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  • HTTP Post requests using HttpClient take 2 seconds, why?

    - by pableu
    Update: You might better hold off this for a bit, I just noticed I could be my fault after all. Working on this all afternoon, and then I find a flaw ten minutes after posting here, ts. Hi, I'am currently coding an android app that submits stuff in the background using HTTP Post and AsyncTask. I use the org.apache.http.client Package for this. I based my code on this example. Basically, my code looks like this: public void postData() { // Create a new HttpClient and Post Header HttpClient httpclient = new DefaultHttpClient(); HttpPost httppost = new HttpPost("http://192.168.1.137:8880/form"); try { List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2); nameValuePairs.add(new BasicNameValuePair("id", "12345")); nameValuePairs.add(new BasicNameValuePair("stringdata", "AndDev is Cool!")); httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); // Execute HTTP Post Request HttpResponse response = httpclient.execute(httppost); } catch (ClientProtocolException e) { Log.e(TAG,e.toString()); } catch (IOException e) { Log.e(TAG,e.toString()); } } The problem is that the httpclient.execute(..) line takes around 1.5 to 3 seconds, and I do not understand why. Just requesting a page with HTTP Get takes around 80 ms or so, so the problem doesn't seem to be the network latency itself. The problem doesn't seem to be on the server side either, I have also tried POSTing data to http://www.disney.com/ with similarly slow results. And Firebug shows 1 ms response time when POSTing data to my server locally. This happens on the Emulator and with my Nexus One (both with Android 2.2). If you want to look at the complete code, I've put it on GitHub. It's just a dummy program to do HTTP Post in the background using AsyncTask on the push of a button. It's my first Android app, and my first java code for a long time. And incidentially, also my first question on Stackoverflow ;-) Any ideas why httpclient.execute(httppost) takes so long?

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  • Hibernate Communications Link Failure in Restlet-Hibernate Based Java application powered by MySQL

    - by Vatsala
    Let me describe my question - I have a Java application - Hibernate as the DB interfacing layer over MySQL. I get the communications link failure error in my application. The occurence of this error is a very specific case. I get this error , When I leave mysql server unattended for more than approximately 6 hours (i.e. when there are no queries issued to MySQL for more than approximately 6 hours). I am pasting a top 'exception' level description below, and adding a pastebin link for a detailed stacktrace description. javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: Cannot open connection - Caused by: org.hibernate.exception.JDBCConnectionException: Cannot open connection - Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure - The last packet successfully received from the server was 1,274,868,181,212 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago. - Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure - The last packet successfully received from the server was 1,274,868,181,212 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago. - Caused by: java.net.ConnectException: Connection refused: connect the link to the pastebin for further investigation - http://pastebin.com/4KujAmgD What I understand from these exception statements is that MySQL is refusing to take in any connections after a period of idle/nil activity. I have been reading up a bit about this via google search, and came to know that one of the possible ways to overcome this is to set values for c3p0 properties as c3p0 comes bundled with Hibernate. Specifically, I read from here http://www.mchange.com/projects/c3p0/index.html that setting two properties idleConnectionTestPeriod and preferredTestQuery will solve this for me. But these values dont seem to have had an effect. Is this the correct approach to fixing this? If not, what is the right way to get over this? The following are related Communications Link Failure questions at stackoverflow.com, but I've not found a satisfactory answer in their answers. http://stackoverflow.com/questions/2121829/java-db-communications-link-failure http://stackoverflow.com/questions/298988/how-to-handle-communication-link-failure Note 1 - i dont get this error when I am using my application continuosly. Note 2 - I use JPA with Hibernate and hence my hibernate.dialect,etc hibernate properties reside within the persistence.xml in the META-INF folder (does that prevent the c3p0 properties from working?)

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  • deallocated memory in tableview: message sent to deallocated instance

    - by Kirn
    I tried looking up other issues but couldn't find anything to match so here goes: I'm trying to display text in the table view so I use this bit of code: // StockData is an object I created and it pulls information from Yahoo APIs based on // a stock ticker stored in NSString *heading NSArray* tickerValues = [heading componentsSeparatedByString:@" "]; StockData *chosenStock = [[StockData alloc] initWithContents:[tickerValues objectAtIndex:0]]; [chosenStock getData]; // Set up the cell... NSDictionary *tempDict = [chosenStock values]; NSArray *tempArr = [tempDict allValues]; cell.textLabel.text = [tempArr objectAtIndex:indexPath.row]; return cell; This is all under cellForRowAtIndexPath When I try to release the chosenStock object though I get this error: [CFDictionary release]: message sent to deallocated instance 0x434d3d0 Ive tried using NSZombieEnabled and Build and Analyze to detect problems but no luck thus far. Ive even gone so far as to comment bits and pieces of the code with NSLog but no luck. I'll post the code for StockData below this. As far as I can figure something is getting deallocated before I do the release but I'm not sure how. The only place I've got release in my code is under dealloc method call. Here's the StockData code: // StockData contains all stock information pulled in through Yahoo! to be displayed @implementation StockData @synthesize ticker, values; - (id) initWithContents: (NSString *)newName { if(self = [super init]){ ticker = newName; } return self; } - (void) getData { NSURL *url = [NSURL URLWithString: [NSString stringWithFormat:@"http://download.finance.yahoo.com/d/quotes.csv?s=%@&f=%@&e=.csv", ticker, @"chgvj1"]]; NSError *error; NSURLResponse *response; NSURLRequest *request = [NSURLRequest requestWithURL:url]; NSData *stockData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error]; if(stockData) { NSString *tempStr = [[NSString alloc] initWithData:stockData encoding:NSASCIIStringEncoding]; NSArray *receivedValuesArr = [tempStr componentsSeparatedByString:@","]; [tempStr release]; values = [NSDictionary dictionaryWithObjects:receivedValuesArr forKeys:[@"change, high, low, volume, market" componentsSeparatedByString:@", "]]; } else { NSLog(@"Connection failed: %@", error); } } - (void)dealloc { [ticker release]; [values release]; [super dealloc]; NSLog(@"Release took place fine"); } @end

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  • Template function as a template argument

