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  • How does interpolation actually work to smooth out an object's movement?

    - by user22241
    I've asked a few similar questions over the past 8 months or so with no real joy, so I am going make the question more general. I have an Android game which is OpenGL ES 2.0. within it I have the following Game Loop: My loop works on a fixed time step principle (dt = 1 / ticksPerSecond) loops=0; while(System.currentTimeMillis() > nextGameTick && loops < maxFrameskip){ updateLogic(dt); nextGameTick+=skipTicks; timeCorrection += (1000d/ticksPerSecond) % 1; nextGameTick+=timeCorrection; timeCorrection %=1; loops++; } render(); My intergration works like this: sprite.posX+=sprite.xVel*dt; sprite.posXDrawAt=sprite.posX*width; Now, everything works pretty much as I would like. I can specify that I would like an object to move across a certain distance (screen width say) in 2.5 seconds and it will do just that. Also because of the frame skipping that I allow in my game loop, I can do this on pretty much any device and it will always take 2.5 seconds. Problem However, the problem is that when a render frame skips, the graphic stutter. It's extremely annoying. If I remove the ability to skip frames, then everything is smooth as you like, but will run at different speeds on different devices. So it's not an option. I'm still not sure why the frame skips, but I would like to point out that this is Nothing to do with poor performance, I've taken the code right back to 1 tiny sprite and no logic (apart from the logic required to move the sprite) and I still get skipped frames. And this is on a Google Nexus 10 tablet (and as mentioned above, I need frame skipping to keep the speed consistent across devices anyway). So, the only other option I have is to use interpolation (or extrapolation), I've read every article there is out there but none have really helped me to understand how it works and all of my attempted implementations have failed. Using one method I was able to get things moving smoothly but it was unworkable because it messed up my collision. I can foresee the same issue with any similar method because the interpolation is passed to (and acted upon within) the rendering method - at render time. So if Collision corrects position (character now standing right next to wall), then the renderer can alter it's position and draw it in the wall. So I'm really confused. People have said that you should never alter an object's position from within the rendering method, but all of the examples online show this. So I'm asking for a push in the right direction, please do not link to the popular game loop articles (deWitters, Fix your timestep, etc) as I've read these multiple times. I'm not asking anyone to write my code for me. Just explain please in simple terms how Interpolation actually works with some examples. I will then go and try to integrate any ideas into my code and will ask more specific questions if need-be further down the line. (I'm sure this is a problem many people struggle with).

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  • Clever memory usage through the years

    - by Ben Emmett
    A friend and I were recently talking about the really clever tricks people have used to get the most out of memory. I thought I’d share my favorites, and would love to hear yours too! Interleaving on drum memory Back in the ye olde days before I’d been born (we’re talking the 50s / 60s here), working memory commonly took the form of rotating magnetic drums. These would spin at a constant speed, and a fixed head would read from memory when the correct part of the drum passed it by, a bit like a primitive platter disk. Because each revolution took a few milliseconds, programmers took to manually arranging information non-sequentially on the drum, timing when an instruction or memory address would need to be accessed, then spacing information accordingly around the edge of the drum, thus reducing the access delay. Similar techniques were still used on hard disks and floppy disks into the 90s, but have become irrelevant with modern disk technologies. The Hashlife algorithm Conway’s Game of Life has attracted numerous implementations over the years, but Bill Gosper’s Hashlife algorithm is particularly impressive. Taking advantage of the repetitive nature of many cellular automata, it uses a quadtree structure to store the hashes of pieces of the overall grid. Over time there are fewer and fewer new structures which need to be evaluated, so it starts to run faster with larger grids, drastically outperforming other algorithms both in terms of speed and the size of grid which can be simulated. The actual amount of memory used is huge, but it’s used in a clever way, so makes the list . Elite’s procedural generation Ok, so this isn’t exactly a memory optimization – more a storage optimization – but it gets an honorable mention anyway. When writing Elite, David Braben and Ian Bell wanted to build a rich world which gamers could explore, but their 22K memory was something of a limitation (for comparison that’s about the size of my avatar picture at the top of this page). They procedurally generated all the characteristics of the 2048 planets in their virtual universe, including the names, which were stitched together using a lookup table of parts of names. In fact the original plans were for 2^52 planets, but it was decided that that was probably too many. Oh, and they did that all in assembly language. Other games of the time used similar techniques too – The Sentinel’s landscape generation algorithm being another example. Modern Garbage Collectors Garbage collection in managed languages like Java and .NET ensures that most of the time, developers stop needing to care about how they use and clean up memory as the garbage collector handles it automatically. Achieving this without killing performance is a near-miraculous feet of software engineering. Much like when learning chemistry, you find that every time you think you understand how the garbage collector works, it turns out to be a mere simplification; that there are yet more complexities and heuristics to help it run efficiently. Of course introducing memory problems is still possible (and there are tools like our memory profiler to help if that happens to you) but they’re much, much rarer. A cautionary note In the examples above, there were good and well understood reasons for the optimizations, but cunningly optimized code has usually had to trade away readability and maintainability to achieve its gains. Trying to optimize memory usage without being pretty confident that there’s actually a problem is doing it wrong. So what have I missed? Tell me about the ingenious (or stupid) tricks you’ve seen people use. Ben

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

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

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  • Logging errors caused by exceptions deep in the application

