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  • how to implement a "soft barrier" in multithreaded c++

    - by Jason
    I have some multithreaded c++ code with the following structure: do_thread_specific_work(); update_shared_variables(); //checkpoint A do_thread_specific_work_not_modifying_shared_variables(); //checkpoint B do_thread_specific_work_requiring_all_threads_have_updated_shared_variables(); What follows checkpoint B is work that could have started if all threads have reached only checkpoint A, hence my notion of a "soft barrier". Typically multithreading libraries only provide "hard barriers" in which all threads must reach some point before any can continue. Obviously a hard barrier could be used at checkpoint B. Using a soft barrier can lead to better execution time, especially since the work between checkpoints A and B may not be load-balanced between the threads (i.e. 1 slow thread who has reached checkpoint A but not B could be causing all the others to wait at the barrier just before checkpoint B). I've tried using atomics to synchronize things and I know with 100% certainty that is it NOT guaranteed to work. For example using openmp syntax, before the parallel section start with: shared_thread_counter = num_threads; //known at compile time #pragma omp flush Then at checkpoint A: #pragma omp atomic shared_thread_counter--; Then at checkpoint B (using polling): #pragma omp flush while (shared_thread_counter > 0) { usleep(1); //can be removed, but better to limit memory bandwidth #pragma omp flush } I've designed some experiments in which I use an atomic to indicate that some operation before it is finished. The experiment would work with 2 threads most of the time but consistently fail when I have lots of threads (like 20 or 30). I suspect this is because of the caching structure of modern CPUs. Even if one thread updates some other value before doing the atomic decrement, it is not guaranteed to be read by another thread in that order. Consider the case when the other value is a cache miss and the atomic decrement is a cache hit. So back to my question, how to CORRECTLY implement this "soft barrier"? Is there any built-in feature that guarantees such functionality? I'd prefer openmp but I'm familiar with most of the other common multithreading libraries. As a workaround right now, I'm using a hard barrier at checkpoint B and I've restructured my code to make the work between checkpoint A and B automatically load-balancing between the threads (which has been rather difficult at times). Thanks for any advice/insight :)

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  • dynamiclly schedule a lead sales agent

    - by Josh
    I have a website that I'm trying to migrate from classic asp to asp.net. It had a lead schedule, where each sales agent would be featured for the current day, or part of the day.The next day a new agent would be scheduled. It was driven off a database table that had a row for each day in it. So to figure out if a sales agent would show on a day, it was easy, just find today's date in the table. Problem was it ran out rows, and you had to run a script to update the lead days 6 months at a time. Plus if there was ever any change to the schedule, you had to delete all the rows and re-run the script. So I'm trying to code it where sql server figures that out for me, and no script has to be ran. I have a table like so CREATE TABLE [dbo].[LeadSchedule]( [leadid] [int] IDENTITY(1,1) NOT NULL, [userid] [int] NOT NULL, [sunday] [bit] NOT NULL, [monday] [bit] NOT NULL, [tuesday] [bit] NOT NULL, [wednesday] [bit] NOT NULL, [thursday] [bit] NOT NULL, [friday] [bit] NOT NULL, [saturday] [bit] NOT NULL, [StartDate] [smalldatetime] NULL, [EndDate] [smalldatetime] NULL, [StartTime] [time](0) NULL, [EndTime] [time](0) NULL, [order] [int] NULL, So the user can schedule a sales agent depending on their work schedule. Also if they wanted to they could split certain days, or sales agents by time, So from Midnight to 4 it was one agent, from 4-midnight it was another. So far I've tried using a numbers table, row numbers, goofy date math, and I'm at a loss. Any suggestions on how to handle this purely from sql code? If it helps, the table should always be small, like less than 20 never over 100. update After a few hours all I've managed to come up with is the below. It doesn't handle filling in days not available or times, just rotates through all the sales agents with leadTable as ( select leadid,userid,[order],StartDate, case DATEPART(dw,getdate()) when 1 then sunday when 2 then monday when 3 then tuesday when 4 then wednesday when 5 then thursday when 6 then friday when 7 then saturday end as DayAvailable , ROW_NUMBER() OVER (ORDER BY [order] ASC) AS ROWID from LeadSchedule where GETDATE()>=StartDate and (CONVERT(time(0),GETDATE())>= StartTime or StartTime is null) and (CONVERT(time(0),GETDATE())<= EndTime or EndTime is null) ) select userid, DATEADD(d,(number+ROWID-2)*totalUsers,startdate ) leadday from (select *, (select COUNT(1) from leadTable) totalUsers from leadTable inner join Numbers on 1=1 where DayAvailable =1 ) tb1 order by leadday asc

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  • Silverlight? WPF? or Windows Form?

    - by Amit
    After Silverlight 4.0 has been released with new WPF, I am kind of confused with these technologies: Silverlight? WPF? Windows Form? The main motive that we want to achieve for BIG business project is following: Performance Security And platform independent** If I consider all above three points then only Silverlight is the option as I don’t want people buying emulator on MacOS for WPF or Windows Form. Now how good the Silverlight is for Business applications, I was completely against when Silverlight 2.0 was in the market but now it is Silverlight 4.0 and they have provided many new features (but still basics) that is required in any challenging business applications. Comparing Silverlight and WPF -* Silverlight and WPF are very new technology and if I'd to compare from these two then I'd prefer WPF because it can be considered stable and mature. But it is not same as Windows Form. -* If I go with Silverlight then I am sure about keep updating to the latest version of Silverlight. I remembered when we were developing software for version 2.0 then we'd to create our own framework with dynamic loading DLL, and then Navigation concept. But everything was got changed once Silverlight 3.0 came. I don't want this to be happening with this new product. -* If we go with WPF then we don't get the platform independence. Now, why not we just focus on making WPF and then move to Silverlght. As someone (Tim?) from Microsoft has said that the idea is to make Silverlight as close as WPF. But if that is the case then why XAML structure is different; I will not be convinced with by saying that .Net framework for SL is too small.. well the difference is coming from the namespace ? I was searching on this subject and found "Microsoft WPF-Silverlight Comparison Whitepaper v1.1.pdf". This guide is very good that gives you ins-outs about how can we build common apps that runs on both. But again, it is comparing Silverlight 2 and not 4. I am sure many architect/ developers/ project managers must be facing similar kind of questions in their premises and wants to initiate this discussion, if it has not been :). We've still got 2 weeks to make this decision, so I'm expecting everyone to participate, gurus?

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  • How can I limit the cache used by copying so there is still memory available for other cache?

    - by Peter
    Basic situation: I am copying some NTFS disks in openSuSE. Each one is 2TB. When I do this, the system runs slow. My guesses: I believe it is likely due to caching. Linux decides to discard useful cache (eg. kde4 bloat, virtual machine disks, LibreOffice binaries, Thunderbird binaries, etc.) and instead fill all available memory (24 GB total) with stuff from the copying disks, which will be read only once, then written and never used again. So then any time I use these apps (or kde4), the disk needs to be read again, and reading the bloat off the disk again makes things freeze/hiccup. Due to the cache being gone and the fact that these bloated applications need lots of cache, this makes the system horribly slow. Since it is USB,the disk and disk controller are not the bottleneck, so using ionice does not make it faster. I believe it is the cache rather than just the motherboard going too slow, because if I stop everything copying, it still runs choppy for a while until it recaches everything. And if I restart the copying, it takes a minute before it is choppy again. But also, I can limit it to around 40 MB/s, and it runs faster again (not because it has the right things cached, but because the motherboard busses have lots of extra bandwidth for the system disks). I can fully accept a performance loss from my motherboard's IO capability being completely consumed (which is 100% used, meaning 0% wasted power which makes me happy), but I can't accept that this caching mechanism performs so terribly in this specific use case. # free total used free shared buffers cached Mem: 24731556 24531876 199680 0 8834056 12998916 -/+ buffers/cache: 2698904 22032652 Swap: 4194300 24764 4169536 I also tried the same thing on Ubuntu, which causes a total system hang instead. ;) And to clarify, I am not asking how to leave memory free for the "system", but for "cache". I know that cache memory is automatically given back to the system when needed, but my problem is that it is not reserved for caching of specific things. Question: Is there some way to tell these copy operations to limit memory usage so some important things remain cached, and therefore any slowdowns are a result of normal disk usage and not rereading the same commonly used files? For example, is there a setting of max memory per process/user/file system allowed to be used as cache/buffers?

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  • Forcing a checkbox bound to a DataSource to update when it has not been viewed yet.