    - by Kos
    I've just got confused how to implement something in a generic way in C++. It's a bit convoluted, so let me explain step by step. Consider such code: void a(int) { // do something } void b(int) { // something else } void function1() { a(123); a(456); } void function2() { b(123); b(456); } void test() { function1(); function2(); } It's easily noticable that function1 and function2 do the same, with the only different part being the internal function. Therefore, I want to make function generic to avoid code redundancy. I can do it using function pointers or templates. Let me choose the latter for now. My thinking is that it's better since the compiler will surely be able to inline the functions - am I correct? Can compilers still inline the calls if they are made via function pointers? This is a side-question. OK, back to the original point... A solution with templates: void a(int) { // do something } void b(int) { // something else } template<void (*param)(int) > void function() { param(123); param(456); } void test() { function<a>(); function<b>(); } All OK. But I'm running into a problem: Can I still do that if a and b are generics themselves? template<typename T> void a(T t) { // do something } template<typename T> void b(T t) { // something else } template< ...param... > // ??? void function() { param<SomeType>(someobj); param<AnotherType>(someotherobj); } void test() { function<a>(); function<b>(); } I know that a template parameter can be one of: a type, a template type, a value of a type. None of those seems to cover my situation. My main question is hence: How do I solve that, i.e. define function() in the last example? (Yes, function pointers seem to be a workaround in this exact case - provided they can also be inlined - but I'm looking for a general solution for this class of problems).

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  • Android - exception from an AsynchTask call

    - by GeekedOut
    I have an Activity that makes a remote server call and tries to populate a list. The call to the server works fine, and the call returns some JSON which is good. But then the system throws this exception: 04-06 18:43:19.626: D/AndroidRuntime(2564): Shutting down VM 04-06 18:43:19.626: W/dalvikvm(2564): threadid=1: thread exiting with uncaught exception (group=0x409c01f8) 04-06 18:43:19.686: E/AndroidRuntime(2564): FATAL EXCEPTION: main 04-06 18:43:19.686: E/AndroidRuntime(2564): java.lang.NullPointerException 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:394) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.AbsListView.obtainView(AbsListView.java:2033) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.ListView.measureHeightOfChildren(ListView.java:1244) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.ListView.onMeasure(ListView.java:1155) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.view.View.measure(View.java:12723) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1369) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.LinearLayout.measureVertical(LinearLayout.java:660) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.LinearLayout.onMeasure(LinearLayout.java:553) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.view.View.measure(View.java:12723) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.FrameLayout.onMeasure(FrameLayout.java:293) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.view.View.measure(View.java:12723) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.LinearLayout.measureVertical(LinearLayout.java:812) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.LinearLayout.onMeasure(LinearLayout.java:553) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.view.View.measure(View.java:12723) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.widget.FrameLayout.onMeasure(FrameLayout.java:293) 04-06 18:43:19.686: E/AndroidRuntime(2564): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2092) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.view.View.measure(View.java:12723) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1064) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.os.Handler.dispatchMessage(Handler.java:99) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.os.Looper.loop(Looper.java:137) 04-06 18:43:19.686: E/AndroidRuntime(2564): at android.app.ActivityThread.main(ActivityThread.java:4424) 04-06 18:43:19.686: E/AndroidRuntime(2564): at java.lang.reflect.Method.invokeNative(Native Method) 04-06 18:43:19.686: E/AndroidRuntime(2564): at java.lang.reflect.Method.invoke(Method.java:511) 04-06 18:43:19.686: E/AndroidRuntime(2564): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 04-06 18:43:19.686: E/AndroidRuntime(2564): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 04-06 18:43:19.686: E/AndroidRuntime(2564): at dalvik.system.NativeStart.main(Native Method) Why would this happen? It doesn't point to any of my code so its a bit strange. the protected void onPostExecute(String result) never gets called on the callback. Thanks!

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  • Why do sockets not die when server dies? Why does a socket die when server is alive?

    - by Roman
    I try to play with sockets a bit. For that I wrote very simple "client" and "server" applications. Client: import java.net.*; public class client { public static void main(String[] args) throws Exception { InetAddress localhost = InetAddress.getLocalHost(); System.out.println("before"); Socket clientSideSocket = null; try { clientSideSocket = new Socket(localhost,12345,localhost,54321); } catch (ConnectException e) { System.out.println("Connection Refused"); } System.out.println("after"); if (clientSideSocket != null) { clientSideSocket.close(); } } } Server: import java.net.*; public class server { public static void main(String[] args) throws Exception { ServerSocket listener = new ServerSocket(12345); while (true) { Socket serverSideSocket = listener.accept(); System.out.println("A client-request is accepted."); } } } And I found a behavior that I cannot explain: I start a server, than I start a client. Connection is successfully established (client stops running and server is running). Then I close the server and start it again in a second. After that I start a client and it writes "Connection Refused". It seems to me that the server "remember" the old connection and does not want to open the second connection twice. But I do not understand how it is possible. Because I killed the previous server and started a new one! I do not start the server immediately after the previous one was killed (I wait like 20 seconds). In this case the server "forget" the socket from the previous server and accepts the request from the client. I start the server and then I start the client. Connection is established (server writes: "A client-request is accepted"). Then I wait a minute and start the client again. And server (which was running the whole time) accept the request again! Why? The server should not accept the request from the same client-IP and client-port but it does!

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  • Problems Enforcing Referential Integrity on SQL Server Tables

