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  • How to safely copy an object?

    - by Prog
    This question is going to be a little long. Please bear with me. Something that happened in a project of mine made me think about how to safely copy objects. I'll present the situation I had and then ask a question. There was a class SomeClass: class SomeClass{ Thing[] things; public SomeClass(Thing[] things){ this.things = things; } // irrelevant stuff omitted public SomeClass copy(){ return new SomeClass(things); } } There was another class Processor that takes SomeClass objects, copies them (via someClassInstance.copy()), manipulates the copy's state, and returns the copy. Here it is: class Processor{ public SomeClass processObject(SomeClass object){ SomeClass copy = object.copy(); manipulateTheCopy(copy); return copy; } // irrelevant stuff omitted } I ran this, and it had bugs. I looked into these bugs, and it turned out that the manipulations Processor does on copy actually affect not only the copy, but also the original SomeClass object that was passed into processObject. I found out that it was because the original and the copy shared state - because the original passed it's field things into the copy when creating it. This made me realize that copying objects is harder than simply instantiating them with the same fields as the original. For the two objects to be completely disconnected, without any shared state, each of the fields passed to the copy also has to be copied. And if that object contains other objects - they have to be copied too. And so on. So basically, in order to be able to actually copy an object, each class in the system must have a copy() method, that also invokes copy() on all of it's fields, and so on. So for example, for copy() in SomeClass to work, it needs to look like this: public SomeClass copy(){ Thing[] copyThings = new Thing[things.length]; for(int i=0; i<things.length; i++) copyThings[i] = things[i].copy(); return new SomeClass(copyThings); } And if Thing has object fields of it's own, than it's own copy() method must be appropriate: class Thing{ Apple apple; Pencil pencil; int number; public Thing(Apple apple, Pencil pencil, int number){ this.apple = apple; this.pencil = pencil; this.number = number; } public Thing copy(){ // 'number' is a primitve. return new Thing(apple.getCopy(), pencil.getCopy(), number); } } And so on. Of course, instead of all classes having a copy() method, the copying mechanism can happen in all of the getters and the constructors of classes (unless places where it isn't suitable, for example when the field points to an external object, not to an object that 'is part' of this object). Still, that means that in order to be able to safely copy an object - most classes would have to have copying mechanisms in their getters. My question is divided into two parts: How frequently do you need to get a copy of an object? Is this a regular issue? Is the technique described common and/or reasonable? Or is there a better way to make safe copies of objects? Or is there an easier way to safely copy objects, without them sharing any state?

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  • Best approach to depth streaming via existing codec

    - by Kevin
    I'm working on a development system (and game) intended for games set mostly in static third-person views. We produce our scenery by CG and photographic techniques. Our background art is rendered off-line by a production-grade renderer. To allow the runtime imagery to properly interact with the background art, I wrote a program to convert from depth output by Mental Ray into a texture, and a pixel shader to draw a quad such that the Z data comes from the texture. This technique is working out very well, but now we've decided that some of the camera angle changes between scenes should be animated. The animation itself is straightforward to produce from our CG models. We intend to encode it to some HD video codec such as H.264. The problem is that in order to maintain our runtime imagery on the screen, the depth buffer will need to be loaded for each video frame. Due to the bandwidth, the video's depth data will need to be compressed efficiently. I've looked into methods for performing temporal compression of depth info and found an interesting research paper here: http://web4.cs.ucl.ac.uk/staff/j.kautz/publications/depth-streaming.pdf The method establishes a mapping between 16-bit depth values and YCbCr values. The mapping is tuned to the properties of existing video codecs in order to maximize precision of the decoded depths after the YCbCr has undergone video compression. It allows an existing, unmodified video codec to be used on the backend. I'm looking at how to pull this off with the least possible work. (This design change was unplanned.) Our game engine itself is native C++, presently for Win32 and DirectX, although we've worked hard to keep platform dependence segregated because we intend other ports. We don't have motion video facilities in the engine yet but will ultimately need that anyway for cinematics. I was planning on using some off-the-shelf motion video solution we can plug into our engine, and haven't chosen one yet. This new added requirement makes selecting one harder since, among other things, we'll now need to bypass colourspace conversion on one of the streams, and also will need to be playing two streams simultaneously in lockstep, on top of in some cases audio on one of them (for the cinematics). I'm also wondering if it's possible (or even useful) to do the conversion from YCbCr to depth in a pixel shader, or if it's better to just do it in CPU and separately load the resulting depth values into a locked tex. The conversion unfortunately does involve branching logic per-pixel. (There are more naive mappings that don't need branching, but they produce inferior results.) It could be reduced to a table lookup but the table would be 32MB. Programming is second-nature to me but I'm not that experienced with pix shaders and have zero knowledge of off-the-shelf video solutions. I'd therefore be interested in advice from others who may have dealt more with depth streaming, pixel shaders, and/or off-the-shelf codecs, regarding how feasible the proposed application is and what off-the-shelf video systems out there would best get along with this usage case.

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  • Texture displays on Android emulator but not on device

    - by Rob
    I have written a simple UI which takes an image (256x256) and maps it to a rectangle. This works perfectly on the emulator however on the phone the texture does not show, I see only a white rectangle. This is my code: public void onSurfaceCreated(GL10 gl, EGLConfig config) { byteBuffer = ByteBuffer.allocateDirect(shape.length * 4); byteBuffer.order(ByteOrder.nativeOrder()); vertexBuffer = byteBuffer.asFloatBuffer(); vertexBuffer.put(cardshape); vertexBuffer.position(0); byteBuffer = ByteBuffer.allocateDirect(shape.length * 4); byteBuffer.order(ByteOrder.nativeOrder()); textureBuffer = byteBuffer.asFloatBuffer(); textureBuffer.put(textureshape); textureBuffer.position(0); // Set the background color to black ( rgba ). gl.glClearColor(0.0f, 0.0f, 0.0f, 0.5f); // Enable Smooth Shading, default not really needed. gl.glShadeModel(GL10.GL_SMOOTH); // Depth buffer setup. gl.glClearDepthf(1.0f); // Enables depth testing. gl.glEnable(GL10.GL_DEPTH_TEST); // The type of depth testing to do. gl.glDepthFunc(GL10.GL_LEQUAL); // Really nice perspective calculations. gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST); gl.glEnable(GL10.GL_TEXTURE_2D); loadGLTexture(gl); } public void onDrawFrame(GL10 gl) { gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); gl.glDisable(GL10.GL_DEPTH_TEST); gl.glMatrixMode(GL10.GL_PROJECTION); // Select Projection gl.glPushMatrix(); // Push The Matrix gl.glLoadIdentity(); // Reset The Matrix gl.glOrthof(0f, 480f, 0f, 800f, -1f, 1f); gl.glMatrixMode(GL10.GL_MODELVIEW); // Select Modelview Matrix gl.glPushMatrix(); // Push The Matrix gl.glLoadIdentity(); // Reset The Matrix gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glLoadIdentity(); gl.glTranslatef(card.x, card.y, 0.0f); gl.glBindTexture(GL10.GL_TEXTURE_2D, texture[0]); //activates texture to be used now gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vertexBuffer); gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer); gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); } public void onSurfaceChanged(GL10 gl, int width, int height) { // Sets the current view port to the new size. gl.glViewport(0, 0, width, height); // Select the projection matrix gl.glMatrixMode(GL10.GL_PROJECTION); // Reset the projection matrix gl.glLoadIdentity(); // Calculate the aspect ratio of the window GLU.gluPerspective(gl, 45.0f, (float) width / (float) height, 0.1f, 100.0f); // Select the modelview matrix gl.glMatrixMode(GL10.GL_MODELVIEW); // Reset the modelview matrix gl.glLoadIdentity(); } public int[] texture = new int[1]; public void loadGLTexture(GL10 gl) { // loading texture Bitmap bitmap; bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.image); // generate one texture pointer gl.glGenTextures(0, texture, 0); //adds texture id to texture array // ...and bind it to our array gl.glBindTexture(GL10.GL_TEXTURE_2D, texture[0]); //activates texture to be used now // create nearest filtered texture gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR); // Use Android GLUtils to specify a two-dimensional texture image from our bitmap GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0); // Clean up bitmap.recycle(); } As per many other similar issues and resolutions on the web i have tried setting the minsdkversion is 3, loading the bitmap via an input stream bitmap = BitmapFactory.decodeStream(is), setting BitmapFactory.Options.inScaled to false, putting the images in the nodpi folder and putting them in the raw folder.. all of which didn't help. I'm not really sure what else to try..

