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• Clean Code Development & Flexible work environment - MSCC 26.10.2013

  Finally, some spare time to summarize my impressions and experiences of the recent meetup of Mauritius Software Craftsmanship Community. I already posted my comment on the event and on our social media networks: Professional - It's getting better with our meetups and I really appreciated that 'seniors' and 'juniors' were present today. Despite running a little bit out of time it was really great to see more students coming to the gathering. This time we changed location for our Saturday meetup and it worked out very well. A big thank you to Ebene Accelerator, namely Mrs Poonum, for the ability to use their meeting rooms for our community get-together. Already some weeks ago I had a very pleasant conversation with her about the MSCC aims, 'mission' and how we organise things. Additionally, I think that an environment like the Ebene Accelerator is a good choice as it acts as an incubator for young developers and start-ups. Reactions from other craftsmen Before I put my thoughts about our recent meeting down, I'd like to mention and cross-link to some of the other craftsmen that were present: "MSCC meet up is a massive knowledge gaining strategies for students, future entrepreneurs, or for geeks all around. Knowledge sharing becomes a fun. For those who have not been able to made it do subscribe on our MSCC meet up group at meetup.com." -- Nitin on Learning is fun with #MSCC #Ebene Accelerator "We then talked about the IT industry in Mauritius, salary issues in various field like system administration, software development etc. We analysed the reasons why people tend to hop from one company to another. That was a fun debate." -- Ish on MSCC meetup - Gang of Geeks "Flexible Learning Environment was quite interesting since these lines struck cords : "You're not a secretary....9 to 5 shouldn't suit you"....This allowed reflection...deep reflection....especially regarding the local mindset...which should be changed in a way which would promote creativity rather than choking it till death..." -- Yannick on 2nd MSCC Monthly Meet-up And others on Facebook... ;-) Visual impressions are available on our Meetup event page. More first time attendees We great pleasure I noticed that we have once again more first time visitors. A quick overlook showed that we had a majority of UoM students in first, second or last year. Some of them are already participating in the UoM Computer Club or are nominated as members of the Microsoft Student Partner (MSP) programme. Personally, I really appreciate the fact that the MSCC is able to gather such a broad audience. And as I wrote initially, the MSCC is technology-agnostic; we want IT people from any segment of this business. Of course, students which are about to delve into the 'real world' of working are highly welcome, and I hope that they might get one or other glimpse of experience or advice from employees. Sticking to the schedule? No, not really... And honestly, it was a good choice to go a little bit of the beaten tracks. I mean, yes we have a 'rough' agenda of topics that we would like to talk about or having a presentation about. But we keep it 'agile'. Due to the high number of new faces, we initiated another quick round of introductions and I gave a really brief overview of the MSCC. Next, we started to reflect on the Clean Code Developer (CCD) - Red Grade which we introduced on the last meetup. Nirvan was the lucky one and he did a good job on summarizing the various abbreviations of the first level of being a CCD. Actually, more interesting, we exchanged experience about the principles and practices of Red Grade, and it was very informative to get to know that Yann actually 'interviewed' a couple of friends, other students, local guys working in IT companies as well as some IT friends from India in order to counter-check on what he learned first-hand about Clean Code. Currently, he is reading the book of Robert C. Martin on that topic and I'm looking forward to his review soon. More output generates more input What seems to be like a personal mantra is working out pretty well for me since the beginning of this year. Being more active on social media networks, writing more article on my blog, starting the Mauritius Software Craftsmanship Community, and contributing more to other online communities has helped me to receive more project requests, job offers and possibilities to expand my business at IOS Indian Ocean Software Ltd. Actually, it is not a coincidence that one of the questions new craftsmen should answer during registration asks about having a personal blog. Whether you are just curious about IT, right in the middle of your Computer Studies, or already working in software development or system administration since a while you should consider to advertise and market yourself online. Easiest way to resolve this are to have online profiles on professional social media networks like LinkedIn, Xing, Twitter, and Google+ (no Facebook should be considered for private only), and considering to have a personal blog. Why? -- Be yourself, be proud of your work, and let other people know that you're passionate about your profession. Trust me, this is going to open up opportunities you might not have dreamt about... Exchanging ideas about having a professional online presence - MSCC meetup on the 26th October 2013 Furthermore, consider to put your Curriculum Vitae online, too. There are quite a number of service providers like 1ClickCV, Stack Overflow Careers 2.0, etc. which give you the ability to have an up to date CV online. At least put it on your site, next to your personal blog. Similar to what you would be able to see on my site here. Cyber Island Mauritius - are we there? A couple of weeks ago I got a 'cold' message on LinkedIn from someone living in the U.S. asking about the circumstances and conditions of the IT world of Mauritius. He has a great business idea, venture capital and is currently looking for a team of software developers (mainly mobile - iOS) for a new startup here in Mauritius. Since then we exchanged quite some details through private messages and Skype conversations, and I suggested that it might be a good chance to join our meetup through a conference call and see for yourself about potential candidates. During approximately 30 to 40 minutes the brief idea of the new startup was presented - very promising state-of-the-art technology aspects and integration of various public APIs -, and we had a good Q&A session about it. Also thanks to the excellent bandwidth provided by the Ebene Accelerator the video conference between three parties went absolutely well. Clean Code Developer - Orange Grade Hahaha - nice one... Being at the Orange Tower at Ebene and then talking about an Orange Grade as CCD. Well, once again I provided an overview of the principles and practices in that rank of Clean Code, and similar to our last meetup we discussed on the various aspect of each principle, whether someone already got in touch with it during studies or work, and how it could affect their future view on their source code. Following are the principles and practices of Clean Code Developer - Orange Grade: CCD Orange Grade - Principles Single Level of Abstraction (SLA) Single Responsibility Principle (SRP) Separation of Concerns (SoC) Source Code conventions CCD Orange Grade - Practices Issue Tracking Automated Integration Tests Reading, Reading, Reading Reviews Especially the part on reading technical books got some extra attention. We quickly gathered our views on that and came up with a result that ranges between Zero (0) and up to Fifteen (15) book titles per year. Personally, I'm keeping my progress between Six (6) and Eight (8) titles per year, but at least One (1) per quarter of a year. Which is also connected to the fact that I'm participating in the O'Reilly Reader Review Program and have a another benefit to get access to free books only by writing and publishing a review afterwards. We also had a good exchange on the extended topic of 'Reviews' - which to my opinion is abnormal difficult here in Mauritius for various reasons. As far as I can tell from my experience working with Mauritian software developers, either as colleagues, employees or during consulting services there are unfortunately two dominant pattern on that topic: Keeping quiet Running away Honestly, I have no evidence about why these are the two 'solutions' on reviews but that's the situation that I had to face over the last couple of years. Sitting together and talking about problematic issues, tackling down root causes of de-motivational activities and working on general improvements doesn't seem to have a ground within the IT world of Mauritius. Are you a typist or a creative software craftsman? - MSCC meetup on the 26th October 2013 One very good example that we talked about was the fact of 'job hoppers' as you can easily observe it on someone's CV - those people change job every single year; for no obvious reason! Frankly speaking, I wouldn't even consider an IT person like to for an interview. As a company you're investing money and effort into the abilities of your employees. Hiring someone that won't stay for a longer period is out of question. And sorry to say, these kind of IT guys smell fishy about their capabilities and more likely to cause problems than actually produce productive results. One of the reasons why there is a probation period on an employment contract is to give you the liberty to leave as early as possible in case that you don't like your new position. Don't fool yourself or waste other people's time and money by hanging around a full year only to snatch off the bonus payment... Future outlook: Developer's Conference Even though it is not official yet I already mentioned it several times during our weekly Code & Coffee sessions. The MSCC is looking forward to be able to organise or to contribute to an upcoming IT event. Currently, the rough schedule is set for April 2014 but this mainly depends on availability of location(s), a decent time frame for preparations, and the underlying procedures with public bodies to have it approved and so on. As soon as the information about date and location has been fixed there will be a 'Call for Papers' period in order to attract local IT enthusiasts to apply for a session slot and talk about their field of work and their passion in IT. More to come for sure... My resume of the day It was a great gathering and I am very pleased about the fact that we had another 15 craftsmen (plus 2 businessmen on conference call plus 2 young apprentices) in the same room, talking about IT related topics and sharing their experience as employees and students. Personally, I really appreciated the feedback from the students about their current view on their future career, and I really hope that some of them are going to pursue their dreams. Start promoting yourself and it will happen... Looking forward to your blogs! And last but not least our numbers on Meetup and Facebook have been increased as a direct consequence of this meetup. Please, spread the word about the MSCC and get your friends and colleagues to join our official site. The higher the number of craftsmen we have the better chances we have t achieve something great! Thanks!

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• Super constructor must be a first statement in Java constructor [closed]

  - by Val

  I know the answer: "we need rules to prevent shooting into your own foot". Ok, I make millions of programming mistakes every day. To be prevented, we need one simple rule: prohibit all JLS and do not use Java. If we explain everything by "not shooting your foot", this is reasonable. But there is not much reason is such reason. When I programmed in Delphy, I always wanted the compiler to check me if I read uninitializable. I have discovered myself that is is stupid to read uncertain variable because it leads unpredictable result and is errorenous obviously. By just looking at the code I could see if there is an error. I wished if compiler could do this job. It is also a reliable signal of programming error if function does not return any value. But I never wanted it do enforce me the super constructor first. Why? You say that constructors just initialize fields. Super fields are derived; extra fields are introduced. From the goal point of view, it does not matter in which order you initialize the variables. I have studied parallel architectures and can say that all the fields can even be assigned in parallel... What? Do you want to use the unitialized fields? Stupid people always want to take away our freedoms and break the JLS rules the God gives to us! Please, policeman, take away that person! Where do I say so? I'm just saying only about initializing/assigning, not using the fields. Java compiler already defends me from the mistake of accessing notinitialized. Some cases sneak but this example shows how this stupid rule does not save us from the read-accessing incompletely initialized in construction: public class BadSuper { String field; public String toString() { return "field = " + field; } public BadSuper(String val) { field = val; // yea, superfirst does not protect from accessing // inconstructed subclass fields. Subclass constr // must be called before super()! System.err.println(this); } } public class BadPost extends BadSuper { Object o; public BadPost(Object o) { super("str"); this. o = o; } public String toString() { // superconstructor will boom here, because o is not initialized! return super.toString() + ", obj = " + o.toString(); } public static void main(String[] args) { new BadSuper("test 1"); new BadPost(new Object()); } } It shows that actually, subfields have to be inilialized before the supreclass! Meantime, java requirement "saves" us from writing specializing the class by specializing what the super constructor argument is, public class MyKryo extends Kryo { class MyClassResolver extends DefaultClassResolver { public Registration register(Registration registration) { System.out.println(MyKryo.this.getDepth()); return super.register(registration); } } MyKryo() { // cannot instantiate MyClassResolver in super super(new MyClassResolver(), new MapReferenceResolver()); } } Try to make it compilable. It is always pain. Especially, when you cannot assign the argument later. Initialization order is not important for initialization in general. I could understand that you should not use super methods before initializing super. But, the requirement for super to be the first statement is different. It only saves you from the code that does useful things simply. I do not see how this adds safety. Actually, safety is degraded because we need to use ugly workarounds. Doing post-initialization, outside the constructors also degrades safety (otherwise, why do we need constructors?) and defeats the java final safety reenforcer. To conclude Reading not initialized is a bug. Initialization order is not important from the computer science point of view. Doing initalization or computations in different order is not a bug. Reenforcing read-access to not initialized is good but compilers fail to detect all such bugs Making super the first does not solve the problem as it "Prevents" shooting into right things but not into the foot It requires to invent workarounds, where, because of complexity of analysis, it is easier to shoot into the foot doing post-initialization outside the constructors degrades safety (otherwise, why do we need constructors?) and that degrade safety by defeating final access modifier When there was java forum alive, java bigots attecked me for these thoughts. Particularly, they dislaked that fields can be initialized in parallel, saying that natural development ensures correctness. When I replied that you could use an advanced engineering to create a human right away, without "developing" any ape first, and it still be an ape, they stopped to listen me. Cos modern technology cannot afford it. Ok, Take something simpler. How do you produce a Renault? Should you construct an Automobile first? No, you start by producing a Renault and, once completed, you'll see that this is an automobile. So, the requirement to produce fields in "natural order" is unnatural. In case of alarmclock or armchair, which are still chair and clock, you may need first develop the base (clock and chair) and then add extra. So, I can have examples where superfields must be initialized first and, oppositely, when they need to be initialized later. The order does not exist in advance. So, the compiler cannot be aware of the proper order. Only programmer/constructor knows is. Compiler should not take more responsibility and enforce the wrong order onto programmer. Saying that I cannot initialize some fields because I did not ininialized the others is like "you cannot initialize the thing because it is not initialized". This is a kind of argument we have. So, to conclude once more, the feature that "protects" me from doing things in simple and right way in order to enforce something that does not add noticeably to the bug elimination at that is a strongly negative thing and it pisses me off, altogether with the all the arguments to support it I've seen so far. It is "a conceptual question about software development" Should there be the requirement to call super() first or not. I do not know. If you do or have an idea, you have place to answer. I think that I have provided enough arguments against this feature. Lets appreciate the ones who benefit form it. Let it just be something more than simple abstract and stupid "write your own language" or "protection" kind of argument. Why do we need it in the language that I am going to develop?

