legacy terms - Page 214

ActiveRecord Logic Challenge - Smart Ways to Use AR Timestamp

- by keruilin

My question is somewhat specific to my app's issue, but the answer should be instructive in terms of use cases for association logic and the record timestamp. I have an NBA pick 'em game where I want to award badges for picking x number of games in a row correctly -- 10, 20, 30. Here are the models, attributes, and associations in-play: User id Pick id result # (values can be 'W', 'L', 'T', or nil. nil means hasn't resolved yet.) resolved # (values can be true, false, or nil.) game_time created_at *Note: There are cases where a pick's result field and resolved field will always be nil. Perhaps the game was cancelled. Badge id Award id user_id badge_id created_at User has many awards. User has many picks. Pick belongs to user. Badge has many awards. Award belongs to user. Award belongs to badge. One of the important rules here to capture in the code is that while a user can be awarded multiple streak badges (e.g., a user can win multiple 10-streak badges), the user CAN'T be awarded another badge for consecutive winning picks that were previously granted an award badge. One way to think of this is that all the dates of the winning picks must come after the date that the streak badge was awarded. For example, let's pretend that a user made 13 winning picks from May 5 to May 8, with the 10th winning pick occurring on May 7, and the last 3 on May 8. The user would be awarded a 10-streak badge on May 7. Now if the user makes another winning pick on May 9, the code must recognize that the user only has a streak of 4 winning picks, not 14, because the user already received an award for the first 10. Now let's assume that the user makes 6 more winning picks. In this case, the code must recognize that all winning picks since May 5 are eligible for a 20-streak badge award, and make the award. Another important rule is that when looking at a winning streak, we don't care about the game time, but rather when the pick was made (created_at). For example, let's say that Team A plays Team B on Sat. And Team C plays Team D on Sun. If the user picks Team C to beat Team D on Thurs, and Team A to beat Team C on Fri, and Team A wins on Sat, but Team C loses on Sun, then the user has a losing streak of 1. So when must the streak-check kick-in? As soon as a pick is a win. If it's a loss or tie, no point in checking. One more note: if the pick is not resolved (false) and the result is nil, that means the game was postponed and must be factored out. With all that said, what is the most efficient, effective and lean way to determine whether a user has a 10-, 20- or 30-win streak?

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Cobol: science and fiction

- by user847

There are a few threads about the relevance of the Cobol programming language on this forum, e.g. this thread links to a collection of them. What I am interested in here is a frequently repeated claim based on a study by Gartner from 1997: that there were around 200 billion lines of code in active use at that time! I would like to ask some questions to verify or falsify a couple of related points. My goal is to understand if this statement has any truth to it or if it is totally unrealistic. I apologize in advance for being a little verbose in presenting my line of thought and my own opinion on the things I am not sure about, but I think it might help to put things in context and thus highlight any wrong assumptions and conclusions I have made. Sometimes, the "200 billion lines" number is accompanied by the added claim that this corresponded to 80% of all programming code in any language in active use. Other times, the 80% merely refer to so-called "business code" (or some other vague phrase hinting that the reader is not to count mainstream software, embedded systems or anything else where Cobol is practically non-existent). In the following I assume that the code does not include double-counting of multiple installations of the same software (since that is cheating!). In particular in the time prior to the y2k problem, it has been noted that a lot of Cobol code is already 20 to 30 years old. That would mean it was written in the late 60ies and 70ies. At that time, the market leader was IBM with the IBM/370 mainframe. IBM has put up a historical announcement on his website quoting prices and availability. According to the sheet, prices are about one million dollars for machines with up to half a megabyte of memory. Question 1: How many mainframes have actually been sold? I have not found any numbers for those times; the latest numbers are for the year 2000, again by Gartner. :^( I would guess that the actual number is in the hundreds or the low thousands; if the market size was 50 billion in 2000 and the market has grown exponentially like any other technology, it might have been merely a few billions back in 1970. Since the IBM/370 was sold for twenty years, twenty times a few thousand will result in a couple of ten-thousands of machines (and that is pretty optimistic)! Question 2: How large were the programs in lines of code? I don't know how many bytes of machine code result from one line of source code on that architecture. But since the IBM/370 was a 32-bit machine, any address access must have used 4 bytes plus instruction (2, maybe 3 bytes for that?). If you count in operating system and data for the program, how many lines of code would have fit into the main memory of half a megabyte? Question 3: Was there no standard software? Did every single machine sold run a unique hand-coded system without any standard software? Seriously, even if every machine was programmed from scratch without any reuse of legacy code (wait ... didn't that violate one of the claims we started from to begin with???) we might have O(50,000 l.o.c./machine) * O(20,000 machines) = O(1,000,000,000 l.o.c.). That is still far, far, far away from 200 billion! Am I missing something obvious here? Question 4: How many programmers did we need to write 200 billion lines of code? I am really not sure about this one, but if we take an average of 10 l.o.c. per day, we would need 55 million man-years to achieve this! In the time-frame of 20 to 30 years this would mean that there must have existed two to three million programmers constantly writing, testing, debugging and documenting code. That would be about as many programmers as we have in China today, wouldn't it? Question 5: What about the competition? So far, I have come up with two things here: 1) IBM had their own programming language, PL/I. Above I have assumed that the majority of code has been written exclusively using Cobol. However, all other things being equal I wonder if IBM marketing had really pushed their own development off the market in favor of Cobol on their machines. Was there really no relevant code base of PL/I? 2) Sometimes (also on this board in the thread quoted above) I come across the claim that the "200 billion lines of code" are simply invisible to anybody outside of "governments, banks ..." (and whatnot). Actually, the DoD had funded their own language in order to increase cost effectiveness and reduce the proliferation of programming language. This lead to their use of Ada. Would they really worry about having so many different programming languages if they had predominantly used Cobol? If there was any language running on "government and military" systems outside the perception of mainstream computing, wouldn't that language be Ada? I hope someone can point out any flaws in my assumptions and/or conclusions and shed some light on whether the above claim has any truth to it or not.

