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• PayPal sandbox Buy Now Problem

  - by Tushar Ahirrao

  Hi , I have paypal sandbox test account. I want to create a 'buy Now' button. I am trying it with GWT. But its even not working with simple HTML form. It displays a 'Buy Now' button on HTML page and after clicking on it redirects to PayPal site. Where it ask to login to buy product but after that it goes on displying message: The email address or password you have entered does not match our records. Please try again. I am using buyer user to purchase product. I am pretty sure about the username and password. Providing here the simple HTML form which I am trying: <form action="https://www.paypal.com/cgi-bin/webscr" method="post" id="payPalForm"> <input type="hidden" name="item_number" value="1"> <input type="hidden" name="cmd" value="_xclick"> <input type="hidden" name="no_note" value="1"> <input type="hidden" name="business" value="[email protected]"> <input type="hidden" name="lc" value="US"> <input type="hidden" name="button_subtype" value="services"> <input type="hidden" name="cn" value="Add special instructions to the seller"> <input type="hidden" name="no_shipping" value="2"> <input type="hidden" name="rm" value="1"> <input type="hidden" name="bn" value="PP-BuyNowBF:btn_paynow_SM.gif:NonHosted"> <input type="hidden" name="variables" value="http://google.com"> <input type="hidden" name="cancel_return" value="http://google.com"> <input type="hidden" name="notify_url" value="http://google.com"> <input type="hidden" name="return" value="http://freelanceswitch.com/payment-complete /"> <input type="hidden" name="currency_code" value="USD"> <input name="item_name" type="hidden" value="Deal Name"> <input name="amount" type="hidden" value="500"> <input type="submit" name="Submit" value="Submit"> </form> Please advice. Thank you.

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• Andorid: the keyboard appeares when the app is started

  - by Briesanji

  I have coded an Android application composed by a LinearLayout(with an editbox and a button) and a ScrollView(with a LinearLayout that contains a TextView). When the app is started the keyboard pops up immediatly and I don't want this to happen. Have you got some advice?? THIS IS MY LAYOUT : <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="com.example.b2875.Messaggi$PlaceholderFragment" > <LinearLayout android:layout_width="fill_parent" android:layout_height="70dp" android:layout_marginTop="650dp" > <EditText android:id="@+id/ScriviMessaggio" android:layout_width="332dp" android:layout_height="71dp" android:ems="10" android:hint="@string/scriviMessaggio" /> <Button android:id="@+id/invia" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/invia" /> </LinearLayout> <ScrollView android:id="@+id/scrollView1" android:scrollbarAlwaysDrawVerticalTrack="true" android:layout_width="fill_parent" android:layout_height="600dp" android:focusable="true" android:focusableInTouchMode="true" > <LinearLayout android:id="@+id/linearVertical" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical" > <TextView android:id="@+id/AreaMessaggi" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/messaggi" /> </LinearLayout> </ScrollView> </RelativeLayout> MY MANIFEST IS THIS: <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.b2875" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="19" /> <uses-permission android:name="android.permission.INTERNET"/> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:windowSoftInputMode="stateHidden" android:name="com.example.b2875.Messaggi" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>

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• How can I position some divs inside an unordered list so they line up with the root element of the l

  - by Ronedog

  I want to position all the divs to line up to the left on the same x coordinate so it looks nice. Notice the picture below, how based on the number of nested categories the div (and its contents) show up at slightly different x coordinates. I need to have the div's line up at exactly the same x coordinate no matter how deeply nested. Note, the bottom most category always has a div for the content, but that div has to be situated inside the last < li . I am using an unordered list to display the menu and thought the best solution would be to grab the root category (Cat 2, and mCat1) and obtain their left offset using jquery, then simply use that value to update the positioning of the div...but I couldn't seem to get it to work just right. I would appreciate any advice or help that you are willing to give. Heres the HTML <ul id="nav> <li>Cat 2 <ul> <li>sub cat2</li> </ul> </li> <li>mCat1 <ul> <li>Subcat A <ul> <li>Subcat A.1 <ul> <li>Annie</li> </ul> </li> </ul> </li> </ul> </li> </ul> Heres some jquery I tried (I have do insert the div inside this .each() loop in order to retrieve some values, but basically, this selector is grabbing the last < li in the menu tree and placing a div after it and that is the div that I want to position. the 245 value was something I was playing around with to see how I could get things to line up, and I know its out of wack, but the problem is still the same no matter what I do: $("#nav li:not(:has(li))").each(function () { var self = $(this); var position = self.offset(); var xLeft = Math.round(position.left)- 245; console.log("xLeft:", xLeft ); self.after( '<div id="' + self.attr('p_node') + '_p_cont_div" class="property_position" style="display:none; left:' + xLeft + 'px;" /> ' ); }); Heres the css: .property_position{ float:left; position: relative; top: 0px; padding-top:5px; padding-bottom:10px; }

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• Java: CSV file read & write.

  - by battousai622

  Im reading in 2 csv file: store_inventory & new_acquisitions... I want to be able to compare the store_inventory csv file with new_acquisitions. 1) If the item names match just update the quantity in store_inventory. 2) If new_acquisitions has a new item that does not exist in store_inventory, then add it to the store_inventory. Heres what i have so far but its not very good. I added comments where i need to add taks 1) & 2). Any advice or code would be great, thanks. File new_acq = new File("/src/test/new_acquisitions.csv"); Scanner acq_scan = null; try { acq_scan = new Scanner(new_acq); } catch (FileNotFoundException ex) { Logger.getLogger(mainpage.class.getName()).log(Level.SEVERE, null, ex); } String itemName; int quantity; Double cost; Double price; File store_inv = new File("/src/test/store_inventory.csv"); Scanner invscan = null; try { invscan = new Scanner(store_inv); } catch (FileNotFoundException ex) { Logger.getLogger(mainpage.class.getName()).log(Level.SEVERE, null, ex); } String itemNameInv; int quantityInv; Double costInv; Double priceInv; while (acq_scan.hasNext()) { String line = acq_scan.nextLine(); if (line.charAt(0) == '#') { continue; } String[] split = line.split(","); itemName = split[0]; quantity = Integer.parseInt(split[1]); cost = Double.parseDouble(split[2]); price = Double.parseDouble(split[3]); while(invscan.hasNext()) { String line2 = invscan.nextLine(); if (line2.charAt(0) == '#') { continue; } String[] split2 = line2.split(","); itemNameInv = split2[0]; quantityInv = Integer.parseInt(split2[1]); costInv = Double.parseDouble(split2[2]); priceInv = Double.parseDouble(split2[3]); if(itemName == itemNameInv) { //update quantity } } //add new entry into csv file } Thanks again for any help. =]

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• Data access pattern, combining push and pull?