    - by Scott Chamberlain
    Here is a test framework to show what I am doing: create a new project add a tabbed control on tab 1 put a button on tab 2 put a check box paste this code for its code (use default names for controls) public partial class Form1 : Form { private List<bool> boolList = new List<bool>(); BindingSource bs = new BindingSource(); public Form1() { InitializeComponent(); boolList.Add(false); bs.DataSource = boolList; checkBox1.DataBindings.Add("Checked", bs, ""); this.button1.Click += new System.EventHandler(this.button1_Click); this.checkBox1.CheckedChanged += new System.EventHandler(this.checkBox1_CheckedChanged); } bool updating = false; private void button1_Click(object sender, EventArgs e) { updating = true; boolList[0] = true; bs.ResetBindings(false); Application.DoEvents(); updating = false; } private void checkBox1_CheckedChanged(object sender, EventArgs e) { if (!updating) MessageBox.Show("CheckChanged fired outside of updating"); } } The issue is if you run the program and look at tab 2 then press the button on tab 1 the program works as expected, however if you press the button on tab 1 then look at tab 2 the event for the checkbox will not fire untill you look at tab 2. The reason for this is the controll on tab 2 is not in the "created" state, so its binding to change the checkbox from unchecked to checked does not happen until after the control has been "Created". checkbox1.CreateControl() does not do anything because according to MSDN CreateControl does not create a control handle if the control's Visible property is false. You can either call the CreateHandle method or access the Handle property to create the control's handle regardless of the control's visibility, but in this case, no window handles are created for the control's children. I tried getting the value of Handle(there is no public CreateHandle() for CheckBox) but still the same result. Any suggestions other than have the program quickly flash all of my tabs that have data-bound check boxes when it first loads? EDIT-- per Jaxidian's suggestion I created a new class public class newcheckbox : CheckBox { public new void CreateHandle() { base.CreateHandle(); } } I call CreateHandle() right after updating = true same results as before.

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  • ASP.Net 4.0 - Response required in SiteMap building?

    - by Nick Craver
    I'm running into an issue upgrading a project to .Net 4.0...and having trouble finding any reason for the issue (or at least, the change causing it). Given the freshness of 4.0, not a lot of blogs out there for issues yet, so I'm hoping someone here has an idea. Preface: this is a Web Forms application, coming from 3.5 SP1 to 4.0. In the Application_Start event we're iterating through the SiteMap and constructing routes based off data there (prettifying URLs mostly with some utility added), that part isn't failing though...or at least isn't not getting that far. It seems that calling the SiteMap.RootNode (inside application_start) causes 4.0 to eat it, since the XmlSiteMapProvider.GetNodeFromXmlNode method has been changed, looking in reflector you can see it's hitting HttpResponse.ApplyAppPathModifier here: str2 = HttpContext.Current.Response.ApplyAppPathModifier(str2); HttpResponse wasn't used at all in this method in the 2.0 CLR, so what we had worked fine, in 4.0 though, that method is called as a result of this stack: [HttpException (0x80004005): Response is not available in this context.] System.Web.XmlSiteMapProvider.GetNodeFromXmlNode(XmlNode xmlNode, Queue queue) System.Web.XmlSiteMapProvider.ConvertFromXmlNode(Queue queue) System.Web.XmlSiteMapProvider.BuildSiteMap() System.Web.XmlSiteMapProvider.get_RootNode() System.Web.SiteMap.get_RootNode() Since Response isn't available here in 4.0, we get an error. To reproduce this, you can narrow the test case down to this in global: protected void Application_Start(object sender, EventArgs e) { var s = SiteMap.RootNode; //Kaboom! //or just var r = Context.Response; //or var r = HttpContext.Current.Response; //all result in the same "not available" error } Question: Am I missing something obvious here? Or, is there another event added in 4.0 that's recommended for anything related to SiteMap on startup? For anyone curious/willing to help, I've created a very minimal project (a default VS 2010 ASP.Net 4.0 site, all the bells & whistles removed and only a blank sitemap and the Application_Start code added). It's a small 10kb zip available here: http://www.ncraver.com/Test/SiteMapTest.zip Update: Not a great solution, but the current work-around is to do the work in Application_BeginRequest, like this: private static bool routesRegistered = false; protected void Application_BeginRequest(object sender, EventArgs e) { if (!routesRegistered) { Application.Lock(); if (!routesRegistered) RouteManager.RegisterRoutes(RouteTable.Routes); routesRegistered = true; Application.UnLock(); } } I don't like this particularly, feels like an abuse of the event to bypass the issue. Does anyone have at least a better work-around, since the .Net 4 behavior with SiteMap is not likely to change?

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  • Java getInputStreat SocketTimeoutException instead of NoRouteToHostException

    - by Jon
    I have an odd issue happening when trying to open multiple Input Streams (in separate threads) on Linux (RHEL). The behaviour works as expected on windows. I am kicking off 3 threads to open https connections to 3 different servers. All three are invalid IP addresses (in this test case), so I expect an NoRouteToHostException for each of them. The first two return these as expected, and quite quickly. (see stack trace below) However the third (and 4th when I tested it that way) do NOT give a no route exception. They wait for ages, and then give a SocketTimeoutException (see other stack trace below). This takes ages to come back, and does not accurately express the connection issue. The offending line of code is: reader = new BufferedReader(new InputStreamReader(conn.getInputStream())); Has anyone seen something like this before? Are there multi-threading issues with sockets on REHL or some limit somewhere to how many can connect at once...or...something? Expected stack trace, as received for first two: java.net.NoRouteToHostException: No route to host at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:529) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:559) at sun.net.NetworkClient.doConnect(NetworkClient.java:158) at sun.net.www.http.HttpClient.openServer(HttpClient.java:394) at sun.net.www.http.HttpClient.openServer(HttpClient.java:529) at sun.net.www.protocol.https.HttpsClient.(HttpsClient.java:272) at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:329) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:172) at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:916) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:158) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1177) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:234) Unexpected stack trace, as received on 3rd: java.net.SocketTimeoutException: connect timed out at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:529) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:559) at sun.net.NetworkClient.doConnect(NetworkClient.java:158) at sun.net.www.http.HttpClient.openServer(HttpClient.java:394) at sun.net.www.http.HttpClient.openServer(HttpClient.java:529) at sun.net.www.protocol.https.HttpsClient.(HttpsClient.java:272) at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:329) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:172) at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:916) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:158) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1177) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:234)

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  • Powershell $LastExitCode=0 but $?=False . Redirecting stderr to stdout gives NativeCommandError

    - by Colonel Panic
    Can anyone explain Powershell's surprising behaviour in the second example below? First, a example of sane behaviour: PS C:\> & cmd /c "echo Hello from standard error 1>&2"; echo "`$LastExitCode=$LastExitCode and `$?=$?" Hello from standard error $LastExitCode=0 and $?=True No surprises. I print a message to standard error (using cmd's echo). I inspect the variables $? and $LastExitCode. They equal to True and 0 respectively, as expected. However, if I ask Powershell to redirect standard error to standard output over the first command, I get a NativeCommandError: PS C:\> & cmd /c "echo Hello from standard error 1>&2" 2>&1; echo "`$LastExitCode=$LastExitCode and `$?=$?" cmd.exe : Hello from standard error At line:1 char:4 + cmd <<<< /c "echo Hello from standard error 1>&2" 2>&1; echo "`$LastExitCode=$LastExitCode and `$?=$?" + CategoryInfo : NotSpecified: (Hello from standard error :String) [], RemoteException + FullyQualifiedErrorId : NativeCommandError $LastExitCode=0 and $?=False My first question, why the NativeCommandError ? Secondly, why is $? False when cmd ran successfully and $LastExitCode is 0? Powershell's docs about_Automatic_Variables don't explicitly define $?. I always supposed it is True if and only if $LastExitCode is 0 but my example contradicts that. Here's how I came across this behaviour in the real-world (simplified). It really is FUBAR. I was calling one Powershell script from another. The inner script: cmd /c "echo Hello from standard error 1>&2" if (! $?) { echo "Job failed. Sending email.." exit 1 } # do something else Running this simply .\job.ps1, it works fine, no email is sent. However, I was calling it from another Powershell script, logging to a file .\job.ps1 2>&1 > log.txt. In this case, an email is sent! Here, the act of observing a phenomenon changes its outcome. This feels like quantum physics rather than scripting! [Interestingly: .\job.ps1 2>&1 may or not blow up depending on where you run it]

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  • Unlocking a mutex from a different thread (C++)

    - by dan
    I'm using the C++ boost::thread library, which in my case means I'm using pthreads. Officially, a mutex must be unlocked from the same thread which locks it, and I want the effect of being able to lock in one thread and then unlock in another. There are many ways to accomplish this. One possibility would be to write a new mutex class which allows this behavior. For example: class inter_thread_mutex{ bool locked; boost::mutex mx; boost::condition_variable cv; public: void lock(){ boost::unique_lock<boost::mutex> lck(mx); while(locked) cv.wait(lck); locked=true; } void unlock(){ { boost::lock_guard<boost::mutex> lck(mx); if(!locked) error(); locked=false; } cv.notify_one(); } // bool try_lock(); void error(); etc. } I should point out that the above code doesn't guarantee FIFO access, since if one thread calls lock() while another calls unlock(), this first thread may acquire the lock ahead of other threads which are waiting. (Come to think of it, the boost::thread documentation doesn't appear to make any explicit scheduling guarantees for either mutexes or condition variables). But let's just ignore that (and any other bugs) for now. My question is, if I decide to go this route, would I be able to use such a mutex as a model for the boost Lockable concept. For example, would anything go wrong if I use a boost::unique_lock< inter_thread_mutex for RAII-style access, and then pass this lock to boost::condition_variable_any.wait(), etc. On one hand I don't see why not. On the other hand, "I don't see why not" is usually a very bad way of determining whether something will work. The reason I ask is that if it turns out that I have to write wrapper classes for RAII locks and condition variables and whatever else, then I'd rather just find some other way to achieve the same effect.

