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• readonly keyword

  - by nmarun

  This is something new that I learned about the readonly keyword. Have a look at the following class: 1: public class MyClass 2: { 3: public string Name { get; set; } 4: public int Age { get; set; } 5:  6: private readonly double Delta; 7:  8: public MyClass() 9: { 10: Initializer(); 11: } 12:  13: public MyClass(string name = "", int age = 0) 14: { 15: Name = name; 16: Age = age; 17: Initializer(); 18: } 19:  20: private void Initializer() 21: { 22: Delta = 0.2; 23: } 24: } I have a couple of public properties and a private readonly member. There are two constructors – one that doesn’t take any parameters and the other takes two parameters to initialize the public properties. I’m also calling the Initializer method in both constructors to initialize the readonly member. Now when I build this, the code breaks and the Error window says: “A readonly field cannot be assigned to (except in a constructor or a variable initializer)” Two things after I read this message: It’s such a negative statement. I’d prefer something like: “A readonly field can be assigned to (or initialized) only in a constructor or through a variable initializer” But in my defense, I AM assigning it in a constructor (only indirectly). All I’m doing is creating a method that does it and calling it in a constructor. Turns out, .net was not ‘frameworked’ this way. We need to have the member initialized directly in the constructor. If you have multiple constructors, you can just use the ‘this’ keyword on all except the default constructors to call the default constructor. This default constructor can then initialize your readonly members. This will ensure you’re not repeating the code in multiple places. A snippet of what I’m talking can be seen below: 1: public class Person 2: { 3: public int UniqueNumber { get; set; } 4: public string Name { get; set; } 5: public int Age { get; set; } 6: public DateTime DateOfBirth { get; set; } 7: public string InvoiceNumber { get; set; } 8:  9: private readonly string Alpha; 10: private readonly int Beta; 11: private readonly double Delta; 12: private readonly double Gamma; 13:  14: public Person() 15: { 16: Alpha = "FDSA"; 17: Beta = 2; 18: Delta = 3.0; 19: Gamma = 0.0989; 20: } 21:  22: public Person(int uniqueNumber) : this() 23: { 24: UniqueNumber = uniqueNumber; 25: } 26: } See the syntax in line 22 and you’ll know what I’m talking about. So the default constructor gets called before the one in line 22. These are known as constructor initializers and they allow one constructor to call another. The other ‘myth’ I had about readonly members is that you can set it’s value only once. This was busted as well (I recall Adam and Jamie’s show). Say you’ve initialized the readonly member through a variable initializer. You can over-write this value in any of the constructors any number of times. 1: public class Person 2: { 3: public int UniqueNumber { get; set; } 4: public string Name { get; set; } 5: public int Age { get; set; } 6: public DateTime DateOfBirth { get; set; } 7: public string InvoiceNumber { get; set; } 8:  9: private readonly string Alpha = "asdf"; 10: private readonly int Beta = 15; 11: private readonly double Delta = 0.077; 12: private readonly double Gamma = 1.0; 13:  14: public Person() 15: { 16: Alpha = "FDSA"; 17: Beta = 2; 18: Delta = 3.0; 19: Gamma = 0.0989; 20: } 21:  22: public Person(int uniqueNumber) : this() 23: { 24: UniqueNumber = uniqueNumber; 25: Beta = 3; 26: } 27:  28: public Person(string name, DateTime dob) : this() 29: { 30: Name = name; 31: DateOfBirth = dob; 32:  33: Alpha = ";LKJ"; 34: Gamma = 0.0898; 35: } 36:  37: public Person(int uniqueNumber, string name, int age, DateTime dob, string invoiceNumber) : this() 38: { 39: UniqueNumber = uniqueNumber; 40: Name = name; 41: Age = age; 42: DateOfBirth = dob; 43: InvoiceNumber = invoiceNumber; 44:  45: Alpha = "QWER"; 46: Beta = 5; 47: Delta = 1.0; 48: Gamma = 0.0; 49: } 50: } In the above example, every constructor over-writes the values for the readonly members. This is perfectly valid. There is a possibility that based on the way the object is instantiated, the readonly member will have a different value. Well, that’s all I have for today and read this as it’s on a related topic.

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• Thoughts on the Nomination Committee Campaign 2014

  - by Testas

  Congratulations to Erin, Andy and Allen on making the Nomination Committee for 2014. As Mark Broadbent (@retracement) stated in his tweet, there’s a great set of individuals for the Nom Com, and I could not agree more. I know Erin and Allen, and I know how much value they will bring to the process. I don’t know Andy as well, but I am sure he will do a great job and I hope I can meet him at PASS soon. The final candidate appointed by the PASS board is Rick Bolesta, who brings a wealth of experience to the process. I also want to take the opportunity to thank all who have voted. Not just for me, but for all the candidates during the election. Your contribution is greatly appreciated. Would I apply for the Nom Com again?  Yes I would. My first election experience has been a learning experience in itself. So I accept the result and look forward to applying next year. Moving on from this, I do want to express my opinion about the lack of international representation in the election process. One of the tweets that I saw after the result was from Adam Machanic (@AdamMachanic) who commented on the lack of international members on the Nom Com. If truth be told, I was disappointed – when the candidate list was released -- that for the second time in recent elections there was a lack of international candidates on the candidate list. It feels that only Brits and Americans partake in such elections. This is a real shame, and I can’t help thinking why this is the case. Hugo Kornelis (@Hugo_Kornelis) wrote a blog here to express his thoughts. He did raise some valid points. I don’t know why there is an absence of international candidates. I know that the team at PASS are looking to improve the situation, so I do not want to give the impression that PASS are doing nothing. For reference please see Bill Graziano’ s article here to see how PASS are addressing the situation. There is a clear direction to change the rules within PASS to give greater inclusion of international members. In addition to this, I wanted to explore a couple of potential approaches to address the situation. I am not saying that they are the right answer, but when I see challenges, I like to bring potential solutions to the table. 1.       Use the PASS mission statement to define a tactical objective that engages community leaders into the election process. If you are not familiar with the PASS mission statement, let me provide it here as laid out on the PASS website. “Empower data professionals who leverage Microsoft technologies to connect, share, and learn through networking, knowledge sharing, and peer-based learning” PASS fulfil this mission statement regularly. Whether you attend SQL Saturday, SQLRally, SQLPASS and BA conference itself. The biggest value of PASS is the ability to bring our profession together. And the 24 hour hop allows you to learn from the comfort of your own office/home. This mission should be extended to define a tactical objectives that bring greater networking and knowledge sharing between PASS Chapter leaders/Regional Mentors and PASS HQ. It should help educate the leaders about the opportunities of elections and how leaders can become involved. I know PASS engage with Chapter leaders on a regular basis to discuss community matters for the benefit of PASS members. How could this be achieved? Perhaps PASS could perform a quarterly virtual meeting that specifically looks at helping leaders become more involved with the election process 2.       Evolve the Global Growth Strategy into a Global Engagement Strategy. One of the remits of the PASS board over the last couple of years is the Global Growth strategy. This has been very successful as we have seen the massive growth of events across the world. For that, I congratulate the board for this success. Perhaps the time is now right to look at solidifying this success, through a Global Engagement Strategy that starts with the collaboration of Chapter Leaders, Regional Mentors and Evangelists in their respective Countries or Regions. The engagement strategy should look at increasing collaboration between community leaders for the benefit of their respective communities. It should also provide a channel for encouraging leaders to put themselves forward for the elections. How could this be achieved? In the UK, there has been a big growth in PASS Chapters and SQL Server Events that was approaching saturation point. The introduction of the Community Engagement Day -- channelled through the SQLBits conference -- has enabled Chapter Leaders to collaborate, connect and share with PASS, Sponsors and Microsoft. It also provides the ability for Chapter Leaders to speak directly to the PASS representatives from PASSHQ. This brings with it the ability for PASS community evangelists to communicate PASS objectives. It has also been the event where we have found out; and/or encouraged, Chapter Leaders to put themselves forward for elections. People like encouragement and validation when going for something like an election, and being able to discuss this with peers at a dedicated event provides a useful platform. PASS has the people in place already to facilitate such an event. Regional Mentors could potentially help organise such events on an annual basis, with PASSHQ providing support in providing a room/Lync access for the event to take place. It would be really good if a PASSHQ representative could attend in person as well.   3.       Restrict candidates to serve only a limited number of terms. A frequent comment I saw on social networking was that the elections can be seen by some as a popularity conference. Perhaps by limiting the number of terms that an individual can serve on either the Nom Com or the BOD, other candidates may be encouraged to be more actively involved within the PASS election process. I don’t think that the current byelaws deal with this particular suggestion. I also saw a couple of tweets that stated that more active community members did not apply for the Nom Com. I struggled to understand how the individuals of the tweets measured “more active”. It just also further solidified the subjective nature of elections. In the absence of how candidates are put forward for the elections. Then a restriction of terms enables the opportunity to be extended to others. How could this be achieved? Set a resolution that is put to a community vote as to the viability of such a solution. For example, the questions for the vote could be: Should individuals in the Nom Com and BoD be limited to a certain number of terms?  Yes/No. What is the maximum number of terms a candidate could serve?   It would be simple to execute such a vote, and the community will have an opportunity to have a say in an important aspect of the PASS organisation. And is the change is successful, then add it as a byelaw.   So there are some of my thoughts. I am not saying they are right or wrong. But I do hope that there is a concerted effort to encourage more candidates from other reaches of the Globe to become involved with future elections.   It would be good to hear your thoughts   Thanks   Chris

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• Checking who is connected to your server, with PowerShell.