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• Navigation in Win8 Metro Style applications

  - by Dennis Vroegop

  In Windows 8, Touch is, as they say, a first class citizen. Now, to be honest: they also said that in Windows 7. However in Win8 this is actually true. Applications are meant to be used by touch. Yes, you can still use mouse, keyboard and pen and your apps should take that into account but touch is where you should focus on initially. Will all users have touch enabled devices? No, not in the first place. I don’t think touchscreens will be on every device sold next year. But in 5 years? Who knows? Don’t forget: if your app is successful it will be around for a long time and by that time touchscreens will be everywhere. Another reason to embrace touch is that it’s easier to develop a touch-oriented app and then to make sure that keyboard, nouse and pen work as doing it the other way around. Porting a mouse-based application to a touch based application almost never works. The reverse gives you much more chances for success. That being said, there are some things that you need to think about. Most people have more than one finger, while most users only use one mouse at the time. Still, most touch-developers translate their mouse-knowledge to the touch and think they did a good job. Martin Tirion from Microsoft said that since Touch is a new language people face the same challenges they do when learning a new real spoken language. The first thing people try when learning a new language is simply replace the words in their native language to the newly learned words. At first they don’t care about grammar. To a native speaker of that other language this sounds all wrong but they still will be able to understand what the intention was. If you don’t believe me: try Google translate to translate something for you from your language to another and then back and see what happens. The same thing happens with Touch. Most developers translate a mouse-click into a tap-event and think they’re done. Well matey, you’re not done. Not by far. There are things you can do with a mouse that you cannot do with touch. Think hover. A mouse has the ability to ‘slide’ over UI elements. Touch doesn’t (I know: with Pen you can do this but I’m talking about actual fingers here). A touch is either there or it isn’t. And right-click? Forget about it. A click is a click.  Yes, you have more than one finger but the machine doesn’t know which finger you use… The other way around is also true. Like I said: most users only have one mouse but they are likely to have more than one finger. So how do we take that into account? Thinking about this is really worth the time: you might come up with some surprisingly good ideas! Still: don’t forget that not every user has touch-enabled hardware so make sure your app is useable for both groups. Keep this in mind: we’re going to need it later on! Now. Apps should be easy to use. You don’t want your user to read through pages and pages of documentation before they can use the app. Imagine that spotter next to an airfield suddenly seeing a prototype of a Concorde 2 landing on the nearby runway. He probably wants to enter that information in our app NOW and not after he’s taken a 3 day course. Even if he still has to download the app, install it for the first time and then run it he should be on his way immediately. At least, fast enough to note down the details of that unique, rare and possibly exciting sighting he just did. So.. How do we do this? Well, I am not talking about games here. Games are in a league of their own. They fall outside the scope of the apps I am describing. But all the others can roughly be characterized as being one of two flavors: the navigation is either flat or hierarchical. That’s it. And if it’s hierarchical it’s no more than three levels deep. Not more. Your users will get lost otherwise and we don’t want that. Flat is simple. Just imagine we have one screen that is as high as our physical screen is and as wide as you need it to be. Don’t worry if it doesn’t fit on the screen: people can scroll to the right and left. Don’t combine up/down and left/right scrolling: it’s confusing. Next to that, since most users will hold their device in landscape mode it’s very natural to scroll horizontal. So let’s use that when we have a flat model. The same applies to the hierarchical model. Try to have at most three levels. If you need more space, find a way to group the items in such a way that you can fit it in three, very wide lanes. At the highest level we have the so called hub level. This is the entry point of the app and as such it should give the user an immediate feeling of what the app is all about. If your app has categories if items then you might show these categories here. And while you’re at it: also show 2 or 3 of the items itself here to give the user a taste of what lies beneath. If the user selects a category you go to the section part. Here you show several sections (again, go as wide as you need) with again some detail examples. After that: the details layer shows each item. By giving some samples of the underlaying layer you achieve several things: you make the layer attractive by showing several different things, you show some highlights so the user sees actual content and you provide a shortcut to the layers underneath. The image below is borrowed from the http://design.windows.com website which has tons and tons of examples: For our app we’ll use this layout. So what will we show? Well, let’s see what sorts of features our app has to offer. I’ll repeat them here: Note planes Add pictures of that plane Notify friends of new spots Share new spots on social media Write down arrival times Write down departure times Write down the runway they take I am sure you can think of some more items but for now we'll use these. In the hub we’ll show something that represents “Spots”, “Friends”, “Social”. Apparently we have an inner list of spotter-friends that are in the app, while we also have to whole world in social. In the layer below we show something else, depending on what the user choose. When they choose “Spots” we’ll display the last spots, last spots by our friends (so we can actually jump from this category to the one next to it) and so on. When they choose a “spot” (or press the + icon in the App bar, which I’ll talk about next time) they go to the lowest and final level that shows details about that spot, including a picture, date and time and the notes belonging to that entry. You’d be amazed at how easy it is to organize your app this way. If you don’t have enough room in these three layers you probably could easily get away with grouping items. Take a look at our hub: we have three completely different things in one place. If you still can’t fit it all in in a logical and consistent way, chances are you are trying to do too much in this app. Go back to your mission statement, determine if it is specific enough and if your feature list helps that statement or makes it unclear. Go ahead. Give it a go! Next time we’ll talk about the look and feel, the charms and the app-bar….

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• Big data: An evening in the life of an actual buyer

  - by Jean-Pierre Dijcks

  Here I am, and this is an actual story of one of my evenings, trying to spend money with a company and ultimately failing. I just gave up and bought a service from another vendor, not the incumbent. Here is that story and how I think big data could actually fix this (and potentially prevent some of this from happening). In the end this story should illustrate how big data can benefit me (get me what I want without causing grief) and the company I am trying to buy something from. Note: Lots of details left out, I have no intention of being the annoyed blogger moaning about a specific company. What did I want to get? We watch TV, we have internet and we do have a land line. The land line is from a different vendor then the TV and the internet. I have decided that this makes no sense and I was going to get a bundle (no need to infer who this is, I just picked the generic bundle word as this is what I want to get) of all three services as this seems to save me money. I also want to not talk to people, I just want to click on a website when I feel like it and get it all sorted. I do think that is reality. I want to just do my shopping at 9.30pm while watching silly reruns on TV. Problem 1 - Bad links So, I'm an existing customer of the company I want to buy my bundle from. I go to the website, I click on offers. Turns out they are offers for new customers. After grumbling about how good they are, I click on offers for existing customers. Bummer, it goes to offers for new customers, so I click again on the link for offers for existing customers. No cigar... it just does not work. Big data solutions: 1) Do not show an existing customer the offers for new customers unless they are the same => This is only partially doable without login, but if a customer logs in the application should always know that this is an existing customer. But in general, imagine I do this from my home going through the internet service of this vendor to their domain... an instant filter should move me into the "existing customer route". 2) Flag dead or incorrect links => I've clicked the link for "existing customer offers" at least 3 times in under 5 seconds... Identifying patterns like this is easy in Hadoop and can very quickly make a list of potentially incorrect links. No need for realtime fixing, just the fact that this link can be pro-actively fixed across my entire web domain is a good thing. Preventative maintenance! Problem 2 - Purchase cannot be completed Apart from the fact that the browsing pattern to actually get to what I want is poorly designed, my purchase never gets past a specific point. In other words, I put something into my shopping cart and when I want to move on the application either crashes (with me going to an error page) or hangs or goes into something like chat. So I try again, and again and again. I think I tried this entire path (while being logged in!!) at least 10 times over the course of 20 minutes. I also clicked on the feedback button and, frustrated as I was, tried to explain this did not work... Big Data Solutions: 1) This web site does shopping cart analysis. I got an email next day stating I have things in my shopping cart, just click here to complete my purchase. After the above experience, this just added insult to my pain... 2) What should have happened, is a Hadoop job going over all logged in customers that are on the buy flow. It should flag anyone who is trying (multiple attempts from the same user to do the same thing), analyze the shopping card, the clicks to identify what the customers wants, his feedback provided (note: always own your own website feedback, never just farm this out!!) and in a short turn around time (30 minutes to 2 hours or so) email me with a link to complete my purchase. Not with a link to my shopping cart 12 hours later, but a link to actually achieve what I wanted... Why should this company go through the big data effort? I do believe this is relatively easy to do using our Oracle Event Processing and Big Data Appliance solutions combined. It is almost so simple (to my mind) that it makes no sense that this is not in place? But, now I am ranting... Why is this interesting? It is because of $$$$. After trying really hard, I mean I did this all in the evening, and again in the morning before going to work. I kept on failing, But I really wanted this to work... so an email that said, sorry, we noticed you tried to get a bundle (the log knows what I wanted, where I failed, so easy to generate), here is the link to click and complete your purchase. And here is 2 movies on us as an apology would have kept me as a customer, and got the additional $$$$ per month for the next couple of years. It would also lead to upsell on my phone package etc. Instead, I went to a completely different company, bought service from them. Lost money for company A, negative sentiment for company A and me telling this story at the water cooler so I'm influencing more people to think negatively about company A. All in all, a loss of easy money, a ding in sentiment and image where a relatively simple solution exists and can be in place on the software I describe routinely in this blog... For those who are coming to Openworld and maybe see value in solving the above, or are thinking of how to solve this, come visit us in Moscone North - Oracle Red Lounge or in the Engineered Systems Showcase.

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• How do I make an external hard drive keep the same drive letter permanently?

  - by andygrunt

  I have a desktop PC (2002 vintage) running Windows XP that I turn on about 2 or 3 times per week. I have a mains powered 250Gb Western Digital hard disk connected to it via USB. I always turn the hard disk on before the PC so it's up and running as the PC boots. When I first connected the external hard disk, the PC assigned it a letter ('i' if it matters) and I've installed software to it, created shortcuts to various files and folders on the disk using that letter. For years everything was fine then I would boot the PC and the hard disk was assigned a different letter. I'd then have to go into 'my computer/manage/disk management' and manually change the letter back to 'i'. If I then rebooted the PC, the hard disk would usually still be 'i' but after the next reboot would be some other random letter and I have to manually change it back to 'i'. This would go on for some time then there'd be periods when the it would always be 'i' then, for no apparent reason (no new devices added, for example), the drive letter would start changing again. At the moment it's in random drive letter mood so I thought I'd ask the following question... How do I assign the external hard disk to be 'i' permanently? Answer: Thanks Molly that seems to have done the trick (after a little fiddling) - slightly disappointed there wasn't a way to do it within Windows without installing something else though. For anyone else trying this, it wasn't completely straightforward so here's what happened with me. I installed USBDLM as per the instructions on its website. I guessed that I had to assign the first USB letter to i so replaced the 'Letter1=' lines to 'Letter=I' in the ini file. To test it, I rebooted the PC only to find it came back up with the display set to 640x480 in 16 colours. After some investigation, I re-installed the display drivers and rebooted and set the display back to its usual setting. The external hard disk now gets set to 'i' but I found I had to re-apply sharing status to it so it was seen from my laptop which is on the same network. The end result of all this is that it now does what I wanted although it does act as though the hard drive has just been plugged in a few seconds after the Windows desktop appears i.e. the little box appears with a progress bar as it searches through the contents of the 'new' hard drive and I eventually get a dialogue box saying 'This disk or device contains more than one type of content. What do you want Windows to do?' and lists options such as play media files, print the pictures or open folder to view the files. This is a tiny pain I wish didn't happen but not exactly a huge price to pay. Other than that - it seems to work fine :) Looks like a spoke too soon... Every time I reboot, I have to re-share the 'i' drive (which I didn't have to do before) so it can be seen by my laptop on the same network. Any ideas how to make that permanent?

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• FOUR questions to ask if you are implementing DATABASE-AS-A-SERVICE

  - by Sudip Datta

  During my ongoing tenure at Oracle, I have met all types of DBAs. Happy DBAs, unhappy DBAs, proud DBAs, risk-loving DBAs, cautious DBAs. These days, as Database-as-a-Service (DBaaS) becomes more mainstream, I find some complacent DBAs who are basking in their achievement of having implemented DBaaS. Some others, however, are not that happy. They grudgingly complain that they did not have much of a say in the implementation, they simply had to follow what their cloud architects (mostly infrastructure admins) offered them. In most cases it would be a database wrapped inside a VM that would be labeled as “Database as a Service”. In other cases, it would be existing brute-force automation simply exposed in a portal. As much as I think that there is more to DBaaS than those approaches and often get tempted to propose Enterprise Manager 12c, I try to be objective. Neither do I want to dampen the spirit of the happy ones, nor do I want to stoke the pain of the unhappy ones. As I mentioned in my previous post, I don’t deny vanilla automation could be useful. I like virtualization too for what it has helped us accomplish in terms of resource management, but we need to scrutinize its merit on a case-by-case basis and apply it meaningfully. For DBAs who either claim to have implemented DBaaS or are planning to do so, I simply want to provide four key questions to ponder about: 1. Does it make life easier for your end users? Database-as-a-Service can have several types of end users. Junior DBAs, QA Engineers, Developers- each having their own skillset. The objective of DBaaS is to make their life simple, so that they can focus on their core responsibilities without having to worry about additional stuff. For example, if you are a Developer using Oracle Application Express (APEX), you want to deal with schema, objects and PL/SQL code and not with datafiles or listener configuration. If you are a QA Engineer needing database copies for functional testing, you do not want to deal with underlying operating system patching and compliance issues. The question to ask, therefore, is, whether DBaaS makes life easier for those users. It is often convenient to give them VM shells to deal with a la Amazon EC2 IaaS, but is that what they really want? Is it a productive use of a developer's time if he needs to apply RPM errata to his Linux operating system. Asking him to keep the underlying operating system current is like making a guest responsible for a restaurant's decor. 2. Does it make life easier for your administrators? Cloud, in general, is supposed to free administrators from attending to mundane tasks like provisioning services for every single end user request. It is supposed to enable a readily consumable platform and enforce standardization in the process. For example, if a Service Catalog exposes DBaaS of specific database versions and configurations, it, by its very nature, enforces certain discipline and standardization within the IT environment. What if, instead of specific database configurations, cloud allowed each end user to create databases of their liking resulting in hundreds of version and patch levels and thousands of individual databases. Therefore the right question to ask is whether the unwanted consequence of DBaaS is OS and database sprawl. And if so, who is responsible for tracking them, backing them up, administering them? Studies have shown that these administrative overheads increase exponentially with new targets, and it could result in a management nightmare. That leads us to our next question. 3. Does it satisfy your Security Officers and Compliance Auditors? Compliance Auditors need to know who did what and when. They also want the cloud platform to be secure, so that end users have little freedom in tampering with it. Dealing with VM sprawl is not the easiest of challenges, let alone dealing with them as they keep getting reconfigured and moved around. This leads to the proverbial needle in the haystack problem, and all it needs is one needle to cause a serious compliance issue in the enterprise. Bottomline is, flexibility and agility should not come at the expense of compliance and it is very important to get the balance right. Can we have security and isolation without creating compliance challenges? Instead of a ‘one size fits all approach’ i.e. OS level isolation, can we think smartly about database isolation or schema based isolation? This is where the appropriate resource modeling needs to be applied. The usual systems management vendors out there with heterogeneous common-denominator approach have compromised on these semantics. If you follow Enterprise Manager’s DBaaS solution, you will see that we have considered different models, not precluding virtualization, for different customer use cases. The judgment to use virtual assemblies versus databases on physical RAC versus Schema-as-a-Service in a single database, should be governed by the need of the applications and not by putting compliance considerations in the backburner. 4. Does it satisfy your CIO? Finally, does it satisfy your higher ups? As the sponsor of cloud initiative, the CIO is expected to lead an IT transformation project, not merely a run-of-the-mill IT operations. Simply virtualizing server resources and delivering them through self-service is a good start, but hardly transformational. CIOs may appreciate the instant benefit from server consolidation, but studies have revealed that the ROI from consolidation would flatten out at 20-25%. The question would be: what next? As we go higher up in the stack, the need to virtualize, segregate and optimize shifts to those layers that are more palpable to the business users. As Sushil Kumar noted in his blog post, " the most important thing to note here is the enterprise private cloud is not just an IT project, rather it is a business initiative to create an IT setup that is more aligned with the needs of today's dynamic and highly competitive business environment." Business users could not care less about infrastructure consolidation or virtualization - they care about business agility and service level assurance. Last but not the least, lot of CIOs get miffed if we ask them to throw away their existing hardware investments for implementing DBaaS. In Oracle, we always emphasize on freedom of choosing a platform; hence Enterprise Manager’s DBaaS solution is platform neutral. It can work on any Operating System (that the agent is certified on) Oracle’s hardware as well as 3rd party hardware. As a parting note, I urge you to remember these 4 questions. Remember that your satisfaction as an implementer lies in the satisfaction of others.

