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• Unit Testing in the real world

  - by Malfist

  I manage a rather large application (50k+ lines of code) by myself, and it manages some rather critical business actions. To describe the program simple, I would say it's a fancy UI with the ability to display and change data from the database, and it's managing around 1,000 rental units, and about 3k tenants and all the finances. When I make changes, because it's so large of a code base, I sometimes break something somewhere else. I typically test it by going though the stuff I changed at the functional level (i.e. I run the program and work through the UI), but I can't test for every situation. That is why I want to get started with unit testing. However, this isn't a true, three tier program with a database tier, a business tier, and a UI tier. A lot of the business logic is performed in the UI classes, and many things are done on events. To complicate things, everything is database driven, and I've not seen (so far) good suggestions on how to unit test database interactions. How would be a good way to get started with unit testing for this application. Keep in mind. I've never done unit testing or TDD before. Should I rewrite it to remove the business logic from the UI classes (a lot of work)? Or is there a better way?

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• calling Overloaded method from a generic method.

  - by asela38

  How to create a generic method which can call overloaded methods? I tried but it gives a compilation error. Test.java:19: incompatible types found : java.lang.Object required: T T newt = getCloneOf(t); ^ import java.util.*; public class Test { private Object getCloneOf(Object s) { return new Object(); } private String getCloneOf(String s) { return new String(s); } private <T> Set<T> getCloneOf(Set<T> set){ Set<T> newSet = null; if( null != set) { newSet = new HashSet<T>(); for (T t : set) { T newt = getCloneOf(t); newSet.add(newt); } } } }

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• Fatal error when using FILE* in Windows from DLL

  - by AlannY

  Hi there. Recently, I found a problem with Visual C++ 2008 compiler, but using minor hack avoid it. Currently, I cannot use the same hack, but problem exists as in 2008 as in 2010 (Express). So, I've prepared for you 2 simple C file: one for DLL, one for program: DLL (file-dll.c): #include <stdio.h> __declspec(dllexport) void print_to_stream (FILE *stream) { fprintf (stream, "OK!\n"); } And for program, which links this DLL via file-dll.lib: Program: #include <stdio.h> __declspec(dllimport) void print_to_stream (FILE *stream); int main (void) { print_to_stream (stdout); return 0; } To compile and link DLL: cl /LD file-dll.c To compile and link program: cl file-test.c file-dll.lib When invoking file-test.exe, I got the fatal error (similar to segmentation fault in UNIX). As I said early, I had that the same problem before: about transferring FILE* pointer to DLL. I thought, that it may be because of compiler mismatch, but now I'm using one compiler for everything and it's not the problem. ;-( What can I do now? UPD: I've found solution: cl /LD /MD file-dll.c cl /MD file-test.c file-dll.lib The key is to link to dynamic library, but (I did not know it) by default it links staticaly and (hencefore) error occurs (I see why). P.S. Thanks for patience.

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• Swing - how to mix JTextField and JTextAreas and have same visual appearance?

  - by I82Much

  I am using miglayout to create a form in which there are JTextFields (short input answers) as well as JTextAreas (Longer answers). The problem is twofold. The border placed around a Scrollpane wrapped text area does not match that of a Text Field. The width and placement of the textarea/textfield differ, causing them not to line up correctly. Source code: package test2; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTextArea; import javax.swing.JTextField; import net.miginfocom.swing.MigLayout; public class Test extends JPanel { private static final int NUM_CHARACTERS_WIDTH = 20; private static final int NUM_ROWS = 5; public Test() { setLayout(new MigLayout( "wrap 2", // Align text labels on the so their right edge meets left edge of the text fields "[right][left]" )); add(new JLabel("Text field:")); add(new JTextField(NUM_CHARACTERS_WIDTH)); add(new JLabel("No scrollpane text area:")); add(new JTextArea(NUM_ROWS, NUM_CHARACTERS_WIDTH)); add(new JLabel("Scrollpane text area:")); add(new JScrollPane(new JTextArea(NUM_ROWS, NUM_CHARACTERS_WIDTH))); add(new JLabel("Text field:")); add(new JTextField(NUM_CHARACTERS_WIDTH)); } public static void main(String[] args) { JFrame frame = new JFrame(""); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JPanel panel = new Test(); frame.add(panel); frame.pack(); frame.setVisible(true); } } What's the preferred way to mix and match jtextfield and jtextareas, while still maintaining visual harmony? I notice now that the text field has a blue highlight around it when focus is in it, as opposed to the text area... another source of visual discontinuity.