    - by Kaleb Pederson
    What are best-practices for logging deep within an application's source? Is it bad practice to have multiple event log entries for a single error? For example, let's say that I have an ETL system whose transform step involves: a transformer, pipeline, processing algorithm, and processing engine. In brief, the transformer takes in an input file, parses out records, and sends the records through the pipeline. The pipeline aggregates the results of the processing algorithm (which could do serial or parallel processing). The processing algorithm sends each record through one or more processing engines. So, I have at least four levels: Transformer - Pipeline - Algorithm - Engine. My code might then look something like the following: class Transformer { void Process(InputSource input) { try { var inRecords = _parser.Parse(input.Stream); var outRecords = _pipeline.Transform(inRecords); } catch (Exception ex) { var inner = new ProcessException(input, ex); _logger.Error("Unable to parse source " + input.Name, inner); throw inner; } } } class Pipeline { IEnumerable<Result> Transform(IEnumerable<Record> records) { // NOTE: no try/catch as I have no useful information to provide // at this point in the process var results = _algorithm.Process(records); // examine and do useful things with results return results; } } class Algorithm { IEnumerable<Result> Process(IEnumerable<Record> records) { var results = new List<Result>(); foreach (var engine in Engines) { foreach (var record in records) { try { engine.Process(record); } catch (Exception ex) { var inner = new EngineProcessingException(engine, record, ex); _logger.Error("Engine {0} unable to parse record {1}", engine, record); throw inner; } } } } } class Engine { Result Process(Record record) { for (int i=0; i<record.SubRecords.Count; ++i) { try { Validate(record.subRecords[i]); } catch (Exception ex) { var inner = new RecordValidationException(record, i, ex); _logger.Error( "Validation of subrecord {0} failed for record {1}", i, record ); } } } } There's a few important things to notice: A single error at the deepest level causes three log entries (ugly? DOS?) Thrown exceptions contain all important and useful information Logging only happens when failure to do so would cause loss of useful information at a lower level. Thoughts and concerns: I don't like having so many log entries for each error I don't want to lose important, useful data; the exceptions contain all the important but the stacktrace is typically the only thing displayed besides the message. I can log at different levels (e.g., warning, informational) The higher level classes should be completely unaware of the structure of the lower-level exceptions (which may change as the different implementations are replaced). The information available at higher levels should not be passed to the lower levels. So, to restate the main questions: What are best-practices for logging deep within an application's source? Is it bad practice to have multiple event log entries for a single error?

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  • How would I handle input with a Game Component?

    - by Aufziehvogel
    I am currently having problems from finding my way into the component-oriented XNA design. I read an overview over the general design pattern and googled a lot of XNA examples. However, they seem to be right on the opposite site. In the general design pattern, an object (my current player) is passed to InputComponent::update(Player). This means the class will know what to do and how this will affect the game (e.g. move person vs. scroll text in a menu). Yet, in XNA GameComponent::update(GameTime) is called automatically without a reference to the current player. The only XNA examples I found built some sort of higher-level Keyboard engine into the game component like this: class InputComponent: GameComponent { public void keyReleased(Keys); public void keyPressed(Keys); public bool keyDown(Keys); public void override update(GameTime gameTime) { // compare previous state with current state and // determine if released, pressed, down or nothing } } Some others went a bit further making it possible to use a Service Locator by a design like this: interface IInputComponent { public void downwardsMovement(Keys); public void upwardsMovement(Keys); public bool pausedGame(Keys); // determine which keys pressed and what that means // can be done for different inputs in different implementations public void override update(GameTime); } Yet, then I am wondering if it is possible to design an input class to resolve all possible situations. Like in a menu a mouse click can mean "click that button", but in game play it can mean "shoot that weapon". So if I am using such a modular design with game components for input, how much logic is to be put into the InputComponent / KeyboardComponent / GamepadComponent and where is the rest handled? What I had in mind, when I heard about Game Components and Service Locator in XNA was something like this: use Game Components to run the InputHandler automatically in the loop use Service Locator to be able to switch input at runtime (i.e. let player choose if he wants to use a gamepad or a keyboard; or which shall be player 1 and which player 2). However, now I cannot see how this can be done. First code example does not seem flexible enough, as on a game pad you could require some combination of buttons for something that is possible on keyboard with only one button or with the mouse) The second code example seems really hard to implement, because the InputComponent has to know in which context we are currently. Moreover, you could imagine your application to be multi-layered and let the key-stroke go through all layers to the bottom-layer which requires a different behaviour than the InputComponent would have guessed from the top-layer. The general design pattern with passing the Player to update() does not have a representation in XNA and I also cannot see how and where to decide which class should be passed to update(). At most time of course the player, but sometimes there could be menu items you have to or can click I see that the question in general is already dealt with here, but probably from a more elobate point-of-view. At least, I am not smart enough in game development to understand it. I am searching for a rather code-based example directly for XNA. And the answer there leaves (a noob like) me still alone in how the object that should receive the detected event is chosen. Like if I have a key-up event, should it go to the text box or to the player?

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  • Columnstore Case Study #1: MSIT SONAR Aggregations

    - by aspiringgeek
    Preamble This is the first in a series of posts documenting big wins encountered using columnstore indexes in SQL Server 2012 & 2014.  Many of these can be found in this deck along with details such as internals, best practices, caveats, etc.  The purpose of sharing the case studies in this context is to provide an easy-to-consume quick-reference alternative. Why Columnstore? If we’re looking for a subset of columns from one or a few rows, given the right indexes, SQL Server can do a superlative job of providing an answer. If we’re asking a question which by design needs to hit lots of rows—DW, reporting, aggregations, grouping, scans, etc., SQL Server has never had a good mechanism—until columnstore. Columnstore indexes were introduced in SQL Server 2012. However, they're still largely unknown. Some adoption blockers existed; yet columnstore was nonetheless a game changer for many apps.  In SQL Server 2014, potential blockers have been largely removed & they're going to profoundly change the way we interact with our data.  The purpose of this series is to share the performance benefits of columnstore & documenting columnstore is a compelling reason to upgrade to SQL Server 2014. App: MSIT SONAR Aggregations At MSIT, performance & configuration data is captured by SCOM. We archive much of the data in a partitioned data warehouse table in SQL Server 2012 for reporting via an application called SONAR.  By definition, this is a primary use case for columnstore—report queries requiring aggregation over large numbers of rows.  New data is refreshed each night by an automated table partitioning mechanism—a best practices scenario for columnstore. The Win Compared to performance using classic indexing which resulted in the expected query plan selection including partition elimination vs. SQL Server 2012 nonclustered columnstore, query performance increased significantly.  Logical reads were reduced by over a factor of 50; both CPU & duration improved by factors of 20 or more.  Other than creating the columnstore index, no special modifications or tweaks to the app or databases schema were necessary to achieve the performance improvements.  Existing nonclustered indexes were rendered superfluous & were deleted, thus mitigating maintenance challenges such as defragging as well as conserving disk capacity. Details The table provides the raw data & summarizes the performance deltas. Logical Reads (8K pages) CPU (ms) Durn (ms) Columnstore 160,323 20,360 9,786 Conventional Table & Indexes 9,053,423 549,608 193,903 ? x56 x27 x20 The charts provide additional perspective of this data.  "Conventional vs. Columnstore Metrics" document the raw data.  Note on this linear display the magnitude of the conventional index performance vs. columnstore.  The “Metrics (?)” chart expresses these values as a ratio. Summary For DW, reports, & other BI workloads, columnstore often provides significant performance enhancements relative to conventional indexing.  I have documented here, the first in a series of reports on columnstore implementations, results from an initial implementation at MSIT in which logical reads were reduced by over a factor of 50; both CPU & duration improved by factors of 20 or more.  Subsequent features in this series document performance enhancements that are even more significant. 

