, but need to do it yourself. Examples of that would be token based authentication and clients that don’t run in the context of the web application (e.g. desktop clients / mobile). Since Web API provides a nice extensibility model, it is easy to implement whatever security framework you want on top of it. My design goals were: Easy to use. Extensible. Claims-based. ..and of course, this should always behave the same, regardless of the hosting environment. In the rest of the post I am outlining some of the bits and pieces, So you know what you are dealing with, in case you want to try the code. At the very heart… is a so called message handler. This is a Web API extensibility point that gets to see (and modify if needed) all incoming and outgoing requests. Handlers run after the conversion from host to Web API, which means that handler code deals with HttpRequestMessage and HttpResponseMessage. See Pedro’s post for more information on the processing pipeline. This handler requires a configuration object for initialization. Currently this is very simple, it contains: Settings for the various authentication and credential types Settings for claims transformation Ability to block identity inheritance from host The most important part here is the credential type support, but I will come back to that later. The logic of the message handler is simple: Look at the incoming request. If the request contains an authorization header, try to authenticate the client. If this is successful, create a claims principal and populate the usual places. If not, return a 401 status code and set the Www-Authenticate header. Look at outgoing response, if the status code is 401, set the Www-Authenticate header. Credential type support Under the covers I use the WIF security token handler infrastructure to validate credentials and to turn security tokens into claims. The idea is simple: an authorization header consists of two pieces: the schema and the actual “token”. My configuration object allows to associate a security token handler with a scheme. This way you only need to implement support for a specific credential type, and map that to the incoming scheme value. The current version supports HTTP Basic Authentication as well as SAML and SWT tokens. (I needed to do some surgery on the standard security token handlers, since WIF does not directly support string-ified tokens. The next version of .NET will fix that, and the code should become simpler then). You can e.g. use this code to hook up a username/password handler to the Basic scheme (the default scheme name for Basic Authentication). config.Handler.AddBasicAuthenticationHandler( (username, password) => username == password); You simply have to provide a password validation function which could of course point back to your existing password library or e.g. membership. The following code maps a token handler for Simple Web Tokens (SWT) to the Bearer scheme (the currently favoured scheme name for OAuth2). You simply have to specify the issuer name, realm and shared signature key: config.Handler.AddSimpleWebTokenHandler( "Bearer", http://identity.thinktecture.com/trust, Constants.Realm, "Dc9Mpi3jaaaUpBQpa/4R7XtUsa3D/ALSjTVvK8IUZbg="); For certain integration scenarios it is very useful if your Web API can consume SAML tokens. This is also easily accomplishable. The following code uses the standard WIF API to configure the usual SAMLisms like issuer, audience, service certificate and certificate validation. Both SAML 1.1 and 2.0 are supported. var registry = new ConfigurationBasedIssuerNameRegistry(); registry.AddTrustedIssuer( "d1 c5 b1 25 97 d0 36 94 65 1c e2 64 fe 48 06 01 35 f7 bd db", "ADFS"); var adfsConfig = new SecurityTokenHandlerConfiguration(); adfsConfig.AudienceRestriction.AllowedAudienceUris.Add( new Uri(Constants.Realm)); adfsConfig.IssuerNameRegistry = registry; adfsConfig.CertificateValidator = X509CertificateValidator.None; // token decryption (read from configuration section) adfsConfig.ServiceTokenResolver = FederatedAuthentication.ServiceConfiguration.CreateAggregateTokenResolver(); config.Handler.AddSaml11SecurityTokenHandler("SAML", adfsConfig); Claims Transformation After successful authentication, if configured, the standard WIF ClaimsAuthenticationManager is called to run claims transformation and validation logic. This stage is used to transform the “technical” claims from the security token into application claims. You can either have a separate transformation logic, or share on e.g. with the containing web application. That’s just a matter of configuration. Adding the authentication handler to a Web API application In the spirit of Web API this is done in code, e.g. global.asax for web hosting: protected void Application_Start() { AreaRegistration.RegisterAllAreas(); ConfigureApis(GlobalConfiguration.Configuration); RegisterGlobalFilters(GlobalFilters.Filters); RegisterRoutes(RouteTable.Routes); BundleTable.Bundles.RegisterTemplateBundles(); } private void ConfigureApis(HttpConfiguration configuration) { configuration.MessageHandlers.Add( new AuthenticationHandler(ConfigureAuthentication())); } private AuthenticationConfiguration ConfigureAuthentication() { var config = new AuthenticationConfiguration { // sample claims transformation for consultants sample, comment out to see raw claims ClaimsAuthenticationManager = new ApiClaimsTransformer(), // value of the www-authenticate header, // if not set, the first scheme added to the handler collection is used DefaultAuthenticationScheme = "Basic" }; // add token handlers - see above return config; } You can find the full source code and some samples here. In the next post I will describe some of the samples in the download, and then move on to authorization. HTH

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How to use ULS in SharePoint 2010 for Custom Code Exception Logging?

- by venkatx5

What is ULS in SharePoint 2010? ULS stands for Unified Logging Service which captures and writes Exceptions/Logs in Log File(A Plain Text File with .log extension). SharePoint logs Each and every exceptions with ULS. SharePoint Administrators should know ULS and it's very useful when anything goes wrong. but when you ask any SharePoint 2007 Administrator to check log file then most of them will Kill you. Because read and understand the log file is not so easy. Imagine open a plain text file of 20 MB in NotePad and go thru line by line. Now Microsoft developed a tool "ULS Viewer" to view those Log files in easily readable format. This tools also helps to filter events based on exception priority. You can read on this blog to know in details about ULS Viewer . Where to get ULS Viewer? ULS Viewer is developed by Microsoft and available to download for free. URL : http://code.msdn.microsoft.com/ULSViewer/Release/ProjectReleases.aspx?ReleaseId=3308 Note: Eventhought this tool developed by Microsoft, it's not supported by Microsoft. Means you can't support for this tool from Microsoft and use it on your own Risk. By the way what's the risk in viewing Log Files?! How to use ULS in SharePoint 2010 Custom Code? ULS can be extended to use in user solutions to log exceptions. In Detail, Developer can use ULS to log his own application errors and exceptions on SharePoint Log files. So now all in Single Place (That's why it's called "Unified Logging"). Well in this article I am going to use Waldek's Code (Reference Link). However the article is core and am writing container for that (Basically how to implement the code in Detail). Let's see the steps. Open Visual Studio 2010 -> File -> New Project -> Visual C# -> Windows -> Class Library -> Name : ULSLogger (Make sure you've selected .net Framework 3.5) In Solution Explorer Panel, Rename the Class1.cs to LoggingService.cs Right Click on References -> Add Reference -> Under .Net tab select "Microsoft.SharePoint" Right Click on the Project -> Properties. Select "Signing" Tab -> Check "Sign the Assembly". In the below drop down select <New> and enter "ULSLogger", uncheck the "Protect my key with a Password" option. Now copy the below code and paste. (Or Just refer.. :-) ) using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.SharePoint; using Microsoft.SharePoint.Administration; using System.Runtime.InteropServices; namespace ULSLogger { public class LoggingService : SPDiagnosticsServiceBase { public static string vsDiagnosticAreaName = "Venkats SharePoint Logging Service"; public static string CategoryName = "vsProject"; public static uint uintEventID = 700; // Event ID private static LoggingService _Current; public static LoggingService Current { get { if (_Current == null) { _Current = new LoggingService(); } return _Current; } }private LoggingService() : base("Venkats SharePoint Logging Service", SPFarm.Local) {}protected override IEnumerable<SPDiagnosticsArea> ProvideAreas() { List<SPDiagnosticsArea> areas = new List<SPDiagnosticsArea> { new SPDiagnosticsArea(vsDiagnosticAreaName, new List<SPDiagnosticsCategory> { new SPDiagnosticsCategory(CategoryName, TraceSeverity.Medium, EventSeverity.Error) }) }; return areas; }public static string LogErrorInULS(string errorMessage) { string strExecutionResult = "Message Not Logged in ULS. "; try { SPDiagnosticsCategory category = LoggingService.Current.Areas[vsDiagnosticAreaName].Categories[CategoryName]; LoggingService.Current.WriteTrace(uintEventID, category, TraceSeverity.Unexpected, errorMessage); strExecutionResult = "Message Logged"; } catch (Exception ex) { strExecutionResult += ex.Message; } return strExecutionResult; }public static string LogErrorInULS(string errorMessage, TraceSeverity tsSeverity) { string strExecutionResult = "Message Not Logged in ULS. "; try { SPDiagnosticsCategory category = LoggingService.Current.Areas[vsDiagnosticAreaName].Categories[CategoryName]; LoggingService.Current.WriteTrace(uintEventID, category, tsSeverity, errorMessage); strExecutionResult = "Message Logged"; } catch (Exception ex) { strExecutionResult += ex.Message; } return strExecutionResult; } } } Just build the solution and it's ready to use now. This ULS solution can be used in SharePoint Webparts or Console Application. Lets see how to use it in a Console Application. SharePoint Server 2010 must be installed in the same Server or the application must be hosted in SharPoint Server 2010 environment. The console application must be set to "x64" Platform target. Create a New Console Application. (Visual Studio -> File -> New Project -> C# -> Windows -> Console Application) Right Click on References -> Add Reference -> Under .Net tab select "Microsoft.SharePoint" Open Program.cs add "using Microsoft.SharePoint.Administration;" Right Click on References -> Add Reference -> Under "Browse" tab select the "ULSLogger.dll" which we created first. (Path : ULSLogger\ULSLogger\bin\Debug\) Right Click on Project -> Properties -> Select "Build" Tab -> Under "Platform Target" option select "x64". Open the Program.cs and paste the below code. using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.SharePoint.Administration; using ULSLogger; namespace ULSLoggerClient { class Program { static void Main(string[] args) { Console.WriteLine("ULS Logging Started."); string strResult = LoggingService.LogErrorInULS("My Application is Working Fine."); Console.WriteLine("ULS Logging Info. Result : " + strResult); string strResult = LoggingService.LogErrorInULS("My Application got an Exception.", TraceSeverity.High); Console.WriteLine("ULS Logging Waring Result : " + strResult); Console.WriteLine("ULS Logging Completed."); Console.ReadLine(); } } } Just build the solution and execute. It'll log the message on the log file. Make sure you are using Farm Administrator User ID. You can play with Message and TraceSeverity as required. Now Open ULS Viewer -> File -> Open From -> ULS -> Select First Option to open the default ULS Log. It's Uls RealTime and will show all log entries in readable table format. Right Click on a row and select "Filter By This Item". Select "Event ID" and enter value "700" that we used in the application. Click Ok and now you'll see the Exceptions/Logs which logged by our application. If you want to see High Priority Messages only then Click Icons except Red Cross Icon on the Toolbar. The tooltip will tell what's the icons used for.