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Web browsing is fast, but downloads are slow

- by Ricket

I work for a company on my university's campus, helping with general IT problems and some web development. But lately there has been a problem that has me and my boss completely stumped. We, plus one contractor, make up the entire IT department, so I'm reaching out to you for help. All around the office, we have wall jacks. These collect in a closet down the hall and all plug into a switch. This switch, along with our individual server jacks, plugs into another switch, and that switch plugs into our firewall hardware. Then the firewall is connected out to our campus network. Our campus internet is, well, very fast. I don't know exactly the terms, tiers, etc., but we have thousands of students and downloads can run as fast as 10 MB/s at night; uploads are sometimes even faster. I think we're practically ISP level. In short, I have a lot of faith that it is not the campus side of things that is causing a problem, combined with other evidence I'll mention in a moment. So our symptoms: web browsing is fast. Web pages, images, etc. load instantly. No problems there. But then when I go to download something, the download starts fast but very quickly (a matter of seconds) drops to nearly 0. Often it will actually drop to 0 and time out. This happens with even very small files, 1 MB or less. It smells to me like a QoS sort of thing. I'm not entirely sure, and I wanted to get your opinions first. My boss is hesitant to touch our firewall, much less let me touch it, and it was set up and is managed by a consultant remotely. These problems don't seem tied to a time of the day. I've tried downloads after 5:00 and still the same thing happens. From my desk, I can turn on my wireless adapter and pick up the campus wireless access point. If I unplug ethernet and connect to it, downloads are fast. This adds to my suspicion that it's limited to our company network. Also, a number of weeks ago the consultant upgraded our firewall firmware. Suddenly everything was very fast. I tested with downloads from Sun and speedtest.net and things were blazing fast, as they should be with our campus internet! It was wonderful, and I figured the slow speeds were an old firmware bug. In a matter of days, things steadily declined until they were back to the old symptoms. Oh, and we have antivirus installed on every computer, and we keep it up to date. Though I suppose the possibility is still there that someone could have spyware which is bogging down our internet, in which case what is the easiest/best way to find this out? (maybe this should go in a separate question) Thank you for your patience in reading all of this. Do you have any ideas as to what I can try? Is this something that you've experienced before? What sort of tools or methods can I use to try and diagnose the problem? P.S. everything here is Windows. Windows Server 2003 and 2008 on our servers, and Windows XP on employees' machines. Update: We are submitting a ticket to the university to just take a look and see if they see anything unusual and/or can suggestion methods for us to try and pinpoint our problem. Hopefully they'll be helpful! I'll update this to let you know what goes on. Update again: We found a hub (yes, a HUB) right between our campus connection and our firewall. It had only those two ethernet cables plugged into it, nothing else. After removing the hub, our speeds have jumped up to several mbps. However in talking with the campus, we got them to run a gigabit line to our firewall in place of the 100mbps line. As of friday, we are at about 65 mbps up and down (according to speedtest.net at 8am)!! Go NC State!!

