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• Video works with 'Try me' but not after install. What is the difference? U12.04LTS,

  - by HarveyP

  My hard drive got corrupted so I did a reinstall. Tested Youtube in FF during 'try me' and it worked - jerky, but it worked. Instal without all the updates (576 outstanding now) in order to get ff installed as per the demo - to no avail. In 'try me' mode ff NEVER crashed! After install ff crashed whilst I was typing in 'youtube' in the address field. When I finally got to youtube - no video. What is the difference between ff in try me and ff after install? Off to try some selected updates now to see if I can see it for myself. In previous installation I had several profiles and aliased ff with -safe-mode switch to simplify startup of most stable ff. Also found that ff startup in graphic mode worked better (but still without video) with all of the extensions disabled and all of the plugins set to "ask" and always denied ... I have SiS graphic card in SiS Motherboard for XP and ancient Hyundai ImageQuest QV770 monitor. I have Ubuntu 12.04.01 LTS 1 day after install with only the immediate upgrades requested to language pack (English UK). Using FR Alternative keyboard. Connected with domestic wifi network from Orange (FT) I really want to use Skype, but won't bother installing it (again) without video as I can do my sms on FB - whilst ff is not crashed ... Update ... Is something overflowing? I have just had to reboot in order to get ff to restart in any way shape or form - restart on crash form generates new crash form, etc. It was however a good half hour before it crashed so some improvement over conditions before disk corruption. I have now installed all of the critical updates (332 recommended updates still outstanding) which included some relating to ff. Still no video. Still crashing - especially when on Grepolis website. Since the re-install I have had a lovely 1024x768 screen, but after last ff crash and reboot I got a message about 'low graphics mode' and 'setting things myself'. I was not sufficiently tuned in at the time to take proper note - I have no doubt I shall see it again and shall report accordingly. I still have only laptop options for my screen and do not know how to rectify this. Spent a few days with ubuntu on a different, newer machine which has now suffered a graphics breakdown. Returned to this old one again, but with new flat screen Monitor. Found SIS drivers for my graphics BUT it is intended for Red Hat 7.2. I chose this over the version for 7.0 because I thought what the hell, I might not be able to do anything with either of them but this is the later one ... The file will not open with software manager - found a similar problem on Overclock but it has not helped me to install this driver. File name is sis_drv.o-410 and it is currently idling away in my Downloads folder ... I have tried the solution offered on another sis problem, but this shows that my xserver-xorg-video-sis driver is up to date. I am now at a loss as to how to proceed if I can't install the latest sis driver from sis ... Does nobody know how FF changes from "try-me" to "installed"? Any time I MUST have video I reboot from the disk again, but this is tedious! Also one of the things I mock most about MS is the constant rebooting ... UPDATE 10/6/2014 I have installed chromium-browser - worse, crashes even more often than ff.I have installed epiphany - better; Video works but not the associated soundtrack.FireFox is version 14.01 in 'try me' and version 29.0 from my install. Would it be useful to try to downgrade FireFox in order to get video?

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• Html.ValidationSummary and Multiple Forms

  - by MightyZot

  Originally posted on: http://geekswithblogs.net/MightyZot/archive/2013/11/11/html.validationsummary-and-multiple-forms.aspxThe Html.ValidationSummary helper writes a div with a list of general errors added to the model state while a request is being serviced. There is generally one form per view or partial view, I think, so often there is only one call to Html.ValidationSummary in the page resulting from the assembly of your views. And, consequently, there is no problem with the markup that Html.ValidationSummary spits out as a result. What if you want to put multiple forms in one view? Even if you create a view model that’s an aggregate of the view models for each form, the error validation summary is going to contain errors from both forms. Check out this screen shot, which shows a page with multiple forms. Notice how the error validation summary shows up twice. Grrr! Errors for the login form also show up in the registration form. Luckily, there is an easy way around this. Pull the errors out of the model state and separate them for each form. You’ll need to identify the appropriate form by setting the key when you make calls to ModelState.AddModelError. Assume in my example that errors for the login form are added to model state using the “LoginForm” key. And, likewise, assume that errors for the registration form are added to model state using the “RegistrationForm” key. An example of that might look like this… // If we got this far, something failed, redisplay form ModelState.AddModelError("LoginForm", "User name or password is not right..."); return View(model); Over in the code for your View, you can pull each form’s errors from the model state using lambda expressions that look like these… var LoginFormErrors = ViewData.ModelState.Where(ms => ms.Key == "LoginForm"); var RegistrationFormErrors = ViewData.ModelState.Where(ms => ms.Key == "RegistrationForm"); Now that you have two collections containing errors, you can display only the errors specific to each form. I’m doing that in my code by removing the calls to Html.ValidationSummary and replacing them with enumerators that look like this… if(LoginFormErrors.Count() > 0) { <div class="cdt-error-list">     <ul>     @foreach (var entry in LoginFormErrors)     {         foreach (var error in entry.Value.Errors)         {             <li>@error.ErrorMessage</li>         }     }     </ul> </div> } …and for the registration form, the code looks like this… @if(RegistrationFormErrors.Count() > 0) { <div class="cdt-error-list">     <ul>     @foreach (var entry in RegistrationFormErrors)     {         foreach (var error in entry.Value.Errors)         {             <li>@error.ErrorMessage</li>         }     }     </ul> </div> } The result is a nice clean separation of the list of errors that are specific to each form. And, this is important because each form is submitted separately in my case, so both forms don’t generate errors in the same context. As you’ll see in the screen shot below, errors added to the model state when the login form is submitted do not show up in the registration form’s validation summary.

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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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• When things go awry

  - by Phil Factor

  The moment the Entrepreneur opened his mouth on prime-time national TV, spelled out the URL and waxed big on how exciting ‘his’ new website was, I knew I was in for a busy night. I’d designed and built it. All at once, half a million people tried to log into the website. Although all my stress-testing paid off, I have to admit that the network locked up tight long before there was any danger of a database or website problem. Soon afterwards, the Entrepreneur and the Big Boss were there in the autopsy meeting. We picked through all our systems in detail to see how they’d borne the unexpected strain. Mercifully, in view of the sour mood of the Big Boss, it turned out that the only thing we could have done better was buy a bigger pipe to and from the internet. We’d specified that ‘big pipe’ when designing the system. The Big Boss had then railed at the cost and so we’d subsequently compromised. I felt that my design decisions were vindicated. The Big Boss brooded for a while. Then he made the significant comment: “What really ****** me off is the fact that, for ten minutes, we couldn’t take people’s money.” At that point I stopped feeling smug. Had the internet connection been better, the system would have reached its limit and failed rather precipitously, and that wasn’t what he wanted. Then it occurred to me that what had gummed up the connection was all those images on the site, that had made it so impressive for the visitors. If there had been a way to automatically pare down the site to the bare essentials under stress… Hmm. I began to consider disaster-recovery in the broadest sense – maintaining a service in spite of unusual or unexpected events. What he said makes a lot of sense: sacrifice whatever isn’t essential to keep the core service running when we approach the capacity limits. Maybe in IT we should borrow (or revive) the business concept of the ‘Skeleton service’, maintaining only the priority parts under stress, using a process that is well-prepared and carefully rehearsed. How might this work? Whatever the event we have to prepare for, it is all about understanding the priorities; knowing what one can dispense with when the going gets tough. In the event of database disaster, it’s much faster to deploy a skeletal system with only the essential data than to restore the entire system, though there would have to be a reconciliation process to update the revived database retrospectively, once the emergency was over. It isn’t just the database that could be designed for resilience. One could prepare for unusually high traffic in a website by designing a system that degraded gradually to a ‘skeletal’ site, one that maintained the commercial essentials without fat images, JavaScript libraries and razzmatazz. This is all what the Big Boss scathingly called ‘a mere technicality’. It seems to me that what is needed first is a culture of application and database design which acknowledges that we live in a very imperfect world, and react accordingly when things go awry.