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Inventory Management concepts in XNA game

- by user1332755

I am trying to code the inventory system in my first real game so I have very little experience in both c# and game engine development. Basically, I need some general guidance and tips with how to structure and organize these sorts of systems. Please tell me if I am on the right track or not before I get too deep into making some badly structured system. It's fine if you don't feel like looking through my code, suggestions about general structure would also be appreciated. What I am aiming to end up with is some sort of system like Minecraft or Terraria. It must include: main inventory GUI (items can be dragged and placed in whatever slot desired Itembar outside of the main inventory which can be assigned to certain items the ability to use items from either location So far, I have 4 main classes: Inventory holds the general info and methods, inventoryslot holds info for individual slots, Itembar holds all info and methods for itself, and finally, ItemManager to manage interactions between the two and hold a master list of items. So far, my itembar works perfectly and interacts well with mousedragging items into and out of it as well as activating the item effect. Here is the code I have so far: (there is a lot but I will try to keep it relevant) This is the code for the itembar on the main screen: class Itembar { public Texture2D itembarfull, iSelected; public static Rectangle itembar = new Rectangle(5, 218, 40, 391); public Rectangle box1 = new Rectangle(itembar.X, 218, 40, 40); //up to 10 Rectangles for each slot public int Selected = 0; private ItemManager manager; public Itembar(Texture2D texture, Texture2D texture3, ItemManager mann) { itembarfull = texture; iSelected = texture3; manager = mann; } public void Update(GameTime gametime) { } public void Draw(SpriteBatch spriteBatch) { spriteBatch.Draw( itembarfull, new Vector2 (itembar.X, itembar.Y), null, Color.White, 0.0f, Vector2.Zero, 1.0f, SpriteEffects.None, 1.0f); if (Selected == 1) spriteBatch.Draw(iSelected, new Rectangle(box1.X-3, box1.Y-3, box1.Width+6, box1.Height+6), Color.White); //goes up to 10 slots } public int Box1Query() { foreach (Item item in manager.items) { if(box1.Contains(item.BoundingBox)) return manager.items.IndexOf(item); } return 999; } //10 different box queries It is working fine right now. I just put an Item in there and the box will query things like the item's effects, stack number, consumable or not etc...This one is basically almost complete. Here is the main inventory class: class Inventory { public bool isActive; public List<Rectangle> mainSlots = new List<Rectangle>(24); public List<InventorySlot> mainSlotscheck = new List<InventorySlot>(24); public static Rectangle inv = new Rectangle(841, 469, 156, 231); public Rectangle invfull = new Rectangle(inv.X, inv.Y, inv.Width, inv.Height); public Rectangle inv1 = new Rectangle(inv.X + 4, inv.Y +3, 32, 32); //goes up to inv24 resulting in a 6x4 grid of Rectangles public Inventory() { mainSlots.Add(inv1); mainSlots.Add(inv2); mainSlots.Add(inv3); mainSlots.Add(inv4); //goes up to 24 foreach (Rectangle slot in mainSlots) mainSlotscheck.Add(new InventorySlot(slot)); } //update and draw methods are empty because im not too sure what to put there public int LookforfreeSlot() { int slotnumber = 999; for (int x = 0; x < mainSlots.Count; x++) { if (mainSlotscheck[x].isFree) { slotnumber = x; break; } } return slotnumber; } } } LookforFreeSlot() method is meant to be called when I do AddtoInventory(). I'm kinda stumped about what other things I need to put in this class. Here is the inventorySlot class: (its main purpose is to check the bool "isFree" to see whether or not something already occupies the slot. But i guess it can also do other stuff like get item info.) class InventorySlot { public int X, Y; public int Width = 32, Height = 32; public Vector2 Position; public int slotnumber; public bool free = true; public int? content = null; public bool isFree { get { return free; } set { free = value; } } public InventorySlot(Rectangle slot) { slot = new Rectangle(X, Y, Width, Height); } } } Finally, here is the ItemManager (I am omitting the master list because it is too long) class ItemManager { public List<Item> items = new List<Item>(20); public List<Item> inventory1 = new List<Item>(24); public List<Item> inventory2 = new List<Item>(24); public List<Item> inventory3 = new List<Item>(24); public List<Item> inventory4 = new List<Item>(24); public Texture2D icon, filta; private Rectangle msRect; MouseState mouseState; public int ISelectedIndex; Inventory inventory; SpriteFont font; public void GenerateItems() { items.Add(new Item(new Rectangle(0, 0, 32, 32), icon, font)); items[0].name = "Grass Chip"; items[0].itemID = 0; items[0].consumable = true; items[0].stackable = true; items[0].maxStack = 99; items.Add(new Item(new Rectangle(32, 0, 32, 32), icon, font)); //master list continues. it will generate all items in the game; } public ItemManager(Inventory inv, Texture2D itemsheet, Rectangle mouseRectt, MouseState ms, Texture2D fil, SpriteFont f) { icon = itemsheet; msRect = mouseRectt; filta = fil; mouseState = ms; inventory = inv; font = f; } //once again, no update or draw public void mousedrag() { items[0].DestinationRect = new Rectangle (msRect.X, msRect.Y, 32, 32); items[0].dragging = true; } public void AddtoInventory(Item item) { int index = inventory.LookforfreeSlot(); if (index == 999) return; item.DestinationRect = inventory.mainSlots[index]; inventory.mainSlotscheck[index].content = item.itemID; inventory.mainSlotscheck[index].isFree = false; item.IsActive = true; } } } The mousedrag works pretty well. AddtoInventory doesn't work because LookforfreeSlot doesn't work. Relevant code from the main program: When I want to add something to the main inventory, I do something like this: foreach (Particle ether in ether1.ethers) { if (ether.isCollected) itemmanager.AddtoInventory(itemmanager.items[14]); } This turned out to be much longer than I had expected :( But I hope someone is interested enough to comment.

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Turning on collision crashes game

- by MomentumGaming

I am getting a null pointer excecption to both my sprite and level. I am working on my mob class, and when I try to move him and the move function is called, the game crashes after checking collision with a null pointer excecption. Taking out the one line that actually checks if the tile located in front of it fixes the problem. Also, if i keep collision ON but don't move the position of the mob (the spider) the game works fine. I will have collision, and the spider appears on the screen, only problem is, getting it to move causes this nasty error that i just can't fix. true Exception in thread "Display" java.lang.NullPointerException at com.apcompsci.game.entity.mob.Mob.collision(Mob.java:67) at com.apcompsci.game.entity.mob.Mob.move(Mob.java:38) at com.apcompsci.game.entity.mob.spider.update(spider.java:58) at com.apcompsci.game.level.Level.update(Level.java:55) at com.apcompsci.game.Game.update(Game.java:128) at com.apcompsci.game.Game.run(Game.java:106) at java.lang.Thread.run(Unknown Source) Here is my renderMob mehtod: public void renderMob(int xp,int yp,Sprite sprite,int flip) { xp -= xOffset; yp-=yOffset; for(int y = 0; y<32; y++) { int ya = y + yp; int ys = y; if(flip == 2||flip == 3)ys = 31-y; for(int x = 0; x<32; x++) { int xa = x + xp; int xs = x; if(flip == 1||flip == 3)xs = 31-x; if(xa < -32 || xa >=width || ya<0||ya>=height) break; if(xa<0) xa =0; int col = sprite.pixels[xs+ys*32]; if(col!= 0x000000) pixels[xa+ya*width] = col; } } } My spider class which determines the sprite and where I control movement, also rendering the spider onto the screen, when I increment ya to move the sprite, I get the crash, but without ya++, it runs flawlessly with a spider sprite on screen: package com.apcompsci.game.entity.mob; import com.apcompsci.game.entity.mob.Mob.Direction; import com.apcompsci.game.graphics.Screen; import com.apcompsci.game.graphics.Sprite; import com.apcompsci.game.level.Level; public class spider extends Mob{ Direction dir; private Sprite sprite; private boolean walking; public spider(int x, int y) { this.x = x <<4; this.y = y <<4; sprite = sprite.spider_forward; } public void update() { int xa = 0, ya = 0; ya++; if(ya<0) { sprite = sprite.spider_forward; dir = Direction.UP; } if(ya>0) { sprite = sprite.spider_back; dir = Direction.DOWN; } if(xa<0) { sprite = sprite.spider_side; dir = Direction.LEFT; } if(xa>0) { sprite = sprite.spider_side; dir = Direction.LEFT; } if(xa!= 0 || ya!= 0) { System.out.println("true"); move(xa,ya); walking = true; } else{ walking = false; } } public void render(Screen screen) { screen.renderMob(x, y, sprite, 0); } } This is th mob class that contains the move() method that is called in the spider class above. This move method calls the collision method. tile and sprite comes up null in the debugger: package com.apcompsci.game.entity.mob; import java.util.ArrayList; import java.util.List; import com.apcompsci.game.entity.Entity; import com.apcompsci.game.entity.projectile.DemiGodProjectile; import com.apcompsci.game.entity.projectile.Projectile; import com.apcompsci.game.graphics.Sprite; public class Mob extends Entity{ protected Sprite sprite; protected boolean moving = false; protected enum Direction { UP,DOWN,LEFT,RIGHT } protected Direction dir; public void move(int xa,int ya) { if(xa != 0 && ya != 0) { move(xa,0); move(0,ya); return; } if(xa>0) dir = Direction.RIGHT; if(xa<0) dir = Direction.LEFT; if(ya>0)dir = Direction.DOWN; if(ya<0)dir = Direction.UP; if(!collision(xa,ya)){ x+= xa; y+=ya; } } public void update() { } public void shoot(int x, int y, double dir) { //dir = Math.toDegrees(dir); Projectile p = new DemiGodProjectile(x, y,dir); level.addProjectile(p); } public boolean collision(int xa,int ya) { boolean solid = false; for(int c = 0; c<4; c++) { int xt = ((x+xa) + c % 2 * 14 - 8 )/16; int yt = ((y+ya) + c / 2 * 12 +3 )/16; if(level.getTile(xt, yt).solid()) solid = true; } return solid; } public void render() { } } Finally, here is the method in which i call the add() method for the spider to add it to the level: protected void loadLevel(String path) { try{ BufferedImage image = ImageIO.read(SpawnLevel.class.getResource(path)); int w = width =image.getWidth(); int h = height = image.getHeight(); tiles = new int[w*h]; image.getRGB(0, 0, w,h, tiles,0, w); } catch(IOException e){ e.printStackTrace(); System.out.println("Exception! Could not load level file!"); } add(new spider(20,45)); } I don't think i need to include the level class but just in case, I have provided a gistHub link for better context. It contains all of the full classes listed above , plus my entity class and maybe another. Thanks for the help if you decide to do so, much appreciated! Also, please tell me if i'm in the wrong section of stackeoverflow, i figured that since this is the gamign section that it belonged but debugging code normally goes into the general section.

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Emtel Knowledge Series - Q2/2014

From Cyber Island to Smart Mauritius Cyber Island? Smart Mauritius? - What is Emtel talking about? "With the majority of the population living in urban environments today, the concept of "Smart Cities" has become an urgent necessity. "Smart Cities" refer to an urban transformation which, by using latest ICT technologies makes cities more efficient. Many Governments are setting out ambitious plans to build the cities of the future based on massive connectivity, high bandwidth communications, intelligent sensors and analysis of huge volumes of data. Various researches have shown four key enablers for smart city success - Government leadership, suitable technology infrastructure, solid public-private partnerships and engaged citizens. It is around these enabling factors that telecoms companies can play a vital role in assisting governments to deliver on the smart city vision." The Emtel Knowledge Series goes in compliance with Emtel's 25th anniversary celebrations throughout the year and the master of ceremony, Kim Andersen, mentioned that there will be more upcoming events on a quarterly base. As a representative of the Mauritius Software Craftsmanship Community (MSCC) there was absolutely no hesitation to join in again. Following my visit to the first Emtel Knowledge Series workshop back in February this year, it was great to have another opportunity to meet and exchange with technology experts. But quite frankly what is it with those buzz words... As far as I remember and how it was mentioned "Cyber Island" is an old initiative from around 2005/2006 which has been refreshed in 2010. It implies the empowerment of Information & Communication Technologies (ICT) as an essential factor of growth by the government here in Mauritius. Actually, the first promotional period of Cyber Island brought me here but that's another story. The venue and its own problems Like last time the event was organised and held at the Conference Hall at Cyber Tower I in Ebene. As I've been working there for some years, I know about the frustrating situation of finding a proper parking. So, does Smart Island include better solutions for the search of parking spaces? Maybe, let's see whether I will be able to answer that question at the end of the article. Anyway, after circling around the tower almost two times, I finally got a decent space to put the car, without risking to get a ticket or damage actually. International speakers and their experience Once again, Emtel did a great job to get international expertise onto the stage to share their experience and vision on this kind of embarkment. Personally, I really appreciated the fact they were speakers of global reach and could provide own-experience knowledge. Johan Gott spoke about the fundamental change that the Swedish government ignited in order to move their society and workers' environment away from heavy industry towards a knowledge-based approach. Additionally, we spoke about the effort and transformation of New York City into a greener and more efficient Smart City. Given modern technology he also advised that any kind of available Big Data should be opened to the general public - this openness would provide a playground for anyone to garner new ideas and most probably solid solutions of which no one else thought about before. Emtel Knowledge Series on moving from Cyber Island to Smart Mauritus Later during the afternoon that exact statement regarding openness to and transparency of government-owned Big Data has been emphasised again by the Danish speaker Kim Andersen and his former colleague Mika Jantunen from Finland. Mika continued to underline the important role of the government to provide a solid foundation for a knowledge-based society and mentioned that Finnish citizens have a constitutional right to broadband connectivity. Next to free higher (tertiary) education Finland already produced a good number of innovations, among them are: First country to grant voting rights to women Free higher education Constitutional right to broadband connectivity Nokia Linux Angry Birds Sauna and others... General access to internet via broadband and/or mobile connectivity is surely a key factor towards Smart Cities, or better said Smart Mauritius given the area dimensions and size of population. CTO Paul Valette gave the audience a brief overview of the essential role that Emtel will have to move Mauritius forward towards a knowledge-based and innovation-driven environment for its citizen. What I have seen looks really promising and with recently published information that Mauritians have 127% of mobile capacity - meaning more than 1 mobile, smartphone or tablet per person - it will be crucial to have the right infrastructure for these connected devices. How would it be possible to achieve a knowledge-based society? YouTube to the rescue!Seriously, gaining more knowledge will require to have fast access to educational course material as explained by Dr Kaviraj Sukon, General Director of the Open University of Mauritius. According to him a good number of high-profile universities in the world have opened their course libraries to the general public, among them EDX, Coursera and Open University. Nowadays, you're actually able and enabled to learn for and earn a BSc or even MSc certification on your own pace - no need to attend classed on campus. It was really impressive to see the number of available hours - more than enough for a life-long learning experience! {loadposition content_adsense} Networking in the name of MSCC As briefly mentioned above I was about to combine two approaches for this workshop. Of course, getting latest information and updates on Emtel services available, especially for my business here on the west coast of the island, but also to meet and greet new people for the MSCC. And I think it was very positive on both sides. Let me quickly describe some of the key aspects that happened during the day: Met with Arnaud Meslier and Kellie, both Microsoft to swap latest information on IT events. Hereby, I got an invite to Microsoft Windows Phone 8.1 Dev Camp. Got in touch with Arvin Lockee, Emtel to check our options to meet with the data team, and seizing the opportunity to have a visiting tour at the Emtel Data Centre. Had a great chat with Avinash Meetoo, Knowledge 7, Kim Andersen and Mika Jantunen about the situation of teaching and learning in general and specifically in the private sector here in Mauritius. Additionally, a number of various other interesting chats... Once again, I'm catching up on a couple of business cards in order to provide more background information about the MSCC, and to create a better awareness of MSCC within the local IT businesses. There is more to come soon! Resume of the day The number of attendees during this event has been doubled or even tripled this time. The whole organisation has been improved massively and the combination of presentation and summarizing panel discussions was better than during the previous workshop back in February. Overall, once again a well-organised workshop and I'm already looking forward to join the next workshop in Q3. Update End of July we finally managed to visit the Emtel Data Centre in Arsenal. It was an interesting opportunity for some of our MSCC members.