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  • SQL to select random mix of rows fairly [migrated]

    - by Matt Sieker
    Here's my problem: I have a set of tables in a database populated with data from a client that contains product information. In addition to the basic product information, there is also information about the manufacturer, and categories for those products (a product can be in one or more categories). These categories are then referred to as "Product Categories", and which stores these products are available at. These tables are updated once a week from a feed from the customer. Since for our purposes, some of the product categories are the same, or closely related for our purposes, there is another level of categories called "General Categories", a general category can have one or more product categories. For the scope of these tables, here's some rough numbers: Data Tables: Products: 475,000 Manufacturers: 1300 Stores: 150 General Categories: 245 Product Categories: 500 Mapping Tables: Product Category -> Product: 655,000 Stores -> Products: 50,000,000 Now, for the actual problem: As part of our software, we need to select n random products, given a store and a general category. However, we also need to ensure a good mix of manufacturers, as in some categories, a single manufacturer dominates the results, and selecting rows at random causes the results to strongly favor that manufacturer. The solution that is currently in place, works for most cases, involves selecting all of the rows that match the store and category criteria, partition them on manufacturer, and include their row number from within their partition, then select from that where the row number for that manufacturer is less than n, and use ROWCOUNT to clamp the total rows returned to n. This query looks something like this: SET ROWCOUNT 6 select p.Id, GeneralCategory_Id, Product_Id, ISNULL(m.DisplayName, m.Name) AS Vendor, MSRP, MemberPrice, FamilyImageName from (select p.Id, gc.Id GeneralCategory_Id, p.Id Product_Id, ctp.Store_id, Manufacturer_id, ROW_NUMBER() OVER (PARTITION BY Manufacturer_id ORDER BY NEWID()) AS 'VendorOrder', MSRP, MemberPrice, FamilyImageName from GeneralCategory gc inner join GeneralCategoriesToProductCategories gctpc ON gc.Id=gctpc.GeneralCategory_Id inner join ProductCategoryToProduct pctp on gctpc.ProductCategory_Id = pctp.ProductCategory_Id inner join Product p on p.Id = pctp.Product_Id inner join StoreToProduct ctp on p.Id = ctp.Product_id where gc.Id = @GeneralCategory and ctp.Store_id=@StoreId and p.Active=1 and p.MemberPrice >0) p inner join Manufacturer m on m.Id = p.Manufacturer_id where VendorOrder <=6 order by NEWID() SET ROWCOUNT 0 (I've tried to somewhat format it to make it cleaner, but I don't think it really helps) Running this query with an execution plan shows that for the majority of these tables, it's doing a Clustered Index Seek. There are two operations that take up roughly 90% of the time: Index Seek (Nonclustered) on StoreToProduct: 17%. This table just contains the key of the store, and the key of the product. It seems that NHibernate decided not to make a composite key when making this table, but I'm not concerned about this at this point, as compared to the other seek... Clustered Index Seek on Product: 69%. I really have no clue how I could make this one more performant. On categories without a lot of products, performance is acceptable (<50ms), however larger categories can take a few hundred ms, with the largest category taking 3s (which has about 170k products). It seems I have two ways to go from this point: Somehow optimize the existing query and table indices to lower the query time. As almost every expensive operation is already a clustered index scan, I don't know what could be done there. The inner query could be tuned to not return all of the possible rows for that category, but I am unsure how to do this, and maintain the requirements (random products, with a good mix of manufacturers) Denormalize this data for the purpose of this query when doing the once a week import. However, I am unsure how to do this and maintain the requirements. Does anyone have any input on either of these items?

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  • Consumer Oriented Search In Oracle Endeca Information Discovery - Part 2

    - by Bob Zurek
    As discussed in my last blog posting on this topic, Information Discovery, a core capability of the Oracle Endeca Information Discovery solution enables businesses to search, discover and navigate through a wide variety of big data including structured, unstructured and semi-structured data. With search as a core advanced capabilities of our product it is important to understand some of the key differences and capabilities in the underlying data store of Oracle Endeca Information Discovery and that is our Endeca Server. In the last post on this subject, we talked about Exploratory Search capabilities along with support for cascading relevance. Additional search capabilities in the Endeca Server, which differentiate from simple keyword based "search boxes" in other Information Discovery products also include: The Endeca Server Supports Set Search.  The Endeca Server is organized around set retrieval, which means that it looks at groups of results (all the documents that match a search), as well as the relationship of each individual result to the set. Other approaches only compute the relevance of a document by comparing the document to the search query – not by comparing the document to all the others. For example, a search for “U.S.” in another approach might match to the title of a document and get a high ranking. But what if it were a collection of government documents in which “U.S.” appeared in many titles, making that clue less meaningful? A set analysis would reveal this and be used to adjust relevance accordingly. The Endeca Server Supports Second-Order Relvance. Unlike simple search interfaces in traditional BI tools, which provide limited relevance ranking, such as a list of results based on key word matching, Endeca enables users to determine the most salient terms to divide up the result. Determining this second-order relevance is the key to providing effective guidance. Support for Queries and Filters. Search is the most common query type, but hardly complete, and users need to express a wide range of queries. Oracle Endeca Information Discovery also includes navigation, interactive visualizations, analytics, range filters, geospatial filters, and other query types that are more commonly associated with BI tools. Unlike other approaches, these queries operate across structured, semi-structured and unstructured content stored in the Endeca Server. Furthermore, this set is easily extensible because the core engine allows for pluggable features to be added. Like a search engine, queries are answered with a results list, ranked to put the most likely matches first. Unlike “black box” relevance solutions, which generalize one strategy for everyone, we believe that optimal relevance strategies vary across domains. Therefore, it provides line-of-business owners with a set of relevance modules that let them tune the best results based on their content. The Endeca Server query result sets are summarized, which gives users guidance on how to refine and explore further. Summaries include Guided Navigation® (a form of faceted search), maps, charts, graphs, tag clouds, concept clusters, and clarification dialogs. Users don’t explicitly ask for these summaries; Oracle Endeca Information Discovery analytic applications provide the right ones, based on configurable controls and rules. For example, the analytic application might guide a procurement agent filtering for in-stock parts by visualizing the results on a map and calculating their average fulfillment time. Furthermore, the user can interact with summaries and filters without resorting to writing complex SQL queries. The user can simply just click to add filters. Within Oracle Endeca Information Discovery, all parts of the summaries are clickable and searchable. We are living in a search driven society where business users really seem to enjoy entering information into a search box. We do this everyday as consumers and therefore, we have gotten used to looking for that box. However, the key to getting the right results is to guide that user in a way that provides additional Discovery, beyond what they may have anticipated. This is why these important and advanced features of search inside the Endeca Server have been so important. They have helped to guide our great customers to success. 

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  • WF4 &ndash; Guess the number game!

    - by MarkPearl
    I posted yesterday how really good WF4 was looking. Today I thought I would show some real basics that I was able to figure out. This will be a simple example, I am going to make a flowchart workflow – which will prompt the user to guess the number until they guess the right number. Lets begin… Make a new project and make it a Workflow console Application. Then select the Workflow file and drag a FlowChart (2) to point 3. This will now show a green start circle in the designer form. We are going to work with primitives to start with. We are now going to drag a few objects onto the Workflow, We drag the WriteLine, Assign & Decision items onto the designer. Once they are dragged onto the designer we will want to link them up. The order that they are linked is critical since this will determine the order of the solution. In this case, we want the system to first ask “Guess a number”, then to wait for the user to input some code, and then to display “You got it” if they got it right, and “Try again” if they got it wrong. So we now link the arrows to the objects. This is done by moving the mouse pointer over the start objects and clicking on one of the toggles and then dragging it to the next object and releasing the button over one of the toggles. This will place an arrow from the source object to the target object. Okay… pretty simple stuff – now we just need these primitive objects to do stuff. Lets start with the WriteLine primitive. We place the text in inverted commas in the Text field. Because this field accepts any valid VB expression we could have put variables etc. in there if we wanted to. The next thing we want to do is allow the user to input a number. This brings up an interesting problem, if a user were to type in a number, there would need to be someway to declare a variable to hold that value for the life of the workflow. We can achieve this by declaring a variable. To declare a variable, move your cursor over the variables tab at the bottom of the workflow, and then type the name of the new variable in the “Create Variable” field and set it as shown in the image above. Now that we have a variable, we want to call the Console.Readline method and assign the inputted value from the Console to that variable. The code that cannot be seen is actually this – Convert.ToInt32(Console.ReadLine()) We now have a workflow that first prompts the user for a number, then allows the user to type in a number. We are almost done, we just need to make the system react to the value inputted. There are a few ways we could do this, I am going to use the Decision item. So select the Decision object on the designer and then view its properties (F4 for me), and in the condition field place a condition. For simplicity sake I have decided that if the user guesses 10, they will have guessed the number. This is now the completed workflow. Its really easy to understand and shows some really powerful principles for Business applications. You can run the application and see what it does. Imagine writing business solutions that do not worry about the exact flow of objects, but simply allows a business analyst or someone to configure the solution to work exactly as the business rules would dictate. And if the rules changed six months later all they would need to do is re-drag some of the flows. Now I do not know if WF4 will allow for this, but it feels like it is a step in the right direct.

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  • My architecture has a problem with views that required information from different objects. How can I solve this?

    - by Oscar
    I am building an architecture like this: These are my SW layers ______________ | | | Views | |______________| ______________ | | |Business Logic| |______________| ______________ | | | Repository | |______________| My views are going to generate my HTML to be sent to the user Business logic is where all the business logics are Repository is a layer to access the DB My idea is that the repository uses entities (that are basically the representation of the tables, in order to perform DB queries. The layers communicate between themselves using Business Objects, that are objects that represent the real-world-object itself. They can contain business rules and methods. The views build/use DTOs, they are basically objects that have the information required to be shown on the screen. They expect also this kind of object on actions and, before calling the business logic, they create BO. First question: what is your overall feeling about this architecture? I've used similar architecture for some projects and I always got this problem: If my view has this list to show : Student1, age, course, Date Enrolled, Already paid? It has information from different BO. How do you think one should build the structure? These were the alternatives I could think of: The view layer could call the methods to get the student, then the course it studies, then the payment information. This would cause a lot of DB accesses and my view would have the knowledge about how to act to generate this information. This just seems wrong for me. I could have an "adapter object", that has the required information (a class that would have a properties Student, Course and Payment). But I would required one adapter object for each similar case, this may get very bad for big projects. I still don't like them. Would you have ideas? How would you change the architecture to avoid this kind of problems? @Rory: I read the CQRS and I don't think this suits my needs. As taken from a link references in your link Before describing the details of CQRS we need to understand the two main driving forces behind it: collaboration and staleness That means: many different actors using the same object (collaboration) and once data has been shown to a user, that same data may have been changed by another actor – it is stale (staleness). My problem is that I want to show to the user information from different BO, so I would need to receive them from the service layer. How can my service layer assemble and deliver this information? Edit to @AndrewM: Yes, you understood it correctly, the original idea was to have the view layer to build the BOs, but you have a very nice point about the creation of the BO inside the business layers. Assuming I follow your advice and move the creation logic inside the business layer, my business layer interface would contain the DTOs, for instance public void foo(MyDTO object) But as far as I understand, the DTO is tightly coupled to each view, so it would not be reusable by a second view. In order to use it, the second view would need to build a specific DTO from a specific view or I would have to duplicate the code in the business layer. Is this correct or am I missing something?