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• My PC suddenly doesn't detect the primary drive (SSD)

  - by smoth190

  My computer has been working fine for months, and it worked today, but tonight I went to start it up to find that my OCZ Vertex 2 isn't being found. When I turn on my computer, the loading screen gets stuck at "Detecting IDE drives...". After a while, it keeps going and lists the drives it finds. The first one in the list should be my Vertex 2, but it just says "None". The computer proceeds to get stuck on "Loading operating system...", which is understandable because the drive with the OS is "gone". My first thought was drive failure, but every time drives have crashed on me, they're still detected--they just don't work. This drive is an SSD, it's pretty new, and I had no problems beforehand. I find it hard to believe it failed. I'm sure it's possible, but I hope this isn't the case. There has been nothing strange going on at all with my PC, it's been running perfect until now. I was just about to do my monthly dskchk and defrag today. I popped in my Windows 7 Home Premium disk and booted from it. When I launched the repair tool, it didn't list any operating systems (because the drive is 100% missing...). When I've had disks crash before, it still listed the OS, you just couldn't do anything with it. I tried to restore from an image, but I don't have any of those, either. I opened the command console and listed the drivers with wmic logicaldisk get name. Only C: and D: came up. C: was my 1TB storage driver (luckily, all my stuff is here--only the OS is on the SSD!) and D: was the disk driver. So I still had an MIA drive... The SSD didn't come with any driver disks, so I can't install drivers. If there's a way to do this from a CD I can burn with my other PC, please let me know. What the heck do I do? Although only the OS is on my SSD, a new SSD is expensive. I'll probably also have to buy a new copy of Windows (an upgrade would be nice, though...) because I've found it eats my registration key when my PC crashes (and my thousands of dollars of Adobe programs, I'll be on the phone with tech support for a week to get those keys back). And I'll lose my registry, all my settings, all sorts of other stuff that I'll spend weeks restoring. My computer is a pain in the butt to take out and open up, so if I can't fix it, I'll try fiddling with the plug or putting it into a new computer, but not right now. Any help is greatly appreciated! The day when they make crash-less drives will be the day I live without worry.

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• Maintenance plans love story

  - by Maria Zakourdaev

  There are about 200 QA and DEV SQL Servers out there.  There is a maintenance plan on many of them that performs a backup of all databases and removes the backup history files. First of all, I must admit that I’m no big fan of maintenance plans in particular or the SSIS packages in general.  In this specific case, if I ever need to change anything in the way backup is performed, such as the compression feature or perform some other change, I have to open each plan one by one. This is quite a pain. Therefore, I have decided to replace the maintenance plans with a stored procedure that will perform exactly the same thing.  Having such a procedure will allow me to open multiple server connections and just execute an ALTER PROCEDURE whenever I need to change anything in it. There is nothing like good ole T-SQL. The first challenge was to remove the unneeded maintenance plans. Of course, I didn’t want to do it server by server.  I found the procedure msdb.dbo.sp_maintplan_delete_plan, but it only has a parameter for the maintenance plan id and it has no other parameters, like plan name, which would have been much more useful. Now I needed to find the table that holds all maintenance plans on the server. You would think that it would be msdb.dbo.sysdbmaintplans but, unfortunately, regardless of the number of maintenance plans on the instance, it contains just one row.    After a while I found another table: msdb.dbo.sysmaintplan_subplans. It contains the plan id that I was looking for, in the plan_id column and well as the agent’s job id which is executing the plan’s package: That was all I needed and the rest turned out to be quite easy.  Here is a script that can be executed against hundreds of servers from a multi-server query window to drop the specific maintenance plans. DECLARE @PlanID uniqueidentifier   SELECT @PlanID = plan_id FROM msdb.dbo.sysmaintplan_subplans Where name like ‘BackupPlan%’   EXECUTE msdb.dbo.sp_maintplan_delete_plan @plan_id=@PlanID   The second step was to create a procedure that will perform  all of the old maintenance plan tasks: create a folder for each database, backup all databases on the server and clean up the old files. The script is below. Enjoy.   ALTER PROCEDURE BackupAllDatabases                                   @PrintMode BIT = 1 AS BEGIN          DECLARE @BackupLocation VARCHAR(500)        DECLARE @PurgeAferDays INT        DECLARE @PurgingDate VARCHAR(30)        DECLARE @SQLCmd  VARCHAR(MAX)        DECLARE @FileName  VARCHAR(100)               SET @PurgeAferDays = -14        SET @BackupLocation = '\\central_storage_servername\BACKUPS\'+@@servername               SET @PurgingDate = CONVERT(VARCHAR(19), DATEADD (dd,@PurgeAferDays,GETDATE()),126)               SET @FileName = '?_full_'+                      + REPLACE(CONVERT(VARCHAR(19), GETDATE(),126),':','-')                      +'.bak';          SET @SQLCmd = '               IF ''?'' <> ''tempdb'' BEGIN                      EXECUTE master.dbo.xp_create_subdir N'''+@BackupLocation+'\?\'' ;                        BACKUP DATABASE ? TO  DISK = N'''+@BackupLocation+'\?\'+@FileName+'''                      WITH NOFORMAT, NOINIT,  SKIP, REWIND, NOUNLOAD, COMPRESSION,  STATS = 10 ;                        EXECUTE master.dbo.xp_delete_file 0,N'''+@BackupLocation+'\?\'',N''bak'',N'''+@PurgingDate+''',1;               END'          IF @PrintMode = 1 BEGIN               PRINT @SQLCmd        END               EXEC sp_MSforeachdb @SQLCmd        END

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• ASP.NET MVC 2 / Localization / Dynamic Default Value?

  - by cyberblast

  Hello In an ASP.NET MVC 2 application, i'm having a route like this: routes.MapRoute( "Default", // Route name "{lang}/{controller}/{action}/{id}", // URL with parameters new // Parameter defaults { controller = "Home", action = "Index", lang = "de", id = UrlParameter.Optional }, new { lang = new AllowedValuesRouteConstraint(new string[] { "de", "en", "fr", "it" }, StringComparison.InvariantCultureIgnoreCase) } Now, basically I would like to set the thread's culture according the language passed in. But there is one exception: If the user requests the page for the first time, like calling "http://www.mysite.com" I want to set the initial language if possible to the one "preferred by the browser". How can I distinguish in an early procesing stage (like global.asax), if the default parameter has been set because of the default value or mentioned explicit through the URL? (I would prefer a solution where the request URL is not getting parsed). Is there a way to dynamically provide a default-value for a paramter? Something like a hook? Or where can I override the default value (good application event?). This is the code i'm actually experimenting with: protected void Application_AcquireRequestState(object sender, EventArgs e) { string activeLanguage; string[] validLanguages; string defaultLanguage; string browsersPreferredLanguage; try { HttpContextBase contextBase = new HttpContextWrapper(Context); RouteData activeRoute = RouteTable.Routes.GetRouteData(new HttpContextWrapper(Context)); if (activeRoute == null) { return; } activeLanguage = activeRoute.GetRequiredString("lang"); Route route = (Route)activeRoute.Route; validLanguages = ((AllowedValuesRouteConstraint)route.Constraints["lang"]).AllowedValues; defaultLanguage = route.Defaults["lang"].ToString(); browsersPreferredLanguage = GetBrowsersPreferredLanguage(); //TODO: Better way than parsing the url bool defaultInitialized = contextBase.Request.Url.ToString().IndexOf(string.Format("/{0}/", defaultLanguage), StringComparison.InvariantCultureIgnoreCase) > -1; string languageToActivate = defaultLanguage; if (!defaultInitialized) { if (validLanguages.Contains(browsersPreferredLanguage, StringComparer.InvariantCultureIgnoreCase)) { languageToActivate = browsersPreferredLanguage; } } //TODO: Where and how to overwrtie the default value that it gets passed to the controller? contextBase.RewritePath(contextBase.Request.Path.Replace("/de/", "/en/")); SetLanguage(languageToActivate); } catch (Exception ex) { //TODO: Log Console.WriteLine(ex.Message); } } protected string GetBrowsersPreferredLanguage() { string acceptedLang = string.Empty; if (HttpContext.Current.Request.UserLanguages != null && HttpContext.Current.Request.UserLanguages.Length > 0) { acceptedLang = HttpContext.Current.Request.UserLanguages[0].Substring(0, 2); } return acceptedLang; } protected void SetLanguage(string languageToActivate) { CultureInfo cultureInfo = new CultureInfo(languageToActivate); if (!Thread.CurrentThread.CurrentUICulture.TwoLetterISOLanguageName.Equals(languageToActivate, StringComparison.InvariantCultureIgnoreCase)) { Thread.CurrentThread.CurrentUICulture = cultureInfo; } if (!Thread.CurrentThread.CurrentCulture.TwoLetterISOLanguageName.Equals(languageToActivate, StringComparison.InvariantCultureIgnoreCase)) { Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(cultureInfo.Name); } } The RouteConstraint to reproduce the sample: public class AllowedValuesRouteConstraint : IRouteConstraint { private string[] _allowedValues; private StringComparison _stringComparism; public string[] AllowedValues { get { return _allowedValues; } } public AllowedValuesRouteConstraint(string[] allowedValues, StringComparison stringComparism) { _allowedValues = allowedValues; _stringComparism = stringComparism; } public AllowedValuesRouteConstraint(string[] allowedValues) { _allowedValues = allowedValues; _stringComparism = StringComparison.InvariantCultureIgnoreCase; } public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection) { if (_allowedValues != null) { return _allowedValues.Any(a => a.Equals(values[parameterName].ToString(), _stringComparism)); } else { return false; } } } Can someone help me out with that problem? Thanks, Martin

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• Incremental PCA

  - by smichak

  Hi, Lately, I've been looking into an implementation of an incremental PCA algorithm in python - I couldn't find something that would meet my needs so I did some reading and implemented an algorithm I found in some paper. Here is the module's code - the relevant paper on which it is based is mentioned in the module's documentation. I would appreciate any feedback from people who are interested in this. Micha #!/usr/bin/env python """ Incremental PCA calculation module. Based on P.Hall, D. Marshall and R. Martin "Incremental Eigenalysis for Classification" which appeared in British Machine Vision Conference, volume 1, pages 286-295, September 1998. Principal components are updated sequentially as new observations are introduced. Each new observation (x) is projected on the eigenspace spanned by the current principal components (U) and the residual vector (r = x - U(U.T*x)) is used as a new principal component (U' = [U r]). The new principal components are then rotated by a rotation matrix (R) whose columns are the eigenvectors of the transformed covariance matrix (D=U'.T*C*U) to yield p + 1 principal components. From those, only the first p are selected. """ __author__ = "Micha Kalfon" import numpy as np _ZERO_THRESHOLD = 1e-9 # Everything below this is zero class IPCA(object): """Incremental PCA calculation object. General Parameters: m - Number of variables per observation n - Number of observations p - Dimension to which the data should be reduced """ def __init__(self, m, p): """Creates an incremental PCA object for m-dimensional observations in order to reduce them to a p-dimensional subspace. @param m: Number of variables per observation. @param p: Number of principle components. @return: An IPCA object. """ self._m = float(m) self._n = 0.0 self._p = float(p) self._mean = np.matrix(np.zeros((m , 1), dtype=np.float64)) self._covariance = np.matrix(np.zeros((m, m), dtype=np.float64)) self._eigenvectors = np.matrix(np.zeros((m, p), dtype=np.float64)) self._eigenvalues = np.matrix(np.zeros((1, p), dtype=np.float64)) def update(self, x): """Updates with a new observation vector x. @param x: Next observation as a column vector (m x 1). """ m = self._m n = self._n p = self._p mean = self._mean C = self._covariance U = self._eigenvectors E = self._eigenvalues if type(x) is not np.matrix or x.shape != (m, 1): raise TypeError('Input is not a matrix (%d, 1)' % int(m)) # Update covariance matrix and mean vector and centralize input around # new mean oldmean = mean mean = (n*mean + x) / (n + 1.0) C = (n*C + x*x.T + n*oldmean*oldmean.T - (n+1)*mean*mean.T) / (n + 1.0) x -= mean # Project new input on current p-dimensional subspace and calculate # the normalized residual vector g = U.T*x r = x - (U*g) r = (r / np.linalg.norm(r)) if not _is_zero(r) else np.zeros_like(r) # Extend the transformation matrix with the residual vector and find # the rotation matrix by solving the eigenproblem DR=RE U = np.concatenate((U, r), 1) D = U.T*C*U (E, R) = np.linalg.eigh(D) # Sort eigenvalues and eigenvectors from largest to smallest to get the # rotation matrix R sorter = list(reversed(E.argsort(0))) E = E[sorter] R = R[:,sorter] # Apply the rotation matrix U = U*R # Select only p largest eigenvectors and values and update state self._n += 1.0 self._mean = mean self._covariance = C self._eigenvectors = U[:, 0:p] self._eigenvalues = E[0:p] @property def components(self): """Returns a matrix with the current principal components as columns. """ return self._eigenvectors @property def variances(self): """Returns a list with the appropriate variance along each principal component. """ return self._eigenvalues def _is_zero(x): """Return a boolean indicating whether the given vector is a zero vector up to a threshold. """ return np.fabs(x).min() < _ZERO_THRESHOLD if __name__ == '__main__': import sys def pca_svd(X): X = X - X.mean(0).repeat(X.shape[0], 0) [_, _, V] = np.linalg.svd(X) return V N = 1000 obs = np.matrix([np.random.normal(size=10) for _ in xrange(N)]) V = pca_svd(obs) print V[0:2] pca = IPCA(obs.shape[1], 2) for i in xrange(obs.shape[0]): x = obs[i,:].transpose() pca.update(x) U = pca.components print U

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• Design Question - how do you break the dependency between classes using an interface?