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MapReduce in DryadLINQ and PLINQ

- by JoshReuben

MapReduce See http://en.wikipedia.org/wiki/Mapreduce The MapReduce pattern aims to handle large-scale computations across a cluster of servers, often involving massive amounts of data. "The computation takes a set of input key/value pairs, and produces a set of output key/value pairs. The developer expresses the computation as two Func delegates: Map and Reduce. Map - takes a single input pair and produces a set of intermediate key/value pairs. The MapReduce function groups results by key and passes them to the Reduce function. Reduce - accepts an intermediate key I and a set of values for that key. It merges together these values to form a possibly smaller set of values. Typically just zero or one output value is produced per Reduce invocation. The intermediate values are supplied to the user's Reduce function via an iterator." the canonical MapReduce example: counting word frequency in a text file. MapReduce using DryadLINQ see http://research.microsoft.com/en-us/projects/dryadlinq/ and http://connect.microsoft.com/Dryad DryadLINQ provides a simple and straightforward way to implement MapReduce operations. This The implementation has two primary components: A Pair structure, which serves as a data container. A MapReduce method, which counts word frequency and returns the top five words. The Pair Structure - Pair has two properties: Word is a string that holds a word or key. Count is an int that holds the word count. The structure also overrides ToString to simplify printing the results. The following example shows the Pair implementation. public struct Pair { private string word; private int count; public Pair(string w, int c) { word = w; count = c; } public int Count { get { return count; } } public string Word { get { return word; } } public override string ToString() { return word + ":" + count.ToString(); } } The MapReduce function that gets the results. the input data could be partitioned and distributed across the cluster. 1. Creates a DryadTable<LineRecord> object, inputTable, to represent the lines of input text. For partitioned data, use GetPartitionedTable<T> instead of GetTable<T> and pass the method a metadata file. 2. Applies the SelectMany operator to inputTable to transform the collection of lines into collection of words. The String.Split method converts the line into a collection of words. SelectMany concatenates the collections created by Split into a single IQueryable<string> collection named words, which represents all the words in the file. 3. Performs the Map part of the operation by applying GroupBy to the words object. The GroupBy operation groups elements with the same key, which is defined by the selector delegate. This creates a higher order collection, whose elements are groups. In this case, the delegate is an identity function, so the key is the word itself and the operation creates a groups collection that consists of groups of identical words. 4. Performs the Reduce part of the operation by applying Select to groups. This operation reduces the groups of words from Step 3 to an IQueryable<Pair> collection named counts that represents the unique words in the file and how many instances there are of each word. Each key value in groups represents a unique word, so Select creates one Pair object for each unique word. IGrouping.Count returns the number of items in the group, so each Pair object's Count member is set to the number of instances of the word. 5. Applies OrderByDescending to counts. This operation sorts the input collection in descending order of frequency and creates an ordered collection named ordered. 6. Applies Take to ordered to create an IQueryable<Pair> collection named top, which contains the 100 most common words in the input file, and their frequency. Test then uses the Pair object's ToString implementation to print the top one hundred words, and their frequency. public static IQueryable<Pair> MapReduce( string directory, string fileName, int k) { DryadDataContext ddc = new DryadDataContext("file://" + directory); DryadTable<LineRecord> inputTable = ddc.GetTable<LineRecord>(fileName); IQueryable<string> words = inputTable.SelectMany(x => x.line.Split(' ')); IQueryable<IGrouping<string, string>> groups = words.GroupBy(x => x); IQueryable<Pair> counts = groups.Select(x => new Pair(x.Key, x.Count())); IQueryable<Pair> ordered = counts.OrderByDescending(x => x.Count); IQueryable<Pair> top = ordered.Take(k); return top; } To Test: IQueryable<Pair> results = MapReduce(@"c:\DryadData\input", "TestFile.txt", 100); foreach (Pair words in results) Debug.Print(words.ToString()); Note: DryadLINQ applications can use a more compact way to represent the query: return inputTable .SelectMany(x => x.line.Split(' ')) .GroupBy(x => x) .Select(x => new Pair(x.Key, x.Count())) .OrderByDescending(x => x.Count) .Take(k); MapReduce using PLINQ The pattern is relevant even for a single multi-core machine, however. We can write our own PLINQ MapReduce in a few lines. the Map function takes a single input value and returns a set of mapped values àLINQ's SelectMany operator. These are then grouped according to an intermediate key à LINQ GroupBy operator. The Reduce function takes each intermediate key and a set of values for that key, and produces any number of outputs per key à LINQ SelectMany again. We can put all of this together to implement MapReduce in PLINQ that returns a ParallelQuery<T> public static ParallelQuery<TResult> MapReduce<TSource, TMapped, TKey, TResult>( this ParallelQuery<TSource> source, Func<TSource, IEnumerable<TMapped>> map, Func<TMapped, TKey> keySelector, Func<IGrouping<TKey, TMapped>, IEnumerable<TResult>> reduce) { return source .SelectMany(map) .GroupBy(keySelector) .SelectMany(reduce); } the map function takes in an input document and outputs all of the words in that document. The grouping phase groups all of the identical words together, such that the reduce phase can then count the words in each group and output a word/count pair for each grouping: var files = Directory.EnumerateFiles(dirPath, "*.txt").AsParallel(); var counts = files.MapReduce( path => File.ReadLines(path).SelectMany(line => line.Split(delimiters)), word => word, group => new[] { new KeyValuePair<string, int>(group.Key, group.Count()) });

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SDL_BlitSurface segmentation fault (surfaces aren't null)

- by Trollkemada

My app is crashing on SDL_BlitSurface() and i can't figure out why. I think it has something to do with my static object. If you read the code you'll why I think so. This happens when the limits of the map are reached, i.e. (iwidth || jheight). This is the code: Map.cpp (this render) Tile const * Map::getTyle(int i, int j) const { if (i >= 0 && j >= 0 && i < width && j < height) { return data[i][j]; } else { return &Tile::ERROR_TYLE; // This makes SDL_BlitSurface (called later) crash //return new Tile(TileType::ERROR); // This works with not problem (but is memory leak, of course) } } void Map::render(int x, int y, int width, int height) const { //DEBUG("(Rendering...) x: "<<x<<", y: "<<y<<", width: "<<width<<", height: "<<height); int firstI = x / TileType::PIXEL_PER_TILE; int firstJ = y / TileType::PIXEL_PER_TILE; int lastI = (x+width) / TileType::PIXEL_PER_TILE; int lastJ = (y+height) / TileType::PIXEL_PER_TILE; // The previous integer division rounds down when dealing with positive values, but it rounds up // negative values. This is a fix for that (We need those values always rounded down) if (firstI < 0) { firstI--; } if (firstJ < 0) { firstJ--; } const int firstX = x; const int firstY = y; SDL_Rect srcRect; SDL_Rect dstRect; for (int i=firstI; i <= lastI; i++) { for (int j=firstJ; j <= lastJ; j++) { if (i*TileType::PIXEL_PER_TILE < x) { srcRect.x = x % TileType::PIXEL_PER_TILE; srcRect.w = TileType::PIXEL_PER_TILE - (x % TileType::PIXEL_PER_TILE); dstRect.x = i*TileType::PIXEL_PER_TILE + (x % TileType::PIXEL_PER_TILE) - firstX; } else if (i*TileType::PIXEL_PER_TILE >= x + width) { srcRect.x = 0; srcRect.w = x % TileType::PIXEL_PER_TILE; dstRect.x = i*TileType::PIXEL_PER_TILE - firstX; } else { srcRect.x = 0; srcRect.w = TileType::PIXEL_PER_TILE; dstRect.x = i*TileType::PIXEL_PER_TILE - firstX; } if (j*TileType::PIXEL_PER_TILE < y) { srcRect.y = 0; srcRect.h = TileType::PIXEL_PER_TILE - (y % TileType::PIXEL_PER_TILE); dstRect.y = j*TileType::PIXEL_PER_TILE + (y % TileType::PIXEL_PER_TILE) - firstY; } else if (j*TileType::PIXEL_PER_TILE >= y + height) { srcRect.y = y % TileType::PIXEL_PER_TILE; srcRect.h = y % TileType::PIXEL_PER_TILE; dstRect.y = j*TileType::PIXEL_PER_TILE - firstY; } else { srcRect.y = 0; srcRect.h = TileType::PIXEL_PER_TILE; dstRect.y = j*TileType::PIXEL_PER_TILE - firstY; } SDL::YtoSDL(dstRect.y, srcRect.h); SDL_BlitSurface(getTyle(i,j)->getType()->getSurface(), &srcRect, SDL::getScreen(), &dstRect); // <-- Crash HERE /*DEBUG("i = "<<i<<", j = "<<j); DEBUG("srcRect.x = "<<srcRect.x<<", srcRect.y = "<<srcRect.y<<", srcRect.w = "<<srcRect.w<<", srcRect.h = "<<srcRect.h); DEBUG("dstRect.x = "<<dstRect.x<<", dstRect.y = "<<dstRect.y);*/ } } } Tile.h #ifndef TILE_H #define TILE_H #include "TileType.h" class Tile { private: TileType const * type; public: static const Tile ERROR_TYLE; Tile(TileType const * t); ~Tile(); TileType const * getType() const; }; #endif Tile.cpp #include "Tile.h" const Tile Tile::ERROR_TYLE(TileType::ERROR); Tile::Tile(TileType const * t) : type(t) {} Tile::~Tile() {} TileType const * Tile::getType() const { return type; } TileType.h #ifndef TILETYPE_H #define TILETYPE_H #include "SDL.h" #include "DEBUG.h" class TileType { protected: TileType(); ~TileType(); public: static const int PIXEL_PER_TILE = 30; static const TileType * ERROR; static const TileType * AIR; static const TileType * SOLID; virtual SDL_Surface * getSurface() const = 0; virtual bool isSolid(int x, int y) const = 0; }; #endif ErrorTyle.h #ifndef ERRORTILE_H #define ERRORTILE_H #include "TileType.h" class ErrorTile : public TileType { friend class TileType; private: ErrorTile(); mutable SDL_Surface * surface; static const char * FILE_PATH; public: SDL_Surface * getSurface() const; bool isSolid(int x, int y) const ; }; #endif ErrorTyle.cpp (The surface can't be loaded when building the object, because it is a static object and SDL_Init() needs to be called first) #include "ErrorTile.h" const char * ErrorTile::FILE_PATH = ("C:\\error.bmp"); ErrorTile::ErrorTile() : TileType(), surface(NULL) {} SDL_Surface * ErrorTile::getSurface() const { if (surface == NULL) { if (SDL::isOn()) { surface = SDL::loadAndOptimice(ErrorTile::FILE_PATH); if (surface->w != TileType::PIXEL_PER_TILE || surface->h != TileType::PIXEL_PER_TILE) { WARNING("Bad tile surface size"); } } else { ERROR("Trying to load a surface, but SDL is not on"); } } if (surface == NULL) { // This if doesn't get called, so surface != NULL ERROR("WTF? Can't load surface :\\"); } return surface; } bool ErrorTile::isSolid(int x, int y) const { return true; }

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Attaching a Command to the WP7 Application Bar.