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  • Government Mandates and Programming Languages

    A recent SEC proposal (which, at over 600 pages, I havent read in any detail) includes the following: We are proposing to require the filing of a computer program (the waterfall computer program, as defined in the proposed rule) of the contractual cash flow provisions of the securities in the form of downloadable source code in Python, a commonly used computer programming language that is open source and interpretive. The computer program would be tagged in XML and required to be filed with the Commission as an exhibit. Under our proposal, the filed source code for the computer program, when downloaded and run (by loading it into an open Python session on the investors computer), would be required to allow the user to programmatically input information from the asset data file that we are proposing to require as described above. We believe that, with the waterfall computer program and the asset data file, investors would be better able to conduct their own evaluations of ABS and may be less likely to be dependent on the opinions of credit rating agencies. With respect to any registration statement on Form SF-1 (Section 239.44) or Form SF-3 (Section 239.45) relating to an offering of an asset-backed security that is required to comply with Item 1113(h) of Regulation AB, the Waterfall Computer Program (as defined in Item 1113(h)(1) of Regulation AB) must be written in the Python programming language and able to be downloaded and run on a local computer properly configured with a Python interpreter. The Waterfall Computer Program should be filed in the manner specified in the EDGAR Filer Manual. I dont see how it can be in investors best interests that the SEC demand a particular programming language be used for software related to investment data.  I have a feeling that investors who use computers at all already have software with which they are familiar, and that the vast majority of them are not running an open source scripting language on their machines to do their financial analysis.  In fact, I would wager that most of them are using tools like Excel, and if they really need to script anything, its being done with VBA in Excel. Now, Im not proposing that the SEC should require that the data be provided in Excel format with VBA scripts included so everyone can easily access the data (despite the fact that this would actually be pretty useful generally).  Rather, I think it is ill-advised for a government agency to make recommendations of this nature, period.  If the goal of the recommendation is to ensure that the way things work is codified in a transparent manner, than I can certainly respect that.  It seems to me that this could be accomplished without dictating the technology to use.  To wit: An Excel document could contain all of the data as well as the formulae necessary, and most likely would not require the end-user to install anything on their machine The SEC could simply create a calculator in the cloud such that any/all investors could use a single canonical web-based (or web service based) tool Millions of Java and .NET developers could write their own implementations You can read more about this issue, including the favorable position on it, on Jayanth Varmas blog. 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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  • Strategies for invoking subclass methods on generic objects

    - by Brad Patton
    I've run into this issue in a number of places and have solved it a bunch of different ways but looking for other solutions or opinions on how to address. The scenario is when you have a collection of objects all based off of the same superclass but you want to perform certain actions based only on instances of some of the subclasses. One contrived example of this might be an HTML document made up of elements. You could have a superclass named HTMLELement and subclasses of Headings, Paragraphs, Images, Comments, etc. To invoke a common action across all of the objects you declare a virtual method in the superclass and specific implementations in all of the subclasses. So to render the document you could loop all of the different objects in the document and call a common Render() method on each instance. It's the case where again using the same generic objects in the collection I want to perform different actions for instances of specific subclass (or set of subclasses). For example (an remember this is just an example) when iterating over the collection, elements with external links need to be downloaded (e.g. JS, CSS, images) and some might require additional parsing (JS, CSS). What's the best way to handle those special cases. Some of the strategies I've used or seen used include: Virtual methods in the base class. So in the base class you have a virtual LoadExternalContent() method that does nothing and then override it in the specific subclasses that need to implement it. The benefit being that in the calling code there is no object testing you send the same message to each object and let most of them ignore it. Two downsides that I can think of. First it can make the base class very cluttered with methods that have nothing to do with most of the hierarchy. Second it assumes all of the work can be done in the called method and doesn't handle the case where there might be additional context specific actions in the calling code (i.e. you want to do something in the UI and not the model). Have methods on the class to uniquely identify the objects. This could include methods like ClassName() which return a string with the class name or other return values like enums or booleans (IsImage()). The benefit is that the calling code can use if or switch statements to filter objects to perform class specific actions. The downside is that for every new class you need to implement these methods and can look cluttered. Also performance could be less than some of the other options. Use language features to identify objects. This includes reflection and language operators to identify the objects. For example in C# there is the is operator that returns true if the instance matches the specified class. The benefit is no additional code to implement in your object hierarchy. The only downside seems to be the lack of using something like a switch statement and the fact that your calling code is a little more cluttered. Are there other strategies I am missing? Thoughts on best approaches?

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  • JavaOne 2012: Nashorn Edition