  - by Seth Spearman

  Hello, I apologize in advance but this will be a long question. I'm stuck. I am trying to learn unit testing, C#, and design patterns - all at once. (Maybe that's my problem.) As such I am reading the Art of Unit Testing (Osherove), and Clean Code (Martin), and Head First Design Patterns (O'Reilly). I am just now beginning to understand delegates and events (which you would see if you were to troll my SO questions of recent). I still don't quite get lambdas. To contextualize all of this I have given myself a learning project I am calling goAlarms. I have an Alarm class with members you'd expect (NextAlarmTime, Name, AlarmGroup, Event Trigger etc.) I wanted the "Timer" of the alarm to be extensible so I created an IAlarmScheduler interface as follows... public interface AlarmScheduler { Dictionary<string,Alarm> AlarmList { get; } void Startup(); void Shutdown(); void AddTrigger(string triggerName, string groupName, Alarm alarm); void RemoveTrigger(string triggerName); void PauseTrigger(string triggerName); void ResumeTrigger(string triggerName); void PauseTriggerGroup(string groupName); void ResumeTriggerGroup(string groupName); void SetSnoozeTrigger(string triggerName, int duration); void SetNextOccurrence (string triggerName, DateTime nextOccurrence); } This IAlarmScheduler interface define a component that will RAISE an alarm (Trigger) which will bubble up to my Alarm class and raise the Trigger Event of the alarm itself. It is essentially the "Timer" component. I have found that the Quartz.net component is perfectly suited for this so I have created a QuartzAlarmScheduler class which implements IAlarmScheduler. All that is fine. My problem is that the Alarm class is abstract and I want to create a lot of different KINDS of alarm. For example, I already have a Heartbeat alarm (triggered every (int) interval of minutes), AppointmentAlarm (triggered on set date and time), Daily Alarm (triggered every day at X) and perhaps others. And Quartz.NET is perfectly suited to handle this. My problem is a design problem. I want to be able to instantiate an alarm of any kind without my Alarm class (or any derived classes) knowing anything about Quartz. The problem is that Quartz has awesome factories that return just the right setup for the Triggers that will be needed by my Alarm classes. So, for example, I can get a Quartz trigger by using TriggerUtils.MakeMinutelyTrigger to create a trigger for the heartbeat alarm described above. Or TriggerUtils.MakeDailyTrigger for the daily alarm. I guess I could sum it up this way. Indirectly or directly I want my alarm classes to be able to consume the TriggerUtils.Make* classes without knowing anything about them. I know that is a contradiction, but that is why I am asking the question. I thought about putting a delegate field into the alarm which would be assigned one of these Make method but by doing that I am creating a hard dependency between alarm and Quartz which I want to avoid for both unit testing purposes and design purposes. I thought of using a switch for the type in QuartzAlarmScheduler per here but I know it is bad design and I am trying to learn good design. If I may editorialize a bit. I've decided that coding (predefined) classes is easy. Design is HARD...in fact, really hard and I am really fighting feeling stupid right now. I guess I want to know if you really smart people took a while to really understand and master this stuff or should I feel stupid (as I do) because I haven't grasped it better in the couple of weeks/months I have been studying. You guys are awesome and thanks in advance for your answers. Seth

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• Is it possible to embed Cockburn style textual UML Use Case content in the code base to improve code

  - by fooledbyprimes

  experimenting with Cockburn use cases in code I was writing some complicated UI code. I decided to employ Cockburn use cases with fish,kite,and sea levels (discussed by Martin Fowler in his book 'UML Distilled'). I wrapped Cockburn use cases in static C# objects so that I could test logical conditions against static constants which represented steps in a UI workflow. The idea was that you could read the code and know what it was doing because the wrapped objects and their public contants gave you ENGLISH use cases via namespaces. Also, I was going to use reflection to pump out error messages that included the described use cases. The idea is that the stack trace could include some UI use case steps IN ENGLISH.... It turned out to be a fun way to achieve a mini,psuedo light-weight Domain Language but without having to write a DSL compiler. So my question is whether or not this is a good way to do this? Has anyone out there ever done something similar? c# example snippets follow Assume we have some aspx page which has 3 user controls (with lots of clickable stuff). User must click on stuff in one particular user control (possibly making some kind of selection) and then the UI must visually cue the user that the selection was successful. Now, while that item is selected, the user must browse through a gridview to find an item within one of the other user controls and then select something. This sounds like an easy thing to manage but the code can get ugly. In my case, the user controls all sent event messages which were captured by the main page. This way, the page acted like a central processor of UI events and could keep track of what happens when the user is clicking around. So, in the main aspx page, we capture the first user control's event. using MyCompany.MyApp.Web.UseCases; protected void MyFirstUserControl_SomeUIWorkflowRequestCommingIn(object sender, EventArgs e) { // some code here to respond and make "state" changes or whatever // // blah blah blah // finally we have this (how did we know to call fish level method?? because we knew when we wrote the code to send the event in the user control) UpdateUserInterfaceOnFishLevelUseCaseGoalSuccess(FishLevel.SomeNamedUIWorkflow.SelectedItemForPurchase) } protected void UpdateUserInterfaceOnFishLevelGoalSuccess(FishLevel.SomeNamedUIWorkflow goal) { switch (goal) { case FishLevel.SomeNamedUIWorkflow.NewMasterItemSelected: //call some UI related methods here including methods for the other user controls if necessary.... break; case FishLevel.SomeNamedUIWorkFlow.DrillDownOnDetails: //call some UI related methods here including methods for the other user controls if necessary.... break; case FishLevel.SomeNamedUIWorkFlow.CancelMultiSelect: //call some UI related methods here including methods for the other user controls if necessary.... break; // more cases... } } } //also we have protected void UpdateUserInterfaceOnSeaLevelGoalSuccess(SeaLevel.SomeNamedUIWorkflow goal) { switch (goal) { case SeaLevel.CheckOutWorkflow.ChangedCreditCard: // do stuff // more cases... } } } So, in the MyCompany.MyApp.Web.UseCases namespace we might have code like this: class SeaLevel... class FishLevel... class KiteLevel... The workflow use cases embedded in the classes could be inner classes or static methods or enumerations or whatever gives you the cleanest namespace. I can't remember what I did originally but you get the picture.

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• Increasing speed of python code

  - by Curious2learn

  Hi, I have some python code that has many classes. I used cProfile to find that the total time to run the program is 68 seconds. I found that the following function in a class called Buyers takes about 60 seconds of those 68 seconds. I have to run the program about 100 times, so any increase in speed will help. Can you suggest ways to increase the speed by modifying the code? If you need more information that will help, please let me know. def qtyDemanded(self, timePd, priceVector): '''Returns quantity demanded in period timePd. In addition, also updates the list of customers and non-customers. Inputs: timePd and priceVector Output: count of people for whom priceVector[-1] < utility ''' ## Initialize count of customers to zero ## Set self.customers and self.nonCustomers to empty lists price = priceVector[-1] count = 0 self.customers = [] self.nonCustomers = [] for person in self.people: if person.utility >= price: person.customer = 1 self.customers.append(person) else: person.customer = 0 self.nonCustomers.append(person) return len(self.customers) self.people is a list of person objects. Each person has customer and utility as its attributes. EDIT - responsed added ------------------------------------- Thanks so much for the suggestions. Here is the response to some questions and suggestions people have kindly made. I have not tried them all, but will try others and write back later. (1) @amber - the function is accessed 80,000 times. (2) @gnibbler and others - self.people is a list of Person objects in memory. Not connected to a database. (3) @Hugh Bothwell cumtime taken by the original function - 60.8 s (accessed 80000 times) cumtime taken by the new function with local function aliases as suggested - 56.4 s (accessed 80000 times) (4) @rotoglup and @Martin Thomas I have not tried your solutions yet. I need to check the rest of the code to see the places where I use self.customers before I can make the change of not appending the customers to self.customers list. But I will try this and write back. (5) @TryPyPy - thanks for your kind offer to check the code. Let me first read a little on the suggestions you have made to see if those will be feasible to use. EDIT 2 Some suggested that since I am flagging the customers and noncustomers in the self.people, I should try without creating separate lists of self.customers and self.noncustomers using append. Instead, I should loop over the self.people to find the number of customers. I tried the following code and timed both functions below f_w_append and f_wo_append. I did find that the latter takes less time, but it is still 96% of the time taken by the former. That is, it is a very small increase in the speed. @TryPyPy - The following piece of code is complete enough to check the bottleneck function, in case your offer is still there to check it with other compilers. Thanks again to everyone who replied. import numpy class person(object): def __init__(self, util): self.utility = util self.customer = 0 class population(object): def __init__(self, numpeople): self.people = [] self.cus = [] self.noncus = [] numpy.random.seed(1) utils = numpy.random.uniform(0, 300, numpeople) for u in utils: per = person(u) self.people.append(per) popn = population(300) def f_w_append(): '''Function with append''' P = 75 cus = [] noncus = [] for per in popn.people: if per.utility >= P: per.customer = 1 cus.append(per) else: per.customer = 0 noncus.append(per) return len(cus) def f_wo_append(): '''Function without append''' P = 75 for per in popn.people: if per.utility >= P: per.customer = 1 else: per.customer = 0 numcustomers = 0 for per in popn.people: if per.customer == 1: numcustomers += 1 return numcustomers

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• How do I resolve "Unable to resolve attribute [organizationType.id] against path" exception?

  - by Dave

  I'm using Spring 3.1.1.RELEASE, Hibernate 4.1.0.Final, JUnit 4.8, and JPA 2.0 (hibernate-jpa-2.0-api). I'm trying to write a query and search based on fields of member fields. What I mean is I have this entity … @GenericGenerator(name = "uuid-strategy", strategy = "uuid.hex") @Entity @Table(name = "cb_organization", uniqueConstraints = {@UniqueConstraint(columnNames={"organization_id"})}) public class Organization implements Serializable { @Id @NotNull @GeneratedValue(generator = "uuid-strategy") @Column(name = "id") /* the database id of the Organization */ private String id; @ManyToOne @JoinColumn(name = "state_id", nullable = true, updatable = false) /* the State for the organization */ private State state; @ManyToOne @JoinColumn(name = "country_id", nullable = false, updatable = false) /* The country the Organization is in */ private Country country; @ManyToOne(optional = false) @JoinColumn(name = "organization_type_id", nullable = false, updatable = false) /* The type of the Organization */ private OrganizationType organizationType; Notice the members "organizationType," "state," and "country," which are all objects. I wish to build a query based on their id fields. This code @Override public List<Organization> findByOrgTypesCountryAndState(Set<String> organizationTypes, String countryId, String stateId) { CriteriaBuilder builder = entityManager.getCriteriaBuilder(); CriteriaQuery<Organization> criteria = builder.createQuery(Organization.class); Root<Organization> org = criteria.from(Organization.class); criteria.select(org).where(builder.and(org.get("organizationType.id").in(organizationTypes), builder.equal(org.get("state.id"), stateId), builder.equal(org.get("country.id"), countryId))); return entityManager.createQuery(criteria).getResultList(); } is throwing the exception below. How do I heal the pain? java.lang.IllegalArgumentException: Unable to resolve attribute [organizationType.id] against path at org.hibernate.ejb.criteria.path.AbstractPathImpl.unknownAttribute(AbstractPathImpl.java:116) at org.hibernate.ejb.criteria.path.AbstractPathImpl.locateAttribute(AbstractPathImpl.java:221) at org.hibernate.ejb.criteria.path.AbstractPathImpl.get(AbstractPathImpl.java:192) at org.mainco.subco.organization.repo.OrganizationDaoImpl.findByOrgTypesCountryAndState(OrganizationDaoImpl.java:248) at org.mainco.subco.organization.repo.OrganizationDaoTest.testFindByOrgTypesCountryAndState(OrganizationDaoTest.java:55) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20) at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74) at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71) at org.junit.runners.ParentRunner.run(ParentRunner.java:236) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

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• NoSQL with MongoDB, NoRM and ASP.NET MVC

  - by shiju

   In this post, I will give an introduction to how to work on NoSQL and document database with MongoDB , NoRM and ASP.Net MVC 2. NoSQL and Document Database The NoSQL movement is getting big attention in this year and people are widely talking about document databases and NoSQL along with web application scalability. According to Wikipedia, "NoSQL is a movement promoting a loosely defined class of non-relational data stores that break with a long history of relational databases. These data stores may not require fixed table schemas, usually avoid join operations and typically scale horizontally. Academics and papers typically refer to these databases as structured storage". Document databases are schema free so that you can focus on the problem domain and don't have to worry about updating the schema when your domain is evolving. This enables truly a domain driven development. One key pain point of relational database is the synchronization of database schema with your domain entities when your domain is evolving.There are lots of NoSQL implementations are available and both CouchDB and MongoDB got my attention. While evaluating both CouchDB and MongoDB, I found that CouchDB can’t perform dynamic queries and later I picked MongoDB over CouchDB. There are many .Net drivers available for MongoDB document database. MongoDB MongoDB is an open source, scalable, high-performance, schema-free, document-oriented database written in the C++ programming language. It has been developed since October 2007 by 10gen. MongoDB stores your data as binary JSON (BSON) format . MongoDB has been getting a lot of attention and you can see the some of the list of production deployments from here - http://www.mongodb.org/display/DOCS/Production+Deployments NoRM – C# driver for MongoDB NoRM is a C# driver for MongoDB with LINQ support. NoRM project is available on Github at http://github.com/atheken/NoRM. Demo with ASP.NET MVC I will show a simple demo with MongoDB, NoRM and ASP.NET MVC. To work with MongoDB and  NoRM, do the following steps Download the MongoDB databse For Windows 32 bit, download from http://downloads.mongodb.org/win32/mongodb-win32-i386-1.4.1.zip  and for Windows 64 bit, download  from http://downloads.mongodb.org/win32/mongodb-win32-x86_64-1.4.1.zip . The zip contains the mongod.exe for run the server and mongo.exe for the client Download the NorM driver for MongoDB at http://github.com/atheken/NoRM Create a directory call C:\data\db. This is the default location of MongoDB database. You can override the behavior. Run C:\Mongo\bin\mongod.exe. This will start the MongoDb server Now I am going to demonstrate how to program with MongoDb and NoRM in an ASP.NET MVC application.Let’s write a domain class public class Category {            [MongoIdentifier]public ObjectId Id { get; set; } [Required(ErrorMessage = "Name Required")][StringLength(25, ErrorMessage = "Must be less than 25 characters")]public string Name { get; set;}public string Description { get; set; }}  ObjectId is a NoRM type that represents a MongoDB ObjectId. NoRM will automatically update the Id becasue it is decorated by the MongoIdentifier attribute. The next step is to create a mongosession class. This will do the all interactions to the MongoDB. internal class MongoSession<TEntity> : IDisposable{    private readonly MongoQueryProvider provider;     public MongoSession()    {        this.provider = new MongoQueryProvider("Expense");    }     public IQueryable<TEntity> Queryable    {        get { return new MongoQuery<TEntity>(this.provider); }    }     public MongoQueryProvider Provider    {        get { return this.provider; }    }     public void Add<T>(T item) where T : class, new()    {        this.provider.DB.GetCollection<T>().Insert(item);    }     public void Dispose()    {        this.provider.Server.Dispose();     }    public void Delete<T>(T item) where T : class, new()    {        this.provider.DB.GetCollection<T>().Delete(item);    }     public void Drop<T>()    {        this.provider.DB.DropCollection(typeof(T).Name);    }     public void Save<T>(T item) where T : class,new()    {        this.provider.DB.GetCollection<T>().Save(item);                }  }    The MongoSession constrcutor will create an instance of MongoQueryProvider that supports the LINQ expression and also create a database with name "Expense". If database is exists, it will use existing database, otherwise it will create a new databse with name  "Expense". The Save method can be used for both Insert and Update operations. If the object is new one, it will create a new record and otherwise it will update the document with given ObjectId.  Let’s create ASP.NET MVC controller actions for CRUD operations for the domain class Category public class CategoryController : Controller{ //Index - Get the category listpublic ActionResult Index(){    using (var session = new MongoSession<Category>())    {        var categories = session.Queryable.AsEnumerable<Category>();        return View(categories);    }} //edit a single category[HttpGet]public ActionResult Edit(ObjectId id) {     using (var session = new MongoSession<Category>())    {        var category = session.Queryable              .Where(c => c.Id == id)              .FirstOrDefault();         return View("Save",category);    } }// GET: /Category/Create[HttpGet]public ActionResult Create(){    var category = new Category();    return View("Save", category);}//insert or update a category[HttpPost]public ActionResult Save(Category category){    if (!ModelState.IsValid)    {        return View("Save", category);    }    using (var session = new MongoSession<Category>())    {        session.Save(category);        return RedirectToAction("Index");    } }//Delete category[HttpPost]public ActionResult Delete(ObjectId Id){    using (var session = new MongoSession<Category>())    {        var category = session.Queryable              .Where(c => c.Id == Id)              .FirstOrDefault();        session.Delete(category);        var categories = session.Queryable.AsEnumerable<Category>();        return PartialView("CategoryList", categories);    } }        }  You can easily work on MongoDB with NoRM and can use with ASP.NET MVC applications. I have created a repository on CodePlex at http://mongomvc.codeplex.com and you can download the source code of the ASP.NET MVC application from here