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  • Why my application ask for a codec to pla the MVI(.MOV) video files while i can play them on WMP and QuickTime?

    - by Daniel Lip
    I have an application i did some time ago when im loading the video file its ok when trying to play/use the file im getting the messageBox message say that its need a codec to use gspot or search the internet. Wehn im playing this files on my hard disk with Windows Media Play or either QuickTime there is no problems. The Video files for example name are: MVI_2483 in the file name properties i see its type: Quick Time Movie (.MOV) In my application im using DirectShowLib-2005.dll this is the class im using in my case to extract the video file im using it in my application to extract only lightnings from the video file name. In Form1 i have a button click event that just starting the action: private void button8_Click(object sender, EventArgs e) { viewToolStripMenuItem.Enabled = false; fileToolStripMenuItem.Enabled = false; button2.Enabled = false; label14.Visible = false; label15.Visible = false; label21.Visible = false; label22.Visible = false; label24.Visible = false; label25.Visible = false; ExtractAutomatic = true; DirectoryInfo info = new DirectoryInfo(_videoFile); string dirName = info.Name; automaticModeDirectory = dirName + "_Automatic"; subDirectoryName = _outputDir + "\\" + automaticModeDirectory; if (secondPass == true) { Start(true); } Start(false); } This is the function start in Form1: private void Start(bool secondpass) { setpicture(-1); if (Directory.Exists(_outputDir) && secondpass == false) { } else { Directory.CreateDirectory(_outputDir); } if (ExtractAutomatic == true) { string subDirectory_Automatic_Name = _outputDir + "\\" + automaticModeDirectory; Directory.CreateDirectory(subDirectory_Automatic_Name); f = new WmvAdapter(_videoFile, Path.Combine(subDirectory_Automatic_Name)); } else { string subDirectory_Manual_Name; if (Directory.Exists(subDirectoryName)) { subDirectory_Manual_Name = subDirectoryName; f = new WmvAdapter(_videoFile, Path.Combine(subDirectory_Manual_Name)); } else { subDirectory_Manual_Name = _outputDir + "\\" + averagesListTextFileDirectory + "_Manual"; Directory.CreateDirectory(subDirectory_Manual_Name); f = new WmvAdapter(_videoFile, Path.Combine(subDirectory_Manual_Name)); } } button1.Enabled = false; f.Secondpass = secondpass; f.FramesToSave = _fts; f.FrameCountAvailable += new WmvAdapter.FrameCountEventHandler(f_FrameCountAvailable); f.StatusChanged += new WmvAdapter.EventHandler(f_StatusChanged); f.ProgressChanged += new WmvAdapter.ProgressEventHandler(f_ProgressChanged); this.Text = "Processing Please Wait..."; label5.ForeColor = Color.Green; label5.Text = "Processing Please Wait"; button8.Enabled = false; button5.Enabled = false; label5.Visible = true; pictureBox1.Image = Lightnings_Extractor.Properties.Resources.Weather_Michmoret; Hrs = 0; //number of hours Min = 0; //number of Minutes Sec = 0; //number of Sec timeElapsed = 0; label10.Text = "00:00:00"; label11.Visible = false; label12.Visible = false; label9.Visible = false; label8.Visible = false; this.button1.Enabled = false; myTrackPanelss1.trackBar1.Enabled = false; this.checkBox2.Enabled = false; this.checkBox1.Enabled = false; numericUpDown1.Enabled = false; timer1.Start(); label2.Text = ""; label1.Visible = true; label2.Visible = true; label3.Visible = true; label4.Visible = true; f.Start(); } And this is the class wich is not my oqn class i just just defined it in some places wich making the problem: using System; using System.Diagnostics; using System.Drawing; using System.Drawing.Imaging; using System.IO; using System.Runtime.InteropServices; using DirectShowLib; using System.Collections.Generic; using Extracting_Frames; using System.Windows.Forms; namespace Polkan.DataSource { internal class WmvAdapter : ISampleGrabberCB, IDisposable { #region Fields_Properties_and_Events bool dis = false; int count = 0; const string fileName = @"d:\histogramValues.dat"; private IFilterGraph2 _filterGraph; private IMediaControl _mediaCtrl; private IMediaEvent _mediaEvent; private int _width; private int _height; private readonly string _outFolder; private int _frameId; //better use a custom EventHandler that passes the results of the action to the subscriber. public delegate void EventHandler(object sender, EventArgs e); public event EventHandler StatusChanged; public delegate void FrameCountEventHandler(object sender, FrameCountEventArgs e); public event FrameCountEventHandler FrameCountAvailable; public delegate void ProgressEventHandler(object sender, ProgressEventArgs e); public event ProgressEventHandler ProgressChanged; private IMediaSeeking _mSeek; private long _duration = 0; private long _avgFrameTime = 0; //just save the averages to a List (not to fs) public List<double> AveragesList { get; set; } public List<long> histogramValuesList; public bool Secondpass { get; set; } public List<int> FramesToSave { get; set; } #endregion #region Constructors and Destructors public WmvAdapter(string file, string outFolder) { _outFolder = outFolder; try { SetupGraph(file); } catch { Dispose(); MessageBox.Show("A codec is required to load this video file. Please use http://www.headbands.com/gspot/ or search the web for the correct codec"); } } ~WmvAdapter() { CloseInterfaces(); } #endregion public void Dispose() { CloseInterfaces(); } public void Start() { EstimateFrameCount(); int hr = _mediaCtrl.Run(); WaitUntilDone(); DsError.ThrowExceptionForHR(hr); } public void WaitUntilDone() { int hr; const int eAbort = unchecked((int)0x80004004); do { System.Windows.Forms.Application.DoEvents(); EventCode evCode; if (dis == true) { return; } hr = _mediaEvent.WaitForCompletion(100, out evCode); }while (hr == eAbort); DsError.ThrowExceptionForHR(hr); OnStatusChanged(); } //Edit: added events protected virtual void OnStatusChanged() { if (StatusChanged != null) StatusChanged(this, new EventArgs()); } protected virtual void OnFrameCountAvailable(long frameCount) { if (FrameCountAvailable != null) FrameCountAvailable(this, new FrameCountEventArgs() { FrameCount = frameCount }); } protected virtual void OnProgressChanged(int frameID) { if (ProgressChanged != null) ProgressChanged(this, new ProgressEventArgs() { FrameID = frameID }); } /// <summary> build the capture graph for grabber. </summary> private void SetupGraph(string file) { ISampleGrabber sampGrabber = null; IBaseFilter capFilter = null; IBaseFilter nullrenderer = null; _filterGraph = (IFilterGraph2)new FilterGraph(); _mediaCtrl = (IMediaControl)_filterGraph; _mediaEvent = (IMediaEvent)_filterGraph; _mSeek = (IMediaSeeking)_filterGraph; var mediaFilt = (IMediaFilter)_filterGraph; try { // Add the video source int hr = _filterGraph.AddSourceFilter(file, "Ds.NET FileFilter", out capFilter); DsError.ThrowExceptionForHR(hr); // Get the SampleGrabber interface sampGrabber = new SampleGrabber() as ISampleGrabber; var baseGrabFlt = sampGrabber as IBaseFilter; ConfigureSampleGrabber(sampGrabber); // Add the frame grabber to the graph hr = _filterGraph.AddFilter(baseGrabFlt, "Ds.NET Grabber"); DsError.ThrowExceptionForHR(hr); // --------------------------------- // Connect the file filter to the sample grabber // Hopefully this will be the video pin, we could check by reading it's mediatype IPin iPinOut = DsFindPin.ByDirection(capFilter, PinDirection.Output, 0); // Get the input pin from the sample grabber IPin iPinIn = DsFindPin.ByDirection(baseGrabFlt, PinDirection.Input, 0); hr = _filterGraph.Connect(iPinOut, iPinIn); DsError.ThrowExceptionForHR(hr); // Add the null renderer to the graph nullrenderer = new NullRenderer() as IBaseFilter; hr = _filterGraph.AddFilter(nullrenderer, "Null renderer"); DsError.ThrowExceptionForHR(hr); // --------------------------------- // Connect the sample grabber to the null renderer iPinOut = DsFindPin.ByDirection(baseGrabFlt, PinDirection.Output, 0); iPinIn = DsFindPin.ByDirection(nullrenderer, PinDirection.Input, 0); hr = _filterGraph.Connect(iPinOut, iPinIn); DsError.ThrowExceptionForHR(hr); // Turn off the clock. This causes the frames to be sent // thru the graph as fast as possible hr = mediaFilt.SetSyncSource(null); DsError.ThrowExceptionForHR(hr); // Read and cache the image sizes SaveSizeInfo(sampGrabber); //Edit: get the duration hr = _mSeek.GetDuration(out _duration); DsError.ThrowExceptionForHR(hr); } finally { if (capFilter != null) { Marshal.ReleaseComObject(capFilter); } if (sampGrabber != null) { Marshal.ReleaseComObject(sampGrabber); } if (nullrenderer != null) { Marshal.ReleaseComObject(nullrenderer); } GC.Collect(); } } private void EstimateFrameCount() { try { //1sec / averageFrameTime double fr = 10000000.0 / _avgFrameTime; double frameCount = fr * (_duration / 10000000.0); OnFrameCountAvailable((long)frameCount); } catch { } } public double framesCounts() { double fr = 10000000.0 / _avgFrameTime; double frameCount = fr * (_duration / 10000000.0); return frameCount; } private void SaveSizeInfo(ISampleGrabber sampGrabber) { // Get the media type from the SampleGrabber var media = new AMMediaType(); int hr = sampGrabber.GetConnectedMediaType(media); DsError.ThrowExceptionForHR(hr); if ((media.formatType != FormatType.VideoInfo) || (media.formatPtr == IntPtr.Zero)) { throw new NotSupportedException("Unknown Grabber Media Format"); } // Grab the size info var videoInfoHeader = (VideoInfoHeader)Marshal.PtrToStructure(media.formatPtr, typeof(VideoInfoHeader)); _width = videoInfoHeader.BmiHeader.Width; _height = videoInfoHeader.BmiHeader.Height; //Edit: get framerate _avgFrameTime = videoInfoHeader.AvgTimePerFrame; DsUtils.FreeAMMediaType(media); GC.Collect(); } private void ConfigureSampleGrabber(ISampleGrabber sampGrabber) { var media = new AMMediaType { majorType = MediaType.Video, subType = MediaSubType.RGB24, formatType = FormatType.VideoInfo }; int hr = sampGrabber.SetMediaType(media); DsError.ThrowExceptionForHR(hr); DsUtils.FreeAMMediaType(media); GC.Collect(); hr = sampGrabber.SetCallback(this, 1); DsError.ThrowExceptionForHR(hr); } private void CloseInterfaces() { try { if (_mediaCtrl != null) { _mediaCtrl.Stop(); _mediaCtrl = null; dis = true; } } catch (Exception ex) { Debug.WriteLine(ex); } if (_filterGraph != null) { Marshal.ReleaseComObject(_filterGraph); _filterGraph = null; } GC.Collect(); } int ISampleGrabberCB.SampleCB(double sampleTime, IMediaSample pSample) { Marshal.ReleaseComObject(pSample); return 0; } int ISampleGrabberCB.BufferCB(double sampleTime, IntPtr pBuffer, int bufferLen) { if (Form1.ExtractAutomatic == true) { using (var bitmap = new Bitmap(_width, _height, _width * 3, PixelFormat.Format24bppRgb, pBuffer)) { if (!this.Secondpass) { long[] HistogramValues = Form1.GetHistogram(bitmap); long t = Form1.GetTopLumAmount(HistogramValues, 1000); Form1.averagesTest.Add(t); } else { //this is the changed part if (_frameId > 0) { if (Form1.averagesTest[_frameId] / 1000.0 - Form1.averagesTest[_frameId - 1] / 1000.0 > 150.0) { count = 6; } if (count > 0) { bitmap.RotateFlip(RotateFlipType.Rotate180FlipX); bitmap.Save(Path.Combine(_outFolder, _frameId.ToString("D6") + ".bmp")); count --; } } } _frameId++; //let only report each 100 frames for performance if (_frameId % 100 == 0) OnProgressChanged(_frameId); } } else { using (var bitmap = new Bitmap(_width, _height, _width * 3, PixelFormat.Format24bppRgb, pBuffer)) { if (!this.Secondpass) { //get avg double average = GetAveragePixelValue(bitmap); if (AveragesList == null) AveragesList = new List<double>(); //save avg AveragesList.Add(average); //***************************\\ // for (int i = 0; i < (int)framesCounts(); i++) // { // get histogram values long[] HistogramValues = Form1.GetHistogram(bitmap); if (histogramValuesList == null) histogramValuesList = new List<long>(256); histogramValuesList.AddRange(HistogramValues); //***************************\\ //} } else { if (FramesToSave != null && FramesToSave.Contains(_frameId)) { bitmap.RotateFlip(RotateFlipType.Rotate180FlipX); bitmap.Save(Path.Combine(_outFolder, _frameId.ToString("D6") + ".bmp")); // get histogram values long[] HistogramValues = Form1.GetHistogram(bitmap); if (histogramValuesList == null) histogramValuesList = new List<long>(256); histogramValuesList.AddRange(HistogramValues); using (BinaryWriter binWriter = new BinaryWriter(File.Open(fileName, FileMode.Create))) { for (int i = 0; i < histogramValuesList.Count; i++) { binWriter.Write(histogramValuesList[(int)i]); } binWriter.Close(); } } } _frameId++; //let only report each 100 frames for performance if (_frameId % 100 == 0) OnProgressChanged(_frameId); } } return 0; } /* int ISampleGrabberCB.SampleCB(double sampleTime, IMediaSample pSample) { Marshal.ReleaseComObject(pSample); return 0; } int ISampleGrabberCB.BufferCB(double sampleTime, IntPtr pBuffer, int bufferLen) { using (var bitmap = new Bitmap(_width, _height, _width * 3, PixelFormat.Format24bppRgb, pBuffer)) { if (!this.Secondpass) { //get avg double average = GetAveragePixelValue(bitmap); if (AveragesList == null) AveragesList = new List<double>(); //save avg AveragesList.Add(average); //***************************\\ // for (int i = 0; i < (int)framesCounts(); i++) // { // get histogram values long[] HistogramValues = Form1.GetHistogram(bitmap); if (histogramValuesList == null) histogramValuesList = new List<long>(256); histogramValuesList.AddRange(HistogramValues); long t = Form1.GetTopLumAmount(HistogramValues, 1000); //***************************\\ Form1.averagesTest.Add(t); // to add this list to a text file or binary file and read the averages from the file when its is Secondpass !!!!! //} } else { if (FramesToSave != null && FramesToSave.Contains(_frameId)) { bitmap.RotateFlip(RotateFlipType.Rotate180FlipX); bitmap.Save(Path.Combine(_outFolder, _frameId.ToString("D6") + ".bmp")); // get histogram values long[] HistogramValues = Form1.GetHistogram(bitmap); if (histogramValuesList == null) histogramValuesList = new List<long>(256); histogramValuesList.AddRange(HistogramValues); using (BinaryWriter binWriter = new BinaryWriter(File.Open(fileName, FileMode.Create))) { for (int i = 0; i < histogramValuesList.Count; i++) { binWriter.Write(histogramValuesList[(int)i]); } binWriter.Close(); } } for (int x = 1; x < Form1.averagesTest.Count; x++) { double fff = Form1.averagesTest[x] / 1000.0 - Form1.averagesTest[x - 1] / 1000.0; if (Form1.averagesTest[x] / 1000.0 - Form1.averagesTest[x - 1] / 1000.0 > 180.0) { bitmap.RotateFlip(RotateFlipType.Rotate180FlipX); bitmap.Save(Path.Combine(_outFolder, _frameId.ToString("D6") + ".bmp")); _frameId++; } } } _frameId++; //let only report each 100 frames for performance if (_frameId % 100 == 0) OnProgressChanged(_frameId); } return 0; }*/ private unsafe double GetAveragePixelValue(Bitmap bmp) { BitmapData bmData = null; try { bmData = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb); int stride = bmData.Stride; IntPtr scan0 = bmData.Scan0; int w = bmData.Width; int h = bmData.Height; double sum = 0; long pixels = bmp.Width * bmp.Height; byte* p = (byte*)scan0.ToPointer(); for (int y = 0; y < h; y++) { p = (byte*)scan0.ToPointer(); p += y * stride; for (int x = 0; x < w; x++) { double i = ((double)p[0] + p[1] + p[2]) / 3.0; sum += i; p += 3; } //no offset incrementation needed when getting //the pointer at the start of each row } bmp.UnlockBits(bmData); double result = sum / (double)pixels; return result; } catch { try { bmp.UnlockBits(bmData); } catch { } } return -1; } } public class FrameCountEventArgs { public long FrameCount { get; set; } } public class ProgressEventArgs { public int FrameID { get; set; } } } I remember i had this codec problem/s before and i installed the codec/'s that were needed but in this case both quick time and windows media player can play the video files so why the application cant detect and find the codec/'s on my computer ? Gspot say that the codec is AVC1 but again wmp and quicktime play the video files no problems. The video files are from my digital camera !