  - by andlju

  I need some advice on what kind of pattern(s) I should use for pushing/pulling data into my application. I'm writing a rule-engine that needs to hold quite a large amount of data in-memory in order to be efficient enough. I have some rather conflicting requirements; It is not acceptable for the engine to always have to wait for a full pre-load of all data before it is functional. Only fetching and caching data on-demand will lead to the engine taking too long before it is running quickly enough. An external event can trigger the need for specific parts of the data to be reloaded. Basically, I think I need a combination of pushing and pulling data into the application. A simplified version of my current "pattern" looks like this (in psuedo-C# written in notepad): // This interface is implemented by all classes that needs the data interface IDataSubscriber { void RegisterData(Entity data); } // This interface is implemented by the data access class interface IDataProvider { void EnsureLoaded(Key dataKey); void RegisterSubscriber(IDataSubscriber subscriber); } class MyClassThatNeedsData : IDataSubscriber { IDataProvider _provider; MyClassThatNeedsData(IDataProvider provider) { _provider = provider; _provider.RegisterSubscriber(this); } public void RegisterData(Entity data) { // Save data for later StoreDataInCache(data); } void UseData(Key key) { // Make sure that the data has been stored in cache _provider.EnsureLoaded(key); Entity data = GetDataFromCache(key); } } class MyDataProvider : IDataProvider { List<IDataSubscriber> _subscribers; // Make sure that the data for key has been loaded to all subscribers public void EnsureLoaded(Key key) { if (HasKeyBeenMarkedAsLoaded(key)) return; PublishDataToSubscribers(key); MarkKeyAsLoaded(key); } // Force all subscribers to get a new version of the data for key public void ForceReload(Key key) { PublishDataToSubscribers(key); MarkKeyAsLoaded(key); } void PublishDataToSubscribers(Key key) { Entity data = FetchDataFromStore(key); foreach(var subscriber in _subscribers) { subscriber.RegisterData(data); } } } // This class will be spun off on startup and should make sure that all data is // preloaded as quickly as possible class MyPreloadingThread { IDataProvider _provider; MyPreloadingThread(IDataProvider provider) { _provider = provider; } void RunInBackground() { IEnumerable<Key> allKeys = GetAllKeys(); foreach(var key in allKeys) { _provider.EnsureLoaded(key); } } } I have a feeling though that this is not necessarily the best way of doing this.. Just the fact that explaining it seems to take two pages feels like an indication.. Any ideas? Any patterns out there I should have a look at?

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• FluentNhibernate many-to-many mapping - resolving record is not inserted

  - by Dmitriy Nagirnyak

  Hi, I have a many-to-many mapping defined (only relevant fields included): // MODEL: public class User : IPersistentObject { public User() { Permissions = new HashedSet<Permission>(); } public virtual int Id { get; protected set; } public virtual ISet<Permission> Permissions { get; set; } } public class Permission : IPersistentObject { public Permission() { } public virtual int Id { get; set; } } // MAPPING: public class UserMap : ClassMap<User> { public UserMap() { Id(x => x.Id); HasManyToMany(x => x.Permissions).Cascade.All().AsSet(); } } public class PermissionMap : ClassMap<Permission> { public PermissionMap() { Id(x => x.Id).GeneratedBy.Assigned(); Map(x => x.Description); } } The following test fails as there is no record inserted into User_Permission table: [Test] public void AddingANewUserPrivilegeShouldSaveIt() { var p1 = new Permission { Id = 123, Description = "p1" }; Session.Save(p1); var u = new User { Email = "[email protected]" }; u.Permissions.Add(p1); Session.Save(u); var userId = u.Id; Session.Evict(u); Session.Get<User>(userId).Permissions.Should().Not.Be.Empty(); } The SQL executed is (SQLite): INSERT INTO "Permission" (Description, Id) VALUES (@p0, @p1);@p0 = 'p1', @p1 = 1 INSERT INTO "User" (Email) VALUES (@p0); select last_insert_rowid();@p0 = '[email protected]' SELECT user0_.Id as Id2_0_, user0_.Email as Email2_0_ FROM "User" user0_ WHERE user0_.Id=@p0;@p0 = 1 SELECT permission0_.UserId as UserId1_, permission0_.PermissionId as Permissi2_1_, permission1_.Id as Id4_0_, permission1_.Description as Descript2_4_0_ FROM User_Permissions permission0_ left outer join "Permission" permission1_ on permission0_.PermissionId=permission1_.Id WHERE permission0_.UserId=@p0;@p0 = 1 We can clearly see that there is no record inserted into the User_Permissions table where it should be. Not sure what I am doing wrong and need an advice. So can you please help me to pass this test. Thanks, Dmitriy.

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• Setting UITableViewCell button image values during scrolling

