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  • Think before you animate

    - by David Paquette
    Animations are becoming more and more common in our applications.  With technologies like WPF, Silverlight and jQuery, animations are becoming easier for developers to use (and abuse).  When used properly, animation can augment the user experience.  When used improperly, animation can degrade the user experience.  Sometimes, the differences can be very subtle. I have recently made use of animations in a few projects and I very quickly realized how easy it is to abuse animation techniques.  Here are a few things I have learned along the way. 1) Don’t animate for the sake of animating We’ve all seen the PowerPoint slides with annoying slide transitions that animate 20 different ways.  It’s distracting and tacky.  The same holds true for your application.  While animations are fun and becoming easy to implement, resist the urge to use the technology just because you think the technology is amazing.   2) Animations should (and do) have meaning I recently built a simple Windows Phone 7 (WP7) application, Steeped (download it here).  The application has 2 pages.  The first page lists a number of tea types.  When the user taps on one of the tea types, the application navigates to the second page with information about that tea type and some options for the user to choose from.       One of the last things I did before submitting Steeped to the marketplace was add a page transition between the 2 pages.  I choose the Slide / Fade Out transition.  When the user selects a tea type, the main page slides to the left and fades out.  At the same time, the details page slides in from the right and fades in.  I tested it and thought it looked great so I submitted the app.  A few days later, I asked a friend to try the app.  He selected a tea type, and I was a little surprised by how he used the app.  When he wanted to navigate back to the main page, instead of pressing the back button on the phone, he tried to use a swiping gesture.  Of course, the swiping gesture did nothing because I had not implemented that feature.  After thinking about it for a while, I realized that the page transition I had chosen implied a particular behaviour.  As a user, if an action I perform causes an item (in this case the page) to move, then my expectation is that I should be able to move it back.  I have since added logic to handle the swipe gesture and I think the app flows much better now. When using animation, it pays to ask yourself:  What story does this animation tell my users?   3) Watch the replay Some animations might seem great initially but can get annoying over time.  When you use an animation in your application, make sure you try using it over and over again to make sure it doesn’t get annoying.  When I add an animation, I try watch it at least 25 times in a row.  After watching the animation repeatedly, I can make a more informed decision whether or not I should keep the animation.  Often, I end up shortening the length of the animations.   4) Don’t get in the users way An animation should never slow the user down.  When implemented properly, an animation can give a perceived bump in performance.  A good example of this is a the page transitions in most of the built in apps on WP7.  Obviously, these page animations don’t make the phone any faster, but they do provide a more responsive user experience.  Why?  Because most of the animations begin as soon as the user has performed some action.  The destination page might not be fully loaded yet, but the system responded immediately to user action, giving the impression that the system is more responsive.  If the user did not see anything happen until after the destination page was fully loaded, the application would feel clumsy and slow.  Also, it is important to make sure the animation does not degrade the performance (or perceived performance) of the application.   Jut a few things to consider when using animations.  As is the case with many technologies, we often learn how to misuse it before we learn how to use it effectively.

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  • MERGE gives better OUTPUT options

    - by Rob Farley
    MERGE is very cool. There are a ton of useful things about it – mostly around the fact that you can implement a ton of change against a table all at once. This is great for data warehousing, handling changes made to relational databases by applications, all kinds of things. One of the more subtle things about MERGE is the power of the OUTPUT clause. Useful for logging.   If you’re not familiar with the OUTPUT clause, you really should be – it basically makes your DML (INSERT/DELETE/UPDATE/MERGE) statement return data back to you. This is a great way of returning identity values from INSERT commands (so much better than SCOPE_IDENTITY() or the older (and worse) @@IDENTITY, because you can get lots of rows back). You can even use it to grab default values that are set using non-deterministic functions like NEWID() – things you couldn’t normally get back without running another query (or with a trigger, I guess, but that’s not pretty). That inserted table I referenced – that’s part of the ‘behind-the-scenes’ work that goes on with all DML changes. When you insert data, this internal table called inserted gets populated with rows, and then used to inflict the appropriate inserts on the various structures that store data (HoBTs – the Heaps or B-Trees used to store data as tables and indexes). When deleting, the deleted table gets populated. Updates get a matching row in both tables (although this doesn’t mean that an update is a delete followed by an inserted, it’s just the way it’s handled with these tables). These tables can be referenced by the OUTPUT clause, which can show you the before and after for any DML statement. Useful stuff. MERGE is slightly different though. With MERGE, you get a mix of entries. Your MERGE statement might be doing some INSERTs, some UPDATEs and some DELETEs. One of the most common examples of MERGE is to perform an UPSERT command, where data is updated if it already exists, or inserted if it’s new. And in a single operation too. Here, you can see the usefulness of the deleted and inserted tables, which clearly reflect the type of operation (but then again, MERGE lets you use an extra column called $action to show this). (Don’t worry about the fact that I turned on IDENTITY_INSERT, that’s just so that I could insert the values) One of the things I love about MERGE is that it feels almost cursor-like – the UPDATE bit feels like “WHERE CURRENT OF …”, and the INSERT bit feels like a single-row insert. And it is – but into the inserted and deleted tables. The operations to maintain the HoBTs are still done using the whole set of changes, which is very cool. And $action – very convenient. But as cool as $action is, that’s not the point of my post. If it were, I hope you’d all be disappointed, as you can’t really go near the MERGE statement without learning about it. The subtle thing that I love about MERGE with OUTPUT is that you can hook into more than just inserted and deleted. Did you notice in my earlier query that my source table had a ‘src’ field, that wasn’t used in the insert? Normally, this would be somewhat pointless to include in my source query. But with MERGE, I can put that in the OUTPUT clause. This is useful stuff, particularly when you’re needing to audit the changes. Suppose your query involved consolidating data from a number of sources, but you didn’t need to insert that into the actual table, just into a table for audit. This is now very doable, either using the INTO clause of OUTPUT, or surrounding the whole MERGE statement in brackets (parentheses if you’re American) and using a regular INSERT statement. This is also doable if you’re using MERGE to just do INSERTs. In case you hadn’t realised, you can use MERGE in place of an INSERT statement. It’s just like the UPSERT-style statement we’ve just seen, except that we want nothing to match. That’s easy to do, we just use ON 1=2. This is obviously more convoluted than a straight INSERT. And it’s slightly more effort for the database engine too. But, if you want the extra audit capabilities, the ability to hook into the other source columns is definitely useful. Oh, and before people ask if you can also hook into the target table’s columns... Yes, of course. That’s what deleted and inserted give you.

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  • My Feelings About Microsoft Surface