    - by SidC
    Hello All, I have a SQL Server 2005 database comprised of Customer, Quote, QuoteDetail tables. I want/need to enforce referential integrity such that when an insert is made on quotedetail, the quote and customer tables are also affected. I have tried my best to set up primary/foreign keys on my tables but need some help. Here's the scripts for my tables as they stand now (please don't laugh): Customers: USE [Diel_inventory] GO /****** Object: Table [dbo].[Customers] Script Date: 05/08/2010 03:39:04 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[Customers]( [pkCustID] [int] IDENTITY(1,1) NOT NULL, [CompanyName] [nvarchar](50) NULL, [Address] [nvarchar](50) NULL, [City] [nvarchar](50) NULL, [State] [nvarchar](2) NULL, [ZipCode] [nvarchar](5) NULL, [OfficePhone] [nvarchar](12) NULL, [OfficeFAX] [nvarchar](12) NULL, [Email] [nvarchar](50) NULL, [PrimaryContactName] [nvarchar](50) NULL, CONSTRAINT [PK_Customers] PRIMARY KEY CLUSTERED ([pkCustID] ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] Quotes: USE [Diel_inventory] GO /****** Object: Table [dbo].[Quotes] Script Date: 05/08/2010 03:30:46 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[Quotes]( [pkQuoteID] [int] IDENTITY(1,1) NOT NULL, [fkCustomerID] [int] NOT NULL, [QuoteDate] [timestamp] NOT NULL, [NeedbyDate] [datetime] NULL, [QuoteAmt] [decimal](6, 2) NOT NULL, [QuoteApproved] [bit] NOT NULL, [fkOrderID] [int] NOT NULL, CONSTRAINT [PK_Bids] PRIMARY KEY CLUSTERED ( [pkQuoteID] ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO ALTER TABLE [dbo].[Quotes] WITH CHECK ADD CONSTRAINT [fkCustomerID] FOREIGN KEY([fkCustomerID]) REFERENCES [dbo].[Customers] ([pkCustID]) GO ALTER TABLE [dbo].[Quotes] CHECK CONSTRAINT [fkCustomerID] QuoteDetail: USE [Diel_inventory] GO /****** Object: Table [dbo].[QuoteDetail] Script Date: 05/08/2010 03:31:58 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[QuoteDetail]( [ID] [int] IDENTITY(1,1) NOT NULL, [fkQuoteID] [int] NOT NULL, [fkCustomerID] [int] NOT NULL, [fkPartID] [int] NULL, [PartNumber1] [float] NOT NULL, [Qty1] [int] NOT NULL, [PartNumber2] [float] NULL, [Qty2] [int] NULL, [PartNumber3] [float] NULL, [Qty3] [int] NULL, [PartNumber4] [float] NULL, [Qty4] [int] NULL, [PartNumber5] [float] NULL, [Qty5] [int] NULL, [PartNumber6] [float] NULL, [Qty6] [int] NULL, [PartNumber7] [float] NULL, [Qty7] [int] NULL, [PartNumber8] [float] NULL, [Qty8] [int] NULL, [PartNumber9] [float] NULL, [Qty9] [int] NULL, [PartNumber10] [float] NULL, [Qty10] [int] NULL, [PartNumber11] [float] NULL, [Qty11] [int] NULL, [PartNumber12] [float] NULL, [Qty12] [int] NULL, [PartNumber13] [float] NULL, [Qty13] [int] NULL, [PartNumber14] [float] NULL, [Qty14] [int] NULL, [PartNumber15] [float] NULL, [Qty15] [int] NULL, [PartNumber16] [float] NULL, [Qty16] [int] NULL, [PartNumber17] [float] NULL, [Qty17] [int] NULL, [PartNumber18] [float] NULL, [Qty18] [int] NULL, [PartNumber19] [float] NULL, [Qty19] [int] NULL, [PartNumber20] [float] NULL, [Qty20] [int] NULL, CONSTRAINT [PK_QuoteDetail] PRIMARY KEY CLUSTERED ( [ID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO ALTER TABLE [dbo].[QuoteDetail] WITH CHECK ADD CONSTRAINT [FK_QuoteDetail_Customers] FOREIGN KEY ([fkCustomerID]) REFERENCES [dbo].[Customers] ([pkCustID]) GO ALTER TABLE [dbo].[QuoteDetail] CHECK CONSTRAINT [FK_QuoteDetail_Customers] GO ALTER TABLE [dbo].[QuoteDetail] WITH CHECK ADD CONSTRAINT [FK_QuoteDetail_PartList] FOREIGN KEY ([fkPartID]) REFERENCES [dbo].[PartList] ([RecID]) GO ALTER TABLE [dbo].[QuoteDetail] CHECK CONSTRAINT [FK_QuoteDetail_PartList] GO ALTER TABLE [dbo].[QuoteDetail] WITH CHECK ADD CONSTRAINT [FK_QuoteDetail_Quotes] FOREIGN KEY([fkQuoteID]) REFERENCES [dbo].[Quotes] ([pkQuoteID]) GO ALTER TABLE [dbo].[QuoteDetail] CHECK CONSTRAINT [FK_QuoteDetail_Quotes] Your advice/guidance on how to set these up so that customer ID in Customers is the same as in Quotes (referential integrity) and that CustomerID is inserted on Quotes and Customers when an insert is made to QuoteDetial would be much appreciated. Thanks, Sid

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  • Does this incorporate JavaScript closures?

    - by alex
    In trying to learn JavaScript closures, I've confused myself a bit. From what I've gathered over the web, a closure is... Declaring a function within another function, and that inner function has access to its parent function's variables, even after that parent function has returned. Here is a small sample of script from a recent project. It allows text in a div to be scrolled up and down by buttons. var pageScroll = (function() { var $page, $next, $prev, canScroll = true, textHeight, scrollHeight; var init = function() { $page = $('#secondary-page'); // reset text $page.scrollTop(0); textHeight = $page.outerHeight(); scrollHeight = $page.attr('scrollHeight'); if (textHeight === scrollHeight) { // not enough text to scroll return false; }; $page.after('<div id="page-controls"><button id="page-prev">prev</button><button id="page-next">next</button></div>'); $next = $('#page-next'); $prev = $('#page-prev'); $prev.hide(); $next.click(scrollDown); $prev.click(scrollUp); }; var scrollDown = function() { if ( ! canScroll) return; canScroll = false; var scrollTop = $page.scrollTop(); $prev.fadeIn(500); if (scrollTop == textHeight) { // can we scroll any lower? $next.fadeOut(500); } $page.animate({ scrollTop: '+=' + textHeight + 'px'}, 500, function() { canScroll = true; }); }; var scrollUp = function() { $next.fadeIn(500); $prev.fadeOut(500); $page.animate({ scrollTop: 0}, 500); }; $(document).ready(init); }()); Does this example use closures? I know it has functions within functions, but is there a case where the outer variables being preserved is being used? Am I using them without knowing it? Thanks Update Would this make a closure if I placed this beneath the $(document).ready(init); statement? return { scrollDown: scrollDown }; Could it then be, if I wanted to make the text scroll down from anywhere else in JavaScript, I could do pageScroll.scrollDown(); I'm going to have a play around on http://www.jsbin.com and report back

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  • Strategies for "Always-Connected" Windows Client Data Architecture