  - by Rob

  I am having an issue where I am trying to save whether a repeat image will show selected or not (it is created as a UIButton on a UITableViewCell created in IB). The issue is that since the cell gets re-used randomly, the image gets reset or set somewhere else after you start scrolling. I've looked all over and the advice was to setup an NSMutableArray to store the button's selection state and I am doing that in an array called checkRepeatState My question is: where do I put the if-then-else statement in the code to where it will actually change the button image based on if the checkRepeatState is set to 0 or 1 for the given cell that is coming back into view? Right now, the if-then-else statement I am using has absolutely no effect on the button image when it comes into view. I'm very confused at this point. Thank you ahead of time for any insight you can give!!! My code is as follows: - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { // set up the cell static NSString *CellIdentifier = @"PlayerCell"; PlayerCell *cell = (PlayerCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (!cell) { [[NSBundle mainBundle] loadNibNamed:@"PlayerNibCells" owner:self options:nil]; cell = tmpCell; self.tmpCell = nil; NSLog(@"Creating a new cell"); } // Display dark and light background in alternate rows -- see tableView:willDisplayCell:forRowAtIndexPath:. cell.useDarkBackground = (indexPath.row % 2 == 0); // Configure the data for the cell. NSDictionary *dataItem = [soundCategories objectAtIndex:indexPath.row]; UILabel *label; label = (UILabel *)[cell viewWithTag:1]; label.text = [dataItem objectForKey:@"AnimalName"]; label = (UILabel *)[cell viewWithTag:2]; label.text = [dataItem objectForKey:@"Description"]; UIImageView *img; img = (UIImageView *)[cell viewWithTag:3]; img.image = [UIImage imageNamed:[dataItem objectForKey:@"Icon"]]; NSInteger row = indexPath.row; NSNumber *checkValue = [checkRepeatState objectAtIndex:row]; NSLog(@"checkValue is %d", [checkValue intValue]); // Reusing cell; make sure it has correct image based on checkRepeatState value UIButton *repeatbutton = (UIButton *)[cell viewWithTag:4]; if ([checkValue intValue] == 1) { NSLog(@"repeatbutton is selected"); [repeatbutton setImage:[UIImage imageNamed:@"repeatselected.png"] forState:UIControlStateSelected]; [repeatbutton setNeedsDisplay]; } else { NSLog(@"repeatbutton is NOT selected"); [repeatbutton setImage:[UIImage imageNamed:@"repeat.png"] forState:UIControlStateNormal]; [repeatbutton setNeedsDisplay]; } cell.accessoryType = UITableViewCellAccessoryNone; return cell; }

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• Update time descriptions every minute using jquery/javascript

  - by Amy Neville

  I have created the following code to update the text contents of all spans like this every minute. There are numerous of these spans on the page which all need to be updated every minute: <span unix="1372263005" class="time_ago">4 minutes ago</span> The code is as follows: window.setInterval(function(){ var unix = $(".time_ago").text(); var now = new Date().getTime(); var amount = 0; var difference = 0; difference = now - parseInt(unix); if (difference < 60) { $(".time_ago").text('<span unix="' + unix + '" class="time_ago">a few seconds ago</span>'); } else if (difference < 120) { $(".time_ago").text('<span unix="' + unix + '" class="time_ago">a minute ago</span>'); } else if (difference < 3600) { amount = floor(difference / 60); $(".time_ago").text('<span unix="' + unix + '" class="time_ago">' + amount + ' minutes ago</span>'); } else if (difference < 7200) { $(".time_ago").text('<span unix="' + unix + '" class="time_ago">an hour ago</span>'); } else if (difference < 86400) { amount = floor(difference / 3600); $(".time_ago").text('<span unix="' + unix + '" class="time_ago">' + amount + ' hours ago</span>'); } else if (difference < 172800) { $(".time_ago").text('<span unix="' + unix + '" class="time_ago">a day ago</span>'); } else if (difference < 2635200) { amount = floor(difference / 86400); $(".time_ago").text('<span unix="' + unix + '" class="time_ago">' + amount + ' days ago</span>'); } else if (difference < 5270400) { $(".time_ago").text('<span unix="' + unix + '" class="time_ago">a month ago</span>'); } else if (difference < 31622400) { amount = floor(difference / 2635200); $(".time_ago").text('<span unix="' + unix + '" class="time_ago">' + amount + ' months ago</span>'); } else if (difference < 63244800) { $(".time_ago").text('<span unix="' + unix + '" class="time_ago">a year ago</span>'); } else (difference >= 63244800) { amount = floor(difference / 31622400); $(".time_ago").text('<span unix="' + unix + '" class="time_ago">' + amount + ' years ago</span>'); } return false; }, 60); EDIT) Ok, now I have made some changes on your advice but it's changing the span texts to 43351 years. Any ideas why it is doing that?

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• merging UIImagePickerController image with cameraOverlayView

  - by GameDev

  Im really in the need for some help and advice. Spent the last week on this and have now just become frustrated as i cant get it to work! Basically, im trying to merge two images into one image to display/save. First the user picks an image from album, it goes to edit image screen where user can move and scale the image. On this screen is an overlay image (320x480) for the person to align there eyes in. Once aligned I want to save this image (edited and overlay) into one and pass the image onto my next screen. It works fine when the image is filling the edit/crop box, but when the image is widescreen with top and bottom not filling the box, then when i save the image the coords of the overlay dont get saved correctly! Heres my code, ive tried various ways of doing this but have failed at every attempt :( - (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { // Access the cropped image from info dictionary UIImage *image = [info objectForKey:@"UIImagePickerControllerEditedImage"]; // Combine image with overlay before saving!! image = [self addOverlayToImage:image]; overlayGraphicView.image = nil; // Take the picture image to the post picture view controller postPictureView = [[PostPictureViewController alloc] init:image Company:companyName withLink:buyButtonLink]; [picker pushViewController:postPictureView animated:YES]; [picker release],picker = nil; } The problem is that the image picked (originalImage) could be of any height, my overlayImage is however always 320x480, its almost all transparent with just two eye images in center which i want to save over the original images eyes! - (UIImage*) addOverlayToImage:(UIImage*)originalImage { CGRect cgRect =[[UIScreen mainScreen] bounds]; CGSize size = cgRect.size; UIGraphicsBeginImageContext(size); [originalImage drawInRect:CGRectMake(0, 0, size.width, size.height)]; UIImage* overlayImage = [UIImage imageNamed:overlayGraphicName]; [(UIImage *)overlayImage drawInRect:CGRectMake(0, 0, size.width, size.height)]; UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext(); [finalImage retain]; UIGraphicsEndImageContext(); return finalImage; } I wish there was just an easy way to take a screenshot of whatever is in the edit crop box :( Please if someone could help me with this ASAP as I need to finish this in 1-2 days time! Thank you. EDIT:- I should also mention that with this I get the correct center of the screen and placement of the overlay on my next screen: [(UIImage *)overlayImage drawInRect:CGRectMake(0, 0, size.width, size.height)]; However, I am unable to work out the correct position of the main image especially as the height is different for every image if not fullscreen! I tried this to center it into the correct position but it doesnt work: [originalImage drawInRect:CGRectMake(0,(size.height/2 - originalImage.size.height/2), originalImage.size.width, originalImage.size.height)];

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• What are the benefits of using ORM over XML Serialization/Deserialization?