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• Data breakpoints to find points where data gets broken

  - by raccoon_tim

  When working with a large code base, finding reasons for bizarre bugs can often be like finding a needle in a hay stack. Finding out why an object gets corrupted without no apparent reason can be quite daunting, especially when it seems to happen randomly and totally out of context. Scenario Take the following scenario as an example. You have defined the a class that contains an array of characters that is 256 characters long. You now implement a method for filling this buffer with a string passed as an argument. At this point you mistakenly expect the buffer to be 256 characters long. At some point you notice that you require another character buffer and you add that after the previous one in the class definition. You now figure that you don’t need the 256 characters that the first member can hold and you shorten that to 128 to conserve space. At this point you should start thinking that you also have to modify the method defined above to safeguard against buffer overflow. It so happens, however, that in this not so perfect world this does not cross your mind. Buffer overflow is one of the most frequent sources for errors in a piece of software and often one of the most difficult ones to detect, especially when data is read from an outside source. Many mass copy functions provided by the C run-time provide versions that have boundary checking (defined with the _s suffix) but they can not guard against hard coded buffer lengths that at some point get changed. Finding the bug Getting back to the scenario, you’re now wondering why does the second string get modified with data that makes no sense at all. Luckily, Visual Studio provides you with a tool to help you with finding just these kinds of errors. It’s called data breakpoints. To add a data breakpoint, you first run your application in debug mode or attach to it in the usual way, and then go to Debug, select New Breakpoint and New Data Breakpoint. In the popup that opens, you can type in the memory address and the amount of bytes you wish to monitor. You can also use an expression here, but it’s often difficult to come up with an expression for data in an object allocated on the heap when not in the context of a certain stack frame. There are a couple of things to note about data breakpoints, however. First of all, Visual Studio supports a maximum of four data breakpoints at any given time. Another important thing to notice is that some C run-time functions modify memory in kernel space which does not trigger the data breakpoint. For instance, calling ReadFile on a buffer that is monitored by a data breakpoint will not trigger the breakpoint. The application will now break at the address you specified it to. Often you might immediately spot the issue but the very least this feature can do is point you in the right direction in search for the real reason why the memory gets inadvertently modified. Conclusions Data breakpoints are a great feature, especially when doing a lot of low level operations where multiple locations modify the same data. With the exception of some special cases, like kernel memory modification, you can use it whenever you need to check when memory at a certain location gets changed on purpose or inadvertently.

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• Resolving collisions between dynamic game objects

  - by TheBroodian

  I've been building a 2D platformer for some time now, I'm getting to the point where I am adding dynamic objects to the stage for testing. This has prompted me to consider how I would like my character and other objects to behave when they collide. A typical staple in many 2D platformer type games is that the player takes damage upon touching an enemy, and then essentially becomes able to pass through enemies during a period of invulnerability, and at the same time, enemies are able to pass through eachother freely. I personally don't want to take this approach, it feels strange to me that the player should receive arbitrary damage for harmless contact to an enemy, despite whether the enemy is attacking or not, and I would like my enemies' interactions between each other (and my player) to be a little more organic, so to speak. In my head I sort of have this idea where a game object (player, or non player) would be able to push other game objects around by manner of 'pushing' each other out of one anothers' bounding boxes if there is an intersection, and maybe correlate the repelling force to how much their bounding boxes are intersecting. The problem I'm experiencing is I have no idea what the math might look like for something like this? I'll show what work I've done so far, it sort of works, but it's jittery, and generally not quite what I would pass in a functional game: //Clears the anti-duplicate buffer collisionRecord.Clear(); //pick a thing foreach (GameObject entity in entities) { //pick another thing foreach (GameObject subject in entities) { //check to make sure both things aren't the same thing if (!ReferenceEquals(entity, subject)) { //check to see if thing2 is in semi-near proximity to thing1 if (entity.WideProximityArea.Intersects(subject.CollisionRectangle) || entity.WideProximityArea.Contains(subject.CollisionRectangle)) { //check to see if thing2 and thing1 are colliding. if (entity.CollisionRectangle.Intersects(subject.CollisionRectangle) || entity.CollisionRectangle.Contains(subject.CollisionRectangle) || subject.CollisionRectangle.Contains(entity.CollisionRectangle)) { //check if we've already resolved their collision or not. if (!collisionRecord.ContainsKey(entity.GetHashCode())) { //more duplicate resolution checking. if (!collisionRecord.ContainsKey(subject.GetHashCode())) { //if thing1 is traveling right... if (entity.Velocity.X > 0) { //if it isn't too far to the right... if (subject.CollisionRectangle.Contains(new Microsoft.Xna.Framework.Rectangle(entity.CollisionRectangle.Right, entity.CollisionRectangle.Y, 1, entity.CollisionRectangle.Height)) || subject.CollisionRectangle.Intersects(new Microsoft.Xna.Framework.Rectangle(entity.CollisionRectangle.Right, entity.CollisionRectangle.Y, 1, entity.CollisionRectangle.Height))) { //Find how deep thing1 is intersecting thing2's collision box; float offset = entity.CollisionRectangle.Right - subject.CollisionRectangle.Left; //Move both things in opposite directions half the length of the intersection, pushing thing1 to the left, and thing2 to the right. entity.Velocities.Add(new Vector2(-(((offset * 4) * (float)gameTime.ElapsedGameTime.TotalMilliseconds)), 0)); subject.Velocities.Add(new Vector2((((offset * 4) * (float)gameTime.ElapsedGameTime.TotalMilliseconds)), 0)); } } //if thing1 is traveling left... if (entity.Velocity.X < 0) { //if thing1 isn't too far left... if (entity.CollisionRectangle.Contains(new Microsoft.Xna.Framework.Rectangle(subject.CollisionRectangle.Right, subject.CollisionRectangle.Y, 1, subject.CollisionRectangle.Height)) || entity.CollisionRectangle.Intersects(new Microsoft.Xna.Framework.Rectangle(subject.CollisionRectangle.Right, subject.CollisionRectangle.Y, 1, subject.CollisionRectangle.Height))) { //Find how deep thing1 is intersecting thing2's collision box; float offset = subject.CollisionRectangle.Right - entity.CollisionRectangle.Left; //Move both things in opposite directions half the length of the intersection, pushing thing1 to the right, and thing2 to the left. entity.Velocities.Add(new Vector2((((offset * 4) * (float)gameTime.ElapsedGameTime.TotalMilliseconds)), 0)); subject.Velocities.Add(new Vector2(-(((offset * 4) * (float)gameTime.ElapsedGameTime.TotalMilliseconds)), 0)); } } //Make record that thing1 and thing2 have interacted and the collision has been solved, so that if thing2 is picked next in the foreach loop, it isn't checked against thing1 a second time before the next update. collisionRecord.Add(entity.GetHashCode(), subject.GetHashCode()); } } } } } } } } One of the biggest issues with my code aside from the jitteriness is that if one character were to land on top of another character, it very suddenly and abruptly resolves the collision, whereas I would like a more subtle and gradual resolution. Any thoughts or ideas are incredibly welcome and helpful.

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• When will EBS 12.2 be released?

  - by Steven Chan (Oracle Development)

  The most frequently asked question at OpenWorld this year was, "When will EBS 12.2 be released?" Sadly, Oracle's communication policies prohibit us from speculating about release dates for unreleased software. We are not permitted to give estimates, rough timelines, guesses, or anything else that remotely resembles specific guidance on release dates. You can monitor My Oracle Support and this blog for updates on EBS 12.2.  I'll post them here as soon as they're available.  I'm embedding an old favourite from 2007 in its entirety here, since it applies equally to new releases as well as certifications. "Loose Lips Sink Ships" (March 20, 2007)If I were to sort emails in my inbox into groups, the biggest -- by far -- would be the one for emails that start with, "When will _____ be certified with the E-Business Suite?"  I answer these dutifully but know that my replies can sometimes be maddening, for two reasons:  technical uncertainty, and Oracle's rules for such communications. On the Spiral Model of CertificationsTechnology stack certifications tend to be highly iterative in nature.  As a result, statements about certification dates tend to be accurate only when made in hindsight.  Laypeople are horrified to hear this, but it's the ugly truth.  Uncertainty is simply inherent to the process.  I've become inured to it over the years, but it might come as a surprise to you that it can take many cycles to get fully-released software to work together.  Take this scenario: We test a particular combination of Component A and B. If we encounter a problem, say, with Component A, we log a bug. We receive a new version of Component A. The process iterates again. The reality is this: until a certification is completed and released, there's no accurate way of telling how many iterations are yet to come.  This is true regardless of the number of iterations that have already been completed.  Our Lips Are SealedGenerally, people understand that things are subject to change, so the second reason I can't say anything specific is actually much more important than the first.  "Loose lips might sink ships" was coined in World War II in an effort to remind people that careless talk can have serious consequences.  Curiously, this applies to Oracle's communications about upcoming features, configurations, and releases, too.  As a publicly traded company, we have very strict policies that prohibit us from linking specific releases to specific dates.  If you've ever listened to an earnings call with analysts, you'll often hear them asking, "Can you add a little more color to that statement?"  For certifications, color is usually the only thing that I have.  Sometimes I can provide a bit more information about the technical nature of the certification in question, such as expected footprints or version levels.  I can occasionally share technical issues that we've found, too, to convey the degree of risk or complexity involved in the certification.  Aside from that, there's little additional information about specific dates, date ranges, or even speculation about dates that I can provide... that is, without having one of those uncomfortable conversations with Oracle Legal.  So, as much as it pains me to do so, when it comes to dates, I'm always forced to conclude with a generic reply that blandly states one of the following: We're working on that certification right now That certification is in the pipeline but hasn't been started yet We don't have plans for that certification Don't Shoot the MessengerThankfully, I've developed a thick skin over the years -- which is a good thing, considering the colorful and energetic responses I've received over the years after answering these questions.  However, on behalf of my Oracle colleagues who are faced with these questions every day in the field, I urge you to remember that they're required to follow these same corporate rules about date disclosures.  It never hurts to ask, but don't be too disappointed if we can't provide you with a detailed answer.  The Go-Go's had it right, after all.  Related Articles Webcast Replay Available: Technical Preview of EBS 12.2 Online Patching