- by mbcrump

One of the biggest problems that I’ve seen with people creating WP7 applications is how do you bind the application bar to a Relay Command. If your using MVVM then this is particular important. Let’s examine the code that one might add to start with. <phone:PhoneApplicationPage.ApplicationBar> <shell:ApplicationBar IsVisible="True" IsMenuEnabled="True"> <shell:ApplicationBarIconButton x:Name="appbar_button1" IconUri="/icons/appbar.questionmark.rest.png" Text="About"> <i:Interaction.Triggers> <i:EventTrigger EventName="Click"> <GalaSoft_MvvmLight_Command:EventToCommand Command="{Binding DisplayAbout, Mode=OneWay}" /> </i:EventTrigger> </i:Interaction.Triggers> </shell:ApplicationBarIconButton> <shell:ApplicationBar.MenuItems> <shell:ApplicationBarMenuItem x:Name="menuItem1" Text="MenuItem 1"></shell:ApplicationBarMenuItem> <shell:ApplicationBarMenuItem x:Name="menuItem2" Text="MenuItem 2"></shell:ApplicationBarMenuItem> </shell:ApplicationBar.MenuItems> </shell:ApplicationBar> </phone:PhoneApplicationPage.ApplicationBar> Everything looks right. But we quickly notice that we have a squiggly line under our Interaction.Triggers. The problem is that the object is not a FrameworkObject. This same code would have worked perfect if this were a normal button. OK. Point has been proved. Let’s make the ApplicationBar support Commands. So, go ahead and create a new project using MVVM Light. If you want to check out the source and work along side this tutorial then click here. 7 Easy Steps to have binding on the Application Bar using MVVM Light (I might add that you don’t have to use MVVM Light to get this functionality, I just prefer it.) 1) Download MVVM Light if you don’t already have it and install the project templates. It is available at http://mvvmlight.codeplex.com/. 2) Click File-New Project and navigate to Silverlight for Windows Phone. Make sure you use the MVVM Light (WP7) Template. 3) Now that we have our project setup and ready to go let’s download a wrapper created by Nicolas Humann here, it is called Phone7.Fx. After you download it then extract it somewhere that you can find it. This wrapper will make our application bar/menu item bindable. 4) Right click References inside your WP7 project and add the .dll file to your project. 5) In your MainPage.xaml you will need to add the proper namespace to it. Don’t forget to build your project afterwards. xmlns:Preview="clr-namespace:Phone7.Fx.Preview;assembly=Phone7.Fx.Preview" 6) Now you can add the BindableAppBar to your MainPage.xaml with a few lines of code. <Preview:BindableApplicationBar x:Name="AppBar" BarOpacity="1.0" > <Preview:BindableApplicationBarIconButton Command="{Binding DisplayAbout}" IconUri="/icons/appbar.questionmark.rest.png" Text="About" /> <Preview:BindableApplicationBar.MenuItems> <Preview:BindableApplicationBarMenuItem Text="Settings" Command="{Binding InputBox}" /> </Preview:BindableApplicationBar.MenuItems> </Preview:BindableApplicationBar> So your final MainPage.xaml will look similar to this: NOTE: The AppBar will be located inside of the Grid using this wrapper.  <Grid x:Name="LayoutRoot" Background="Transparent"> <Grid.RowDefinitions> <RowDefinition Height="Auto" /> <RowDefinition Height="*" /> </Grid.RowDefinitions>  <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="24,24,0,12"> <TextBlock x:Name="ApplicationTitle" Text="{Binding ApplicationTitle}" Style="{StaticResource PhoneTextNormalStyle}" /> <TextBlock x:Name="PageTitle" Text="{Binding PageName}" Margin="-3,-8,0,0" Style="{StaticResource PhoneTextTitle1Style}" /> </StackPanel>  <Grid x:Name="ContentGrid" Grid.Row="1"> <TextBlock Text="{Binding Welcome}" Style="{StaticResource PhoneTextNormalStyle}" HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="40" /> </Grid> <Preview:BindableApplicationBar x:Name="AppBar" BarOpacity="1.0" > <Preview:BindableApplicationBarIconButton Command="{Binding DisplayAbout}" IconUri="/icons/appbar.questionmark.rest.png" Text="About" /> <Preview:BindableApplicationBar.MenuItems> <Preview:BindableApplicationBarMenuItem Text="Settings" Command="{Binding InputBox}" /> </Preview:BindableApplicationBar.MenuItems> </Preview:BindableApplicationBar> </Grid> 7) Let’s go ahead and create the RelayCommands and write them up to a MessageBox by editing our MainViewModel.cs file. public class MainViewModel : ViewModelBase { public string ApplicationTitle { get { return "MVVM LIGHT"; } } public string PageName { get { return "My page:"; } } public string Welcome { get { return "Welcome to MVVM Light"; } } public RelayCommand DisplayAbout { get; private set; } public RelayCommand InputBox { get; private set; } /// <summary> /// Initializes a new instance of the MainViewModel class. /// </summary> public MainViewModel() { if (IsInDesignMode) { // Code runs in Blend --> create design time data. } else { DisplayAbout = new RelayCommand(() => { MessageBox.Show("About box called!"); }); InputBox = new RelayCommand(() => { MessageBox.Show("settings button called"); }); } } If you run the project now you should get something similar to this (notice the AppBar at the bottom): Now if you hit the question mark then you will get the following MessageBox: The MenuItem works as well so for Settings: As you can see, its pretty easy to add a Command to the ApplicationBar/MenuItem. If you want to look through the full source code then click here. Subscribe to my feed

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Protecting Cookies: Once and For All

- by Your DisplayName here!

Every once in a while you run into a situation where you need to temporarily store data for a user in a web app. You typically have two options here – either store server-side or put the data into a cookie (if size permits). When you need web farm compatibility in addition – things become a little bit more complicated because the data needs to be available on all nodes. In my case I went for a cookie – but I had some requirements Cookie must be protected from eavesdropping (sent only over SSL) and client script Cookie must be encrypted and signed to be protected from tampering with Cookie might become bigger than 4KB – some sort of overflow mechanism would be nice I really didn’t want to implement another cookie protection mechanism – this feels wrong and btw can go wrong as well. WIF to the rescue. The session management feature already implements the above requirements but is built around de/serializing IClaimsPrincipals into cookies and back. But if you go one level deeper you will find the CookieHandler and CookieTransform classes which contain all the needed functionality. public class ProtectedCookie { private List<CookieTransform> _transforms; private ChunkedCookieHandler _handler = new ChunkedCookieHandler(); // DPAPI protection (single server) public ProtectedCookie() { _transforms = new List<CookieTransform> { new DeflateCookieTransform(), new ProtectedDataCookieTransform() }; } // RSA protection (load balanced) public ProtectedCookie(X509Certificate2 protectionCertificate) { _transforms = new List<CookieTransform> { new DeflateCookieTransform(), new RsaSignatureCookieTransform(protectionCertificate), new RsaEncryptionCookieTransform(protectionCertificate) }; } // custom transform pipeline public ProtectedCookie(List<CookieTransform> transforms) { _transforms = transforms; } public void Write(string name, string value, DateTime expirationTime) { byte[] encodedBytes = EncodeCookieValue(value); _handler.Write(encodedBytes, name, expirationTime); } public void Write(string name, string value, DateTime expirationTime, string domain, string path) { byte[] encodedBytes = EncodeCookieValue(value); _handler.Write(encodedBytes, name, path, domain, expirationTime, true, true, HttpContext.Current); } public string Read(string name) { var bytes = _handler.Read(name); if (bytes == null || bytes.Length == 0) { return null; } return DecodeCookieValue(bytes); } public void Delete(string name) { _handler.Delete(name); } protected virtual byte[] EncodeCookieValue(string value) { var bytes = Encoding.UTF8.GetBytes(value); byte[] buffer = bytes; foreach (var transform in _transforms) { buffer = transform.Encode(buffer); } return buffer; } protected virtual string DecodeCookieValue(byte[] bytes) { var buffer = bytes; for (int i = _transforms.Count; i > 0; i—) { buffer = _transforms[i - 1].Decode(buffer); } return Encoding.UTF8.GetString(buffer); } } HTH

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Keypress detection wont work after seemingly unrelated code change

- by LukeZaz

I'm trying to have the Enter key cause a new 'map' to generate for my game, but for whatever reason after implementing full-screen in it the input check won't work anymore. I tried removing the new code and only pressing one key at a time, but it still won't work. Here's the check code and the method it uses, along with the newMap method: public class Game1 : Microsoft.Xna.Framework.Game { // ... protected override void Update(GameTime gameTime) { // ... // Check if Enter was pressed - if so, generate a new map if (CheckInput(Keys.Enter, 1)) { blocks = newMap(map, blocks, console); } // ... } // Method: Checks if a key is/was pressed public bool CheckInput(Keys key, int checkType) { // Get current keyboard state KeyboardState newState = Keyboard.GetState(); bool retType = false; // Return type if (checkType == 0) { // Check Type: Is key currently down? if (newState.IsKeyDown(key)) { retType = true; } else { retType = false; } } else if (checkType == 1) { // Check Type: Was the key pressed? if (newState.IsKeyDown(key)) { if (!oldState.IsKeyDown(key)) { // Key was just pressed retType = true; } else { // Key was already pressed, return false retType = false; } } } // Save keyboard state oldState = newState; // Return result if (retType == true) { return true; } else { return false; } } // Method: Generate a new map public List<Block> newMap(Map map, List<Block> blockList, Console console) { // Create new map block coordinates List<Vector2> positions = new List<Vector2>(); positions = map.generateMap(console); // Clear list and reallocate memory previously used up by it blockList.Clear(); blockList.TrimExcess(); // Add new blocks to the list using positions created by generateMap() foreach (Vector2 pos in positions) { blockList.Add(new Block() { Position = pos, Texture = dirtTex }); } // Return modified list return blockList; } // ... } and the generateMap code: // Generate a list of Vector2 positions for blocks public List<Vector2> generateMap(Console console, int method = 0) { ScreenTileWidth = gDevice.Viewport.Width / 16; ScreenTileHeight = gDevice.Viewport.Height / 16; maxHeight = gDevice.Viewport.Height; List<Vector2> blockLocations = new List<Vector2>(); if (useScreenSize == true) { Width = ScreenTileWidth; Height = ScreenTileHeight; } else { maxHeight = Height; } int startHeight = -500; // For debugging purposes, the startHeight is set to an // hopefully-unreachable value - if it returns this, something is wrong // Methods of land generation /// <summary> /// Third version land generation /// Generates a base land height as the second version does /// but also generates a 'max change' value which determines how much /// the land can raise or lower by which it now does by a random amount /// during generation /// </summary> if (method == 0) { // Get the land height startHeight = rnd.Next(1, maxHeight); int maxChange = rnd.Next(1, 5); // Amount ground will raise/lower by int curHeight = startHeight; for (int w = 0; w < Width; w++) { // Run a chance to lower/raise ground level int changeBy = rnd.Next(1, maxChange); int doChange = rnd.Next(0, 3); if (doChange == 1 && !(curHeight <= (1 + maxChange))) { curHeight = curHeight - changeBy; } else if (doChange == 2 && !(curHeight >= (29 - maxChange))) { curHeight = curHeight + changeBy; } for (int h = curHeight; h < Height; h++) { // Location variables float x = w * 16; float y = h * 16; blockLocations.Add(new Vector2(x, y)); } } console.newMsg("[INFO] Cur, height change maximum: " + maxChange.ToString()); } /// <summary> /// Second version land generator /// Generates a solid mass of land starting at a random height /// derived from either screen height or provided height value /// </summary> else if (method == 1) { // Get the land height startHeight = rnd.Next(0, 30); for (int w = 0; w < Width; w++) { for (int h = startHeight; h < ScreenTileHeight; h++) { // Location variables float x = w * 16; float y = h * 16; // Add a tile at set location blockLocations.Add(new Vector2(x, y)); } } } /// <summary> /// First version land generator /// Generates land completely randomly either across screen or /// in a box set by Width and Height values /// </summary> else { // For each tile in the map... for (int w = 0; w < Width; w++) { for (int h = 0; h < Height; h++) { // Location variables float x = w * 16; float y = h * 16; // ...decide whether or not to place a tile... if (rnd.Next(0, 2) == 1) { // ...and if so, add a tile at that location. blockLocations.Add(new Vector2(x, y)); } } } } console.newMsg("[INFO] Cur, base height: " + startHeight.ToString()); return blockLocations; } I never touched any of the above code for this when it broke - changing keys won't seem to fix it. Despite this, I have camera movement set inside another Game1 method that uses WASD and works perfectly. All I did was add a few lines of code here: private int BackBufferWidth = 1280; // Added these variables private int BackBufferHeight = 800; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = BackBufferWidth; // and this graphics.PreferredBackBufferHeight = BackBufferHeight; // this Content.RootDirectory = "Content"; this.graphics.IsFullScreen = true; // and this } When I try adding a console line to be printed in the event the key is pressed, it seems that the If is never even triggered despite the correct key being pressed.