    - by Valter Minute
    Advice: read the title carefully, I’m talking about “feelings” and not about advanced technical points proved in a scientific and objective way I still haven’t had a chance to play with a MS Surface tablet (I would love to, of course) and so my ideas just came from reading different articles on the net and MS official statements. Remember also that the MVP motto begins with “Independent” (“Independent Experts. Real World Answers.”) and this is just my humble opinion about a product and a technology. I know that, being an MS MVP you can be called an “MS-fanboy”, I don’t care, I hope that people can appreciate my opinion, even if it doesn’t match theirs. The “Surface” brand can be confusing for techies that knew the “original” surface concept but I think that will be a fresh new brand name for most of the people out there. But marketing department are here to confuse people… so I can understand this “recycle” of an existing name. So Microsoft is entering the hardware arena… for me this is good news. Microsoft developed some nice hardware in the past: the xbox, zune (even if the commercial success was quite limited) and, last but not least, the two arc mices (old and new model) that I use and appreciate. In the past Microsoft worked with OEMs and that model lead to good and bad things. Good thing (for microsoft, at least) is market domination by windows-based PCs that only in the last years has been reduced by the return of the Mac and tablets. Google is also moving in the hardware business with its acquisition of Motorola, and Apple leveraged his control of both the hardware and software sides to develop innovative products. Microsoft can scare OEMs and make them fly away from windows (but where?) or just lead the pack, showing how devices should be designed to compete in the market and bring back some of the innovation that disappeared from recent PC products (look at the shelves of your favorite electronics store and try to distinguish a laptop between the huge mass of anonymous PCs on displays… only Macs shine out there…). Having to compete with MS “official” hardware will force OEMs to develop better product and bring back some real competition in a market that was ruled only by prices (the lower the better even when that means low quality) and no innovative features at all (when it was the last time that a new PC surprised you?). Moving into a new market is a big and risky move, but with Windows 8 Microsoft is playing a crucial move for its future, trying to be back in the innovation run against apple and google. MS can’t afford to fail this time. I saw the new devices (the WinRT and Pro) and the specifications are scarce, misleading and confusing. The first impression is that the device looks like an iPad with a nice keyboard cover… Using “HD” and “full HD” to define display resolution instead of using the real figures and reviving the “ClearType” brand (now dead on Win8 as reported here and missed by people who hate to read text on displays, like myself) without providing clear figures (couldn’t you count those damned pixels?) seems to imply that MS was caught by surprise by apple recent “retina” displays that brought very high definition screens on tablets.Also there are no specifications about the processors used (even if some sources report NVidia Tegra for the ARM tablet and i5 for the x86 one) and expected battery life (a critical point for tablets and the point that killed Windows7 x86 based tablets). Also nothing about the price, and this will be another critical point because other platform out there already provide lots of applications and have a good user base, if MS want to enter this market tablets pricing must be competitive. There are some expansion ports (SD and USB), so no fixed storage model (even if the specs talks about 32-64GB for RT and 128-256GB for pro). I like this and don’t like the apple model where flash memory (that it’s dirt cheap used in thumdrives or SD cards) is as expensive as gold (or cocaine to have a more accurate per gram measurement) when mounted inside a tablet/phone. For big files you’ll be able to use external media and an SD card could be used to store files that don’t require super-fast SSD-like access times, I hope. To be honest I really don’t like the marketplace model and the limitation of Windows RT APIs (no local database? from a company that based a good share of its success on VB6+Access!) and lack of desktop support on the ARM (even if the support is here and has been used to port office). It’s a step toward the consumer market (where competitors are making big money), but may impact enterprise (and embedded) users that may not appreciate Windows 8 new UI or the limitations of the new app model (if you aren’t connected you are dead ). Not having compatibility with the desktop will require brand new applications and honestly made all the CPU cycles spent to convert .NET IL into real machine code in the past like a huge waste of time… as soon as a new processor architecture is supported by Windows you still have to rewrite part of your application (and MS is pushing HTML5+JS and native code more than .NET in my perception). On the other side I believe that the development experience provided by Visual Studio is still miles (or kilometres) ahead of the competition and even the all-uppercase menu of VS2012 hasn’t changed this situation. The new metro UI got mixed reviews. On my side I should say that is very pleasant to use on a touch screen, I like the minimalist design (even if sometimes is too minimal and hides stuff that, in my opinion, should be visible) but I should also say that using it with mouse and keyboard is like trying to pick your nose with boxing gloves… Metro is also very interesting for embedded devices where touch screen usage is quite common and where having an application taking all the screen is the norm. For devices like kiosks, vending machines etc. this kind of UI can be a great selling point. I don’t need a new tablet (to be honest I’m pretty happy with my wife’s iPad and with my PC), but I may change my opinion after having a chance to play a little bit with those new devices and understand what’s hidden under all this mysterious and generic announcements and specifications!

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  • Rebuilding CoasterBuzz, Part II: Hot data objects

    - by Jeff
    This is the second post, originally from my personal blog, in a series about rebuilding one of my Web sites, which has been around for 12 years. More: Part I: Evolution, and death to WCF After the rush to get moving on stuff, I temporarily lost interest. I went almost two weeks without touching the project, in part because the next thing on my backlog was doing up a bunch of administrative pages. So boring. Unfortunately, because most of the site's content is user-generated, you need some facilities for editing data. CoasterBuzz has a database full of amusement parks and roller coasters. The entities enjoy the relationships that you would expect, though they're further defined by "instances" of a coaster, to define one that has moved between parks as one, with different names and operational dates. And of course, there are pictures and news items, too. It's not horribly complex, except when you have to account for a name change and display just the newest name. In all previous versions, data access was straight SQL. As so much of the old code was rooted in 2003, with some changes in 2008, there wasn't much in the way of ORM frameworks going on then. Let me rephrase that, I mostly wasn't interested in ORM's. Since that time, I used a little LINQ to SQL in some projects, and a whole bunch of nHibernate while at Microsoft. Through all of that experience, I have to admit that these frameworks are often a bigger pain in the ass than not. They're great for basic crud operations, but when you start having all kinds of exotic relationships, they get difficult, and generate all kinds of weird SQL under the covers. The black box can quickly turn into a black hole. Sometimes you end up having to build all kinds of new expertise to do things "right" with a framework. Still, despite my reservations, I used the newer version of Entity Framework, with the "code first" modeling, in a science project and I really liked it. Since it's just a right-click away with NuGet, I figured I'd give it a shot here. My initial effort was spent defining the context class, which requires a bit of work because I deviate quite a bit from the conventions that EF uses, starting with table names. Then throw some partial querying of certain tables (where you'll find image data), and you're splitting tables across several objects (navigation properties). I won't go into the details, because these are all things that are well documented around the Internet, but there was a minor learning curve there. The basics of reading data using EF are fantastic. For example, a roller coaster object has a park associated with it, as well as a number of instances (if it was ever relocated), and there also might be a big banner image for it. This is stupid easy to use because it takes one line of code in your repository class, and by the time you pass it to the view, you have a rich object graph that has everything you need to display stuff. Likewise, editing simple data is also, well, simple. For this goodness, thank the ASP.NET MVC framework. The UpdateModel() method on the controllers is very elegant. Remember the old days of assigning all kinds of properties to objects in your Webforms code-behind? What a time consuming mess that used to be. Even if you're not using an ORM tool, having hydrated objects come off the wire is such a time saver. Not everything is easy, though. When you have to persist a complex graph of objects, particularly if they were composed in the user interface with all kinds of AJAX elements and list boxes, it's not just a simple matter of submitting the form. There were a few instances where I ended up going back to "old-fashioned" SQL just in the interest of time. It's not that I couldn't do what I needed with EF, it's just that the efficiency, both my own and that of the generated SQL, wasn't good. Since EF context objects expose a database connection object, you can use that to do the old school ADO.NET stuff you've done for a decade. Using various extension methods from POP Forums' data project, it was a breeze. You just have to stick to your decision, in this case. When you start messing with SQL directly, you can't go back in the same code to messing with entities because EF doesn't know what you're changing. Not really a big deal. There are a number of take-aways from using EF. The first is that you write a lot less code, which has always been a desired outcome of ORM's. The other lesson, and I particularly learned this the hard way working on the MSDN forums back in the day, is that trying to retrofit an ORM framework into an existing schema isn't fun at all. The CoasterBuzz database isn't bad, but there are design decisions I'd make differently if I were starting from scratch. Now that I have some of this stuff done, I feel like I can start to move on to the more interesting things on the backlog. There's a lot to do, but at least it's fun stuff, and not more forms that will be used infrequently.

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  • how to label a cuboid using open gl?