  - by Fatherjack

  There are many occasions when, as a DBA, you want to see who is connected to your SQL Server, along with how they are connecting and what sort of activities they are carrying out. I’m going to look at a couple of ways of getting this information and compare the effort required and the results achieved of each. SQL Server comes with a couple of stored procedures to help with this sort of task – sp_who and its undocumented counterpart sp_who2. There is also the pumped up version of these called sp_whoisactive, written by Adam Machanic which does way more than these procedures. I wholly recommend you try it out if you don’t already know how it works. When it comes to serious interrogation of your SQL Server activity then it is absolutely indispensable. Anyway, back to the point of this blog, we are going to look at getting the information from sp_who2 for a remote server. I wrote this Powershell script a week or so ago and was quietly happy with it for a while. I’m relatively new to Powershell so forgive both my rather low threshold for entertainment and the fact that something so simple is a moderate achievement for me. $Server = 'SERVERNAME' $SMOServer = New-Object Microsoft.SQLServer.Management.SMO.Server $Server # connection and query stuff         $ConnectionStr = "Server=$Server;Database=Master;Integrated Security=True" $Query = "EXEC sp_who2" $Connection = new-object system.Data.SQLClient.SQLConnection $Table = new-object "System.Data.DataTable" $Connection.connectionstring = $ConnectionStr try{ $Connection.open() $Command = $Connection.CreateCommand() $Command.commandtext = $Query $result = $Command.ExecuteReader() $Table.Load($result) } catch{ # Show error $error[0] | format-list -Force } $Title = "Data access processes (" + $Table.Rows.Count + ")" $Table | Out-GridView -Title $Title $Connection.close() So this is pretty straightforward, create an SMO object that represents our chosen server, define a connection to the database and a table object for the results when we get them, execute our query over the connection, load the results into our table object and then, if everything is error free display these results to the PowerShell grid viewer. The query simply gets the results of ‘EXEC sp_who2′ for us. Depending on how many connections there are will influence how long the query runs. The grid viewer lets me sort and search the results so it can be a pretty handy way to locate troublesome connections. Like I say, I was quite pleased with this, it seems a pretty simple script and was working well for me, I have added a few parameters to control the output and give me more specific details but then I see a script that uses the $SMOServer object itself to provide the process information and saves having to define the connection object and query specifications. $Server = 'SERVERNAME' $SMOServer = New-Object Microsoft.SQLServer.Management.SMO.Server $Server $Processes = $SMOServer.EnumProcesses() $Title = "SMO processes (" + $Processes.Rows.Count + ")" $Processes | Out-GridView -Title $Title Create the SMO object of our server and then call the EnumProcesses method to get all the process information from the server. Staggeringly simple! The results are a little different though. Some columns are the same and we can see the same basic information so my first thought was to which runs faster – so that I can get my results more quickly and also so that I place less stress on my server(s). PowerShell comes with a great way of testing this – the Measure-Command function. All you have to do is wrap your piece of code in Measure-Command {[your code here]} and it will spit out the time taken to execute the code. So, I placed both of the above methods of getting SQL Server process connections in two Measure-Command wrappers and pressed F5! The Powershell console goes blank for a while as the code is executed internally when Measure-Command is used but the grid viewer windows appear and the console shows this. You can take the output from Measure-Command and format it for easier reading but in a simple comparison like this we can simply cross refer the TotalMilliseconds values from the two result sets to see how the two methods performed. The query execution method (running EXEC sp_who2 ) is the first set of timings and the SMO EnumProcesses is the second. I have run these on a variety of servers and while the results vary from execution to execution I have never seen the SMO version slower than the other. The difference has varied and the time for both has ranged from sub-second as we see above to almost 5 seconds on other systems. This difference, I would suggest is partly due to the cost overhead of having to construct the data connection and so on where as the SMO EnumProcesses method has the connection to the server already in place and just needs to call back the process information. There is also the difference in the data sets to consider. Let’s take a look at what we get and where the two methods differ Query execution method (sp_who2) SMO EnumProcesses Description - Urn What looks like an XML or JSON representation of the server name and the process ID SPID Spid The process ID Status Status The status of the process Login Login The login name of the user executing the command HostName Host The name of the computer where the  process originated BlkBy BlockingSpid The SPID of a process that is blocking this one DBName Database The database that this process is connected to Command Command The type of command that is executing CPUTime Cpu The CPU activity related to this process DiskIO - The Disk IO activity related to this process LastBatch - The time the last batch was executed from this process. ProgramName Program The application that is facilitating the process connection to the SQL Server. SPID1 - In my experience this is always the same value as SPID. REQUESTID - In my experience this is always 0 - Name In my experience this is always the same value as SPID and so could be seen as analogous to SPID1 from sp_who2 - MemUsage An indication of the memory used by this process but I don’t know what it is measured in (bytes, Kb, Mb…) - IsSystem True or False depending on whether the process is internal to the SQL Server instance or has been created by an external connection requesting data. - ExecutionContextID In my experience this is always 0 so could be analogous to REQUESTID from sp_who2. Please note, these are my own very brief descriptions of these columns, detail can be found from MSDN for columns in the sp_who results here http://msdn.microsoft.com/en-GB/library/ms174313.aspx. Where the columns are common then I would use that description, in other cases then the information returned is purely for interpretation by the reader. Rather annoyingly both result sets have useful information that the other doesn’t. sp_who2 returns Disk IO and LastBatch information which is really useful but the SMO processes method give you IsSystem and MemUsage which have their place in fault diagnosis methods too. So which is better? On reflection I think I prefer to use the sp_who2 method primarily but knowing that the SMO Enumprocesses method is there when I need it is really useful and I’m sure I’ll use it regularly. I’m OK with the fact that it is the slower method because Measure-Command has shown me how close it is to the other option and that it really isn’t a large enough margin to matter.

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• Visual Studio 2010 Productivity Tips and Tricks&ndash;Part 1: Extensions

  - by ToStringTheory

  I don’t know about you, but when it comes to development, I prefer my environment to be as free of clutter as possible.  It may surprise you to know that I have tried ReSharper, and did not like it, for the reason that I stated above.  In my opinion, it had too much clutter.  Don’t get me wrong, there were a couple of features that I did like about it (inversion of if blocks, code feedback), but for the most part, I actually felt that it was slowing me down. Introduction Another large factor besides intrusiveness/speed in my choice to dislike ReSharper would probably be that I have become comfortable with my current setup and extensions.  I believe I have a good collection, and am quite happy with what I can accomplish in a short amount of time.  I figured that I would share some of my tips/findings regarding Visual Studio productivity here, and see what you had to say. The first section of things that I would like to cover, are Visual Studio Extensions.  In case you have been living under a rock for the past several years, Extensions are available under the Tools menu in Visual Studio: The extension manager enables integrated access to the Microsoft Visual Studio Gallery online with access to a few thousand different extensions.  I have tried many extensions, but for reasons of lack reliability, usability, or features, have uninstalled almost all of them.  However, I have come across several that I find I can not do without anymore: NuGet Package Manager (Microsoft) Perspectives (Adam Driscoll) Productivity Power Tools (Microsoft) Web Essentials (Mads Kristensen) Extensions NuGet Package Manager To be honest, I debated on whether or not to put this in here.  Most people seem to have it, however, there was a time when I didn’t, and was always confused when blogs/posts would say to right click and “Add Package Reference…” which with one of the latest updates is now “Manage NuGet Packages”.  So, if you haven’t downloaded the NuGet Package Manager yet, or don’t know what it is, I would highly suggest downloading it now! Features Simply put, the NuGet Package Manager gives you a GUI and command line to access different libraries that have been uploaded to NuGet. Some of its features include: Ability to search NuGet for packages via the GUI, with information in the detail bar on the right. Quick access to see what packages are in a solution, and what packages have updates available, with easy 1-click updating. If you download a package that requires references to work on other NuGet packages, they will be downloaded and referenced automatically. Productivity Tip If you use any type of source control in Visual Studio as well as using NuGet packages, be sure to right-click on the solution and click "Enable NuGet Package Restore". What this does is add a NuGet package to the solution so that it will be checked in along side your solution, as well as automatically grab packages from NuGet on build if needed. This is an extremely simple system to use to manage your package references, instead of having to manually go into TFS and add the Packages folder. Perspectives I can't stand developing with just one monitor. Especially if it comes to debugging. The great thing about Visual Studio 2010, is that all of the panels and windows are floatable, and can dock to other screens. The only bad thing is, I don't use the same toolset with everything that I am doing. By this, I mean that I don't use all of the same windows for debugging a web application, as I do for coding a WPF application. Only thing is, Visual Studio doesn't save the screen positions for all of the undocked windows. So, I got curious one day and decided to check and see if there was an extension to help out. This is where I found Perspectives. Features Perspectives gives you the ability to configure window positions across any or your monitors, and then to save the positions in a profile. Perspectives offers a Panel to manage different presets/favorites, and a toolbar to add to the toolbars at the top of Visual Studio. Ability to 'Favorite' a profile to add it to the perspectives toolbar. Productivity Tip Take the time to setup profiles for each of your scenarios - debugging web/winforms/xaml, coding, maintenance, etc. Try to remember to use the profiles for a few days, and at the end of a week, you may find that your productivity was never better. Productivity Power Tools Ah, the Productivity Power Tools... Quite possibly one of my most used extensions, if not my most used. The tool pack gives you a variety of enhancements ranging from key shortcuts, interface tweaks, and completely new features to Visual Studio 2010. Features I don't want to bore you with all of the features here, so here are my favorite: Quick Find - Unobtrusive search box in upper-right corner of the code window. Great for searching in general, especially in a file. Solution Navigator - The 'Solution Explorer' on steroids. Easy to search for files, see defined members/properties/methods in files, and my favorite feature is the 'set as root' option. Updated 'Add Reference...' Dialog - This is probably my favorite enhancement period... The 'Add Reference...' dialog redone in a manner that resembles the Extension/Package managers. I especially love the ability to search through all of the references. "Ctrl - Click" for Definition - I am still getting used to this as I usually try to use my keyboard for everything, but I love the ability to hold Ctrl and turn property/methods/variables into hyperlinks, that you click on to see their definitions. Great for travelling down a rabbit hole in an application to research problems. While there are other commands/utilities, I find these to be the ones that I lean on the most for the usefulness. Web Essentials If you have do any type of web development in ASP .Net, ASP .Net MVC, even HTML, I highly suggest grabbing the Web Essentials right NOW! This extension alone is great for productivity in web development, and greatly decreases my development time on new features. Features Some of its best features include: CSS Previews - I say 'previews' because of the multiple kinds of previews in CSS that you get font-family, color, background/background-image previews. This is great for just tweaking UI slightly in different ways and seeing how they look in the CSS window at a glance. Live Preview - One word - awesome! This goes well with my multi-monitor setup. I put the site on one monitor in a Live Preview panel, and then as I make changes to CSS/cshtml/aspx/html, the preview window will update with each save/build automatically. For CSS, you can even turn on live-update, so as you are tweaking CSS, the style changes in real time. Great for tweaking colors or font-sizes. Outlining - Small, but I like to be able to collapse regions/declarations that are in the way of new work, or are just distracting. Commenting Shortcuts - I don't know why it wasn't included by default, but it is nice to have the key shortcuts for commenting working in the CSS editor as well. Productivity Tip When working on a site, hit CTRL-ALT-ENTER to launch the Live Preview window. Dock it to another monitor. When you make changes to the document/css, just save and glance at the other monitor. No need to alt tab, then alt tab before continuing editing. Conclusion These extensions are only the most useful and least intrusive - ones that I use every day. The great thing about Visual Studio 2010 is the extensibility options that it gives developers to utilize. Have an extension that you use that isn't intrusive, but isn't listed here? Please, feel free to comment. I love trying new things, and am always looking for new additions to my toolset of the most useful. Finally, please keep an eye out for Part 2 on key shortcuts in Visual Studio. Also, if you are visiting my site (http://tostringtheory.com || http://geekswithblogs.net/tostringtheory) from an actual browser and not a feed, please let me know what you think of the new styling!