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• Collision 2D Quads

  - by Vico Pelaez

  I want to detect collision between two 2D squares, one square is static and the other one moves according to keyboard arrows. I have implemented some code, however nothing happens when they overlap each other and what I tried to achieve in the code was to detect an overlapping between them. I think I am either not understanding the concept really well or that because one of the squares is moving this is not working. Please I would really appreciate your help. Thank you! float x1=0.05 ,Y1=0.05; float x2=0.05 ,Y2=0.05; float posX1 =0.5, posY1 = 0.5; float movX2 = 0.0 , movY2 = 0.0; struct box{ int width=0.1; int heigth=0.1; }; void init(){ glClearColor(0.0, 0.0, 0.0, 0.0); glColor3f(1.0, 1.0, 1.0); } void quad1(){ glTranslatef(posX1, posY1, 0.0); glBegin(GL_POLYGON); glColor3f(0.5, 1.0, 0.5); glVertex2f(-x1, -Y1); glVertex2f(-x1, Y1); glVertex2f(x1,Y1); glVertex2f(x1,-Y1); glEnd(); } void quad2(){ glMatrixMode(GL_PROJECTION); glLoadIdentity(); glPushMatrix(); glTranslatef(movX2, movY2, 0.0); glBegin(GL_POLYGON); glColor3f(1.5, 1.0, 0.5); glVertex2f(-x2, -Y2); glVertex2f(-x2, Y2); glVertex2f(x2,Y2); glVertex2f(x2,-Y2); glEnd(); glPopMatrix(); } void reset(){ //Reset position of square??? movX2 = 0.0; movY2 = 0.0; collisionB = false; } bool collision(box A, box B){ int leftA, leftB; int rightA, rightB; int topA, topB; int bottomA, bottomB; //Calculate the sides of box A leftA = x1; rightA = x1 + A.width; topA = Y1; bottomA = Y1 + A.heigth; //Calculate the sides of box B leftB = x2; rightB = x2 + B.width; topB = Y1; bottomB = Y1+ B.heigth ; if( bottomA <= topB ) return false; if( topA >= bottomB ) return false; if( rightA <= leftB ) return false; if( leftA >= rightB ) return false; return true; } float move_unit = 0.1; void keyboardown(int key, int x, int y) { switch (key){ case GLUT_KEY_UP: movY2 += move_unit; break; case GLUT_KEY_RIGHT: movX2 += move_unit; break; case GLUT_KEY_LEFT: movX2 -= move_unit; break; case GLUT_KEY_DOWN: movY2 -= move_unit; break; default: break; } glutPostRedisplay(); } void display(){ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadIdentity(); cuad1(); if (!collision) { cuad2(); } else{ reset(); } glFlush(); } int main(int argc, char** argv){ glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(500,500); glutInitWindowPosition(0, 0); glutCreateWindow("Collision Practice"); glutSpecialFunc(keyboardown); glutDisplayFunc(display); init(); glutMainLoop(); }

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• Access Control Lists for Roles

  - by Kyle Hatlestad

  Back in an earlier post, I wrote about how to enable entity security (access control lists, aka ACLs) for UCM 11g PS3.  Well, there was actually an additional security option that was included in that release but not fully supported yet (only for Fusion Applications).  It's the ability to define Roles as ACLs to entities (documents and folders).  But now in PS5, this security option is now fully supported.   The benefit of defining Roles for ACLs is that those user roles come from the enterprise security directory (e.g. OID, Active Directory, etc) and thus the WebCenter Content administrator does not need to define them like they do with ACL Groups (Aliases).  So it's a bit of best of both worlds.  Users are managed through the LDAP repository and are automatically granted/denied access through their group membership which are mapped to Roles in WCC.  A different way to think about it is being able to add multiple Accounts to content items...which I often get asked about.  Because LDAP groups can map to Accounts, there has always been this association between the LDAP groups and access to the entity in WCC.  But that mapping had to define the specific level of access (RWDA) and you could only apply one Account per content item or folder.  With Roles for ACLs, it basically takes away both of those restrictions by allowing users to define more then one Role and define the level of access on-the-fly. To turn on ACLs for Roles, there is a component to enable.  On the Component Manager page, click the 'advanced component manager' link in the description paragraph at the top.   In the list of Disabled Components, enable the RoleEntityACL component. Then restart.  This is assuming the other configuration settings have been made for the other ACLs in the earlier post.   Once enabled, a new metadata field called xClbraRoleList will be created.  If you are using OracleTextSearch as the search indexer, be sure to run a Fast Rebuild on the collection. For Users and Groups, these values are automatically picked up from the corresponding database tables.  In the case of Roles, there is an explicitly defined list of choices that are made available.  These values must match the roles that are coming from the enterprise security repository. To add these values, go to Administration -> Admin Applets -> Configuration Manager.  On the Views tab, edit the values for the ExternalRolesView.  By default, 'guest' and 'authenticated' are added.  Once added, you can assign the roles to your content or folder. If you are a user that can both access the Security Group for that item and you belong to that particular Role, you now have access to that item.  If you don't belong to that Role, you won't! [Extra] Because the selection mechanism for the list is using a type-ahead field, users may not even know the possible choices to start typing to.  To help them, one thing you can add to the form is a placeholder field which offers the entire list of roles as an option list they can scroll through (assuming its a manageable size)  and view to know what to type to.  By being a placeholder field, it won't need to be added to the custom metadata database table or search engine.  

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• College Ratings via the Federal Government

  - by user9147039

  A few weeks back you might remember news about a higher education rating system proposal from the Obama administration. As I've discussed previously, political and stakeholder pressures to improve outcomes and increase transparency are stronger than ever before. The executive branch proposal is intended to make progress in this area. Quoting from the proposal itself, "The ratings will be based upon such measures as: Access, such as percentage of students receiving Pell grants; Affordability, such as average tuition, scholarships, and loan debt; and Outcomes, such as graduation and transfer rates, graduate earnings, and advanced degrees of college graduates.” This is going to be quite complex, to say the least. Most notably, higher ed is not monolithic. From community and other 2-year colleges, to small private 4-year, to professional schools, to large public research institutions…the many walks of higher ed life are, well, many. Designing a ratings system that doesn't wind up with lots of unintended consequences and collateral damage will be difficult. At best you would end up potentially tarnishing the reputation of certain institutions that were actually performing well against the metrics and outcome measures that make sense in their "context" of education. At worst you could spend a lot of time and resources designing a system that would lose credibility with its "customers". A lot of institutions I work with already have in place systems like the one described above. They are tracking completion rates, completion timeframes, transfers to other institutions, job placement, and salary information. As I talk to these institutions there are several constants worth noting: • Deciding on which metrics to measure is complicated. While employment and salary data are relatively easy to track, qualitative measures are more difficult. How do you quantify the benefit to someone who studies in one field that may not compensate him or her as well as another field but that provides huge personal fulfillment and reward is a difficult measure to quantify? • The data is available but the systems to transform the data into actual information that can be used in meaningful ways are not. Too often in higher ed information is siloed. As such, much of the data that need to be a part of a comprehensive system sit in multiple organizations, oftentimes outside the reach of core IT. • Politics and culture are big barriers. One of the areas that my team and I spend a lot of time talking about with higher ed institutions all over the world is the imperative to optimize for student success. This, like the tracking of the students’ achievement after graduation, requires a level or organizational capacity that does not currently exist. The primary barrier is the culture of "data islands" in higher ed, and the need for leadership to drive out the divisions between departments, schools, colleges, etc. and institute academy-wide analytics and data stewardship initiatives that will enable student success. • Data quality is a very big issue. So many disparate systems exist (some on premise, some "in the cloud") that keep data about "persons" using different means to identify them. Establishing a single source of truth about an individual and his or her data is difficult without some type of data quality policy and tools. Good tools actually exist but are seldom leveraged. Don't misunderstand - I think it's a great idea to drive additional transparency and accountability into the system of higher education. And not just at home, but globally. Students and parents need access to key data to make informed, responsible choices. The tools exist to not only enable this kind of information to be shared but to capture the very metrics stakeholders care most about and in a way that makes sense in the context of a given institution's "place" in the overall higher ed panoply.