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• Coding guidelines + Best Practices?

  - by Chathuranga Chandrasekara

  I couldn't find any question that directly applies to my query so I am posting this as a new question. If there is any existing discussion that may help me, please point it out and close the question. Question: I am going to do a presentation on C# coding guidelines but it is not supposed to limit to coding standards. So I have a rough idea but I think I need to address good programing practices. So the contents will be something like this. Basic coding standards - Casing, Formatting etc. Good practices - Usage of Hashset over other data structures, String vs String Builder, String's immutability and using them effectively etc Really I would like to add more good practices (Especially to improve the performance.) So like to hear some more good practices to be used with C#. Any suggestions??? (No need of large descriptions :) Just the idea is sufficient.)

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• Why Automatically implemented properties must define both get and set accessors.

  - by Nasser Hajloo

  When we define a property like public string Name {get; set;} dot net can make our properties code. but when we use public string Name {get;} public string Name {set;} we face with 'Hajloo.SomeThing.PropertyName.set' must declare a body because it is not marked abstract or extern. Automatically implemented properties must define both get and set accessors. Actualy whay compiler can't determine the property and make code automatically ? what's happen ?

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• how to upload the fie from user to server in asp.net mvc2

  - by Richa Media and services

  in my apps (dev in MVC2) user can upload his images to server. how i can set url routing who handle the image and upload it to a specific location currently i used it like a parameter ex;- routes.MapRoute("abcd2", "abcd/{id}/{param1}/{param2}/", new { controller = "abcd", action = "Index", id = 0, qxt = "" }, new { action = new IsIndexConstraint() }, new string[] { "myapps.Controllers" }); by this code param2 is work i used param1 for sending file to server but he not worked public ActionResult Index(HttpPostedFileBase param1 , string param2) { string str = "null"; if (param1 != null) { param1.SaveAs(@"C:\img\" + param1.FileName); str = "func is work"; //picture.SaveAs("C:\wherever\" + picture.FileName); return Content(str); } else { str = "func is not worked"; } return Content(str); } are anyone really want to help me. param2 is work but param1 is not handle by web apps. are you suggest me how to do it.

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• read file in C++

  - by Amm Sokun

  I am trying to read a list of words from a file in C++. However, the last word is read twice. I cannot understand why it is so. Can someone help me out? int main () { ifstream fin, finn; vector<string> vin; vector<string> typo; string word; fin.open("F:\\coursework\\pz\\gattaca\\breathanalyzer\\file.in"); if (!fin.is_open()) cout<<"Not open\n"; while (fin) { fin >> word; cout<<word<<endl; vin.push_back(word); } fin.close(); }

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• When do I need to use automatic poperties and when properties with propertychanged event ?

  - by Honey

  Hello, I am using wpf and its C sharp! I have this in my Animal.cs clas private string _animalName; public string AnimalName { get { return _animalName; } set { if(_animalName!= value) { _animalName= value; this.NotifyPropertyChanged("AnimalName"); } } } I could also write: public string AnimalName {get;set;} There is no difference in binding and validation. Everythings works as before when I exchange the code. Is this due to the fact that I only create new animals but I do not allow to update the animals name in my application ? So I need to call the propertyChanged("AnimalName"); only when I want to change its property value? I am a c# beginner ;)

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• .Net website create directory to remote server access denied