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• How to diagnose cause, fix, or work around Adobe ActiveX / COM related error 0x80004005 progmaticall

  - by Streamline

  I've built a C# .NET app that uses the Adobe ActiveX control to display a PDF. It relies on a couple DLLs that get shipped with the application. These DLLs interact with the locally installed Adobe Acrobat or Adobe Acrobat Reader installed on the machine. This app is being used by some customer already and works great for nearly all users ( I check to see that the local machine is running at least version 9 of either Acrobat or Reader already ). I've found 3 cases where the app returns the error message "Error HRESULT E_FAIL has been returned from a call to a COM component" when trying to load (when the activex control is loading). I've checked one of these user's machines and he has Acrobat 9 installed and is using it frequently with no problems. It does appear that Acrobat 7 and 8 were installed at one time since there are entries for them in the registry along with Acrobat 9. I can't reproduce this problem locally, so I am not sure exactly which direction to go. The error at the top of the stacktrace is: System.Runtime.InteropServices.COMException (0x80004005): Error HRESULT E_FAIL has been returned from a call to a COM component. Some research into this error indicates it is a registry problem. Does anyone have a clue as to how to fix or work around this problem, or determine how to get to the core root of the problem? The full content of the error message is this: System.Runtime.InteropServices.COMException (0x80004005): Error HRESULT E_FAIL has been returned from a call to a COM component.    at System.Windows.Forms.UnsafeNativeMethods.CoCreateInstance(Guid& clsid, Object punkOuter, Int32 context, Guid& iid)    at System.Windows.Forms.AxHost.CreateWithoutLicense(Guid clsid)    at System.Windows.Forms.AxHost.CreateWithLicense(String license, Guid clsid)    at System.Windows.Forms.AxHost.CreateInstanceCore(Guid clsid)    at System.Windows.Forms.AxHost.CreateInstance()    at System.Windows.Forms.AxHost.GetOcxCreate()    at System.Windows.Forms.AxHost.TransitionUpTo(Int32 state)    at System.Windows.Forms.AxHost.CreateHandle()    at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)    at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)    at System.Windows.Forms.AxHost.EndInit()    at AcrobatChecker.Viewer.InitializeComponent()    at AcrobatChecker.Viewer..ctor()    at AcrobatChecker.Form1.btnViewer_Click(Object sender, EventArgs e)    at System.Windows.Forms.Control.OnClick(EventArgs e)    at System.Windows.Forms.Button.OnClick(EventArgs e)    at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)    at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)    at System.Windows.Forms.Control.WndProc(Message& m)    at System.Windows.Forms.ButtonBase.WndProc(Message& m)    at System.Windows.Forms.Button.WndProc(Message& m)    at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)    at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)    at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

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• Mercurial extensions not working in Windows 7 x64?

  - by Samuel Meacham

  We are test driving Mercurial at work. We don't want to have to enter our user/pass each time we interact with a repository, so we set up the mercurial_keyring extension. We: Installed Python 2.6.5 (32 or 64 bit, depending on the system) Installed setuptools (for easy_install.exe) easy_install keyring easy_install mercurial_keyring And then made the appropriate changes to %userprofile%/mercurial.ini in the [auth] section. It works fine on my colleague's computer (32bit xp sp3), but it does not work on my machine (Windows 7 Ultimate x64). Also noteworthy, the setuptools had to be built from source on Win 7 x64 (python setup.py bdist_wininst, then run the resulting setuptools-0.6c11.win-amd64.exe). Using just hg.exe from the Mercurial 1.5 binary installation (the .msi), I get this error when I run hg.exe: * failed to import extension mercurial_keyring: No module named mercurial_keyring I tried to change my mercurial.ini, to specify the path to the mercurial_keyring.py file, instead of having mercurial find it (since it's in the PYTHONPATH). Old: [extensions] mercurial_keyring = New: [extensions] mercurial_keyring = c:/mercurial/extensions/mercurial_keyring.py The error changes to: abort: could not import module keyring! So while providing the path to the mercurial_keyring extension works, the dependent keyring module still cannot be found. After further investigation, it appears that NO extensions work. They all produce the error: * failed to import extension [extension name]: No module named [module name] It appears that when running hg.exe, it is not aware of PYTHONPATH. I have tried: Python 2.6.5 32 bit Python 2.6.5 64 bit Building Mercurial 1.5 from source with MinGW Building Mercurial 1.5 from source with MSVC9 Using hg.exe from the 1.5 binary dist (.msi) Using the hg.py in c:\python26\scripts when building from source Various configurations in %userprofile%/mercurial.ini Using setuptools (easy_install.exe) to install keyring and mercurial_keyring Building keyring and mercurial_keyring from source (python setup.py bdist_wininst) Nothing works. The closest I've got is using hg.py when building from source. It at least doesn't give me errors, and actually creates %userprofile%/wincrypto_pass.cfg when I enter my credentials. But on subsequent requests, it doesn't enter the credentials automatically. It prompts me for them again. Interestingly, TortoiseHG is using the keyring. I just can't get it to work on the command line. I think something is going on with Win 7 x64 that is preventing mercurial (hg.exe) from seeing the PYTHONPATH, so it can't find any of the installed modules. Does anyone have extensions working in Win 7 x64? Specifically with the binary installation of mercurial (not hg.py)?

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• Does COM interop respect .NET AppDomain boundaries for assembly loading?

  - by Xiaofu

  Here's the core problem: I have a .NET application that is using COM interop in a separate AppDomain. The COM stuff seems to be loading assemblies back into the default domain, rather than the AppDomain from which the COM stuff is being called. What I want to know is: is this expected behaviour, or am I doing something wrong to cause these COM related assemblies to be loaded in the wrong AppDomain? Please see a more detailed description of the situation below... The application consists of 3 assemblies: - the main EXE, the entry point of the application. - common.dll, containing just an interface IController (in the IPlugin style) - controller.dll, containing a Controller class that implements IController and MarshalByRefObject. This class does all the work and uses COM interop to interact with another application. The relevant part of the main EXE looks like this: AppDomain controller_domain = AppDomain.CreateDomain("Controller Domain"); IController c = (IController)controller_domain.CreateInstanceFromAndUnwrap("controller.dll", "MyNamespace.Controller"); result = c.Run(); AppDomain.Unload(controller_domain); The common.dll only contains these 2 things: public enum ControllerRunResult{FatalError, Finished, NonFatalError, NotRun} public interface IController { ControllerRunResult Run(); } And the controller.dll contains this class (which also calls the COM interop stuff): public class Controller: IController, MarshalByRefObject When first running the application, Assembly.GetAssemblies() looks as expected, with common.dll being loaded in both AppDomains, and controller.dll only being loaded into the controller domain. After calling c.Run() however I see that assemblies related to the COM interop stuff have been loaded into the default AppDomain, and NOT in the AppDomain from which the COM interop is taking place. Why might this be occurring? And if you're interested, here's a bit of background: Originally this was a 1 AppDomain application. The COM stuff it interfaces with is a server API which is not stable over long periods of use. When a COMException (with no useful diagnostic information as to its cause) occurs from the COM stuff, the entire application has to restarted before the COM connection will work again. Simply reconnecting to the COM app server results in immediate COM exceptions again. To cope with this I have tried to move the COM interop stuff into a seperate AppDomain so that when the mystery COMExceptions occur I can unload the AppDomain in which it occurs, create a new one and start again, all without having to manually restart the application. That was the theory anyway...

