Search Results

Search found 708 results on 29 pages for 'golden gate'.

Page 23/29 | < Previous Page | 19 20 21 22 23 24 25 26 27 28 29  | Next Page >

• F# in ASP.NET, mathematics and testing

  - by DigiMortal

  Starting from Visual Studio 2010 F# is full member of .NET Framework languages family. It is functional language with syntax specific to functional languages but I think it is time for us also notice and study functional languages. In this posting I will show you some examples about cool things other people have done using F#. F# and ASP.NET As I am ASP/ASP.NET MVP I am – of course – interested in how people use different languages and technologies with ASP.NET. C# MVP Tomáš Petrícek writes about developing ASP.NET MVC applications using F#. He also shows how to use LINQ To SQL in F# (using F# PowerPack) and provides sample solution and Visual Studio 2010 template for F# MVC web applications. You may also find interesting how you can create controllers in F#. Excellent work, Tomáš! Vladimir Matveev has interesting example about how to use F# and ApplicationHost class to process ASP.NET requests ouside of IIS. This is simple and very straight-forward example and I strongly suggest you to take a look at it. Very cool example is project Strom in Codeplex. Storm is web services testing tool that is fully written on F#. Take a look at this site because Codeplex offers also source code besides binaries. Math Functional languages are strong in fields like mathematics and physics. When I wrote my C# example about BigInteger class I found out that recursive version of Fibonacci algorithm in C# is not performing well. In same time I made same experiment on F# and in F# there were no performance problems with recursive version. You can find F# version of Fibonacci algorithm from Bob Palmer’s blog posting Fibonacci numbers in F#. Although golden spiral is useful for solving many problems I looked for some practical code example and found one. Kean Walmsley published in his Through the Interface blog very interesting posting Creating Fibonacci spirals in AutoCAD using F#. There are also other cool examples you may be interested in. Using numerical components by Extreme Optimization  it is possible to make some numerical integration (quadrature method) using F# (also C# example is available). fsharp.it introduces factorials calculation on F#. Robert Pickering has made very good work on programming The Game of Life in Silverlight and F# – I definitely suggest you to try out this example as it is very illustrative too. Who wants something more complex may take a look at Newton basin fractal example in F# by Jonathan Birge. Testing After some searching and surfing I found out that there is almost everything available for F# to write tests and test your F# code. FsCheck - FsCheck is a port of Haskell's QuickCheck. Important parts of the manual for using FsCheck is almost literally "adapted" from the QuickCheck manual and paper. Any errors and omissions are entirely my responsibility. FsTest - This project is designed to Language Oriented Programming constructs around unit testing and behavior testing in F#. The goal of this project is to create a Domain Specific Language for testing F# code in a way that makes sense for functional programming. FsUnit - FsUnit makes unit-testing with F# more enjoyable. It adds a special syntax to your favorite .NET testing framework. xUnit.NET - xUnit.net is a developer testing framework, built to support Test Driven Development, with a design goal of extreme simplicity and alignment with framework features. It is compatible with .NET Framework 2.0 and later, and offers several runners: console, GUI, MSBuild, and Visual Studio integration via TestDriven.net, CodeRush Test Runner and Resharper. It also offers test project integration for ASP.NET MVC. Getting started Well, as a first thing you need Visual Studio 2010. Then take a look at these resources: F# samples @ MSDN Microsoft F# Developer Center @ MSDN F# Language Reference @ MSDN F# blog F# forums Real World Functional Programming: With Examples in F# and C# (Amazon) Happy F#-ing! :)

  Read the article

• Application Performance: The Best of the Web

  - by Michaela Murray

  Wisdom A deep understanding and realization […] resulting in the ability to apply perceptions, judgements and actions. It is also the comprehension of what is true coupled with optimum judgment as to action. - Wikipedia We’re writing a book for ASP.NET developers, and we want you to be a part of it. We know that there’s a huge amount of web developer wisdom that never gets shared, and we want to find those golden nuggets of knowledge and experience, and make sure everyone can learn from them. Right now, we want to find out about your top tips, hard-won lessons, and sage advice for avoiding, finding, and fixing application performance problems. If you work with .NET and SQL, even better – a lot of application performance relies on the interaction with the database, so we want to hear from you! “How Do You Want Me To Be Involved?” Right! Details! We want you, our most excellent readers, to email us with the Best Advice you would give to other developers for getting the best performance out of their applications. It doesn’t matter if your advice is for newbies or veterans, .NET or SQL – so long as it’s about application performance, we want to hear from you. (And if you think that there’s developer wisdom out there that “everyone knows”, a) I’m willing to bet you could find someone who doesn’t know about it, and b) it probably bears repeating anyway!) “I’m Interested. What Can You Do For Me?” Excellent question. For starters, there’s a chance to win a Microsoft Surface (the tablet, not the table-top). Once all the ASP.NET Wisdom has been collected, tallied, and labelled, it will then be weighed and measured by a team of expert judges (whose identities are still a closely-guarded secret).  The top tip in both SQL & .NET categories will each win their author their very own MS Surface. But that’s not all! We can also give you… immortality! More details? Ok. We’ll be collecting all of the tips sent in by our readers (and we can’t wait to learn from you all,) and with the help of our Simple-Talk editors, we will publish and distribute your combined and documented knowledge as a free, community-created, professionally typeset eBook. You will naturally be credited by name / pseudonym / twitter handle / GitHub username / StackOverflow profile / Whatever, as the clearly ingenious author of hot performance tips. The Not-Very-Fine Print Here’s the breakdown: We want to bring together the best application performance knowledge from ASP.NET developers. Closing date for submissions will be 9am GMT, December 4th. Submissions should be made by email – [email protected] Submissions will be judged by a panel of expert judges (who will be revealed soon). The top submission in both the SQL & .NET categories will each win a Microsoft Surface. ALL the tips which make it through the judging process will be polished by Simple-Talk editors, and turned into a professionally typeset eBook, which will be freely available, and promoted alongside the ANTS Performance Profiler tool. Anyone whose entry makes it into the book will be clearly and profusely credited in the method of their choice (or can remain anonymous.) The really REALLY short version Share what you know about ASP.NET application performance for a chance to win a Microsoft Surface, and then get your name credited in a slick eBook with top-notch production values. For more details, see above. We can’t wait to learn from you!