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Struct Method for Loops Problem

- by Annalyne

I have tried numerous times how to make a do-while loop using the float constructor for my code but it seems it does not work properly as I wanted. For summary, I am making a TBRPG in C++ and I encountered few problems. But before that, let me post my code. #include <iostream> #include <string> #include <ctime> #include <cstdlib> using namespace std; int char_level = 1; //the starting level of the character. string town; //town string town_name; //the name of the town the character is in. string charname; //holds the character's name upon the start of the game int gems = 0; //holds the value of the games the character has. const int MAX_ITEMS = 15; //max items the character can carry string inventory [MAX_ITEMS]; //the inventory of the character in game int itemnum = 0; //number of items that the character has. bool GameOver = false; //boolean intended for the game over scr. string monsterTroop [] = {"Slime", "Zombie", "Imp", "Sahaguin, Hounds, Vampire"}; //monster name float monsterTroopHealth [] = {5.0f, 10.0f, 15.0f, 20.0f, 25.0f}; // the health of the monsters int monLifeBox; //life carrier of the game's enemy troops int enemNumber; //enemy number //inventory[itemnum++] = "Sword"; class RPG_Game_Enemy { public: void enemyAppear () { srand(time(0)); enemNumber = 1+(rand()%3); if (enemNumber == 1) cout << monsterTroop[1]; //monster troop 1 else if (enemNumber == 2) cout << monsterTroop[2]; //monster troop 2 else if (enemNumber == 3) cout << monsterTroop[3]; //monster troop 3 else if (enemNumber == 4) cout << monsterTroop[4]; //monster troop 4 } void enemDefeat () { cout << "The foe has been defeated. You are victorious." << endl; } void enemyDies() { //if the enemy dies: //collapse declaration cout << "The foe vanished and you are victorious!" << endl; } }; class RPG_Scene_Battle { public: RPG_Scene_Battle(float ini_health) : health (ini_health){}; float getHealth() { return health; } void setHealth(float rpg_val){ health = rpg_val;}; private: float health; }; //---------------------------------------------------------------// // Conduct Damage for the Scene Battle's Damage //---------------------------------------------------------------// float conductDamage(RPG_Scene_Battle rpg_tr, float damage) { rpg_tr.setHealth(rpg_tr.getHealth() - damage); return rpg_tr.getHealth(); }; // ------------------------------------------------------------- // void RPG_Scene_DisplayItem () { cout << "Items: \n"; for (int i=0; i < itemnum; ++i) cout << inventory[i] <<endl; }; In this code I have so far, the problem I have is the battle scene. For example, the player battles a Ghost with 10 HP, when I use a do while loop to subtract the HP of the character and the enemy, it only deducts once in the do while. Some people said I should use a struct, but I have no idea how to make it. Is there a way someone can display a code how to implement it on my game? Edit: I made the do-while by far like this: do RPG_Scene_Battle (player, 20.0f); RPG_Scene_Battle (enemy, 10.0f); cout << "Battle starts!" <<endl; cout << "You used a blade skill and deducted 2 hit points to the enemy!" conductDamage (enemy, 2.0f); while (enemy!=0) also, I made something like this: #include <iostream> using namespace std; int gems = 0; class Entity { public: Entity(float startingHealth) : health(startingHealth){}; // initialize health float getHealth(){return health;} void setHealth(float value){ health = value;}; private: float health; }; float subtractHealthFrom(Entity& ent, float damage) { ent.setHealth(ent.getHealth() - damage); return ent.getHealth(); }; int main () { Entity character(10.0f); Entity enemy(10.0f); cout << "Hero Life: "; cout << subtractHealthFrom(character, 2.0f) <<endl; cout << "Monster Life: "; cout << subtractHealthFrom(enemy, 2.0f) <<endl; cout << "Hero Life: "; cout << subtractHealthFrom(character, 2.0f) <<endl; cout << "Monster Life: "; cout << subtractHealthFrom(enemy, 2.0f) <<endl; }; Struct method, they say, should solve this problem. How can I continously deduct hp from the enemy? Whenever I deduct something, it would return to its original value -_-

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Clouds Everywhere But not a Drop of Rain – Part 3

- by sxkumar

I was sharing with you how a broad-based transformation such as cloud will increase agility and efficiency of an organization if process re-engineering is part of the plan. I have also stressed on the key enterprise requirements such as “broad and deep solutions, “running your mission critical applications” and “automated and integrated set of capabilities”. Let me walk you through some key cloud attributes such as “elasticity” and “self-service” and what they mean for an enterprise class cloud. I will also talk about how we at Oracle have taken a very enterprise centric view to developing cloud solutions and how our products have been specifically engineered to address enterprise cloud needs. Cloud Elasticity and Enterprise Applications Requirements Easy and quick scalability for a short-period of time is the signature of cloud based solutions. It is this elasticity that allows you to dynamically redistribute your resources according to business priorities, helps increase your overall resource utilization, and reduces operational costs by allowing you to get the most out of your existing investment. Most public clouds are offering a instant provisioning mechanism of compute power (CPU, RAM, Disk), customer pay for the instance-hours(and bandwidth) they use, adding computing resources at peak times and removing them when they are no longer needed. This type of “just-in-time” serving of compute resources is well known for mid-tiers “state less” servers such as web application servers and web servers that just need another machine to start and run on it but what does it really mean for an enterprise application and its underlying data? Most enterprise applications are not as quite as “state less” and justifiably so. As such, how do you take advantage of cloud elasticity and make it relevant for your enterprise apps? This is where Cloud meets Grid Computing. At Oracle, we have invested enormous amount of time, energy and resources in creating enterprise grid solutions. All our technology products offer built-in elasticity via clustering and dynamic scaling. With products like Real Application Clusters (RAC), Automatic Storage Management, WebLogic Clustering, and Coherence In-Memory Grid, we allow all your enterprise applications to benefit from Cloud elasticity –both vertically and horizontally - without requiring any application changes. A number of technology vendors take a rather simplistic route of starting up additional or removing unneeded VM as the "Cloud Scale-Out" solution. While this may work for stateless mid-tier servers where load balancers can handle the addition and remove of instances transparently but following a similar approach for the database tier - often called as "database sharding" - requires significant application modification and typically does not work with off the shelf packaged applications. Technologies like Oracle Database Real Application Clusters, Automatic Storage Management, etc. on the other hand bring the benefits of incremental scalability and on-demand elasticity to ANY application by providing a simplified abstraction layers where the application does not need deal with data spread over multiple database instances. Rather they just talk to a single database and the database software takes care of aggregating resources across multiple hardware components. It is the technologies like these that truly make a cloud solution relevant for enterprises. For customers who are looking for a next generation hardware consolidation platform, our engineered systems (e.g. Exadata, Exalogic) not only provide incredible amount of performance and capacity, they also reduce the data center complexity and simplify operations. Assemble, Deploy and Manage Enterprise Applications for Cloud Products like Oracle Virtual assembly builder (OVAB) resolve the complex problem of bringing the cloud speed to complex multi-tier applications. With assemblies, you can not only provision all components of a multi-tier application and wire them together by push of a button, other aspects of application lifecycle, such as real-time application testing, scale-up/scale-down, performance and availability monitoring, etc., are also automated using Oracle Enterprise Manager. An essential criteria for an enterprise cloud to succeed is the ability to ensure business service levels especially when business users have either full visibility on the usage cost with a “show back” or a “charge back”. With Oracle Enterprise Manager 12c, we have created the most comprehensive cloud management solution in the industry that is capable of managing business service levels “applications-to-disk” in a enterprise private cloud – all from a single console. It is the only cloud management platform in the industry that allows you to deliver infrastructure, platform and application cloud services out of the box. Moreover, it offers integrated and complete lifecycle management of the cloud - including planning and set up, service delivery, operations management, metering and chargeback, etc . Sounds unbelievable? Well, just watch this space for more details on how Oracle Enterprise Manager 12c is the nerve center of Oracle Cloud! Our cloud solution portfolio is also the broadest and most deep in the industry - covering public, private, hybrid, Infrastructure, platform and applications clouds. It is no coincidence therefore that the Oracle Cloud today offers the most comprehensive set of public cloud services in the industry. And to a large part, this has been made possible thanks to our years on investment in creating cloud enabling technologies. Summary But the intent of this blog post isn't to dwell on how great our solutions are (these are just some examples to illustrate how we at Oracle have approached this problem space). Rather it is to help you ask the right questions before you embark on your cloud journey. So to summarize, here are the key takeaways. It is critical that you are clear on why you are building the cloud. Successful organizations keep business benefits as the first and foremost cloud objective. On the other hand, those who approach this purely as a technology project are more likely to fail. Think about where you want to be in 3-5 years before you get started. Your long terms objectives should determine what your first step ought to be. As obvious as it may seem, more people than not make the first move without knowing where they are headed. Don’t make the mistake of equating cloud to virtualization and Infrastructure-as-a-Service (IaaS). Spinning a VM on-demand will give some short term relief to your IT staff but is unlikely to solve your larger business problems. As such, even if IaaS is your first step towards a more comprehensive cloud, plan the roadmap around those higher level services before you begin. And ask your vendors on how they are going to be your partners in this journey. Capabilities like self-service access and chargeback/showback are absolutely critical if you really expect your cloud to be transformational. Your business won't see the full benefits of the cloud until it empowers them with same kind of control and transparency that they are used to while using a public cloud service. Evaluate the benefits of integration, as opposed to blindly following the best-of-breed strategy. Integration is a huge challenge and more so in a cloud environment. There are enormous costs associated with stitching a solution out of disparate components and even more in maintaining it. Hope you found these ideas helpful. Looking forward to hearing your thoughts and experiences.