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• Pass or Get a value from Parent ViewModel down to Sub-ViewModel?

  - by mkmurray

  I am using the MVVM Light framework as well as Unity for DI. I have some nested Views, each bound to a corresponding ViewModel. The ViewModels are bound to each View's root control DataContext via the ViewModelLocator idea that Laurent Bugnion has put into MVVM Light. This allows for finding ViewModels via a static resource and for controlling the lifetime of ViewModels via a Dependency Injection framework, in this case Unity. It also allows for Expression Blend to see everything in regard to ViewModels and how to bind them. As I stated the Views have a healthy dose of nesting, but the ViewModels don't really know anything about each other. A parent view binds to its corresponding ViewModel via the static resource ViewModelLocator (which uses Unity to control the construction and lifetime of the ViewModel object). That parent view contains a user control in it that is another sub-view, which then goes and gets its corresponding ViewModel via the ViewModelLocator as well. The ViewModels don't have references to each other or know any hierarchy in regard to each other. So here's an example of how the ViewModels do interact via messaging. I've got a parent View that has a ComboBox databound to an ObservableCollection in its ViewModel. The ComboBox's SelectedItem is also bound (two-way) to a property on the ViewModel. When the selection of the ComboBox changes, this is to trigger updates in other Views and sub-Views. Currently I am accomplishing this via the Messaging system that is found in MVVM Light. So I'm wondering what the best practice would be to get information from one ViewModel to another? In this case, what I need to pass down to sub-ViewModels is basically a user Guid representing the currently logged in user. The top-most parent View (well, ViewModel) will know this information, but I'm not sure how to get it down into the sub-ViewModels. Some possible approaches I can think of: Should the sub-ViewModel ask the static resource ViewModelLocator for a reference to the same object the parent View is using and access the property that way? It seems like ViewModels going through each other's properties is not very clean and couples them together unnecessarily. I'm already using messaging to notify the sub-Views that the user selected a new item in the ComboBox and to update accordingly. But the object type that is being selected in the ComboBox is not really directly related to this data value that the sub-Views need.

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• What Is The Best Database For Delphi Desktop Applications That Supports Stored Procedures?

  - by Cape Cod Gunny

  I started with Turbo Pascal 3, went to TP5, Bought TP6 called Borland the next day and downgraded to TP5.5. Bought Delphi 3, and now have Delphi 5 Enterprise. I sort of lost interest in writing code about 4-5 years ago for two reasons; Spent all day writing ASP & SQL for someone else. PC Techniques magazine went away. I've got a few programs in the shareware market that are solid performers but are in need of serious updating. I love Delphi or did when it was Borland (before Borland bought DBase and all the other crap), I'd like to salvage as much of my D5E code as possible but I doubt I can. I plan on upgrading to Delphi 2010. My next software release needs to interact with a database. I'm very proficient with MS Sql and like to put all of the database code in stored procedures. What is the best database choice that interacts well with Delphi, allows stored procedures and is so easy to deploy that even the Geico gecko could deploy it? 10/25/2009 18:53 PM EST Re-Opened After Reading Install Docs for Delphi 2010 I downloaded a trial version of Delphi 2010 and unzipped the install. I've been reading the install docs included in the package. I started with the install.htm inside the zip package. install.htm wisely tells you to see the following two articles: Installation Notes: http://edn.embarcadero.com/article/39754 Release Notes: http://edn.embarcadero.com/article/39758 the release notes state the following... MSSQL driver requires the installation of the SQL Native Client. SQL Native Client 2008 is required for dbxmss.dll. SQL Native Client 2005 is required for dbxmss9.dll I checked my machine to see if SQL Native Client is installed. Nope. I wasn't done reading the docs so I made a note to install SQL Native Client. I googled dbxmss.dll and dbxmss9.dll and found a very interesting thread on the Embarcadero forums. read thread here. After reading this thread and some careful thought I don't think I will be using Microsoft SQL Express. I can't rely on my customers having the right drivers installed. So, I'm back to looking for a different solution. If I'm selling a $40 product to the general masses I need to have a bulletproof solution that doesn't require my brand new customer to update their machine before my software will work.

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• Tridion Installation

  - by Kevin Brydon

  I am currently upgrading an installation of Tridion from 5.3 to 2011 starting almost from scratch (aside from migrating the database), brand new virtual servers. I just want to ask for some advice on my current server setup... a sanity check. All servers are running Windows Server 2008. The pages on our website are all classic ASP. Database SQL Server cluster. The 5.3 database has been migrated using the DatabaseManager. This is pretty standard and works well (in test anyway). Content Manager A single server to run the Content Manager and the Publisher. There are around 10 people using it at any one time so not under a particularly heavy load. Content Data Store Filesystem located somewhere on the network. One directory for live and one for staging. Content Delivery Two servers (cd1 and cd2) each with the the following server roles installed. cd1 writes to a filesystem content data store for the live website, cd2 writes to the content data store for the staging website. Presentation Two public facing web servers (web1 and web2) serving both the live and staging websites. The web servers read directly from the content data store as its a filesystem. Each of the web servers have the Content Delivery Server installed so that I can use dynamic linking (and other features?). I've so far set up everything but the web servers. Any thoughts? edit Thanks to Ram S who linked me to a decent walkthrough, upvoted. I suppose I should have posed some questions as I didn't really ask a question. I guess I'm a little confused over the content deliver aspect. I have the Content Delivery split in two separate parts. cd1 and cd2 do the work of shifting information from the Content Manager to the Staging/Live web directories. web1 and web2 should do the work of serving the web pages to the outside world and will interact with the content data store (file system). Is this a correct setup? I need some parts of the Content Delivery on my web servers right? Theoretically I could get rid of the cd1 and cd2 servers and use web1 and web2 to do the deployment right? But I suspect this will put the web servers under unnecessary strain should there ever be a big publish. I've been reading the 2011 Installation Manual, Content Delivery section, and I'm finding it quite hard to get my head around!

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• Optimized .htaccess???

  - by StackOverflowNewbie

  I'd appreciate some feedback on the compression and caching configuration below. Trying to come up with a general purpose, optimized compression and caching configuration. If possible: Note your PageSpeed and YSlow grades Add configuration to your .htaccess Clear your cache Note your PageSpeed and YSlow grades to see if there are any improvements (or degradations) NOTE: Make sure you have appropriate modules loaded. Any feedback is much appreciated. Thanks. # JavaScript MIME type issues: # 1. Apache uses "application/javascript": http://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x/conf/mime.types # 2. IIS uses "application/x-javascript": http://technet.microsoft.com/en-us/library/bb742440.aspx # 3. SVG specification says it is text/ecmascript: http://www.w3.org/TR/2001/REC-SVG-20010904/script.html#ScriptElement # 4. HTML specification says it is text/javascript: http://www.w3.org/TR/1999/REC-html401-19991224/interact/scripts.html#h-18.2.2.2 # 5. "text/ecmascript" and "text/javascript" are considered obsolete: http://www.rfc-editor.org/rfc/rfc4329.txt #------------------------------------------------------------------------------- # Compression #------------------------------------------------------------------------------- <IfModule mod_deflate.c> AddOutputFilterByType DEFLATE application/xhtml+xml AddOutputFilterByType DEFLATE application/xml AddOutputFilterByType DEFLATE application/atom+xml AddOutputFilterByType DEFLATE text/css AddOutputFilterByType DEFLATE text/html AddOutputFilterByType DEFLATE text/plain AddOutputFilterByType DEFLATE text/xml # The following MIME types are in the process of registration AddOutputFilterByType DEFLATE application/xslt+xml AddOutputFilterByType DEFLATE image/svg+xml # The following MIME types are NOT registered AddOutputFilterByType DEFLATE application/mathml+xml AddOutputFilterByType DEFLATE application/rss+xml # Deal with JavaScript MIME type issues AddOutputFilterByType DEFLATE application/javascript AddOutputFilterByType DEFLATE application/x-javascript AddOutputFilterByType DEFLATE text/ecmascript AddOutputFilterByType DEFLATE text/javascript </IfModule> #------------------------------------------------------------------------------- # Expires header #------------------------------------------------------------------------------- <IfModule mod_expires.c> # 1. Set Expires to a minimum of 1 month, and preferably up to 1 year, in the future # (but not more than 1 year as that would violate the RFC guidelines) # 2. Use "Expires" over "Cache-Control: max-age" because it is more widely accepted ExpiresActive on ExpiresByType application/pdf "access plus 1 year" ExpiresByType application/x-shockwave-flash "access plus 1 year" ExpiresByType image/bmp "access plus 1 year" ExpiresByType image/gif "access plus 1 year" ExpiresByType image/jpeg "access plus 1 year" ExpiresByType image/png "access plus 1 year" ExpiresByType image/svg+xml "access plus 1 year" ExpiresByType image/tiff "access plus 1 year" ExpiresByType image/x-icon "access plus 1 year" ExpiresByType text/css "access plus 1 year" ExpiresByType video/x-flv "access plus 1 year" # Deal with JavaScript MIME type issues ExpiresByType application/javascript "access plus 1 year" ExpiresByType application/x-javascript "access plus 1 year" ExpiresByType text/ecmascript "access plus 1 year" ExpiresByType text/javascript "access plus 1 year" # Probably better to explicitly declare MIME types than to have a blanket rule for expiration # Uncomment below if you disagree #ExpiresDefault "access plus 1 year" </IfModule> #------------------------------------------------------------------------------- # Caching #------------------------------------------------------------------------------- <IfModule mod_headers.c> <FilesMatch "\.(bmp|css|flv|gif|ico|jpg|jpeg|js|pdf|png|svg|swf|tif|tiff)$"> Header add Cache-Control "public" Header unset ETag Header unset Last-Modified FileETag none </FilesMatch> </IfModule>

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• EJB3 Transaction Propogation

  - by Matt S.