  Read the article

• JDK 7u25: Solutions to Issues caused by changes to Runtime.exec

  - by Devika Gollapudi

  The following examples were prepared by Java engineering for the benefit of Java developers who may have faced issues with Runtime.exec on the Windows platform. Background In JDK 7u21, the decoding of command strings specified to Runtime.exec(String), Runtime.exec(String,String[]) and Runtime.exec(String,String[],File) methods, has been made more strict. See JDK 7u21 Release Notes for more information. This caused several issues for applications. The following section describes some of the problems faced by developers and their solutions. Note: In JDK 7u25, the system property jdk.lang.Process.allowAmbigousCommands can be used to relax the checking process and helps as a workaround for some applications that cannot be changed. The workaround is only effective for applications that are run without a SecurityManager. See JDK 7u25 Release Notes for more information. Note: To understand the details of the Windows API CreateProcess call, see: http://msdn.microsoft.com/en-us/library/windows/desktop/ms682425%28v=vs.85%29.aspx There are two forms of Runtime.exec calls: with the command as string: "Runtime.exec(String command[, ...])" with the command as string array: "Runtime.exec(String[] cmdarray [, ...] )" The issues described in this section relate to the first form of call. With the first call form, developers expect the command to be passed "as is" to Windows where the command needs be split into its executable name and arguments parts first. But, in accordance with Java API, the command argument is split into executable name and arguments by spaces. Problem 1: "The file path for the command includes spaces" In the call: Runtime.getRuntime().exec("c:\\Program Files\\do.exe") the argument is split by spaces to an array of strings as: c:\\Program, Files\\do.exe The first element of parsed array is interpreted as the executable name, verified by SecurityManager (if present) and surrounded by quotations to avoid ambiguity in executable path. This results in the wrong command: "c:\\Program" "Files\\do.exe" which will fail. Solution: Use the ProcessBuilder class, or the Runtime.exec(String[] cmdarray [, ...] ) call, or quote the executable path. Where it is not possible to change the application code and where a SecurityManager is not used, the Java property jdk.lang.Process.allowAmbigousCommands could be used by setting its value to "true" from the command line: -Djdk.lang.Process.allowAmbigousCommands=true This will relax the checking process to allow ambiguous input. Examples: new ProcessBuilder("c:\\Program Files\\do.exe").start() Runtime.getRuntime().exec(new String[]{"c:\\Program Files\\do.exe"}) Runtime.getRuntime().exec("\"c:\\Program Files\\do.exe\"") Problem 2: "Shell command/.bat/.cmd IO redirection" The following implicit cmd.exe calls: Runtime.getRuntime().exec("dir temp.txt") new ProcessBuilder("foo.bat", "", "temp.txt").start() Runtime.getRuntime().exec(new String[]{"foo.cmd", "", "temp.txt"}) lead to the wrong command: "XXXX" "" temp.txt Solution: To specify the command correctly, use the following options: Runtime.getRuntime().exec("cmd /C \"dir temp.txt\"") new ProcessBuilder("cmd", "/C", "foo.bat temp.txt").start() Runtime.getRuntime().exec(new String[]{"cmd", "/C", "foo.cmd temp.txt"}) or Process p = new ProcessBuilder("cmd", "/C" "XXX").redirectOutput(new File("temp.txt")).start(); Problem 3: "Group execution of shell command and/or .bat/.cmd files" Due to enforced verification procedure, arguments in the following calls create the wrong commands.: Runtime.getRuntime().exec("first.bat && second.bat") new ProcessBuilder("dir", "&&", "second.bat").start() Runtime.getRuntime().exec(new String[]{"dir", "|", "more"}) Solution: To specify the command correctly, use the following options: Runtime.exec("cmd /C \"first.bat && second.bat\"") new ProcessBuilder("cmd", "/C", "dir && second.bat").start() Runtime.exec(new String[]{"cmd", "/C", "dir | more"}) The same scenario also works for the "&", "||", "^" operators of the cmd.exe shell. Problem 4: ".bat/.cmd with special DOS chars in quoted params” Due to enforced verification, arguments in the following calls will cause exceptions to be thrown.: Runtime.getRuntime().exec("log.bat \"error new ProcessBuilder("log.bat", "error Runtime.getRuntime().exec(new String[]{"log.bat", "error Solution: To specify the command correctly, use the following options: Runtime.getRuntime().exec("cmd /C log.bat \"error new ProcessBuilder("cmd", "/C", "log.bat", "error Runtime.getRuntime().exec(new String[]{"cmd", "/C", "log.bat", "error Examples: Complicated redirection for shell construction: cmd /c dir /b C:\ "my lovely spaces.txt" becomes Runtime.getRuntime().exec(new String[]{"cmd", "/C", "dir \b \"my lovely spaces.txt\"" }); The Golden Rule: In most cases, cmd.exe has two arguments: "/C" and the command for interpretation.