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  • Proving What You are Worth

    - by Ted Henson
    Here is a challenge for everyone. Just about everyone has been asked to provide or calculate the Return on Investment (ROI), so I will assume everyone has a method they use. The problem with stopping once you have an ROI is that those in the C-Suite probably do not care about the ROI as much as Return on Equity (ROE). Shareholders are mostly concerned with their return on the money the invested. Warren Buffett looks at ROE when deciding whether to make a deal or not. This article will outline how you can add more meaning to your ROI and show how you can potentially enhance the ROE of the company.   First I want to start with a base definition I am using for ROI and ROE. Return on investment (ROI) and return on equity (ROE) are ways to measure management effectiveness, parts of a system of measures that also includes profit margins for profitability, price-to-earnings ratio for valuation, and various debt-to-equity ratios for financial strength. Without a set of evaluation metrics, a company's financial performance cannot be fully examined by investors. ROI and ROE calculate the rate of return on a specific investment and the equity capital respectively, assessing how efficient financial resources have been used. Typically, the best way to improve financial efficiency is to reduce production cost, so that will be the focus. Now that the challenge has been made and items have been defined, let’s go deeper. Most research about implementation stops short at system start-up and seldom addresses post-implementation issues. However, we know implementation is a continuous improvement effort, and continued efforts after system start-up will influence the ultimate success of a system.   Most UPK ROI’s I have seen only include the cost savings in developing the training material. Some will also include savings based on reduced Help Desk calls. Using just those values you get a good ROI. To get an ROE you need to go a little deeper. Typically, the best way to improve financial efficiency is to reduce production cost, which is the purpose of implementing/upgrading an enterprise application. Let’s assume the new system is up and running and all users have been properly trained and are comfortable using the system. You provide senior management with your ROI that justifies the original cost. What you want to do now is develop a good base value to a measure the current efficiency. Using usage tracking you can look for various patterns. For example, you may find that users that are accessing UPK assistance are processing a procedure, such as entering an order, 5 minutes faster than those that don’t.  You do some research and discover each minute saved in processing a claim saves the company one dollar. That translates to the company saving five dollars on every transaction. Assuming 100,000 transactions are performed a year, and all users improve their performance, the company will be saving $500,000 a year. That $500,000 can be re-invested, used to reduce debt or paid to the shareholders.   With continued refinement during the life cycle, you should be able to find ways to reduce cost. These are the type of numbers and productivity gains that senior management and shareholders want to see. Being able to quantify savings and increase productivity may also help when seeking a raise or promotion.

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  • HERMES Medical Solutions Helps Save Lives with MySQL

    - by Bertrand Matthelié
    Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Cambria","serif"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} HERMES Medical Solutions was established in 1976 in Stockholm, Sweden, and is a leading innovator in medical imaging hardware/software products for health care facilities worldwide. HERMES delivers a plethora of different medical imaging solutions to optimize hospital workflow. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Cambria","serif"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} HERMES advanced algorithms make it possible to detect the smallest changes under therapies important and necessary to optimize different therapeutic methods and doses. Challenges Fighting illness & disease requires state-of-the-art imaging modalities and software in order to diagnose accurately, stage disease appropriately and select the best treatment available. Selecting and implementing a new database platform that would deliver the needed performance, reliability, security and flexibility required by the high-end medical solutions offered by HERMES. Solution Decision to migrate from in-house database to an embedded SQL database powering the HERMES products, delivered either as software, integrated hardware and software solutions, or via the cloud in a software-as-a-service configuration. Evaluation of several databases and selection of MySQL based on its high performance, ease of use and integration, and low Total Cost of Ownership. On average, between 4 and 12 Terabytes of data are stored in MySQL databases underpinning the HERMES solutions. The data generated by each medical study is indeed stored during 10 years or more after the treatment was performed. MySQL-based HERMES systems also allow doctors worldwide to conduct new drug research projects leveraging the large amount of medical data collected. Hospitals and other HERMES customers worldwide highly value the “zero administration” capabilities and reliability of MySQL, enabling them to perform medical analysis without any downtime. Relying on MySQL as their embedded database, the HERMES team has been able to increase their focus on further developing their clinical applications. HERMES Medical Solutions could leverage the Oracle Financing payment plan to spread its investment over time and make the MySQL choice even more valuable. “MySQL has proven to be an excellent database choice for us. We offer high-end medical solutions, and MySQL delivers the reliability, security and performance such solutions require.” Jan Bertling, CEO.

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  • Collaborative Organizations build Organizational Culture

    “A Collaborative organization builds its culture based on the idea of the family or an athletic team.”(Hoefling, 2001) As I grew up, I participated in many different types of clubs, civic organizations, and sports teams.  Now looking back at the more successful undertakings, I can see three commonalities amongst them. They all shared a defined purpose or goal, defined functional roles, and a shared sense of responsibility to the group. Defined Purpose or Goal In order to unit people to work together, they must share a common goal or have a common purpose. An example of this would be the Lions Club International Foundation. There purpose is to help everyone to lead healthier and more productive lives, nurtures the potential of youth, promotes health, serves the elderly, empowers the disabled and helps victims of disasters. This organization holds localized meetings across the world and works in conjunction with other localized clubs within there organization along with other organizations to promote common goals. If there are no common goals for the group, then there is nothing that binds people to the group, and nothing will be done. Defined Functional Roles In order for an organization to work and function as a team, they must have defined roles and everyone must know how their roles are interdependent on each other. Lets shed light on this subject by looking at a football team’s offense.  Each player has an assigned role to play each time the ball is snapped. The offensive line blocks for the running back or quarterback, the quarterback passes the ball to the wide receiver or hands it off to the running back and the running back and wide receivers run with the ball towards the goal line. Each member of this team shares a common goal of scoring a touchdown, but if each team member does not fulfill their assigned roles the offences will collapse and the team will lose yards. This will provide a set back to the teams goal of scoring a touchdown because they potential are then farther away from the goal line.  In addition, if all the players do not know their roles and how they are part of a larger team then even larger yard losses can occur. Shared Sense of Personal Responsibility to the Group Shared responsibility comes with the shared common goals. Each person in the organization must do their part to promote the common shared goal or purpose based on their abilities. A prime example of this is a wrestling team competing in a match. Points are awarded to the team based on how many wins the team achieves in the meet and of that how many wins where won by decision or by pin. If a wrestler pins his opponent the teams will receive 2 points for the win, but if the wrestler wins by decision, then the team only gets one point for the win. So it is the responsibility of each person on the team to not get pinned if they are unable to win the match. If the team member gets pinned then the other team receives an additional point for the win. References: Hoefling, T. (2001). Working Virtually: Managing People for Successful Virtual Teams and Organizations. Sterling, VA: Stylus Publishing, LLC.

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  • Cream of the Crop

    - by KemButller
    JD Edwards has been working hard to ensure that you shouldn't have to work so hard! Yet there are still JD Edwards customers that may not be up to speed on all the new and or improved tools and utilities we have delivered, all designed to make your life easier. So today, I want to share what I consider to be the cream of the crop….those items that every customer should know about and leverage to make ERP life just a little bit (or A LOT) easier! These are my top picks, the cream of a very good crop! Explore and enjoy, and gain some of your time back to do with as you please. · www.runjde.com It’s where to go when you need to know! The Resource Kits available on www.runjde.com provide comprehensive Resource Kits (guides) by user type. The guides provide brief descriptions of the wide array of resources that are available to JD Edwards’s eco system and links to each of those resources. · My Oracle Support (MOS) Information Centers This link will take you to an index that is designed to provide you with simple and quick navigation to the available EnterpriseOne Information Centers. This index provides links to: · EnterpriseOne Application specific Information Centers · EnterpriseOne Tools and Technology Information Centers · EnterpriseOne Performance Information Center · EnterpriseOne 9.1 and 9.0 Information Centers Information Centers give Oracle the ability to aggregate content for a given focus area and present this content in categories for easy browsing by our customers. Information Centers offer a variety of focused dynamic content organized around one or more of the following tasks. · Overview · Use · Troubleshooting · Patching and Maintenance · Install and Configure · Upgrade · Optimize Performance · Security · Certify JD Edwards Newsletters Be in the know by reading the Global Customer Support Product Newsletters. They are PACKED with news and information covering a wide range of topics and news. It is a must read if you want to know what’s happening in the JD Edwards universe! Read the latest EntepriseOne newsletter Read the latest World newsletter Learn How to receive notification when a new newsletter edition is published Oracle Learning Library – (OLL) Oracle Learn Library is the place to go for easy access to JD Edwards Application and Tools training. For a comprehensive view of the training available for a specific product/functional area, explore the Knowledge Paths For Net Change (new feature) training, explore the TOI sessions (TOI stands for Transfer Of Information). Tip: Be sure to experiment with the search filters! · www.upgradejde.com The site designed to help customers and partners with the process of upgrading JD Edwards. The site is a wealth of information, tools and resources designed to assist in the evaluation, planning and execution steps required when upgrading. Of note is the wildly successful upgrade strategy known as “The Art of the Possible” wherein JD Edwards and many of our partners hold free workshops to teach customers how to conduct upgrades in 100 days or less. Equally important is the fact that on www.upgradejde.com, customers can gain visibility into planned enhancements using the Product and Technology Feature Catalogs. The catalogs are great for creating customer specific reports about the net change between older releases and current or planned releases. Examples of other key resources on www.upgradejde.com are the product data base changes between releases, extensibility guides, (formerly known as programmer’s guides), whitepapers, ROI calculators and much more!