  I have a stateless bean something like: @Stateless public class MyStatelessBean implements MyStatelessLocal, MyStatelessRemote { @PersistenceContext(unitName="myPC") private EntityManager mgr; @TransationAttribute(TransactionAttributeType.SUPPORTED) public void processObjects(List<Object> objs) { // this method just processes the data; no need for a transaction for(Object obj : objs) { this.process(obj); } } @TransationAttribute(TransactionAttributeType.REQUIRES_NEW) public void process(Object obj) { // do some work with obj that must be in the scope of a transaction this.mgr.merge(obj); // ... this.mgr.merge(obj); // ... this.mgr.flush(); } } The typically usage then is the client would call processObjects(...), which doesn't actually interact with the entity manager. It does what it needs to do and calls process(...) individually for each object to process. The duration of process(...) is relatively short, but processObjects(...) could take a very long time to run through everything. Therefore I don't want it to maintain an open transaction. I do need the individual process(...) operations to operate within their own transaction. This should be a new transaction for every call. Lastly I'd like to keep the option open for the client to call process(...) directly. I've tried a number of different transaction types: never, not supported, supported (on processObjects) and required, requires new (on process) but I get TransactionRequiredException every time merge() is called. I've been able to make it work by splitting up the methods into two different beans: @Stateless @TransationAttribute(TransactionAttributeType.NOT_SUPPORTED) public class MyStatelessBean1 implements MyStatelessLocal1, MyStatelessRemote1 { @EJB private MyStatelessBean2 myBean2; public void processObjects(List<Object> objs) { // this method just processes the data; no need for a transaction for(Object obj : objs) { this.myBean2.process(obj); } } } @Stateless public class MyStatelessBean2 implements MyStatelessLocal2, MyStatelessRemote2 { @PersistenceContext(unitName="myPC") private EntityManager mgr; @TransationAttribute(TransactionAttributeType.REQUIRES_NEW) public void process(Object obj) { // do some work with obj that must be in the scope of a transaction this.mgr.merge(obj); // ... this.mgr.merge(obj); // ... this.mgr.flush(); } } but I'm still curious if it's possible to accomplish this in one class. It looks to me like the transaction manager only operates at the bean level, even when individual methods are given more specific annotations. So if I mark one method in a way to prevent the transaction from starting calling other methods within that same instance will also not create a transaction, no matter how they're marked? I'm using JBoss Application Server 4.2.1.GA, but non-specific answers are welcome / preferred.

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• Design question for WinForms (C#) app, using Entity Framework

  - by cdotlister

  I am planning on writing a small home budget application for myself, as a learning excercise. I have built my database (SQL Server), and written a small console application to interact with it, and test out scenarios on my database. Once I am happy, my next step would be to start building the application - but I am already wondering what the best/standard design would be. I am palnning on using Entity Framework for handling my database entities... then linq to sql/objects for getting the data, all running under a WinForms (for now) application. My plan (I've never used EF... and most of my development background is Web apps) is to have my database... with Entity Framework in it's own project.. which has the connection to the database. This project would expose methods such as 'GetAccount()', 'GetAccount(int accountId)' etc. I'd then have a service project that references my EF project. And on top of that, my GUI project, which makes the calls to my service project. But I am stuck. Lets say I have a screen that displays a list of Account types (Debit, Credit, Loan...). Once I have selected one, the next drop down shows a list of accounts I have that suite that account type. So, my OnChange event on my DropDown on the account type control will make a call to the serviceLayer project, 'GetAccountTypes()', and I would expect back a List< of Account Types. However, the AccountType object ... what is that? That can't be the AccountType object from my EF project, as my GUI project doesn't have reference to it. Would I have to have some sort of Shared Library, shared between my GUI and my Service project, with a custom built AccountType object? The GUI can then expect back a list of these. So my service layer would have a method: public List<AccountType> GetAccountTypes() That would then make a call to a custom method in my EF project, which would probably be the same as the above method, except, it returns an list of EF.Data.AccountType (The Entity Framework generated Account Type object). The method would then have the linq code to get the data as I want it. Then my service layer will get that object, and transform it unto my custom AccountType object, and return it to the GUI. Does that sound at all like a good plan?

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• .NET SerialPort DataReceived event thread interference with main thread

  - by Kiran

  I am writing a serial communication program using the SerialPort class in C# to interact with a strip machine connected via a RS232 cable. When i send the command to the machine it responds with some bytes depending on the command. Like when i send a "\D" command, i am expecting to download the machine program data of 180 bytes as a continous string. As per the machine's manual, it suggests as a best practice to send an unreognized characters like comma (,) character to make sure the machine is initialized before sending the first command in the cycle. My serial communication code is as follows: public class SerialHelper { SerialPort commPort = null; string currentReceived = string.Empty; string receivedStr = string.Empty; private bool CommInitialized() { try { commPort = new SerialPort(); commPort.PortName = "COM1"; if (!commPort.IsOpen) commPort.Open(); commPort.BaudRate = 9600; commPort.Parity = System.IO.Ports.Parity.None; commPort.StopBits = StopBits.One; commPort.DataBits = 8; commPort.RtsEnable = true; commPort.DtrEnable = true; commPort.DataReceived += new SerialDataReceivedEventHandler(commPort_DataReceived); return true; } catch (Exception ex) { return false; } } void commPort_DataReceived(object sender, SerialDataReceivedEventArgs e) { SerialPort currentPort = (SerialPort)sender; currentReceived = currentPort.ReadExisting(); receivedStr += currentReceived; } internal int CommIO(string outString, int outLen, ref string inBuffer, int inLen) { receivedStr = string.Empty; inBuffer = string.Empty; if (CommInitialized()) { commPort.Write(outString); } System.Threading.Thread.Sleep(1500); int i = 0; while ((receivedStr.Length < inLen) && i < 10) { System.Threading.Thread.Sleep(500); i += 1; } if (!string.IsNullOrEmpty(receivedStr)) { inBuffer = receivedStr; } commPort.Close(); return inBuffer.Length; } } I am calling this code from a windows form as follows: len = SerialHelperObj.CommIO(",",1,ref inBuffer, 4) len = SerialHelperObj.CommIO(",",1,ref inBuffer, 4) If(inBuffer == "!?*O") { len = SerialHelperObj.CommIO("\D",2,ref inBuffer, 180) } A valid return value from the serial port looks like this: \D00000010000000000010 550 3250 0000256000 and so on ... I am getting some thing like this: \D00000010D,, 000 550 D,, and so on... I feel that my comm calls are getting interferred with the one when i send commands. But i am trying to make sure the result of the comma command then initiating the actual command. but the received thread is inserting the bytes from the previous communication cycle. Can any one please shed some light into this...? I lost quite some hair just trying to get this work. I am not sure where i am doing wrong

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• How can I troubleshoot an APPCRASH in Internet Explorer?

  - by Schnapple

  I'm writing an ActiveX control using the firebreath framework (hi taxilian!) and while it technically works, I'm running into a weird issue that appears to be unique to me. I've followed the instructions to create a simple plugin and then I ran it in Internet Explorer 8 on Windows 7 x64 (firebreath sets up a test page for the control). But as soon as I try to test it (clicking on a link that fires off JavaScript to interact with the control), IE crashes. Hard. "Internet Explorer has stopped working" style. If I try the control in Firefox (the resulting registered DLL can also be called as a Firefox plugin using a MIME type), it works fine. If I try it on my XP box, it works fine. I emailed the DLL and the testing page to a coworker in the next cube who is like me also running Windows 7 x64 and it works for him just fine as well, so it's not something unique to Windows 7 or x64. When it crashes I get this message: Problem signature: Problem Event Name: APPCRASH Application Name: iexplore.exe Application Version: 8.0.7600.16385 Application Timestamp: 4a5bc69e Fault Module Name: RPCRT4.dll Fault Module Version: 6.1.7600.16385 Fault Module Timestamp: 4a5bdb3b Exception Code: c0000005 Exception Offset: 000220b1 OS Version: 6.1.7600.2.0.0.256.1 Locale ID: 1033 Additional Information 1: 0a9e Additional Information 2: 0a9e372d3b4ad19135b953a78882e789 Additional Information 3: 0a9e Additional Information 4: 0a9e372d3b4ad19135b953a78882e789 Which tells me nothing extremely useful. I can have it attach to a debugger but it just tells me a long list of DLL's, none of which are the ActiveX control in question. It's almost like it's not even getting there. I did a sfc /scannow yesterday to see if anything on my system is corrupt and nothing came up as wrong. I tried various different security levels in IE, but nothing seems to have any effect. As this is a development machine there has been all matter of crap installed on it, so I figure it's bound to be something I've installed since October (when Win7 was released) but I cannot figure out what it is. I presume the information it's giving me when I attach to Visual Studio is useful somehow but I don't know how to interpret it. Admittedly I'm mainly a C#/.NET developer who's a bit out of his element with C/C++ and troubleshooting native code, but does anyone have any advice on how to proceed on figuring out why this very simple ActiveX control crashes IE on my machine and nowhere else?

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• How do you attract programmers in rural areas?