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  • What am I not getting about this abstract class implementation?

    - by Schnapple
    PREFACE: I'm relatively inexperienced in C++ so this very well could be a Day 1 n00b question. I'm working on something whose long term goal is to be portable across multiple operating systems. I have the following files: Utilities.h #include <string> class Utilities { public: Utilities() { }; virtual ~Utilities() { }; virtual std::string ParseString(std::string const& RawString) = 0; }; UtilitiesWin.h (for the Windows class/implementation) #include <string> #include "Utilities.h" class UtilitiesWin : public Utilities { public: UtilitiesWin() { }; virtual ~UtilitiesWin() { }; virtual std::string ParseString(std::string const& RawString); }; UtilitiesWin.cpp #include <string> #include "UtilitiesWin.h" std::string UtilitiesWin::ParseString(std::string const& RawString) { // Magic happens here! // I'll put in a line of code to make it seem valid return ""; } So then elsewhere in my code I have this #include <string> #include "Utilities.h" void SomeProgram::SomeMethod() { Utilities *u = new Utilities(); StringData = u->ParseString(StringData); // StringData defined elsewhere } The compiler (Visual Studio 2008) is dying on the instance declaration c:\somepath\somecode.cpp(3) : error C2259: 'Utilities' : cannot instantiate abstract class due to following members: 'std::string Utilities::ParseString(const std::string &)' : is abstract c:\somepath\utilities.h(9) : see declaration of 'Utilities::ParseString' So in this case what I'm wanting to do is use the abstract class (Utilities) like an interface and have it know to go to the implemented version (UtilitiesWin). Obviously I'm doing something wrong but I'm not sure what. It occurs to me as I'm writing this that there's probably a crucial connection between the UtilitiesWin implementation of the Utilities abstract class that I've missed, but I'm not sure where. I mean, the following works #include <string> #include "UtilitiesWin.h" void SomeProgram::SomeMethod() { Utilities *u = new UtilitiesWin(); StringData = u->ParseString(StringData); // StringData defined elsewhere } but it means I'd have to conditionally go through the different versions later (i.e., UtilitiesMac(), UtilitiesLinux(), etc.) What have I missed here?

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  • EJB failure to update datamodel

    - by Ignacio
    Here my EJB @Entity @Table(name = "modelos") @NamedQueries({ @NamedQuery(name = "Modelos.findAll", query = "SELECT m FROM Modelos m"), @NamedQuery(name = "Modelos.findById", query = "SELECT m FROM Modelos m WHERE m.id = :id"), @NamedQuery(name = "Modelos.findByDescripcion", query = "SELECT m FROM Modelos m WHERE m.descripcion = :descripcion")}) public class Modelos implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Basic(optional = false) @Column(name = "id") private Integer id; @Basic(optional = false) @Column(name = "descripcion") private String descripcion; @OneToMany(cascade = CascadeType.ALL, mappedBy = "idModelo") private Collection produtosCollection; @JoinColumn(name = "id_marca", referencedColumnName = "id") @ManyToOne(optional = false) private Marcas idMarca; public Modelos() { } public Modelos(Integer id) { this.id = id; } public Modelos(Integer id, String descripcion) { this.id = id; this.descripcion = descripcion; } public Modelos(Integer id, Marcas idMarca) { this.id = id; this.idMarca = idMarca; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getDescripcion() { return descripcion; } public void setDescripcion(String descripcion) { this.descripcion = descripcion; } public Collection<Produtos> getProdutosCollection() { return produtosCollection; } public void setProdutosCollection(Collection<Produtos> produtosCollection) { this.produtosCollection = produtosCollection; } public Marcas getIdMarca() { return idMarca; } public void setIdMarca(Marcas idMarca) { this.idMarca = idMarca; } @Override public int hashCode() { int hash = 0; hash += (id != null ? id.hashCode() : 0); return hash; } @Override public boolean equals(Object object) { // TODO: Warning - this method won't work in the case the id fields are not set if (!(object instanceof Modelos)) { return false; } Modelos other = (Modelos) object; if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) { return false; } return true; } @Override public String toString() { return "" + descripcion + ""; } } And the method accesing from the Modelosfacade public List findByMarcas(Marcas idMarca){ return em.createQuery("SELECT id, descripcion FROM Modelos WHERE idMarca = "+idMarca.getId()+"").getResultList(); } And the calling method from the controller public String createByMarcas() { //recreateModel(); items = new ListDataModel(ejbFacade.findByMarcas(current.getIdMarca())); updateCurrentItem(); System.out.println(current.getIdMarca()); return "List"; } I do not understand why I keep falling in an EJB exception.

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  • Delphi / MySql : Problems escaping strings

    - by mawg
    N00b here, having problems escaping strings. I used the QuotedStr() function - shouldn't that be enough. Unfortunately, the string that I am trying to quote is rather messy, but I will post it here in case anyone wants to paste it into WinMerge or KDiff3, etc. I am trying to store an entire Delphi form into the database, rather than into a .DFM file. It has only one field, a TEdit edit box. The debugger shows the form as text as 'object Form1: TScriptForm'#$D#$A' Left = 0'#$D#$A' Top = 0'#$D#$A' Align = alClient'#$D#$A' BorderStyle = bsNone'#$D#$A' ClientHeight = 517'#$D#$A' ClientWidth = 993'#$D#$A' Color = clBtnFace'#$D#$A' Font.Charset = DEFAULT_CHARSET'#$D#$A' Font.Color = clWindowText'#$D#$A' Font.Height = -11'#$D#$A' Font.Name = 'MS Sans Serif''#$D#$A' Font.Style = []'#$D#$A' OldCreateOrder = False'#$D#$A' SaveProps.Strings = ('#$D#$A' 'Visible=False')'#$D#$A' PixelsPerInch = 96'#$D#$A' TextHeight = 13'#$D#$A' object Edit1: TEdit'#$D#$A' Left = 192'#$D#$A' Top = 64'#$D#$A' Width = 121'#$D#$A' Height = 21'#$D#$A' TabOrder = 8'#$D#$A' end'#$D#$A'end'#$D#$A before calling QuotedStr() and ''object Form1: TScriptForm'#$D#$A' Left = 0'#$D#$A' Top = 0'#$D#$A' Align = alClient'#$D#$A' BorderStyle = bsNone'#$D#$A' ClientHeight = 517'#$D#$A' ClientWidth = 993'#$D#$A' Color = clBtnFace'#$D#$A' Font.Charset = DEFAULT_CHARSET'#$D#$A' Font.Color = clWindowText'#$D#$A' Font.Height = -11'#$D#$A' Font.Name = ''MS Sans Serif'''#$D#$A' Font.Style = []'#$D#$A' OldCreateOrder = False'#$D#$A' SaveProps.Strings = ('#$D#$A' ''Visible=False'')'#$D#$A' PixelsPerInch = 96'#$D#$A' TextHeight = 13'#$D#$A' object Edit1: TEdit'#$D#$A' Left = 192'#$D#$A' Top = 64'#$D#$A' Width = 121'#$D#$A' Height = 21'#$D#$A' TabOrder = 8'#$D#$A' end'#$D#$A'end'#$D#$A''' afterwards. The strange thing is that my complete command 'INSERT INTO designerFormDfm(designerFormDfmText) VALUES ("'object Form1: TScriptForm'#$D#$A' Left = 0'#$D#$A' Top = 0'#$D#$A' Align = alClient'#$D#$A' BorderStyle = bsNone'#$D#$A' ClientHeight = 517'#$D#$A' ClientWidth = 993'#$D#$A' Color = clBtnFace'#$D#$A' Font.Charset = DEFAULT_CHARSET'#$D#$A' Font.Color = clWindowText'#$D#$A' Font.Height = -11'#$D#$A' Font.Name = ''MS Sans Serif'''#$D#$A' Font.Style = []'#$D#$A' OldCreateOrder = False'#$D#$A' SaveProps.Strings = ('#$D#$A' ''Visible=False'')'#$D#$A' PixelsPerInch = 96'#$D#$A' TextHeight = 13'#$D#$A' object Edit1: TEdit'#$D#$A' Left = 192'#$D#$A' Top = 64'#$D#$A' Width = 121'#$D#$A' Height = 21'#$D#$A' TabOrder = 8'#$D#$A' end'#$D#$A'end'#$D#$A''");' executes in a MySql console, but not from Delphi, where I pass that command as parameter command to a function which ADOCommand.CommandText := command; ADOCommand.CommandType := cmdText; ADOCommand.Execute(); I can only assume that I am having problems escpaing sequences which contain single quotes (and QuotedStr() doesn't seem to escape backslahes(?!)) What am I doing that is obviously, glaringly wrong?