    - by magz2010
    Hi. Let me start by saying: this is my 1st post here, this is a bit lenghty, and I havent done Windows Forms development in years....with that in mind please excuse me if this isn't directly a programming question and please bear with me as I really need the help!! I have been asked to develop a Windows Forms app for our company that talks to a central (local area network) Linux Server hosting a PostgreSQL database. The app is to allow users to authenticate themselves into the system and thereafter conduct the usual transactions with the PG database. Ordinarily, I would propose writing a webforms app against Mono, but the clients need to utilise local resources such as USB peripheral devices, so that is out of the question. While it might not seem clear, my questions are italised below: Dilemma #1: The application is meant to be always connected. How should I structure my DAL/BLL - Should this reside on the server or with the client? Dilemma #2: I have been reading up on Client Application Services (CAS), and it seems like a great fit for authentication, as everything is exposed via URIs. I know that a .NET Data Provider exists for PostgreSQL, but not too sure if CAS will all work on a Linux (Debian) server? Believe me, I would get my hands dirty and try myself, but I need to come up with a logical design first before resources are allocated to me for "trial purposes"! Dilemma #3: If the DAL/BLL is to reside on the server, is there any way I can create data services, and expose only these services to authenticated clients. There is a (security) requirement whereby a connection string with username and password to the database cannot be present on any client machines...even if security on the database side is quite rigid. I'm guessing that the only way for this to work would be to create the various CRUD data service methods that are exposed by an ASP.NET app, and have the WindowsForms make a request for data or persist data to the ASP.NET app (thru a URI) and have that return a resultset or value. Would I be correct in assuming this? Should I be looking into WCF Data Services? and will WCF work with a non-SQL Server database? Thank you for taking the time out to read this, but know that I am desperately seeking any advice on this! THANKS A MILLION!!!!

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  • Which MS technologies would be suited for a data intensive application?

    - by steve.tse
    I'm a junior VB.net developer with little application design knowledge. I've been reading a lot of material online regarding different design patterns, frameworks, and methodologies. It's become a bit confusing for me. Right now I'm trying to decide on what language would be best suited to convert an existing VB6 application (with SQL server backend.) I need to update the UI and add more user functionality and reporting capabilities. Initially I was thinking of using WPF and attempting the MVVM model for this big project. Reports would be generated from SSRS. A peer suggested using ASP.net and I don't have enough experience to determine what would be better. The senior programmers here are stuck on using VB6 and don't have any input on what to use. They are encouraging me to use the latest technologies. This application would be for ~20 users in a central location. Ideally I would stick to a Microsoft .net language. Current interface is similar to a datagrid table where the user would click in to see the detail of each record. They would need to have multiple records open at any given time. I look forward to all the advice I can get. EDIT 2010/04/22 2:47 PM EST What is your audience? Internal clients within an intranet How complex are the interactions you expect to implement? not very... displaying data from SQL server to UI. Allow user updates to said data. Typically just one user modifying a record. Do you require near real-time data updates? no How often do you expect to update the application after the first release? twice/year Do you expect a well-defined set of client platforms? Yes, windows xp environment, potentially upgrading to Win7. Currently in IE.6 moving to IE7 or 8 within a couple of months. Do users need access from anywhere? No, just from their PC.

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  • How to Convert arrays or SimpleXML-Objects into an XML-String

    - by streetparade
    I want to create a xml from a given string, i have a function but i didn't wrote it.It seems a bit cryptical too. Can please some one review it and give me some Ideas, how it could be written clearer for everybody? /** * Converts arrays or SimpleXML-Objects into an XML-String * @params mixed Accepts an array or xml string with data to Post * @params integer DO NOT PROVIDE. Internal Usage for recursion only */ private function mixedDataToXML($data, $level = 1) { if(!$data){ return FALSE; } if(is_array($data)) { $xml = ''; if ($level==1) { $xml .= '<?xml version="1.0" encoding="ISO-8859-1"?>'."\n"; } foreach ($data as $key => $value) { $key = strtolower($key); if (is_array($value)) { $multi_tags = false; foreach($value as $key2=>$value2) { if (is_array($value2)) { $xml .= str_repeat("\t",$level)."<$key>\n"; $xml .= $this->mixedDataToXML($value2, $level+1); $xml .= str_repeat("\t",$level)."</$key>\n"; $multi_tags = true; } else { if (trim($value2)!='') { if (htmlspecialchars($value2)!=$value2) { $xml .= str_repeat("\t",$level). "<$key><![CDATA[$value2]]>". "</$key>\n"; } else { $xml .= str_repeat("\t",$level). "<$key>$value2</$key>\n"; } } $multi_tags = true; } } if (!$multi_tags and count($value)>0) { $xml .= str_repeat("\t",$level)."<$key>\n"; $xml .= $this->mixedDataToXML($value, $level+1); $xml .= str_repeat("\t",$level)."</$key>\n"; } } else { if (trim($value)!='') { if (htmlspecialchars($value)!=$value) { $xml .= str_repeat("\t",$level)."<$key>". "<![CDATA[$value]]></$key>\n"; } else { $xml .= str_repeat("\t",$level). "<$key>$value</$key>\n"; } } } } return $xml; }else{ return (string)$data; } }

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  • Converting C source to C++

    - by Barry Kelly
    How would you go about converting a reasonably large (300K), fairly mature C codebase to C++? The kind of C I have in mind is split into files roughly corresponding to modules (i.e. less granular than a typical OO class-based decomposition), using internal linkage in lieu private functions and data, and external linkage for public functions and data. Global variables are used extensively for communication between the modules. There is a very extensive integration test suite available, but no unit (i.e. module) level tests. I have in mind a general strategy: Compile everything in C++'s C subset and get that working. Convert modules into huge classes, so that all the cross-references are scoped by a class name, but leaving all functions and data as static members, and get that working. Convert huge classes into instances with appropriate constructors and initialized cross-references; replace static member accesses with indirect accesses as appropriate; and get that working. Now, approach the project as an ill-factored OO application, and write unit tests where dependencies are tractable, and decompose into separate classes where they are not; the goal here would be to move from one working program to another at each transformation. Obviously, this would be quite a bit of work. Are there any case studies / war stories out there on this kind of translation? Alternative strategies? Other useful advice? Note 1: the program is a compiler, and probably millions of other programs rely on its behaviour not changing, so wholesale rewriting is pretty much not an option. Note 2: the source is nearly 20 years old, and has perhaps 30% code churn (lines modified + added / previous total lines) per year. It is heavily maintained and extended, in other words. Thus, one of the goals would be to increase mantainability. [For the sake of the question, assume that translation into C++ is mandatory, and that leaving it in C is not an option. The point of adding this condition is to weed out the "leave it in C" answers.]

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  • Combining FileStream and MemoryStream to avoid disk accesses/paging while receiving gigabytes of data?