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Portable class libraries and fetching JSON

- by Jeff

After much delay, we finally have the Windows Phone 8 SDK to go along with the Windows 8 Store SDK, or whatever ridiculous name they’re giving it these days. (Seriously… that no one could come up with a suitable replacement for “metro” is disappointing in an otherwise exciting set of product launches.) One of the neat-o things is the potential for code reuse, particularly across Windows 8 and Windows Phone 8 apps. This is accomplished in part with portable class libraries, which allow you to share code between different types of projects. With some other techniques and quasi-hacks, you can share some amount of code, and I saw it mentioned in one of the Build videos that they’re seeing as much as 70% code reuse. Not bad. However, I’ve already hit a super annoying snag. It appears that the HttpClient class, with its idiot-proof async goodness, is not included in the Windows Phone 8 class libraries. Shock, gasp, horror, disappointment, etc. The delay in releasing it already caused dismay among developers, and I’m sure this won’t help. So I started refactoring some code I already had for a Windows 8 Store app (ugh) to accommodate the use of HttpWebRequest instead. I haven’t tried it in a Windows Phone 8 project beyond compiling, but it appears to work. I used this StackOverflow answer as a starting point since it’s been a long time since I used HttpWebRequest, and keep in mind that it has no exception handling. It needs refinement. The goal here is to new up the client, and call a method that returns some deserialized JSON objects from the Intertubes. Adding facilities for headers or cookies is probably a good next step. You need to use NuGet for a Json.NET reference. So here’s the start: using System.Net; using System.Threading.Tasks; using Newtonsoft.Json; using System.IO; namespace MahProject { public class ServiceClient<T> where T : class { public ServiceClient(string url) { _url = url; } private readonly string _url; public async Task<T> GetResult() { var response = await MakeAsyncRequest(_url); var result = JsonConvert.DeserializeObject<T>(response); return result; } public static Task<string> MakeAsyncRequest(string url) { var request = (HttpWebRequest)WebRequest.Create(url); request.ContentType = "application/json"; Task<WebResponse> task = Task.Factory.FromAsync( request.BeginGetResponse, asyncResult => request.EndGetResponse(asyncResult), null); return task.ContinueWith(t => ReadStreamFromResponse(t.Result)); } private static string ReadStreamFromResponse(WebResponse response) { using (var responseStream = response.GetResponseStream()) using (var reader = new StreamReader(responseStream)) { var content = reader.ReadToEnd(); return content; } } } } Calling it in some kind of repository class may look like this, if you wanted to return an array of Park objects (Park model class omitted because it doesn’t matter): public class ParkRepo { public async Task<Park[]> GetAllParks() { var client = new ServiceClient<Park[]>(http://superfoo/endpoint); return await client.GetResult(); } } And then from inside your WP8 or W8S app (see what I did there?), when you load state or do some kind of UI event handler (making sure the method uses the async keyword): var parkRepo = new ParkRepo(); var results = await parkRepo.GetAllParks(); // bind results to some UI or observable collection or something Hopefully this saves you a little time.

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SharePoint logging to a list

- by Norgean

I recently worked in an environment with several servers. Locating the correct SharePoint log file for error messages, or development trace calls, is cumbersome. And once the solution hit the cloud, it got even worse, as we had no access to the log files at all. Obviously we are not the only ones with this problem, and the current trend seems to be to log to a list. This had become an off-hour project, so rather than do the sensible thing and find a ready-made solution, I decided to do it the hard way. So! Fire up Visual Studio, create yet another empty SharePoint solution, and start to think of some requirements. Easy on/offI want to be able to turn list-logging on and off.Easy loggingFor me, this means being able to use string.Format.Easy filteringLet's have the possibility to add some filtering columns; category and severity, where severity can be "verbose", "warning" or "error". Easy on/off Well, that's easy. Create a new web feature. Add an event receiver, and create the list on activation of the feature. Tear the list down on de-activation. I chose not to create a new content type; I did not feel that it would give me anything extra. I based the list on the generic list - I think a better choice would have been the announcement type. Approximately: public void CreateLog(SPWeb web) { var list = web.Lists.TryGetList(LogListName); if (list == null) { var listGuid = web.Lists.Add(LogListName, "Logging for the masses", SPListTemplateType.GenericList); list = web.Lists[listGuid]; list.Title = LogListTitle; list.Update(); list.Fields.Add(Category, SPFieldType.Text, false); var stringColl = new StringCollection(); stringColl.AddRange(new[]{Error, Information, Verbose}); list.Fields.Add(Severity, SPFieldType.Choice, true, false, stringColl); ModifyDefaultView(list); } }Should be self explanatory, but: only create the list if it does not already exist (d'oh). Best practice: create it with a Url-friendly name, and, if necessary, give it a better title. ...because otherwise you'll have to look for a list with a name like "Simple_x0020_Log". I've added a couple of fields; a field for category, and a 'severity'. Both to make it easier to find relevant log messages. Notice that I don't have to call list.Update() after adding the fields - this would cause a nasty error (something along the lines of "List locked by another user"). The function for deleting the log is exactly as onerous as you'd expect: public void DeleteLog(SPWeb web) { var list = web.Lists.TryGetList(LogListTitle); if (list != null) { list.Delete(); } } So! "All" that remains is to log. Also known as adding items to a list. Lots of different methods with different signatures end up calling the same function. For example, LogVerbose(web, message) calls LogVerbose(web, null, message) which again calls another method which calls: private static void Log(SPWeb web, string category, string severity, string textformat, params object[] texts) { if (web != null) { var list = web.Lists.TryGetList(LogListTitle); if (list != null) { var item = list.AddItem(); // NOTE! NOT list.Items.Add… just don't, mkay? var text = string.Format(textformat, texts); if (text.Length > 255) // because the title field only holds so many chars. Sigh. text = text.Substring(0, 254); item[SPBuiltInFieldId.Title] = text; item[Degree] = severity; item[Category] = category; item.Update(); } } // omitted: Also log to SharePoint log. } By adding a params parameter I can call it as if I was doing a Console.WriteLine: LogVerbose(web, "demo", "{0} {1}{2}", "hello", "world", '!'); Ok, that was a silly example, a better one might be: LogError(web, LogCategory, "Exception caught when updating {0}. exception: {1}", listItem.Title, ex); For performance reasons I use list.AddItem rather than list.Items.Add. For completeness' sake, let us include the "ModifyDefaultView" function that I deliberately skipped earlier. private void ModifyDefaultView(SPList list) { // Add fields to default view var defaultView = list.DefaultView; var exists = defaultView.ViewFields.Cast<string>().Any(field => String.CompareOrdinal(field, Severity) == 0); if (!exists) { var field = list.Fields.GetFieldByInternalName(Severity); if (field != null) defaultView.ViewFields.Add(field); field = list.Fields.GetFieldByInternalName(Category); if (field != null) defaultView.ViewFields.Add(field); defaultView.Update(); var sortDoc = new XmlDocument(); sortDoc.LoadXml(string.Format("<Query>{0}</Query>", defaultView.Query)); var orderBy = (XmlElement) sortDoc.SelectSingleNode("//OrderBy"); if (orderBy != null && sortDoc.DocumentElement != null) sortDoc.DocumentElement.RemoveChild(orderBy); orderBy = sortDoc.CreateElement("OrderBy"); sortDoc.DocumentElement.AppendChild(orderBy); field = list.Fields[SPBuiltInFieldId.Modified]; var fieldRef = sortDoc.CreateElement("FieldRef"); fieldRef.SetAttribute("Name", field.InternalName); fieldRef.SetAttribute("Ascending", "FALSE"); orderBy.AppendChild(fieldRef); fieldRef = sortDoc.CreateElement("FieldRef"); field = list.Fields[SPBuiltInFieldId.ID]; fieldRef.SetAttribute("Name", field.InternalName); fieldRef.SetAttribute("Ascending", "FALSE"); orderBy.AppendChild(fieldRef); defaultView.Query = sortDoc.DocumentElement.InnerXml; //defaultView.Query = "<OrderBy><FieldRef Name='Modified' Ascending='FALSE' /><FieldRef Name='ID' Ascending='FALSE' /></OrderBy>"; defaultView.Update(); } } First two lines are easy - see if the default view includes the "Severity" column. If it does - quit; our job here is done.Adding "severity" and "Category" to the view is not exactly rocket science. But then? Then we build the sort order query. Through XML. The lines are numerous, but boring. All to achieve the CAML query which is commented out. The major benefit of using the dom to build XML, is that you may get compile time errors for spelling mistakes. I say 'may', because although the compiler will not let you forget to close a tag, it will cheerfully let you spell "Name" as "Naem". Whichever you prefer, at the end of the day the view will sort by modified date and ID, both descending. I added the ID as there may be several items with the same time stamp. So! Simple logging to a list, with sensible a view, and with normal functionality for creating your own filterings. I should probably have added some more views in code, ready filtered for "only errors", "errors and warnings" etc. And it would be nice to block verbose logging completely, but I'm not happy with the alternatives. (yetanotherfeature or an admin page seem like overkill - perhaps just removing it as one of the choices, and not log if it isn't there?) Before you comment - yes, try-catches have been removed for clarity. There is nothing worse than having a logging function that breaks your site!

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What's new in EJB 3.2 ? - Java EE 7 chugging along!

- by arungupta

EJB 3.1 added a whole ton of features for simplicity and ease-of-use such as @Singleton, @Asynchronous, @Schedule, Portable JNDI name, EJBContainer.createEJBContainer, EJB 3.1 Lite, and many others. As part of Java EE 7, EJB 3.2 (JSR 345) is making progress and this blog will provide highlights from the work done so far. This release has been particularly kept small but include several minor improvements and tweaks for usability. More features in EJB.Lite Asynchronous session bean Non-persistent EJB Timer service This also means these features can be used in embeddable EJB container and there by improving testability of your application. Pruning - The following features were made Proposed Optional in Java EE 6 and are now made optional. EJB 2.1 and earlier Entity Bean Component Contract for CMP and BMP Client View of an EJB 2.1 and earlier Entity Bean EJB QL: Query Language for CMP Query Methods JAX-RPC-based Web Service Endpoints and Client View The optional features are moved to a separate document and as a result EJB specification is now split into Core and Optional documents. This allows the specification to be more readable and better organized. Updates and Improvements Transactional lifecycle callbacks in Stateful Session Beans, only for CMT. In EJB 3.1, the transaction context for lifecyle callback methods (@PostConstruct, @PreDestroy, @PostActivate, @PrePassivate) are defined as shown. @PostConstruct @PreDestroy @PrePassivate @PostActivate Stateless Unspecified Unspecified N/A N/A Stateful Unspecified Unspecified Unspecified Unspecified Singleton Bean's transaction management type Bean's transaction management type N/A N/A In EJB 3.2, stateful session bean lifecycle callback methods can opt-in to be transactional. These methods are then executed in a transaction context as shown. @PostConstruct @PreDestroy @PrePassivate @PostActivate Stateless Unspecified Unspecified N/A N/A Stateful Bean's transaction management type Bean's transaction management type Bean's transaction management type Bean's transaction management type Singleton Bean's transaction management type Bean's transaction management type N/A N/A For example, the following stateful session bean require a new transaction to be started for @PostConstruct and @PreDestroy lifecycle callback methods. @Statefulpublic class HelloBean { @PersistenceContext(type=PersistenceContextType.EXTENDED) private EntityManager em; @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW) @PostConstruct public void init() { myEntity = em.find(...); } @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW) @PostConstruct public void destroy() { em.flush(); }} Notice, by default the lifecycle callback methods are not transactional for backwards compatibility. They need to be explicitly opt-in to be made transactional. Opt-out of passivation for stateful session bean - If your stateful session bean needs to stick around or it has non-serializable field then the bean can be opt-out of passivation as shown. @Stateful(passivationCapable=false)public class HelloBean { private NonSerializableType ref = ... . . .} Simplified the rules to define all local/remote views of the bean. For example, if the bean is defined as: @Statelesspublic class Bean implements Foo, Bar { . . .} where Foo and Bar have no annotations of their own, then Foo and Bar are exposed as local views of the bean. The bean may be explicitly marked @Local as @Local@Statelesspublic class Bean implements Foo, Bar { . . .} then this is the same behavior as explained above, i.e. Foo and Bar are local views. If the bean is marked @Remote as: @Remote@Statelesspublic class Bean implements Foo, Bar { . . .} then Foo and Bar are remote views. If an interface is marked @Local or @Remote then each interface need to be explicitly marked explicitly to be exposed as a view. For example: @Remotepublic interface Foo { . . . }@Statelesspublic class Bean implements Foo, Bar { . . .} only exposes one remote interface Foo. Section 4.9.7 from the specification provide more details about this feature. TimerService.getAllTimers is a newly added convenience API that returns all timers in the same bean. This is only for displaying the list of timers as the timer can only be canceled by its owner. Removed restriction to obtain the current class loader, and allow to use java.io package. This is handy if you want to do file access within your beans. JMS 2.0 alignment - A standard list of activation-config properties is now defined destinationLookup connectionFactoryLookup clientId subscriptionName shareSubscriptions Tons of other clarifications through out the spec. Appendix A provide a comprehensive list of changes since EJB 3.1. ThreadContext in Singleton is guaranteed to be thread-safe. Embeddable container implement Autocloseable. A complete replay of Enterprise JavaBeans Today and Tomorrow from JavaOne 2012 can be seen here (click on CON4654_mp4_4654_001 in Media). The specification is still evolving so the actual property or method names or their actual behavior may be different from the currently proposed ones. Are there any improvements that you'd like to see in EJB 3.2 ? The EJB 3.2 Expert Group would love to hear your feedback. An Early Draft of the specification is available. The latest version of the specification can always be downloaded from here. Java EE 7 Specification Status EJB Specification Project JIRA of EJB Specification JSR Expert Group Discussion Archive These features will start showing up in GlassFish 4 Promoted Builds soon.