  Read the article

• BI&EPM in Focus June 2012

  - by Mike.Hallett(at)Oracle-BI&EPM

  General News Thomas Kurian Discusses Oracle Exalytics, SAP HANA (replay | preso | press)  Accenture & Oracle Study: The Challenges of Corporate Financial Reporting  (link) Flash Demo: Oracle Hyperion Planning on Exalytics in the Public Sector (link) Flash Demo: OBIEE & Exalytics in Retail (link) Customers Italian Partner Alfa Sistemi implemented at Autovie Venete S.p.A. Integrates Business Intelligence and Performance Management to Improve Efficiency and Speed for Managing Public Works Projects (English version)  / Autovie Venete implementa un sistema integrato di Business Intelligence e Performance Management per migliorare l’efficienza e la tempestività dell’attività di Controlling di Commessa (Italian version). FANCL Gains 360-Degree View of Customers across Multiple Sales Channels, Reduces Reports by 75% Korea Yakult Improves Profit & Loss Analysis with Oracle Hyperion Planning and OBIEE Hill International Streamlines Forecasting, Improves Visibility into Project Productivity and Profitability Children’s Rights in Society Better Supports Organizational Mission with Advanced, Integrated, and Streamlined Business Intelligence Tools Profit: International utility Enel monitors the performance of global subsidiaries with Oracle Hyperion Applications (link) Profit: Charting a New Course: Korean Air gains altitude by leveraging its greatest asset: information (link)   Events June 12: Breaking Away from the Excel Add-In: Welcome to Hyperion Smart View 11.1.2.2 (link) June 13: Upgrading OBIEE 10g to 11g: Best Practices and Lessons Learned (performance architects) (link) June 14, The Netherlands: Strategies for Business Excellence, New Release of Oracle Hyperion EPM Suite (link) June 21: Comprehensive and Accurate Forecasting for Healthcare (link) June 26: What Exactly is Exalytics? (KPI Partners) (link) Webcast Replay: Is Your Company Able to Navigate Through Market Volatility? (link)  Webcast Replay: Is Hope and Email The Core of Your Reconciliation Process? (link) Webcast Replay: Troubleshooting EPM Reporting & Analysis 11.1.2.x  (link) Webcast Replay: Is your Organization Flying Blind when it comes to Understanding Profitability?  (link) Enterprise Performance Management Final Oracle EPM  Information Panel (CIP) survey on cost, profitability and performance reporting/scorecards is now OPEN (link) New on EPM Blog: What's Going on With IFRS? (link) How does Crystal Ball integrate with EPM Solutions? New collateral and demos on Crystal Ball Solution Factory!  (link) New Youtube Video: Business Case Analysis with Oracle Crystal Ball (link) Crystal Ball 11.1.2.2 is released! Grouped Assumptions in Sensitivity Charts, Data Filtering When Fitting Distributions and Parameter Edits When Fitting Distributions to name a few. Get full details from the online New Features Guide (link) New DRM Oracle-by-Examples now available (link) Support Blog: Hyperion Ledgerlink Sample Record and Windows 7: Now you see it, now you don’t  (link) Use Enterprise Manager FMW Control to Troubleshoot Oracle EPM 11.1.2 Family of Products (link) Business  Intelligence Whitepaper: Real-Time Operational Reporting for E-Business Suite via GoldenGate Replication to an Operational Data Store.  How Oracle enabled real-time operational reporting for its $20B services contract business with Golden Gate & OBIEE (link) KPI Partners ebook: Understanding Oracle BI Components and Repository Modeling Basics (link) “Getting Started with Oracle Endeca Information Discovery” video tutorials now available (link) Oracle BI Publisher Conversion Center: Convert from Crystal, Actuate, or Oracle Reports to Oracle BI Publisher (link) Oracle Fusion Applications: Monthly Partner Updates Webcast Replays to help BI partners understand how OBI, Essbase, BI-Apps and Fusion work together: More on Fusion CRM: Fusion Marketing More on Fusion CRM: Fusion CRM Sales Start-Up Packs and Expert Services for Implementation Partners Introducing the Oracle Fusion Accounting Hub Implementing Fusion Applications using Oracle's Composers Oracle Fusion Applications Co-Existence

  Read the article

• How the number of indexes built on a table can impact performances?