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• Complete Guide to Symbolic Links (symlinks) on Windows or Linux

  - by Matthew Guay

  Want to easily access folders and files from different folders without maintaining duplicate copies?  Here’s how you can use Symbolic Links to link anything in Windows 7, Vista, XP, and Ubuntu. So What Are Symbolic Links Anyway? Symbolic links, otherwise known as symlinks, are basically advanced shortcuts. You can create symbolic links to individual files or folders, and then these will appear like they are stored in the folder with the symbolic link even though the symbolic link only points to their real location. There are two types of symbolic links: hard and soft. Soft symbolic links work essentially the same as a standard shortcut.  When you open a soft link, you will be redirected to the folder where the files are stored.  However, a hard link makes it appear as though the file or folder actually exists at the location of the symbolic link, and your applications won’t know any different. Thus, hard links are of the most interest in this article. Why should I use Symbolic Links? There are many things we use symbolic links for, so here’s some of the top uses we can think of: Sync any folder with Dropbox – say, sync your Pidgin Profile Across Computers Move the settings folder for any program from its original location Store your Music/Pictures/Videos on a second hard drive, but make them show up in your standard Music/Pictures/Videos folders so they’ll be detected my your media programs (Windows 7 Libraries can also be good for this) Keep important files accessible from multiple locations And more! If you want to move files to a different drive or folder and then symbolically link them, follow these steps: Close any programs that may be accessing that file or folder Move the file or folder to the new desired location Follow the correct instructions below for your operating system to create the symbolic link. Caution: Make sure to never create a symbolic link inside of a symbolic link. For instance, don’t create a symbolic link to a file that’s contained in a symbolic linked folder. This can create a loop, which can cause millions of problems you don’t want to deal with. Seriously. Create Symlinks in Any Edition of Windows in Explorer Creating symlinks is usually difficult, but thanks to the free Link Shell Extension, you can create symbolic links in all modern version of Windows pain-free.  You need to download both Visual Studio 2005 redistributable, which contains the necessary prerequisites, and Link Shell Extension itself (links below).  Download the correct version (32 bit or 64 bit) for your computer. Run and install the Visual Studio 2005 Redistributable installer first. Then install the Link Shell Extension on your computer. Your taskbar will temporally disappear during the install, but will quickly come back. Now you’re ready to start creating symbolic links.  Browse to the folder or file you want to create a symbolic link from.  Right-click the folder or file and select Pick Link Source. To create your symlink, right-click in the folder you wish to save the symbolic link, select “Drop as…”, and then choose the type of link you want.  You can choose from several different options here; we chose the Hardlink Clone.  This will create a hard link to the file or folder we selected.  The Symbolic link option creates a soft link, while the smart copy will fully copy a folder containing symbolic links without breaking them.  These options can be useful as well.   Here’s our hard-linked folder on our desktop.  Notice that the folder looks like its contents are stored in Desktop\Downloads, when they are actually stored in C:\Users\Matthew\Desktop\Downloads.  Also, when links are created with the Link Shell Extension, they have a red arrow on them so you can still differentiate them. And, this works the same way in XP as well. Symlinks via Command Prompt Or, for geeks who prefer working via command line, here’s how you can create symlinks in Command Prompt in Windows 7/Vista and XP. In Windows 7/Vista In Windows Vista and 7, we’ll use the mklink command to create symbolic links.  To use it, we have to open an administrator Command Prompt.  Enter “command” in your start menu search, right-click on Command Prompt, and select “Run as administrator”. To create a symbolic link, we need to enter the following in command prompt: mklink /prefix link_path file/folder_path First, choose the correct prefix.  Mklink can create several types of links, including the following: /D – creates a soft symbolic link, which is similar to a standard folder or file shortcut in Windows.  This is the default option, and mklink will use it if you do not enter a prefix. /H – creates a hard link to a file /J – creates a hard link to a directory or folder So, once you’ve chosen the correct prefix, you need to enter the path you want for the symbolic link, and the path to the original file or folder.  For example, if I wanted a folder in my Dropbox folder to appear like it was also stored in my desktop, I would enter the following: mklink /J C:\Users\Matthew\Desktop\Dropbox C:\Users\Matthew\Documents\Dropbox Note that the first path was to the symbolic folder I wanted to create, while the second path was to the real folder. Here, in this command prompt screenshot, you can see that I created a symbolic link of my Music folder to my desktop.   And here’s how it looks in Explorer.  Note that all of my music is “really” stored in C:\Users\Matthew\Music, but here it looks like it is stored in C:\Users\Matthew\Desktop\Music. If your path has any spaces in it, you need to place quotes around it.  Note also that the link can have a different name than the file it links to.  For example, here I’m going to create a symbolic link to a document on my desktop: mklink /H “C:\Users\Matthew\Desktop\ebook.pdf”  “C:\Users\Matthew\Downloads\Before You Call Tech Support.pdf” Don’t forget the syntax: mklink /prefix link_path Target_file/folder_path In Windows XP Windows XP doesn’t include built-in command prompt support for symbolic links, but we can use the free Junction tool instead.  Download Junction (link below), and unzip the folder.  Now open Command Prompt (click Start, select All Programs, then Accessories, and select Command Prompt), and enter cd followed by the path of the folder where you saved Junction. Junction only creates hard symbolic links, since you can use shortcuts for soft ones.  To create a hard symlink, we need to enter the following in command prompt: junction –s link_path file/folder_path As with mklink in Windows 7 or Vista, if your file/folder path has spaces in it make sure to put quotes around your paths.  Also, as usual, your symlink can have a different name that the file/folder it points to. Here, we’re going to create a symbolic link to our My Music folder on the desktop.  We entered: junction -s “C:\Documents and Settings\Administrator\Desktop\Music” “C:\Documents and Settings\Administrator\My Documents\My Music” And here’s the contents of our symlink.  Note that the path looks like these files are stored in a Music folder directly on the Desktop, when they are actually stored in My Documents\My Music.  Once again, this works with both folders and individual files. Please Note: Junction would work the same in Windows 7 or Vista, but since they include a built-in symbolic link tool we found it better to use it on those versions of Windows. Symlinks in Ubuntu Unix-based operating systems have supported symbolic links since their inception, so it is straightforward to create symbolic links in Linux distros such as Ubuntu.  There’s no graphical way to create them like the Link Shell Extension for Windows, so we’ll just do it in Terminal. Open terminal (open the Applications menu, select Accessories, and then click Terminal), and enter the following: ln –s file/folder_path link_path Note that this is opposite of the Windows commands; you put the source for the link first, and then the path second. For example, let’s create a symbolic link of our Pictures folder in our Desktop.  To do this, we entered: ln -s /home/maguay/Pictures /home/maguay/Desktop   Once again, here is the contents of our symlink folder.  The pictures look as if they’re stored directly in a Pictures folder on the Desktop, but they are actually stored in maguay\Pictures. Delete Symlinks Removing symbolic links is very simple – just delete the link!  Most of the command line utilities offer a way to delete a symbolic link via command prompt, but you don’t need to go to the trouble.   Conclusion Symbolic links can be very handy, and we use them constantly to help us stay organized and keep our hard drives from overflowing.  Let us know how you use symbolic links on your computers! Download Link Shell Extension for Windows 7, Vista, and XP Download Junction for XP Similar Articles Productive Geek Tips Using Symlinks in Windows VistaHow To Figure Out Your PC’s Host Name From the Command PromptInstall IceWM on Ubuntu LinuxAdd Color Coding to Windows 7 Media Center Program GuideSync Your Pidgin Profile Across Multiple PCs with Dropbox TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Gadfly is a cool Twitter/Silverlight app Enable DreamScene in Windows 7 Microsoft’s “How Do I ?” Videos Home Networks – How do they look like & the problems they cause Check Your IMAP Mail Offline In Thunderbird Follow Finder Finds You Twitter Users To Follow

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• Fitting it together, database, reporting, applications in C#

  - by alvonellos

  Introduction Preamble I was hesitant to post this, since it's an application whose intricate details are defined elsewhere, and answers may not be helpful to others. Within the past few weeks (I was actually going to write a blog post about this after I finished) I've discovered that the barrier I'm encountering is one that's actually quite common for newer developers. This question is not so much about a specific thing as it is about piecing those things together. I've searched the internet far and wide, and found many tutorials on how to create applications that are kind of similar to what I'm looking for. I've also looked at hiring another, more experienced, developer to help me along, but all I've gotten are unqualified candidates that don't have the experience necessary and won't take care of the client or project like I will. I'd rather have the project never transpire than to release a solution that is half-baked. I've asked professors at my school, but they've not turned up answers to my question. I'm an experienced developer, and I've written many applications that are -- very abstractly -- close to what I'm doing, but my experiences from those applications aren't giving me enough leverage to solve this particular problem. I just hope that posting this article isn't a mistake for me to write. Project Description I have a project I'm working on for a client that is a rewrite of an application, originally written in Foxpro 2.6 by someone before me, that performs some analysis (which, sadly, I'm not allowed to disclose as per of my employment contract) on financial data. One day, after a long talk between the client and I -- where he intimately described his frustrations with all the bugs I've been hacking out of this code for 6 months now -- he told me to just rewrite it and gave me a month to write a good 1/8 of this 65k LOC Foxpro monstrosity. this 65k line of code foxpro monstrosity. It'll take me a good 3 - 6 months to rewrite this software (I know things the original programmer did not, like inheritance) going as I am right now, but I'm quickly discovering that I'm going to need to use databases. Prior to this contract I didn't even know about foxpro, and so I've had to learn foxpro on the fly, write procedures and make modifications to the database. I've actually come to like it, and this project would be rewritten in Foxpro if it were still a supported language, because over the past few months, I've come to like the features of Foxpro that make it so easy to develop data-driven applications. I once perfomed an experiment, comparing C# to Foxpro. What took me 45 minutes in C# took me two in Foxpro, and I knew C# prior to Foxpro. I was hoping to leverage the power of C#, but it intimidates me that in foxpro, you can have one line of code and be using a database. Prior to this, I have never written any serious database development from scratch. All the applications that I've written are in a different league. They are either completely data-naive or data-naive enough that I can get away with not using a database through serialization or by designing algorithms that work with the data in a manner that is stateless, so there is no need to worry about databases. I've come to realize, very quickly, that serialization and my efficacy with data structures has been my crutch all these years that's prevented me from adventuring into databases, and has consequently hindered my success in real-world programming. Sure, I've written some database stuff in Perl and Python, and I've done forms and worked with relational databases and tables, I'm a wizard in Access and Excel (seriously) and can do just about anything, but it just feels unnatural writing SQL code in another language... I don't mind writing SQL, and I don't It's that bridge between the database and the program code that drives me absolutely bonkers. I hope I'm not the only one to think this, but it bothers me that I have to create statements like the following string sSql = "SELECT * from tablename" When there's really no reason for that kind of unchecked language binding between two languages and two API's. Don't get my wrong, SQL is great, but I don't like the idea that, when executing commands on a SQL database, that one must intermix database and application software, and there's no database independence, which means that different versions of different databases can break code. This isn't very nice. The nicest thing about Foxpro is the cohesiveness between programming language and database. It's so easy, and Foxpro makes it easy, because the tool just fits the task. I can see why so many developers have created a career with this language, because it lowered the barrier of entry to data-driven applications that so many businesses need. It was wonderful. For my purposes today, with the demands and need for community support, extensibility, and language features, Foxpro isn't a solution that I feel would be the right tool for the job. I'm also worried about working too heavy with the database, because I've seen data-driven .NET applications have issues with database caches, running out of memory, and objects in the database not being collected. (Memory leaks) And OH the queries. Which one, how, and why? There are a plethora of different ways that a database can be setup, I think I counted 5 or 6 different kinds of database applications alone that I can chose from. That is a great mountain for me to climb when I don't even know where to begin when it comes to writing data-driven applications. The problem isn't that I don't know SQL or that I don't know C#. I know both and have worked with both extensively. It's making them work together that's the problem, and it's something I've never done in C# before. Reports The client likes paper. The data needs to be printed out in a format that is extensible, layered, and easy to use. I have never done reporting before, and so this is a bit of a problem. From the data source comes crystal reports, and so there's a dependency on the database, from what I understand. Code reuse A large part of the design decision that I've gone through so far is to break the task of writing a piece of this software into routines and modular DLL's and so forth such that much of the code can be reused. For example, when I setup this database, I want to be able to reuse the same database code over and over again. I also want to make sure that when the day comes that another developer is here, that he/she will be able to pick up just where I left off. The quicker I develop these applications, the better off I am. Tasks & Goals In my project, I need to write routines that apply algorithms and look for predefined patterns in financial data. Additionally, I need to simulate trading based on predefined algorithms and data. Then I need to prepare reports on that data. Additionally, I need to have a way to change the code base for this application quickly and effectively, without hacking together some band-aid solution for a problem that really needs a trauma ward. Special Considerations The solution must be fast, run quickly on existing hardware, and not be too much of a pain to maintain and write. I understand that anything I write I'm married to -- I'm responsible for the things that I write because my reputation and livelihood is dependent on it. Do I really need a database? What about performance? Performance was such a big issue that I hand wrote a data structure that is capable of performing 2 billion operations, using a total of 4 gigs of memory in under 1/4 of a second using the standard core two duo processor. I could not find a similar, pre-written data structure in C# to perform this task. What setup do I use in terms of database? What about reporting? I'd prefer to have PDF's generated, but I'd like to be able to visually sketch those reports and then just have a ReportFactory of some sort, that when I pass some variables in, it just does that data. About Me I'm a lone developer for a small business in this area. This is the first time I've done this and I've never had the breadth and depth of my knowledge tested. I'm incredibly frustrated with this project because I feel incredibly overwhelmed with the task at hand. I'm looking for that entry level point where I can draw a line and say "this is what I need to do" Conclusion I may have not been clear enough on my post. I'm still new to this whole thing, and I've been doing my best to contribute back to the community that I've leached so much knowledge from. I'd be glad to edit my post and add more information if possible. I'm looking for a big-picture solution or design process that helps me get off the ground in this world of data-driven applications, because I have a feeling that it's going to be concentric to my entire career as a programmer for some time. Specifically, if you didn't get it from the rest of the post (I may not have been clear enough) I really need some guidance as to where to go in terms of the design decisions for this project. Some things that'll be useful will be a pro/con list for the different kinds of database projects available in VS2010. I've tried, but generating that list has been as hard as solving the problem itself... If you could walk a developer writing a data-driven application for the first time in C#, how would you do that? Where would you point them to?