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• Broken Views

  - by Ajarn Mark Caldwell

  “SELECT *” isn’t just hazardous to performance, it can actually return blatantly wrong information. There are a number of blog posts and articles out there that actively discourage the use of the SELECT * FROM …syntax.  The two most common explanations that I have seen are: Performance:  The SELECT * syntax will return every column in the table, but frequently you really only need a few of the columns, and so by using SELECT * your are retrieving large volumes of data that you don’t need, but the system has to process, marshal across tiers, and so on.  It would be much more efficient to only select the specific columns that you need. Future-proof:  If you are taking other shortcuts in your code, along with using SELECT *, you are setting yourself up for trouble down the road when enhancements are made to the system.  For example, if you use SELECT * to return results from a table into a DataTable in .NET, and then reference columns positionally (e.g. myDataRow[5]) you could end up with bad data if someone happens to add a column into position 3 and skewing all the remaining columns’ ordinal position.  Or if you use INSERT…SELECT * then you will likely run into errors when a new column is added to the source table in any position. And if you use SELECT * in the definition of a view, you will run into a variation of the future-proof problem mentioned above.  One of the guys on my team, Mike Byther, ran across this in a project we were doing, but fortunately he caught it while we were still in development.  I asked him to put together a test to prove that this was related to the use of SELECT * and not some other anomaly.  I’ll walk you through the test script so you can see for yourself what happens. We are going to create a table and two views that are based on that table, one of them uses SELECT * and the other explicitly lists the column names.  The script to create these objects is listed below. IF OBJECT_ID('testtab') IS NOT NULL DROP TABLE testtabgoIF OBJECT_ID('testtab_vw') IS NOT NULL DROP VIEW testtab_vwgo IF OBJECT_ID('testtab_vw_named') IS NOT NULL DROP VIEW testtab_vw_namedgo CREATE TABLE testtab (col1 NVARCHAR(5) null, col2 NVARCHAR(5) null)INSERT INTO testtab(col1, col2)VALUES ('A','B'), ('A','B')GOCREATE VIEW testtab_vw AS SELECT * FROM testtabGOCREATE VIEW testtab_vw_named AS SELECT col1, col2 FROM testtabgo Now, to prove that the two views currently return equivalent results, select from them. SELECT 'star', col1, col2 FROM testtab_vwSELECT 'named', col1, col2 FROM testtab_vw_named OK, so far, so good.  Now, what happens if someone makes a change to the definition of the underlying table, and that change results in a new column being inserted between the two existing columns?  (Side note, I normally prefer to append new columns to the end of the table definition, but some people like to keep their columns alphabetized, and for clarity for later people reviewing the schema, it may make sense to group certain columns together.  Whatever the reason, it sometimes happens, and you need to protect yourself and your code from the repercussions.) DROP TABLE testtabgoCREATE TABLE testtab (col1 NVARCHAR(5) null, col3 NVARCHAR(5) NULL, col2 NVARCHAR(5) null)INSERT INTO testtab(col1, col3, col2)VALUES ('A','C','B'), ('A','C','B')goSELECT 'star', col1, col2 FROM testtab_vwSELECT 'named', col1, col2 FROM testtab_vw_named I would have expected that the view using SELECT * in its definition would essentially pass-through the column name and still retrieve the correct data, but that is not what happens.  When you run our two select statements again, you see that the View that is based on SELECT * actually retrieves the data based on the ordinal position of the columns at the time that the view was created.  Sure, one work-around is to recreate the View, but you can’t really count on other developers to know the dependencies you have built-in, and they won’t necessarily recreate the view when they refactor the table. I am sure that there are reasons and justifications for why Views behave this way, but I find it particularly disturbing that you can have code asking for col2, but actually be receiving data from col3.  By the way, for the record, this entire scenario and accompanying test script apply to SQL Server 2008 R2 with Service Pack 1. So, let the developer beware…know what assumptions are in effect around your code, and keep on discouraging people from using SELECT * syntax in anything but the simplest of ad-hoc queries. And of course, let’s clean up after ourselves.  To eliminate the database objects created during this test, run the following commands. DROP TABLE testtabDROP VIEW testtab_vwDROP VIEW testtab_vw_named

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• Criminals and Other Illegal Characters

  - by Most Valuable Yak (Rob Volk)

  SQLTeam's favorite Slovenian blogger Mladen (b | t) had an interesting question on Twitter: http://www.twitter.com/MladenPrajdic/status/347057950470307841 I liked Kendal Van Dyke's (b | t) reply: http://twitter.com/SQLDBA/status/347058908801667072 And he was right!  This is one of those pretty-useless-but-sounds-interesting propositions that I've based all my presentations on, and most of my blog posts. If you read all the replies you'll see a lot of good suggestions.  I particularly like Aaron Bertrand's (b | t) idea of going into the Unicode character set, since there are over 65,000 characters available.  But how to find an illegal character?  Detective work? I'm working on the premise that if SQL Server will reject it as a name it would throw an error.  So all we have to do is generate all Unicode characters, rename a database with that character, and catch any errors. It turns out that dynamic SQL can lend a hand here: IF DB_ID(N'a') IS NULL CREATE DATABASE [a]; DECLARE @c INT=1, @sql NVARCHAR(MAX)=N'', @err NVARCHAR(MAX)=N''; WHILE @c<65536 BEGIN BEGIN TRY SET @sql=N'alter database ' + QUOTENAME(CASE WHEN @c=1 THEN N'a' ELSE NCHAR(@c-1) END) + N' modify name=' + QUOTENAME(NCHAR(@c)); RAISERROR(N'*** Trying %d',10,1,@c) WITH NOWAIT; EXEC(@sql); SET @c+=1; END TRY BEGIN CATCH SET @err=ERROR_MESSAGE(); RAISERROR(N'Ooops - %d - %s',10,1,@c,@err) WITH NOWAIT; BREAK; END CATCH END SET @sql=N'alter database ' + QUOTENAME(NCHAR(@c-1)) + N' modify name=[a]'; EXEC(@sql); The script creates a dummy database "a" if it doesn't already exist, and only tests single characters as a database name.  If you have databases with single character names then you shouldn't run this on that server. It takes a few minutes to run, but if you do you'll see that no errors are thrown for any of the characters.  It seems that SQL Server will accept any character, no matter where they're from.  (Well, there's one, but I won't tell you which. Actually there's 2, but one of them requires some deep existential thinking.) The output is also interesting, as quite a few codes do some weird things there.  I'm pretty sure it's due to the font used in SSMS for the messages output window, not all characters are available.  If you run it using the SQLCMD utility, and use the -o switch to output to a file, and -u for Unicode output, you can open the file in Notepad or another text editor and see the whole thing. I'm not sure what character I'd recommend to answer Mladen's question.  I think the standard tab (ASCII 9) is fine.  There's also several specific separator characters in the original ASCII character set (decimal 28-31). But of all the choices available in Unicode whitespace, I think my favorite would be the Mongolian Vowel Separator.  Or maybe the zero-width space. (that'll be fun to print!)  And since this is Mladen we're talking about, here's a good selection of "intriguing" characters he could use.