  - by Davide Mauri

  We all know that putting too many indexes (I’m talking of non-clustered index only, of course) on table may produce performance problems due to the overhead that each index bring to all insert/update/delete operations on that table. But how much? I mean, we all agree – I think – that, generally speaking, having many indexes on a table is “bad”. But how bad it can be? How much the performance will degrade? And on a concurrent system how much this situation can also hurts SELECT performances? If SQL Server take more time to update a row on a table due to the amount of indexes it also has to update, this also means that locks will be held for more time, slowing down the perceived performance of all queries involved. I was quite curious to measure this, also because when teaching it’s by far more impressive and effective to show to attended a chart with the measured impact, so that they can really “feel” what it means! To do the tests, I’ve create a script that creates a table (that has a clustered index on the primary key which is an identity column) , loads 1000 rows into the table (inserting 1000 row using only one insert, instead of issuing 1000 insert of one row, in order to minimize the overhead needed to handle the transaction, that would have otherwise ), and measures the time taken to do it. The process is then repeated 16 times, each time adding a new index on the table, using columns from table in a round-robin fashion. Test are done against different row sizes, so that it’s possible to check if performance changes depending on row size. The result are interesting, although expected. This is the chart showing how much time it takes to insert 1000 on a table that has from 0 to 16 non-clustered indexes. Each test has been run 20 times in order to have an average value. The value has been cleaned from outliers value due to unpredictable performance fluctuations due to machine activity. The test shows that in a  table with a row size of 80 bytes, 1000 rows can be inserted in 9,05 msec if no indexes are present on the table, and the value grows up to 88 (!!!) msec when you have 16 indexes on it This means a impact on performance of 975%. That’s *huge*! Now, what happens if we have a bigger row size? Say that we have a table with a row size of 1520 byte. Here’s the data, from 0 to 16 indexes on that table: In this case we need near 22 msec to insert 1000 in a table with no indexes, but we need more that 500msec if the table has 16 active indexes! Now we’re talking of a 2410% impact on performance! Now we can have a tangible idea of what’s the impact of having (too?) many indexes on a table and also how the size of a row also impact performances. That’s why the golden rule of OLTP databases “few indexes, but good” is so true! (And in fact last week I saw a database with tables with 1700bytes row size and 23 (!!!) indexes on them!) This also means that a too heavy denormalization is really not a good idea (we’re always talking about OLTP systems, keep it in mind), since the performance get worse with the increase of the row size. So, be careful out there, and keep in mind the “equilibrium” is the key world of a database professional: equilibrium between read and write performance, between normalization and denormalization, between to few and too may indexes. PS Tests are done on a VMWare Workstation 7 VM with 2 CPU and 4 GB of Memory. Host machine is a Dell Precsioni M6500 with i7 Extreme X920 Quad-Core HT 2.0Ghz and 16Gb of RAM. Database is stored on a SSD Intel X-25E Drive, Simple Recovery Model, running on SQL Server 2008 R2. If you also want to to tests on your own, you can download the test script here: Open TestIndexPerformance.sql

  Read the article

• What Counts for a DBA: Skill

  - by drsql

  “Practice makes perfect:” right? Well, not exactly. The reality of it all is that this saying is an untrustworthy aphorism. I discovered this in my “younger” days when I was a passionate tennis player, practicing and playing 20+ hours a week. No matter what my passion level was, without some serious coaching (and perhaps a change in dietary habits), my skill level was never going to rise to a level where I could make any money at the sport that involved something other than selling tennis balls at a sporting goods store. My game may have improved with all that practice but I had too many bad practices to overcome. Practice by itself merely reinforces what we know and what we can figure out naturally. The truth is actually closer to the expression used by Vince Lombardi: “Perfect practice makes perfect.” So how do you get to become skilled as a DBA if practice alone isn’t sufficient? Hit the Internet and start searching for SQL training and you can find 100 different sites. There are also hundreds of blogs, magazines, books, conferences both onsite and virtual. But then how do you know who is good? Unfortunately often the worst guide can be to find out the experience level of the writer. Some of the best DBAs are frighteningly young, and some got their start back when databases were stored on stacks of paper with little holes in it. As a programmer, is it really so hard to understand normalization? Set based theory? Query optimization? Indexing and performance tuning? The biggest barrier often is previous knowledge, particularly programming skills cultivated before you get started with SQL. In the world of technology, it is pretty rare that a fresh programmer will gravitate to database programming. Database programming is very unsexy work, because without a UI all you have are a bunch of text strings that you could never impress anyone with. Newbies spend most of their time building UIs or apps with procedural code in C# or VB scoring obvious interesting wins. Making matters worse is that SQL programming requires mastery of a much different toolset than most any mainstream programming skill. Instead of controlling everything yourself, most of the really difficult work is done by the internals of the engine (written by other non-relational programmers…we just can’t get away from them.) So is there a golden road to achieving a high skill level? Sadly, with tennis, I am pretty sure I’ll never discover it. However, with programming it seems to boil down to practice in applying the appropriate techniques for whatever type of programming you are doing. Can a C# programmer build a great database? As long as they don’t treat SQL like C#, absolutely. Same goes for a DBA writing C# code. None of this stuff is rocket science, as long as you learn to understand that different types of programming require different skill sets and you as a programmer must recognize the difference between one of the procedural languages and SQL and treat them differently. Skill comes from practicing doing things the right way and making “right” a habit.

  Read the article

• iPhone Inspiration Stories...

  - by Luis Tovar

  So we have all heard of these overnight millionaires in the app store. We know it would be great, but somewhat unlikely to do ourselves. What I do know is, that learning and developing for the iPhone can sometimes be overwhelming. I continue to push on and learn more and more, even when my brain just cant take anymore I turn my mac on and read up on how to do new and different things I haven't done yet in my app yet. I would like to see a few post's of a common day developer's story and how their life has improved now that they are sitting up on the golden pedestal of an iphone developer. I look at these Dice.com jobs on think how nice it would be to be making that kind of money offered for an experienced iphone developer. Im on my way... and while I'm on that road i'd like to look over and see your story... Please include how you got into iPhone development and any apps you have out there and your success with them. Care to share?

  Read the article

• conditionals for C++ using MSBuild/vsbuild?