  - by Reed Copsey

  I run a software development group for a very small, but stable and established company in a small town, somewhat outside of the "big city". Unfortunately, the "programmer" labor pool is much smaller due to the size of the city. There are many positives to working in this area, especially in terms of quality of life (particularly for people interested in outdoor activities), lower cost of living, great schools and neighborhoods, etc. However, I've always had difficulty attracting high-qualtiy, experienced developers. For those of you who hire developers outside of large cities: Where do you advertise to find good developers? Many of the large sites are very focused in certain metropolitan areas, and seem inappropriate places to advertise if you're outside of that main region. How do you attract quality developers to rural (or at least less metropolitan) locations? Do you find that you make more sacrifices in your hiring due to a smaller labor pool? Or do you just wait, and take extra time to attract people? What sacrifices do you expect to make if you are outside of the main developer-rich cities? For all of the developers out there... What would entice you to working in a smaller town? Are there things that would stand out and make you willing to relocate or at least apply to a position that was not nearby? What specific qualities would help you want to move outside of the city? In the past, I've had difficulty with finding good people. Most of the people who've applied and been willing to move out to a more rural location seem like the types that can't keep a quality job elsewhere. I'd like to know what advice people have to attracting quality technical staff. I don't believe its the work itself that's been the problem - The work is both interesting and challenging, and nearly 100% new development. The developers I have seem very happy with their situation - they love the work, the atmosphere, etc. It's more a matter of finding willing, able developers. Edit: More info after the first couple of answers: Right now, some of my best developers telecommute (some work from overseas); however, for this question, I'm trying to figure out how to get people who want to live and work full time locally. I need some people with whom I interact every day.

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• How can I use functools.partial on multiple methods on an object, and freeze parameters out of order

  - by Joseph Garvin

  I find functools.partial to be extremely useful, but I would like to be able to freeze arguments out of order (the argument you want to freeze is not always the first one) and I'd like to be able to apply it to several methods on a class at once, to make a proxy object that has the same methods as the underlying object except with some of its methods parameter being frozen (think of it as generalizing partial to apply to classes). I've managed to scrap together a version of functools.partial called 'bind' that lets me specify parameters out of order by passing them by keyword argument. That part works: >>> def foo(x, y): ... print x, y ... >>> bar = bind(foo, y=3) >>> bar(2) 2 3 But my proxy class does not work, and I'm not sure why: >>> class Foo(object): ... def bar(self, x, y): ... print x, y ... >>> a = Foo() >>> b = PureProxy(a, bar=bind(Foo.bar, y=3)) >>> b.bar(2) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: bar() takes exactly 3 arguments (2 given) I'm probably doing this all sorts of wrong because I'm just going by what I've pieced together from random documentation, blogs, and running dir() on all the pieces. Suggestions both on how to make this work and better ways to implement it would be appreciated ;) One detail I'm unsure about is how this should all interact with descriptors. Code follows. from types import MethodType class PureProxy(object): def __init__(self, underlying, **substitutions): self.underlying = underlying for name in substitutions: subst_attr = substitutions[name] if hasattr(subst_attr, "underlying"): setattr(self, name, MethodType(subst_attr, self, PureProxy)) def __getattribute__(self, name): return getattr(object.__getattribute__(self, "underlying"), name) def bind(f, *args, **kwargs): """ Lets you freeze arguments of a function be certain values. Unlike functools.partial, you can freeze arguments by name, which has the bonus of letting you freeze them out of order. args will be treated just like partial, but kwargs will properly take into account if you are specifying a regular argument by name. """ argspec = inspect.getargspec(f) argdict = copy(kwargs) if hasattr(f, "im_func"): f = f.im_func args_idx = 0 for arg in argspec.args: if args_idx >= len(args): break argdict[arg] = args[args_idx] args_idx += 1 num_plugged = args_idx def new_func(*inner_args, **inner_kwargs): args_idx = 0 for arg in argspec.args[num_plugged:]: if arg in argdict: continue if args_idx >= len(inner_args): # We can't raise an error here because some remaining arguments # may have been passed in by keyword. break argdict[arg] = inner_args[args_idx] args_idx += 1 f(**dict(argdict, **inner_kwargs)) new_func.underlying = f return new_func

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• DriverManager always returns my custom driver regardless of the connection URL

  - by JGB146

  I am writing a driver to act as a wrapper around two separate MySQL connections (to distributed databases). Basically, the goal is to enable interaction with my driver for all applications instead of requiring the application to sort out which database holds the desired data. Most of the code for this is in place, but I'm having a problem in that when I attempt to create connections via the MySQL Driver, the DriverManager is returning an instance of my driver instead of the MySQL Driver. I'd appreciate any tips on what could be causing this and what could be done to fix it! Below is a few relevant snippets of code. I can provide more, but there's a lot, so I'd need to know what else you want to see. First, from MyDriver.java: public MyDriver() throws SQLException { DriverManager.registerDriver(this); } public Connection connect(String url, Properties info) throws SQLException { try { return new MyConnection(info); } catch (Exception e) { return null; } } public boolean acceptsURL(String url) throws SQLException { if (url.contains("jdbc:jgb://")) { return true; } return false; } It is my understanding that this acceptsURL function will dictate whether or not the DriverManager deems my driver a suitable fit for a given URL. Hence it should only be passing connections from my driver if the URL contains "jdbc:jgb://" right? Here's code from MyConnection.java: Connection c1 = null; Connection c2 = null; /** *Constructors */ public DDBSConnection (Properties info) throws SQLException, Exception { info.list(System.out); //included for testing Class.forName("com.mysql.jdbc.Driver").newInstance(); String url1 = "jdbc:mysql://server1.com/jgb"; String url2 = "jdbc:mysql://server2.com/jgb"; this.c1 = DriverManager.getConnection( url1, info.getProperty("username"), info.getProperty("password")); this.c2 = DriverManager.getConnection( url2, info.getProperty("username"), info.getProperty("password")); } And this tells me two things. First, the info.list() call confirms that the correct user and password are being sent. Second, because we enter an infinite loop, we see that the DriverManager is providing new instances of my connection as matches for the mysql URLs instead of the desired mysql driver/connection. FWIW, I have separately tested implementations that go straight to the mysql driver using this exact syntax (al beit only one at a time), and was able to successfully interact with each database individually from a test application outside of my driver.

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• Content Box is a Little Off in IE9 ... How to Fix?