  - by Tequila Jinx

  I've been reading about NHibernate and Microsoft's Entity Framework to perform Object Relational Mapping against my data access layer. I'm interested in the benefits of having an established framework to perform ORM, but I'm curious as to the performance costs of using it against standard XML Serialization and Deserialization. Right now, I develop stored procedures in Oracle and SQL Server that use XML Types for either input or output parameters and return or shred XML depending on need. I use a custom database command object that uses generics to deserialize the XML results into a specified serializable class. By using a combination of generics, xml (de)serialization and Microsoft's DAAB, I've got a process that's fairly simple to develop against regardless of the data source. Moreover, since I exclusively use Stored Procedures to perform database operations, I'm mostly protected from changes in the data structure. Here's an over-simplified example of what I've been doing. static void main() { testXmlClass test = new test(1); test.Name = "Foo"; test.Save(); } // Example Serializable Class ------------------------------------------------ [XmlRootAttribute("test")] class testXmlClass() { [XmlElement(Name="id")] public int ID {set; get;} [XmlElement(Name="name")] public string Name {set; get;} //create an instance of the class loaded with data. public testXmlClass(int id) { GenericDBProvider db = new GenericDBProvider(); this = db.ExecuteSerializable("myGetByIDProcedure"); } //save the class to the database... public Save() { GenericDBProvider db = new GenericDBProvider(); db.AddInParameter("myInputParameter", DbType.XML, this); db.ExecuteSerializableNonQuery("mySaveProcedure"); } } // Database Handler ---------------------------------------------------------- class GenericDBProvider { public T ExecuteSerializable<T>(string commandText) where T : class { XmlSerializer xml = new XmlSerializer(typeof(T)); // connection and command code is assumed for the purposes of this example. // the final results basically just come down to... return xml.Deserialize(commandResults) as T; } public void ExecuteSerializableNonQuery(string commandText) { // once again, connection and command code is assumed... // basically, just execute the command along with the specified // parameters which have been serialized. } public void AddInParameter(string name, DbType type, object value) { StringWriter w = new StringWriter(); XmlSerializer x = new XmlSerializer(value.GetType()); //handle serialization for serializable classes. if (type == DbType.Xml && (value.GetType() != typeof(System.String))) { x.Serialize(w, value); w.Close(); // store serialized object in a DbParameterCollection accessible // to my other methods. } else { //handle all other parameter types } } } I'm starting a new project which will rely heavily on database operations. I'm very curious to know whether my current practices will be sustainable in a high-traffic situation and whether or not I should consider switching to NHibernate or Microsoft's Entity Framework to perform what essentially seems to boil down to the same thing I'm currently doing. I appreciate any advice you may have.

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• How to make freelance clients understand the costs of developing and maintaining mature products?

  - by John

  I have a freelance web application project where the client requests new features every two weeks or so. I am unable to anticipate the requirements of upcoming features. So when the client requests a new feature, one of several things may happen: I implement the feature with ease because it is compatible with the existing platform I implement the feature with difficulty because I have to rewrite a significant portion of the platform's foundation Client withdraws request because it costs too much to implement against existing platform At the beginning of the project, for about six months, all feature requests fell under category 1) because the system was small and agile. But for the past six months, most feature implementation fell under category 2). The system is mature, forcing me to refactor and test everytime I want to add new modules. Additionally, I find myself breaking things that use to work, and fixing it (I don't get paid for this). The client is starting to express frustration at the time and cost for me to implement new features. To them, many of the feature requests are of the same scale as the features they requested six months ago. For example, a client would ask, "If it took you 1 week to build a ticketing system last year, why does it take you 1 month to build an event registration system today? An event registration system is much simpler than a ticketing system. It should only take you 1 week!" Because of this scenario, I fear feature requests will soon land in category 3). In fact, I'm already eating a lot of the cost myself because I volunteer many hours to support the project. The client is often shocked when I tell him honestly the time it takes to do something. The client always compares my estimates against the early months of a project. I don't think they're prepared for what it really costs to develop, maintain and support a mature web application. When working on a salary for a full time company, managers were more receptive of my estimates and even encouraged me to pad my numbers to prepare for the unexpected. Is there a way to condition my clients to think the same way? Can anyone offer advice on how I can continue to work on this web project without eating too much of the cost myself? Additional info - I've only been freelancing full time for 1 year. I don't yet have the high end clients, but I'm slowly getting there. I'm getting better quality clients as time goes by.

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• Performance Optimization for Matrix Rotation

  - by Summer_More_More_Tea

  Hello everyone: I'm now trapped by a performance optimization lab in the book "Computer System from a Programmer's Perspective" described as following: In a N*N matrix M, where N is multiple of 32, the rotate operation can be represented as: Transpose: interchange elements M(i,j) and M(j,i) Exchange rows: Row i is exchanged with row N-1-i A example for matrix rotation(N is 3 instead of 32 for simplicity): ------- ------- |1|2|3| |3|6|9| ------- ------- |4|5|6| after rotate is |2|5|8| ------- ------- |7|8|9| |1|4|7| ------- ------- A naive implementation is: #define RIDX(i,j,n) ((i)*(n)+(j)) void naive_rotate(int dim, pixel *src, pixel *dst) { int i, j; for (i = 0; i < dim; i++) for (j = 0; j < dim; j++) dst[RIDX(dim-1-j, i, dim)] = src[RIDX(i, j, dim)]; } I come up with an idea by inner-loop-unroll. The result is: Code Version Speed Up original 1x unrolled by 2 1.33x unrolled by 4 1.33x unrolled by 8 1.55x unrolled by 16 1.67x unrolled by 32 1.61x I also get a code snippet from pastebin.com that seems can solve this problem: void rotate(int dim, pixel *src, pixel *dst) { int stride = 32; int count = dim >> 5; src += dim - 1; int a1 = count; do { int a2 = dim; do { int a3 = stride; do { *dst++ = *src; src += dim; } while(--a3); src -= dim * stride + 1; dst += dim - stride; } while(--a2); src += dim * (stride + 1); dst -= dim * dim - stride; } while(--a1); } After carefully read the code, I think main idea of this solution is treat 32 rows as a data zone, and perform the rotating operation respectively. Speed up of this version is 1.85x, overwhelming all the loop-unroll version. Here are the questions: In the inner-loop-unroll version, why does increment slow down if the unrolling factor increase, especially change the unrolling factor from 8 to 16, which does not effect the same when switch from 4 to 8? Does the result have some relationship with depth of the CPU pipeline? If the answer is yes, could the degrade of increment reflect pipeline length? What is the probable reason for the optimization of data-zone version? It seems that there is no too much essential difference from the original naive version. EDIT: My test environment is Intel Centrino Duo processor and the verion of gcc is 4.4 Any advice will be highly appreciated! Kind regards!