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  • ArithmeticException thrown during BigDecimal.divide

    - by polygenelubricants
    I thought java.math.BigDecimal is supposed to be The Answer™ to the need of performing infinite precision arithmetic with decimal numbers. Consider the following snippet: import java.math.BigDecimal; //... final BigDecimal one = BigDecimal.ONE; final BigDecimal three = BigDecimal.valueOf(3); final BigDecimal third = one.divide(three); assert third.multiply(three).equals(one); // this should pass, right? I expect the assert to pass, but in fact the execution doesn't even get there: one.divide(three) causes ArithmeticException to be thrown! Exception in thread "main" java.lang.ArithmeticException: Non-terminating decimal expansion; no exact representable decimal result. at java.math.BigDecimal.divide It turns out that this behavior is explicitly documented in the API: In the case of divide, the exact quotient could have an infinitely long decimal expansion; for example, 1 divided by 3. If the quotient has a non-terminating decimal expansion and the operation is specified to return an exact result, an ArithmeticException is thrown. Otherwise, the exact result of the division is returned, as done for other operations. Browsing around the API further, one finds that in fact there are various overloads of divide that performs inexact division, i.e.: final BigDecimal third = one.divide(three, 33, RoundingMode.DOWN); System.out.println(three.multiply(third)); // prints "0.999999999999999999999999999999999" Of course, the obvious question now is "What's the point???". I thought BigDecimal is the solution when we need exact arithmetic, e.g. for financial calculations. If we can't even divide exactly, then how useful can this be? Does it actually serve a general purpose, or is it only useful in a very niche application where you fortunately just don't need to divide at all? If this is not the right answer, what CAN we use for exact division in financial calculation? (I mean, I don't have a finance major, but they still use division, right???).

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  • Rails. Putting update logic in your migrations

    - by Daniel Abrahamsson
    A couple of times I've been in the situation where I've wanted to refactor the design of some model and have ended up putting update logic in migrations. However, as far as I've understood, this is not good practice (especially since you are encouraged to use your schema file for deployment, and not your migrations). How do you deal with these kind of problems? To clearify what I mean, say I have a User model. Since I thought there would only be two kinds of users, namely a "normal" user and an administrator, I chose to use a simple boolean field telling whether the user was an adminstrator or not. However, after I while I figured I needed some third kind of user, perhaps a moderator or something similar. In this case I add a UserType model (and the corresponding migration), and a second migration for removing the "admin" flag from the user table. And here comes the problem. In the "add_user_type_to_users" migration I have to map the admin flag value to a user type. Additionally, in order to do this, the user types have to exist, meaning I can not use the seeds file, but rather create the user types in the migration (also considered bad practice). Here comes some fictional code representing the situation: class CreateUserTypes < ActiveRecord::Migration def self.up create_table :user_types do |t| t.string :name, :nil => false, :unique => true end #Create basic types (can not put in seed, because of future migration dependency) UserType.create!(:name => "BASIC") UserType.create!(:name => "MODERATOR") UserType.create!(:name => "ADMINISTRATOR") end def self.down drop_table :user_types end end class AddTypeIdToUsers < ActiveRecord::Migration def self.up add_column :users, :type_id, :integer #Determine type via the admin flag basic = UserType.find_by_name("BASIC") admin = UserType.find_by_name("ADMINISTRATOR") User.all.each {|u| u.update_attribute(:type_id, (u.admin?) ? admin.id : basic.id)} #Remove the admin flag remove_column :users, :admin #Add foreign key execute "alter table users add constraint fk_user_type_id foreign key (type_id) references user_types (id)" end def self.down #Re-add the admin flag add_column :users, :admin, :boolean, :default => false #Reset the admin flag (this is the problematic update code) admin = UserType.find_by_name("ADMINISTRATOR") execute "update users set admin=true where type_id=#{admin.id}" #Remove foreign key constraint execute "alter table users drop foreign key fk_user_type_id" #Drop the type_id column remove_column :users, :type_id end end As you can see there are two problematic parts. First the row creation part in the first model, which is necessary if I would like to run all migrations in a row, then the "update" part in the second migration that maps the "admin" column to the "type_id" column. Any advice?

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  • Checking if an int is prime more efficiently

    - by SipSop
    I recently was part of a small java programming competition at my school. My partner and I have just finished our first pure oop class and most of the questions were out of our league so we settled on this one (and I am paraphrasing somewhat): "given an input integer n return the next int that is prime and its reverse is also prime for example if n = 18 your program should print 31" because 31 and 13 are both prime. Your .class file would then have a test case of all the possible numbers from 1-2,000,000,000 passed to it and it had to return the correct answer within 10 seconds to be considered valid. We found a solution but with larger test cases it would take longer than 10 seconds. I am fairly certain there is a way to move the range of looping from n,..2,000,000,000 down as the likely hood of needing to loop that far when n is a low number is small, but either way we broke the loop when a number is prime under both conditions is found. At first we were looping from 2,..n no matter how large it was then i remembered the rule about only looping to the square root of n. Any suggestions on how to make my program more efficient? I have had no classes dealing with complexity analysis of algorithms. Here is our attempt. public class P3 { public static void main(String[] args){ long loop = 2000000000; long n = Integer.parseInt(args[0]); for(long i = n; i<loop; i++) { String s = i +""; String r = ""; for(int j = s.length()-1; j>=0; j--) r = r + s.charAt(j); if(prime(i) && prime(Long.parseLong(r))) { System.out.println(i); break; } } System.out.println("#"); } public static boolean prime(long p){ for(int i = 2; i<(int)Math.sqrt(p); i++) { if(p%i==0) return false; } return true; } } ps sorry if i did the formatting for code wrong this is my first time posting here. Also the output had to have a '#' after each line thats what the line after the loop is about Thanks for any help you guys offer!!!

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  • mulformed Farsi characters on AWT

    - by jlover2010
    Hi As i started programming by jdk6, i had no problem in text components neither in awt nor in swing. But for labels or titles of awt components, yes : I couldn't have Farsi characters displayable on AWTs just as simple as Swing by typing them into the source code. lets check this SSCCE : import javax.swing.*; import java.awt.*; import java.io.*; import java.util.Properties; public class EmptyFarsiCharsOnAWT extends JFrame{ public EmptyFarsiCharsOnAWT() { super("????"); setDefaultCloseOperation(3); setVisible(rootPaneCheckingEnabled); } public static void main(String[] args) throws AWTException, IOException { JFrame jFrame = new EmptyFarsiCharsOnAWT(); MenuItem show ; // approach 1 = HardCoding : /* show = new MenuItem("\u0646\u0645\u0627\u06cc\u0634"); * */ // approach 2 = using simple utf-8 saved text file : /* BufferedReader in = new BufferedReader(new FileReader("farsiLabels.txt")); String showLabel = in.readLine(); in.close(); show = new MenuItem(showLabel); * */ // approach 3 = using properties file : FileReader in = new FileReader("farsiLabels.properties"); Properties farsiLabels = new Properties(); farsiLabels.load(in); show = new MenuItem(farsiLabels.getProperty("tray.show")); PopupMenu popUp = new PopupMenu(); popUp.add(show); // creating Tray object Image iconIamge = Toolkit.getDefaultToolkit().getImage("greenIcon.png"); TrayIcon trayIcon = new TrayIcon(iconIamge, null, popUp); SystemTray tray = SystemTray.getSystemTray(); tray.add(trayIcon); jFrame.setIconImage(iconIamge); } } Yes, i know each of three approaches in source code does right when you may test it from IDE , but if you make a JAR contains just this class (and its resources) by means of NetBeans project clean&build ,you won't see the expected characters and will just get EMPTY/BLANK SQUARES ! Unfortunately, opposed to other situations i encountered before, here there is no way to avoid using awt and make use of Swing in this case. And this was just an SSCCE i made to show the problem and my recent (also first) application suffers from this subject. And i think should have to let you know I posted this question a while ago in SDN and "the Java Ranch" forums and other native forums and still I'm watching... By the way i am using latest version of Netbeans IDE... I will be so grateful if anybody has a solution to this damn AWT components never rendered any Farsi character for me... Thanks in advance