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  • How do you deal with poor management [closed]

    - by Sybiam
    I come from a company where during a project, we saw the client 3 time during the whole project. We were never informed when did the client came in office in order to discuss with him about his requirements. I did setup redmine and told them that if they have any request they can post an issue there. But they never really used redmine to publish anything. They would instead: harass a team member on the phone at any time of the day or night hand us over sheets of paper with new requests or changes hand us over new design (graphical) They requested how much time it would take us to finish the project, I gave them a date and a week to test everything and deployment. I calculated that time taking into account the current features we had to do. And then blamed us that our deadline was wrong and that we lied. But the truth is that one week before that deadline they added a couple of monster feature from nowhere and that week were we were supposed to test and deploy, my friends spent all day in the office changing all little things. After that project, my friend got some kind of depression and got scared everytime his phone rang. They kind of used him as a communication proxy. After that project of hell, (every body got pissed off on that project) as far as I know the designer who was working with us left work after that project and she had some kind of issue too with managers. My team also started looking for work somewhere else. At first I tried to get things straight with management, I tried to make a meeting to discuss about the communication issues and so on.. What really pissed me off and made me leave that job for good is the following. Me: "We have to discuss about what went wrong on the last project. It's quite important" Him: "Lets talk about it in a week or two. Just make a list of all the things you did wrong" Me: "We already have a new project and we want to prevent what happened on the last project to happen again" Him: "Just do it and well have our meeting in a week, make a list of all the thing you did wrong." It kind of ended there then he organized a meeting at a moment I wasn't unable to come. My friend discussed with him and tried to explained him that we really had to discuss about organization issue on how to manage a project. And his answer was pretty much: "During the meeting I don't want to ear how you want to us to manage a project but I want to know what you guys did wrong" After that I felt it wasn't even worth it discussing anything since they weren't even ready listening to us. Found a new job and I'm pretty happy with my choice. I'd like to know how you'd handle such situation. Is there anything to do to solve communication problem? After that project my friend got a depression and some other employee had their down too as far as I know. I wonder what else we can do other than leave these place as soon as possible. Feel sad for the people that are still there and get screamed at just because they need money in order to eat and finding an other job like that isn't that easy. note I died a little when our boss asked us to make a list of things we (programmers) did wrong. This is probably the stupidest request I ever got. If everybody thinks they did everything right, it doesn't mean that there is no problems. Individual problem are rarely the big issue. Colleagues help each others and solve theses issues to prevent problems.

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  • Creating a voxel world with 3D arrays using threads

    - by Sean M.
    I am making a voxel game (a bit like Minecraft) in C++(11), and I've come across an issue with creating a world efficiently. In my program, I have a World class, which holds a 3D array of Region class pointers. When I initialize the world, I give it a width, height, and depth so it knows how large of a world to create. Each Region is split up into a 32x32x32 area of blocks, so as you may guess, it takes a while to initialize the world once the world gets to be above 8x4x8 Regions. In order to alleviate this issue, I thought that using threads to generate different levels of the world concurrently would make it go faster. Having not used threads much before this, and being still relatively new to C++, I'm not entirely sure how to go about implementing one thread per level (level being a xz plane with a height of 1), when there is a variable number of levels. I tried this: for(int i = 0; i < height; i++) { std::thread th(std::bind(&World::load, this, width, height, depth)); th.join(); } Where load() just loads all Regions at height "height". But that executes the threads one at a time (which makes sense, looking back), and that of course takes as long as generating all Regions in one loop. I then tried: std::thread t1(std::bind(&World::load, this, w, h1, h2 - 1, d)); std::thread t2(std::bind(&World::load, this, w, h2, h3 - 1, d)); std::thread t3(std::bind(&World::load, this, w, h3, h4 - 1, d)); std::thread t4(std::bind(&World::load, this, w, h4, h - 1, d)); t1.join(); t2.join(); t3.join(); t4.join(); This works in that the world loads about 3-3.5 times faster, but this forces the height to be a multiple of 4, and it also gives the same exact VAO object to every single Region, which need individual VAOs in order to render properly. The VAO of each Region is set in the constructor, so I'm assuming that somehow the VAO number is not thread safe or something (again, unfamiliar with threads). So basically, my question is two one-part: How to I implement a variable number of threads that all execute at the same time, and force the main thread to wait for them using join() without stopping the other threads? How do I make the VAO objects thread safe, so when a bunch of Regions are being created at the same time across multiple threads, they don't all get the exact same VAO? Turns out it has to do with GL contexts not working across multiple threads. I moved the VAO/VBO creation back to the main thread. Fixed! Here is the code for block.h/.cpp, region.h/.cpp, and CVBObject.h/.cpp which controls VBOs and VAOs, in case you need it. If you need to see anything else just ask. EDIT: Also, I'd prefer not to have answers that are like "you should have used boost". I'm trying to do this without boost to get used to threads before moving onto other libraries.

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  • Admin Panel like Custom Framework

    - by bhuvin
    I want to Create a Framework , like Admin panel , which can rule almost all the aspects of what is shown on the frontend. For an (most basic) example: If suppose the links which are to be shown in a navigation area is passed from the server, with the order and the url , etc. The whole aim is to save the time on the tedious tasks. You can just start creating menus and start assigning pages to it. Give a url, actual files which are to be rendered (in case of static files.), in case of dynamic files, giving the file accordingly. And all this is fully server side manageable using different portlets, sort of things. So basic Roadmap is having : Areas like: Header Area - Which can contain logos, links etc. Navigation Area - Which can contains links and submenus. Content Area - Now this is where the tricky part is that that it has zones like: left, center & right. It contains Order in which it has to be displayed. So, when someday we want to change the way the articles appear on the page, we can do so easily, without any deployments. Now these zones can have n number of internal elements, like the word cloud, or the advertisement area. Footer Area: Again similar as Header Area. Currently there is a preexisting custom framework, which uses XSLT files for pulling out data from the server side. And it has the above capabilities. For example: If there's a grid it will be having a <table> tag embedded in the XSLT file. Now whatever might be the source of the data, we serialize this as XML and give it to the XSLT file and the html is derived from this and is appended to the layer in a page. The problem with this approach is: The XSLT conversion is occurring on the server side, so the server is responsible for getting the data, running XSLT transform, and append the html generated to the layer div. So, according to me, firstly this isn't the server's concern to do so. Secondly for larger applications this might be slower. Debugging isn't possible for XSLT transformation. So, whenever we face problems with data its always a bit of a trial & error method. Maintaining it is a bit of an eerie job i.e. styling changes, and other stuff. Adding dynamic values. Like JavaScript can't actually be very easily used in this. Secondly, we can't use JQuery or any other libraries with this since this is all occurring on the server. For now what I have thought about is using Templating - Javascript - JSON combination in place of XSLT, this will be offloaded to the client and the rendering will take place accordingly. This could solve the above problems and also could add mobile support for the same. Only problem which I could think of is that: It is much work and adding new portlets on the go needs to be looked into. What could be the alternatives for this? What kind of problems are there with the JavaScript approach? What are the different ways to implement the same? Are there any existing frameworks for similar usage?

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  • Getting Started with Cloud Computing

    - by juanlarios
    You’ve likely heard about how Office 365 and Windows Intune are great applications to get you started with Cloud Computing. Many of you emailed me asking for more info on what Cloud Computing is, including the distinction between "Public Cloud" and "Private Cloud". I want to address these questions and help you get started. Let's begin with a brief set of definitions and some places to find more info; however, an excellent place where you can always learn more about Cloud Computing is the Microsoft Virtual Academy. Public Cloud computing means that the infrastructure to run and manage the applications users are taking advantage of is run by someone else and not you. In other words, you do not buy the hardware or software to run your email or other services being used in your organization – that is done by someone else. Users simply connect to these services from their computers and you pay a monthly subscription fee for each user that is taking advantage of the service. Examples of Public Cloud services include Office 365, Windows Intune, Microsoft Dynamics CRM Online, Hotmail, and others. Private Cloud computing generally means that the hardware and software to run services used by your organization is run on your premises, with the ability for business groups to self-provision the services they need based on rules established by the IT department. Generally, Private Cloud implementations today are found in larger organizations but they are also viable for small and medium-sized businesses since they generally allow an automation of services and reduction in IT workloads when properly implemented. Having the right management tools, like System Center 2012, to implement and operate Private Cloud is important in order to be successful. So – how do you get started? The first step is to determine what makes the most sense to your organization. The nice thing is that you do not need to pick Public or Private Cloud – you can use elements of both where it makes sense for your business – the choice is yours. When you are ready to try and purchase Public Cloud technologies, the Microsoft Volume Licensing web site is a good place to find links to each of the online services. In particular, if you are interested in a trial for each service, you can visit the following pages: Office 365, CRM Online, Windows Intune, and Windows Azure. For Private Cloud technologies, start with some of the courses on Microsoft Virtual Academy and then download and install the Microsoft Private Cloud technologies including Windows Server 2008 R2 Hyper-V and System Center 2012 in your own environment and take it for a spin. Also, keep up to date with the Canadian IT Pro blog to learn about events Microsoft is delivering such as the IT Virtualization Boot Camps and more to get you started with these technologies hands on. Finally, I want to ask for your help to allow the team at Microsoft to continue to provide you what you need. Twice a year through something we call "The Global Relationship Study" – they reach out and contact you to see how they're doing and what Microsoft could do better. If you get an email from "Microsoft Feedback" with the subject line "Help Microsoft Focus on Customers and Partners" between March 5th and April 13th, please take a little time to tell them what you think. Cloud Computing Resources: Microsoft Server and Cloud Computing site – information on Microsoft's overall cloud strategy and products. Microsoft Virtual Academy – for free online training to help improve your IT skillset. Office 365 Trial/Info page – get more information or try it out for yourself. Office 365 Videos – see how businesses like yours have used Office 365 to transition to the cloud. Windows Intune Trial/Info – get more information or try it out for yourself. Microsoft Dynamics CRM Online page – information on trying and licensing Microsoft Dynamics CRM Online. Additional Resources You May Find Useful: Springboard Series Your destination for technical resources, free tools and expert guidance to ease the deployment and management of your Windows-based client infrastructure. TechNet Evaluation Center Try some of our latest Microsoft products for free, Like System Center 2012 Pre-Release Products, and evaluate them before you buy. AlignIT Manager Tech Talk Series A monthly streamed video series with a range of topics for both infrastructure and development managers. Ask questions and participate real-time or watch the on-demand recording. Tech·Days Online Discover what's next in technology and innovation with Tech·Days session recordings, hands-on labs and Tech·Days TV.