    - by $utils.escapeXML($entry.author)
    As with my JavaOne 2012: OpenJDK Edition post a while back (now updated to reflect the schedule of the talks), I find it convenient to have my JavaOne schedule ordered by subjects of interest. Beside OpenJDK in all its flavors, another subject I find very exciting is Nashorn. I blogged about the various material on Nashorn in the past, and we interviewed Jim Laskey, the Project Lead on Project Nashorn in the Java Spotlight podcast. So without further ado, here are the JavaOne 2012 talks and BOFs with Nashorn in their title, or abstract:CON5390 - Nashorn: Optimizing JavaScript and Dynamic Language Execution on the JVM - Monday, Oct 1, 8:30 AM - 9:30 AMThere are many implementations of JavaScript, meant to run either on the JVM or standalone as native code. Both approaches have their respective pros and cons. The Oracle Nashorn JavaScript project is based on the former approach. This presentation goes through the performance work that has gone on in Oracle’s Nashorn JavaScript project to date in order to make JavaScript-to-bytecode generation for execution on the JVM feasible. It shows that the new invoke dynamic bytecode gets us part of the way there but may not quite be enough. What other tricks did the Nashorn project use? The presentation also discusses future directions for increased performance for dynamic languages on the JVM, covering proposed enhancements to both the JVM itself and to the bytecode compiler.CON4082 - Nashorn: JavaScript on the JVM - Monday, Oct 1, 3:00 PM - 4:00 PMThe JavaScript programming language has been experiencing a renaissance of late, driven by the interest in HTML5. Nashorn is a JavaScript engine implemented fully in Java on the JVM. It is based on the Da Vinci Machine (JSR 292) and will be available with JDK 8. This session describes the goals of Project Nashorn, gives a top-level view of how it all works, provides the current status, and demonstrates examples of JavaScript and Java working together.BOF4763 - Meet the Nashorn JavaScript Team - Tuesday, Oct 2, 4:30 PM - 5:15 PMCome to this session to meet the Oracle JavaScript (Project Nashorn) language teamBOF6661 - Nashorn, Node, and Java Persistence - Tuesday, Oct 2, 5:30 PM - 6:15 PMWith Project Nashorn, developers will have a full and modern JavaScript engine available on the JVM. In addition, they will have support for running Node applications with Node.jar. This unique combination of capabilities opens the door for best-of-breed applications combining Node with Java SE and Java EE. In this session, you’ll learn about Node.jar and how it can be combined with Java EE components such as EclipseLink JPA for rich Java persistence. You’ll also hear about all of Node.jar’s mapping, caching, querying, performance, and scaling features.CON10657 - The Polyglot Java VM and Java Middleware - Thursday, Oct 4, 12:30 PM - 1:30 PMIn this session, Red Hat and Oracle discuss the impact of polyglot programming from their own unique perspectives, examining non-Java languages that utilize Oracle’s Java HotSpot VM. You’ll hear a discussion of topics relating to Ruby, Lisp, and Clojure and the intersection of other languages where they may touch upon individual frameworks and projects, and you’ll get perspectives on JavaScript via the Nashorn Project, an upcoming JavaScript engine, developed fully in Java.CON5251 - Putting the Metaobject Protocol to Work: Nashorn’s Java Bindings - Thursday, Oct 4, 2:00 PM - 3:00 PMProject Nashorn is Oracle’s new JavaScript runtime in Java 8. Being a JavaScript runtime running on the JVM, it provides integration with the underlying runtime by enabling JavaScript objects to manipulate Java objects, implement Java interfaces, and extend Java classes. Nashorn is invokedynamic-based, and for its Java integration, it does away with the concept of wrapper objects in favor of direct virtual machine linking to Java objects’ methods provided by a metaobject protocol, providing much higher performance than what could be expected from a scripting runtime. This session looks at the details of the integration, a topic of interest to other language implementers on the JVM and a wider audience of developers who want to understand how Nashorn works.That's 6 sessions tooting the Nashorn this year at JavaOne, up from 2 last year.

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  • DBA Best Practices - A Blog Series: Episode 2 - Password Lists

    - by Argenis
      Digital World, Digital Locks One of the biggest digital assets that any company has is its secrets. These include passwords, key rings, certificates, and any other digital asset used to protect another asset from tampering or unauthorized access. As a DBA, you are very likely to manage some of these assets for your company - and your employer trusts you with keeping them safe. Probably one of the most important of these assets are passwords. As you well know, the can be used anywhere: for service accounts, credentials, proxies, linked servers, DTS/SSIS packages, symmetrical keys, private keys, etc., etc. Have you given some thought to what you're doing to keep these passwords safe? Are you backing them up somewhere? Who else besides you can access them? Good-Ol’ Post-It Notes Under Your Keyboard If you have a password-protected Excel sheet for your passwords, I have bad news for you: Excel's level of encryption is good for your grandma's budget spreadsheet, not for a list of enterprise passwords. I will try to summarize the main point of this best practice in one sentence: You should keep your passwords on an encrypted, access and version-controlled, backed-up, well-known shared location that every DBA on your team is aware of, and maintain copies of this password "database" on your DBA's workstations. Now I have to break down that statement to you: - Encrypted: what’s the point of saving your passwords on a file that any Windows admin with enough privileges can read? - Access controlled: This one is pretty much self-explanatory. - Version controlled: Passwords change (and I’m really hoping you do change them) and version control would allow you to track what a previous password was if the utility you’ve chosen doesn’t handle that for you. - Backed-up: You want a safe copy of the password list to be kept offline, preferably in long term storage, with relative ease of restoring. - Well-known shared location: This is critical for teams: what good is a password list if only one person in the team knows where it is? I have seen multiple examples of this that work well. They all start with an encrypted database. Certainly you could leverage SQL Server's native encryption solutions like cell encryption for this. I have found such implementations to be impractical, for the most part. Enter The World Of Utilities There are a myriad of open source/free software solutions to help you here. One of my favorites is KeePass, which creates encrypted files that can be saved to a network share, Sharepoint, etc. KeePass has UIs for most operating systems, including Windows, MacOS, iOS, Android and Windows Phone. Other solutions I've used before worth mentioning include PasswordSafe and 1Password, with the latter one being a paid solution – but wildly popular in mobile devices. There are, of course, even more "enterprise-level" solutions available from 3rd party vendors. The truth is that most of the customers that I work with don't need that level of protection of their digital assets, and something like a KeePass database on Sharepoint suits them very well. What are you doing to safeguard your passwords? Leave a comment below, and join the discussion! Cheers, -Argenis

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  • Perspective Is Everything