  - by redtuna

  I have a C++ project in Visual Studio 2008 and I'd like to be able to compile several versions from the command line, defining conditional variables (aka #define). If it were just a single file to compile I'd use something like cl /D, but this is complex enough that I would like to be able to use VS's other features like the build order etc. I've seen a similar question asked in stackoverflow and the answer was to use /p:DefineConstants="var1;var2". This doesn't seem to work with C++ though. The other problem with that answer is that it replaces the conditional variables, instead of adding to them. The vcproj files for C++ look quite different. If msbuild (or vsbuild) had a way to change Configurations/Tool[name="VCCLCompilerTool"] we'd be golden. But I haven't found such an option. The vcproj files are under source control so I'd rather not have a script mess with them. I've considered doubling the number of configurations (one with the #define, one without). That'd be annoying, and I'm especially unhappy with having to modify these configurations in tandem every time I need to modify anything there. A previous similar question found no solution. I'm hoping that has changed since? How would you go about building those variants (with and without define) from the command line? Thanks!

  Read the article

• Detecting death of spawned process using Window CRT

  - by Michael Tiller

  Executive summary: I need a way to determine whether a Windows process I've spawned via _spawnl and am communicating with using FDs from _pipe has died. Details: I'm using the low-level CRT function in Windows (_eof, _read) to communicate with a process that was spawned via a call to _spawnl (with the P_NOWAIT) flag. I'm using _pipe to create file descriptors to communicate with this spawned process and passing those descriptors (the FD #) to it on the command line. It is worth mentioning that I don't control the spawned process. It's a black box to me. It turns out that the process we are spawning occasionally crashes. I'm trying to make my code robust to this by detecting the crash. Unfortunately, I can't see a way to do this. It seems reasonable to me to expect that a call to _eof or _read on one of those descriptors would return an error status (-1) if the process had died. Unfortunately, that isn't the case. It appears that the descriptors have a life of their own independent of the spawned process. So even though the process on the other end is dead, I get no error status on the file descriptor I'm using to communicate with it. I've got the PID for the nested process (returned from the _spanwnl call) but I don't see anything I can do with that. My code works really well except for one thing. I can't detect whether the spawned process is simply busy computing me an answer or has died. If I can use the information from _pipe and _spawnl to determine if the spawned process is dead, I'll be golden. Suggestions very welcome. Thanks in advance. UPDATE: I found a fairly simple solution and added it as the selected answer.

  Read the article

• Where do you take mocking - immediate dependencies, or do you grow the boundaries...?

  - by Peter Mounce

  So, I'm reasonably new to both unit testing and mocking in C# and .NET; I'm using xUnit.net and Rhino Mocks respectively. I'm a convert, and I'm focussing on writing behaviour specifications, I guess, instead of being purely TDD. Bah, semantics; I want an automated safety net to work above, essentially. A thought struck me though. I get programming against interfaces, and the benefits as far as breaking apart dependencies goes there. Sold. However, in my behaviour verification suite (aka unit tests ;-) ), I'm asserting behaviour one interface at a time. As in, one implementation of an interface at a time, with all of its dependencies mocked out and expectations set up. The approach seems to be that if we verify that a class behaves as it should against its collaborating dependencies, and in turn relies on each of those collaborating dependencies to have signed that same quality contract, we're golden. Seems reasonable enough. Back to the thought, though. Is there any value in semi-integration tests, where a test-fixture is asserting against a unit of concrete implementations that are wired together, and we're testing its internal behaviour against mocked dependencies? I just re-read that and I think I could probably have worded it better. Obviously, there's going to be a certain amount of "well, if it adds value for you, keep doing it", I suppose - but has anyone else thought about doing that, and reaped benefits from it outweighing the costs?

  Read the article

• Modify post data with a custom MVC extension?

  - by Jaxidian

  So I'm looking into writing some custom MVC extensions and the first one I'm attempting to tackle is a FormattedTextBox to handle things such as currency, dates, and times. I have the rendering of it working perfectly, formatting it, working with strong types and everything all golden. However, the problem I'm now running into is cleaning up the formatted stuff when the page posts the data back. Take for example, a currency format. Let's use USD for these examples. When an object has a property as a decimal, the value would be 79.95. Your edit view would be something like: <%= Html.FormattedTextBox(model => Model.Person.HourlyWage, "{0:C}") %> This is all well and good for the GET request, but upon POST, the value is going to be $79.95, which when you assign to that decimal, gets unhappy very quickly and ends up shoving a 0 in there. So my question is, how do I get code working somewhere to work with that value before the MVC Framework goes and starts shoving it back into my ViewModel? I'd much rather this be done server-side than client-side. Thanks!!

  Read the article

• How 'terse' is too terse? -- Practical guidelines for expressing as much intent in as few characters

  - by Christopher Altman

  First, I love writing as little code as possible. I think, and please correct me, one of the golden rules of programming is to express your code in as few of character as possible while maintaining human readability. But I can get a little carried away. I can pack three or four lines into one statement, something like $startDate = $dateTime > time() ? mktime(0,0,0,date('m',time()-86400),date('d',time()*2),2011) : time(); (Note: this is a notional example) I can comprehend the above code when reading it. I prefer 'mushing' it all together because having less lines per page is a good thing to me. So my question: When writing code and thinking about how compact or terse you can express yourself, what are some guidelines you use? Do you write multiple lines because you think it helps other people? Do you write as little as possible, but use comments? Or do you always look for the way to write as little code as possible and enjoy the rewards of compact statements? (Just one slightly off topic comment: I love the Perl one-liners, but that is not what I am talking about here)

  Read the article

• Create an instance of an exported C++ class from Delphi

  - by Alan G.