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  • Why is x=x++ undefined?

    - by ugoren
    It's undefined because the it modifies x twice between sequence points. The standard says it's undefined, therefore it's undefined. That much I know. But why? My understanding is that forbidding this allows compilers to optimize better. This could have made sense when C was invented, but now seems like a weak argument. If we were to reinvent C today, would we do it this way, or can it be done better? Or maybe there's a deeper problem, that makes it hard to define consistent rules for such expressions, so it's best to forbid them? So suppose we were to reinvent C today. I'd like to suggest simple rules for expressions such as x=x++, which seem to me to work better than the existing rules. I'd like to get your opinion on the suggested rules compared to the existing ones, or other suggestions. Suggested Rules: Between sequence points, order of evaluation is unspecified. Side effects take place immediately. There's no undefined behavior involved. Expressions evaluate to this value or that, but surely won't format your hard disk (strangely, I've never seen an implementation where x=x++ formats the hard disk). Example Expressions x=x++ - Well defined, doesn't change x. First, x is incremented (immediately when x++ is evaluated), then it's old value is stored in x. x++ + ++x - Increments x twice, evaluates to 2*x+2. Though either side may be evaluated first, the result is either x + (x+2) (left side first) or (x+1) + (x+1) (right side first). x = x + (x=3) - Unspecified, x set to either x+3 or 6. If the right side is evaluated first, it's x+3. It's also possible that x=3 is evaluated first, so it's 3+3. In either case, the x=3 assignment happens immediately when x=3 is evaluated, so the value stored is overwritten by the other assignment. x+=(x=3) - Well defined, sets x to 6. You could argue that this is just shorthand for the expression above. But I'd say that += must be executed after x=3, and not in two parts (read x, evaluate x=3, add and store new value). What's the Advantage? Some comments raised this good point. It's not that I'm after the pleasure of using x=x++ in my code. It's a strange and misleading expression. What I want is to be able to understand complicated expressions. Normally, a complicated expression is no more than the sum of its parts. If you understand the parts and the operators combining them, you can understand the whole. C's current behavior seems to deviate from this principle. One assignment plus another assignment suddenly doesn't make two assignments. Today, when I look at x=x++, I can't say what it does. With my suggested rules, I can, by simply examining its components and their relations.

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  • How can I work efficiently on a desktop sharing workflow?

    - by OSdave
    I am a freelance Magento developer, based in Spain. One of my clients is a Germany based web development company and they're asking me something I think it's impossible. OK, maybe not impossible but definitely not a preferred way of doing things. One of their clients has a Magento Entreprise installation, which is the paid (and I think proprietary) version of Magento. Their client has forbidden them to download the files from his server. My client is asking me now to study one particular module of the application in order to interact with it from a custom module I'll have to develop. As they have a read-only ssh access to their client's server, they came up with this solution: Set up a desktop/screen sharing session between one of their developer's station and mine, alongsides with a skype conversation. Their idea is that I'll say to the developer: show me file foo.php The developer will then open this foo.php file in his IDE. I'll have then to ask him to show me the bar method, the parent class, etc... Remember that it's a read-only session, so forget about putting a Zend_Debug::log() anywhere, and don't even think about a xDebug breakpoint (they don't use any kind of debugger, sic). Their client has also forbidden them to use any version control system... My first reaction when they explained to me this was (and I actually did say it outloud to them): Well, find another client. but they took it as a joke from me. I understand that in a business point of view rejecting a client is not a good practice, but I think that the condition of this assignment make it impossible to complete. At least according to my workflow. I mean, the way I work or learn a new framework/program is: download all files and copy of db on my pc create a git repository and a branch run the application locally use breakpoints use Zend_Debug::log() write the code and tests commit to git repo upload to (test/staging first if there is one, production if not) server I have agreed to try the desktop sharing session, although I think it will be a waste of time. On one hand I don't mind, they pay me for that time, but I know me and I don't like the sensation of loosing my time. On the other hand, I have other clients for whom I can work according to my workflow. I am about to say to them that I cannot (don't want to) do it. Well, I'll first try this desktop sharing session: maybe I'm wrong and it can actually work. But I like to consider myself as a professional, and I know that I don't know everything. So I try to keep an open mind and I am always willing to learn new stuff. So my questions are: Can this desktop-sharing workflow work? What should be done in order to take the most of it? Taking into account all the obstacles (geographic locations, no local, no git), is there another way for me to work on that project?

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  • SQL Server: Writing CASE expressions properly when NULLs are involved

    - by Mladen Prajdic
    We’ve all written a CASE expression (yes, it’s an expression and not a statement) or two every now and then. But did you know there are actually 2 formats you can write the CASE expression in? This actually bit me when I was trying to add some new functionality to an old stored procedure. In some rare cases the stored procedure just didn’t work correctly. After a quick look it turned out to be a CASE expression problem when dealing with NULLS. In the first format we make simple “equals to” comparisons to a value: SELECT CASE <value> WHEN <equals this value> THEN <return this> WHEN <equals this value> THEN <return this> -- ... more WHEN's here ELSE <return this> END Second format is much more flexible since it allows for complex conditions. USE THIS ONE! SELECT CASE WHEN <value> <compared to> <value> THEN <return this> WHEN <value> <compared to> <value> THEN <return this> -- ... more WHEN's here ELSE <return this> END Now that we know both formats and you know which to use (the second one if that hasn’t been clear enough) here’s an example how the first format WILL make your evaluation logic WRONG. Run the following code for different values of @i. Just comment out any 2 out of 3 “SELECT @i =” statements. DECLARE @i INTSELECT  @i = -1 -- first resultSELECT  @i = 55 -- second resultSELECT  @i = NULL -- third resultSELECT @i AS OriginalValue, -- first CASE format. DON'T USE THIS! CASE @i WHEN -1 THEN '-1' WHEN NULL THEN 'We have a NULL!' ELSE 'We landed in ELSE' END AS DontUseThisCaseFormatValue, -- second CASE format. USE THIS! CASE WHEN @i = -1 THEN '-1' WHEN @i IS NULL THEN 'We have a NULL!' ELSE 'We landed in ELSE' END AS UseThisCaseFormatValue When the value of @i is –1 everything works as expected, since both formats go into the –1 WHEN branch. When the value of @i is 55 everything again works as expected, since both formats go into the ELSE branch. When the value of @i is NULL the problems become evident. The first format doesn’t go into the WHEN NULL branch because it makes an equality comparison between two NULLs. Because a NULL is an unknown value: NULL = NULL is false. That is why the first format goes into the ELSE Branch but the second format correctly handles the proper IS NULL comparison.   Please use the second more explicit format. Your future self will be very grateful to you when he doesn’t have to discover these kinds of bugs.

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  • F# Objects &ndash; Integration with the other .Net Languages &ndash; Part 2

    - by MarkPearl
    So in part one of my posting I covered the real basics of object creation. Today I will hopefully dig a little deeper… My expert F# book brings up an interesting point – properties in F# are just syntactic sugar for method calls. This makes sense… for instance assume I had the following object with the property exposed called Firstname. type Person(Firstname : string, Lastname : string) = member v.Firstname = Firstname I could extend the Firstname property with the following code and everything would be hunky dory… type Person(Firstname : string, Lastname : string) = member v.Firstname = Console.WriteLine("Side Effect") Firstname   All that this would do is each time I use the property Firstname, I would see the side effect printed to the screen saying “Side Effect”. Member methods have a very similar look & feel to properties, in fact the only difference really is that you declare that parameters are being passed in. type Person(Firstname : string, Lastname : string) = member v.FullName(middleName) = Firstname + " " + middleName + " " + Lastname   In the code above, FullName requires the parameter middleName, and if viewed from another project in C# would show as a method and not a property. Precomputation Optimizations Okay, so something that is obvious once you think of it but that poses an interesting side effect of mutable value holders is pre-computation of results. All it is, is a slight difference in code but can result in quite a huge saving in performance. Basically pre-computation means you would not need to compute a value every time a method is called – but could perform the computation at the creation of the object (I hope I have got it right). In a way I battle to differentiate this from lazy evaluation but I will show an example to explain the principle. Let me try and show an example to illustrate the principle… assume the following F# module namespace myNamespace open System module myMod = let Add val1 val2 = Console.WriteLine("Compute") val1 + val2 type MathPrecompute(val1 : int, val2 : int) = let precomputedsum = Add val1 val2 member v.Sum = precomputedsum type MathNormalCompute(val1 : int, val2 : int) = member v.Sum = Add val1 val2 Now assume you have a C# console app that makes use of the objects with code similar to the following… using System; using myNamespace; namespace CSharpTest { class Program { static void Main(string[] args) { Console.WriteLine("Constructing Objects"); var myObj1 = new myMod.MathNormalCompute(10, 11); var myObj2 = new myMod.MathPrecompute(10, 11); Console.WriteLine(""); Console.WriteLine("Normal Compute Sum..."); Console.WriteLine(myObj1.Sum); Console.WriteLine(myObj1.Sum); Console.WriteLine(myObj1.Sum); Console.WriteLine(""); Console.WriteLine("Pre Compute Sum..."); Console.WriteLine(myObj2.Sum); Console.WriteLine(myObj2.Sum); Console.WriteLine(myObj2.Sum); Console.ReadKey(); } } } The output when running the console application would be as follows…. You will notice with the normal compute object that the system would call the Add function every time the method was called. With the Precompute object it only called the compute method when the object was created. Subtle, but something that could lead to major performance benefits. So… this post has gone off in a slight tangent but still related to F# objects.