    - by w128
    I'm receiving a file as a stream of byte[] data packets (total size isn't known in advance) that I need to store somewhere before processing it immediately after it's been received (I can't do the processing on the fly). Total received file size can vary from as small as 10 KB to over 4 GB. One option for storing the received data is to use a MemoryStream, i.e. a sequence of MemoryStream.Write(bufferReceived, 0, count) calls to store the received packets. This is very simple, but obviously will result in out of memory exception for large files. An alternative option is to use a FileStream, i.e. FileStream.Write(bufferReceived, 0, count). This way, no out of memory exceptions will occur, but what I'm unsure about is bad performance due to disk writes (which I don't want to occur as long as plenty of memory is still available) - I'd like to avoid disk access as much as possible, but I don't know of a way to control this. I did some testing and most of the time, there seems to be little performance difference between say 10 000 consecutive calls of MemoryStream.Write() vs FileStream.Write(), but a lot seems to depend on buffer size and the total amount of data in question (i.e the number of writes). Obviously, MemoryStream size reallocation is also a factor. Does it make sense to use a combination of MemoryStream and FileStream, i.e. write to memory stream by default, but once the total amount of data received is over e.g. 500 MB, write it to FileStream; then, read in chunks from both streams for processing the received data (first process 500 MB from the MemoryStream, dispose it, then read from FileStream)? Another solution is to use a custom memory stream implementation that doesn't require continuous address space for internal array allocation (i.e. a linked list of memory streams); this way, at least on 64-bit environments, out of memory exceptions should no longer be an issue. Con: extra work, more room for mistakes. So how do FileStream vs MemoryStream read/writes behave in terms of disk access and memory caching, i.e. data size/performance balance. I would expect that as long as enough RAM is available, FileStream would internally read/write from memory (cache) anyway, and virtual memory would take care of the rest. But I don't know how often FileStream will explicitly access a disk when being written to. Any help would be appreciated.

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  • thread management in nbody code of cuda-sdk

    - by xnov
    When I read the nbody code in Cuda-SDK, I went through some lines in the code and I found that it is a little bit different than their paper in GPUGems3 "Fast N-Body Simulation with CUDA". My questions are: First, why the blockIdx.x is still involved in loading memory from global to share memory as written in the following code? for (int tile = blockIdx.y; tile < numTiles + blockIdx.y; tile++) { sharedPos[threadIdx.x+blockDim.x*threadIdx.y] = multithreadBodies ? positions[WRAP(blockIdx.x + q * tile + threadIdx.y, gridDim.x) * p + threadIdx.x] : //this line positions[WRAP(blockIdx.x + tile, gridDim.x) * p + threadIdx.x]; //this line __syncthreads(); // This is the "tile_calculation" function from the GPUG3 article. acc = gravitation(bodyPos, acc); __syncthreads(); } isn't it supposed to be like this according to paper? I wonder why sharedPos[threadIdx.x+blockDim.x*threadIdx.y] = multithreadBodies ? positions[WRAP(q * tile + threadIdx.y, gridDim.x) * p + threadIdx.x] : positions[WRAP(tile, gridDim.x) * p + threadIdx.x]; Second, in the multiple threads per body why the threadIdx.x is still involved? Isn't it supposed to be a fix value or not involving at all because the sum only due to threadIdx.y if (multithreadBodies) { SX_SUM(threadIdx.x, threadIdx.y).x = acc.x; //this line SX_SUM(threadIdx.x, threadIdx.y).y = acc.y; //this line SX_SUM(threadIdx.x, threadIdx.y).z = acc.z; //this line __syncthreads(); // Save the result in global memory for the integration step if (threadIdx.y == 0) { for (int i = 1; i < blockDim.y; i++) { acc.x += SX_SUM(threadIdx.x,i).x; //this line acc.y += SX_SUM(threadIdx.x,i).y; //this line acc.z += SX_SUM(threadIdx.x,i).z; //this line } } } Can anyone explain this to me? Is it some kind of optimization for faster code?

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  • Web SITE publishing, dynamic compilation, smoke & mirrors

    - by tbehunin
    When you publish a web SITE in Visual Studio, in the dialog box that follows, you are given an option to "Allow this precompiled site to be updatable". According to MSDN, checking this option "specifies that all program code is compiled into assemblies, but that .aspx files (including single-file ASP.NET Web pages) are copied as-is to the target folder". With this option checked, you can update existing .aspx files as well as add new ones without any issue. When a page, that has either been updated or newly created, is requested, the page gets dynamically compiled at run-time and is then processed and returned to the user. If, on the other hand, you didn't check that checkbox during the publish phase, the .aspx files get compiled, along with the code-behind and App_Code files in separate assemblies. The .aspx files are then completely overwritten with a line of text that says: This is a marker file generated by the precompilation tool, and should not be deleted! You obviously can't edit an existing page in this scenario. If you were to ADD a new .aspx file to this site, you would get a .Net run-time error saying that the file hasn't been precompiled. With that background, my questions are these: Something must be able to determine that this website was published to be updatable (allow dynamic compilation) or not. If it was published as updatable, it must also be able to determine whether a file was changed or added, so it can do a dynamic compile. Who makes those determinations? IIS? ASP.NET worker process? HOW does it make those determinations? If I had the same website published in both of those scenarios, could I make a visual determination that one is updatable and the other is not? Is there some bit I can look at in the assemblies using Reflector to make that determination myself? In addition to answering those questions, what also might be helpful would be information on the process flow from when a resource is requested to when it starts being processed, not necessarily the ASP.NET Page Lifecycle, but what happens BEFORE ASP.Net worker process starts processing the page and firing off events. The dynamic compilation appears to be smoke and mirrors. Can someone demystify this for me?

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  • Wordpress installed in root folder, subdomain now not working, GoDaddy host

    - by Kristin
    Hi, please forgive me for being a complete beginner at this, I'd rather not have to try to deal with this myself but as GoDaddy support have not replied after 2 days I'm going to have to. I think my problem is the same as the one above, but I'm not 100% sure, so I'm reposting it, I'm not really confident enough to attempt to try the fixes I've seen here so I need someone to give me baby instructions? Our original website (www.mwpics.com.au) was built in Dreamweaver etc, recently we created a new website in Wordpress, in a subdomain, then migrated it over to the root folder where it is now operating fine. I also moved the files for the old website into another directory which I called 'old', so they're all still there. The problem is that I have a subdomain set up - which is still showing as set up in the control panel on godaddy the url is www.mwpics.com.au/clients and it is at www.clients.mwpics.com.au. This directory contains loads of other directories, each of which is password protected by .htaccess files and which our clients access directly (not through the site) to download their finished work. The test one and the one for random clients is www.mwpics.com.au/clients/temp - username and password both temp (the usernames are all the same as the directory names). Since the WP install to the root directory the /clients extension no longer works (it should bring up an information page which is an .html index page in the directory) and the /clients/name extensions no longer works - it goes back to the wp site with a 'not found' error message. Strangely it does bring up the box for the username and password, but when you enter it it just goes back to the 'not found' message. Someone told me it was the .htaccess file - so as an experiment, I renamed the .htaccess file in the root directory and then copied the .htaccess file from the old root files into the root directory, eureka! It worked - and also the WP site opened to the home page... but bummer - the /pages in the WP site now no longer worked! But at least I know the source of the problem. So I switched it back and this is the status quo - I have no idea how to fix this, and with everyone back at work tomorrow, clients are going to want to start downloading their stuff... Can anyone help me? I'm starting to panic a bit