    - by juanlarios
    Sitting on a window seat on my way back from Seattle I looked out the window and saw the large body of water. I was reminded of childhood memories of running as hard as I could through burning hot sand with the anticipation of the splash of the ocean. Looking out the window the water appeared like a sheet draped over land. I couldn’t help but ponder how perspective changes everything.  Over the last several days I had a chance to attend the MVP Summit in Redmond. I had a great time with fellow MVP’s and the SharePoint Product Group. Although I can’t say much about what was discussed and what is coming in the future, I want to share some realizations I had while experiencing the MVP summit.  The SharePoint Product is ever-improving, full of innovation but also a reactionary embodiment of MVP, client and market feedback. There are several features that come to mind that clients complain about where I have felt helpless in informing them that the features are not as mature as they would like it. Together, we figure out a way to make it work and deal with the limitations. It became clear that there are features that have taken a different purpose in the market place from the original vision. The SP Product group is working hard to react to these changes in vision and make SharePoint better for real life implementations.  It is easy to think that SharePoint should be all things to all people. In reality there are products that are very detailed in specific composites, they do this one thing well but severely lack in other areas.  Its easy sometimes to say, “What was Microsoft thinking with this feature?” the Product group is doing all they can to make the moving pieces better and dealing with challenges with having all of them work together.  Sometimes the features don’t fully embody the vision because of the many challenges, but trust me when I say the product group is really focused on delivery and innovation.  As I was speaking with a fellow MVP throughout the session, we spoke about the iPad 2(ironically announced this past week during the MVP summit) and Microsoft’s possible product answer; I realized the days of reactionary products from MS is over. There are many users that will remember Vista and the painful execution in that product, but there has been a lot of success in Windows 7. There was no rush for a reactionary answer to the Nintendo Wii, as a result a ground breaking and game changing product was brought to market, the XBOX –Kinect! I can’t say much here, but it’s safe to say, expect innovation, and execution of products and technology that will change the market instead of react to them!       There are many things I learned and I would love to share that have to do with perspective, technology, etc… but this is far as I can go in details. This might not be new to you or specifically the message that was shared during the summit. These are just my impressions of the event and the spirit of future vision. Great things ahead!

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  • CI tests to enforce specific development rules - good practice?

    - by KeithS
    The following is all purely hypothetical and any particular portion of it may or may not accurately describe real persons or situations, whether living, dead or just pretending. Let's say I'm a senior dev or architect in charge of a dev team working on a project. This project includes a security library for user authentication/authorization of the application under development. The library must be available for developers to edit; however, I wish to "trust but verify" that coders are not doing things that could compromise the security of the finished system, and because this isn't my only responsibility I want it to be done in an automated way. As one example, let's say I have an interface that represents a user which has been authenticated by the system's security library. The interface exposes basic user info and a list of things the user is authorized to do (so that the client app doesn't have to keep asking the server "can I do this?"), all in an immutable fashion of course. There is only one implementation of this interface in production code, and for the purposes of this post we can say that all appropriate measures have been taken to ensure that this implementation can only be used by the one part of our code that needs to be able to create concretions of the interface. The coders have been instructed that this interface and its implementation are sacrosanct and any changes must go through me. However, those are just words; the security library's source is open for editing by necessity. Any of my devs could decide that this secured, private, hash-checked implementation needs to be public so that they could do X, or alternately they could create their own implementation of this public interface in a different library, exposing the hashing algorithm that provides the secure checksum, in order to do Y. I may not be made aware of these changes so that I can beat the developer over the head for it. An attacker could then find these little nuggets in an unobfuscated library of the compiled product, and exploit it to provide fake users and/or falsely-elevated administrative permissions, bypassing the entire security system. This possibility keeps me awake for a couple of nights, and then I create an automated test that reflectively checks the codebase for types deriving from the interface, and fails if it finds any that are not exactly what and where I expect them to be. I compile this test into a project under a separate folder of the VCS that only I have rights to commit to, have CI compile it as an external library of the main project, and set it up to run as part of the CI test suite for user commits. Now, I have an automated test under my complete control that will tell me (and everyone else) if the number of implementations increases without my involvement, or an implementation that I did know about has anything new added or has its modifiers or those of its members changed. I can then investigate further, and regain the opportunity to beat developers over the head as necessary. Is this considered "reasonable" to want to do in situations like this? Am I going to be seen in a negative light for going behind my devs' backs to ensure they aren't doing something they shouldn't?

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  • Dependency injection: How to sell it

    - by Mel
    Let it be known that I am a big fan of dependency injection (DI) and automated testing. I could talk all day about it. Background Recently, our team just got this big project that is to built from scratch. It is a strategic application with complex business requirements. Of course, I wanted it to be nice and clean, which for me meant: maintainable and testable. So I wanted to use DI. Resistance The problem was in our team, DI is taboo. It has been brought up a few times, but the gods do not approve. But that did not discourage me. My Move This may sound weird but third-party libraries are usually not approved by our architect team (think: "thou shalt not speak of Unity, Ninject, NHibernate, Moq or NUnit, lest I cut your finger"). So instead of using an established DI container, I wrote an extremely simple container. It basically wired up all your dependencies on startup, injects any dependencies (constructor/property) and disposed any disposable objects at the end of the web request. It was extremely lightweight and just did what we needed. And then I asked them to review it. The Response Well, to make it short. I was met with heavy resistance. The main argument was, "We don't need to add this layer of complexity to an already complex project". Also, "It's not like we will be plugging in different implementations of components". And "We want to keep it simple, if possible just stuff everything into one assembly. DI is an uneeded complexity with no benefit". Finally, My Question How would you handle my situation? I am not good in presenting my ideas, and I would like to know how people would present their argument. Of course, I am assuming that like me, you prefer to use DI. If you don't agree, please do say why so I can see the other side of the coin. It would be really interesting to see the point of view of someone who disagrees. Update Thank you for everyone's answers. It really puts things into perspective. It's nice enough to have another set of eyes to give you feedback, fifteen is really awesome! This are really great answers and helped me see the issue from different sides, but I can only choose one answer, so I will just pick the top voted one. Thanks everyone for taking the time to answer. I have decided that it is probably not the best time to implement DI, and we are not ready for it. Instead, I will concentrate my efforts on making the design testable and attempt to present automated unit testing. I am aware that writing tests is additional overhead and if ever it is decided that the additional overhead is not worth it, personally I would still see it as a win situation since the design is still testable. And if ever testing or DI is a choice in future, the design can easily handle it.