    - by usha
    hi this is how my 3dcuboid looks ,i have attached complete code , i want to label this cuboid using different name across sides how is it possible using opengl in android...plz help me out public class MyGLRenderer implements Renderer { Context context; Cuboid rect; private float mCubeRotation; // private static float angleCube = 0; // Rotational angle in degree for cube (NEW) // private static float speedCube = -1.5f; // Rotational speed for cube (NEW) public MyGLRenderer(Context context) { rect = new Cuboid(); this.context = context; } public void onDrawFrame(GL10 gl) { // TODO Auto-generated method stub gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); gl.glLoadIdentity(); // Reset the model-view matrix gl.glTranslatef(0.2f, 0.0f, -8.0f); // Translate right and into the screen gl.glScalef(0.8f, 0.8f, 0.8f); // Scale down (NEW) gl.glRotatef(mCubeRotation, 1.0f, 1.0f, 1.0f); // gl.glRotatef(angleCube, 1.0f, 1.0f, 1.0f); // rotate about the axis (1,1,1) (NEW) rect.draw(gl); mCubeRotation -= 0.15f; //angleCube += speedCube; } public void onSurfaceChanged(GL10 gl, int width, int height) { // TODO Auto-generated method stub if (height == 0) height = 1; // To prevent divide by zero float aspect = (float)width / height; // Set the viewport (display area) to cover the entire window gl.glViewport(0, 0, width, height); // Setup perspective projection, with aspect ratio matches viewport gl.glMatrixMode(GL10.GL_PROJECTION); // Select projection matrix gl.glLoadIdentity(); // Reset projection matrix // Use perspective projection GLU.gluPerspective(gl, 45, aspect, 0.1f, 100.f); gl.glMatrixMode(GL10.GL_MODELVIEW); // Select model-view matrix gl.glLoadIdentity(); // Reset } public void onSurfaceCreated(GL10 gl, EGLConfig config) { // TODO Auto-generated method stub gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Set color's clear-value to black gl.glClearDepthf(1.0f); // Set depth's clear-value to farthest gl.glEnable(GL10.GL_DEPTH_TEST); // Enables depth-buffer for hidden surface removal gl.glDepthFunc(GL10.GL_LEQUAL); // The type of depth testing to do gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST); // nice perspective view gl.glShadeModel(GL10.GL_SMOOTH); // Enable smooth shading of color gl.glDisable(GL10.GL_DITHER); // Disable dithering for better performance }} public class Cuboid{ private FloatBuffer mVertexBuffer; private FloatBuffer mColorBuffer; private ByteBuffer mIndexBuffer; private float vertices[] = { //width,height,depth -2.5f, -1.0f, -1.0f, 1.0f, -1.0f, -1.0f, 1.0f, 1.0f, -1.0f, -2.5f, 1.0f, -1.0f, -2.5f, -1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 1.0f, 1.0f, 1.0f, -2.5f, 1.0f, 1.0f }; private float colors[] = { // R,G,B,A COLOR 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.5f, 0.0f, 1.0f, 1.0f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f }; private byte indices[] = { // VERTEX 0,1,2,3,4,5,6,7 REPRESENTATION FOR FACES 0, 4, 5, 0, 5, 1, 1, 5, 6, 1, 6, 2, 2, 6, 7, 2, 7, 3, 3, 7, 4, 3, 4, 0, 4, 7, 6, 4, 6, 5, 3, 0, 1, 3, 1, 2 }; public Cuboid() { ByteBuffer byteBuf = ByteBuffer.allocateDirect(vertices.length * 4); byteBuf.order(ByteOrder.nativeOrder()); mVertexBuffer = byteBuf.asFloatBuffer(); mVertexBuffer.put(vertices); mVertexBuffer.position(0); byteBuf = ByteBuffer.allocateDirect(colors.length * 4); byteBuf.order(ByteOrder.nativeOrder()); mColorBuffer = byteBuf.asFloatBuffer(); mColorBuffer.put(colors); mColorBuffer.position(0); mIndexBuffer = ByteBuffer.allocateDirect(indices.length); mIndexBuffer.put(indices); mIndexBuffer.position(0); } public void draw(GL10 gl) { gl.glFrontFace(GL10.GL_CW); gl.glVertexPointer(3, GL10.GL_FLOAT, 0, mVertexBuffer); gl.glColorPointer(4, GL10.GL_FLOAT, 0, mColorBuffer); gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glEnableClientState(GL10.GL_COLOR_ARRAY); gl.glDrawElements(GL10.GL_TRIANGLES, 36, GL10.GL_UNSIGNED_BYTE, mIndexBuffer); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_COLOR_ARRAY); } } public class Draw3drect extends Activity { private GLSurfaceView glView; // Use GLSurfaceView // Call back when the activity is started, to initialize the view @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); glView = new GLSurfaceView(this); // Allocate a GLSurfaceView glView.setRenderer(new MyGLRenderer(this)); // Use a custom renderer this.setContentView(glView); // This activity sets to GLSurfaceView } // Call back when the activity is going into the background @Override protected void onPause() { super.onPause(); glView.onPause(); } // Call back after onPause() @Override protected void onResume() { super.onResume(); glView.onResume(); } }

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  • WMemoryProfiler is Released

    - by Alois Kraus
    What is it? WMemoryProfiler is a managed profiling Api to aid integration testing. This free library can get managed heap statistics and memory usage for your own process (remember testing) and other processes as well. The best thing is that it does work from .NET 2.0 up to .NET 4.5 in x86 and x64. To make it more interesting it can attach to any running .NET process. The reason why I do mention this is that commercial profilers do support this functionality only for their professional editions. An normally only since .NET 4.0 since the profiling API only since then does support attaching to a running process. This thing does differ in many aspects from “normal” profilers because while profiling yourself you can get all objects from all managed heaps back as an object array. If you ever wanted to change the state of an object which does only exist a method local in another thread you can get your hands on it now … Enough theory. Show me some code /// <summary> /// Show feature to not only get statisics out of a process but also the newly allocated /// instances since the last call to MarkCurrentObjects. /// GetNewObjects does return the newly allocated objects as object array /// </summary> static void InstanceTracking() { using (var dumper = new MemoryDumper()) // if you have problems use to see the debugger windows true,true)) { dumper.MarkCurrentObjects(); Allocate(); ILookup<Type, object> newObjects = dumper.GetNewObjects() .ToLookup( x => x.GetType() ); Console.WriteLine("New Strings:"); foreach (var newStr in newObjects[typeof(string)] ) { Console.WriteLine("Str: {0}", newStr); } } } … New Strings: Str: qqd Str: String data: Str: String data: 0 Str: String data: 1 … This is really hot stuff. Not only you can get heap statistics but you can directly examine the new objects and make queries upon them. When I do find more time I can reconstruct the object root graph from it from my own process. It this cool or what? You can also peek into the Finalization Queue to check if you did accidentally forget to dispose a whole bunch of objects … /// <summary> /// .NET 4.0 or above only. Get all finalizable objects which are ready for finalization and have no other object roots anymore. /// </summary> static void NotYetFinalizedObjects() { using (var dumper = new MemoryDumper()) { object[] finalizable = dumper.GetObjectsReadyForFinalization(); Console.WriteLine("Currently {0} objects of types {1} are ready for finalization. Consider disposing them before.", finalizable.Length, String.Join(",", finalizable.ToLookup( x=> x.GetType() ) .Select( x=> x.Key.Name)) ); } } How does it work? The W of WMemoryProfiler is a good hint. It does employ Windbg and SOS dll to do the heavy lifting and concentrates on an easy to use Api which does hide completely Windbg. If you do not want to see Windbg you will never see it. In my experience the most complex thing is actually to download Windbg from the Windows 8 Stanalone SDK. This is described in the Readme and the exception you are greeted with if it is missing in much greater detail. So I will not go into this here.   What Next? Depending on the feedback I do get I can imagine some features which might be useful as well Calculate first order GC Roots from the actual object graph Identify global statics in Types in object graph Support read out of finalization queue of .NET 2.0 as well. Support Memory Dump analysis (again a feature only supported by commercial profilers in their professional editions if it is supported at all) Deserialize objects from a memory dump into a live process back (this would need some more investigation but it is doable) The last item needs some explanation. Why on earth would you want to do that? The basic idea is to store in your live process some logging/tracing data which can become quite big but since it is never written to it is very fast to generate. When your process crashes with a memory dump you could transfer this data structure back into a live viewer which can then nicely display your program state at the point it did crash. This is an advanced trouble shooting technique I have not seen anywhere yet but it could be quite useful. You can have here a look at the current feature list of WMemoryProfiler with some examples.   How To Get Started? First I would download the released source package (it is tiny). And compile the complete project. Then you can compile the Example project (it has this name) and uncomment in the main method the scenario you want to check out. If you are greeted with an exception it is time to install the Windows 8 Standalone SDK which is described in great detail in the exception text. Thats it for the first round. I have seen something more limited in the Java world some years ago (now I cannot find the link anymore) but anyway. Now we have something much better.

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  • Coherence Data Guarantees for Data Reads - Basic Terminology

    - by jpurdy
    When integrating Coherence into applications, each application has its own set of requirements with respect to data integrity guarantees. Developers often describe these requirements using expressions like "avoiding dirty reads" or "making sure that updates are transactional", but we often find that even in a small group of people, there may be a wide range of opinions as to what these terms mean. This may simply be due to a lack of familiarity, but given that Coherence sits at an intersection of several (mostly) unrelated fields, it may be a matter of conflicting vocabularies (e.g. "consistency" is similar but different in transaction processing versus multi-threaded programming). Since almost all data read consistency issues are related to the concept of concurrency, it is helpful to start with a definition of that, or rather what it means for two operations to be concurrent. Rather than implying that they occur "at the same time", concurrency is a slightly weaker statement -- it simply means that it can't be proven that one event precedes (or follows) the other. As an example, in a Coherence application, if two client members mutate two different cache entries sitting on two different cache servers at roughly the same time, it is likely that one update will precede the other by a significant amount of time (say 0.1ms). However, since there is no guarantee that all four members have their clocks perfectly synchronized, and there is no way to precisely measure the time it takes to send a given message between any two members (that have differing clocks), we consider these to be concurrent operations since we can not (easily) prove otherwise. So this leads to a question that we hear quite frequently: "Are the contents of the near cache always synchronized with the underlying distributed cache?". It's easy to see that if an update on a cache server results in a message being sent to each near cache, and then that near cache being updated that there is a window where the contents are different. However, this is irrelevant, since even if the application reads directly from the distributed cache, another thread update the cache before the read is returned to the application. Even if no other member modifies a cache entry prior to the local near cache entry being updated (and subsequently read), the purpose of reading a cache entry is to do something with the result, usually either displaying for consumption by a human, or by updating the entry based on the current state of the entry. In the former case, it's clear that if the data is updated faster than a human can perceive, then there is no problem (and in many cases this can be relaxed even further). For the latter case, the application must assume that the value might potentially be updated before it has a chance to update it. This almost aways the case with read-only caches, and the solution is the traditional optimistic transaction pattern, which requires the application to explicitly state what assumptions it made about the old value of the cache entry. If the application doesn't want to bother stating those assumptions, it is free to lock the cache entry prior to reading it, ensuring that no other threads will mutate the entry, a pessimistic approach. The optimistic approach relies on what is sometimes called a "fuzzy read". In other words, the application assumes that the read should be correct, but it also acknowledges that it might not be. (I use the qualifier "sometimes" because in some writings, "fuzzy read" indicates the situation where the application actually sees an original value and then later sees an updated value within the same transaction -- however, both definitions are roughly equivalent from an application design perspective). If the read is not correct it is called a "stale read". Going back to the definition of concurrency, it may seem difficult to precisely define a stale read, but the practical way of detecting a stale read is that is will cause the encompassing transaction to roll back if it tries to update that value. The pessimistic approach relies on a "coherent read", a guarantee that the value returned is not only the same as the primary copy of that value, but also that it will remain that way. In most cases this can be used interchangeably with "repeatable read" (though that term has additional implications when used in the context of a database system). In none of cases above is it possible for the application to perform a "dirty read". A dirty read occurs when the application reads a piece of data that was never committed. In practice the only way this can occur is with multi-phase updates such as transactions, where a value may be temporarily update but then withdrawn when a transaction is rolled back. If another thread sees that value prior to the rollback, it is a dirty read. If an application uses optimistic transactions, dirty reads will merely result in a lack of forward progress (this is actually one of the main risks of dirty reads -- they can be chained and potentially cause cascading rollbacks). The concepts of dirty reads, fuzzy reads, stale reads and coherent reads are able to describe the vast majority of requirements that we see in the field. However, the important thing is to define the terms used to define requirements. A quick web search for each of the terms in this article will show multiple meanings, so I've selected what are generally the most common variations, but it never hurts to state each definition explicitly if they are critical to the success of a project (many applications have sufficiently loose requirements that precise terminology can be avoided).