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  • Asp.net web service: Problems accessing without www

    - by MysterM
    I have a Asp.net web service running on www.domain.com/Service.svc that I connect to using jQuery from my asp.net website. Everything works perfect if the user access my website with www.domain.com. But if the user uses only domain.com I get error: There was no channel actively listening at 'http://domain.com/Service.svc/get?date=2010-10-09'. This is often caused by an incorrect address URI. Ensure that the address to which the message is sent matches an address on which a service is listening. In my web.config I use the serviceHostingEnvironment tag to get the service running on my webhost (it doesn't work otherwise). Maybe this is what causes the error? Here is my system.serviceModel in web.config (I had some problems setting up the web service so that's why my web.config might be a bit messy: <system.serviceModel> <behaviors> <endpointBehaviors> <behavior name="ServiceAspNetAjaxBehavior"> <enableWebScript /> </behavior> </endpointBehaviors> <serviceBehaviors> <behavior name="ServiceBehavior"> <serviceDebug includeExceptionDetailInFaults="true" /> </behavior> </serviceBehaviors> </behaviors> <serviceHostingEnvironment aspNetCompatibilityEnabled="true"> <baseAddressPrefixFilters> <add prefix="http://www.domain.com"/> </baseAddressPrefixFilters> </serviceHostingEnvironment> <services> <service behaviorConfiguration="ServiceBehavior" name="Service"> <endpoint address="" behaviorConfiguration="ServiceAspNetAjaxBehavior" binding="webHttpBinding" bindingConfiguration="ServiceBinding" contract="Service" /> </service> </services> <bindings> <webHttpBinding> <binding name="ServiceBinding" maxBufferPoolSize="1000000" maxReceivedMessageSize="1000000"> <readerQuotas maxDepth="1000000" maxStringContentLength="1000000" maxArrayLength="1000000" maxBytesPerRead="1000000" maxNameTableCharCount="1000000" /> </binding> </webHttpBinding> </bindings> </system.serviceModel> How can I make it possible for my users to access my webservice also when using only domain.com?

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  • git: setting a single tracking remote from a public repo.

    - by Gauthier
    I am confused with remote branches. My local repo: (local) ---A---B---C-master My remote repo (called int): (int) ---A---B---C---D---E-master What I want to do is to setup the local repo's master branch to follow that of int. Local repo: (local) ---A---B---C---D---E-master-remotes/int/master So that when int changes to: (int) ---A---B---C---D---E---F-master I can run git pull from the local repo's master and get (local) ---A---B---C---D---E---F-master-remotes/int/master Here's what I have tried: git fetch int gets me all the branches of int into remote branches. This can get messy since int might have hundreds of branches. git fetch int master gets me the commits, but no ref to it, only FETCH_HEAD. No remote branch either. git fetch int master:new_master works but I don't want a new name every time I update, and no remote branch is setup. git pull int master does what I want, but there is still no remote branch setup. I feel that it is ok to do so (that's the best I have now), but I read here and there that with the remote setup it is enough with git pull. git branch --track new_master int/master, as per http://www.gitready.com/beginner/2009/03/09/remote-tracking-branches.html . I get "not a valid object name: int/master". git remote -v does show me that int is defined and points at the correct location (1. worked). What I miss is the int/master branch, which is precisely what I want to get. git fetch in master:int/master. Well, int/master is created, but is no remote. So to summarize, I've tried some stuff with no luck. I would expect 2 to give me the remote branch to master in the repo int. The solution I use now is option 3. I read somewhere that you could change some config file by hand, but isn't that a bit cumbersome? The "cumbersome" way of editting the config file did work: [branch "master"] remote = int merge = master It can be done from command line: $ git config branch.master.remote int $ git config branch.master.merge master Any reason why option 2 above wouldn't do that automatically? Even in that case, git pull fetches all branches from the remote.

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  • How can I improve the recursion capabilities of my ECMAScript implementation?

    - by ChaosPandion
    After some resent tests I have found my implementation cannot handle very much recursion. Although after I ran a few tests in Firefox I found that this may be more common than I originally thought. I believe the basic problem is that my implementation requires 3 calls to make a function call. The first call is made to a method named Call that makes sure the call is being made to a callable object and gets the value of any arguments that are references. The second call is made to a method named Call which is defined in the ICallable interface. This method creates the new execution context and builds the lambda expression if it has not been created. The final call is made to the lambda that the function object encapsulates. Clearly making a function call is quite heavy but I am sure that with a little bit of tweaking I can make recursion a viable tool when using this implementation. public static object Call(ExecutionContext context, object value, object[] args) { var func = Reference.GetValue(value) as ICallable; if (func == null) { throw new TypeException(); } if (args != null && args.Length > 0) { for (int i = 0; i < args.Length; i++) { args[i] = Reference.GetValue(args[i]); } } var reference = value as Reference; if (reference != null) { if (reference.IsProperty) { return func.Call(reference.Value, args); } else { return func.Call(((EnviromentRecord)reference.Value).ImplicitThisValue(), args); } } return func.Call(Undefined.Value, args); } public object Call(object thisObject, object[] arguments) { var lexicalEnviroment = Scope.NewDeclarativeEnviroment(); var variableEnviroment = Scope.NewDeclarativeEnviroment(); var thisBinding = thisObject ?? Engine.GlobalEnviroment.GlobalObject; var newContext = new ExecutionContext(Engine, lexicalEnviroment, variableEnviroment, thisBinding); Engine.EnterContext(newContext); var result = Function.Value(newContext, arguments); Engine.LeaveContext(); return result; }

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  • Trying to run multiple HTTP requests in parallel, but being limited by Windows (registry)