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  • Moving StarterSTS to the (Azure) Cloud

    - by Your DisplayName here!
    Quite some people asked me about an Azure version of StarterSTS. While I kinda knew what I had to do to make the move, I couldn’t find the time. Until recently. This blog post briefly documents the necessary changes and design decisions for the next version of StarterSTS which will work both on-premise and on Azure. Provider Fortunately StarterSTS is already based on the idea of “providers”. Authentication, roles and claims generation is based on the standard ASP.NET provider infrastructure. This makes the migration to different data stores less painful. In my case I simply moved the ASP.NET provider database to SQL Azure and still use the standard SQL Server based membership, roles and profile provider. In addition StarterSTS has its own providers to abstract resource access for certificates, relying party registration, client certificate registration and delegation. So I only had to provide new implementations. Signing and SSL keys now go in the Azure certificate store and user mappings (client certificates and delegation settings) have been moved to Azure table storage. The one thing I didn’t anticipate when I originally wrote StarterSTS was the need to also encapsulate configuration. Currently configuration is “locked” to the standard .NET configuration system. The new version will have a pluggable SettingsProvider with versions for .NET configuration as well as Azure service configuration. If you want to externalize these settings into e.g. a database, it is now just a matter of supplying a corresponding provider. Moving between the on-premise and Azure version will be just a matter of using different providers. URL Handling Another thing that’s substantially different on Azure (and load balanced scenarios in general) is the handling of URLs. In farm scenarios, the standard APIs like ASP.NET’s Request.Url return the current (internal) machine name, but you typically need the address of the external facing load balancer. There’s a hotfix for WCF 3.5 (included in v4) that fixes this for WCF metadata. This was accomplished by using the HTTP Host header to generate URLs instead of the local machine name. I now use the same approach for generating WS-Federation metadata as well as information card files. New Features I introduced a cache provider. Since we now have slightly more expensive lookups (e.g. relying party data from table storage), it makes sense to cache certain data in the front end. The default implementation uses the ASP.NET web cache and can be easily extended to use products like memcached or AppFabric Caching. Starting with the relying party provider, I now also provide a read/write interface. This allows building management interfaces on top of this provider. I also include a (very) simple web page that allows working with the relying party provider data. I guess I will use the same approach for other providers in the future as well. I am also doing some work on the tracing and health monitoring area. Especially important for the Azure version. Stay tuned.

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  • Dependency Injection Introduction

    - by MarkPearl
    I recently was going over a great book called “Dependency Injection in .Net” by Mark Seeman. So far I have really enjoyed the book and would recommend anyone looking to get into DI to give it a read. Today I thought I would blog about the first example Mark gives in his book to illustrate some of the benefits that DI provides. The ones he lists are Late binding Extensibility Parallel Development Maintainability Testability To illustrate some of these benefits he gives a HelloWorld example using DI that illustrates some of the basic principles. It goes something like this… class Program { static void Main(string[] args) { var writer = new ConsoleMessageWriter(); var salutation = new Salutation(writer); salutation.Exclaim(); Console.ReadLine(); } } public interface IMessageWriter { void Write(string message); } public class ConsoleMessageWriter : IMessageWriter { public void Write(string message) { Console.WriteLine(message); } } public class Salutation { private readonly IMessageWriter _writer; public Salutation(IMessageWriter writer) { _writer = writer; } public void Exclaim() { _writer.Write("Hello World"); } }   If you had asked me a few years ago if I had thought this was a good approach to solving the HelloWorld problem I would have resounded “No”. How could the above be better than the following…. class Program { static void Main(string[] args) { Console.WriteLine("Hello World"); Console.ReadLine(); } }  Today, my mind-set has changed because of the pain of past programs. So often we can look at a small snippet of code and make judgements when we need to keep in mind that we will most probably be implementing these patterns in projects with hundreds of thousands of lines of code and in projects that we have tests that we don’t want to break and that’s where the first solution outshines the latter. Let’s see if the first example achieves some of the outcomes that were listed as benefits of DI. Could I test the first solution easily? Yes… We could write something like the following using NUnit and RhinoMocks… [TestFixture] public class SalutationTests { [Test] public void ExclaimWillWriteCorrectMessageToMessageWriter() { var writerMock = MockRepository.GenerateMock<IMessageWriter>(); var sut = new Salutation(writerMock); sut.Exclaim(); writerMock.AssertWasCalled(x => x.Write("Hello World")); } }   This would test the existing code fine. Let’s say we then wanted to extend the original solution so that we had a secure message writer. We could write a class like the following… public class SecureMessageWriter : IMessageWriter { private readonly IMessageWriter _writer; private readonly string _secretPassword; public SecureMessageWriter(IMessageWriter writer, string secretPassword) { _writer = writer; _secretPassword = secretPassword; } public void Write(string message) { if (_secretPassword == "Mark") { _writer.Write(message); } else { _writer.Write("Unauthenticated"); } } }   And then extend our implementation of the program as follows… class Program { static void Main(string[] args) { var writer = new SecureMessageWriter(new ConsoleMessageWriter(), "Mark"); var salutation = new Salutation(writer); salutation.Exclaim(); Console.ReadLine(); } }   Our application has now been successfully extended and yet we did very little code change. In addition, our existing tests did not break and we would just need add tests for the extended functionality. Would this approach allow parallel development? Well, I am in two camps on parallel development but with some planning ahead of time it would allow for it as you would simply need to decide on the interface signature and could then have teams develop different sections programming to that interface. So,this was really just a quick intro to some of the basic concepts of DI that Mark introduces very successfully in his book. I am hoping to blog about this further as I continue through the book to list some of the more complex implementations of containers.