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• ASP.NET MVC Postbacks and HtmlHelper Controls ignoring Model Changes

  - by Rick Strahl

  So here's a binding behavior in ASP.NET MVC that I didn't really get until today: HtmlHelpers controls (like .TextBoxFor() etc.) don't bind to model values on Postback, but rather get their value directly out of the POST buffer from ModelState. Effectively it looks like you can't change the display value of a control via model value updates on a Postback operation. To demonstrate here's an example. I have a small section in a document where I display an editable email address: This is what the form displays on a GET operation and as expected I get the email value displayed in both the textbox and plain value display below, which reflects the value in the mode. I added a plain text value to demonstrate the model value compared to what's rendered in the textbox. The relevant markup is the email address which needs to be manipulated via the model in the Controller code. Here's the Razor markup: <div class="fieldcontainer"> <label> Email: &nbsp; <small>(username and <a href="http://gravatar.com">Gravatar</a> image)</small> </label> <div> @Html.TextBoxFor( mod=> mod.User.Email, new {type="email",@class="inputfield"}) @Model.User.Email </div> </div>   So, I have this form and the user can change their email address. On postback the Post controller code then asks the business layer whether the change is allowed. If it's not I want to reset the email address back to the old value which exists in the database and was previously store. The obvious thing to do would be to modify the model. Here's the Controller logic block that deals with that:// did user change email? if (!string.IsNullOrEmpty(oldEmail) && user.Email != oldEmail) { if (userBus.DoesEmailExist(user.Email)) { userBus.ValidationErrors.Add("New email address exists already. Please…"); user.Email = oldEmail; } else // allow email change but require verification by forcing a login user.IsVerified = false; }… model.user = user; return View(model); The logic is straight forward - if the new email address is not valid because it already exists I don't want to display the new email address the user entered, but rather the old one. To do this I change the value on the model which effectively does this:model.user.Email = oldEmail; return View(model); So when I press the Save button after entering in my new email address ([email protected]) here's what comes back in the rendered view: Notice that the textbox value and the raw displayed model value are different. The TextBox displays the POST value, the raw value displays the actual model value which are different. This means that MVC renders the textbox value from the POST data rather than from the view data when an Http POST is active. Now I don't know about you but this is not the behavior I expected - initially. This behavior effectively means that I cannot modify the contents of the textbox from the Controller code if using HtmlHelpers for binding. Updating the model for display purposes in a POST has in effect - no effect. (Apr. 25, 2012 - edited the post heavily based on comments and more experimentation) What should the behavior be? After getting quite a few comments on this post I quickly realized that the behavior I described above is actually the behavior you'd want in 99% of the binding scenarios. You do want to get the POST values back into your input controls at all times, so that the data displayed on a form for the user matches what they typed. So if an error occurs, the error doesn't mysteriously disappear getting replaced either with a default value or some value that you changed on the model on your own. Makes sense. Still it is a little non-obvious because the way you create the UI elements with MVC, it certainly looks like your are binding to the model value:@Html.TextBoxFor( mod=> mod.User.Email, new {type="email",@class="inputfield",required="required" }) and so unless one understands a little bit about how the model binder works this is easy to trip up. At least it was for me. Even though I'm telling the control which model value to bind to, that model value is only used initially on GET operations. After that ModelState/POST values provide the display value. Workarounds The default behavior should be fine for 99% of binding scenarios. But if you do need fix up values based on your model rather than the default POST values, there are a number of ways that you can work around this. Initially when I ran into this, I couldn't figure out how to set the value using code and so the simplest solution to me was simply to not use the MVC Html Helper for the specific control and explicitly bind the model via HTML markup and @Razor expression: <input type="text" name="User.Email" id="User_Email" value="@Model.User.Email" /> And this produces the right result. This is easy enough to create, but feels a little out of place when using the @Html helpers for everything else. As you can see by the difference in the name and id values, you also are forced to remember the naming conventions that MVC imposes in order for ModelBinding to work properly which is a pain to remember and set manually (name is the same as the property with . syntax, id replaces dots with underlines). Use the ModelState Some of my original confusion came because I didn't understand how the model binder works. The model binder basically maintains ModelState on a postback, which holds a value and binding errors for each of the Post back value submitted on the page that can be mapped to the model. In other words there's one ModelState entry for each bound property of the model. Each ModelState entry contains a value property that holds AttemptedValue and RawValue properties. The AttemptedValue is essentially the POST value retrieved from the form. The RawValue is the value that the model holds. When MVC binds controls like @Html.TextBoxFor() or @Html.TextBox(), it always binds values on a GET operation. On a POST operation however, it'll always used the AttemptedValue to display the control. MVC binds using the ModelState on a POST operation, not the model's value. So, if you want the behavior that I was expecting originally you can actually get it by clearing the ModelState in the controller code:ModelState.Clear(); This clears out all the captured ModelState values, and effectively binds to the model. Note this will produce very similar results - in fact if there are no binding errors you see exactly the same behavior as if binding from ModelState, because the model has been updated from the ModelState already and binding to the updated values most likely produces the same values you would get with POST back values. The big difference though is that any values that couldn't bind - like say putting a string into a numeric field - will now not display back the value the user typed, but the default field value or whatever you changed the model value to. This is the behavior I was actually expecting previously. But - clearing out all values might be a bit heavy handed. You might want to fix up one or two values in a model but rarely would you want the entire model to update from the model. So, you can also clear out individual values on an as needed basis:if (userBus.DoesEmailExist(user.Email)) { userBus.ValidationErrors.Add("New email address exists already. Please…"); user.Email = oldEmail; ModelState.Remove("User.Email"); } This allows you to remove a single value from the ModelState and effectively allows you to replace that value for display from the model. Why? While researching this I came across a post from Microsoft's Brad Wilson who describes the default binding behavior best in a forum post: The reason we use the posted value for editors rather than the model value is that the model may not be able to contain the value that the user typed. Imagine in your "int" editor the user had typed "dog". You want to display an error message which says "dog is not valid", and leave "dog" in the editor field. However, your model is an int: there's no way it can store "dog". So we keep the old value. If you don't want the old values in the editor, clear out the Model State. That's where the old value is stored and pulled from the HTML helpers. There you have it. It's not the most intuitive behavior, but in hindsight this behavior does make some sense even if at first glance it looks like you should be able to update values from the model. The solution of clearing ModelState works and is a reasonable one but you have to know about some of the innards of ModelState and how it actually works to figure that out.© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Advantages of SQL Backup Pro

  - by Grant Fritchey

  Getting backups of your databases in place is a fundamental issue for protection of the business. Yes, I said business, not data, not databases, but business. Because of a lack of good, tested, backups, companies have gone completely out of business or suffered traumatic financial loss. That’s just a simple fact (outlined with a few examples here). So you want to get backups right. That’s a big part of why we make Red Gate SQL Backup Pro work the way it does. Yes, you could just use native backups, but you’ll be missing a few advantages that we provide over and above what you get out of the box from Microsoft. Let’s talk about them. Guidance If you’re a hard-core DBA with 20+ years of experience on every version of SQL Server and several other data platforms besides, you may already know what you need in order to get a set of tested backups in place. But, if you’re not, maybe a little help would be a good thing. To set up backups for your servers, we supply a wizard that will step you through the entire process. It will also act to guide you down good paths. For example, if your databases are in Full Recovery, you should set up transaction log backups to run on a regular basis. When you choose a transaction log backup from the Backup Type you’ll see that only those databases that are in Full Recovery will be listed: This makes it very easy to be sure you have a log backup set up for all the databases you should and none of the databases where you won’t be able to. There are other examples of guidance throughout the product. If you have the responsibility of managing backups but very little knowledge or time, we can help you out. Throughout the software you’ll notice little green question marks. You can see two in the screen above and more in each of the screens in other topics below this one. Clicking on these will open a window with additional information about the topic in question which should help to guide you through some of the tougher decisions you may have to make while setting up your backup jobs. Here’s an example: Backup Copies As a part of the wizard you can choose to make a copy of your backup on your network. This process runs as part of the Red Gate SQL Backup engine. It will copy your backup, after completing the backup so it doesn’t cause any additional blocking or resource use within the backup process, to the network location you define. Creating a copy acts as a mechanism of protection for your backups. You can then backup that copy or do other things with it, all without affecting the original backup file. This requires either an additional backup or additional scripting to get it done within the native Microsoft backup engine. Offsite Storage Red Gate offers you the ability to immediately copy your backup to the cloud as a further, off-site, protection of your backups. It’s a service we provide and expose through the Backup wizard. Your backup will complete first, just like with the network backup copy, then an asynchronous process will copy that backup to cloud storage. Again, this is built right into the wizard or even the command line calls to SQL Backup, so it’s part a single process within your system. With native backup you would need to write additional scripts, possibly outside of T-SQL, to make this happen. Before you can use this with your backups you’ll need to do a little setup, but it’s built right into the product to get this done. You’ll be directed to the web site for our hosted storage where you can set up an account. Compression If you have SQL Server 2008 Enterprise, or you’re on SQL Server 2008R2 or greater and you have a Standard or Enterprise license, then you have backup compression. It’s built right in and works well. But, if you need even more compression then you might want to consider Red Gate SQL Backup Pro. We offer four levels of compression within the product. This means you can get a little compression faster, or you can just sacrifice some CPU time and get even more compression. You decide. For just a simple example I backed up AdventureWorks2012 using both methods of compression. The resulting file from native was 53mb. Our file was 33mb. That’s a file that is smaller by 38%, not a small number when we start talking gigabytes. We even provide guidance here to help you determine which level of compression would be right for you and your system: So for this test, if you wanted maximum compression with minimum CPU use you’d probably want to go with Level 2 which gets you almost as much compression as Level 3 but will use fewer resources. And that compression is still better than the native one by 10%. Restore Testing Backups are vital. But, a backup is just a file until you restore it. How do you know that you can restore that backup? Of course, you’ll use CHECKSUM to validate that what was read from disk during the backup process is what gets written to the backup file. You’ll also use VERIFYONLY to check that the backup header and the checksums on the backup file are valid. But, this doesn’t do a complete test of the backup. The only complete test is a restore. So, what you really need is a process that tests your backups. This is something you’ll have to schedule separately from your backups, but we provide a couple of mechanisms to help you out here. First, when you create a backup schedule, all done through our wizard which gives you as much guidance as you get when running backups, you get the option of creating a reminder to create a job to test your restores. You can enable this or disable it as you choose when creating your scheduled backups. Once you’re ready to schedule test restores for your databases, we have a wizard for this as well. After you choose the databases and restores you want to test, all configurable for automation, you get to decide if you’re going to restore to a specified copy or to the original database: If you’re doing your tests on a new server (probably the best choice) you can just overwrite the original database if it’s there. If not, you may want to create a new database each time you test your restores. Another part of validating your backups is ensuring that they can pass consistency checks. So we have DBCC built right into the process. You can even decide how you want DBCC run, which error messages to include, limit or add to the checks being run. With this you could offload some DBCC checks from your production system so that you only run the physical checks on your production box, but run the full check on this backup. That makes backup testing not just a general safety process, but a performance enhancer as well: Finally, assuming the tests pass, you can delete the database, leave it in place, or delete it regardless of the tests passing. All this is automated and scheduled through the SQL Agent job on your servers. Running your databases through this process will ensure that you don’t just have backups, but that you have tested backups. Single Point of Management If you have more than one server to maintain, getting backups setup could be a tedious process. But, with Red Gate SQL Backup Pro you can connect to multiple servers and then manage all your databases and all your servers backups from a single location. You’ll be able to see what is scheduled, what has run successfully and what has failed, all from a single interface without having to connect to different servers. Log Shipping Wizard If you want to set up log shipping as part of a disaster recovery process, it can frequently be a pain to get configured correctly. We supply a wizard that will walk you through every step of the process including setting up alerts so you’ll know should your log shipping fail. Summary You want to get your backups right. As outlined above, Red Gate SQL Backup Pro will absolutely help you there. We supply a number of processes and functionalities above and beyond what you get with SQL Server native. Plus, with our guidance, hints and reminders, you will get your backups set up in a way that protects your business.

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• Eclipse buildtime and runtime classpaths for easy execution of junit test cases

  - by emeraldjava

  Hey, I've a large eclipse project with multiple junit classes. I'm trying to strike a balance between adding runtime resources to the eclipse project classpath, and the need to configure mutliple junit launch configurations. I realise the default eclipse build classpath is inherited by all unit test configurations, but some of my tests require extra runtime resources. I could add these resources to the build classpath, but this does slow my overall project build time (since it has to keep more files in synch). I don't like the idea of including * resources and jars on the runtime classpath. The two options that i have are these, the positive and negative cases as i see it are listed 1 : Add all runtime resources to eclipse classpath. POS I can select a unit test and run it without having to configure the test classpath. POS Extra resources on build classpath means eclipse slows down. NEG More difficult to ensure each test uses the correct resources. 2 : Configure the classpath of each unit test POS I know exactly what resources are being used by a test. POS Smaller build classpath means quicker build and execution by eclipse. NEG Its a pain having to setup multiple separate junit runtime classpaths. Ideally i'd like to configure one base junit runtime configuration, which takes the default eclipse build classpath, adds extra runtime jars and resources. This configuration could then be reused by the specific junit test cases, Is anything like this possible? Looking at a specific junit launch configuration which can be exported to a share project file <?xml version="1.0" encoding="UTF-8" standalone="no"?> <launchConfiguration type="org.eclipse.jdt.junit.launchconfig"> <stringAttribute key="bad_container_name" value="/CR-3089_5_1_branch."/> <listAttribute key="org.eclipse.debug.core.MAPPED_RESOURCE_PATHS"> <listEntry value="/CR-3089_5_1_branch/src/com/x/y/z/ParserJUnitTest.java"/> </listAttribute> <listAttribute key="org.eclipse.debug.core.MAPPED_RESOURCE_TYPES"> <listEntry value="1"/> </listAttribute> <stringAttribute key="org.eclipse.jdt.junit.CONTAINER" value=""/> <booleanAttribute key="org.eclipse.jdt.junit.KEEPRUNNING_ATTR" value="false"/> <stringAttribute key="org.eclipse.jdt.junit.TESTNAME" value=""/> <stringAttribute key="org.eclipse.jdt.junit.TEST_KIND" value="org.eclipse.jdt.junit.loader.junit4"/> <stringAttribute key="org.eclipse.jdt.launching.MAIN_TYPE" value="com.x.y.z.ParserJUnitTest"/> <stringAttribute key="org.eclipse.jdt.launching.PROJECT_ATTR" value="CR-3089_5_1_branch"/> </launchConfiguration> is it possible to extend/reuse this configuration, and parameterise the 'org.eclipse.jdt.launching.MAIN_TYPE' value? I'm aware of the commons launch and jar manifest file solutions to configuring the classpath, but they both seem to assume that an ant build is run before the test can execute. I want to avoid any eclipse dependency on calling an ant target when refactoting code and executing tests. Basically - What is the the easiest way to seperate and maintain the eclipse buildtime classpath and junit runtime classpaths?