    - by Nailuj
    I'm developing an application (winforms C# .NET 4.0) where I access a lookup functionality from a 3rd party through a simple HTTP request. I call an url with a parameter, and in return I get a small string with the result of the lookup. Simple enough. The challenge is however, that I have to do lots of these lookups (a couple of thousands), and I would like to limit the time needed. Therefore I would like to run requests in parallel (say 10-20). I use a ThreadPool to do this, and the short version of my code looks like this: public void startAsyncLookup(Action<LookupResult> returnLookupResult) { this.returnLookupResult = returnLookupResult; foreach (string number in numbersToLookup) { ThreadPool.QueueUserWorkItem(lookupNumber, number); } } public void lookupNumber(Object threadContext) { string numberToLookup = (string)threadContext; string url = @"http://some.url.com/?number=" + numberToLookup; WebClient webClient = new WebClient(); Stream responseData = webClient.OpenRead(url); LookupResult lookupResult = parseLookupResult(responseData); returnLookupResult(lookupResult); } I fill up numbersToLookup (a List<String>) from another place, call startAsyncLookup and provide it with a call-back function returnLookupResult to return each result. This works, but I found that I'm not getting the throughput I want. Initially I thought it might be the 3rd party having a poor system on their end, but I excluded this by trying to run the same code from two different machines at the same time. Each of the two took as long as one did alone, so I could rule out that one. A colleague then tipped me that this might be a limitation in Windows. I googled a bit, and found amongst others this post saying that by default Windows limits the number of simultaneous request to the same web server to 4 for HTTP 1.0 and to 2 for HTTP 1.1 (for HTTP 1.1 this is actually according to the specification (RFC2068)). The same post referred to above also provided a way to increase these limits. By adding two registry values to [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings] (MaxConnectionsPerServer and MaxConnectionsPer1_0Server), I could control this myself. So, I tried this (sat both to 20), restarted my computer, and tried to run my program again. Sadly though, it didn't seem to help any. I also kept an eye on the Resource Monitor (see screen shot) while running my batch lookup, and I noticed that my application (the one with the title blacked out) still only was using two TCP connections. So, the question is, why isn't this working? Is the post I linked to using the wrong registry values? Is this perhaps not possible to "hack" in Windows any longer (I'm on Windows 7)? Any ideas would be highly appreciated :) And just in case anyone should wonder, I have also tried with different settings for MaxThreads on ThreadPool (everyting from 10 to 100), and this didn't seem to affect my throughput at all, so the problem shouldn't be there either.

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  • Getting key/value pairs from plist-style xml using simplexml in php

    - by Anthony
    Here is an example bit from the xml file: <array> <dict> <key>Name</key> <string>Joe Smith</string> <key>Type</key> <string>Profile</string> <key>Role</key> <string>User</string> <key>Some Number</key> <integer>1</integer> <key>Some Boolean</key> <true/> </dict> </array> I have two separate goals. The first is to extract an array from the dictnode that would look like: [Name] => Joe Smith [Type] => Profile [Role] => User [Some Number] => 1 [Some Boolean] => true It's not crucial that the boolean be included, so if that adds too much complexity, I'd rather just know how to deal with the others for now. The second goal is to be able to select the value node (<string>, <integer>,etc) so that I can change the value. I would need to select it based on the text value of the preceding key element. I think the following XPath should work: //key[.=$keyname]/following-sibling[1] But I'm not sure. Basically, this whole system that Apple uses seems logical, but totally contrary to the XML is supposed to work. If I ran the world, the original XML would look more like: <dict type="array"> <value key="Name" type="string">Joe Smith</value> <value key="Type" type="string">Profile</value> <value key="Role type="string">User</value> <value key="Some Number" type="integer">1</value> <value key="Some Boolean" type="boolean">true</value> </dict> But since it is fairly logical, I am wondering if I'm missing some obvious way of handling it.

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  • How do you unit test the real world?

    - by Kim Sun-wu
    I'm primarily a C++ coder, and thus far, have managed without really writing tests for all of my code. I've decided this is a Bad Idea(tm), after adding new features that subtly broke old features, or, depending on how you wish to look at it, introduced some new "features" of their own. But, unit testing seems to be an extremely brittle mechanism. You can test for something in "perfect" conditions, but you don't get to see how your code performs when stuff breaks. A for instance is a crawler, let's say it crawls a few specific sites, for data X. Do you simply save sample pages, test against those, and hope that the sites never change? This would work fine as regression tests, but, what sort of tests would you write to constantly check those sites live and let you know when the application isn't doing it's job because the site changed something, that now causes your application to crash? Wouldn't you want your test suite to monitor the intent of the code? The above example is a bit contrived, and something I haven't run into (in case you haven't guessed). Let me pick something I have, though. How do you test an application will do its job in the face of a degraded network stack? That is, say you have a moderate amount of packet loss, for one reason or the other, and you have a function DoSomethingOverTheNetwork() which is supposed to degrade gracefully when the stack isn't performing as it's supposed to; but does it? The developer tests it personally by purposely setting up a gateway that drops packets to simulate a bad network when he first writes it. A few months later, someone checks in some code that modifies something subtly, so the degradation isn't detected in time, or, the application doesn't even recognize the degradation, this is never caught, because you can't run real world tests like this using unit tests, can you? Further, how about file corruption? Let's say you're storing a list of servers in a file, and the checksum looks okay, but the data isn't really. You want the code to handle that, you write some code that you think does that. How do you test that it does exactly that for the life of the application? Can you? Hence, brittleness. Unit tests seem to test the code only in perfect conditions(and this is promoted, with mock objects and such), not what they'll face in the wild. Don't get me wrong, I think unit tests are great, but a test suite composed only of them seems to be a smart way to introduce subtle bugs in your code while feeling overconfident about it's reliability. How do I address the above situations? If unit tests aren't the answer, what is? Thanks!

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  • Little CSS problem with Auto height and nested div's

    - by GeekDrop.com
    So I'm finally learning my way around CSS more and have run into a small problem. I have a container div, with a few divs inside of it, one of them is a bit if text (which can be a random height) and an image that will have a MAX height of 200px. I am using a dotted/colored background behind them that needs to auto expand to the height of whichever is the tallest, either the text or the image. Right now when i use height:auto on the container div it works perfect for the random height text: Example Screenshot But it's only adjusting according to the text's height; if the image is taller than the text, the image overflows the bottom of the background dotted/colored box. Example Screenshot The CSS I'm using currently is this: h1 div#like_detailed { margin: 0; font-size: 1.1em; width: 700px; } #details-image img { border: none; clear: left; float: right; margin: -45px 0 0 0; max-height: 200px; padding: 0 7px 0 10px; } #deets-container { background-color: #FEF; border: #190AE7 1px dotted; height: auto; margin-top: 0; margin-bottom: 30px; padding-top: 10px; padding-right: 10px; padding-left: 10px; padding-bottom: 0; } And the HTML for it is this: <div id="deets-container" class="rounded"> <!-- Button --> <div class="likebtnframe">(some code)</div> <!-- Button --> <div class="tweetbtnframe">(some code)</div> <!-- Button --> <ul id="share"> <li><a name="share">(some code)</a></li> </ul> <!-- Submitted By --> <div class="submitter_detailed"><span class="submitter-color smalltext">(some code)</span> (some code)</div> <!-- Image --> <div id="**details-image**">(some code)</div> <!-- Like / Quote --> <h1 id="**like_detailed**">(some code)</h1> </div> I have a feeling this is pretty easy but I'm running out of time to sort it out on my own. Anyone?