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  • Failed to obtain JDBC Driver for MySQL under Tomcat environment

    - by Michael Mao
    Hi all: I've been trying to obtain the Driver class for JDBC connection to MySQL. The workstation is running on Linux, Fedora 10. I have manually set up the classpath variable for Java by CLI like this: bash-3.2$ echo $CLASSPATH /home/cmao/public_html/jsp/mysql-connector-java-5.1.12-bin.jar This shows that I've added the lastest mysql connection jar archive to my CLASSPATH variable. I've created a test JSP page which can be found here And source code for this page is: <%@page language="java"%> <%@page import="java.sql.*"%> <%@page import="java.util.*"%> <html> <head> <title>UTS JDBC MySQL connection test page</title> </head> <body> <% Connection con = null; out.print("Java version is : " + System.getProperty("java.version") + "<br />"); out.print("Tomcat version is : " + application.getServerInfo() + "<br />"); out.print("Servlet version is: " + application.getMajorVersion() + "<br />"); out.print("JSP version is : " + JspFactory.getDefaultFactory().getEngineInfo().getSpecificationVersion() +"<br />"); //out.print("Java classpath is : " + System.getProperty("java.class.path")+ "<br />"); //out.print("JSP classpath is : " + appliaction.getAttribute("org.apache.catalina.jsp_classpath") + "<br />"); //out.print("Tomcat classpath is : " + System.getProperty("org.apache.tomcat.common.classpath") + "<br />"); try { Class c = Class.forName("com.mysql.jdbc.Driver"); } catch(Exception e) { out.println("Error! Failed to obtain JDBC driver for MySQL... Missing class \"com.mysql.jdbc.Driver\"<br />"); } %> </body> </html> None of those commented out line would work, various Jsper Expetions would be thrown. You can check those Error pages from the following links: classpath Error page catalina Error page tomcat Error page It seems, from my limited knowledge of JSP and Servlet, the Tomcat environment "ignores" my Java CLASSPATH? In which case I cannot configure the MySQL JDBC package to let my Servlets(a JSP is but a Servlet anyway) work. I am not sure how to fix this issue. would it be better if I use an IDE like Eclipse or NetBeans and create a real Java "web app" so that everything can be "self-configured" by the usage of a web.config XML configuration file? So that I can certainly bypass this Tomcat environment restriction? Many thanks for the suggestions in advance.

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  • What Amazon S3 .NET Library is most useful and efficient?

    - by Geo
    There are two main open source .net Amazon S3 libraries. Three Sharp LitS3 I am currently using LitS3 in our MVC demo project, but there is some criticism about it. Has anyone here used both libraries so they can give an objective point of view. Below some sample calls using LitS3: On demo controller: private S3Service s3 = new S3Service() { AccessKeyID = "Thekey", SecretAccessKey = "testing" }; public ActionResult Index() { ViewData["Message"] = "Welcome to ASP.NET MVC!"; return View("Index",s3.GetAllBuckets()); } On demo view: <% foreach (var item in Model) { %> <p> <%= Html.Encode(item.Name) %> </p> <% } %> EDIT 1: Since I have to keep moving and there is no clear indication of what library is more effective and kept more up to date, I have implemented a repository pattern with an interface that will allow me to change library if I need to in the future. Below is a section of the S3Repository that I have created and will let me change libraries in case I need to: using LitS3; namespace S3Helper.Models { public class S3Repository : IS3Repository { private S3Service _repository; #region IS3Repository Members public IQueryable<Bucket> FindAllBuckets() { return _repository.GetAllBuckets().AsQueryable(); } public IQueryable<ListEntry> FindAllObjects(string BucketName) { return _repository.ListAllObjects(BucketName).AsQueryable(); } #endregion If you have any information about this question please let me know in a comment, and I will get back and edit the question. EDIT 2: Since this question is not getting attention, I integrated both libraries in my web app to see the differences in design, I know this is probably a waist of time, but I really want a good long run solution. Below you will see two samples of the same action with the two libraries, maybe this will motivate some of you to let me know your thoughts. WITH THREE SHARP LIBRARY: public IQueryable<T> FindAllBuckets<T>() { List<string> list = new List<string>(); using (BucketListRequest request = new BucketListRequest(null)) using (BucketListResponse response = service.BucketList(request)) { XmlDocument bucketXml = response.StreamResponseToXmlDocument(); XmlNodeList buckets = bucketXml.SelectNodes("//*[local-name()='Name']"); foreach (XmlNode bucket in buckets) { list.Add(bucket.InnerXml); } } return list.Cast<T>().AsQueryable(); } WITH LITS3 LIBRARY: public IQueryable<T> FindAllBuckets<T>() { return _repository.GetAllBuckets() .Cast<T>() .AsQueryable(); }

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  • ASP.NET MVC 2 AJAX dilemma: Lose Models concept or create unmanageable JavaScript

    - by Slightly Frustrated
    Hi, Ok, let's assume we are working with ASP.NET MVC 2 (latest and greatest preview) and we want to create AJAX user interface with jQuery. So what are our real options here? Option 1 - Pass Json from the Controller to the view, and then the view submits Json back to the controller. This means (in the order given): User opens some View (let's say - /Invoices/January) which has to visualize a list of data (e.g. <IEnumerable<X.Y.Z.Models.Invoice>>) Controller retrieves the Model from the repository (assuming we are using repository pattern). Controller creates a new instance of a class which we will serialize to Json. The reasaon we do this, is because the model may not be serializable (circular reference ftl) Controller populates the soon-to-be-serialized class with data Controller serializes the class to Json and passes it the view. User does some change and submits the 'form' The View submits back Json to the controller The Controller now must 'manually' validate the input, because the Json passed does not bind to a Model See, if our View is communicating to the controller via Json, we lose the Model validation, which IMHO is incredible disadvantage. In this case, forget about data annotations and stuff. Option 2 - Ok, the alternative of the first approach is to pass the Models to the Views, which is the default behavior in the template when you start a new project. We pass a strong typed model to the view The view renders the appropriate html and javascript, sticking to the model property names. This is important! The user submits the form. If we stick to the model names, when we .serialize() the form and submit it to the controller it will map to a model. There is no Json mapping. The submitted form directly binds to a strongly typed model, hence, we can use the model validation. E.g. we keep the business logic where it should be. Problem with this approach is, if we refactor some of the Models (change property names, types, etc), the javascript we wrote would become invalid. We will have to manually refactor the scripting and hope we don't miss something. There is no way you can test it either. Ok, the question is - how to write an AJAX front end, which keeps the business logic validation in the model (e.g. controller passes and receives a Model type), but in the same time doesn't screw up the javascript and html when we refactor the model?

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  • Killing Mysql prcoesses staying in sleep command.

    - by Shino88
    Hey I am connecting a MYSQL database through hibernate and i seem to have processes that are not being killed after they are finished in the session. I have called flush and close on each session but when i check the server the last processes are still there with a sleep command. This is a new problem which i am having and was not the case yesterday. Is there any way i can ensure the killng of theses processes when i am done with a session. Below is an example of one of my classes. public JSONObject check() { //creates a new session needed to add elements to a database Session session = null; //holds the result of the check in the database JSONObject check = new JSONObject(); try{ //creates a new session needed to add elements to a database SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory(); session = sessionFactory.openSession(); if (justusername){ //query created to select a username from user table String hquery = "Select username from User user Where username = ? "; //query created Query query = session.createQuery(hquery); //sets the username of the query the values JSONObject contents query.setString(0, username); // executes query and adds username string variable String user = (String) query.uniqueResult(); //checks to see if result is found (null if not found) if (user == null) { //adds false to Jobject if not found check.put("indatabase", "false"); } else { check.put("indatabase", "true"); } //adds check to Jobject to say just to check username check.put("justusername", true); } else { //query created to select a username and password from user table String hquery = "Select username from User user Where username = :user and password = :pass "; Query query = session.createQuery(hquery); query.setString("user", username); query.setString("pass", password); String user = (String) query.uniqueResult(); if(user ==null) { check.put("indatabase", false); } else { check.put("indatabase", true); } check.put("justusername", false); } }catch(Exception e){ System.out.println(e.getMessage()); //logg.log(Level.WARNING, " Exception", e.getMessage()); }finally{ // Actual contact insertion will happen at this step session.flush(); session.close(); } //returns Jobject return check; }

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  • ASP.NET- forcing child/container events to fire before parent onload?