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• Installing a configuration profile on iPhone - programmatically

  - by Seva Alekseyev

  Hi all, I would like to ship a configuration profile with my iPhone application, and install it if needed. Mind you, we're talking about a configuration profile, not a provisioning profile. First off, such a task is possible. If you place a config profile on a Web page and click on it from Safari, it will get installed. If you e-mail a profile and click the attachment, it will install as well. "Installed" in this case means "The installation UI is invoked" - but I could not even get that far. So I was working under the theory that initiating a profile installation involves navigating to it as a URL. I added the profile to my app bundle. A) First, I tried [sharedApp openURL] with the file:// URL into my bundle. No such luck - nothing happens. B) I then added an HTML page to my bundle that has a link to the profile, and loaded it into a UIWebView. Clicking on the link does nothing. Loading an identical page from a Web server in Safari, however, works fine - the link is clickable, the profile installs. I provided a UIWebViewDelegate, answering YES to every navigation request - no difference. C) Then I tried to load the same Web page from my bundle in Safari (using [sharedApp openURL] - nothing happens. I guess, Safari cannot see files inside my app bundle. D) Uploading the page and the profile on a Web server is doable, but a pain on the organizational level, not to mention an extra source of failures (what if no 3G coverage? etc.). So my big question is: how do I install a profile programmatically? And the little questions are: what can make a link non-clickable within a UIWebView? Is it possible to load a file:// URL from my bundle in Safari? If not, is there a local location on iPhone where I can place files and Safari can find them? EDIT on B): the problem is somehow in the fact that we're linking to a profile. I renamed it from .mobileconfig to .xml ('cause it's really XML), altered the link. And the link worked in my UIWebView. Renamed it back - same stuff. It looks as if UIWebView is reluctant to do application-wide stuff - since installation of the profile closes the app. I tried telling it that it's OK - by means of UIWebViewDelegate - but that did not convince. Same behavior for mailto: URLs within UIWebView. For mailto: URLs the common technique is to translate them into [openURL] calls, but that doesn't quite work for my case, see scenario A. For itms: URLs, however, UIWebView works as expected... EDIT2: tried feeding a data URL to Safari via [openURL] - does not work, see here: http://stackoverflow.com/questions/641461/iphone-open-data-url-in-safari EDIT3: found a lot of info on how Safari does not support file:// URLs. UIWebView, however, very much does. Also, Safari on the simulator open them just fine. The latter bit is the most frustrating.

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• PASS Summit Feedback

  - by Rob Farley

  PASS Feedback came in last week. I also saw my dentist for some fillings... At the PASS Summit this year, I delivered a couple of regular sessions and a Lightning Talk. People told me they enjoyed it, but when the rankings came out, they showed that I didn’t score particularly well. Brent Ozar was keen to discuss it with me. Brent: PASS speaker feedback is out. You did two sessions and a Lightning Talk. How did you go? Rob: Not so well actually, thanks for asking. Brent: Ha! Sorry. Of course you know that's why I wanted to discuss this with you. I was in one of your sessions at SQLBits in the UK a month before PASS, and I thought you rocked. You've got a really good and distinctive delivery style.  Then I noticed your talks were ranked in the bottom quarter of the Summit ratings and wanted to discuss it. Rob: Yeah, I know. You did ask me if we could do this...  I should explain – my presentation style is not the stereotypical IT conference one. I throw in jokes, and try to engage the audience thoroughly. I find many talks amazingly dry, and I guess I try to buck that trend. I also run training courses, and find that I get a lot of feedback from people thanking me for keeping things interesting. That said, I also get feedback criticising me for my style, and that’s basically what’s happened here. For the rest of this discussion, let’s focus on my talk about the Incredible Shrinking Execution Plan, which I considered to be my main talk. Brent: I thought that session title was the very best one at the entire Summit, and I had it on my recommended sessions list.  In four words, you managed to sum up the topic and your sense of humor.  I read that and immediately thought, "People need to be in this session," and then it didn't score well.  Tell me about your scores. Rob: The questions on the feedback form covered the usefulness of the information, the speaker’s presentation skills, their knowledge of the subject, how well the session was described, the amount of time allocated, and the quality of the presentation materials. Brent: Presentation materials? But you don’t do slides.  Did they rate your thong? Rob: No-one saw my flip-flops in this talk, Brent. I created a script in Management Studio, and published that afterwards, but I think people will have scored that question based on the lack of slides. I wasn’t expecting to do particularly well on that one. That was the only section that didn’t have 5/5 as the most popular score. Brent: See, that sucks, because cookbook-style scripts are often some of my favorites.  Adam Machanic's Service Broker workbench series helped me immensely when I was prepping for the MCM.  As an attendee, I'd rather have a commented script than a slide deck.  So how did you rank so low? Rob: When I look at the scores that you got (based on your blog post), you got very few scores below 3 – people that felt strong enough about your talk to post a negative score. In my scores, between 5% and 10% were below 3 (except on the question about whether I knew my stuff – I guess I came as knowledgeable). Brent: Wow – so quite a few people really didn’t like your talk then? Rob: Yeah. Mind you, based on the comments, some people really loved it. I’d like to think that there would be a certain portion of the room who may have rated the talk as one of the best of the conference. Some of my comments included “amazing!”, “Best presentation so far!”, “Wow, best session yet”, “fantastic” and “Outstanding!”. I think lots of talks can be “Great”, but not so many talks can be “Outstanding” without the word losing its meaning. One wrote “Pretty amazing presentation, considering it was completely extemporaneous.” Brent: Extemporaneous, eh? Rob: Yeah. I guess they don’t realise how much preparation goes into coming across as unprepared. In many ways it’s much easier to give a written speech than to deliver a presentation without slides as a prompt. Brent: That delivery style, the really relaxed, casual, college-professor approach was one of the things I really liked about your presentation at SQLbits.  As somebody who presents a lot, I "get" it - I know how hard it is to come off as relaxed and comfortable with your own material.  It's like improv done by jazz players and comedians - if you've never tried it, you don't realize how hard it is.  People also don't realize how hard it is to make a tough subject fun. Rob: Yeah well... There will be people writing comments on this post that say I wasn't trying to make the subject fun, and that I was making it all about me. Sometimes the style works, sometimes it doesn't. Most of the comments mentioned the fact that I tell jokes, some in a nice way, but some not so much (and it wasn't just a PASS thing - that's the mix of feedback I generally get). One comment at PASS was: “great stand up comedian - not what I'm looking for at pass”, and there were certainly a few that said “too many jokes”. I’m not trying to do stand-up – jokes are my way of engaging with the audience while I demonstrate some of the amazing things that the Query Optimizer can do if you write your queries the right way. Some people didn’t think it was technical enough, but I’ve also had some people tell me that the concepts I’m explaining are deep and profound. Brent: To me, that's a hallmark of a great explanation - when someone says, "But of course it has to work that way - how could it work any other way?  It seems so simple and logical."  Well, sure it does when it's explained correctly, but now pick up any number of thick SQL Server books and try to understand the Redundant Joins concept.  I guarantee it'll take more than 45 minutes. Rob: Some people in my audiences realise that, but definitely not everyone. There's only so much you can tell someone that something is profound. Generally it's something that they either have an epiphany on or not. I like to lull my audience into knowing what's going on, and do something that surprises them. Gain their trust, build a rapport, and then show them the deeper truth of what just happened. Brent: So you've learned your lesson about presentation scores, right?  From here on out, you're going to be dry, humorless, and all your presentations will consist of you reading bullet points off the screen. Rob: No Brent, I’m not. I'm also not going to suggest that most presentations at PASS are like that. No-one tries to present like that. There's a big space to occupy between what "dry and humourless" and me. My difference is to focus on the relationship I have with the crowd, rather than focussing on delivering the perfect session. I want to see people smiling and know they're relaxed. I think most presenters focus on the material, which is completely reasonable and safe. I remember once hearing someone talking about product creation. They talked about mediocrity. They said that one of the worst things that people can ever say about your product is that it’s “good”. What you want is for 10% of the world to love it enough to want to buy it. If 10% the world gave me a dollar, I’d have more money than I could ever use (assuming it wasn’t the SAME dollar they were giving me I guess). Brent: It's the Raving Fans theory.  It's better to have a small number of raving customers than a large number of almost-but-not-really customers who don't care that much about your product or service.  I know exactly how you feel - when I got survey feedback from my Quest video presentation when I was dressed up in a Richard Simmons costume, some of the attendees said I was unprofessional and distracting.  Some of the attendees couldn't get enough and Photoshopped all kinds of stuff into the screen captures.  On a whole, I probably didn't score that well, and I'm fine with that.  It sucks to look at the scores though - do those lower scores bother you? Rob: Of course they do. It hurts deeply. I open myself up and give presentations in a very personal way. All presenters do that, and we all feel the pain of negative feedback. I hate coming 146th & 162nd out of 185, but have to acknowledge that many sessions did worse still. Plus, once I feel the wounds have healed, I’ll be able to remember that there are people in the world that rave about my presentation style, and figure that people will hopefully talk about me. One day maybe those people that don’t like my presentation style will stay away and I might be able to score better. You don’t pay to hear country music if you prefer western... Lots of people find chili too spicy, but it’s still a popular food. Brent: But don’t you want to appeal to everyone? Rob: I do, but I don’t want to be lukewarm as in Revelation 3:16. I’d rather disgust and be discussed. Well, maybe not ‘disgust’, but I don’t want to conform. Conformity just isn’t the same any more. I’m not sure I’ve ever been one to do that. I try not to offend, but definitely like to be different. Brent: Count me among your raving fans, sir.  Where can we see you next? Rob: Considering I live in Adelaide in Australia, I’m not about to appear at anyone’s local SQL Saturday. I’m still trying to plan which events I’ll get to in 2011. I’ve submitted abstracts for TechEd North America, but won’t hold my breath. I’m also considering the SQLBits conferences in the UK in April, PASS in October, and I’m sure I’ll do some LiveMeeting presentations for user groups. Online, people download some of my recent SQLBits presentations at http://bit.ly/RFSarg and http://bit.ly/Simplification though. And they can download a 5-minute MP3 of my Lightning Talk at http://www.lobsterpot.com.au/files/Collation.mp3, in which I try to explain the idea behind collation, using thongs as an example. Brent: I was in the audience for http://bit.ly/RFSarg. That was a great presentation. Rob: Thanks, Brent. Now where’s my dollar?

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• Simple animation using C#/Windows Forms

  - by clintp

  I need to knock out a quick animation in C#/Windows Forms for a Halloween display. Just some 2D shapes moving about on a solid background. Since this is just a quick one-off project I really don't want to install and learn an entire new set of tools for this. (DirectX dev kits, Silverlight, Flash, etc..) I also have to install this on multiple computers so anything beyond the basic .Net framework (2.0) would be a pain in the arse. For tools I've got VS2k8, 25 years of development experience, a wheelbarrow, holocaust cloak, and about 2 days to knock this out. I haven't done animation since using assembler on my Atari 130XE (hooray for page flipping and player/missile graphics!) Advice? Here's some of the things I'd like to know: I can draw on any empty widget (like a panel) by fiddling with it's OnPaint handler, right? That's how I'd draw a custom widget. Is there a better technique than this? Is there a page-flipping technique for this kind of thing in Windows Forms? I'm not looking for a high frame rate, just as little flicker/drawing as necessary. Thanks. Post Mortem Edit ... "a couple of coding days later" Well, the project is done. The links below came in handy although a couple of them were 404. (I wish SO would allow more than one reply to be marked "correct"). The biggest problem I had to overcome was flickering, and a persistent bug when I tried to draw on the form directly. Using the OnPaint event for the Form: bad idea. I never got that to work; lots of mysterious errors (stack overflows, or ArgumentNullExceptions). I wound up using a panel sized to fill the form and that worked fine. Using the OnPaint method is slow anyway. Somewhere online I read that building the PaintEventArgs was slow, and they weren't kidding. Lots of flickering went away when I abandoned this. Skip the OnPaint/Invalidate() and just paint it yourself. Setting all of the "double buffering" options on the form still left some flicker that had to be fixed. (And I found conflicting docs that said "set them on the control" and "set them on the form". Well controls don't have a .SetStyle() method.) I haven't tested without them, so they might be doing something (this is the form): this.SetStyle(ControlStyles.UserPaint, true); this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true); this.SetStyle(ControlStyles.AllPaintingInWmPaint, true); So the workhorse of the code wound up looking like (pf is the panel control): void PaintPlayField() { Bitmap bufl = new Bitmap(pf.Width, pf.Height); using (Graphics g = Graphics.FromImage(bufl)) { g.FillRectangle(Brushes.Black, new Rectangle(0, 0, pf.Width, pf.Height)); DrawItems(g); DrawMoreItems(g); pf.CreateGraphics().DrawImageUnscaled(bufl, 0, 0); } } And I just called PaintPlayField from the inside of my Timer loop. No flicker at all.