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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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  • Custom Text and Binary Payloads using WebSocket (TOTD #186)

    - by arungupta
    TOTD #185 explained how to process text and binary payloads in a WebSocket endpoint. In summary, a text payload may be received as public void receiveTextMessage(String message) {    . . . } And binary payload may be received as: public void recieveBinaryMessage(ByteBuffer message) {    . . .} As you realize, both of these methods receive the text and binary data in raw format. However you may like to receive and send the data using a POJO. This marshaling and unmarshaling can be done in the method implementation but JSR 356 API provides a cleaner way. For encoding and decoding text payload into POJO, Decoder.Text (for inbound payload) and Encoder.Text (for outbound payload) interfaces need to be implemented. A sample implementation below shows how text payload consisting of JSON structures can be encoded and decoded. public class MyMessage implements Decoder.Text<MyMessage>, Encoder.Text<MyMessage> {     private JsonObject jsonObject;    @Override    public MyMessage decode(String string) throws DecodeException {        this.jsonObject = new JsonReader(new StringReader(string)).readObject();               return this;    }     @Override    public boolean willDecode(String string) {        return true;    }     @Override    public String encode(MyMessage myMessage) throws EncodeException {        return myMessage.jsonObject.toString();    } public JsonObject getObject() { return jsonObject; }} In this implementation, the decode method decodes incoming text payload to MyMessage, the encode method encodes MyMessage for the outgoing text payload, and the willDecode method returns true or false if the message can be decoded. The encoder and decoder implementation classes need to be specified in the WebSocket endpoint as: @WebSocketEndpoint(value="/endpoint", encoders={MyMessage.class}, decoders={MyMessage.class}) public class MyEndpoint { public MyMessage receiveMessage(MyMessage message) { . . . } } Notice the updated method signature where the application is working with MyMessage instead of the raw string. Note that the encoder and decoder implementations just illustrate the point and provide no validation or exception handling. Similarly Encooder.Binary and Decoder.Binary interfaces need to be implemented for encoding and decoding binary payload. Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) TOTD #183 - Getting Started with WebSocket in GlassFish TOTD #184 - Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark TOTD #185: Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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  • Android: Map Overlay Labels

    - by karnage
    I am building a MapView and I want my custom overlay items to display the name of the location they are marking when the user taps them, like the Android Maps app. I setup the onTap listener and the floating TextView to hold the location name. I still need to set it up so that it redraws the label when the user moves the map, etc. Anyway, I am wondering if I am reinventing the wheel here. Is there a built-in method I am unaware of? I would think that most implementations of MapView have labels. For reference, my implementation so far: in map xml: <LinearLayout android:id="@+id/mapBubbleWrap" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true"> <TextView android:id="@+id/mapBubble" android:layout_width="wrap_content" android:layout_height="wrap_content" android:visibility="gone" android:background="#ffffff" android:textColor="#ff0000"/> </LinearLayout> in my extended ItemizedOverlay: public boolean onTap(int index) { this.setFocus( mOverlays.get(index) ); return true; } in my Activity onFocus: public void onFocusChanged( ItemizedOverlay overlay, OverlayItem item ) { if( item != null) { mapBubble.setText(item.getTitle()); Point newPoint = mapView.getProjection().toPixels(item.getPoint(), null); mapBubbleWrap.setPadding(newPoint.x, newPoint.y-10, 0, 0); mapBubble.setVisibility(View.VISIBLE); } }

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  • Server socket programming in Android 1.5, most power efficient way?

    - by Antek
    Hello people, I am doing a project where I have too develop an application that listens for incoming events by a service. The device that has to listen too events is an Android phone with Android SDK 1.5 on it. Currently the services that call events only implement communication trough UDP or TCP sockets. I can solve my problem by setting up a ServerSocket, but i doubt that's the most power efficient way. This application will be running most of the time, with Wi-Fi on, and I'd like too reach an long battery duration. I've been looking for options on the internet for my question for a while but i couldn't get a real answer. I've got the following questions: What is the most efficient way too listen to incoming events? Should I make an ServerSocket? or what are my options? Are there any other implementations that are more power efficient? Ive been also thinking of implementing communication trough XMPP. Not sure if this is the best way. I'm not forced too an specific implementation. All suggestions are welcome! Thanks for the help, Antek

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  • JSON-RPC and Json-rpc service discovery specifications

    - by Artyom
    Hello, I'm going to implement JSON-PRC web service. I need specifications for this. So far I had found only one resource that can be called as real specifications: JSON-RPC 1.0 http://json-rpc.org/wiki/specification Proposal of JSON-PRC 2.0: http://groups.google.com/group/json-rpc/web/json-rpc-2-0 (why is it on google groups?) However I've seen that JavaScript frameworks like Dojo actively use JSON-RPC SMD Service Mapping Description proposal But it requires JSON Schema specifications, but it redirects to incorrect URL as reference. So far I had found following: http://tools.ietf.org/html/draft-zyp-json-schema-02 And it is still draft... Can anybody point me to some actual specifications... At least something official updated? Because it looks like that implementing JSON-RPC 1.0 as is may be not enough, at least for frameworks like Dojo. Or am I wrong? Questions: Would implementation of JSON-RPC 1.0 specifications be enough to provide JSON-RPC service for most of modern clients, and how many clients there (if at-all) that actually support beyond JSON-RPC 1.0 capabilities (SMD, Schema, 2.0)? Because it looks like that JSON-RPC 1.0 is only one that has official specifications (and not draft) If I should implement SMD, or it is recommended can somebody point to official, most recent specifications of Json Schema and Service Mapping Description or links I found are really "the specifications?" Are JSON-RPC 2.0, SMD and JSON-Schema drafts stable enough to implement them? Note: do not suggest existing JSON-RPC service implementations. Anybody?

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  • Full JSON-RPC specifications

    - by Artyom
    Hello, I'm going to implement JSON-PRC web service. I need specifications for this. So far I had found only one resource that can be called as real specifications: JSON-RPC 1.0 http://json-rpc.org/wiki/specification Proposal of JSON-PRC 2.0: http://groups.google.com/group/json-rpc/web/json-rpc-2-0 (why is it on google groups?) However I've seen that JavaScript frameworks like Dojo actively use JSON-RPC SMD Service Mapping Description proposal But it requires JSON Schema specifications, but it redirects to incorrect URL as reference. So far I had found following: http://tools.ietf.org/html/draft-zyp-json-schema-02 And it is still draft... Can anybody point me to spome actual specifications... At least something official updated? Because it looks like that implementing JSON-RPC 1.0 and 2.0 would not be enought, at least for frameworks like Dojo. Or am I wrong? Questions: Is it enough to implement JSON-RPC 1.0 specifications and 2.0 draft to be on safe side, would this work for most JSON-RPC clients? If I should implement SMD, or it is recommended can somebody point to official specifications of Json Schema and Service Mapping Description or links I found are really "specifications?" Note: do not suggest existing JSON-RPC service implementations.