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• Middleware with generic communication media layer

  - by Tom

  Greetings all, I'm trying to implement middleware (driver) for an embedded device with generic communication media layer. Not sure what is the best way to do it so I'm seeking an advice from more experienced stackoverflow users:). Basically we've got devices around the country communicating with our servers (or a pda/laptop in used in field). Usual form of communication is over TCP/IP, but could be also using usb, RF dongle, IR, etc. The plan is to have object corresponding with each of these devices, handling the proprietary protocol on one side and requests/responses from other internal systems on the other. The thing is how create something generic in between the media and the handling objects. I had a play around with the TCP dispatcher using boost.asio but trying to create something generic seems like a nightmare :). Anybody tried to do something like that? What is the best way how to do it? Example: Device connects to our Linux server. New middleware instance is created (on the server) which announces itself to one of the running services (details are not important). The service is responsible for making sure that device's time is synchronized. So it asks the middleware what is the device's time, driver translates it to device language (protocol) and sends the message, device responses and driver again translates it for the service. This might seem as a bit overkill for such a simple request but imagine there are more complex requests which the driver must translate, also there are several versions of the device which use different protocol, etc. but would use the same time sync service. The goal is to abstract the devices through the drivers to be able to use the same service to communicate with them. Another example: we find out that the remote communications with the device are down. So we send somebody out with PDA, he connects to the device using USB cable. Starts up the application which has the same functionality as the timesync service. Again middleware instance is created (on the PDA) to translate communication between application and the device this time only using USB/serial media not TCP/IP as in previous example. I hope it makes more sense now :) Cheers, Tom

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• How do I create a list or set object in a class in Python?

  - by Az

  For my project, the role of the Lecturer (defined as a class) is to offer projects to students. Project itself is also a class. I have some global dictionaries, keyed by the unique numeric id's for lecturers and projects that map to objects. Thus for the "lecturers" dictionary (currently): lecturer[id] = Lecturer(lec_name, lec_id, max_students) I'm currently reading in a white-space delimited text file that has been generated from a database. I have no direct access to the database so I haven't much say on how the file is formatted. Here's a fictionalised snippet that shows how the text file is structured. Please pardon the cheesiness. 0001 001 "Miyamoto, S." "Even Newer Super Mario Bros" 0002 001 "Miyamoto, S." "Legend of Zelda: Skies of Hyrule" 0003 002 "Molyneux, P." "Project Milo" 0004 002 "Molyneux, P." "Fable III" 0005 003 "Blow, J." "Ponytail" The structure of each line is basically proj_id, lec_id, lec_name, proj_name. Now, I'm currently reading the relevant data into the relevant objects. Thus, proj_id is stored in class Project whereas lec_name is a class Lecturer object, et al. The Lecturer and Project classes are not currently related. However, as I read in each line from the text file, for that line, I wish to read in the project offered by the lecturer into the Lecturer class; I'm already reading the proj_id into the Project class. I'd like to create an object in Lecturer called offered_proj which should be a set or list of the projects offered by that lecturer. Thus whenever, for a line, I read in a new project under the same lec_id, offered_proj will be updated with that project. If I wanted to get display a list of projects offered by a lecturer I'd ideally just want to use print lecturers[lec_id].offered_proj. My Python isn't great and I'd appreciate it if someone could show me a way to do that. I'm not sure if it's better as a set or a list, as well. Update After the advice from Alex Martelli and Oddthinking I went back and made some changes and tried to print the results. Here's the code snippet: for line in csv_file: proj_id = int(line[0]) lec_id = int(line[1]) lec_name = line[2] proj_name = line[3] projects[proj_id] = Project(proj_id, proj_name) lecturers[lec_id] = Lecturer(lec_id, lec_name) if lec_id in lecturers.keys(): lecturers[lec_id].offered_proj.add(proj_id) print lec_id, lecturers[lec_id].offered_proj The print lecturers[lec_id].offered_proj line prints the following output: 001 set([0001]) 001 set([0002]) 002 set([0003]) 002 set([0004]) 003 set([0005]) It basically feels like the set is being over-written or somesuch. So if I try to print for a specific lecturer print lec_id, lecturers[001].offered_proj all I get is the last the proj_id that has been read in.

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• ASP.NET MVC Custom Error Pages with Magical Unicorn

  - by FLClover

  my question is regarding Pure.Kromes answer to this post. I tried implementing my pages' custom error messages using his method, yet there are some problems I can't quite explain. a) When I provoke a 404 Error by entering in invalid URL such as localhost:3001/NonexistantPage, it defaults to the ServerError() Action of my error controller even though it should go to NotFound(). Here is my ErrorController: public class ErrorController : Controller { public ActionResult NotFound() { Response.TrySkipIisCustomErrors = true; Response.StatusCode = (int)HttpStatusCode.NotFound; var viewModel = new ErrorViewModel() { ServerException = Server.GetLastError(), HTTPStatusCode = Response.StatusCode }; return View(viewModel); } public ActionResult ServerError() { Response.TrySkipIisCustomErrors = true; Response.StatusCode = (int)HttpStatusCode.InternalServerError; var viewModel = new ErrorViewModel() { ServerException = Server.GetLastError(), HTTPStatusCode = Response.StatusCode }; return View(viewModel); } } My error routes in Global.asax.cs: routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.IgnoreRoute("{*favicon}", new { favicon = @"(.*/)?favicon.ico(/.*)?" }); routes.MapRoute( name: "Error - 404", url: "NotFound", defaults: new { controller = "Error", action = "NotFound" } ); routes.MapRoute( name: "Error - 500", url: "ServerError", defaults: new { controller = "Error", action = "ServerError" } ); And my web.config settings: <system.web> <customErrors mode="On" redirectMode="ResponseRewrite" defaultRedirect="/ServerError"> <error statusCode="404" redirect="/NotFound" /> </customErrors> ... </system.web> <system.webServer> <httpErrors errorMode="Custom" existingResponse="Replace"> <remove statusCode="404" subStatusCode="-1" /> <error statusCode="404" path="/NotFound" responseMode="ExecuteURL" /> <remove statusCode="500" subStatusCode="-1" /> <error statusCode="500" path="/ServerError" responseMode="ExecuteURL" /> </httpErrors> ... The Error views are located in /Views/Error/ as NotFound.cshtml and ServerError.cshtml. b) One funny thing is, When a server error occurs, it does in fact display the Server Error view I defined, however it also outputs a default error message as well saying that the Error page could not be found. Here's how it looks like: Do you have any advice how I could fix these two problems? I really like Pure.Kromes approach to implementing these error messages, but if there are better ways of achieving this don't hestitate to tell me. Thanks! *EDIT : * I can directly navigate to my views through the ErrorController by accessing /Error/NotFound or Error/ServerError. The views themselves only contain some text, no markup or anything. As I said, it actually works in some way, just not the way I intended it to work. There seems to be an issue with the redirect in the web.config, but I haven't been able to figure it out.