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• MVC Automatic Menu

  - by Nuri Halperin

  An ex-colleague of mine used to call his SQL script generator "Super-Scriptmatic 2000". It impressed our then boss little, but was fun to say and use. We called every batch job and script "something 2000" from that day on. I'm tempted to call this one Menu-Matic 2000, except it's waaaay past 2000. Oh well. The problem: I'm developing a bunch of stuff in MVC. There's no PM to generate mounds of requirements and there's no Ux Architect to create wireframe. During development, things change. Specifically, actions get renamed, moved from controller x to y etc. Well, as the site grows, it becomes a major pain to keep a static menu up to date, because the links change. The HtmlHelper doesn't live up to it's name and provides little help. How do I keep this growing list of pesky little forgotten actions reigned in? The general plan is: Decorate every action you want as a menu item with a custom attribute Reflect out all menu items into a structure at load time Render the menu using as CSS  friendly <ul><li> HTML. The MvcMenuItemAttribute decorates an action, designating it to be included as a menu item: [AttributeUsage(AttributeTargets.Method, AllowMultiple = true)] public class MvcMenuItemAttribute : Attribute {   public string MenuText { get; set; }   public int Order { get; set; }   public string ParentLink { get; set; }   internal string Controller { get; set; }   internal string Action { get; set; }     #region ctor   public MvcMenuItemAttribute(string menuText) : this(menuText, 0) { } public MvcMenuItemAttribute(string menuText, int order) { MenuText = menuText; Order = order; }       internal string Link { get { return string.Format("/{0}/{1}", Controller, this.Action); } }   internal MvcMenuItemAttribute ParentItem { get; set; } #endregion } The MenuText allows overriding the text displayed on the menu. The Order allows the items to be ordered. The ParentLink allows you to make this item a child of another menu item. An example action could then be decorated thusly: [MvcMenuItem("Tracks", Order = 20, ParentLink = "/Session/Index")] . All pretty straightforward methinks. The challenge with menu hierarchy becomes fairly apparent when you try to render a menu and highlight the "current" item or render a breadcrumb control. Both encounter an  ambiguity if you allow a data source to have more than one menu item with the same URL link. The issue is that there is no great way to tell which link a person click. Using referring URL will fail if a user bookmarked the page. Using some extra query string to disambiguate duplicate URLs essentially changes the links, and also ads a chance of collision with other query parameters. Besides, that smells. The stock ASP.Net sitemap provider simply disallows duplicate URLS. I decided not to, and simply pick the first one encountered as the "current". Although it doesn't solve the issue completely – one might say they wanted the second of the 2 links to be "current"- it allows one to include a link twice (home->deals and products->deals etc), and the logic of deciding "current" is easy enough to explain to the customer. Now that we got that out of the way, let's build the menu data structure: public static List<MvcMenuItemAttribute> ListMenuItems(Assembly assembly) { var result = new List<MvcMenuItemAttribute>(); foreach (var type in assembly.GetTypes()) { if (!type.IsSubclassOf(typeof(Controller))) { continue; } foreach (var method in type.GetMethods()) { var items = method.GetCustomAttributes(typeof(MvcMenuItemAttribute), false) as MvcMenuItemAttribute[]; if (items == null) { continue; } foreach (var item in items) { if (String.IsNullOrEmpty(item.Controller)) { item.Controller = type.Name.Substring(0, type.Name.Length - "Controller".Length); } if (String.IsNullOrEmpty(item.Action)) { item.Action = method.Name; } result.Add(item); } } } return result.OrderBy(i => i.Order).ToList(); } Using reflection, the ListMenuItems method takes an assembly (you will hand it your MVC web assembly) and generates a list of menu items. It digs up all the types, and for each one that is an MVC Controller, digs up the methods. Methods decorated with the MvcMenuItemAttribute get plucked and added to the output list. Again, pretty simple. To make the structure hierarchical, a LINQ expression matches up all the items to their parent: public static void RegisterMenuItems(List<MvcMenuItemAttribute> items) { _MenuItems = items; _MenuItems.ForEach(i => i.ParentItem = items.FirstOrDefault(p => String.Equals(p.Link, i.ParentLink, StringComparison.InvariantCultureIgnoreCase))); } The _MenuItems is simply an internal list to keep things around for later rendering. Finally, to package the menu building for easy consumption: public static void RegisterMenuItems(Type mvcApplicationType) { RegisterMenuItems(ListMenuItems(Assembly.GetAssembly(mvcApplicationType))); } To bring this puppy home, a call in Global.asax.cs Application_Start() registers the menu. Notice the ugliness of reflection is tucked away from the innocent developer. All they have to do is call the RegisterMenuItems() and pass in the type of the application. When you use the new project template, global.asax declares a class public class MvcApplication : HttpApplication and that is why the Register call passes in that type. protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes);   MvcMenu.RegisterMenuItems(typeof(MvcApplication)); }   What else is left to do? Oh, right, render! public static void ShowMenu(this TextWriter output) { var writer = new HtmlTextWriter(output);   renderHierarchy(writer, _MenuItems, null); }   public static void ShowBreadCrumb(this TextWriter output, Uri currentUri) { var writer = new HtmlTextWriter(output); string currentLink = "/" + currentUri.GetComponents(UriComponents.Path, UriFormat.Unescaped);   var menuItem = _MenuItems.FirstOrDefault(m => m.Link.Equals(currentLink, StringComparison.CurrentCultureIgnoreCase)); if (menuItem != null) { renderBreadCrumb(writer, _MenuItems, menuItem); } }   private static void renderBreadCrumb(HtmlTextWriter writer, List<MvcMenuItemAttribute> menuItems, MvcMenuItemAttribute current) { if (current == null) { return; } var parent = current.ParentItem; renderBreadCrumb(writer, menuItems, parent); writer.Write(current.MenuText); writer.Write(" / ");   }     static void renderHierarchy(HtmlTextWriter writer, List<MvcMenuItemAttribute> hierarchy, MvcMenuItemAttribute root) { if (!hierarchy.Any(i => i.ParentItem == root)) return;   writer.RenderBeginTag(HtmlTextWriterTag.Ul); foreach (var current in hierarchy.Where(element => element.ParentItem == root).OrderBy(i => i.Order)) { if (ItemFilter == null || ItemFilter(current)) {   writer.RenderBeginTag(HtmlTextWriterTag.Li); writer.AddAttribute(HtmlTextWriterAttribute.Href, current.Link); writer.AddAttribute(HtmlTextWriterAttribute.Alt, current.MenuText); writer.RenderBeginTag(HtmlTextWriterTag.A); writer.WriteEncodedText(current.MenuText); writer.RenderEndTag(); // link renderHierarchy(writer, hierarchy, current); writer.RenderEndTag(); // li } } writer.RenderEndTag(); // ul } The ShowMenu method renders the menu out to the provided TextWriter. In previous posts I've discussed my partiality to using well debugged, time test HtmlTextWriter to render HTML rather than writing out angled brackets by hand. In addition, writing out using the actual writer on the actual stream rather than generating string and byte intermediaries (yes, StringBuilder being no exception) disturbs me. To carry out the rendering of an hierarchical menu, the recursive renderHierarchy() is used. You may notice that an ItemFilter is called before rendering each item. I figured that at some point one might want to exclude certain items from the menu based on security role or context or something. That delegate is the hook for such future feature. To carry out rendering of a breadcrumb recursion is used again, this time simply to unwind the parent hierarchy from the leaf node, then rendering on the return from the recursion rather than as we go along deeper. I guess I was stuck in LISP that day.. recursion is fun though.   Now all that is left is some usage! Open your Site.Master or wherever you'd like to place a menu or breadcrumb, and plant one of these calls: <% MvcMenu.ShowBreadCrumb(this.Writer, Request.Url); %> to show a breadcrumb trail (notice lack of "=" after <% and the semicolon). <% MvcMenu.ShowMenu(Writer); %> to show the menu.   As mentioned before, the HTML output is nested <UL> <LI> tags, which should make it easy to style using abundant CSS to produce anything from static horizontal or vertical to dynamic drop-downs.   This has been quite a fun little implementation and I was pleased that the code size remained low. The main crux was figuring out how to pass parent information from the attribute to the hierarchy builder because attributes have restricted parameter types. Once I settled on that implementation, the rest falls into place quite easily.

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• That Escalated Quickly

  - by Jesse Taber

  Originally posted on: http://geekswithblogs.net/GruffCode/archive/2014/05/17/that-escalated-quickly.aspxI have been working remotely out of my home for over 4 years now. All of my coworkers during that time have also worked remotely. Lots of folks have written about the challenges inherent in facilitating communication on remote teams and strategies for overcoming them. A popular theme around this topic is the notion of “escalating communication”. In this context “escalating” means taking a conversation from one mode of communication to a different, higher fidelity mode of communication. Here are the five modes of communication I use at work in order of increasing fidelity: Email – This is the “lowest fidelity” mode of communication that I use. I usually only check it a few times a day (and I’m trying to check it even less frequently than that) and I only keep items in my inbox if they represent an item I need to take action on that I haven’t tracked anywhere else. Forums / Message boards – Being a developer, I’ve gotten into the habit of having other people look over my code before it becomes part of the product I’m working on. These code reviews often happen in “real time” via screen sharing, but I also always have someone else give all of the changes another look using pull requests. A pull request takes my code and lets someone else see the changes I’ve made side-by-side with the existing code so they can see if I did anything dumb. Pull requests can facilitate a conversation about the code changes in an online-forum like style. Some teams I’ve worked on also liked using tools like Trello or Google Groups to have on-going conversations about a topic or task that was being worked on. Chat & Instant Messaging  - Chat and instant messaging are the real workhorses for communication on the remote teams I’ve been a part of. I know some teams that are co-located that also use it pretty extensively for quick messages that don’t warrant walking across the office to talk with someone but reqire more immediacy than an e-mail. For the purposes of this post I think it’s important to note that the terms “chat” and “instant messaging” might insinuate that the conversation is happening in real time, but that’s not always true. Modern chat and IM applications maintain a searchable history so people can easily see what might have been discussed while they were away from their computers. Voice, Video and Screen sharing – Everyone’s got a camera and microphone on their computers now, and there are an abundance of services that will let you use them to talk to other people who have cameras and microphones on their computers. I’m including screen sharing here as well because, in my experience, these discussions typically involve one or more people showing the other participants something that’s happening on their screen. Obviously, this mode of communication is much higher-fidelity than any of the ones listed above. Scheduled meetings are typically conducted using this mode of communication. In Person – No matter how great communication tools become, there’s no substitute for meeting with someone face-to-face. However, opportunities for this kind of communcation are few and far between when you work on a remote team. When a conversation gets escalated that usually means it moves up one or more positions on this list. A lot of people advocate jumping to #4 sooner than later. Like them, I used to believe that, if it was possible, organizing a call with voice and video was automatically better than any kind of text-based communication could be. Lately, however, I’m becoming less convinced that escalating is always the right move. Working Asynchronously Last year I attended a talk at our local code camp given by Drew Miller. Drew works at GitHub and was talking about how they use GitHub internally. Many of the folks at GitHub work remotely, so communication was one of the main themes in Drew’s talk. During the talk Drew used the phrase, “asynchronous communication” to describe their use of chat and pull request comments. That phrase stuck in my head because I hadn’t heard it before but I think it perfectly describes the way in which remote teams often need to communicate. You don’t always know when your co-workers are at their computers or what hours (if any) they are working that day. In order to work this way you need to assume that the person you’re talking to might not respond right away. You can’t always afford to wait until everyone required is online and available to join a voice call, so you need to use text-based, persistent forms of communication so that people can receive and respond to messages when they are available. Going back to my list from the beginning of this post for a second, I characterize items #1-3 as being “asynchronous” modes of communication while we could call items #4 and #5 “synchronous”. When communication gets escalated it’s almost always moving from an asynchronous mode of communication to a synchronous one. Now, to the point of this post: I’ve become increasingly reluctant to escalate from asynchronous to synchronous communication for two primary reasons: 1 – You can often find a higher fidelity way to convey your message without holding a synchronous conversation 2 - Asynchronous modes of communication are (usually) persistent and searchable. You Don’t Have to Broadcast Live Let’s start with the first reason I’ve listed. A lot of times you feel like you need to escalate to synchronous communication because you’re having difficulty describing something that you’re seeing in words. You want to provide the people you’re conversing with some audio-visual aids to help them understand the point that you’re trying to make and you think that getting on Skype and sharing your screen with them is the best way to do that. Firing up a screen sharing session does work well, but you can usually accomplish the same thing in an asynchronous manner. For example, you could take a screenshot and annotate it with some text and drawings to illustrate what it is you’re seeing. If a screenshot won’t work, taking a short screen recording while your narrate over it and posting the video to your forum or chat system along with a text-based description of what’s in the recording that can be searched for later can be a great way to effectively communicate with your team asynchronously. I Said What?!? Now for the second reason I listed: most asynchronous modes of communication provide a transcript of what was said and what decisions might have been made during the conversation. There have been many occasions where I’ve used the search feature of my team’s chat application to find a conversation that happened several weeks or months ago to remember what was decided. Unfortunately, I think the benefits associated with the persistence of communicating asynchronously often get overlooked when people decide to escalate to a in-person meeting or voice/video call. I’m becoming much more reluctant to suggest a voice or video call if I suspect that it might lead to codifying some kind of design decision because everyone involved is going to hang up the call and immediately forget what was decided. I recognize that you can record and archive these types of interactions, but without being able to search them the recordings aren’t terribly useful. When and How To Escalate I don’t mean to imply that communicating via voice/video or in person is never a good idea. I probably jump on a Skype call with a co-worker at least once a day to quickly hash something out or show them a bit of code that I’m working on. Also, meeting in person periodically is really important for remote teams. There’s no way around the fact that sometimes it’s easier to jump on a call and show someone my screen so they can see what I’m seeing. So when is it right to escalate? I think the simplest way to answer that is when the communication starts to feel painful. Everyone’s tolerance for that pain is different, but I think you need to let it hurt a little bit before jumping to synchronous communication. When you do escalate from asynchronous to synchronous communication, there are a couple of things you can do to maximize the effectiveness of the communication: Takes notes – This is huge and yet I’ve found that a lot of teams don’t do this. If you’re holding a meeting with  > 2 people you should have someone taking notes. Taking notes while participating in a meeting can be difficult but there are a few strategies to deal with this challenge that probably deserve a short post of their own. After the meeting, make sure the notes are posted to a place where all concerned parties (including those that might not have attended the meeting) can review and search them. Persist decisions made ASAP – If any decisions were made during the meeting, persist those decisions to a searchable medium as soon as possible following the conversation. All the teams I’ve worked on used a web-based system for tracking the on-going work and a backlog of work to be done in the future. I always try to make sure that all of the cards/stories/tasks/whatever in these systems always reflect the latest decisions that were made as the work was being planned and executed. If held a quick call with your team lead and decided that it wasn’t worth the effort to build real-time validation into that new UI you were working on, go and codify that decision in the story associated with that work immediately after you hang up. Even better, write it up in the story while you are both still on the phone. That way when the folks from your QA team pick up the story to test a few days later they’ll know why the real-time validation isn’t there without having to invoke yet another conversation about the work. Communicating Well is Hard At this point you might be thinking that communicating asynchronously is more difficult than having a live conversation. You’re right: it is more difficult. In order to communicate effectively this way you need to very carefully think about the message that you’re trying to convey and craft it in a way that’s easy for your audience to understand. This is almost always harder than just talking through a problem in real time with someone; this is why escalating communication is such a popular idea. Why wouldn’t we want to do the thing that’s easier? Easier isn’t always better. If you and your team can get in the habit of communicating effectively in an asynchronous manner you’ll find that, over time, all of your communications get less painful because you don’t need to re-iterate previously made points over and over again. If you communicate right the first time, you often don’t need to rehash old conversations because you can go back and find the decisions that were made laid out in plain language. You’ll also find that you get better at doing things like writing useful comments in your code, creating written documentation about how the feature that you just built works, or persuading your team to do things in a certain way.

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