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• XNA WP7 Texture memory and ContentManager

  - by jlongstreet

  I'm trying to get my WP7 XNA game's memory under control and under the 90MB limit for submission. One target I identified was UI textures, especially fullscreen ones, that would never get unloaded. So I moved UI texture loads to their own ContentManager so I can unload them. However, this doesn't seem to affect the value of Microsoft.Phone.Info.DeviceExtendedProperties.GetValue("ApplicationCurrentMemoryUsage"), so it doesn't look like the memory is actually being released. Example: splash screens. In Game.LoadContent(): Application.Instance.SetContentManager("UI"); // set the current content manager for (int i = 0; i < mSplashTextures.Length; ++i) { // load the splash textures mSplashTextures[i] = Application.Instance.Content.Load<Texture2D>(msSplashTextureNames[i]); } // set the content manager back to the global one Application.Instance.SetContentManager("Global"); When the initial load is done and the title screen starts, I do: Application.Instance.GetContentManager("UI").Unload(); The three textures take about 6.5 MB of memory. Before unloading the UI ContentManager, I see that ApplicationCurrentMemoryUsage is at 34.29 MB. After unloading the ContentManager (and doing a full GC.Collect()), it's still at 34.29 MB. But after that, I load another fullscreen texture (for the title screen background) and memory usage still doesn't change. Could it be keeping the memory for these textures allocated and reusing it? edit: very simple test: protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); PrintMemUsage("Before texture load: "); // TODO: use this.Content to load your game content here red = this.Content.Load<Texture2D>("Untitled"); PrintMemUsage("After texture load: "); } private void PrintMemUsage(string tag) { Debug.WriteLine(tag + Microsoft.Phone.Info.DeviceExtendedProperties.GetValue("ApplicationCurrentMemoryUsage")); } protected override void Update(GameTime gameTime) { // Allows the game to exit if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) this.Exit(); // TODO: Add your update logic here if (count++ == 100) { GC.Collect(); GC.WaitForPendingFinalizers(); PrintMemUsage("Before CM unload: "); this.Content.Dispose(); GC.Collect(); GC.WaitForPendingFinalizers(); PrintMemUsage("After CM unload: "); red = null; spriteBatch.Dispose(); GC.Collect(); GC.WaitForPendingFinalizers(); PrintMemUsage("After SpriteBatch Dispose(): "); } base.Update(gameTime); } protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); // TODO: Add your drawing code here if (red != null) { spriteBatch.Begin(); spriteBatch.Draw(red, new Vector2(0,0), Color.White); spriteBatch.End(); } base.Draw(gameTime); } This prints something like (it changes every time): Before texture load: 7532544 After texture load: 10727424 Before CM unload: 9875456 After CM unload: 9953280 After SpriteBatch Dispose(): 9953280

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• Career-Defining Moments

  - by Robz / Fervent Coder

  Originally posted on: http://geekswithblogs.net/robz/archive/2013/06/25/career-defining-moments.aspx Fear holds us back from many things. A little fear is healthy, but don’t let it overwhelm you into missing opportunities. In every career there is a moment when you can either step forward and define yourself, or sit down and regret it later. Why do we hold back: is it fear, constraints, family concerns, or that we simply can't do it? I think in many cases it comes to the unknown, and we are good at fearing the unknown. Some people hold back because they are fearful of what they don’t know. Some hold back because they are fearful of learning new things. Some hold back simply because to take on a new challenge it means they have to give something else up. The phrase sometimes used is “It’s the devil you know versus the one you don’t.” That fear sometimes allows us to miss great opportunities. In many people’s case it is the opportunity to go into business for yourself, to start something that never existed. Most hold back hear for a fear of failing. We’ve all heard the phrase “What would you do if you knew you couldn’t fail?”, which is intended to get people to think about the opportunities they might create. A better term I heard recently on the Ruby Rogues podcast was “What would be worth doing even if you knew you were going to fail?” I think that wording suits the intent better. If you knew (or thought) going in that you were going to fail and you didn’t care, it would open you up to the possibility of paying more attention to the journey and not the outcome. In my case it is a fear of acceptance. I am fearful that I may not learn what I need to learn or may not do a good enough job to be accepted. At the same time that fear drives me and makes me want to leap forward. Some folks would define this as “The Flinch”. I’m learning Ruby and Puppet right now. I have limited experience with both, limited to the degree it scares me some that I don’t know much about either. Okay, it scares me quite a bit! Some people’s defining moment might be going to work for Microsoft. All of you who know me know that I am in love with automation, from low-tech to high-tech automation. So for me, my “mecca” is a little different in that regard. Awhile back I sat down and defined where I wanted my career to go and it had to do more with DevOps, defined as applying developer practices to system administration operations (I could not find this definition when I searched). It’s an area that interests me and why I really want to expand chocolatey into something more awesome. I want to see Windows be as automatable and awesome as other operating systems that are out there. Back to the career-defining moment. Sometimes these moments only come once in a lifetime. The key is to recognize when you are in one of these moments and step back to evaluate it before choosing to dive in head first. So I am about to embark on what I define as one of these “moments.”  On July 1st I will be joining Puppet Labs and working to help make the Windows automation experience rock solid! I’m both scared and excited about the opportunity!

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• how to code multiple button navigation with java activities [migrated]

  - by user1738212

  Question 1: I have 2 activities. I was wondering how to optimize it. I can either create 2 activities with multiple listeners. Or create multiple java files for each button(onclick listener) Question 2: I have tried to create multiple listeners in one java but can only get one button to work. What is the syntax for multiple listeners in one java file? Here is my *updated code: now the issue is no matter what button is clicked on it leads to the same page. package install.fineline; import android.app.Activity; import android.content.Context; import android.content.Intent; import android.os.Bundle; import android.widget.Button; import android.view.View; import android.view.View.OnClickListener; public class Activity1 extends Activity2 { Button Button1; Button Button2; Button Button3; Button Button4; Button Button5; Button Button6; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fineline); addListenerOnButton(); } public void addListenerOnButton() { final Context context = this; Button1 = (Button) findViewById(R.id.autobody); Button1.setOnClickListener(new OnClickListener() { public void onClick(View arg0) { Intent intent = new Intent(context, Activity1.class); startActivity(intent); } }); Button2 = (Button) findViewById(R.id.glass); Button2.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { Intent intent = new Intent(context, Activity1.class); startActivity(intent); } }); Button3 = (Button) findViewById(R.id.wheels); Button3.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { Intent intent = new Intent(context, Activity1.class); startActivity(intent); } }); Button4 = (Button) findViewById(R.id.speedy); Button4.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { Intent intent = new Intent(context, Activity1.class); startActivity(intent); } }); Button5 = (Button) findViewById(R.id.sevan); Button5.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { Intent intent = new Intent(context, Activity1.class); startActivity(intent); } }); Button6 = (Button) findViewById(R.id.towing); Button6.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { Intent intent = new Intent(context, Activity1.class); startActivity(intent); } }); }} activity2.java package install.fineline; import android.app.Activity; import android.os.Bundle; import android.widget.Button; public class Activity2 extends Activity { Button Button1; public void onCreate1(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.autobody); } Button Button2; public void onCreate2(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.glass); } Button Button3; public void onCreate3(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.wheels); } Button button4; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.speedy); } Button Button5; public void onCreate5(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.sevan); } Button Button6; public void onCreate6(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.towing); }}

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• Application using JOGL stays in Limbo when closing

  - by Roy T.

  I'm writing a game using Java and OpenGL using the JOGL bindings. I noticed that my game doesn't terminate properly when closing the window even though I've set the closing operation of the JFrame to EXIT_ON_CLOSE. I couldn't track down where the problem was so I've made a small reproduction case. Note that on some computers the program terminates normally when closing the window but on other computers (notably my own) something in the JVM keeps lingering, this causes the JFrame to never be disposed and the application to never exit. I haven't found something in common between the computers that had difficulty terminating. All computers had Windows 7, Java 7 and the same version of JOGL and some terminated normally while others had this problem. The test case is as follows: public class App extends JFrame implements GLEventListener { private GLCanvas canvas; @Override public void display(GLAutoDrawable drawable) { GL3 gl = drawable.getGL().getGL3(); gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f); gl.glClear(GL3.GL_COLOR_BUFFER_BIT); gl.glFlush(); } // The overrides for dispose (the OpenGL one), init and reshape are empty public App(String title, boolean full_screen, int width, int height) { //snipped setting the width and height of the JFRAME GLProfile profile = GLProfile.get(GLProfile.GL3); GLCapabilities capabilities = new GLCapabilities(profile); canvas = new GLCanvas(capabilities); canvas.addGLEventListener(this); canvas.setSize(getWidth(), getHeight()); add(canvas); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //!!! setVisible(true); } @Override public void dispose() { System.out.println("HELP"); // } public static void main( String[] args ) { new App("gltut 01", false, 1280, 720); } } As you can see this doesn't do much more than adding a GLCanvas to the frame and registering the main class as the GLEventListener. So what keeps lingering? I'm not sure. I've made some screenshots. The application running normally. The application after the JFrame is closed, note that the JVM still hasn't exited or printed a return code. The application after it was force closed. Note the return code -1, so it wasnt just the JVM standing by or something the application really hadn't exited yet. So what is keeping the application in Limbo? Might it be the circular reference between the GLCanvas and the JFrame? I thought the GC could figure that out. If so how should I deal with that when I want to exit? Is there any other clean-up required when using JOGL? I've tried searching but it doesn't seem to be necessary. Edit, to clarify: there are 2 dispose functions dispose(GLAutoDrawable arg) which is a member of GLEventListener and dispose() which is a member of JFrame. The first one is called correctly (but I wouldn't know what to there, destroying the GLAutoDrawable or the GLCanvas gives an infinite exception loop) the second one is never called.