  I followed an excellent article by Rudy Velthuis about using C++ classes in DLL's. Everything was golden, except that I need access to some classes that do not have corresponding factories in the C++ DLL. How can I construct an instance of a class in the DLL? The classes in question are defined as class __declspec(dllexport) exampleClass { public: void foo(); }; Now without a factory, I have no clear way of instantiating the class, but I know it can be done, as I have seen SWIG scripts (.i files) that make these classes available to Python. If Python&SWIG can do it, then I presume/hope there is some way to make it happen in Delphi too. Now I don't know much about SWIG, but it seems like it generates some sort of map for C++ mangled names? Is that anywhere near right? Looking at the exports from the DLL, I suppose I could access functions & constructor/destructor by index or the mangled name directly, but that would be nasty; and would it even work? Even if I can call the constructor, how can I do the equivalent of "new CClass();" in Delphi?

  Read the article

• Division by zero: Undefined Behavior or Implementation Defined in C and/or C++ ?

  - by SiegeX

  Regarding division by zero, the standards say: C99 6.5.5p5 - The result of the / operator is the quotient from the division of the first operand by the second; the result of the % operator is the remainder. In both operations, if the value of the second operand is zero, the behavior is undefined. C++03 5.6.4 - The binary / operator yields the quotient, and the binary % operator yields the remainder from the division of the first expression by the second. If the second operand of / or % is zero the behavior is undefined. If we were to take the above paragraphs at face value, the answer is clearly Undefined Behavior for both languages. However, if we look further down in the C99 standard we see the following paragraph which appears to be contradictory(1): C99 7.12p4 - The macro INFINITY expands to a constant expression of type float representing positive or unsigned infinity, if available; Do the standards have some sort of golden rule where Undefined Behavior cannot be superseded by a (potentially) contradictory statement? Barring that, I don't think it's unreasonable to conclude that if your implementation defines the INFINITY macro, division by zero is defined to be such. However, if your implementation does not define such a macro, the behavior is Undefined. I'm curious what the consensus on this matter for each of the two languages. Would the answer change if we are talking about integer division int i = 1 / 0 versus floating point division float i = 1.0 / 0.0 ? Note (1) The C++03 standard talks about the library which includes the INFINITY macro.

  Read the article

• How do I make this nested for loop, testing sums of cubes, more efficient?

  - by Brian J. Fink

  I'm trying to iterate through all the combinations of pairs of positive long integers in Java and testing the sum of their cubes to discover if it's a Fibonacci number. I'm currently doing this by using the value of the outer loop variable as the inner loop's upper limit, with the effect being that the outer loop runs a little slower each time. Initially it appeared to run very quickly--I was up to 10 digits within minutes. But now after 2 full days of continuous execution, I'm only somewhere in the middle range of 15 digits. At this rate it may end up taking a whole year just to finish running this program. The code for the program is below: import java.lang.*; import java.math.*; public class FindFib { public static void main(String args[]) { long uLimit=9223372036854775807L; //long maximum value BigDecimal PHI=new BigDecimal(1D+Math.sqrt(5D)/2D); //Golden Ratio for(long a=1;a<=uLimit;a++) //Outer Loop, 1 to maximum for(long b=1;b<=a;b++) //Inner Loop, 1 to current outer { //Cube the numbers and add BigDecimal c=BigDecimal.valueOf(a).pow(3).add(BigDecimal.valueOf(b).pow(3)); System.out.print(c+" "); //Output result //Upper and lower limits of interval for Mobius test: [c*PHI-1/c,c*PHI+1/c] BigDecimal d=c.multiply(PHI).subtract(BigDecimal.ONE.divide(c,BigDecimal.ROUND_HALF_UP)), e=c.multiply(PHI).add(BigDecimal.ONE.divide(c,BigDecimal.ROUND_HALF_UP)); //Mobius test: if integer in interval (floor values unequal) Fibonacci number! if (d.toBigInteger().compareTo(e.toBigInteger())!=0) System.out.println(); //Line feed else System.out.print("\r"); //Carriage return instead } //Display final message System.out.println("\rDone. "); } } Now the use of BigDecimal and BigInteger was delibrate; I need them to get the necessary precision. Is there anything other than my variable types that I could change to gain better efficiency?

  Read the article

• Index question: Select * with WHERE clause. Where and how to create index

  - by Mestika

  Hi, I’m working on optimizing some of my queries and I have a query that states: select * from SC where c_id ="+c_id” The schema of ** SC** looks like this: SC ( c_id int not null, date_start date not null, date_stop date not null, r_t_id int not null, nt int, t_p decimal, PRIMARY KEY (c_id, r_t_id, date_start, date_stop)); My immediate bid on how the index should be created is a covering index in this order: INDEX(c_id, date_start, date_stop, nt, r_t_id, t_p) The reason for this order I base on: The WHERE clause selects from c_id thus making it the first sorting order. Next, the date_start and date_stop to specify a sort of “range” to be defined in these parameters Next, nt because it will select the nt Next the r_t_id because it is a ID for a specific type of my r_t table And last the t_p because it is just a information. I don’t know if it is at all necessary to order it in a specific way when it is a SELECT ALL statement. I should say, that the SC is not the biggest table. I can say how many rows it contains but a estimate could be between <10 and 1000. The next thing to add is, that the SC, in different queries, inserts the data into the SC, and I know that indexes on tables which have insertions can be cost ineffective, but can I somehow create a golden middle way to effective this performance. Don't know if it makes a different but I'm using IBM DB2 version 9.7 database Sincerely Mestika

  Read the article

• How to "upgrade" the database in real world?