  - by tmfkmoney

  I have a web application that creates directories. The application works fine when creating a directory on the web server, however, it does not work when it tries to create a directory on our remote fileserver. The fileserver and the webserver are in the same domain. I have created a local user in our domain, "DOMAIN\aspnet". The local user is on both servers. I am running my .Net app pool under the domain user. I have also tried using windows impersonate in the web.config to run under the domain user. I have verified that the domain user has full control to the remote directory. In an effort to debug this I have also given the "everyone" full control to the remote directory. In an effort to debug this I have also added the domain user to the administrators group. I have a simple .net test page on the web server to test this. Through the test page I am able to read the directory on the file server and get a list of everything in it. I am not able to upload files or to create directories on the file server. Here's code that works: var path = @"\\fileserver\images\"; var di = new DirectoryInfo(path); foreach (var d in di.GetDirectories()) { Response.Write(d.Name); } Here's code that doesn't work: path = Path.Combine(path, "NewDirectory"); Directory.CreateDirectory(path); Here's the error I'm getting: Access to the path '\fileserver\images\NewDirectory' is denied. I'm pretty stuck on this. Any ideas?

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• Centralized error handling in VB6.

  - by AngryHacker

  I have the following method that all the error handlers call: Public Function ToError(strClass As String, strMethod As String) As String On Error GoTo errHandle ToError = "Err " & Err.Number & _ ", Src: " & Err.Source & _ ", Dsc: " & Err.Description & _ ", Project: " & App.Title & _ ", Class: " & strClass & _ ", Method: " & strMethod & _ ", Line: " & Erl Err.Clear exitPoint: Exit Function errHandle: oLog.AddToLog "Error in ToError Method: " & Err.Description, False Resume exitPoint End Function It turns out that because I declare an error handler in this function On Error GoTo errHandle, VB6 clears the error before I am able to record it. Is there a way to prevent the 'On Error GoTo errHandle' statement from clearing the error?

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• Android Unable to launch the Inbox from a notification

  - by trpsbill

  I have the following code that creates a notification when an SMS message is received by the phone. It displays the notification correctly; however, when the user clicks the notification, nothing happens. It should open up the SMS inbox so the user can view their message. Thanks in advance. mNotificationManager = (NotificationManager) arg0.getSystemService(Context.NOTIFICATION_SERVICE); Uri uri = Uri.parse("content://sms/inbox"); PendingIntent contentIntent = PendingIntent.getActivity(arg0, 0, new Intent(Intent.ACTION_VIEW, uri), Intent.FLAG_ACTIVITY_NEW_TASK); String tickerText = arg0.getString(R.string.newmsg, msgs[i].getMessageBody().toString()); Notification notif = new Notification(R.drawable.icon, tickerText, System.currentTimeMillis()); notif.setLatestEventInfo(arg0, msgs[i].getOriginatingAddress(), msgs[i].getMessageBody().toString(), contentIntent); notif.vibrate = new long[] { 100, 250, 100, 500 }; mNotificationManager.notify(R.string.recv_msg_notif_id, notif);

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• Why is my NSMutableArray returning nill?

  - by lampShade

  I have a very simple task: add the contents of a textField to an NSMutableArray.The Problem is the array is returning nill. I believe that it has something to do with the fact that the array I'm using is declared as an instance variable. /* IBOutlet NSTextField *textField; IBOutlet NSTabView *tableView; IBOutlet NSButton *button; NSMutableArray *myArray; */ #import "AppController.h" @implementation AppController -(IBAction)addNewItem:(id)sender { NSString *string = [textField stringValue]; NSLog(@"%@",string); [myArray addObject:string]; NSLog(@"%d",[myArray count]);//this outputs 0 why is that? }

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• Passing custom Python objects to nosetests