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  • Selection Highlight in NSCollectionView

    - by Hooligancat
    On some occasions my head just hurts from banging it against the Cocoa wall. Today is one of those days. I have a working NSCollectionView with one minor, but critical, exception. Getting and highlighting the selected item within the collection. I've had all this working prior to Snow Leopard, but something appears to have changed and I can't quite place my finger on it, so I took my NSCollectionView right back to a basic test and followed Apple's documentation for creating an NSCollectionView here: http://developer.apple.com/mac/library/DOCUMENTATION/Cocoa/Conceptual/CollectionViews/Introduction/Introduction.html The collection view works fine following the quick start guide. However, this guide doesn't discuss selection other than "There are such features as incorporating image views, setting objects as selectable or not selectable and changing colors if they are selected". Using this as an example I went to the next step of binding the Array Controller to the NSCollectionView with the controller key selectionIndexes, thinking that this would bind any selection I make between the NSCollectionView and the array controller and thus firing off a KVO notification. I also set the NSCollectionView to be selectable in IB. There appears to be no selection delegate for NSCollectionView and unlike most Cocoa UI views, there appears to be no default selected highlight. So my problem really comes down to a related issue, but two distinct questions. How do I capture a selection of an item? How do I show a highlight of an item? NSCollectionView's programming guides seem to be few and far between and most searches via Google appear to pull up pre-Snow Leopard implementations, or use the view in a separate XIB file. For the latter (separate XIB file for the view), I don't see why this should be a pre-requisite otherwise I would have suspected that Apple would not have included the view in the same bundle as the collection view item. I know this is going to be a "can't see the wood for the trees" issue - so I'm prepared for the "doh!" moment. As usual, any and all help much appreciated.

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  • Spring Test / JUnit problem - unable to load application context

    - by HDave
    I am using Spring for the first time and must be doing something wrong. I have a project with several Bean implementations and now I am trying to create a test class with Spring Test and JUnit. I am trying to use Spring Test to inject a customized bean into the test class. Here is my test-applicationContext.xml: <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="............."> <bean id="MyUuidFactory" class="com.myapp.UuidFactory" scope="singleton" > <property name="typeIdentifier" value="CLS" /> </bean> <bean id="ThingyImplTest" class="com.myapp.ThingyImplTest" scope="singleton"> <property name="uuidFactory"> <idref local="MyUuidFactory" /> </property> </bean> </beans> The injection of MyUuidFactory instance goes along with the following code from within the test class: private UuidFactory uuidFactory; public void setUuidFactory(UuidFactory uuidFactory) { this.uuidFactory = uuidFactory; } However, when I go to run the test (in Eclipse or command line) I get the following error (stack trace omitted for brevity): Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'MyImplTest' defined in class path resource [test-applicationContext.xml]: Initialization of bean failed; nested exception is org.springframework.beans.ConversionNotSupportedException: Failed to convert property value of type 'java.lang.String' to required type 'com.myapp.UuidFactory' for property 'uuidFactory'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [com.myapp.UuidFactory] for property 'uuidFactory': no matching editors or conversion strategy found Funny thing is, the Eclipse/Spring XML editor shows errors of I misspell any of the types or idrefs. If I leave the bean in, but comment out the dependency injection, everything work until I get a NullPointerException while running the test...which makes sense.

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  • Ipad MPMovieplayerController video loads but automatically pauses when played

    - by slayerIQ
    Hello I am trying to get the MPMovieplayerController to work. I load a video everything goes wel i even see the first frame but then it automatically pauses, if i press play it pauses again. In the simulator it works perfectly but on the ipad device it gives the problem. I can even seek through the video and i see the frame i seeked to but nothing plays. This is some output from the console: 2010-06-08 22:16:13.145 app[3089:207] Using two-stage rotation animation. To use the smoother single-stage animation, this application must remove two-stage method implementations. [Switching to thread 12803] warning: Unable to read symbols for "/Developer/Platforms/iPhoneOS.platform/DeviceSupport/3.2 (7B367)/Symbols/System/Library/VideoDecoders/VCH263.videodecoder" (file not found). warning: Unable to read symbols for "/Developer/Platforms/iPhoneOS.platform/DeviceSupport/3.2 (7B367)/Symbols/System/Library/VideoDecoders/H264H2.videodecoder" (file not found). warning: Unable to read symbols for "/Developer/Platforms/iPhoneOS.platform/DeviceSupport/3.2 (7B367)/Symbols/System/Library/VideoDecoders/MP4VH2.videodecoder" (file not found). warning: Unable to read symbols for "/Developer/Platforms/iPhoneOS.platform/DeviceSupport/3.2 (7B367)/Symbols/System/Library/VideoDecoders/JPEGH1.videodecoder" (file not found). 2010-06-08 22:16:15.145 app[3089:207] setting file:///private/var/mobile/Applications/46CE5456-6338-4BBF-A560-DCEFF700ACE0/tmp/MediaCache/ I dont get those warning when using the simulator BTW. Does anyone know how to fix this ?

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  • C# Thread Pool Cross-Thread Communication

    - by Goober
    The Scenario I have a windows forms application containing a MAINFORM with a listbox on it. The MAINFORM also has a THREAD POOL that creates new threads and fires them off to do lots of different bits of processing. Whilst each of these different worker threads is doing its job, I want to report this progress back to my MAINFORM, however, I can't because it requires Cross-Thread communication. Progress So far all of the tutorials etc. that I have seen relating to this topic involve custom(ish) threading implementations, whereas I literally have a fairly basic(ish) standard THREAD POOL implementation. Since I don't want to really modify any of my code (since the application runs like a beast with no quarms) - I'm after some advice as to how I can go about doing this cross-thread communication. ALTERNATIVELY - How to implement a different "LOGTOSCREEN" method altogether (obviously still bearing in mind the cross-thread communication thing). WARNING: I use this website at work, where we are locked down to IE6 only, and the javascript thus fails, meaning I cannot click accept on any answers during work, and thus my acceptance rate is low. I can't do anything about it I'm afraid, sorry. EDIT: I DO NOT HAVE INSTALL RIGHTS ON MY COMPUTER AT WORK. I do have firefox but the proxy at work fails when using this site on firefox. FURTHER EDIT: I DO NOT WANT TO CHANGE MY THREADING IMPLEMENTATION. AT ALL! - Accept to enable cross-thread communication....why would a backgroundworker help here!?

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