  - by Tattat

  My company have develop a web application using php + mysql. The system can display a product's original price and discount price to the user. If you haven't logined, you get the original price, if you loginned , you get the discount price. It is pretty easy to understand. But my company want more features in the system, it want to display different prices base on different user. For example, user A is a golden parnter, he can get 50% off. User B is a silver parnter, only have 30 % off. But this logic is not prepare in the original system, so I need to add some attribute in the database, at least a user type in this example. Is there any recommendation on how to merge current database to my new version of database. Also, all the data should preserver, and the server should works 24/7. (within stop the database) Is it possible to do so? Also , any recommend for future maintaince advice? Thz u.

  Read the article

• How can I determine the "correct" number of steps in a questionnaire where branching is used?

  - by Mike Kingscott

  I have a potential maths / formula / algorithm question which I would like help on. I've written a questionnaire application in ASP.Net that takes people through a series of pages. I've introduced conditional processing, or branching, so that some pages can be skipped dependent on an answer, e.g. if you're over a certain age, you will skip the page that has Teen Music Choice and go straight to the Golden Oldies page. I wish to display how far along the questionnaire someone is (as a percentage). Let's say I have 10 pages to go through and my first answer takes me straight to page 9. Technically, I'm now 90% of the way through the questionnaire, but the user can think of themselves as being on page 2 of 3: the start page (with the branching question), page 9, then the end page (page 10). How can I show that I'm on 66% and not 90% when I'm on page 9 of 10? For further information, each Page can have a number of questions on that can have one or more conditions on them that will send the user to another page. By default, the next page will be the next one in the collection, but that can be over-ridden (e.g. entire sets of pages can be skipped). Any thoughts? :-s

  Read the article

• Is std::move really needed on initialization list of constructor for heavy members passed by value?

  - by PiotrNycz

  Recently I read an example from cppreference.../vector/emplace_back: struct President { std::string name; std::string country; int year; President(std::string p_name, std::string p_country, int p_year) : name(std::move(p_name)), country(std::move(p_country)), year(p_year) { std::cout << "I am being constructed.\n"; } My question: is this std::move really needed? My point is that compiler sees that this p_name is not used in the body of constructor, so, maybe, there is some rule to use move semantics for it by default? That would be really annoying to add std::move on initialization list to every heavy member (like std::string, std::vector). Imagine hundreds of KLOC project written in C++03 - shall we add everywhere this std::move? This question: move-constructor-and-initialization-list answer says: As a golden rule, whenever you take something by rvalue reference, you need to use it inside std::move, and whenever you take something by universal reference (i.e. deduced templated type with &&), you need to use it inside std::forward But I am not sure: passing by value is rather not universal reference?

  Read the article

• Extract information from a Func<bool, T> or alike lambda

  - by Syska

  I''m trying to build a generic cache layer. ICacheRepository Say I have the following: public class Person { public int PersonId { get; set; } public string Firstname { get; set; } public string Lastname { get; set; } public DateTime Added { get; set; } } And I have something like this: list.Where(x => x.Firstname == "Syska"); Here I want to extract the above information, to see if the query supplied the "PersonId" which it did not, so I dont want to cache it. But lets say I run a query like this: list.Where(x => x.PersonId == 10); Since PersonId is my key ... I want to cache it. with the key like "Person_10" and I later can fetch it from the cache. I know its possible to extract the information with Expression<Func<>> but there seems to be a big overhead of doing this (when running compile and extract the Constant values etc. and a bunch of cache to be sure to parse right) Are there a framework for this? Or some smart/golden way of doing this ?

  Read the article

• How do I deal with different requests that map to the same response?

  - by daxim

  I'm designing a Web service. The request is idempotent, so I chose the GET method. The response is relatively expensive to calculate and not small, so I want to get caching (on the protocol level) right. (Don't worry about memoisation at my part, I have that already covered; my question here is actually also paying attention to the Web as a whole.) There's only one mandatory parameter and a number of optional parameter with default values if missing. For example, the following two map to the same representation of the response. (If this is a dumb way to go about it the interface, propose something better.) GET /service?mandatory_parameter=some_data HTTP/1.1 GET /service?mandatory_parameter=some_data;optional_parameter=default1;another_optional_parameter=default2;yet_another_optional_parameter=default3 HTTP/1.1 However, I imagine clients do not know this and would treat them separate and therefore waste cache storage. What should I do to avoid violating the golden rule of caching? Make up a canonical form, document it (e.g. all parameters are required after all and need to be sorted in a specific order) and return a client error unless the required form is met? Instead of an error, redirect permanently to the canonical form of a request? Or is it enough to not mind how the request looks like, and just respond with the same ETag for same responses?