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WPF BackgroundWorker Execution

- by Sanju

Hi All, I've been programming C# for a while now (I'm a Computer Science major), and have never had to implement threading. I am currently building an application for a client that requires threading for a series of operations. Due to the nature of the client/provider agreement, I cannot release the source I am working with. The code that I have posted is in a general form. Pretty much the basic idea of what I am implementing, excluding the content specific source. The first Snippet demonstrates my basic structure, The Progress class is a custom progress window that is displayed as a dialog to prevent user UI interaction. I am currently using the code to complete database calls based on a collection of objects in another area of the application code. For example, I have a collection of "Objects" of one of my custom classes, that I perform these database calls on or on behalf of. My current set up works just fine when I call the "GeneralizedFunction" one and only one time. What I need to do is call this function once for every object in the collection. I was attempting to use a foreach loop to iterate through the collection, then I tried a for loop. For both loops, the result was the same. The Async operation performs exactly as desired for the first item in the collection. This, however, is the only one it works for. For each subsequent item, the progress box (my custom window) displays and immediately closes. In terms of the database calls, the calls for the first item in the collection are the only ones that successfully complete. All others aren't attempted. I've tried everything that I know and don't know to do, but I just cannot seem to get it to work. How can I get this to work for my entire collection? Any and all help is very greatly appreciated. Progress progress; BackgroundWorker worker; // Cancel the current process private void CancelProcess(object sender, EventArgs e) { worker.CancelAsync(); } // The main process ... "Generalized" private void GeneralizedFunction() { progress = new Progress(); progress.Cancel += CancelProcess; progress.Owner = this; Dispatcher pDispatcher = progress.Dispatcher; worker = new BackgroundWorker(); worker.WorkerSupportsCancellation = true; object[] workArgs = { arg1, arg2, arg3}; worker.DoWork += delegate(object s, DoWorkEventArgs args) { /* All main logic here */ foreach(Class ClassObject in ClassObjectCollection) { //Some more logic here UpdateProgressDelegate update = new UpdateProgressDelegate(updateProgress); pDispatcher.BeginInvoke(update, arg1,arg2,arg3); Thread.Sleep(1000); } }; worker.RunWorkerCompleted += delegate(object s, RunWorkerCompletedEventArgs args) { progress.Close(); }; worker.RunWorkerAsync(workArgs); progress.ShowDialog(); } public delegate void UpdateProgressDelegate(arg1,arg2,arg3); private void updateProgress(arg1,arg2,arg3) { //Update progress }

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Mysql optimization question - How to apply AND logic in search and limit on results in one query?