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C# 2D Camera Max Zoom

- by Craig

I have a simple ship sprite moving around the screen along with a 2D Camera. I have zooming in and out working, however when I zoom out it goes past the world bounds and has the cornflower blue background showing. How do I sort it that I can only zoom out as far as showing the entire world (which is a picture of OZ) and thats it? I dont want any of the cornflower blue showing. Cheers! namespace GamesCoursework_1 { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; SpriteBatch spriteBatch; // player variables Texture2D Ship; Vector2 Ship_Position; float Ship_Rotation = 0.0f; Vector2 Ship_Origin; Vector2 Ship_Velocity; const float tangentialVelocity = 4f; float friction = 0.05f; static Point CameraViewport = new Point(800, 800); Camera2d cam = new Camera2d((int)CameraViewport.X, (int)CameraViewport.Y); //Size of world static Point worldSize = new Point(1600, 1600); // Screen variables static Point worldCenter = new Point(worldSize.X / 2, worldSize.Y / 2); Rectangle playerBounds = new Rectangle(CameraViewport.X / 2, CameraViewport.Y / 2, worldSize.X - CameraViewport.X, worldSize.Y - CameraViewport.Y); Rectangle worldBounds = new Rectangle(0, 0, worldSize.X, worldSize.Y); Texture2D background; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = CameraViewport.X; graphics.PreferredBackBufferHeight = CameraViewport.Y; Content.RootDirectory = "Content"; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); // TODO: use this.Content to load your game content here Ship = Content.Load<Texture2D>("Ship"); Ship_Origin.X = Ship.Width / 2; Ship_Origin.Y = Ship.Height / 2; background = Content.Load<Texture2D>("aus"); Ship_Position = new Vector2(worldCenter.X, worldCenter.Y); cam.Pos = Ship_Position; cam.Zoom = 1f; } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { // TODO: Unload any non ContentManager content here } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Update(GameTime gameTime) { // Allows the game to exit if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) this.Exit(); // TODO: Add your update logic here Ship_Position = Ship_Velocity + Ship_Position; keyPressed(); base.Update(gameTime); } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); // TODO: Add your drawing code here spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend, null, null, null,null, cam.get_transformation(GraphicsDevice)); spriteBatch.Draw(background, Vector2.Zero, Color.White); spriteBatch.Draw(Ship, Ship_Position, Ship.Bounds, Color.White, Ship_Rotation, Ship_Origin, 1.0f, SpriteEffects.None, 0f); spriteBatch.End(); base.Draw(gameTime); } private void Ship_Move(Vector2 move) { Ship_Position += move; } private void keyPressed() { KeyboardState keyState; // Move right keyState = Keyboard.GetState(); if (keyState.IsKeyDown(Keys.Right)) { Ship_Rotation = Ship_Rotation + 0.1f; } if (keyState.IsKeyDown(Keys.Left)) { Ship_Rotation = Ship_Rotation - 0.1f; } if (keyState.IsKeyDown(Keys.Up)) { Ship_Velocity.X = (float)Math.Cos(Ship_Rotation) * tangentialVelocity; Ship_Velocity.Y = (float)Math.Sin(Ship_Rotation) * tangentialVelocity; if ((int)Ship_Position.Y < playerBounds.Bottom && (int)Ship_Position.Y > playerBounds.Top) cam._pos.Y = Ship_Position.Y; if ((int)Ship_Position.X > playerBounds.Left && (int)Ship_Position.X < playerBounds.Right) cam._pos.X = Ship_Position.X; Ship_Position += new Vector2(tangentialVelocity, 0); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(tangentialVelocity * 2, 0.0f); Ship_Position += new Vector2(-tangentialVelocity, 0.0f); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(-tangentialVelocity * 2, 0.0f); Ship_Position += new Vector2(0.0f, -tangentialVelocity); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(0.0f, -tangentialVelocity * 2); Ship_Position += new Vector2(0.0f, tangentialVelocity); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(0.0f, 2 * tangentialVelocity); } else if(Ship_Velocity != Vector2.Zero) { float i = Ship_Velocity.X; float j = Ship_Velocity.Y; Ship_Velocity.X = i -= friction * i; Ship_Velocity.Y = j -= friction * j; if ((int)Ship_Position.Y < playerBounds.Bottom && (int)Ship_Position.Y > playerBounds.Top) cam._pos.Y = Ship_Position.Y; if ((int)Ship_Position.X > playerBounds.Left && (int)Ship_Position.X < playerBounds.Right) cam._pos.X = Ship_Position.X; Ship_Position += new Vector2(tangentialVelocity, 0); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(tangentialVelocity * 2, 0.0f); Ship_Position += new Vector2(-tangentialVelocity, 0.0f); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(-tangentialVelocity * 2, 0.0f); Ship_Position += new Vector2(0.0f, -tangentialVelocity); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(0.0f, -tangentialVelocity * 2); Ship_Position += new Vector2(0.0f, tangentialVelocity); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(0.0f, 2 * tangentialVelocity); } if (keyState.IsKeyDown(Keys.Q)) { if (cam.Zoom < 2f) cam.Zoom += 0.05f; } if (keyState.IsKeyDown(Keys.A)) { if (cam.Zoom > 0.3f) cam.Zoom -= 0.05f; } } } }

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Complex event system for DungeonKeeper like game

- by paul424

I am working on opensource GPL3 game. http://opendungeons.sourceforge.net/ , new coders would be welcome. Now there's design question regarding Event System: We want to improve the game logic, that is program a new event system. I will just repost what's settled up already on http://forum.freegamedev.net/viewtopic.php?f=45&t=3033. From the discussion came the idea of the Publisher / Subscriber pattern + "domains": My current idea is to use the subscirbers / publishers model. Its similar to Observable pattern, but instead one subscribes to Events types, not Object's Events. For each Event would like to have both static and dynamic type. Static that is its's type would be resolved by belonging to the proper inherited class from Event. That is from Event we would have EventTile, EventCreature, EvenMapLoader, EventGameMap etc. From that there are of course subtypes like EventCreature would be EventKobold, EventKnight, EventTentacle etc. The listeners would collect the event from publishers, and send them subcribers , each of them would be a global singleton. The Listeners type hierachy would exactly mirror the type hierarchy of Events. In each constructor of Event type, the created instance would notify the proper listeners. That is when calling EventKnight the proper ctor would notify the Listeners : EventListener, CreatureLisener and KnightListener. The default action for an listner would be to notify all subscribers, but there would be some exceptions , like EventAttack would notify AttackListener which would dispatch event by the dynamic part ( that is the Creature pointer or hash). Any comments ? #include <vector> class Subscriber; class SubscriberAttack; class Event{ private: int foo; int bar; protected: // static std::vector<Publisher*> publishersList; static std::vector<Subscriber*> subscribersList; static std::vector<Event*> eventQueue; public: Event(){ eventQueue.push_back(this); } static int subscribe(Subscriber* ss); static int unsubscribe(Subscriber* ss); //static int reg_publisher(Publisher* pp); //static int unreg_publisher(Publisher* pp); }; // class Publisher{ // }; class Subscriber{ public: int (*newEvent) (Event* ee); Subscriber( ){ Event::subscribe(this); } Subscriber( int (*fp) (Event* ee) ):newEvent(fp){ Subscriber(); } ~Subscriber(){ Event::unsubscribe(this); } }; class EventAttack: Event{ private: int foo; int bar; protected: // static std::vector<Publisher*> publishersList; static std::vector<SubscriberAttack*> subscribersList; static std::vector<EventAttack*> eventQueue; public: EventAttack(){ eventQueue.push_back(this); } static int subscribe(SubscriberAttack* ss); static int unsubscribe(SubscriberAttack* ss); //static int reg_publisher(Publisher* pp); //static int unreg_publisher(Publisher* pp); }; class AttackSubscriber :Subscriber{ public: int (*newEvent) (EventAttack* ee); AttackSubscriber( ){ EventAttack::subscribe(this); } AttackSubscriber( int (*fp) (EventAttack* ee) ):newEventAttack(fp){ AttackSubscriber(); } ~AttackSubscriber(){ EventAttack::unsubscribe(this); } }; From that point, others wanted the Subject-Observer pattern, that is one would subscribe to all event types produced by particular object. That way it came out to add the domain system : Huh, to meet the ability to listen to particular game's object events, I though of introducing entity domains . Domains are trees, which nodes are labeled by unique names for each level. ( like the www addresses ). Each Entity wanting to participate in our event system ( that is be able to publish / produce events ) should at least now its domain name. That would end up in Player1/Room/Treasury/#24 or Player1/Creature/Kobold/#3 producing events. The subscriber picks some part of a tree. For example by specifiing subtree with the root in one of the nodes like Player1/Room/* ,would subscribe us to all Players1's room's event, and Player1/Creature/Kobold/#3 would subscribe to Players' third kobold's event. Does such event system make sense to you ? I have many implementation details to ask as well, but first let's start some general discussion. Note1: Notice that in the case of a fight between two creatues fight , the creature being attacked would have to throw an event, becuase it is HE/SHE/IT who have its domain address. So that would be BeingAttackedEvent() etc. I will edit that post if some other reflections on this would come out. Note2: the existing class hierarchy might be used to get the domains addresses being build in constructor . In a ctor you would just add + ."className" to domain address. If you are in a class'es hierarchy leaf constructor one might use nextID , hash or any other charactteristic, just to make the addresses distinguishable . Note3:subscribing to all entity's Events would require knowledge of all possible events produced by this entity . This could be done in one function call, but information on E produced would have to be handled for every Entity. SmartNote4 : Finding proper subscribers in a tree would be easy. One would start in particular Leaf for example Player1/Creature/Kobold/#3 and go up one parent a time , notifiying each Subscriber in a Node ie. : Player1/Creature/Kobold/* , Player1/Creature/* , Player1/* etc, , up to a root that is /* .<<<< Note5: The Event system was needed to have some way of incorporating Angelscript code into application. So the Event dispatcher was to be a gate to A-script functions. But it came out to this one.