  - by Rob

  I am attempting to re-organize our test libraries for automation and nose seems really promising. My question is, what is the best strategy for passing Python objects into nose tests? Our tests are organized in a testlib with a bunch of modules that exercise different types of request operations. Something like this: testlib \-testmoda \-testmodb \-testmodc In some cases the test modules (i.e. testmoda) is nothing but test_something(), test_something2() functions while in some cases we have a TestModB class in testmob with the test_anotherthing1(), test_anotherthing2() functions. The cool thing is that nose easily finds both. Most of those test functions are request factory stuff that can easily share a single connection to our server farm. Thus we do a lot of test_something1(cnn), TestModB.test_anotherthing2(cnn), etc. Currently we don't use nose, instead we have a hodge-podge of homegrown driver scripts with hard-coded lists of tests to execute. Each of those driver scripts creates its own connection object. Maintaining those scripts and the connection minutia is painful. I'd like to take free advantage of nose's beautiful discovery functionality, passing in a connection object of my choosing. Thanks in advance! Rob P.S. The connection objects are not pickle-able. :(

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• Custom View embed in Gallery crashes while key press

  - by tao

  Hi there, I'd like to find some stuff to replace the Tab component, so I'd make a custom View named StringView, which has the ability to display text, and to embed it into a Gallery. But it always crashes with error "NullPointerException at InputMethodManager". I have no idea about this, any help&tip&suggest are appreciate. Detail of my issue: First I'd created a class StringView extends View: public class StringView extends View { protected final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); protected String mString; protected int mAscent; // Constructor public StringView(Context context, String string) { super(context); mPaint.setARGB(255, 255, 60, 10); mPaint.setTextSize(30); //mPaint.setFakeBoldText(true); mString = string; setPadding(20,15,20,15); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); int w = this.getPaddingLeft(); int h = this.getPaddingTop() - mAscent; canvas.drawText(mString, w, h, mPaint); } public void setString(String str) { mString = str; this.requestLayout(); this.invalidate(); } public String getString() { return mString; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { setMeasuredDimension(measureWidth(widthMeasureSpec), measureHeight(heightMeasureSpec)); } /** * Determines the width of this view * @param measureSpec A measureSpec packed into an int * @return The width of the view, honoring constraints from measureSpec */ private int measureWidth(int measureSpec) { int result = 0; int specMode = MeasureSpec.getMode(measureSpec); int specSize = MeasureSpec.getSize(measureSpec); if (specMode == MeasureSpec.EXACTLY) { // We were told how big to be result = specSize; } else { // Measure the text result = (int) mPaint.measureText(mString) + getPaddingLeft() + getPaddingRight(); if (specMode == MeasureSpec.AT_MOST) { // Respect AT_MOST value if that was what is called for by measureSpec result = Math.min(result, specSize); } } return result; } /** * Determines the height of this view * @param measureSpec A measureSpec packed into an int * @return The height of the view, honoring constraints from measureSpec */ private int measureHeight(int measureSpec) { int result = 0; int specMode = MeasureSpec.getMode(measureSpec); int specSize = MeasureSpec.getSize(measureSpec); mAscent = (int) mPaint.ascent(); if (specMode == MeasureSpec.EXACTLY) { // We were told how big to be result = specSize; } else { // Measure the text (beware: ascent is a negative number) result = (int) (-mAscent + mPaint.descent()) + getPaddingTop() + getPaddingBottom(); if (specMode == MeasureSpec.AT_MOST) { // Respect AT_MOST value if that was what is called for by measureSpec result = Math.min(result, specSize); } } return result; } } Second I put it in to Gallery through Adapter Gallery gallery = (Gallery) findViewById(R.id.gallery); gallery.setAdapter(new ImageAdapter(this)); ImageAdapter: public class ImageAdapter extends BaseAdapter { int mGalleryItemBackground; private Context mContext; private View[] mImages = genSerielImageViews(); public ImageAdapter(Context c) { mContext = c; TypedArray a = obtainStyledAttributes(R.styleable.Gallery); mGalleryItemBackground = a.getResourceId( R.styleable.Gallery_android_galleryItemBackground, 0); a.recycle(); } private View[] genSerielImageViews() { if (true) { int N = 6; StringView[] views = new StringView[N]; for (int i=0; i<N; i++) { views[i] = new StringView(mContext, "ITEM #" + Integer.toString(i) ); } return views; } else { int N = 6; TextView[] views = new TextView[N]; for (int i=0; i<N; i++) { views[i] = new TextView( mContext ); views[i].setText("CCTV #" + Integer.toString(i) ); } return views; } } public int getCount() { return mImages.length; } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { return mImages[position]; } } Then Compile&Run, press keypad RIGHT and I got a crash, It's turns out a weird InputMethodManager error: 03-18 07:22:33.568: ERROR/AndroidRuntime(958): Uncaught handler: thread main exiting due to uncaught exception 03-18 07:22:33.648: ERROR/AndroidRuntime(958): java.lang.NullPointerException 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.view.inputmethod.InputMethodManager.startInputInner(InputMethodManager.java:940) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.view.inputmethod.InputMethodManager.checkFocus(InputMethodManager.java:1114) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.view.ViewRoot.handleMessage(ViewRoot.java:1869) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.os.Handler.dispatchMessage(Handler.java:99) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.os.Looper.loop(Looper.java:123) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.app.ActivityThread.main(ActivityThread.java:4310) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at java.lang.reflect.Method.invokeNative(Native Method) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at java.lang.reflect.Method.invoke(Method.java:521) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at dalvik.system.NativeStart.main(Native Method) Thanks.