  - by Kelsey Nealon

  Hi there! I have a website at www.thetotempole.ca and when viewed in IE9... My websites content box (The green wooden backgrounded box with content inside) is moved slightly over to the left making a space between the actual container and the content box... Is there anyway I can fix this without harming any of the other browsers? Thanks! Screenshot: HTML: <!DOCTYPE html> <head> <title>The Totem Pole News - Movies</title> <!-- Start WOWSlider.com HEAD section --> <link rel="stylesheet" type="text/css" href="engine1/style.css" /> <script type="text/javascript" src="engine1/jquery.js"></script> <!-- End WOWSlider.com HEAD section --> <script type="text/javascript"> var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-45342007-1']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); </script> <meta charset="utf-8"> <meta name="description" content="A totem pole themed news website posting articles on news, music, movies, video games, and health."> <link href="thecss2.css" rel="stylesheet" type="text/css"> <link rel="icon" type="image/ico" href="images/favicon.ico"> <meta http-equiv="X-UA-Compatible" content="IE=8" /> </head> <body> <div id="container"> <div id="contentbox" align="Center"> <a href="index.html"><div id="banner" align="Center"> </div></a> <div id="navbar"> <p><a href="index.html"><img src="images/home.png" width="65" height="54" alt="picture of a house to relate to the home page (content)" style="position: absolute; left: 23px; top: 16px; width: 57px; height: 48px;"><span style="position: absolute; left: 24px; z-index:2; top: 71px; height: 23px;">Content</span></a> <a href="#"><img src="images/eagleicon.gif" width="73" height="39" alt="An Eagle icon for the News section of the Totem Pole" style="position: absolute; left: 111px; top: 28px;"><span style="position: absolute; z-index: 2; left: 127px; top: 72px;">News</span></a> <a href="#"><img src="images/owlicon.gif" width="81" height="61" alt="An Owl icon for the Music section of the totem pole" style="position: absolute; left: 210px; top: 11px;"><span style="position: absolute; z-index:2; left: 226px; top: 73px;"><strong>Music</strong></span></a><a href="movies.html"><img src="images/wolficon.gif" width="88" height="54" alt="A Wolf icon for the Movies section of the totem pole" style="position: absolute; left: 320px; top: 15px;"><span style="position: absolute; left: 336px; top: 72px; z-index:2;"><strong>Movies</strong></span></a> <a href="#"><img src="images/hareimage.gif" width="60" height="56" alt="A Hare icon for Video Game section of the Totem Pole" style="position: absolute; left: 441px; top: 13px;"><span style="position: absolute; z-index:2; left: 428px; top: 73px;"><strong>Video Games</strong></span></a> <a href="#"><img src="images/bearicon.gif" width="91" height="57" alt="A bear icon for the Health section of The Totem Pole" style="position: absolute; left: 551px; top: 13px;"><span style="position: absolute; left: 580px; top: 72px; z-index:2;">Health</span></a></p> </div> <!--Nav Bar 2--> <div id="navbar2"> <a href="#">About Us</a> <a href="#">Feedback</a> <a href="#">Subscribe</a> </div> <!-- Atomz HTML for Search --> <div id="searchbar"> <form method="get" action="http://search.atomz.com/search/"> <input id="searchbox" size="13" name="sp_q" value="Search..." onFocus="if (this.value == 'Search...') {this.value=''}"> <input class="css_btn_class" type="submit" value="Search"> <input type="hidden" name="sp_a" value="sp1005092e"> <input type="hidden" name="sp_p" value="all"> <input type="hidden" name="sp_f" value="UTF-8"> </form> </div> <!-- Start WOWSlider.com BODY section --> <div id="mywowslider"> <div id="wowslider-container1"> <div class="ws_images"> <ul> <li><img src="images/anchor.jpg" alt="Ron Burgundy" title="Ron Burgundy" id="wows1_0"/>Played by Will Ferrell</li> <li><img src="images/anchor2.jpg" alt="Brian Fantana" title="Brian Fantana" id="wows1_1"/>Played by Paul Rudd</li> <li><img src="images/anchor3.jpg" alt="Brick Tamland" title="Brick Tamland" id="wows1_2"/>Played by Steve Carrell</li> <li><img src="images/anchor4.jpg" alt="Champ Kind" title="Champ Kind" id="wows1_3"/>Played by David Koechner</li> </ul> </div> <div class="ws_bullets"><div> <a href="#" title="Ron Burgundy"><img src="images/anchor.jpg" alt="Ron Burgundy"/>1</a> <a href="#" title="Brian Fantana"><img src="images/anchor2.jpg" alt="Brian Fantana"/>2</a> <a href="#" title="Brick Tamland"><img src="images/anchor3.jpg" alt="Brick Tamland"/>3</a> <a href="#" title="Champ Kind"><img src="images/anchor4.jpg" alt="Champ Kind"/>4</a> </div> </div> <span class="wsl"><a href="http://wowslider.com"></a></span> <div class="ws_shadow"></div> </div> <script type="text/javascript" src="engine1/wowslider.js"></script> <script type="text/javascript" src="engine1/script.js"></script> </div> <!-- End WOWSlider.com BODY section --> <!-- AddThis Smart Layers BEGIN --> <!-- Go to http://www.addthis.com/get/smart-layers to customize --> <script type="text/javascript" src="//s7.addthis.com/js/300/addthis_widget.js#pubid=ra-5279b96309e7df24"></script> <script type="text/javascript"> addthis.layers({ 'theme' : 'transparent', 'share' : { 'position' : 'left', 'numPreferredServices' : 5 } }); </script> <!-- AddThis Smart Layers END --> <div id="sources"><p> Source(s): <a href="http://en.wikipedia.org/wiki/Anchorman_2:_The_Legend_Continues">wikipedia.com</a></p></div> <div id="infocontent"> <p align="left"><em><strong> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Anchorman 2: The Legend Continues</strong></em> is an upcoming American comedy film being released on December 20, 2013, also a sequel to the 2004 film <em>Anchorman: The Legend of Ron Burgandy</em>. On March 28, 2012, actor Will Ferrell officially announced the sequel dressed in character as Ron Burgundy on the late-night talk-show <em>Conan</em>. As with the original film, it is directed by Adam McKay, produced by Judd Apatow, stars Will Ferrell and is written by Adam McKay and Will Ferrell. Unlike the original film, which was distributed by DreamWorks Pictures, <em>The Legend Continues</em> will be distributed by Paramount Pictures.</p> <p align="left"><em><strong>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</strong></em>The movie now has a website at <a href="www.anchormanmovie.com">www.anchormanmovie.com</a> where a countdown for the release of this film can be seen. By the looks of these images, I think we can expect big things when the movie comes out this December. Enjoy the poster photos and trailers all posted below, and don't forget to submit your vote in the poll!</p> </div> <div id="trailer1"><iframe width="560" height="315" src="//www.youtube.com/embed/Elczv0ghqw0?rel=0" frameborder="0" allowfullscreen></iframe></div> <div id="trailer2"> <iframe width="560" height="315" src="//www.youtube.com/embed/mZ-JX-7B3uM?rel=0" frameborder="0" allowfullscreen></iframe> </div> <div id="poll"> <form method="post" action="http://poll.pollcode.com/763294"><table style="border: black 1px solid;" border="1" width="175" bgcolor="EEEEEE" cellspacing="2" cellpadding="0"><tr><td colspan="2" height="10"><font face="Verdana" size="2" color="000000"><b>What Rating Do You Think This Will Recieve</b></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="1" id="763294answer1"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer1">10</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="2" id="763294answer2"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer2">9</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="3" id="763294answer3"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer3">8</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="4" id="763294answer4"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer4">7</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="5" id="763294answer5"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer5">6</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="6" id="763294answer6"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer6">5</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="7" id="763294answer7"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer7">4</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="8" id="763294answer8"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer8">3</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="9" id="763294answer9"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer9">2</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="10" id="763294answer10"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer10">1</label></font></td></tr><tr><td colspan="2" height="10"><center><input type="submit" value=" Vote ">&nbsp;&nbsp;<input title="Clicking this will send you to a new page" type="submit" name="view" value=" View "></center></td></tr><tr><td colspan="2" align="right"><font face="Verdana" height="5" size="1" color="000000"></font></td></tr></table></form></div> <span style="position: absolute; left: 0px; top: 225px; width: 1000px; border-bottom: 2px black double; height: 58px;"> <h1 style="font-weight: normal; font-size:28px"><em>Anchorman 2 Arrives Soon</em></h1></span> <div id="contentbox2"></div> <!--Footer Div --> <center><div id="footer"><a href="#">Sitemap</a> <a href="#">About Us</a> <a href="#">Feedback</a></div></center> <div id="disqus"><div id="disqus_thread"></div> <script type="text/javascript"> /* * * CONFIGURATION VARIABLES: EDIT BEFORE PASTING INTO YOUR WEBPAGE * * */ var disqus_shortname = 'thetotempoleanchorman2'; // required: replace example with your forum shortname /* * * DON'T EDIT BELOW THIS LINE * * */ (function() { var dsq = document.createElement('script'); dsq.type = 'text/javascript'; dsq.async = true; dsq.src = '//' + disqus_shortname + '.disqus.com/embed.js'; (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(dsq); })(); </script> <noscript>Please enable JavaScript to view the <a href="http://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript> <a href="http://disqus.com" class="dsq-brlink">comments powered by <span class="logo-disqus">Disqus</span></a></div> <!-- This is the end of the contentbox --></div> <!-- This is the end of the container div --> </div> </body> </html> CSS: html { background: url(images/pine.jpg) no-repeat center center fixed; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover; filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src='images/pine.jpg', sizingMethod='scale'); -ms-filter: "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='images/pine.jpg', sizingMethod='scale')"; } body { margin-bottom:0px; font-family: Verdana, Geneva, sans-serif; } a { outline : none; border: none; } a:hover { color: #0FC; } #container { width: 1000px; height:1924px; position:relative; margin-right: auto; margin-left: auto; z-index:1; margin-bottom: 50px; } #facebook { position:fixed; right:100px; z-index:15; } #twitter { position:fixed; z-index:16; right:120px; } #google { position:fixed; top:7px; right: 135px; } #socialmediaplugins { text-align: right; position: fixed; background: rgb(125,126,125); /* Old browsers */ background: -moz-linear-gradient(top, rgba(125,126,125,1) 0%, rgba(247,247,247,1) 100%); /* FF3.6+ */ background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(125,126,125,1)), color-stop(100%,rgba(247,247,247,1))); /* Chrome,Safari4+ */ background: -webkit-linear-gradient(top, rgba(125,126,125,1) 0%,rgba(247,247,247,1) 100%); /* Chrome10+,Safari5.1+ */ background: -o-linear-gradient(top, rgba(125,126,125,1) 0%,rgba(247,247,247,1) 100%); /* Opera 11.10+ */ background: -ms-linear-gradient(top, rgba(125,126,125,1) 0%,rgba(247,247,247,1) 100%); /* IE10+ */ background: linear-gradient(to bottom, rgba(125,126,125,1) 0%,rgba(247,247,247,1) 100%); /* W3C */ filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#7d7e7d', endColorstr='#f7f7f7',GradientType=0 ); /* IE6-9 */ margin: 0px; top: 0px; left: 0px; right: 0px; z-index:14; } #searchbox { background-color:#01bff6; border-radius:4px; } #searchbox:hover { background-color:#76b618; border-radius:4px; } #searchbox:active { background-color:#01bff6; border-radius:4px; } #contentbox { background-color:black; background-image:url(images/wooden.jpg); width: 1000px; margin-bottom:50px; height: 1924px; box-shadow:2px 2px 10px 10px #060606; -webkit-box-shadow:2px 2px 10px 10px #060606; -moz-box-shadow:2px 2px 10px 10px #060606; /* For IE<9 */ filter: progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=0,strength=5), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=45,strength=2), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=90,strength=5), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=135,strength=5), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=180,strength=10), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=225,strength=5), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=270,strength=5), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=315,strength=2); } #contentbox2 { background-image:url(images/woodenmovies.jpg); top:299px; width: 1000px; margin-bottom:50px; height: 1625px; position: absolute; } #banner { background-image:url(images/totempolebanner.gif); position:absolute; top:25px; width:768px; height:120px; left:116px; } #navbar { float: left; position: absolute; top: 146px; left: 76px; width: 844px; height: 158px; font-weight:bold; } #navbar a { color:#0C6; font-size: 13px; } #navbar a:hover { color:#0F9; font-size: 13px; } #navbar2 a:hover { color:#0F9; } #navbar2 a{ text-decoration:none; color:#0C6; } #navbar2 { position: absolute; top: 4px; left: 766px; width: 273px; height: 24px; font-size: 11px; } #searchbar { position: absolute; top: 23px; left: 885px; width: 118px; height: 69px; } .css_btn_class { font-size:9px; position: relative; top:0px; right:4px; width:90px; height:25px; font-family:Verdana; font-weight:normal; -moz-border-radius:7px; -webkit-border-radius:7px; border-radius:7px; border:1px solid #35d914; padding:7px 24px; text-decoration:none; background:-webkit-gradient( linear, left top, left bottom, color-stop(5%, #ff9d00), color-stop(100%, #ffe711) ); background:-moz-linear-gradient( center top, #ff9d00 5%, #ffe711 100% ); background:-ms-linear-gradient( top, #ff9d00 5%, #ffe711 100% ); background-color:#ff9d00; color:#ff0000; display:inline-block; text-shadow:0px 0px 1px #117cff; -webkit-box-shadow: 0px 0px 0px 0px #117cff; -moz-box-shadow: 0px 0px 0px 0px #117cff; box-shadow: 0px 0px 0px 0px #117cff; background-image: url(images/unnamed.gif); background-repeat:no-repeat; background-position:right; }.css_btn_class:hover { width:90px; background:-webkit-gradient( linear, left top, left bottom, color-stop(5%, #ffe711), color-stop(100%, #ff9d00) ); background:-moz-linear-gradient( center top, #ffe711 5%, #ff9d00 100% ); background:-ms-linear-gradient( top, #ffe711 5%, #ff9d00 100% ); background-color:#ffe711; background-image: url(images/unnamed.gif); background-repeat:no-repeat; background-position:right; }.css_btn_class:active { position:relative; width:90px; top:1px; background-image: url(images/unnamed.gif); background-repeat:no-repeat; background-position:right; } /* This css button was generated by css-button-generator.com */ img {border:none;} #eagle { position:relative; right: 144px; top:299px; } #owl { top:624px; position:absolute; left:0px; } #wolf { top:949px; position:absolute; right:0px; } #hare { top:1274px; position:absolute; left:0px; } #bear { top:1599px; position:absolute; right:0px; } #footer { position: absolute; left: 393px; top: 1941px; width: 251px; color: #0F9; } #footer a { color: #0f9; } .atss { left: 0; } #infocontent { position: absolute; z-index: 3; left: 15px; top: 333px; height: 348px; width: 789px; } #mywowslider { position: absolute; z-index: 3; left: 640px; top: 684px; } #poll { position: absolute; z-index: 3; left: 815px; top: 344px; } #trailer1 { position: absolute; z-index: 3; left: 40px; top: 598px; } #trailer2 { position: absolute; z-index: 3; left: 40px; top: 948px; } #trailer1header { position: absolute; z-index: 3; left: 200px; top: 550px; width: 240px; font-style: italic; font-weight: normal; } #trailer2header { position: absolute; z-index: 3; left: 200px; top: 898px; width: 241px; height: 51px; font-style: italic; font-weight: normal; } #disqus { position: absolute; z-index: 3; left: 0px; top: 1340px; } #sources { position: absolute; z-index: 3; left: 394px; top: 1249px; width: 212px; }