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• Don’t string together XML

  - by KyleBurns

  XML has been a pervasive tool in software development for over a decade.  It provides a way to communicate data in a manner that is simple to understand and free of platform dependencies.  Also pervasive in software development is what I consider to be the anti-pattern of using string manipulation to create XML.  This usually starts with a “quick and dirty” approach because you need an XML document and looks like (for all of the examples here, we’ll assume we’re writing the body of a method intended to take a Contact object and return an XML string): return string.Format("<Contact><BusinessName>{0}</BusinessName></Contact>", contact.BusinessName);   In the code example, I created (or at least believe I created) an XML document representing a simple contact object in one line of code with very little overhead.  Work’s done, right?  No it’s not.  You see, what I didn’t realize was that this code would be used in the real world instead of my fantasy world where I own all the data and can prevent any of it containing problematic values.  If I use this code to create a contact record for the business “Sanford & Son”, any XML parser will be incapable of processing the data because the ampersand is special in XML and should have been encoded as &amp;. Following the pattern that I have seen many times over, my next step as a developer is going to be to do what any developer in his right mind would do – instruct the user that ampersands are “bad” and they cannot be used without breaking computers.  This may work in many cases and is often accompanied by logic at the UI layer of applications to block these “bad” characters, but sooner or later someone is going to figure out that other applications allow for them and will want the same.  This often leads to the creation of “cleaner” functions that perform a replace on the strings for every special character that the person writing the function can think of.  The cleaner function will usually grow over time as support requests reveal characters that were missed in the initial cut.  Sooner or later you end up writing your own somewhat functional XML engine. I have never been told by anyone paying me to write code that they would like to buy a somewhat functional XML engine.  My employer/customer’s needs have always been for something that may use XML, but ultimately is functionality that drives business value. I’m not going to build an XML engine. So how can I generate XML that is always well-formed without writing my own engine?  Easy – use one of the ones provided to you for free!  If you’re in a shop that still supports VB6 applications, you can use the DomDocument or MXXMLWriter object (of the two I prefer MXXMLWriter, but I’m not going to fully describe either here).  For .Net Framework applications prior to the 3.5 framework, the code is a little more verbose than I would like, but easy once you understand what pieces are required:             using (StringWriter sw = new StringWriter())             {                 using (XmlTextWriter writer = new XmlTextWriter(sw))                 {                     writer.WriteStartDocument();                     writer.WriteStartElement("Contact");                     writer.WriteElementString("BusinessName", contact.BusinessName);                     writer.WriteEndElement(); // end Contact element                     writer.WriteEndDocument();                     writer.Flush();                     return sw.ToString();                 }             }   Looking at that code, it’s easy to understand why people are drawn to the initial one-liner.  Lucky for us, the 3.5 .Net Framework added the System.Xml.Linq.XElement object.  This object takes away a lot of the complexity present in the XmlTextWriter approach and allows us to generate the document as follows: return new XElement("Contact", new XElement("BusinessName", contact.BusinessName)).ToString();   While it is very common for people to use string manipulation to create XML, I’ve discussed here reasons not to use this method and introduced powerful APIs that are built into the .Net Framework as an alternative.  I’ve given a very simplistic example here to highlight the most basic XML generation task.  For more information on the XmlTextWriter and XElement APIs, check out the MSDN library.

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• The long road to bug-free software

  - by Tony Davis

  The past decade has seen a burgeoning interest in functional programming languages such as Haskell or, in the Microsoft world, F#. Though still on the periphery of mainstream programming, functional programming concepts are gradually seeping into the imperative C# language (for example, Lambda expressions have their root in functional programming). One of the more interesting concepts from functional programming languages is the use of formal methods, the lofty ideal behind which is bug-free software. The idea is that we write a specification that describes exactly how our function (say) should behave. We then prove that our function conforms to it, and in doing so have proved beyond any doubt that it is free from bugs. All programmers already use one form of specification, specifically their programming language's type system. If a value has a specific type then, in a type-safe language, the compiler guarantees that value cannot be an instance of a different type. Many extensions to existing type systems, such as generics in Java and .NET, extend the range of programs that can be type-checked. Unfortunately, type systems can only prevent some bugs. To take a classic problem of retrieving an index value from an array, since the type system doesn't specify the length of the array, the compiler has no way of knowing that a request for the "value of index 4" from an array of only two elements is "unsafe". We restore safety via exception handling, but the ideal type system will prevent us from doing anything that is unsafe in the first place and this is where we start to borrow ideas from a language such as Haskell, with its concept of "dependent types". If the type of an array includes its length, we can ensure that any index accesses into the array are valid. The problem is that we now need to carry around the length of arrays and the values of indices throughout our code so that it can be type-checked. In general, writing the specification to prove a positive property, even for a problem very amenable to specification, such as a simple sorting algorithm, turns out to be very hard and the specification will be different for every program. Extend this to writing a specification for, say, Microsoft Word and we can see that the specification would end up being no simpler, and therefore no less buggy, than the implementation. Fortunately, it is easier to write a specification that proves that a program doesn't have certain, specific and undesirable properties, such as infinite loops or accesses to the wrong bit of memory. If we can write the specifications to prove that a program is immune to such problems, we could reuse them in many places. The problem is the lack of specification "provers" that can do this without a lot of manual intervention (i.e. hints from the programmer). All this might feel a very long way off, but computing power and our understanding of the theory of "provers" advances quickly, and Microsoft is doing some of it already. Via their Terminator research project they have started to prove that their device drivers will always terminate, and in so doing have suddenly eliminated a vast range of possible bugs. This is a huge step forward from saying, "we've tested it lots and it seems fine". What do you think? What might be good targets for specification and verification? SQL could be one: the cost of a bug in SQL Server is quite high given how many important systems rely on it, so there's a good incentive to eliminate bugs, even at high initial cost. [Many thanks to Mike Williamson for guidance and useful conversations during the writing of this piece] Cheers, Tony.

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• Appropriate design / technologies to handle dynamic string formatting?

  - by Mark W

  recently I was tasked with implementing a way of adding support for versioning of hardware packet specifications to one of our libraries. First a bit of information about the project. We have a hardware library which has classes for each of the various commands we support sending to our hardware. These hardware modules are essentially just lights with a few buttons, and a 2 or 4 digit display. The packets typically follow the format {SOH}AADD{ETX}, where AA is our sentinel action code, and DD is the device ID. These packet specs are different from one command to the next obviously, and the different firmware versions we have support different specifications. For example, on version 1 an action code of 14 may have a spec of {SOH}AADDTEXT{ETX} which would be AA = 14 literal, DD = device ID, TEXT = literal text to display on the device. Then we come out with a revision with adds an extended byte(s) onto the end of the packet like this {SOH}AADDTEXTE{ETX}. Assume the TEXT field is fixed width for this example. We have now added a new field onto the end which could be used to say specify the color or flash rate of the text/buttons. Currently this java library only supports one version of the commands, the latest. In our hardware library we would have a class for this command, say a DisplayTextArgs.java. That class would have fields for the device ID, the text, and the extended byte. The command class would expose a method which generates the string ("{SOH}AADDTEXTE{ETX}") using the value from the class. In practice we would create the Args class as needed, populate the fields, call the method to get our packet string, then ship that down across the CAN. Some of our other commands specification can vary for the same command, on the same version, depending on some runtime state. For example, another command for version 1 may be {SOH}AA{ETX}, where this action code clears all of the modules behind a specific controller device of their text. We may overload this packet to have option fields with multiple meanings like {SOH}AAOC{ETX} where OC is literal text, which tells the controller to only clear text on a specific module type, and to leave the others alone, or the spec could also have an option format of {SOH}AADD{ETX} to clear the text off a a specific device. Currently, in the method which generates the packet string, we would evaluate fields on the args class to determine which spec we will be using when formatting the packet. For this example, it would be along the lines of: if m_DeviceID != null then use {SOH}AADD{ETX} else if m_ClearOCs == true then use {SOH}AAOC{EXT} else use {SOH}AA{ETX} I had considered using XML, or a database to store String.format format strings, which were linked to firmware version numbers in some table. We would load them up at startup, and pass in the version number of the hardwares firmware we are currently using (I can query the devices for their firmware version, but the version is not included in all packets as part of the spec). This breaks down pretty quickly because of the dynamic nature of how we select which version of the command to use. I then considered using a rule engine to possibly build out expressions which could be interpreted at runtume, to evaluate the args class's state, and from that select the appropriate format string to use, but my brief look at rule engines for java scared me away with its complexity. While it seems like it might be a viable solution, it seems overly complex. So this is why I am here. I wouldn't say design is my strongest skill, and im having trouble figuring out the best way to approach this problem. I probably wont be able to radically change the args classes, but if the trade off was good enough, I may be able to convince my boss that the change is appropriate. What I would like from the community is some feedback on some best practices / design methodologies / API or other resources which I could use to accomplish: Logic to determine which set of commands to use for a given firmware version Of those command, which version of each command to use (based on the args classes state) Keep the rules logic decoupled from the application so as to avoid needing releases for every firmware version Be simple enough so I don't need weeks of study and trial and error to implement effectively.