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  • Truth tables in code? How to structure state machine?

    - by HanClinto
    I have a (somewhat) large truth table / state machine that I need to implement in my code (embedded C). I anticipate the behavior specification of this state machine to change in the future, and so I'd like to keep this easily modifiable in the future. My truth table has 4 inputs and 4 outputs. I have it all in an Excel spreadsheet, and if I could just paste that into my code with a little formatting, that would be ideal. I was thinking I would like to access my truth table like so: u8 newState[] = decisionTable[input1][input2][input3][input4]; And then I could access the output values with: setOutputPin( LINE_0, newState[0] ); setOutputPin( LINE_1, newState[1] ); setOutputPin( LINE_2, newState[2] ); setOutputPin( LINE_3, newState[3] ); But in order to get that, it looks like I would have to do a fairly confusing table like so: static u8 decisionTable[][][][][] = {{{{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }}, {{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }}}, {{{ 0, 0, 1, 1 }, { 0, 1, 1, 1 }}, {{ 0, 1, 0, 1 }, { 1, 1, 1, 1 }}}}, {{{{ 0, 1, 0, 1 }, { 1, 1, 1, 1 }}, {{ 0, 1, 0, 1 }, { 1, 1, 1, 1 }}}, {{{ 0, 1, 1, 1 }, { 0, 1, 1, 1 }}, {{ 0, 1, 0, 1 }, { 1, 1, 1, 1 }}}}; Those nested brackets can be somewhat confusing -- does anyone have a better idea for how I can keep a pretty looking table in my code? Thanks! Edit based on HUAGHAGUAH's answer: Using an amalgamation of everyone's input (thanks -- I wish I could "accept" 3 or 4 of these answers), I think I'm going to try it as a two dimensional array. I'll index into my array using a small bit-shifting macro: #define SM_INPUTS( in0, in1, in2, in3 ) ((in0 << 0) | (in1 << 1) | (in2 << 2) | (in3 << 3)) And that will let my truth table array look like this: static u8 decisionTable[][] = { { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 1, 1 }, { 0, 1, 1, 1 }, { 0, 1, 0, 1 }, { 1, 1, 1, 1 }, { 0, 1, 0, 1 }, { 1, 1, 1, 1 }, { 0, 1, 0, 1 }, { 1, 1, 1, 1 }, { 0, 1, 1, 1 }, { 0, 1, 1, 1 }, { 0, 1, 0, 1 }, { 1, 1, 1, 1 }}; And I can then access my truth table like so: decisionTable[ SM_INPUTS( line1, line2, line3, line4 ) ] I'll give that a shot and see how it works out. I'll also be replacing the 0's and 1's with more helpful #defines that express what each state means, along with /**/ comments that explain the inputs for each line of outputs. Thanks for the help, everyone!

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  • Linux configurations that would affect Java memory usage?

    - by wmacura
    Hi, Background: I have a set of java background workers I start as part of my webapp. I develop locally on Ubuntu 10.10 and deploy to an Ubuntu 10.04LTS server (a media temple (ve) instance). They're both running the same JVM: Sun JVM 1.6.0_22-b04. As part of the initialization script each worker is started with explicit Xmx, Xms, and XX:MaxPermGen settings. Yet somehow locally all 10 workers use 250MB, while on the server they use more than 2.7GB. I don't know how to begin to track this down. I thought the Ubuntu (and thus, kernel) version might make a difference, but I tried an old 10.04 VM and it behaves as expected. I've noticed that the machine does not seem to ever use memory for buffer or cache (according to htop), which seems a bit strange, but perhaps normal for a server? (edited) Some info: (server) root@devel:/app/axir/target# uname -a Linux devel 2.6.18-028stab069.5 #1 SMP Tue May 18 17:26:16 MSD 2010 x86_64 GNU/Linux (local) wiktor@beastie:~$ uname -a Linux beastie 2.6.35-25-generic #44-Ubuntu SMP Fri Jan 21 17:40:44 UTC 2011 x86_64 GNU/Linux (edited) Comparing PS output: (ps -eo "ppid,pid,cmd,rss,sz,vsz") PPID PID CMD RSS SZ VSZ (local) 1588 1615 java -cp axir-distribution. 25484 234382 937528 1615 1631 java -cp /home/wiktor/Code/ 83472 163059 652236 1615 1657 java -cp /home/wiktor/Code/ 70624 89135 356540 1615 1658 java -cp /home/wiktor/Code/ 37652 77625 310500 1615 1669 java -cp /home/wiktor/Code/ 38096 77733 310932 1615 1675 java -cp /home/wiktor/Code/ 37420 61395 245580 1615 1684 java -cp /home/wiktor/Code/ 38000 77736 310944 1615 1703 java -cp /home/wiktor/Code/ 39180 78060 312240 1615 1712 java -cp /home/wiktor/Code/ 38488 93882 375528 1615 1719 java -cp /home/wiktor/Code/ 38312 77874 311496 1615 1726 java -cp /home/wiktor/Code/ 38656 77958 311832 1615 1727 java -cp /home/wiktor/Code/ 78016 89429 357716 (server) 22522 23560 java -cp axir-distribution. 24860 285196 1140784 23560 23585 java -cp /app/axir/target/a 100764 161629 646516 23560 23667 java -cp /app/axir/target/a 72408 92682 370728 23560 23670 java -cp /app/axir/target/a 39948 97671 390684 23560 23674 java -cp /app/axir/target/a 40140 81586 326344 23560 23739 java -cp /app/axir/target/a 39688 81542 326168 They look very similar. In fact, the question now is why, if I add up the virtual memory usage on the server (3.2GB) does it more closely reflect 2.4GB of memory used (according to free), yet locally the virtual memory used adds up to a much more substantial 4.7GB but only actually uses ~250MB. It seems that perhaps memory isn't being shared as aggressively. (if that's even possible) Thank you for your help, Wiktor

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