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  • How to restore/change Alt+Tab behaviour/ram usage and a few other things after Ubuntu upgrade from 11.04 to 11.10?

    - by fiktor
    I use Ubuntu for programming. I recently updated it from 11.04 to 11.10. There are some things I don't like in the new version of Unity desktop interface. I don't actually know if it is hard to restore previous behavior or not, and if it is not, where should I look to do that. I know a bit of programming, but I really don't know much about Linux settings. I used to have 3-6 terminal windows and switch between them with Alt+Tab and Shift+Alt+Tab. I liked half-transparent terminal windows, since with them I could open web-page with some instruction in Firefox, press Alt+Tab and type commands in a console window, being able to recognize text on a web-page under it. Now I have problems with my usual work-style because of the following. List of "negative" changes Alt+Tab shows just one icon for all console windows. When I wait some time, it, however, shows all windows, but I don't like to wait. I prefer to remember order of windows and press Alt+Tab as many times as I need to switch to the right window. Alt+Shift+Tab to switch in reverse order doesn't work now. Console windows are not transparent any more. When I don't wait, and switch to this icon, it shows all console windows altogether. So even if they were transparent, I wouldn't be able to see anything below them (I can read something only from the window, which is directly under current one, not a few levels under). When I run a few console windows in Unity I had 740Mb used on Ubuntu 11.04, but I have 1050Mb now. The question is how to make it back to 750-. I really need my memory, since I use my computer to work with 1512Mb of data and I try to save every 10Mb possible (if it doesn't take too much of machine and, more importantly, my time). When I press "The Super key" I have a field to type the name of the program I want to run. But now it sometimes shows this field, but when I'm trying to type nothing happens. Probably, focus is not on the right field. I don't really mean to restore exactly the same behavior, but I want to make my work in Ubuntu 11.10 efficient (at least as efficient as in Ubuntu 11.04). I would be happy if there are some ways to accomplish that. What have I tried I have installed CompizConfig Settings Manager. I have read this question. However enabling "Static Application Switcher" makes Alt+Tab crazy: after enabling it It says about key-binding conflicts with "Ubuntu Unity Plugin"; "Alt+Tab" switching doesn't change, but "Shift+Alt+Tab" now works and shows all windows; Memory usage increases. I have tried turning off Ubuntu Unity Plugin, but this doesn't seem right thing to do, since it seems to turn off all menus, a lot of keystrokes and app-launcher, which usually activates with "The Super key". I have found, that window transparency can be enabled by "Opacity, Brightness and Saturation" plugin from Accessibility. However I don't know if enabling it is the right thing to do (at least it increases memory usage). Update: everything solved but #3: see my own answer below. I have made a separate question about issue #3 (transparency).

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  • SSI: Failed String Comparison with CGI Environment Variable [migrated]

    - by Calyo Delphi
    I am currently working on developing a personal website. It's not my first time doing this, but this is my first major foray into implementing SSI. I've run myself into a wall, however, with an if-else directive that uses one of the CGI environment variables as part of its comparison. Even after some limited attempts at debugging, all of the output and documentation that I have means that the comparisons being made should fail outright. This is not the case, and the wrong evaluation is being made by the if-else directive. Here's the code in the file index.shtml: <head> <!--#set var="page" value="Home" --> <!--#include file="headlinks.shtml" --> <style> img#ref { float: right; margin-left: 8px; border-width: 0px; } </style> </head> Here's the code in the file headlinks.shtml: <title><!--#echo var="page" --> &ndash; <!--#echo var="HTTP_HOST" --></title> <!--#set var="docroot" value="${DOCUMENT_ROOT}" --> <!--#echo var="docroot" --> <!--#if expr="( $docroot != '/Applications/MAMP/htdocs' ) || ( $docroot != '/home/dragarch/public_html' )" --> <link rel="stylesheet" type="text/css" href="../style.css"> <link rel="shortcut icon" type="image/svg+xml" href="../favicon.svg" /> <!--#else --> <link rel="stylesheet" type="text/css" href="style.css"> <link rel="shortcut icon" type="image/svg+xml" href="favicon.svg" /> <!--#endif --> And here's the output for the file index.shtml: <title>Home &ndash; dragarch</title> /Applications/MAMP/htdocs <link rel="stylesheet" type="text/css" href="../style.css"> <link rel="shortcut icon" type="image/svg+xml" href="../favicon.svg" /> Both style.css and favicon.svg are in the document root with index.shtml, so the if directive should fail and default to the output of the else directive. As you can see, while the document root (which is currently the MAMP htdocs folder on my own notebook) is correct according to the output of the echo directive, the comparison in the if-else directive fails to compare the strings properly. I'm using this page for my documentation: http://httpd.apache.org/docs/2.2/mod/mod_include.html I'm at a complete loss as to why this is the case, and need a bit of help here. EDIT: I should note that dragarch is a hostname that I configured in /etc/hosts to point to 127.0.0.1 so I could test the site without having to use localhost. It has no real effect on the functionality of anything, other than to just act as a prettier hostname to use.

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  • How do you go from a so so programmer to a great one? [closed]

    - by Cervo
    How do you go from being an okay programmer to being able to write maintainable clean code? For example David Hansson was writing Basecamp when in the process he created Rails as part of writing Basecamp in a clean/maintainable way. But how do you know when there is value in a side project like that? I have a bachelors in computer science, and I am about to get a masters and I will say that colleges teach you to write code to solve problems, not neatly or anything. Basically you think of a problem, come up with a solution, and write it down...not necessarily the most maintainable way in the world. Also my first job was in a startup, and now my third is in a small team in a large company where the attitude was/is get it done yesterday (also most of my jobs are mainly database development with SQL with a few ASP.NET web pages/.NET apps on the side). So of course cut/paste is more favored than making things more cleanly. And they would rather have something yesterday even if you have to rewrite it next month rather than to have something in a week that lasts for a year. Also spaghetti code turns up all over the place, and it takes very smart people to write/understand/maintain spaghetti code...However it would be better to do things so simple/clean that even a caveman/woman could do maintenance. Also I get very bored/unmotivated having to go modify the same things cut/pasted in a few locations. Is this the type of skill that you need to learn by working with a serious software organization that has an emphasis on maintenance and maybe even an architect who designs a system architecture and reviews code? Could you really learn it by volunteering on an open source project (it seems to me that a full time programmer job is way more practice than a few hours a week on an open source project)? Is there some course where you can learn this? I can attest that graduate school and undergraduate school do not really emphasize clean software at all. They just teach the structures/algorithms and then send you off into the world to solve problems. Overall I think the first thing is learning to write clean/maintainable code within the bounds of the project in order to become a good programmer. Then the next thing is learning when you need to do a side project (like a framework) to make things more maintainable/clean even while you still deliver things for the deadline in order to become a great programmer. For example, you are making an SQL report and someone gives you 100 calculations for individual columns. At what point does it make sense to construct a domain specific language to encode the rules in simply and then generate all the SQL as opposed to cut/pasting the query from the table a bunch of times and then adjusting each query to do the appropriate calculations. This is the type of thing I would say a great programmer would know. He/she would maybe even know ways to avoid the domain specific language and to still do all the calculations without creating an unmaintainable mess or a ton of repetitive code to cut/paste everywhere.

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  • How can I change the color of the text in my iFrame? [closed]

    - by VinylScratch
    I have code here: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>Frag United Banlist</title> </head> <body> <h1>Tekkit Banlist</h1> <?php // change these things $server = "server-host"; $dbuser = "correct-user"; $dbpass = "correct-password"; $dbname = "correct-database"; mysql_connect($server, $dbuser, $dbpass); mysql_select_db($dbname); $result = mysql_query("SELECT * FROM banlist ORDER BY id DESC"); //This will display the most recent by id edit this query how you see fit. Limit, Order, ect. echo "<table width=100% border=1 cellpadding=3 cellspacing=0>"; echo "<tr style=\"font-weight:bold\"> <td>ID</td> <td>User</td> <td>Reason</td> <td>Admin/Mod</td> <td>Time</td> <td>Ban Length</td> </tr>"; while($row = mysql_fetch_assoc($result)){ if($col == "#eeeeee"){ $col = "#ffffff"; }else{ $col = "#eeeeee"; } echo "<tr bgcolor=$col>"; echo "<td>".$row['id']."</td>"; echo "<td>".$row['user']."</td>"; echo "<td>".$row['reason']."</td>"; echo "<td>".$row['admin']."</td>"; //Convert Epoch Time to Standard format $datetime = date("F j, Y, g:i a", $row['time']); echo "<td>$datetime</td>"; $dateconvert = date("F j, Y, g:i a", $row['length']); if($row['length'] == "0"){ echo "<td>None</td>"; }else{ echo "<td>$dateconvert</td>"; } echo "<td>".$row['id']."</td>"; echo "</tr>"; } echo"</table>" ?> </div> </body></html> And I am trying to make it so that when I put it in this iframe: <iframe src="http://bans.fragunited.net/" width="100%" length="100%"><p>Your browser does not support iframes.</p></iframe> But if you go to this page, fragunited.net/bans, (not bans.fragunited.net) the text is black and I want it to be white so you can actually see it. Sorry for the large amount of code, however I don't know where you have to put the code to change the color.