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  • 2012&ndash;The End Of The World Review

    - by Tim Murphy
    The end of the world must be coming.  Not because the Mayan calendar says so, but because Microsoft is innovating more than Apple.  It has been a crazy year, with pundits declaring not that the end of the world is coming, but that the end of Microsoft is coming.  Let’s take a look at what 2012 has brought us. The beginning of year is a blur.  I managed to get to TechEd in June which was the first time that I got to take a deep dive into Windows 8 and many other things that had been announced in 2011.  The promise I saw in these products was really encouraging.  The thought of being able to run Windows 8 from a thumb drive or have Hyper-V native to the OS told me that at least for developers good things were coming. I finally got my feet wet with Windows 8 with the developer preview just prior to the RTM.  While the initial experience was a bit of a culture shock I quickly grew to love it.  The media still seems to hold little love for the “reimagined” platform, but I think that once people spend some time with it they will enjoy the experience and what the FUD mongers say will fade into the background.  With the launch of the OS we finally got a look at the Surface.  I think this is a bold entry into the tablet market.  While I wish it was a little more affordable I am already starting to see them in the wild being used by non-techies. I was waiting for Windows Phone 8 at least as much as Windows 8, probably more.  The new hardware, better marketing and new OS features I think are going to finally push us to the point of having a real presence in the smartphone market.  I am seeing a number of iPhone users picking up a Nokia Lumia 920 and getting rid of their brand new iPhone 5.  The only real debacle that I saw around the launch was when they held back the SDK from general developers. Shortly after the launch events came Build 2012.  I was extremely disappointed that I didn’t make it to this year’s Build.  Even if they weren’t handing out Surface and Lumia devices I think the atmosphere and content were something that really needed to be experience in person.  Hopefully there will be a Build next year and it’s schedule will be announced soon.  As you would expect Windows 8 and Windows Phone 8 development were the mainstay of the conference, but improvements in Azure also played a key role.  This movement of services to the cloud will continue and we need to understand where it best fits into the solutions we build. Lower on the radar this year were Office 2013, SQL Server 2012, and Windows Server 2012.  Their glory stolen by the consumer OS and hardware announcements, these new releases are no less important.  Companies will see significant improvements in performance and capabilities if they upgrade.  At TechEd they had shown some of the new features of Windows Server 2012 around hardware integration and Hyper-V performance which absolutely blew me away.  It is our job to bring these important improvements to our company’s attention so that they can be leveraged. Personally, the consulting business in 2012 was the busiest it has been in a long time.  More companies were ready to attack new projects after several years of putting them on the back burner.  I also worked to bring back momentum to the Chicago Information Technology Architects Group.  Both the community and clients are excited about the new technologies that have come out in 2012 and now it is time to deliver. What does 2013 have in store.  I don’t see it be quite as exciting as 2012.  Microsoft will be releasing the Surface Pro in January and it seems that we will see more frequent OS update for Windows.  There are rumors that we may see a Surface phone in 2013.  It has also been announced that there will finally be a rework of the XBox next fall.  The new year will also be a time for us in the development community to take advantage of these new tools and devices.  After all, it is what we build on top of these platforms that will attract more consumers and corporations to using them. Just as I am 99.999% sure that the world is not going to end this year, I am also sure that Microsoft will move on and that most of this negative backlash from the media is actually fear and jealousy.  In the end I think we have a promising year ahead of us. del.icio.us Tags: Microsoft,Pundits,Mayans,Windows 8,Windows Phone 8,Surface

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  • Install Control Center Agent on Oracle Application Server