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• Rethinking Oracle Optimizer Statistics for P6 Part 2

  - by Brian Diehl

  In the previous post (Part 1), I tried to draw some key insights about the relationship between P6 and Oracle Optimizer Statistics.  The first is that average cardinality has the greatest impact on query optimization and that the particular queries generated by P6 are more likely to use this average during calculations. The second is that these are statistics that are unlikely to change greatly over the life of the application. Ultimately, our goal is to get the best query optimization possible.  Or is it? Stability No application administrator wants to get the call at 9am that their application users cannot get there work done because everything is running slow. This is a possibility with a regularly scheduled nightly collection of statistics. It may not just be slow performance, but a complete loss of service because one or more queries are optimized poorly. Ideally, this should not be the case. The database optimizer should make better decisions with more up-to-date data. Better statistics may give incremental performance benefit. However, this benefit must be balanced against the potential cost of system down time.  It is stability that we ultimately desire and not absolute optimal performance. We do want the benefit from more accurate statistics and better query plans, but not at the risk of an unusable system. As a result, I've developed the following methodology around managing database statistics for the P6 database.  1. No Automatic Re-Gathering - The daily, weekly, or other interval of statistic gathering is unlikely to be beneficial. Quite the opposite. It is more likely to cause problems. 2. Smart Re-Gathering - The time to collect statistics is when things have changed significantly. For a new installation of P6, this is happening more often because the data is growing from a few rows to thousands and more. But for a mature system, the data is not changing significantly from week-to-week. There are times to collect statistics: New releases of the application Changes in the underlying hardware or software versions (ex. new Oracle RDBMS version) When additional user groups are added. The new groups may use the software in significantly different ways. After significant changes in the data. This may be monthly, quarterly or yearly.  3. Always Test - If you take away one thing from this post, it would be to always have a plan to test after changing statistics. In reality, statistics can be collected as often as you desire provided there are tests in place to verify that performance is the same or better. These might be automated tests or simply a manual script of application functions. 4. Have a Way Out - Never change the statistics without a way to return to the previous set. Think of the statistics as one part of the overall application code that also includes the source code--both application and RDBMS. It would be foolish to change to the new code without a way to get back to the previous version. In the final post, I will talk about the actual script I created for P6 PMDB and possible future direction for managing query performance. 

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• Is my class structure good enough?

  - by Rivten

  So I wanted to try out this challenge on reddit which is mostly about how you structure your data the best you can. I decided to challenge my C++ skills. Here's how I planned this. First, there's the Game class. It deals with time and is the only class main has access to. A game has a Forest. For now, this class does not have a lot of things, only a size and a Factory. Will be put in better use when it will come to SDL-stuff I guess A Factory is the thing that deals with the Game Objects (a.k.a. Trees, Lumberjack and Bears). It has a vector of all GameObjects and a queue of Events which will be managed at the end of one month. A GameObject is an abstract class which can be updated and which can notify the Event Listener The EventListener is a class which handles all the Events of a simulation. It can recieve events from a Game Object and notify the Factory if needed, the latter will manage correctly the event. So, the Tree, Lumberjack and Bear classes all inherits from GameObject. And Sapling and Elder Tree inherits from Tree. Finally, an Event is defined by an event_type enumeration (LUMBERJACK_MAWED, SAPPLING_EVOLUTION, ...) and an event_protagonists union (a GameObject or a pair of GameObject (who killed who ?)). I was quite happy at first with this because it seems quite logic and flexible. But I ended up questionning this structure. Here's why : I dislike the fact that a GameObject need to know about the Factory. Indeed, when a Bear moves somewhere, it needs to know if there's a Lumberjack ! Or it is the Factory which handles places and objects. It would be great if a GameObject could only interact with the EventListener... or maybe it's not that much of a big deal. Wouldn't it be better if I separate the Factory in three vectors ? One for each kind of GameObject. The idea would be to optimize research. If I'm looking do delete a dead lumberjack, I would only have to look in one shorter vector rather than a very long vector. Another problem arises when I want to know if there is any particular object in a given case because I have to look for all the gameObjects and see if they are at the given case. I would tend to think that the other idea would be to use a matrix but then the issue would be that I would have empty cases (and therefore unused space). I don't really know if Sapling and Elder Tree should inherit from Tree. Indeed, a Sapling is a Tree but what about its evolution ? Should I just delete the sapling and say to the factory to create a new Tree at the exact same place ? It doesn't seem natural to me to do so. How could I improve this ? Is the design of an Event quite good ? I've never used unions before in C++ but I didn't have any other ideas about what to use. Well, I hope I have been clear enough. Thank you for taking the time to help me !

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• Taking a look at the Mindscape Phone Elements for WP7.

  - by mbcrump

  I recently heard that Mindscape HQ had released the Windows Phone 7 Controls and had to take a look at them. 100 FREE LICENSE GIVEAWAY! Before we get to the screenshots, you will be pleased to learn that my usergroup called “Allaboutxaml” has partnered with Mindscape HQ and are giving away 100 license. You can check out the site here to get your free controls. But please hurry as after the 100 are gone then I will not have any more to give away! A few links to read first: The official blog post from Mindscape HQ detailing the release. They also have the links to download the trial and get started. The phone elements official forum! So, let’s get started. After you download the controls go ahead and double click the .exe to get started installing them. After everything is installed then you will have the following program group. I’d recommend clicking on the Phone Elements Directory to get started: Let’s go over each element: Bin – Just the .DLL that’s required to use Mindscape HQ WP7 Controls in your project. Documentation – a .CHM File that will show you how to get your project up and running quickly. Resources – Just a few image files Samples – This is a full WP7 project that details every controls. The thing that I was most interested in was how the controls look and is it easy to use. I always believed if your paying for controls then you should hold my hand through using them. You will be pleased to know that Mindscape made it very easy to use. First, the WP7 project in the “Samples” folder just works. Double click on the solution file and you are in an emulator looking at the controls. Since you have the source code for every control, it’s a matter of copying/pasting the code in your project to get it to work. What I did, was play with the controls in the emulator until I found one I could use. Then I looked at the Visual Studio solution and found the Page that contained the control. Mindscape makes this very easy to do with their layout: So, the one that I was interested in was the Looping List Box.  Here is a demo of it: I wanted to see how they were populating the numbers 1-100 so I found the code behind and noticed it was just this one line. LoopingListBox1.DataSource = new NumericDataSource() { MinValue = 1, MaxValue = 100 }; In case you are wondering, the NumericDataSource was created by MindScape and you can view the Declaration to find out more about it:   So, the controls are pretty much that easy to use. Play with the emulator and find the control you want to use. Find the XAML file in the Sample Solution and copy/paste the code. Let’s go ahead and take a look at the controls available: They also have a great variety of Charting controls: Overall it’s a nice set of WP7 controls. Feel free to leave a comment below on anything you would like to see and I will make sure that Mindscape HQ get the message. Don’t forget if you are the first 100 people reading this article then you will get a free license.  Subscribe to my feed CodeProject

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• Reading graph inputs for a programming puzzle and then solving it