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• A Question about using jython when run a receving socket in python

  - by abusemind

  Hi, I have not a lot of knowledge of python and network programming. Currently I am trying to implement a simple application which can receive a text message sent by the user, fetch some information from the google search api, and return the results via text message to the user. This application will continue to listening to the users messages and reply immediately. How I get the text short message sent by the user? It's a program named fetion from the mobile supplier in China. The client side fetion, just like a instant communication tool, can send/receive messages to/from other people who are using mobile to receive/send SMS. I am using a open source python program that simulates the fetion program. So basically I can use this python program to communate with others who using cell phone via SMS. My core program is based on java, so I need to take this python program into java environment. I am using jython, and now I am available to send messages to users by some lines of java codes. But the real question is the process of receving from users via SMS. In python code, a new thread is created to continuously listen to the user. It should be OK in Python, but when I run the similar process in Jython, the following exception occurs: Exception in thread Thread:Traceback (most recent call last): File "D:\jython2.5.1\Lib\threading.py", line 178, in _Thread__bootstrap self.run() File "<iostream>", line 1389, in run File "<iostream>", line 1207, in receive File "<iostream>", line 1207, in receive File "<iostream>", line 150, in recv File "D:\jython2.5.1\Lib\select.py", line 223, in native_select pobj.register(fd, POLLIN) File "D:\jython2.5.1\Lib\select.py", line 104, in register raise _map_exception(jlx) error: (20000, 'socket must be in non-blocking mode') The line 150 in the python code is as follows: def recv(self,timeout=False): if self.login_type == "HTTP": time.sleep(10) return self.get_offline_msg() pass else: if timeout: infd,outfd,errfd = select([self.__sock,],[],[],timeout)//<---line 150 here else: infd,outfd,errfd = select([self.__sock,],[],[]) if len(infd) != 0: ret = self.__tcp_recv() num = len(ret) d_print(('num',),locals()) if num == 0: return ret if num == 1: return ret[0] for r in ret: self.queue.put(r) d_print(('r',),locals()) if not self.queue.empty(): return self.queue.get() else: return "TimeOut" Because of I am not very familiar with python, especially the socket part, and also new in Jython use, I really need your help or only advice or explanation. Thank you very much!

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• Reverse proxy for a REST web service using ADFS/AD and WebApi

  - by Kai Friis

  I need to implement a reverse proxy for a REST webservice behind a firewall. The reverse proxy should authenticate against an enterprise ADFS 2.0 server, preferably using claims in .net 4.5. The clients will be a mix of iOS, Android and web. I’m completely new to this topic; I’ve tried to implement the service as a REST service using WebApi, WIF and the new Identity and Access control in VS 2012, with no luck. I have also tried to look into Brock Allen’s Thinktecture.IdentityModel.45, however then my head was spinning so I didn’t see the difference between it and Windows Identity Foundation with the Identity and Access control. So I think I need to step back and get some advice on how to do this. There are several ways to this, as far as I understand it. In hardware. Set up our Citrix Netscaler as a reverse proxy. I have no idea how to do that, however if it’s a good solution I can always hire someone who knows… Do it in the webserver, like IIS. I haven’t tried it; do not know if it will work. Create a web service to do it. 3.1 Implement it as a SOAP service using WCF. As I understand it ADFS do not support REST so I have to use SOAP. The problem is mobile device do not like SOAP, neither do I… However if it’s the best way, I have to do it. 3.2 Use Azure Access Control Service. It might work, however the timing is not good. Our enterprise is considering several cloud options, and us jumping on the azure wagon on our own might not be the smartest thing to do right now. However if it is the only options, we can do it. I just prefer not to use it right now. Right now I feel there are too many options, and I do not know which one will work. If someone can point me in the right directions, which path to pursue, I would be very grateful.

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• Inference engine to calculate matching set according to internal rules

  - by Zecrates

  I have a set of objects with attributes and a bunch of rules that, when applied to the set of objects, provides a subset of those objects. To make this easier to understand I'll provide a concrete example. My objects are persons and each has three attributes: country of origin, gender and age group (all attributes are discrete). I have a bunch of rules, like "all males from the US", which correspond with subsets of this larger set of objects. I'm looking for either an existing Java "inference engine" or something similar, which will be able to map from the rules to a subset of persons, or advice on how to go about creating my own. I have read up on rule engines, but that term seems to be exclusively used for expert systems that externalize the business rules, and usually doesn't include any advanced form of inferencing. Here are some examples of the more complex scenarios I have to deal with: I need the conjunction of rules. So when presented with both "include all males" and "exclude all US persons in the 10 - 20 age group," I'm only interested in the males outside of the US, and the males within the US that are outside the 10 - 20 age group. Rules may have different priorities (explicitly defined). So a rule saying "exclude all males" will override a rule saying "include all US males." Rules may be conflicting. So I could have both an "include all males" and an "exclude all males" in which case the priorities will have to settle the issue. Rules are symmetric. So "include all males" is equivalent to "exclude all females." Rules (or rather subsets) may have meta rules (explicitly defined) associated with them. These meta rules will have to be applied in any case that the original rule is applied, or if the subset is reached via inferencing. So if a meta rule of "exclude the US" is attached to the rule "include all males", and I provide the engine with the rule "exclude all females," it should be able to inference that the "exclude all females" subset is equivalent to the "include all males" subset and as such apply the "exclude the US" rule additionally. I can in all likelihood live without item 5, but I do need all the other properties mentioned. Both my rules and objects are stored in a database and may be updated at any stage, so I'd need to instantiate the 'inference engine' when needed and destroy it afterward.