    - by qianqian.wu
    Control Center Agent (CCA) The Control Center Agent is the OWB component that runs the Template Mappings in the Oracle Containers for J2EE (OC4J) server; also referred to as the J2EE Runtime. The Control Center Agent provides a Java-based runtime environment that can be installed on Oracle and non-Oracle database hosts. The Control Center Agent provides fundamental infrastructure for the heterogeneous, Code Template-based mapping support and Web services-related features of OWB in this release. In Oracle Warehouse Builder 11gR2 the Control Center Agent, by default will run in the built-in OC4J that is bundled in the Oracle Home. Besides that, you also have ability to install the Control Center Agent in an Oracle Application Server install. In this article, you will find step-by-step instructions how to install the Control Center Agent on an Oracle Application Server instance. The instructions cover the following tasks: Task 1: Install and Configure the Application Server Task 2: Deploy the Control Center Agent to the Application Server Task 3: Optional Configuration Tasks   Task 1: Install and Configure the Application Server Before configuring the Application Server, you need to install it from Oracle Application Server CD-ROM, or by downloading the installation program from Oracle Technology Network (OTN). Once the installation is completed, you are ready to configure the Application Server. The purpose of the configuration task is to make sure the Control Center Agent ear file can be deployed and runs in the Application Server successfully. The essential configuration tasks are outlined below: · Modify the OC4J Startup Script · Set up Control Center Agent Server Side Logging · Set up Audit Table Data Source · Copy ct_permissions.properties File · Set up Security Roles for Control Center Agent · Create JMS Queues · Install JDBC Drivers to OC4J Modify the OC4J Startup Script The OC4J startup script “opmn.xml” is located in Application Server configuration directory, $AS_HOME/opmn/conf. $AS_HOME stands for the root home directory of the application server. Open the file opmn.xml in a text editor, and alter the contents of the file as displayed in the following sample. You need to make sure that: The MaxPerSize is set to 128M. This is to ensure that you allocate enough PermGen space to OC4J to run Control Center Agent. This will prevent java.lang.OutOfMemoryError when running the agent. The Python.path sets the path for the Python library files used by the Control Center Agent: jython_lib.zip and jython_owblib.jar. These two files are in the $OWB_HOME/owb/lib/int directory, where $OWB_HOME is the directory where owb is installed. · The km_security_needed determines whether restrictions will be applied to the kinds of operating system commands allowed to be executed by the OWB Code Template script executed by Control Center Agent. Setting km_security_needed to “true” enforces such restriction while setting it to “false” removes such restrictions. Set up Control Center Agent Server Side Logging Ensure that you are in the Application Server configuration directory, $AS_HOME/j2ee/home/config. Open the file j2ee-logging.xml in a text editor and add the following lines to the log handler section. The jrt-internal-log-handler is the handler used by Control Center Agent runtime logger to create log files. Then add the following entry into the loggers section to create the logger for Control Center Agent runtime auditing. Set up Audit Table Data Source To enable Audit Table logging, a managed data source and connection pool need to be set up before Control Center Agent deployment. Ensure that you are in the Application Server configuration directory, $AS_HOME/j2ee/home/config. Open the file data-sources.xml in a text editor. Define the audit data source shown below in the file, <managed-data-source name="AuditDS" connection-pool-name="OWBSYS Audit   Connection Pool" jndi-name="jdbc/AuditDS"/> <connection-pool name="OWBSYS Audit Connection Pool">   <connection-factory factory-class="oracle.jdbc.pool.OracleDataSource"     user="owbsys_audit" password="owbsys_audit"     url="jdbc:oracle:thin:@//localhost:1521/ORCL"/> </connection-pool> Copy ct_permissions.properties File The ct_permissions.properties can be obtained from $OWB_HOME /owb/jrt/config/ directory. You need to copy the file to $AS_HOME/j2ee/home/config directory.This properties file takes effect when the setting km-security is set to true in Control Center Agent. By default the ALLOWED_CMD is commented out in ct_permissions.properties file. This prevents all system command from being invoked from scripts executed in Control Center Agent (when km-security is set to true). To allow certain system commands to be invoked, ALLOWED_CMD needs to be uncommented out, and the system commands (allowed to be invoked) need to be added to the ALLOWED_CMD. Set up Security Roles for Control Center Agent You can set up the Control Center Agent security roles through Oracle Enterprise Manager. In a web browser, navigate to Enterprise Manager Homepage (e.g. http://hostname:8889/em). 1. Log in using the oc4jadmin credentials. After the Cluster Topology page is loaded, click home (the OC4J instance). This takes you to the home page of the OC4J instance. On the OC4J home screen, click the Administration tab. On the Administration Tasks screen, expand Security. Click the task icon next to Security Providers. 2. On Security Providers page click on the button “Instance Level Security”. On Instance Level Security page, go to “Realms” tab. You will see a row for the default realm “jazn.com” in the results table. It has a “Roles” column and a “Users” column. Click on the number in “Roles” column. In the “Roles” page it will display all the roles available for the realm. Click on “Create” button to create a new role “OWB_J2EE_ EXECUTOR”. 3. On the Add Role screen, enter Name OWB_J2EE_EXECUTOR, and click OK. 4. Follow the same steps as before, and create a new role “OWB_J2EE_OPERATOR”. 5. Assign role “oc4j-administrators” and “OWB_J2EE_EXECUTOR” to the role “OWB_J2EE_OPERATOR” by moving these roles from “Available Roles” and click “OK” to save. 6. Go back to Instance Level Security page and create a new role “OWB_J2EE_ADMINISTRATOR”. 7. Assign roles “OWB_J2EE_ OPERATOR” and “OWB_J2EE_EXECUTOR” to the role “OWB_J2EE_ ADMINISTRATOR” by moving these roles from “Available Roles” and click “OK” to save. 8.Go back to Instance Level Security page. This time, click on the number in “Users” column for the realm “jazn.com”. In the “Users” page, it shows all the users defined for this realm. Locate the user “oc4jadmin” in the results table and click on it. 9. Assign the roles “OWB_J2EE_ADMINISTRATOR” and “oc4j-app-administrators” to this user by moving the role from the “Available Roles” selection box to “Selected Roles” box and click “Apply” to save. 10. Go back to Instance Level Security page and create a new role “OWB_INTERNAL_USERS”, assign no user or role to this role. Simply click “OK” to create this role. Now you have finished creating the security roles required for Control Center Agent. Create JMS Queues You need to create two JMS queues for Control Center Agent: owbQueue and abort_owbQueue. 1. Now go to OC4J home Page. On the OC4J home screen, click the Administration tab. On the Administration Tasks screen, expand Services and then expand Enterprise Messaging Service. Click the task icon next to JMS Destinations. 2. On JMS Destinations page, click “Create New” button to create a new JMS queue. On Add Destination page, choose “Queue” as Destination Type. Put “owbQueue” as Destination Name. Select “In Memory Persistence Only” as the Persistence Type and put “jms/owbQueue” as JNDI Location and click on “OK” to finish. 3. Follow the same instruction as above to create the owb_abortQueue. Now you have finished creating the JMS queues required for Control Center Agent. Install JDBC Drivers to OC4J In order to execute Code Templates using commercial databases other than Oracle, e.g. DB2, SQL Server etc, the corresponding jdbc driver files need to be added to $AS_HOME/j2ee/home/applib directory. 1. To install other JDBC drivers to OC4J, first obtain the .jar file containing the JDBC driver. All the external JDBC drivers .jar files can be found in the directory: $OWB_HOME/owb/lib/ext/. For DB2, the files needed are db2jcc.jar and db2jcc_license_cu.jar. For SQL Server the file is sqljdbc.jar. For sunopsis JDBC drivers, the file needed is snpsxmlo.jar. 2. Copy the required JDBC driver file into the directory $AS_HOME/j2ee/home/applib. Now you have finished the Application Server configuration. To make the configuration to take an effect, you need to restart the Application Server.   Task 2: Deploy the Control Center Agent to the Application Server Now you can deploy the Control Center Agent to the Application Server. In a web browser, navigate to Enterprise Manager Homepage (e.g. http://hostname:8889/em). 1. Log in using the oc4jadmin credentials. After the Cluster Topology page is loaded, click home (the OC4J instance). This takes you to the home page of the OC4J instance. On the OC4J home screen, click the Applications tab. Click Deploy to begin deploying Control Center Agent. 2. On the Deploy: Select Archive screen, under Archive, select Archive is present on local host. Upload the archive to the server where Application Server Control is running. Click Browse and locate the jrt.ear file in the $OWB_HOME/owb/jrt/applications directory. Under Deployment Plan, select Automatically create a new deployment plan. Click Next. 3. Wait for the ear file to be uploaded to Application Server. On the Deploy: Application Attributes screen, enter Application Name jrt, and Context Root jrt. Leave the other attributes at their default values. Click Next. 4. On Deploy: Deployment Settings screen, leave all attributes at their default values, and click Deploy. This will take about 1 minute or so and when the application is deployed successfully, a confirmation message will be displayed. Now the Control Center Agent is started automatically. Go back to OC4J home page and click on Applications tab to make sure the deployed application jrt is showing in the applications list.   Task 3: Optional Configuration Tasks The optional configuration tasks contain: · Secure Control Center Agent Web Service · Setting the PATH Environment Variable Secure Control Center Agent Web Service If you want to use JRTWebService with a secure website, you need to do the following steps, 1. Create a file “secure-web-site.xml” in the $AS_HOME/j2ee/home/config directory. The file can be obtained from $OWB_HOME/owb/jrt/config directory. A sample secure-web-site.xml is shown as below. We need to modify the “protocol” to “https”, and “secure” to “true”, also choose an port as the secure http port. Also we need to add the entry “ssl-config” in the file. Remember to use the absolute path for the key store file. 2. Modify the file “server.xml” that is located at $AS_HOME/j2ee/home/config directory. Then add the <web-site> element in the file for the secure-web-site. 3. Create a key store file “serverkeystore.jks” in the $AS_HOME/j2ee/home/config directory. The file can be obtained from $OWB_HOME/owb/jrt/config directory. After the three files are altered, restart the application server. Now you can access the JRTWebService in SSL way through https://hostname:4443/jrt/webservice. Setting the PATH Environment Variable Sometimes, some system commands such as linux ls, sh etc, can not be executed successfully during the script execution due to they are not found in PATH. To ensure they work normally, you can setup the environment variable PATH. Let’s navigate to the Enterprise Manager Homepage. 1. Go to OC4J home screen and click the Administration tab. Expand Administration Tasks, then expand Properties. Click the task icon next to Server Properties. 2. On the Server Properties screen, scroll down to Environment Variables section. Under Environment Variables, click Add Another Row. Enter PATH in Name, and fill Value with directories that contain the system commands. Click Apply.   After you work through this article, I believe you have developed a deeper understanding of the Control Center Agent installation process, and you can apply this knowledge in other installation plan such as Control Center Agent installation on Standalone OC4J.