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  • Use IIS Application Initialization for keeping ASP.NET Apps alive

    - by Rick Strahl
    I've been working quite a bit with Windows Services in the recent months, and well, it turns out that Windows Services are quite a bear to debug, deploy, update and maintain. The process of getting services set up,  debugged and updated is a major chore that has to be extensively documented and or automated specifically. On most projects when a service is built, people end up scrambling for the right 'process' to use for administration. Web app deployment and maintenance on the other hand are common and well understood today, as we are constantly dealing with Web apps. There's plenty of infrastructure and tooling built into Web Tools like Visual Studio to facilitate the process. By comparison Windows Services or anything self-hosted for that matter seems convoluted.In fact, in a recent blog post I mentioned that on a recent project I'd been using self-hosting for SignalR inside of a Windows service, because the application is in fact a 'service' that also needs to send out lots of messages via SignalR. But the reality is that it could just as well be an IIS application with a service component that runs in the background. Either way you look at it, it's either a Windows Service with a built in Web Server, or an IIS application running a Service application, neither of which follows the standard Service or Web App template.Personally I much prefer Web applications. Running inside of IIS I get all the benefits of the IIS platform including service lifetime management (crash and restart), controlled shutdowns, the whole security infrastructure including easy certificate support, hot-swapping of code and the the ability to publish directly to IIS from within Visual Studio with ease.Because of these benefits we set out to move from the self hosted service into an ASP.NET Web app instead.The Missing Link for ASP.NET as a Service: Auto-LoadingI've had moments in the past where I wanted to run a 'service like' application in ASP.NET because when you think about it, it's so much easier to control a Web application remotely. Services are locked into start/stop operations, but if you host inside of a Web app you can write your own ticket and control it from anywhere. In fact nearly 10 years ago I built a background scheduling application that ran inside of ASP.NET and it worked great and it's still running doing its job today.The tricky part for running an app as a service inside of IIS then and now, is how to get IIS and ASP.NET launched so your 'service' stays alive even after an Application Pool reset. 7 years ago I faked it by using a web monitor (my own West Wind Web Monitor app) I was running anyway to monitor my various web sites for uptime, and having the monitor ping my 'service' every 20 seconds to effectively keep ASP.NET alive or fire it back up after a reload. I used a simple scheduler class that also includes some logic for 'self-reloading'. Hacky for sure, but it worked reliably.Luckily today it's much easier and more integrated to get IIS to launch ASP.NET as soon as an Application Pool is started by using the Application Initialization Module. The Application Initialization Module basically allows you to turn on Preloading on the Application Pool and the Site/IIS App, which essentially fires a request through the IIS pipeline as soon as the Application Pool has been launched. This means that effectively your ASP.NET app becomes active immediately, Application_Start is fired making sure your app stays up and running at all times. All the other features like Application Pool recycling and auto-shutdown after idle time still work, but IIS will then always immediately re-launch the application.Getting started with Application InitializationAs of IIS 8 Application Initialization is part of the IIS feature set. For IIS 7 and 7.5 there's a separate download available via Web Platform Installer. Using IIS 8 Application Initialization is an optional install component in Windows or the Windows Server Role Manager: This is an optional component so make sure you explicitly select it.IIS Configuration for Application InitializationInitialization needs to be applied on the Application Pool as well as the IIS Application level. As of IIS 8 these settings can be made through the IIS Administration console.Start with the Application Pool:Here you need to set both the Start Automatically which is always set, and the StartMode which should be set to AlwaysRunning. Both have to be set - the Start Automatically flag is set true by default and controls the starting of the application pool itself while Always Running flag is required in order to launch the application. Without the latter flag set the site settings have no effect.Now on the Site/Application level you can specify whether the site should pre load: Set the Preload Enabled flag to true.At this point ASP.NET apps should auto-load. This is all that's needed to pre-load the site if all you want is to get your site launched automatically.If you want a little more control over the load process you can add a few more settings to your web.config file that allow you to show a static page while the App is starting up. This can be useful if startup is really slow, so rather than displaying blank screen while the user is fiddling their thumbs you can display a static HTML page instead: <system.webServer> <applicationInitialization remapManagedRequestsTo="Startup.htm" skipManagedModules="true"> <add initializationPage="ping.ashx" /> </applicationInitialization> </system.webServer>This allows you to specify a page to execute in a dry run. IIS basically fakes request and pushes it directly into the IIS pipeline without hitting the network. You specify a page and IIS will fake a request to that page in this case ping.ashx which just returns a simple OK string - ie. a fast pipeline request. This request is run immediately after Application Pool restart, and while this request is running and your app is warming up, IIS can display an alternate static page - Startup.htm above. So instead of showing users an empty loading page when clicking a link on your site you can optionally show some sort of static status page that says, "we'll be right back".  I'm not sure if that's such a brilliant idea since this can be pretty disruptive in some cases. Personally I think I prefer letting people wait, but at least get the response they were supposed to get back rather than a random page. But it's there if you need it.Note that the web.config stuff is optional. If you don't provide it IIS hits the default site link (/) and even if there's no matching request at the end of that request it'll still fire the request through the IIS pipeline. Ideally though you want to make sure that an ASP.NET endpoint is hit either with your default page, or by specify the initializationPage to ensure ASP.NET actually gets hit since it's possible for IIS fire unmanaged requests only for static pages (depending how your pipeline is configured).What about AppDomain Restarts?In addition to full Worker Process recycles at the IIS level, ASP.NET also has to deal with AppDomain shutdowns which can occur for a variety of reasons:Files are updated in the BIN folderWeb Deploy to your siteweb.config is changedHard application crashThese operations don't cause the worker process to restart, but they do cause ASP.NET to unload the current AppDomain and start up a new one. Because the features above only apply to Application Pool restarts, AppDomain restarts could also cause your 'ASP.NET service' to stop processing in the background.In order to keep the app running on AppDomain recycles, you can resort to a simple ping in the Application_End event:protected void Application_End() { var client = new WebClient(); var url = App.AdminConfiguration.MonitorHostUrl + "ping.aspx"; client.DownloadString(url); Trace.WriteLine("Application Shut Down Ping: " + url); }which fires any ASP.NET url to the current site at the very end of the pipeline shutdown which in turn ensures that the site immediately starts back up.Manual Configuration in ApplicationHost.configThe above UI corresponds to the following ApplicationHost.config settings. If you're using IIS 7, there's no UI for these flags so you'll have to manually edit them.When you install the Application Initialization component into IIS it should auto-configure the module into ApplicationHost.config. Unfortunately for me, with Mr. Murphy in his best form for me, the module registration did not occur and I had to manually add it.<globalModules> <add name="ApplicationInitializationModule" image="%windir%\System32\inetsrv\warmup.dll" /> </globalModules>Most likely you won't need ever need to add this, but if things are not working it's worth to check if the module is actually registered.Next you need to configure the ApplicationPool and the Web site. The following are the two relevant entries in ApplicationHost.config.<system.applicationHost> <applicationPools> <add name="West Wind West Wind Web Connection" autoStart="true" startMode="AlwaysRunning" managedRuntimeVersion="v4.0" managedPipelineMode="Integrated"> <processModel identityType="LocalSystem" setProfileEnvironment="true" /> </add> </applicationPools> <sites> <site name="Default Web Site" id="1"> <application path="/MPress.Workflow.WebQueueMessageManager" applicationPool="West Wind West Wind Web Connection" preloadEnabled="true"> <virtualDirectory path="/" physicalPath="C:\Clients\…" /> </application> </site> </sites> </system.applicationHost>On the Application Pool make sure to set the autoStart and startMode flags to true and AlwaysRunning respectively. On the site make sure to set the preloadEnabled flag to true.And that's all you should need. You can still set the web.config settings described above as well.ASP.NET as a Service?In the particular application I'm working on currently, we have a queue manager that runs as standalone service that polls a database queue and picks out jobs and processes them on several threads. The service can spin up any number of threads and keep these threads alive in the background while IIS is running doing its own thing. These threads are newly created threads, so they sit completely outside of the IIS thread pool. In order for this service to work all it needs is a long running reference that keeps it alive for the life time of the application.In this particular app there are two components that run in the background on their own threads: A scheduler that runs various scheduled tasks and handles things like picking up emails to send out outside of IIS's scope and the QueueManager. Here's what this looks like in global.asax:public class Global : System.Web.HttpApplication { private static ApplicationScheduler scheduler; private static ServiceLauncher launcher; protected void Application_Start(object sender, EventArgs e) { // Pings the service and ensures it stays alive scheduler = new ApplicationScheduler() { CheckFrequency = 600000 }; scheduler.Start(); launcher = new ServiceLauncher(); launcher.Start(); // register so shutdown is controlled HostingEnvironment.RegisterObject(launcher); }}By keeping these objects around as static instances that are set only once on startup, they survive the lifetime of the application. The code in these classes is essentially unchanged from the Windows Service code except that I could remove the various overrides required for the Windows Service interface (OnStart,OnStop,OnResume etc.). Otherwise the behavior and operation is very similar.In this application ASP.NET serves two purposes: It acts as the host for SignalR and provides the administration interface which allows remote management of the 'service'. I can start and stop the service remotely by shutting down the ApplicationScheduler very easily. I can also very easily feed stats from the queue out directly via a couple of Web requests or (as we do now) through the SignalR service.Registering a Background Object with ASP.NETNotice also the use of the HostingEnvironment.RegisterObject(). This function registers an object with ASP.NET to let it know that it's a background task that should be notified if the AppDomain shuts down. RegisterObject() requires an interface with a Stop() method that's fired and allows your code to respond to a shutdown request. Here's what the IRegisteredObject::Stop() method looks like on the launcher:public void Stop(bool immediate = false) { LogManager.Current.LogInfo("QueueManager Controller Stopped."); Controller.StopProcessing(); Controller.Dispose(); Thread.Sleep(1500); // give background threads some time HostingEnvironment.UnregisterObject(this); }Implementing IRegisterObject should help with reliability on AppDomain shutdowns. Thanks to Justin Van Patten for pointing this out to me on Twitter.RegisterObject() is not required but I would highly recommend implementing it on whatever object controls your background processing to all clean shutdowns when the AppDomain shuts down.Testing it outI'm still in the testing phase with this particular service to see if there are any side effects. But so far it doesn't look like it. With about 50 lines of code I was able to replace the Windows service startup to Web start up - everything else just worked as is. An honorable mention goes to SignalR 2.0's oWin hosting, because with the new oWin based hosting no code changes at all were required, merely a couple of configuration file settings and an assembly directive needed, to point at the SignalR startup class. Sweet!It also seems like SignalR is noticeably faster running inside of IIS compared to self-host. Startup feels faster because of the preload.Starting and Stopping the 'Service'Because the application is running as a Web Server, it's easy to have a Web interface for starting and stopping the services running inside of the service. For our queue manager the SignalR service and front monitoring app has a play and stop button for toggling the queue.If you want more administrative control and have it work more like a Windows Service you can also stop the application pool explicitly from the command line which would be equivalent to stopping and restarting a service.To start and stop from the command line you can use the IIS appCmd tool. To stop:> %windir%\system32\inetsrv\appcmd stop apppool /apppool.name:"Weblog"and to start> %windir%\system32\inetsrv\appcmd start apppool /apppool.name:"Weblog"Note that when you explicitly force the AppPool to stop running either in the UI (on the ApplicationPools page use Start/Stop) or via command line tools, the application pool will not auto-restart immediately. You have to manually start it back up.What's not to like?There are certainly a lot of benefits to running a background service in IIS, but… ASP.NET applications do have more overhead in terms of memory footprint and startup time is a little slower, but generally for server applications this is not a big deal. If the application is stable the service should fire up and stay running indefinitely. A lot of times this kind of service interface can simply be attached to an existing Web application, or if scalability requires be offloaded to its own Web server.Easier to work withBut the ultimate benefit here is that it's much easier to work with a Web app as opposed to a service. While developing I can simply turn off the auto-launch features and launch the service on demand through IIS simply by hitting a page on the site. If I want to shut down an IISRESET -stop will shut down the service easily enough. I can then attach a debugger anywhere I want and this works like any other ASP.NET application. Yes you end up on a background thread for debugging but Visual Studio handles that just fine and if you stay on a single thread this is no different than debugging any other code.SummaryUsing ASP.NET to run background service operations is probably not a super common scenario, but it probably should be something that is considered carefully when building services. Many applications have service like features and with the auto-start functionality of the Application Initialization module, it's easy to build this functionality into ASP.NET. Especially when combined with the notification features of SignalR it becomes very, very easy to create rich services that can also communicate their status easily to the outside world.Whether it's existing applications that need some background processing for scheduling related tasks, or whether you just create a separate site altogether just to host your service it's easy to do and you can leverage the same tool chain you're already using for other Web projects. If you have lots of service projects it's worth considering… give it some thought…© Rick Strahl, West Wind Technologies, 2005-2013Posted in ASP.NET  SignalR  IIS   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Q1 2010 New Feature: Paging with RadGridView for Silverlight and WPF