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• Can my loop be optimized any more? (C++)

  - by Sagekilla

  Below is one of my inner loops that's run several thousand times, with input sizes of 20 - 1000 or more. Is there anything I can do to help squeeze any more performance out of this? I'm not looking to move this code to something like using tree codes (Barnes-Hut), but towards optimizing the actual calculations happening inside, since the same calculations occur in the Barnes-Hut algorithm. Any help is appreciated! typedef double real; struct Particle { Vector pos, vel, acc, jerk; Vector oldPos, oldVel, oldAcc, oldJerk; real mass; }; class Vector { private: real vec[3]; public: // Operators defined here }; real Gravity::interact(Particle *p, size_t numParticles) { PROFILE_FUNC(); real tau_q = 1e300; for (size_t i = 0; i < numParticles; i++) { p[i].jerk = 0; p[i].acc = 0; } for (size_t i = 0; i < numParticles; i++) { for (size_t j = i+1; j < numParticles; j++) { Vector r = p[j].pos - p[i].pos; Vector v = p[j].vel - p[i].vel; real r2 = lengthsq(r); real v2 = lengthsq(v); // Calculate inverse of |r|^3 real r3i = Constants::G * pow(r2, -1.5); // da = r / |r|^3 // dj = (v / |r|^3 - 3 * (r . v) * r / |r|^5 Vector da = r * r3i; Vector dj = (v - r * (3 * dot(r, v) / r2)) * r3i; // Calculate new acceleration and jerk p[i].acc += da * p[j].mass; p[i].jerk += dj * p[j].mass; p[j].acc -= da * p[i].mass; p[j].jerk -= dj * p[i].mass; // Collision estimation // Metric 1) tau = |r|^2 / |a(j) - a(i)| // Metric 2) tau = |r|^4 / |v|^4 real mij = p[i].mass + p[j].mass; real tau_est_q1 = r2 / (lengthsq(da) * mij * mij); real tau_est_q2 = (r2*r2) / (v2*v2); if (tau_est_q1 < tau_q) tau_q = tau_est_q1; if (tau_est_q2 < tau_q) tau_q = tau_est_q2; } } return sqrt(sqrt(tau_q)); }

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• C# Detect Localhost Port Usage

  - by ThaKidd

  In advance, thank you for your advice. I am currently working on a program which uses Putty to create a SSH connection with a server that uses local port forwarding to enable a client, running my software, to access the service behind the SSH server via localhost. IE: client:20100 - Internet - Remote SSH server exposed via router/firewall - Local Intranet - Intranet Web POP3 Server:110. Cmd Line: "putty -ssh -2 -P 22 -C -L 20100:intranteIP:110 -pw sshpassword sshusername@sshserver" Client would use putty to create a SSH connection with the SSH server specifying in the connection string that it would like to tie port 110 of the Intranet POP3 Server to port 20100 on the client system. Therefore the client would be able to open up a mail client to localhost:20100 and interact with the Internal POP3 server over the SSH tunnel. The above is a general description. I already know what I am trying to do will work without a problem so am not looking for debate on the above. The question is this...How can I ensure the local port (I cannot use dynamic ports, so it must be static) on localhost is not being used or listened to by any other application? I am currently executing this code in my C# app: private bool checkPort(int port) { try { //Create a socket on the current IPv4 address Socket TestSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); // Create an IP end point IPEndPoint localIP = new IPEndPoint(IPAddress.Parse("127.0.0.1"), port); // Bind that port TestSocket.Bind(localIP); // Cleanup TestSocket.Close(); return false; } catch (Exception e) { // Exception occurred. Port is already bound. return true; } } I am currently calling this function starting with a specific port in a for loop to get the 'false' return at the first available port. The first port I try is actually being listened to by uTorrent. The above code does not catch this and my connection fails. What is the best method to ensure a port is truly free? I do understand some other program may grab the port during/after I have tested it. I just need to find something that will ensure it is not currently in use AT ALL when the test is executed. If there is a way to truly reserve the localhost port during the test, I would love to hear about it.

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• A scheme for expiring downloaded content?

  - by Chad Johnson

  I am going to offer a web API service that allows users to download and "rent" content for a monthly subscription fee. The API will either be open to everyone or possibly just select parties (not sure yet). Each developer must agree to a license, and they receive a developer key for their person. Each software application will have its own key as well. So then end-users will download the software which will interact with my service's API. Each user will have a key for each application as well (probably using OAuth). Content will be cached on first download and accessible offline via just the third-party application that cached the content. If a user cancels their subscription, I plan on doing the following: Deactivate the user's OAuth key for all applications. Do not allow the user's account to download new content via the API (and subsequently any software that uses the API). Now, the big question is: how do I make content expire if they cancel their subscription? If they cancel, they should not have access to content anymore. Here are ideas I've thought of (some of these are half-solutions, not yet fully fleshed out): Require that applications encrypt downloaded content using the user's OAuth key, making it available to only the application. This will prevent most users from going to the cache directory and just copying and keeping files. Update the user's key once a month, forcing content to re-cache on a monthly basic. Users could then access content for a month after they cancel their subscription. Require applications to "phone home" [to the service] periodically and check whether the user's subscription has terminated. If so, require in the API developer license that applications expire cache. If it is found that applications do not comply, their keys (and possibly keys for all developers) are permanently deactivated as a consequence. One major worry is that some applications may blatantly ignore constraints of the license. Is it generally acceptable to rely on applications abiding by the licensing constraints? Bad idea? Any other ideas? Maybe a way to make content auto-expire after x days? Something else? I'm open to out-of-the-box ideas.

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• MVC pattern implementation. What is the n-relation between its components

  - by Srodriguez

  Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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• MVC pattern implementation. What is the n-relation between its components

  - by Srodriguez

  Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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• How to avoid repetition when working with primitive types?

  - by I82Much

  I have the need to perform algorithms on various primitive types; the algorithm is essentially the same with the exception of which type the variables are. So for instance, /** * Determine if <code>value</code> is the bitwise OR of elements of <code>validValues</code> array. * For instance, our valid choices are 0001, 0010, and 1000. * We are given a value of 1001. This is valid because it can be made from * ORing together 0001 and 1000. * On the other hand, if we are given a value of 1111, this is invalid because * you cannot turn on the second bit from left by ORing together those 3 * valid values. */ public static boolean isValid(long value, long[] validValues) { for (long validOption : validValues) { value &= ~validOption; } return value != 0; } public static boolean isValid(int value, int[] validValues) { for (int validOption : validValues) { value &= ~validOption; } return value != 0; } How can I avoid this repetition? I know there's no way to genericize primitive arrays, so my hands seem tied. I have instances of primitive arrays and not boxed arrays of say Number objects, so I do not want to go that route either. I know there are a lot of questions about primitives with respect to arrays, autoboxing, etc., but I haven't seen it formulated in quite this way, and I haven't seen a decisive answer on how to interact with these arrays. I suppose I could do something like: public static<E extends Number> boolean isValid(E value, List<E> numbers) { long theValue = value.longValue(); for (Number validOption : numbers) { theValue &= ~validOption.longValue(); } return theValue != 0; } and then public static boolean isValid(long value, long[] validValues) { return isValid(value, Arrays.asList(ArrayUtils.toObject(validValues))); } public static boolean isValid(int value, int[] validValues) { return isValid(value, Arrays.asList(ArrayUtils.toObject(validValues))); } Is that really much better though? Any thoughts in this matter would be appreciated.

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