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  • How to create a new WCF/MVC/jQuery application from scratch

    - by pjohnson
    As a corporate developer by trade, I don't get much opportunity to create from-the-ground-up web sites; usually it's tweaks, fixes, and new functionality to existing sites. And with hobby sites, I often don't find the challenges I run into with enterprise systems; usually it's starting from Visual Studio's boilerplate project and adding whatever functionality I want to play around with, rarely deploying outside my own machine. So my experience creating a new enterprise-level site was a bit dated, and the technologies to do so have come a long way, and are much more ready to go out of the box. My intention with this post isn't so much to provide any groundbreaking insights, but to just tie together a lot of information in one place to make it easy to create a new site from scratch. Architecture One site I created earlier this year had an MVC 3 front end and a WCF 4-driven service layer. Using Visual Studio 2010, these project types are easy enough to add to a new solution. I created a third Class Library project to store common functionality the front end and services layers both needed to access, for example, the DataContract classes that the front end uses to call services in the service layer. By keeping DataContract classes in a separate project, I avoided the need for the front end to have an assembly/project reference directly to the services code, a bit cleaner and more flexible of an SOA implementation. Consuming the service Even by this point, VS has given you a lot. You have a working web site and a working service, neither of which do much but are great starting points. To wire up the front end and the services, I needed to create proxy classes and WCF client configuration information. I decided to use the SvcUtil.exe utility provided as part of the Windows SDK, which you should have installed if you installed VS. VS also provides an Add Service Reference command since the .NET 1.x ASMX days, which I've never really liked; it creates several .cs/.disco/etc. files, some of which contained hardcoded URL's, adding duplicate files (*1.cs, *2.cs, etc.) without doing a good job of cleaning up after itself. I've found SvcUtil much cleaner, as it outputs one C# file (containing several proxy classes) and a config file with settings, and it's easier to use to regenerate the proxy classes when the service changes, and to then maintain all your configuration in one place (your Web.config, instead of the Service Reference files). I provided it a reference to a copy of my common assembly so it doesn't try to recreate the data contract classes, had it use the type List<T> for collections, and modified the output files' names and .NET namespace, ending up with a command like: svcutil.exe /l:cs /o:MyService.cs /config:MyService.config /r:MySite.Common.dll /ct:System.Collections.Generic.List`1 /n:*,MySite.Web.ServiceProxies http://localhost:59999/MyService.svc I took the generated MyService.cs file and drop it in the web project, under a ServiceProxies folder, matching the namespace and keeping it separate from classes I coded manually. Integrating the config file took a little more work, but only needed to be done once as these settings didn't often change. A great thing Microsoft improved with WCF 4 is configuration; namely, you can use all the default settings and not have to specify them explicitly in your config file. Unfortunately, SvcUtil doesn't generate its config file this way. If you just copy & paste MyService.config's contents into your front end's Web.config, you'll copy a lot of settings you don't need, plus this will get unwieldy if you add more services in the future, each with its own custom binding. Really, as the only mandatory settings are the endpoint's ABC's (address, binding, and contract) you can get away with just this: <system.serviceModel>  <client>    <endpoint address="http://localhost:59999/MyService.svc" binding="wsHttpBinding" contract="MySite.Web.ServiceProxies.IMyService" />  </client></system.serviceModel> By default, the services project uses basicHttpBinding. As you can see, I switched it to wsHttpBinding, a more modern standard. Using something like netTcpBinding would probably be faster and more efficient since the client & service are both written in .NET, but it requires additional server setup and open ports, whereas switching to wsHttpBinding is much simpler. From an MVC controller action method, I instantiated the client, and invoked the method for my operation. As with any object that implements IDisposable, I wrapped it in C#'s using() statement, a tidy construct that ensures Dispose gets called no matter what, even if an exception occurs. Unfortunately there are problems with that, as WCF's ClientBase<TChannel> class doesn't implement Dispose according to Microsoft's own usage guidelines. I took an approach similar to Technology Toolbox's fix, except using partial classes instead of a wrapper class to extend the SvcUtil-generated proxy, making the fix more seamless from the controller's perspective, and theoretically, less code I have to change if and when Microsoft fixes this behavior. User interface The MVC 3 project template includes jQuery and some other common JavaScript libraries by default. I updated the ones I used to the latest versions using NuGet, available in VS via the Tools > Library Package Manager > Manage NuGet Packages for Solution... > Updates. I also used this dialog to remove packages I wasn't using. Given that it's smart enough to know the difference between the .js and .min.js files, I was hoping it would be smart enough to know which to include during build and publish operations, but this doesn't seem to be the case. I ended up using Cassette to perform the minification and bundling of my JavaScript and CSS files; ASP.NET 4.5 includes this functionality out of the box. The web client to web server link via jQuery was easy enough. In my JavaScript function, unobtrusively wired up to a button's click event, I called $.ajax, corresponding to an action method that returns a JsonResult, accomplished by passing my model class to the Controller.Json() method, which jQuery helpfully translates from JSON to a JavaScript object.$.ajax calls weren't perfectly straightforward. I tried using the simpler $.post method instead, but ran into trouble without specifying the contentType parameter, which $.post doesn't have. The url parameter is simple enough, though for flexibility in how the site is deployed, I used MVC's Url.Action method to get the URL, then sent this to JavaScript in a JavaScript string variable. If the request needed input data, I used the JSON.stringify function to convert a JavaScript object with the parameters into a JSON string, which MVC then parses into strongly-typed C# parameters. I also specified "json" for dataType, and "application/json; charset=utf-8" for contentType. For success and error, I provided my success and error handling functions, though success is a bit hairier. "Success" in this context indicates whether the HTTP request succeeds, not whether what you wanted the AJAX call to do on the web server was successful. For example, if you make an AJAX call to retrieve a piece of data, the success handler will be invoked for any 200 OK response, and the error handler will be invoked for failed requests, e.g. a 404 Not Found (if the server rejected the URL you provided in the url parameter) or 500 Internal Server Error (e.g. if your C# code threw an exception that wasn't caught). If an exception was caught and handled, or if the data requested wasn't found, this would likely go through the success handler, which would need to do further examination to verify it did in fact get back the data for which it asked. I discuss this more in the next section. Logging and exception handling At this point, I had a working application. If I ran into any errors or unexpected behavior, debugging was easy enough, but of course that's not an option on public web servers. Microsoft Enterprise Library 5.0 filled this gap nicely, with its Logging and Exception Handling functionality. First I installed Enterprise Library; NuGet as outlined above is probably the best way to do so. I needed a total of three assembly references--Microsoft.Practices.EnterpriseLibrary.ExceptionHandling, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging, and Microsoft.Practices.EnterpriseLibrary.Logging. VS links with the handy Enterprise Library 5.0 Configuration Console, accessible by right-clicking your Web.config and choosing Edit Enterprise Library V5 Configuration. In this console, under Logging Settings, I set up a Rolling Flat File Trace Listener to write to log files but not let them get too large, using a Text Formatter with a simpler template than that provided by default. Logging to a different (or additional) destination is easy enough, but a flat file suited my needs. At this point, I verified it wrote as expected by calling the Microsoft.Practices.EnterpriseLibrary.Logging.Logger.Write method from my C# code. With those settings verified, I went on to wire up Exception Handling with Logging. Back in the EntLib Configuration Console, under Exception Handling, I used a LoggingExceptionHandler, setting its Logging Category to the category I already had configured in the Logging Settings. Then, from code (e.g. a controller's OnException method, or any action method's catch block), I called the Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.HandleException method, providing the exception and the exception policy name I had configured in the Exception Handling Settings. Before I got this configured correctly, when I tried it out, nothing was logged. In working with .NET, I'm used to seeing an exception if something doesn't work or isn't set up correctly, but instead working with these EntLib modules reminds me more of JavaScript (before the "use strict" v5 days)--it just does nothing and leaves you to figure out why, I presume due in part to the listener pattern Microsoft followed with the Enterprise Library. First, I verified logging worked on its own. Then, verifying/correcting where each piece wires up to the next resolved my problem. Your C# code calls into the Exception Handling module, referencing the policy you pass the HandleException method; that policy's configuration contains a LoggingExceptionHandler that references a logCategory; that logCategory should be added in the loggingConfiguration's categorySources section; that category references a listener; that listener should be added in the loggingConfiguration's listeners section, which specifies the name of the log file. One final note on error handling, as the proper way to handle WCF and MVC errors is a whole other very lengthy discussion. For AJAX calls to MVC action methods, depending on your configuration, an exception thrown here will result in ASP.NET'S Yellow Screen Of Death being sent back as a response, which is at best unnecessarily and uselessly verbose, and at worst a security risk as the internals of your application are exposed to potential hackers. I mitigated this by overriding my controller's OnException method, passing the exception off to the Exception Handling module as above. I created an ErrorModel class with as few properties as possible (e.g. an Error string), sending as little information to the client as possible, to both maximize bandwidth and mitigate risk. I then return an ErrorModel in JSON format for AJAX requests: if (filterContext.HttpContext.Request.IsAjaxRequest()){    filterContext.Result = Json(new ErrorModel(...));    filterContext.ExceptionHandled = true;} My $.ajax calls from the browser get a valid 200 OK response and go into the success handler. Before assuming everything is OK, I check if it's an ErrorModel or a model containing what I requested. If it's an ErrorModel, or null, I pass it to my error handler. If the client needs to handle different errors differently, ErrorModel can contain a flag, error code, string, etc. to differentiate, but again, sending as little information back as possible is ideal. Summary As any experienced ASP.NET developer knows, this is a far cry from where ASP.NET started when I began working with it 11 years ago. WCF services are far more powerful than ASMX ones, MVC is in many ways cleaner and certainly more unit test-friendly than Web Forms (if you don't consider the code/markup commingling you're doing again), the Enterprise Library makes error handling and logging almost entirely configuration-driven, AJAX makes a responsive UI more feasible, and jQuery makes JavaScript coding much less painful. It doesn't take much work to get a functional, maintainable, flexible application, though having it actually do something useful is a whole other matter.