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• Problem in loading cities using JSON

  - by Saravanan I M

  I am using Geonames for loading the cities using JSON. Geonames data i imported into my database. I am using MS SQL 2008 Server. I display a dropdown for country select. Once the user select the country. I am loading all the cities into the autocomplete textbox. I am facing a delay in the getJSON method. Also it seems like executing asynchronous. So before getting all the data my autocompelte is getting filled. Below is my complete script. I think i have some problem in the loop. Please advice me what i am doing wrong in my code. $(document).ready(function () { $("#ShowLoad").hide(); //Hook onto the MakeID list's onchange event $("#Country").change(function () { findcities = []; $("#ShowLoad").show(); $("#HomeTown").unautocomplete(); var url = '<%= Url.Content("~/") %>' + "Location/GetCitiesCountByCountry/" + $("#Country").val(); $.getJSON(url, null, function (data) { var total = data; if (total > 0) { var pageTotal = Math.ceil(total / 1000); var isFilled = false; for (var i = 0; i < pageTotal; i++) { var skip = i == 1 ? 0 : (i * 1000) - 1000; var url = '<%= Url.Content("~/") %>' + "Location/GetCitiesByCountry/" + $("#Country").val() + "?skip=" + skip; //alert(i); $.getJSON(url, null, function (data) { $.each(data.Cities, function (index, optionData) { if ($("#Country").val() == "US") { findcities.push(optionData.asciiname + "," + optionData.admin1_code); } else { findcities.push(optionData.asciiname); } }); if (i == pageTotal) { //alert(findcities); $("#ShowLoad").hide(); $("#HomeTown").focus().autocomplete(findcities); } }); } $("#HomeTown").setOptions({ max: 100000 }); } }); }).change(); });

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• Java "compare cannot be resolved to a type" error

  - by King Triumph

  I'm getting a strange error when attempting to use a comparator with a binary search on an array. The error states that "compareArtist cannot be resolved to a type" and is thrown by Eclipse on this code: Comparator<Song> compare = new Song.compareArtist(); I've done some searching and found references to a possible bug with Eclipse, although I have tried the code on a different computer and the error persists. I've also found similar issues regarding the capitalization of the compare method, in this case compareArtist. I've seen examples where the first word in the method name is capitalized, although it was my understanding that method names are traditionally started with a lower case letter. I have experimented with changing the capitalization but nothing has changed. I have also found references to this error if the class doesn't import the correct package. I have imported java.util in both classes in question, which to my knowledge allows the use of the Comparator. I've experimented with writing the compareArtist method within the class that has the binary search call as well as in the "Song" class, which according to my homework assignment is where it should be. I've changed the constructor accordingly and the issue persists. Lastly, I've attempted to override the Comparator compare method by implementing Comparator in the Song class and creating my own method called "compare". This returns the same error. I've only moved to calling the comparator method something different than "compare" after finding several examples that do the same. Here is the relevant code for the class that calls the binary search that uses the comparator. This code also has a local version of the compareArtist method. While it is not being called currently, the code for this method is the same as the in the class Song, where I am trying to call it from. Thanks for any advice and insight. import java.io.*; import java.util.*; public class SearchByArtistPrefix { private Song[] songs; // keep a direct reference to the song array private Song[] searchResults; // holds the results of the search private ArrayList<Song> searchList = new ArrayList<Song>(); // hold results of search while being populated. Converted to searchResults array. public SearchByArtistPrefix(SongCollection sc) { songs = sc.getAllSongs(); } public int compareArtist (Song firstSong, Song secondSong) { return firstSong.getArtist().compareTo(secondSong.getArtist()); } public Song[] search(String artistPrefix) { String artistInput = artistPrefix; int searchLength = artistInput.length(); Song searchSong = new Song(artistInput, "", ""); Comparator<Song> compare = new Song.compareArtist(); int search = Arrays.binarySearch(songs, searchSong, compare);

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• How to order a HasMany collection by a child property with Fluent NHibernate mapping

  - by Geoff Hardy

  I am using Fluent NHibernate to map the following classes: public abstract class DomainObject { public virtual int Id { get; protected internal set; } } public class Attribute { public virtual string Name { get; set; } } public class AttributeRule { public virtual Attribute Attribute { get; set; } public virtual Station Station { get; set; } public virtual RuleTypeId RuleTypeId { get; set; } } public class Station : DomainObject { public virtual IList<AttributeRule> AttributeRules { get; set; } public Station() { AttributeRules = new List<AttributeRule>(); } } My Fluent NHibernate mappings look like this: public class AttributeMap : ClassMap<Attribute> { public AttributeMap() { Id(o => o.Id); Map(o => o.Name); } } public class AttributeRuleMap : ClassMap<AttributeRule> { public AttributeRuleMap() { Id(o => o.Id); Map(o => o.RuleTypeId); References(o => o.Attribute).Fetch.Join(); References(o => o.Station); } } public class StationMap : ClassMap<Station> { public StationMap() { Id(o => o.Id); HasMany(o => o.AttributeRules).Inverse(); } } I would like to order the AttributeRules list on Station by the Attribute.Name property, but doing the following does not work: HasMany(o => o.AttributeRules).Inverse().OrderBy("Attribute.Name"); I have not found a way to do this yet in the mappings. I could create a IQuery or ICriteria to do this for me, but ideally I would just like to have the AttributeRules list sorted when I ask for it. Any advice on how to do this mapping?

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• PostgreSQL - fetch the row which has the Max value for a column