  Read the article

• ELF: linking: Why do I get undefined references in .so files

  - by ki.lya.online.fr

  Hi, I'm trying to build a program against wxWidgets, and I get a linker error. I'd like to really understand what it means. The error is: /usr/lib/libwx_baseu-2.8.so: undefined reference to `std::ctype<char>::_M_widen_init() const@GLIBCXX_3.4.11' What I don't understand is why the error is at libwx_baseu-2.8.so. I thought that .so files had all its symbols resolved, contrary to .o files that still need linking. When I ldd the .so, I get can resolve all its linked libraries, so there is no problem there: $ ldd /usr/lib/libwx_baseu-2.8.so linux-gate.so.1 => (0x00476000) libz.so.1 => /lib/libz.so.1 (0x00d9c000) libdl.so.2 => /lib/libdl.so.2 (0x002a8000) libm.so.6 => /lib/libm.so.6 (0x00759000) libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x002ad000) libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x0068d000) libpthread.so.0 => /lib/libpthread.so.0 (0x006f0000) libc.so.6 => /lib/libc.so.6 (0x00477000) /lib/ld-linux.so.2 (0x007f6000) Does it means that the .so file was not compiled correctly (in that case, it's a bug in my distribution package) or does it means that there are missing libraries on the linker command line for my particular program? Additionally, do you know how I can get a list on undefined symbols in an ELF file. I tried readelf -s but I can't find the missing symbol. Thank you. Mildred

  Read the article

• Can a call to WaitHandle.SignalAndWait be ignored for performance profiling purposes?

  - by Dan Tao

  I just downloaded the trial version of ANTS Performance Profiler from Red Gate and am investigating some of my team's code. Immediately I notice that there's a particular section of code that ANTS is reporting as eating up to 99% CPU time. I am completely unfamiliar with ANTS or performance profiling in general (that is, aside from self-profiling using what I'm sure are extremely crude and frowned-upon methods such as double timeToComplete = (endTime - startTime).TotalSeconds), so I'm still fiddling around with the application and figuring out how it's used. But I did call the developer responsible for the code in question and his immediate reaction was "Yeah, that doesn't surprise me that it says that; but that code calls SignalAndWait [which I could see for myself, thanks to ANTS], which doesn't use any CPU, it just sits there waiting for something to do." He advised me to simply ignore that code and look for anything ELSE I could find. My question: is it true that SignalAndWait requires NO CPU overhead (and if so, how is this possible?), and is it reasonable that a performance profiler would view it as taking up 99% CPU time? I find this particularly curious because, if it's at 99%, that would suggest that our application is often idle, wouldn't it? And yet its performance has become rather sluggish lately. Like I said, I really am just a beginner when it comes to this tool, and I don't know anything about the WaitHandle class. So ANY information to help me to understand what's going on here would be appreciated.

  Read the article

• Which knowledge base/rule-based inference engine to choose for real time Runway incursion prevention

  - by Piligrim

  Hello, we are designing a project that would listen to dialog between airport controllers and pilots to prevent runway incursions (eg. one airplane is taking off while other is crossing the runway). Our professor wants us to use Jena for knowledge base (or anything else but it should be some sort of rule-based engine). Inference is not the main thing in Jena and there's not much documentation and examples of this. So we need an engine that would get messages from pilots as input and output possible risks of incursion or any other error in message protocol. It should be easy to write rules, and should be easy to provide engine with real time data. I image it something like this: A pilot sends a message that he lands on some runway, the system remembers that the runway is busy and no one should cross it If someone is given an instruction to cross this runway, the engine should fire a rule that something is wrong When the pilot sends a message that he left the runway and goes to the gate, the system clears the runway and lets other planes to use it. So is Jena, or prolog or any other rules engine suitable for this? I mean it is suitable, but do we really need to use it? I asked the prof. if we could just keep state of the runway and use some simple checks based on messages we receive and he said that it is not scalable and we need the knowledge base. Can someone give me any advise on which approach to use for this system? If you recommend k.b., then which one should we use? The project is written in java. Thank you.

  Read the article

• Finding missing symbols in libstd++ on Debian/squeeze

  - by Florian Le Goff

  I'm trying to use a pre-compiled library provided as a .so file. This file is dynamically linked against a few librairies : $ ldd /usr/local/test/lib/libtest.so linux-gate.so.1 = (0xb770d000) libstdc++-libc6.1-1.so.2 = not found libm.so.6 = /lib/i686/cmov/libm.so.6 (0xb75e1000) libc.so.6 = /lib/i686/cmov/libc.so.6 (0xb7499000) /lib/ld-linux.so.2 (0xb770e000) libgcc_s.so.1 = /lib/libgcc_s.so.1 (0xb747c000) Unfortunately, in Debian/squeeze, there is no libstdc++-libc6.1-1.so.* file. Only a libstdc++.so.* file provided by the libstdc++6 package. I tried to link (using ln -s) libstdc++-libc6.1-1.so.2 to the libstdc++.so.6 file. It does not work, a batch of symbols seems to be lacking when I'm trying to ld my .o files with this lib. /usr/local/test/lib/libtest.so: undefined reference to `__builtin_vec_delete' /usr/local/test/lib/libtest.so: undefined reference to `istrstream::istrstream(int, char const *, int)' /usr/local/test/lib/libtest.so: undefined reference to `__rtti_user' /usr/local/test/lib/libtest.so: undefined reference to `__builtin_new' /usr/local/test/lib/libtest.so: undefined reference to `istream::ignore(int, int)' What would you do ? How may I find in which lib those symbols are exported ?

  Read the article

< Previous Page | 19 20 21 22 23 24 25 26 27 28 29  | Next Page >