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  • SQLAuthority News – Job Interviewing the Right Way (and for the Right Reasons) – Guest Post by Feodor Georgiev

    - by pinaldave
    Feodor Georgiev is a SQL Server database specialist with extensive experience of thinking both within and outside the box. He has wide experience of different systems and solutions in the fields of architecture, scalability, performance, etc. Feodor has experience with SQL Server 2000 and later versions, and is certified in SQL Server 2008. Feodor has written excellent article on Job Interviewing the Right Way. Here is his article in his own language. A while back I was thinking to start a blog post series on interviewing and employing IT personnel. At that time I had just read the ‘Smart and gets things done’ book (http://www.joelonsoftware.com/items/2007/06/05.html) and I was hyped up on some debatable topics regarding finding and employing the best people in the branch. I have no problem with hiring the best of the best; it’s just the definition of ‘the best of the best’ that makes things a bit more complicated. One of the fundamental books one can read on the topic of interviewing is the one mentioned above. If you have not read it, then you must do so; not because it contains the ultimate truth, and not because it gives the answers to most questions on the subject, but because the book contains an extensive set of questions about interviewing and employing people. Of course, a big part of these questions have different answers, depending on location, culture, available funds and so on. (What works in the US may not necessarily work in the Nordic countries or India, or it may work in a different way). The only thing that is valid regardless of any external factor is this: curiosity. In my belief there are two kinds of people – curious and not-so-curious; regardless of profession. Think about it – professional success is directly proportional to the individual’s curiosity + time of active experience in the field. (I say ‘active experience’ because vacations and any distractions do not count as experience :)  ) So, curiosity is the factor which will distinguish a good employee from the not-so-good one. But let’s shift our attention to something else for now: a few tips and tricks for successful interviews. Tip and trick #1: get your priorities straight. Your status usually dictates your priorities; for example, if the person looking for a job has just relocated to a new country, they might tend to ignore some of their priorities and overload others. In other words, setting priorities straight means to define the personal criteria by which the interview process is lead. For example, similar to the following questions can help define the criteria for someone looking for a job: How badly do I need a (any) job? Is it more important to work in a clean and quiet environment or is it important to get paid well (or both, if possible)? And so on… Furthermore, before going to the interview, the candidate should have a list of priorities, sorted by the most importance: e.g. I want a quiet environment, x amount of money, great helping boss, a desk next to a window and so on. Also it is a good idea to be prepared and know which factors can be compromised and to what extent. Tip and trick #2: the interview is a two-way street. A job candidate should not forget that the interview process is not a one-way street. What I mean by this is that while the employer is interviewing the potential candidate, the job seeker should not miss the chance to interview the employer. Usually, the employer and the candidate will meet for an interview and talk about a variety of topics. In a quality interview the candidate will be presented to key members of the team and will have the opportunity to ask them questions. By asking the right questions both parties will define their opinion about each other. For example, if the candidate talks to one of the potential bosses during the interview process and they notice that the potential manager has a hard time formulating a question, then it is up to the candidate to decide whether working with such person is a red flag for them. There are as many interview processes out there as there are companies and each one is different. Some bigger companies and corporates can afford pre-selection processes, 3 or even 4 stages of interviews, small companies usually settle with one interview. Some companies even give cognitive tests on the interview. Why not? In his book Joel suggests that a good candidate should be pampered and spoiled beyond belief with a week-long vacation in New York, fancy hotels, food and who knows what. For all I can imagine, an interview might even take place at the top of the Eifel tower (right, Mr. Joel, right?) I doubt, however, that this is the optimal way to capture the attention of a good employee. The ‘curiosity’ topic What I have learned so far in my professional experience is that opinions can be subjective. Plus, opinions on technology subjects can also be subjective. According to Joel, only hiring the best of the best is worth it. If you ask me, there is no such thing as best of the best, simply because human nature (well, aside from some physical limitations, like putting your pants on through your head :) ) has no boundaries. And why would it have boundaries? I have seen many curious and interesting people, naturally good at technology, though uninterested in it as one  can possibly be; I have also seen plenty of people interested in technology, who (in an ideal world) should have stayed far from it. At any rate, all of this sums up at the end to the ‘supply and demand’ factor. The interview process big-bang boils down to this: If there is a mutual benefit for both the employer and the potential employee to work together, then it all sorts out nicely. If there is no benefit, then it is much harder to get to a common place. Tip and trick #3: word-of-mouth is worth a thousand words Here I would just mention that the best thing a job candidate can get during the interview process is access to future team members or other employees of the new company. Nowadays the world has become quite small and everyone knows everyone. Look at LinkedIn, look at other professional networks and you will realize how small the world really is. Knowing people is a good way to become more approachable and to approach them. Tip and trick #4: Be confident. It is true that for some people confidence is as natural as breathing and others have to work hard to express it. Confidence is, however, a key factor in convincing the other side (potential employer or employee) that there is a great chance for success by working together. But it cannot get you very far if it’s not backed up by talent, curiosity and knowledge. Tip and trick #5: The right reasons What really bothers me in Sweden (and I am sure that there are similar situations in other countries) is that there is a tendency to fill quotas and to filter out candidates by criteria different from their skill and knowledge. In job ads I see quite often the phrases ‘positive thinker’, ‘team player’ and many similar hints about personality features. So my guess here is that discrimination has evolved to a new level. Let me clear up the definition of discrimination: ‘unfair treatment of a person or group on the basis of prejudice’. And prejudice is the ‘partiality that prevents objective consideration of an issue or situation’. In other words, there is not much difference whether a job candidate is filtered out by race, gender or by personality features – it is all a bad habit. And in reality, there is no proven correlation between the technology knowledge paired with skills and the personal features (gender, race, age, optimism). It is true that a significantly greater number of Darwin awards were given to men than to women, but I am sure that somewhere there is a paper or theory explaining the genetics behind this. J This topic actually brings to mind one of my favorite work related stories. A while back I was working for a big company with many teams involved in their processes. One of the teams was occupying 2 rooms – one had the team members and was full of light, colorful posters, chit-chats and giggles, whereas the other room was dark, lighted only by a single monitor with a quiet person in front of it. Later on I realized that the ‘dark room’ person was the guru and the ultimate problem-solving-brain who did not like the chats and giggles and hence was in a separate room. In reality, all severe problems which the chatty and cheerful team members could not solve and all emergencies were directed to ‘the dark room’. And thus all worked out well. The moral of the story: Personality has nothing to do with technology knowledge and skills. End of story. Summary: I’d like to stress the fact that there is no ultimately perfect candidate for a job, and there is no such thing as ‘best-of-the-best’. From my personal experience, the main criteria by which I measure people (co-workers and bosses) is the curiosity factor; I know from experience that the more curious and inventive a person is, the better chances there are for great achievements in their field. Related stories: (for extra credit) 1) Get your priorities straight. A while back as a consultant I was working for a few days at a time at different offices and for different clients, and so I was able to compare and analyze the work environments. There were two different places which I compared and recently I asked a friend of mine the following question: “Which one would you prefer as a work environment: a noisy office full of people, or a quiet office full of faulty smells because the office is rarely cleaned?” My friend was puzzled for a while, thought about it and said: “Hmm, you are talking about two different kinds of pollution… I will probably choose the second, since I can clean the workplace myself a bit…” 2) The interview is a two-way street. One time, during a job interview, I met a potential boss that had a hard time phrasing a question. At that particular time it was clear to me that I would not have liked to work under this person. According to my work religion, the properly asked question contains at least half of the answer. And if I work with someone who cannot ask a question… then I’d be doing double or triple work. At another interview, after the technical part with the team leader of the department, I was introduced to one of the team members and we were left alone for 5 minutes. I immediately jumped on the occasion and asked the blunt question: ‘What have you learned here for the past year and how do you like your job?’ The team member looked at me and said ‘Nothing really. I like playing with my cats at home, so I am out of here at 5pm and I don’t have time for much.’ I was disappointed at the time and I did not take the job offer. I wasn’t that shocked a few months later when the company went bankrupt. 3) The right reasons to take a job: personality check. A while back I was asked to serve as a job reference for a coworker. I agreed, and after some weeks I got a phone call from the company where my colleague was applying for a job. The conversation started with the manager’s question about my colleague’s personality and about their social skills. (You can probably guess what my internal reaction was… J ) So, after 30 minutes of pouring common sense into the interviewer’s head, we finally agreed on the fact that a shy or quiet personality has nothing to do with work skills and knowledge. Some years down the road my former colleague is taking the manager’s position as the manager is demoted to a different department. Reference: Feodor Georgiev, Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, Readers Contribution, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Bad performance issue on dedicated server

    - by Pierre Espenan
    I just subscribed to a dedicated server offer, and encounter some bad PHP execution performances. Actually, the time execution may be 2 times bigger than it is on my old mutualized server! I'm definitely not an expert in server management, so I'm wondering what I missed. Here are some stuff that can help you understand what's wrong here : My server (in french but easy to understand) : http://www.online.net/fr/serveur-dedie/dedibox-sc phpinfo(); output : http://jsfiddle.net/E8b7W/embedded/result/ PHP bench script (dedicated server) : http://jsfiddle.net/EhXzK/embedded/result/ PHP bench script (old mutualized) : http://jsfiddle.net/ANbWt/embedded/result/ Is it normal to get such poor performances after a kernel update and basics "apt-get install" for apache2 and php ? Thanks !