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• getline won't let me type, c++

  - by Stijn

  I try to get the name of a game the users chooses and store it in a vector. I use getline so the user can use a space. When I try to type a new game to add it won't let me. It automaticly displays me games library. Please tell me what I do wrong. Problem is at if(action == "add") Here's my code: #include <iostream> #include <string> #include <vector> #include <algorithm> #include <ctime> #include <cstdlib> using namespace std; int main() { vector<string>::const_iterator myIterator; vector<string>::const_iterator iter; vector<string> games; games.push_back("Crysis 2"); games.push_back("GodOfWar 3"); games.push_back("FIFA 12"); cout <<"Welcome to your Games Library.\n"; cout <<"\nThese are your games:\n"; for (iter = games.begin(); iter != games.end(); ++iter) { cout <<*iter <<endl; } //the loop! string action; string newGame; cout <<"\n-Type 'exit' if you want to quit.\n-Type 'add' if you want to add a game.\n-Type 'delete' if you want to delete a game.\n-Type 'find' if you want to search a game.\n-Type 'game' if you don't know what game to play.\n-Type 'show' if you want to view your library."; while (action != "exit") { cout <<"\n\nWhat do you want to do: "; cin >> action; //problem is here if (action == "add") { cout <<"\nType the name of the game you want to add: "; getline (cin, newGame); games.push_back(newGame); for (iter = games.begin(); iter != games.end(); ++iter) { cout <<*iter <<endl; } continue; } else if (action == "show") { cout <<"\nThese are your games:\n"; for (iter = games.begin(); iter != games.end(); ++iter) { cout <<*iter <<endl; } } else if (action == "delete") { cout <<"Type the name of the game you want to delete: "; cin >> newGame; getline (cin, newGame); iter = find(games.begin(), games.end(), newGame); if(iter != games.end()) { games.erase(iter); cout <<"\nGame deleted!"; } else { cout<<"\nGame not found."; } continue; } else if (action == "find") { cout <<"Which game you want to look for in your library: "; cin >> newGame; getline (cin, newGame); iter = find(games.begin(), games.end(), newGame); if (iter != games.end()) { cout << "Game found.\n"; } else { cout << "Game not found.\n"; } continue; } else if (action == "game") { srand(static_cast<unsigned int>(time(0))); random_shuffle(games.begin(), games.end()); cout << "\nWhy don't you play " << games[0]; continue; } else if (action == "quit") { cout <<"\nRemember to have fun while gaming!!\n"; break; } else { cout <<"\nCommand not found"; } } return 0; }