  - by Joshua Berry

  I'm dealing with a Postgres table (called "lives") that contains records with columns for time_stamp, usr_id, transaction_id, and lives_remaining. I need a query that will give me the most recent lives_remaining total for each usr_id There are multiple users (distinct usr_id's) time_stamp is not a unique identifier: sometimes user events (one by row in the table) will occur with the same time_stamp. trans_id is unique only for very small time ranges: over time it repeats remaining_lives (for a given user) can both increase and decrease over time example: time_stamp|lives_remaining|usr_id|trans_id ----------------------------------------- 07:00 | 1 | 1 | 1 09:00 | 4 | 2 | 2 10:00 | 2 | 3 | 3 10:00 | 1 | 2 | 4 11:00 | 4 | 1 | 5 11:00 | 3 | 1 | 6 13:00 | 3 | 3 | 1 As I will need to access other columns of the row with the latest data for each given usr_id, I need a query that gives a result like this: time_stamp|lives_remaining|usr_id|trans_id ----------------------------------------- 11:00 | 3 | 1 | 6 10:00 | 1 | 2 | 4 13:00 | 3 | 3 | 1 As mentioned, each usr_id can gain or lose lives, and sometimes these timestamped events occur so close together that they have the same timestamp! Therefore this query won't work: SELECT b.time_stamp,b.lives_remaining,b.usr_id,b.trans_id FROM (SELECT usr_id, max(time_stamp) AS max_timestamp FROM lives GROUP BY usr_id ORDER BY usr_id) a JOIN lives b ON a.max_timestamp = b.time_stamp Instead, I need to use both time_stamp (first) and trans_id (second) to identify the correct row. I also then need to pass that information from the subquery to the main query that will provide the data for the other columns of the appropriate rows. This is the hacked up query that I've gotten to work: SELECT b.time_stamp,b.lives_remaining,b.usr_id,b.trans_id FROM (SELECT usr_id, max(time_stamp || '*' || trans_id) AS max_timestamp_transid FROM lives GROUP BY usr_id ORDER BY usr_id) a JOIN lives b ON a.max_timestamp_transid = b.time_stamp || '*' || b.trans_id ORDER BY b.usr_id Okay, so this works, but I don't like it. It requires a query within a query, a self join, and it seems to me that it could be much simpler by grabbing the row that MAX found to have the largest timestamp and trans_id. The table "lives" has tens of millions of rows to parse, so I'd like this query to be as fast and efficient as possible. I'm new to RDBM and Postgres in particular, so I know that I need to make effective use of the proper indexes. I'm a bit lost on how to optimize. I found a similar discussion here. Can I perform some type of Postgres equivalent to an Oracle analytic function? Any advice on accessing related column information used by an aggregate function (like MAX), creating indexes, and creating better queries would be much appreciated! P.S. You can use the following to create my example case: create TABLE lives (time_stamp timestamp, lives_remaining integer, usr_id integer, trans_id integer); insert into lives values ('2000-01-01 07:00', 1, 1, 1); insert into lives values ('2000-01-01 09:00', 4, 2, 2); insert into lives values ('2000-01-01 10:00', 2, 3, 3); insert into lives values ('2000-01-01 10:00', 1, 2, 4); insert into lives values ('2000-01-01 11:00', 4, 1, 5); insert into lives values ('2000-01-01 11:00', 3, 1, 6); insert into lives values ('2000-01-01 13:00', 3, 3, 1);

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• MVC Rendered Partial, how to get partial/view model in main model post to controller

  - by user1475788

  I have a text file and when users upload the file, the controller action method parses that file using state machine and uses a generic list to store some values. I pass this back to the view in the form of an IEnumerable. Within my main view, based on this ienumerable list I render a partail view to iterate items and display labels and a textarea. Users could add their input in the text area. When the users hit the save button this ienumrable list from the partial view rendered is null. so please advice any solutions. here is my main view @model RunLog.Domain.Entities.RunLogEntry @{ ViewBag.Title = "Create"; Layout = "~/Views/Shared/_Layout.cshtml"; } @using (Html.BeginForm("Create", "RunLogEntry", FormMethod.Post, new { enctype = "multipart/form-data" })) { <div id="inputTestExceptions" style="display: none;"> <table class="grid" style="width: 450px; margin: 3px 3px 3px 3px;"> <thead> <tr> <th> Exception String </th> <th> Comment </th> </tr> </thead> <tbody> @if (Model.TestExceptions != null) { foreach (var p in Model.TestExceptions) { Html.RenderPartial("RunLogTestExceptionSummary", p); } } </tbody> </table> </div> } partial view as follows: @model RunLog.Domain.Entities.RunLogEntryTestExceptionDisplay <tr> <td> @Model.TestException@ </td> <td>@Html.TextAreaFor(Model.Comment, new { style = "width: 200px; height: 80px;" }) </td> </tr> Controller action [HttpPost] public ActionResult Create(RunLogEntry runLogEntry, String ServiceRequest, string Hour, string Minute, string AMPM, string submit, IEnumerable<HttpPostedFileBase> file, String AssayPerformanceIssues1, IEnumerable<RunLogEntryTestExceptionDisplay> models) { } The problem is test exceptions which contains exception string and comment is comming back null.

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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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• Looking for Fiddler2 help. connection to gateway refused? Just got rid of a virus

  - by John Mackey

  I use Fiddler2 for facebook game items, and it's been a great success. I accessed a website to download some dat files I needed. I think it was eshare, ziddu or megaupload, one of those. Anyway, even before the rar file had downloaded, I got this weird green shield in the bottom right hand corner of my computer. It said a Trojan was trying to access my computer, or something to that extent. It prompted me to click the shield to begin anti-virus scanning. It turns out this rogue program is called Antivirus System Pro and is pretty hard to get rid of. After discovering the rogue program, I tried using Fiddler and got the following error: [Fiddler] Connection to Gateway failed.Exception Text: No connection could be made because the target machine actively refused it 127.0.0.1:5555 I ended up purchasing SpyDoctor + Antivirus, which I'm told is designed specifically for getting rid of these types of programs. Anyway, I did a quick-scan last night with spydoctor and malware bytes. Malware picked up 2 files, and Spydoctor found 4. Most were insignificant, but it did find a worm called Worm.Alcra.F, which was labeled high-priority. I don’t know if that’s the Anti-Virus Pro or not, but SpyDoctor said it got rid of all of those successfully. I tried to run Fiddler again before leaving home, but was still getting the "gateway failed" error. Im using the newest version of firefox. When I initially set up the Fiddler 2.2.8.6, I couldn’t get it to run at first, so I found this faq on the internet that said I needed to go through ToolsOptionsSettings and set up an HTTP Proxy to 127.0.0.1 and my Port to 8888. Once I set that up and downloaded this fiddler helper as a firefox add-on, it worked fine. When I turn on fiddler, it automatically takes my proxy setting from no proxy (default) to the 127.0.0.1 with Port 8888 set up. It worked fine until my computer detected this virus. Anyway, hopefully I've given you sufficient information to offer me your best advice here. Like I said, Spydoctor says the bad stuff is gone, so maybe the rogue program made some type of change in my fiddler that I could just reset or uncheck or something like that? Or will I need to completely remove fiddler and those dat files and rar files I downloaded? Any help would be greatly appreciated. Thanks for your time.

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