    We are glad to announce that the Q1 2010 Release has added another weapon to RadGridViews growing arsenal of features. This is the brand new RadDataPager control which provides the user interface for paging through a collection of data. The good news is that RadDataPager can be used to page any collection. It does not depend on RadGridView in any way, so you will be free to use it with the rest of your ItemsControls if you chose to do so. Before you read on, you might want to download the samples solution that I have attached. It contains a sample project for every scenario that I will discuss later on. Looking at the code while reading will make things much easier for you. There is something for everyone among the 10 Visual Studio projects that are included in the solution. So go and grab it. I. Paging essentials The single most important piece of software concerning paging in Silverlight is the System.ComponentModel.IPagedCollectionView interface. Those of you who are on the WPF front need not worry though. As you might already know, Teleriks Silverlight and WPF controls is share the same code-base. Since WPF does not contain a similar interface, Telerik has provided its own Telerik.Windows.Data.IPagedCollectionView. The IPagedCollectionView interface contains several important members which are used by RadGridView to perform the actual paging. Silverlight provides a default implementation of this interface which, naturally, is called PagedCollectionView. You should definitely take a look at its source code in case you are interested in what is going on under the hood. But this is not a prerequisite for our discussion. The WPF default implementation of the interface is Teleriks QueryableCollectionView which, among many other interfaces, implements IPagedCollectionView. II. No Paging In order to gradually build up my case, I will start with a very simple example that lacks paging whatsoever. It might sound stupid, but this will help us build on top of this paging-devoid example. Let us imagine that we have the simplest possible scenario. That is a simple IEnumerable and an ItemsControl that shows its contents. This will look like this: No Paging IEnumerable itemsSource = Enumerable.Range(0, 1000); this.itemsControl.ItemsSource = itemsSource; XAML <Border Grid.Row="0" BorderBrush="Black" BorderThickness="1" Margin="5">     <ListBox Name="itemsControl"/> </Border> <Border Grid.Row="1" BorderBrush="Black" BorderThickness="1" Margin="5">     <TextBlock Text="No Paging"/> </Border> Nothing special for now. Just some data displayed in a ListBox. The two sample projects in the solution that I have attached are: NoPaging_WPF NoPaging_SL3 With every next sample those two project will evolve in some way or another. III. Paging simple collections The single most important property of RadDataPager is its Source property. This is where you pass in your collection of data for paging. More often than not your collection will not be an IPagedCollectionView. It will either be a simple List<T>, or an ObservableCollection<T>, or anything that is simply IEnumerable. Unless you had paging in mind when you designed your project, it is almost certain that your data source will not be pageable out of the box. So what are the options? III. 1. Wrapping the simple collection in an IPagedCollectionView If you look at the constructors of PagedCollectionView and QueryableCollectionView you will notice that you can pass in a simple IEnumerable as a parameter. Those two classes will wrap it and provide paging capabilities over your original data. In fact, this is what RadGridView does internally. It wraps your original collection in an QueryableCollectionView in order to easily perform many useful tasks such as filtering, sorting, and others, but in our case the most important one is paging. So let us start our series of examples with the most simplistic one. Imagine that you have a simple IEnumerable which is the source for an ItemsControl. Here is how to wrap it in order to enable paging: Silverlight IEnumerable itemsSource = Enumerable.Range(0, 1000); var pagedSource = new PagedCollectionView(itemsSource); this.radDataPager.Source = pagedSource; this.itemsControl.ItemsSource = pagedSource; WPF IEnumerable itemsSource = Enumerable.Range(0, 1000); var pagedSource = new QueryableCollectionView(itemsSource); this.radDataPager.Source = pagedSource; this.itemsControl.ItemsSource = pagedSource; XAML <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <ListBox Name="itemsControl"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> This will do the trick. It is quite simple, isnt it? The two sample projects in the solution that I have attached are: PagingSimpleCollectionWithWrapping_WPF PagingSimpleCollectionWithWrapping_SL3 III. 2. Binding to RadDataPager.PagedSource In case you do not like this approach there is a better one. When you assign an IEnumerable as the Source of a RadDataPager it will automatically wrap it in a QueryableCollectionView and expose it through its PagedSource property. From then on, you can attach any number of ItemsControls to the PagedSource and they will be automatically paged. Here is how to do this entirely in XAML: Using RadDataPager.PagedSource <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1" Margin="5">     <ListBox Name="itemsControl"              ItemsSource="{Binding PagedSource, ElementName=radDataPager}"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               Source="{Binding ItemsSource}"                              PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> The two sample projects in the solution that I have attached are: PagingSimpleCollectionWithPagedSource_WPF PagingSimpleCollectionWithPagedSource_SL3 IV. Paging collections implementing IPagedCollectionView Those of you who are using WCF RIA Services should feel very lucky. After a quick look with Reflector or the debugger we can see that the DomainDataSource.Data property is in fact an instance of the DomainDataSourceView class. This class implements a handful of useful interfaces: ICollectionView IEnumerable INotifyCollectionChanged IEditableCollectionView IPagedCollectionView INotifyPropertyChanged Luckily, IPagedCollectionView is among them which lets you do the whole paging in the server. So lets do this. We will add a DomainDataSource control to our page/window and connect the items control and the pager to it. Here is how to do this: MainPage <riaControls:DomainDataSource x:Name="invoicesDataSource"                               AutoLoad="True"                               QueryName="GetInvoicesQuery">     <riaControls:DomainDataSource.DomainContext>         <services:ChinookDomainContext/>     </riaControls:DomainDataSource.DomainContext> </riaControls:DomainDataSource> <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <ListBox Name="itemsControl"              ItemsSource="{Binding Data, ElementName=invoicesDataSource}"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               Source="{Binding Data, ElementName=invoicesDataSource}"                              PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> By the way, you can replace the ListBox from the above code snippet with any other ItemsControl. It can be RadGridView, it can be the MS DataGrid, you name it. Essentially, RadDataPager is sending paging commands to the the DomainDataSource.Data. It does not care who, what, or how many different controls are bound to this same Data property of the DomainDataSource control. So if you would like to experiment with this, you can throw in any number of other ItemsControls next to the ListBox, bind them in the same manner, and all of them will be paged by our single RadDataPager. Furthermore, you can throw in any number of RadDataPagers and bind them to the same property. Then when you page with any one of them will automatically update all of the rest. The whole picture is simply beautiful and we can do all of this thanks to WCF RIA Services. The two sample projects (Silverlight only) in the solution that I have attached are: PagingIPagedCollectionView PagingIPagedCollectionView.Web IV. Paging RadGridView While you can replace the ListBox in any of the above examples with a RadGridView, RadGridView offers something extra. Similar to the DomainDataSource.Data property, the RadGridView.Items collection implements the IPagedCollectionView interface. So you are already thinking: Then why not bind the Source property of RadDataPager to RadGridView.Items? Well thats exactly what you can do and you will start paging RadGridView out-of-the-box. It is as simple as that, no code-behind is involved: MainPage <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1" Margin="5">     <telerikGrid:RadGridView Name="radGridView"                              ItemsSource="{Binding ItemsSource}"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               Source="{Binding Items, ElementName=radGridView}"                              PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> The two sample projects in the solution that I have attached are: PagingRadGridView_SL3 PagingRadGridView_WPF With this last example I think I have covered every possible paging combination. In case you would like to see an example of something that I have not covered, please let me know. Also, make sure you check out those great online examples: WCF RIA Services with DomainDataSource Paging Configurator Endless Paging Paging Any Collection Paging RadGridView Happy Paging! Download Full Source Code Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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