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  • Learning Linux screencasts

    - by Dmitriy Nagirnyak
    Hi, I am trying to get started with Linux. There are number of books (many of which are just man pages), some of them provide good overview so I can dig deeper online then. What I would like is to find number of screencasts that would cover basics of Linux commands, server administration, commonly performed tasks etc (no GUI, only terminal). I want to watch the screencasts to "get it quicker" and then use a book or online resources to "dig it deeper". Any recommendations? Thanks, Dmitriy.

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  • Sensei mouse sensitivity

    - by Marcelo
    I've recently acquired a Steelseries Sensei. Despite being a great mouse, I'm having some trouble finding settings that I can get used to... The mouse engine allows me to set a CPI from 0 to 5700. It also allows me to set it even higher, calling it "DCPI" (Double CPI), from 5701 to 11400. On Window's Control Panel, there's a "Pointer Speed" slider and a "Enhance Pointer Precision" checkbox (wording may be different as I use a non-english version). The majority of games allow me to set an in-game "Mouse Sensitivity". Some games let me use a "Raw mouse input". I'm already familiar with the basics of CPI/DPI - "higher CPI means less hand movement", but what are the differences between all those options? Is there a "better" or "worst" setting?

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  • Patch Management and System Inventory on a Windows network?

    - by Scott
    What are some good ways to have patch management and systems/hardware inventory for a Windows (Server 2003 or 2008) network? For example, at a minimum knowing the basics for all the machines out on the network such as OS version, patch level, what hotfixes they have, processor, ram, etc. Even better would be knowing more details such as peripherals. Ideally if there were a way to push service packs, and hotfixes (and other software?) to the machines, that would be great. What are some options for this?

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  • getting PHP PDO flavors to work on Mac OS X

    - by Jason S
    I'm running OS X 10.5; it looks like it came with Apache and PHP installed (minus some minor configurations which I turned on per this page; I've used Apache before so I know the basics of how httpd.conf works). I've got a pre-existing script which uses PDO. I've got a MySQL database and can easily configure my script to access the database via PDO MySQL or PDO ODBC. The problem is, that even though I enabled the PDO MySQL and PDO ODBC extensions in php.ini, phpinfo() reports the only PDO drivers are sqlite2 and sqlite. I'm guessing the relevant extension .dll or .so files are not present? How do I get them? note: I'm using the built-in install for PHP. (see apple's page on enabling php, which doesn't say anything about configure or adding additional .so files)

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  • Migrating from Apache2 to Lighttpd creating errors in PHP/mySQL?

    - by Jean-Philippe Murray
    Ok, I've been using basics ubuntu LAMP setups for years now, and I wanted to give lighttpd a try. My LAMP setup run in a virtual machine with scripts running just fine. So I created a new virtual machine, starting with a fresh install of ubuntu and made my setups. On this new VM, lighttpd + php works just fine. (Or at least it seems...) Problem occurs when I take the scripts from my LAMP setup and upload them to the new VM. I'm getting : Warning: mysql_real_escape_string(): Access denied for user 'www-data'@'localhost' (using password: NO) My lighttpd setup is configured as php-cgi but not my apache2 setup. Could this be the source of the problem? I think that scripts would be independent of the server configuration, so I doubt it. Also, I know that my DB connexion informations are good (as I can log in via phpmyadmin perfectly). I'm in the dark here, any pointers ? Thanks,

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  • Good place to start learning Adobe Illustrator CS5

    - by Kush
    The question may be off topic for SU, but I couldn't find any better place than this. I've been into designing for a while now, and have learned Photoshop by myself, and currently having fairly good grip in Photoshop CS5. Now due to rising needs, I need to learn Illustrator. I'm aware with the basics of Vector graphics, but haven't worked in designing such. So, suggest me a good place where I can learn Illustrator CS5, from ground up. I headed to Youtube for first start, but I still need an appropriate place where I get to learn it from better tutor. Thanks.

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  • bash one-liner loop over directories throws errors

    - by cori
    I'm trying to build a bash one-liner to loop over the directories within the current directory and tar the content into unique tars, using the directory name as the tar file name. I've got the basics working (finding the directory names, and tarring them up with those names) but my loop tosses some error messages and I can't understand where it's getting the commands its trying to run. Here's the mostly-working one-liner: for f in `ls -d */`; do `tar -czvvf ${f%/}.tar.gz $f`;done The "strange" output is: -bash: drwxrwxr-x: command not found -bash: drwxr-xr-x: command not found -bash: drwxr-xr-x: command not found -bash: drwxrwxr-x: command not found What portion of the command that I'm running do I not understand and that's generating that output?

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  • AutoHotKey - change mouse position and click a specific key every time window comes up

    - by John
    I'm a newbie to AHK, learning the basics. I'm using Notepad as an example - I want to hit the Cancel key every time I close Notepad and it asks if I want to Save/Don't Save/Cancel. I've come up with the script below and it works once but then I have to reload the script to do it again. I want it to hit Cancel every time the question box comes up. I thought Loop would work but am doing something wrong. Any ideas why, anyone? Loop IfWinExist Notepad, { WinWait Notepad WinActivate Click 312, 109 return }

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  • How to power off a hard drive to essentially "hot swap"

    - by Brandon
    I'm looking for either freeware or the programming basics to power off/on a hard drive. Mounting and unmounting a hard drive is simple enough just using the command prompt in Windows XP. Now I need to be able to power down the hard drive so it will not become damaged when being unplugged. I would prefer this to be a simple doable in the command prompt, a simple script, or at worst C++/C#. Freeware that does this exact requirement would also do the job. This script/program will run on Windows XP with .NET 2.0 SP1.

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  • Multiple URLs on one domain in IIS 6 [closed]

    - by TGnat
    Possible Duplicate: How to Host Multiple Domains / Web Sites on one IIS6 Server I'm a developer and only know the basics of IIS administration. I want to give each of my clients a personalized URL to access my web site. I have mySite.com and I would like to allow client A to acess the site via A.mySite.com and client B to use B.mySite.com. These would all point the the mySite.com domain with the same ip address. Can this be done in IIS? Do I have to register new domains for each client? Are there other ways to accomplish the same thing?

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  • What's the difference between "Flash Drive" and "Flash Memory"?

    - by Clive D
    I have a problem with a Blu ray disk I bought. I talked to a Sony technician who advised me to plug a "USB Flash Memory Stick" into the Blu-ray player. Is this something specific? Is there a difference between the following two? "USB Flash Drive" "USB Flash Memory" When I go to Curry's or other sites that sell USB Sticks, they only talk about "USB Flash Drives". I've been in computing for many years and know the basics, but "memory" and "drive" are different things to me.

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  • DNS protocol message example

    - by virtual-lab
    hello there, I am trying to figure out how to send out DNS messages from an application socket adapter to a DNSBL. I spent the last two days understanding the basics, including experimenting with WireShark to catch an example of message exchanged. Now I would like to query the DNS without using dig or host command (I'm using Ubuntu); how can I perform this action at low level, without the help of these tools in wrapping the request in a proper DNS message format? How the message should be post it? Hex or String? Thanks in advance for any help. Regards Alessandro Ilardo

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  • need recommendation for running PHP/Zend based optimizer

    - by senorsmile
    Firstly, I must admit that I don't know much about setting up PHP beyond the basics. I have an Ubuntu 10.04 server system (hosted) running primarily as an FTP store for a commercial store software. The server that the commercial store is installed on is unfortunately not very reliable, and would like to move that to this Ubuntu 10.04 server. (We've already received permission from the store vendor to do this.) My problem is that they use Zend optimizer which is only compatible with PHP 5.2. I have tried a couple of "hacks" to downgrade PHP to 5.2, but it breaks so many other things that it doesn't seem worth it. My idea is to install some sort of container of Ubuntu 8.04 (like OpenVZ) on the server to house a native install of PHP 5.2 to meet the dependency of the store software. However, it appears that OpenVZ is no longer supported on Ubuntu. Is there another solution similar that I could run on a hosted server to installed a separate "container-like" 8.04 system?

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