  - by Vrashabh

  I just took a programming competition question and I absolutely bombed it. I had trouble right at the beginning itself from reading the input set. The question was basically a variant of this puzzle http://codercharts.com/puzzle/evacuation-plan but also had an hour component in the first line(say 3 hours after start of evacuation). It reads like this This puzzle is a tribute to all the people who suffered from the earthquake in Japan. The goal of this puzzle is, given a network of road and locations, to determine the maximum number of people that can be evacuated. The people must be evacuated from evacuation points to rescue points. The list of road and the number of people they can carry per hour is provided. Input Specifications Your program must accept one and only one command line argument: the input file. The input file is formatted as follows: the first line contains 4 integers n r s t n is the number of locations (each location is given by a number from 0 to n-1) r is the number of roads s is the number of locations to be evacuated from (evacuation points) t is the number of locations where people must be evacuated to (rescue points) the second line contains s integers giving the locations of the evacuation points the third line contains t integers giving the locations of the rescue points the r following lines contain to the road definitions. Each road is defined by 3 integers l1 l2 width where l1 and l2 are the locations connected by the road (roads are one-way) and width is the number of people per hour that can fit on the road Now look at the sample input set 5 5 1 2 3 0 3 4 0 1 10 0 2 5 1 2 4 1 3 5 2 4 10 The 3 in the first line is the additional component and is defined as the number of hours since the resuce has started which is 3 in this case. Now my solution was to use Dijisktras algorithm to find the shortest path between each of the rescue and evac nodes. Now my problem started with how to read the input set. I read the first line in python and stored the values in variables. But then I did not know how to store the values of the distance between the nodes and what DS to use and how to input it to say a standard implementation of dijikstras algorithm. So my question is two fold 1.) How do I take the input of such problems? - I have faced this problem in quite a few competitions recently and I hope I can get a simple code snippet or an explanation in java or python to read the data input set in such a way that I can input it as a graph to graph algorithms like dijikstra and floyd/warshall. Also a solution to the above problem would also help. 2.) How to solve this puzzle? My algorithm was: Find shortest path between evac points (in the above example it is 14 from 0 to 3) Multiply it by number of hours to get maximal number of saves Also the answer given for the variant for the input set was 24 which I dont understand. Can someone explain that also. UPDATE: I get how the answer is 14 in the given problem link - it seems to be just the shortest path between node 0 and 3. But with the 3 hour component how is the answer 24 UPDATE I get how it is 24 - its a complete graph traversal at every hour and this is how I solve it Hour 1 Node 0 to Node 1 - 10 people Node 0 to Node 2- 5 people TotalRescueCount=0 Node 1=10 Node 2= 5 Hour 2 Node 1 to Node 3 = 5(Rescued) Node 2 to Node 4 = 5(Rescued) Node 0 to Node 1 = 10 Node 0 to Node 2 = 5 Node 1 to Node 2 = 4 TotalRescueCount = 10 Node 1 = 10 Node 2= 5+4 = 9 Hour 3 Node 1 to Node 3 = 5(Rescued) Node 2 to Node 4 = 5+4 = 9(Rescued) TotalRescueCount = 9+5+10 = 24 It hard enough for this case , for multiple evac and rescue points how in the world would I write a pgm for this ?

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• My Favorite Free Windows Phone Twitter App

  - by Tim Murphy

  Windows Phone 7 has been out for about two years now.  In that time I have switched back and forth with different free Twitter apps.  Mostly the has been because someone has mentioned one or another that they like.  I figured I would give a quick run down of what I felt were the pros and cons of each.  These are only the ones that I have used and your mileage may vary.  So here we go. WP7 Built-In Twitter Functionality While it is great that Microsoft put this functionality in, it is extremely limited in usefulness.  Some apps leverage it to allow you to share pictures or information they contain.  In all though, I don’t use it unless it is the quickest way to get something out. Official Twitter App The official Twitter app isn’t a very big step up from the phone functionality.  It gives you a better timeline view and better attachment handling, but it makes you bounce to a browser page to see images that are linked to a tweet. TweetCaster This was my main Twitter app for quite a while.  It is the only one with InstaPaper integration so that you can save you a tweet and review it later.  My main problem is that it crashes too much when it can’t find a connection.  It also only previews yfrog and twitpic images and only once you go to the detail of a tweet.  Other than that it is a solid Twitter client. moTweets This is my current favorite. It has nice image display in your timeline which I have not seen on any of the other apps.  There are two modes that you can use with this app.  The first is standard to most Twitter apps that allows you to navigate to a tweet and do the usual operations.  The second is what they call Quick Buttons.  In this case you do not see the content of the tweet but go straight to the let’s get something done stage.  It is an interesting take.  I do miss the Instapaper integration and it has a tendency to show a blank timeline list once in a while after you view detail entry.  If you scroll the list it restore your timeline, but you lose you place and are put to the first entry. Seesmic I am not very fond of this app.  The first thing is that it makes you pick a “Space” when you enter the app.  This is really “which account do you want to see”.  On top of that it does not show who retweeted an entry in your timeline and then only tells you how many people RT the post when you look at the detail.  There is a Speak feature that will read you a single tweet, but you have to navigate to the tweet and then to a menu to make it work.  We will have to see if this gets better with the features in Windows Phone 8.  Other than that it is another basic feature app.  Summary In the end I am sticking with moTweets.  I would appreciate it if they added the Instapaper capability and fixed the one bug.  If they did that I would be really happy with the product. del.icio.us Tags: Twitter,Windows Phone 7,WP7,TweetCaster,moTweets,Seesmic

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• I thought the new AUTO_SAMPLE_SIZE in Oracle Database 11g looked at all the rows in a table so why do I see a very small sample size on some tables?

  - by Maria Colgan

  I recently got asked this question and thought it was worth a quick blog post to explain in a little more detail what is going on with the new AUTO_SAMPLE_SIZE in Oracle Database 11g and what you should expect to see in the dictionary views. Let’s take the SH.CUSTOMERS table as an example.  There are 55,500 rows in the SH.CUSTOMERS tables. If we gather statistics on the SH.CUSTOMERS using the new AUTO_SAMPLE_SIZE but without collecting histogram we can check what sample size was used by looking in the USER_TABLES and USER_TAB_COL_STATISTICS dictionary views. The sample sized shown in the USER_TABLES is 55,500 rows or the entire table as expected. In USER_TAB_COL_STATISTICS most columns show 55,500 rows as the sample size except for four columns (CUST_SRC_ID, CUST_EFF_TO, CUST_MARTIAL_STATUS, CUST_INCOME_LEVEL ). The CUST_SRC_ID and CUST_EFF_TO columns have no sample size listed because there are only NULL values in these columns and the statistics gathering procedure skips NULL values. The CUST_MARTIAL_STATUS (38,072) and the CUST_INCOME_LEVEL (55,459) columns show less than 55,500 rows as their sample size because of the presence of NULL values in these columns. In the SH.CUSTOMERS table 17,428 rows have a NULL as the value for CUST_MARTIAL_STATUS column (17428+38072 = 55500), while 41 rows have a NULL values for the CUST_INCOME_LEVEL column (41+55459 = 55500). So we can confirm that the new AUTO_SAMPLE_SIZE algorithm will use all non-NULL values when gathering basic table and column level statistics. Now we have clear understanding of what sample size to expect lets include histogram creation as part of the statistics gathering. Again we can look in the USER_TABLES and USER_TAB_COL_STATISTICS dictionary views to find the sample size used. The sample size seen in USER_TABLES is 55,500 rows but if we look at the column statistics we see that it is same as in previous case except  for columns  CUST_POSTAL_CODE and  CUST_CITY_ID. You will also notice that these columns now have histograms created on them. The sample size shown for these columns is not the sample size used to gather the basic column statistics. AUTO_SAMPLE_SIZE still uses all the rows in the table - the NULL rows to gather the basic column statistics (55,500 rows in this case). The size shown is the sample size used to create the histogram on the column. When we create a histogram we try to build it on a sample that has approximately 5,500 non-null values for the column.  Typically all of the histograms required for a table are built from the same sample. In our example the histograms created on CUST_POSTAL_CODE and the CUST_CITY_ID were built on a single sample of ~5,500 (5,450 rows) as these columns contained only non-null values. However, if one or more of the columns that requires a histogram has null values then the sample size maybe increased in order to achieve a sample of 5,500 non-null values for those columns. n addition, if the difference between the number of nulls in the columns varies greatly, we may create multiple samples, one for the columns that have a low number of null values and one for the columns with a high number of null values.  This scheme enables us to get close to 5,500 non-null values for each column. +Maria Colgan

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