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• LINQ To SQL Wildcards

  - by mcass20

  How can I build in wildcards to my LINQ To SQL lambda expression? This is what I have currently: var query = from log in context.Logs select log; foreach (string filter in CustomReport.ExtColsToFilter) { string tempFilter = filter; query = query.Where(Log => Log.FormattedMessage.Contains(tempFilter)); } This works fine up until I try and pass wildcards in the filter string. I'm experimenting with SqlMethods.Like() but to no avail. The filters above look like this: "<key>NID</key><value>mcass</value>". I'd like to be able to pass filters like this: "<key>NID</key><value>%m%</value>"

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• Extracting email addresses in an html block in ruby/rails

  - by corroded

  I am creating a parser that wards off against spamming and harvesting of emails from a block of text that comes from tinyMCE (so it may or may not have html tags in it) I've tried regexes and so far this has been successful: /\b[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}\b/i problem is, i need to ignore all email addresses with mailto hrefs. for example: <a href="mailto:[email protected]">[email protected]</a> should only return the second email add. To get a background of what im doing, im reversing the email addresses in a block so the above example would look like this: <a href="mailto:[email protected]">moc.liam@tset</a> problem with my current regex is that it also replaces the one in href. Is there a way for me to do this with a single regex? Or do i have to check for one then the other? Is there a way for me to do this just by using gsub or do I have to use some nokogiri/hpricot magicks and whatnot to parse the mailtos? Thanks in advance! Here were my references btw: so.com/questions/504860/extract-email-addresses-from-a-block-of-text so.com/questions/1376149/regexp-for-extracting-a-mailto-address im also testing using this: http://rubular.com/ edit here's my current helper code: def email_obfuscator(text) text.gsub(/\b[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}\b/i) { |m| m = "<span class='anti-spam'>#{m.reverse}</span>" } end which results in this: <a target="_self" href="mailto:<span class='anti-spam'>moc.liamg@tset</span>"><span class="anti-spam">moc.liamg@tset</span></a>

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• Coding guidelines + Best Practises?

  - by Chathuranga Chandrasekara

  I couldn't find any question that directly applies to my query so I am posting this as a new question. If there is any existing discussion that may help me, please point it out and close the question. Question: I am going to do a presentation on C# coding guidelines but it is not supposed to limit to coding standards. So I have a rough idea but I think I need to address good programing practices. So the contents will be something like this. Basic coding standards - Casing, Formatting etc. Good practices - Usage of Hashset over other data structures, String vs String Builder, String's immutability and using them effectively etc Really I would like to add more good practices (Especially to improve the performance.) So like to hear some more good practices to be used with C#. Any suggestions??? (No need of large descriptions :) Just the idea is sufficient.)

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• How can I do such a typical unittest?

  - by Malcom.Z

  This is a simple structure in my project: MyAPP--- note--- __init__.py views.py urls.py test.py models.py auth-- ... template--- auth--- login.html register.html note--- noteshow.html media--- css--- ... js--- ... settings.py urls.py __init__.py manage.py I want to make a unittest which can test the noteshow page working propeyly or not. The code: from django.test import TestCase class Note(TestCase): def test_noteshow(self): response = self.client.get('/note/') self.assertEqual(response.status_code, 200) self.assertTemplateUsed(response, '/note/noteshow.html') The problem is that my project include an auth mod, it will force the unlogin user redirecting into the login.html page when they visit the noteshow.html. So, when I run my unittest, in the bash it raise an failure that the response.status_code is always 302 instead of 200. All right though through this result I can check the auth mod is running well, it is not like what I want it to be. OK, the question is that how can I make another unittest to check my noteshow.template is used or not? Thanks for all. django version: 1.1.1 python version: 2.6.4 Use Eclipse for MAC OS

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• How do laziness and I/O work together in Haskell?