    - by Hans Gruber
    I'm working on a questionnaire type application in which questions are stored in a database. Therefore, I create my controls dynamically on every Page.OnLoad. This works like a charm and ViewState is persisted between postbacks because I ensure that my dynamic controls always have the same generated Control.ID. In addition to the user control that dynamically populates the questions, my questionnaire page also contains a 'Status' section (also encapsulated by a user control) which represents the status of the questionnaire (choices are 'Complete', 'Started' or 'In Progress'). If the user changes the status of questionnaire (i.e. from 'In Progress' to 'Complete'), I need to postback to the server because the contents of the dynamic portion of the questionnaire depend on the selected status. Some questions are always present regardless of status, and yet others may not be present at all for the selected status. The point is, when the status changes, I have to postback to the page and render the right set of questions. Additionally, I need to preserve any user entered values for those questions which are 'always available'. However, due to the page life cycle in ASP.NET, the 'Status' user control's OnLoad, which contains the correct status needed to load the right questions from the DB, doesn't get executed until after the 'dynamic questions' user control has already been populated (with the wrong/stale values). To get around this, I raise an event from my 'Status' user control to the main page to indicate that the Status has changed. The main page then raises an event on the 'dynamic questions' user control. Since by the time this event bubbles up, the 'dynamic questions' user control has already loaded the 'wrong' questions from the DB, it first calls Controls.Clear. It then happily uses the new status to query the database for the 'correct' questions and does a Control.Add() on each. FYI, Control.IDs are consistent across postbacks. This solution works...sorta. The correct set of questions for the selected status do get rendered; however ViewState is getting lost for those 'always available' questions. I'm guessing this is because the 'dynamic questions' user control calls Controls.Clear when responding to the status changed event. This must somehow kill the association between ViewState and my dynamic controls, even though the Control.ID are consistent. This seems like such a common requirement, I'm virtually certain there is a better, cleaner and less error prone approach to accomplish this. In case its not plain obvious, I haven't been able to grok the ASP.NET page life-cycle despite working with it for the last year. Any help is much appreciated!

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  • Multiline editable textarea in SVG

    - by Timo
    I'm trying to implement multiline editable textfield in SVG. I have the following code in http://jsfiddle.net/ca4d3/ : <svg width="1000" height="1000" overflow="scroll"> <g transform="rotate(5)"> <rect width="300" height="400" fill="#22DD22" fill-opacity="0.5"/> </g> <foreignObject x="10" y="10" overflow="visible" width="10000" height="10000" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"> <p style="display:table-cell;padding:10px;border:1px solid red; background-color:white;opacity:0.5;font-family:Verdana; font-size:20px;white-space: pre; word-wrap: normal; overflow: visible; overflow-y: visible; overflow-x:visible;" contentEditable="true" xmlns="http://www.w3.org/1999/xhtml"> Write here some text. Be smart and select some word. If you wanna be really COOL, paste here something cool! </p> </foreignObject> </svg> In newest Chrome, Safari and Firefox the code works in some way, but in Opera and IE 9 not. The goal is that: 0) Works in newest Chrome, Safari, Firefox, Opera and IE and if ever possible in some pads. 1) White-spaces are preserved and text wraps only on newline char (works in Chrome, Safari and Firefox, but not in Opera and IE 9 *). 2) The textfield is editable (in the same reliable and stabile way as textareas and contenteditable p elements in html) and height and width is expanded to fit text (works in Chrome, Safari and Firefox, but not in Opera and IE 9 *). 3) Texfield can be transformed (rotated, skewed, translated) while maintaining text editability (Tested rotation, but not work in any browser *). EDIT: Foreignobject rotation works on Firefox 15.0.1, but not in Safari 5.1.7 (6534.57.2), Chrome 22.0.1229.79, Opera 12.02, IE 9. Tested on Mac OS X 10.6.8. 4) Textfield can be clipped and masked while not necessarily maintaining text editability (not yet tested). *) using above code These all can be achieved using Flash, but Flash has so severe problems that it is not suitable for my purposes (after every little change in code, all have to be compiled again using Flex, which is slow, font size has limits, tracking technique is pixeloriented, not relative to em size etc.) and there still are differences across platforms. And I want to give a try to SVG! GUESTION: Can I achieve my goals 0-4 with current SVG support in browsers? Is coming SVG 2.0 for some help in this case? EDIT: Changed display:table to display:table-cell (and added new jsfiddle), because display:table made the field to loses focus when pressed arrow-up on first text row.

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  • IQueryable and lazy loading

    - by Nelson
    I'm having a hard time determining the best way to handle this... With Entity Framework (and L2S), LINQ queries return IQueryable. I have read various opinions on whether the DAL/BLL should return IQueryable, IEnumerable or IList. Assuming we go with IList, then the query is run immediately and that control is not passed on to the next layer. This makes it easier to unit test, etc. You lose the ability to refine the query at higher levels, but you could simply create another method that allows you to refine the query and still return IList. And there are many more pros/cons. So far so good. Now comes Entity Framework and lazy loading. I am using POCO objects with proxies in .NET 4/VS 2010. In the presentation layer I do: foreach (Order order in bll.GetOrders()) { foreach (OrderLine orderLine in order.OrderLines) { // Do something } } In this case, GetOrders() returns IList so it executes immediately before returning to the PL. But in the next foreach, you have lazy loading which executes multiple SQL queries as it gets all the OrderLines. So basically, the PL is running SQL queries "on demand" in the wrong layer. Is there any sensible way to avoid this? I could turn lazy loading off, but then what's the point of having this "feature" that everyone was complaining EF1 didn't have? And I'll admit it is very useful in many scenarios. So I see several options: Somehow remove all associations in the entities and add methods to return them. This goes against the default EF behavior/code generation and makes it harder to do some composite (multiple entity) LINQ queries. It seems like a step backwards. I vote no. If we have lazy loading anyway which makes it hard to unit test, then go all the way and return IQueryable. You'll have more control farther up the layers. I still don't think this is a good option because IQueryable ties you to L2S, L2E, or your own full implementation of IQueryable. Lazy loading may run queries "on demand", but doesn't tie you to any specific interface. I vote no. Turn off lazy loading. You'll have to handle your associations manually. This could be with eager loading's .Include(). I vote yes in some specific cases. Keep IList and lazy loading. I vote yes in many cases, only due to the troubles with the others. Any other options or suggestions? I haven't found an option that really convinces me.

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  • Issues with LINQ (to Entity) [adding records]

    - by Mario
    I am using LINQ to Entity in a project, where I pull a bunch of data (from the database) and organize it into a bunch of objects and save those to the database. I have not had problems writing to the db before using LINQ to Entity, but I have run into a snag with this particular one. Here's the error I get (this is the "InnerException", the exception itself is useless!): New transaction is not allowed because there are other threads running in the session. I have seen that before, when I was trying to save my changes inside a loop. In this case, the loop finishes, and it tries to make that call, only to give me the exception. Here's the current code: try { //finalResult is a list of the keys to match on for the records being pulled foreach (int i in finalResult) { var queryEff = (from eff in dbMRI.MemberEligibility where eff.Member_Key == i && eff.EffDate >= DateTime.Now select eff.EffDate).Min(); if (queryEff != null) { //Add a record to the Process table Process prRecord = new Process(); prRecord.GroupData = qa; prRecord.Member_Key = i; prRecord.ProcessDate = DateTime.Now; prRecord.RecordType = "F"; prRecord.UsernameMarkedBy = "Autocard"; prRecord.GroupsId = qa.GroupsID; prRecord.Quantity = 2; prRecord.EffectiveDate = queryEff; dbMRI.AddObject("Process", prRecord); } } dbMRI.SaveChanges(); //<-- Crashes here foreach (int i in finalResult) { var queryProc = from pro in dbMRI.Process where pro.Member_Key == i && pro.UsernameMarkedBy == "Autocard" select pro; foreach (var qp in queryProc) { Audit aud = new Audit(); aud.Member_Key = i; aud.ProcessId = qp.ProcessId; aud.MarkDate = DateTime.Now; aud.MarkedByUsername = "Autocard"; aud.GroupData = qa; dbMRI.AddObject("Audit", aud); } } dbMRI.SaveChanges(); //<-- AND here (if the first one is commented out) } catch (Exception e) { //Do Something here } Basically, I need it to insert a record, get the identity for that inserted record and insert a record into another table with the identity from the first record. Given some other constraints, it is not possible to create a FK relationship between the two (I've tried, but some other parts of the app won't allow it, AND my DBA team for whatever reason hates FK's, but that's for a different topic :)) Any ideas what might be causing this? Thank!

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