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Adding multiple data importers support to web applications

- by DigiMortal

I’m building web application for customer and there is requirement that users must be able to import data in different formats. Today we will support XLSX and ODF as import formats and some other formats are waiting. I wanted to be able to add new importers on the fly so I don’t have to deploy web application again when I add new importer or change some existing one. In this posting I will show you how to build generic importers support to your web application. Importer interface All importers we use must have something in common so we can easily detect them. To keep things simple I will use interface here. public interface IMyImporter { string[] SupportedFileExtensions { get; } ImportResult Import(Stream fileStream, string fileExtension); } Our interface has the following members: SupportedFileExtensions – string array of file extensions that importer supports. This property helps us find out what import formats are available and which importer to use with given format. Import – method that does the actual importing work. Besides file we give in as stream we also give file extension so importer can decide how to handle the file. It is enough to get started. When building real importers I am sure you will switch over to abstract base class. Importer class Here is sample importer that imports data from Excel and Word documents. Importer class with no implementation details looks like this: public class MyOpenXmlImporter : IMyImporter { public string[] SupportedFileExtensions { get { return new[] { "xlsx", "docx" }; } } public ImportResult Import(Stream fileStream, string extension) { // ... } } Finding supported import formats in web application Now we have importers created and it’s time to add them to web application. Usually we have one page or ASP.NET MVC controller where we need importers. To this page or controller we add the following method that uses reflection to find all classes that implement our IMyImporter interface. private static string[] GetImporterFileExtensions() { var types = from a in AppDomain.CurrentDomain.GetAssemblies() from t in a.GetTypes() where t.GetInterfaces().Contains(typeof(IMyImporter)) select t; var extensions = new Collection<string>(); foreach (var type in types) { var instance = (IMyImporter)type.InvokeMember(null, BindingFlags.CreateInstance, null, null, null); foreach (var extension in instance.SupportedFileExtensions) { if (extensions.Contains(extension)) continue; extensions.Add(extension); } } return extensions.ToArray(); } This code doesn’t look nice and is far from optimal but it works for us now. It is possible to improve performance of web application if we cache extensions and their corresponding types to some static dictionary. We have to fill it only once because our application is restarted when something changes in bin folder. Finding importer by extension When user uploads file we need to detect the extension of file and find the importer that supports given extension. We add another method to our page or controller that uses reflection to return us importer instance or null if extension is not supported. private static IMyImporter GetImporterForExtension(string extensionToFind) { var types = from a in AppDomain.CurrentDomain.GetAssemblies() from t in a.GetTypes() where t.GetInterfaces().Contains(typeof(IMyImporter)) select t; foreach (var type in types) { var instance = (IMyImporter)type.InvokeMember(null, BindingFlags.CreateInstance, null, null, null); if (instance.SupportedFileExtensions.Contains(extensionToFind)) { return instance; } } return null; } Here is example ASP.NET MVC controller action that accepts uploaded file, finds importer that can handle file and imports data. Again, this is sample code I kept minimal to better illustrate how things work. public ActionResult Import(MyImporterModel model) { var file = Request.Files[0]; var extension = Path.GetExtension(file.FileName).ToLower(); var importer = GetImporterForExtension(extension.Substring(1)); var result = importer.Import(file.InputStream, extension); if (result.Errors.Count > 0) { foreach (var error in result.Errors) ModelState.AddModelError("file", error); return Import(); } return RedirectToAction("Index"); } Conclusion That’s it. Using couple of ugly methods and one simple interface we were able to add importers support to our web application. Example code here is not perfect but it works. It is possible to cache mappings between file extensions and importer types to some static variable because changing of these mappings means that something is changed in bin folder of web application and web application is restarted in this case anyway.

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Reading XML Content

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Xml.Linq; using System.Diagnostics; using System.Threading; using System.Xml; using System.Reflection; namespace XMLReading { class Program { static void Main(string[] args) { string fileName = @"C:\temp\t.xml"; List<EmergencyContactXMLDTO> emergencyContacts = new XmlReader<EmergencyContactXMLDTO, EmergencyContactXMLDTOMapper>().Read(fileName); foreach (var item in emergencyContacts) { Console.WriteLine(item.FileNb); } } } public class XmlReader<TDTO, TMAPPER> where TDTO : BaseDTO, new() where TMAPPER : PCPWXMLDTOMapper, new() { public List<TDTO> Read(String fileName) { XmlTextReader reader = new XmlTextReader(fileName); List<TDTO> emergencyContacts = new List<TDTO>(); while (true) { TMAPPER mapper = new TMAPPER(); bool isFound = SeekElement(reader, mapper.GetMainXMLTagName()); if (!isFound) break; TDTO dto = new TDTO(); foreach (var propertyKey in mapper.GetPropertyXMLMap()) { String dtoPropertyName = propertyKey.Key; String xmlPropertyName = propertyKey.Value; SeekElement(reader, xmlPropertyName); SetValue(dto, dtoPropertyName, reader.ReadElementString()); } emergencyContacts.Add(dto); } return emergencyContacts; } private void SetValue(Object dto, String propertyName, String value) { PropertyInfo prop = dto.GetType().GetProperty(propertyName, BindingFlags.Public | BindingFlags.Instance); prop.SetValue(dto, value, null); } private bool SeekElement(XmlTextReader reader, String elementName) { while (reader.Read()) { XmlNodeType nodeType = reader.MoveToContent(); if (nodeType != XmlNodeType.Element) { continue; } if (reader.Name == elementName) { return true; } } return false; } } public class BaseDTO { } public class EmergencyContactXMLDTO : BaseDTO { public string FileNb { get; set; } public string ContactName { get; set; } public string ContactPhoneNumber { get; set; } public string Relationship { get; set; } public string DoctorName { get; set; } public string DoctorPhoneNumber { get; set; } public string HospitalName { get; set; } } public interface PCPWXMLDTOMapper { Dictionary<string, string> GetPropertyXMLMap(); String GetMainXMLTagName(); } public class EmergencyContactXMLDTOMapper : PCPWXMLDTOMapper { public Dictionary<string, string> GetPropertyXMLMap() { return new Dictionary<string, string> { { "FileNb", "XFileNb" }, { "ContactName", "XContactName"}, { "ContactPhoneNumber", "XContactPhoneNumber" }, { "Relationship", "XRelationship" }, { "DoctorName", "XDoctorName" }, { "DoctorPhoneNumber", "XDoctorPhoneNumber" }, { "HospitalName", "XHospitalName" }, }; } public String GetMainXMLTagName() { return "EmergencyContact"; } } } span.fullpost {display:none;}

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ASP.NET MVC - dropdown list post handling problem

- by ile

I've had troubles for a few days already with handling form that contains dropdown list. I tried all that I've learned so far but nothing helps. This is my code: using System; using System.Collections.Generic; using System.Linq; using System.Web; using CMS; using CMS.Model; using System.ComponentModel.DataAnnotations; namespace Portal.Models { public class ArticleDisplay { public ArticleDisplay() { } public int CategoryID { set; get; } public string CategoryTitle { set; get; } public int ArticleID { set; get; } public string ArticleTitle { set; get; } public DateTime ArticleDate; public string ArticleContent { set; get; } } public class HomePageViewModel { public HomePageViewModel(IEnumerable<ArticleDisplay> summaries, Article article) { this.ArticleSummaries = summaries; this.NewArticle = article; } public IEnumerable<ArticleDisplay> ArticleSummaries { get; private set; } public Article NewArticle { get; private set; } } public class ArticleRepository { private DB db = new DB(); // // Query Methods public IQueryable<ArticleDisplay> FindAllArticles() { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID orderby article.Date descending select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } public IQueryable<ArticleDisplay> FindTodayArticles() { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID where article.Date == DateTime.Today select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } public Article GetArticle(int id) { return db.Articles.SingleOrDefault(d => d.ArticleID == id); } public IQueryable<ArticleDisplay> DetailsArticle(int id) { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID where id == article.ArticleID select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } // // Insert/Delete Methods public void Add(Article article) { db.Articles.InsertOnSubmit(article); } public void Delete(Article article) { db.Articles.DeleteOnSubmit(article); } // // Persistence public void Save() { db.SubmitChanges(); } } } using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using Portal.Models; using CMS.Model; namespace Portal.Areas.CMS.Controllers { public class ArticleController : Controller { ArticleRepository articleRepository = new ArticleRepository(); ArticleCategoryRepository articleCategoryRepository = new ArticleCategoryRepository(); // // GET: /Article/ public ActionResult Index() { ViewData["categories"] = new SelectList ( articleCategoryRepository.FindAllCategories().ToList(), "CategoryId", "Title" ); Article article = new Article() { Date = DateTime.Now, CategoryID = 1 }; HomePageViewModel homeData = new HomePageViewModel(articleRepository.FindAllArticles().ToList(), article); return View(homeData); } // // GET: /Article/Details/5 public ActionResult Details(int id) { var article = articleRepository.DetailsArticle(id).Single(); if (article == null) return View("NotFound"); return View(article); } // // GET: /Article/Create //public ActionResult Create() //{ // ViewData["categories"] = new SelectList // ( // articleCategoryRepository.FindAllCategories().ToList(), "CategoryId", "Title" // ); // Article article = new Article() // { // Date = DateTime.Now, // CategoryID = 1 // }; // return View(article); //} // // POST: /Article/Create [ValidateInput(false)] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Create(Article article) { if (ModelState.IsValid) { try { // TODO: Add insert logic here articleRepository.Add(article); articleRepository.Save(); return RedirectToAction("Index"); } catch { return View(article); } } else { return View(article); } } // // GET: /Article/Edit/5 public ActionResult Edit(int id) { ViewData["categories"] = new SelectList ( articleCategoryRepository.FindAllCategories().ToList(), "CategoryId", "Title" ); var article = articleRepository.GetArticle(id); return View(article); } // // POST: /Article/Edit/5 [ValidateInput(false)] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(int id, FormCollection collection) { Article article = articleRepository.GetArticle(id); try { // TODO: Add update logic here UpdateModel(article, collection.ToValueProvider()); articleRepository.Save(); return RedirectToAction("Details", new { id = article.ArticleID }); } catch { return View(article); } } // // HTTP GET: /Article/Delete/1 public ActionResult Delete(int id) { Article article = articleRepository.GetArticle(id); if (article == null) return View("NotFound"); else return View(article); } // // HTTP POST: /Article/Delete/1 [AcceptVerbs(HttpVerbs.Post)] public ActionResult Delete(int id, string confirmButton) { Article article = articleRepository.GetArticle(id); if (article == null) return View("NotFound"); articleRepository.Delete(article); articleRepository.Save(); return View("Deleted"); } [ValidateInput(false)] public ActionResult UpdateSettings(int id, string value, string field) { // This highly-specific example is from the original coder's blog system, // but you can substitute your own code here. I assume you can pick out // which text field it is from the id. Article article = articleRepository.GetArticle(id); if (article == null) return Content("Error"); if (field == "Title") { article.Title = value; UpdateModel(article, new[] { "Title" }); articleRepository.Save(); } if (field == "Content") { article.Content = value; UpdateModel(article, new[] { "Content" }); articleRepository.Save(); } if (field == "Date") { article.Date = Convert.ToDateTime(value); UpdateModel(article, new[] { "Date" }); articleRepository.Save(); } return Content(value); } } } and view: <%@ Page Title="" Language="C#" MasterPageFile="~/Areas/CMS/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<Portal.Models.HomePageViewModel>" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> Index </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <div class="naslov_poglavlja_main">Articles Administration</div> <%= Html.ValidationSummary("Create was unsuccessful. Please correct the errors and try again.") %> <% using (Html.BeginForm("Create","Article")) {%> <div class="news_forma"> <label for="Title" class="news">Title:</label> <%= Html.TextBox("Title", "", new { @class = "news" })%> <%= Html.ValidationMessage("Title", "*") %> <label for="Content" class="news">Content:</label> <div class="textarea_okvir"> <%= Html.TextArea("Content", "", new { @class = "news" })%> <%= Html.ValidationMessage("Content", "*")%> </div> <label for="CategoryID" class="news">Category:</label> <%= Html.DropDownList("CategoryId", (IEnumerable<SelectListItem>)ViewData["categories"], new { @class = "news" })%> <p> <input type="submit" value="Publish" class="form_submit" /> </p> </div> <% } %> <div class="naslov_poglavlja_main"><%= Html.ActionLink("Write new article...", "Create") %></div> <div id="articles"> <% foreach (var item in Model.ArticleSummaries) { %> <div> <div class="naslov_vijesti" id="<%= item.ArticleID %>"><%= Html.Encode(item.ArticleTitle) %></div> <div class="okvir_vijesti"> <div class="sadrzaj_vijesti" id="<%= item.ArticleID %>"><%= item.ArticleContent %></div> <div class="datum_vijesti" id="<%= item.ArticleID %>"><%= Html.Encode(String.Format("{0:g}", item.ArticleDate)) %></div> <a class="news_delete" href="#" id="<%= item.ArticleID %>">Delete</a> </div> <div class="dno"></div> </div> <% } %> </div> </asp:Content> When trying to post new article I get following error: System.InvalidOperationException: The ViewData item that has the key 'CategoryId' is of type 'System.Int32' but must be of type 'IEnumerable'. I really don't know what to do cause I'm pretty new to .net and mvc Any help appreciated! Ile EDIT: I found where I made mistake. I didn't include date. If in view form I add this line I'm able to add article: <%=Html.Hidden("Date", String.Format("{0:g}", Model.NewArticle.Date)) %> But, if I enter wrong datetype or leave title and content empty then I get the same error. In this eample there is no need for date edit, but I will need it for some other forms and validation will be necessary. EDIT 2: Error happens when posting! Call stack: App_Web_of9beco9.dll!ASP.areas_cms_views_article_create_aspx.__RenderContent2(System.Web.UI.HtmlTextWriter __w = {System.Web.UI.HtmlTextWriter}, System.Web.UI.Control parameterContainer = {System.Web.UI.WebControls.ContentPlaceHolder}) Line 31 + 0x9f bytes C#

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