  - by Bill

  I'm trying to get a deeper understanding of laziness in Haskell. I was imagining the following snippet today: data Image = Image { name :: String, pixels :: String } image :: String -> IO Image image path = Image path <$> readFile path The appeal here is that I could simply create an Image instance and pass it around; if I need the image data it would be read lazily - if not, the time and memory cost of reading the file would be avoided: main = do image <- image "file" putStrLn $ length $ pixels image But is that how it actually works? How is laziness compatible with IO? Will readFile be called regardless of whether I access pixels image or will the runtime leave that thunk unevaluated if I never refer to it? If the image is indeed read lazily, then isn't it possible I/O actions could occur out of order? For example, what if immediately after calling image I delete the file? Now the putStrLn call will find nothing when it tries to read.

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• Factory Method Pattern using Generics-C#

  - by nanda

  Just I am learning Generics.When i have an Abstract Method pattern like : //Abstract Product interface IPage { string pageType(); } //Concerete Product 1 class ResumePage : IPage { public string pageType() { return "Resume Page"; } } //Concrete Product 2 class SummaryPage : IPage { public string pageType() { return "SummaryPage"; } } //Fcatory Creator class FactoryCreator { public IPage CreateOnRequirement(int i) { if (i == 1) return new ResumePage(); else { return new SummaryPage(); } } } //Client/Consumer void Main() { FactoryCreator c = new FactoryCreator(); IPage p; p = c.CreateOnRequirement(1); Console.WriteLine("Page Type is {0}", p.pageType()); p = c.CreateOnRequirement(2); Console.WriteLine("Page Type is {0}", p.pageType()); Console.ReadLine(); } how to convert the code using generics?

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• How to parse strings representing xml.dom.minidom nodes in python?

  - by Francis Davey

  I have a collection of nodes xml.dom.Node objects created using xml.dom.minidom. I store them (individually) in a database by converting them to a string using the toxml() method of a the Node object. The problem is that I'd sometimes like to be able to convert them back to the appropriate Node object using a parser of some kind. As far as I can see the various libraries shipped with python use Expat which won't parse a string like '' or indeed anything which is not a correct xml string. So, does anyone have any ideas? I realise I could pickle the nodes in some way and then unpickle them, but that feels unpleasant and I'd much rather be storing in a form I can read for maintenance purposes. Surely there is something that will do this?

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• Duck type testing with C# 4 for dynamic objects.

  - by Tracker1

  I'm wanting to have a simple duck typing example in C# using dynamic objects. It would seem to me, that a dynamic object should have HasValue/HasProperty/HasMethod methods with a single string parameter for the name of the value, property, or method you are looking for before trying to run against it. I'm trying to avoid try/catch blocks, and deeper reflection if possible. It just seems to be a common practice for duck typing in dynamic languages (JS, Ruby, Python etc.) that is to test for a property/method before trying to use it, then falling back to a default, or throwing a controlled exception. The example below is basically what I want to accomplish. If the methods described above don't exist, does anyone have premade extension methods for dynamic that will do this? Example: In JavaScript I can test for a method on an object fairly easily. //JavaScript function quack(duck) { if (duck && typeof duck.quack === "function") { return duck.quack(); } return null; //nothing to return, not a duck } How would I do the same in C#? //C# 4 dynamic Quack(dynamic duck) { //how do I test that the duck is not null, //and has a quack method? //if it doesn't quack, return null }

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• How to clear a bean field with Stripes.

  - by Davoink

  In a JSP I have the following field: <stripes:text name="email"/> This field is in my action bean(snippet): public class CreateClaim implements ActionBean { private String email; public void setEmail(String email) { this.email = email; } public String getEmail() { return email; } public Resolution alc(){ email = "poodle"; return new ForwardResolution("aForward.jsp"); } } In the alc() methos I am setting email to be null. But when the pages renders the value of the email field is exactly as it was entered originally. Is there a way of clearing this field once and event has triggered? Cheers Dave

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