- by sandeepan-nath

This is a little long but I have provided all the database structures and queries so that you can run it immediately and help me. Run the following queries:- CREATE TABLE IF NOT EXISTS `Tutor_Details` ( `id_tutor` int(10) NOT NULL auto_increment, `firstname` varchar(100) NOT NULL default '', `surname` varchar(155) NOT NULL default '', PRIMARY KEY (`id_tutor`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=41 ; INSERT INTO `Tutor_Details` (`id_tutor`,`firstname`, `surname`) VALUES (1, 'Sandeepan', 'Nath'), (2, 'Bob', 'Cratchit'); CREATE TABLE IF NOT EXISTS `Classes` ( `id_class` int(10) unsigned NOT NULL auto_increment, `id_tutor` int(10) unsigned NOT NULL default '0', `class_name` varchar(255) default NULL, PRIMARY KEY (`id_class`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=229 ; INSERT INTO `Classes` (`id_class`,`class_name`, `id_tutor`) VALUES (1, 'My Class', 1), (2, 'Sandeepan Class', 2); CREATE TABLE IF NOT EXISTS `Tags` ( `id_tag` int(10) unsigned NOT NULL auto_increment, `tag` varchar(255) default NULL, PRIMARY KEY (`id_tag`), UNIQUE KEY `tag` (`tag`), KEY `id_tag` (`id_tag`), KEY `tag_2` (`tag`), KEY `tag_3` (`tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=18 ; INSERT INTO `Tags` (`id_tag`, `tag`) VALUES (1, 'Bob'), (6, 'Class'), (2, 'Cratchit'), (4, 'Nath'), (3, 'Sandeepan'), (5, 'My'); CREATE TABLE IF NOT EXISTS `Tutors_Tag_Relations` ( `id_tag` int(10) unsigned NOT NULL default '0', `id_tutor` int(10) default NULL, KEY `Tutors_Tag_Relations` (`id_tag`), KEY `id_tutor` (`id_tutor`), KEY `id_tag` (`id_tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `Tutors_Tag_Relations` (`id_tag`, `id_tutor`) VALUES (3, 1), (4, 1), (1, 2), (2, 2); CREATE TABLE IF NOT EXISTS `Class_Tag_Relations` ( `id_tag` int(10) unsigned NOT NULL default '0', `id_class` int(10) default NULL, `id_tutor` int(10) NOT NULL, KEY `Class_Tag_Relations` (`id_tag`), KEY `id_class` (`id_class`), KEY `id_tag` (`id_tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `Class_Tag_Relations` (`id_tag`, `id_class`, `id_tutor`) VALUES (5, 1, 1), (6, 1, 1), (3, 2, 2), (6, 2, 2); Following is about the tables:- There are tutors who create classes. Tutor_Details - Stores tutors Classes - Stores classes created by tutors And for searching we are using a tags based approach. All the keywords are stored in tags table (while classes/tutors are created) and tag relations are entered in Tutor_Tag_Relations and Class_Tag_Relations tables (for tutors and classes respectively)like this:- Tags - id_tag tag (this is a a unique field) Tutors_Tag_Relations - Stores tag relations while the tutors are created. Class_Tag_Relations - Stores tag relations while any tutor creates a class In the present data in database, tutor "Sandeepan Nath" has has created class "My Class" and "Bob Cratchit" has created "Sandeepan Class". 3.Requirement The requirement is to return tutor records from Tutor_Details table such that all the search terms (AND logic) are present in the union of these two sets - 1. Tutor_Details table 2. classes created by a tutor in Classes table) Example search and expected results:- Search Term Result "Sandeepan Class" Tutor Sandeepan Nath's record from Tutor Details table "Class" Both the tutors from ... Most importantly, there should be only one mysql query and a LIMIT applicable on the number of results. Following is a working query which I have so far written (It just applies OR logic of search key words instead of the desired AND logic). SELECT td . * FROM Tutor_Details AS td LEFT JOIN Tutors_Tag_Relations AS ttagrels ON td.id_tutor = ttagrels.id_tutor LEFT JOIN Classes AS wc ON td.id_tutor = wc.id_tutor INNER JOIN Class_Tag_Relations AS wtagrels ON td.id_tutor = wtagrels.id_tutor LEFT JOIN Tags AS t ON t.id_tag = ttagrels.id_tag OR t.id_tag = wtagrels.id_tag WHERE t.tag LIKE '%Sandeepan%' OR t.tag LIKE '%Nath%' GROUP BY td.id_tutor LIMIT 20 Please help me with anything you can. Thanks

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XML over HTTP with JMS and Spring

- by Will Sumekar

I have a legacy HTTP server where I need to send an XML file over HTTP request (POST) using Java (not browser) and the server will respond with another XML in its HTTP response. It is similar to Web Service but there's no WSDL and I have to follow the existing XML structure to construct my XML to be sent. I have done a research and found an example that matches my requirement here. The example uses HttpClient from Apache Commons. (There are also other examples I found but they use java.net networking package (like URLConnection) which is tedious so I don't want to use them). But it's also my requirement to use Spring and JMS. I know from Spring's reference that it's possible to combine HttpClient, JMS and Spring. My question is, how? Note that it's NOT in my requirement to use HttpClient. If you have a better suggestion, I'm welcome. Appreciate it. For your reference, here's the XML-over-HTTP example I've been talking about: /* * $Header: * $Revision$ * $Date$ * ==================================================================== * * Copyright 2002-2004 The Apache Software Foundation * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * * [Additional notices, if required by prior licensing conditions] * */ import java.io.File; import java.io.FileInputStream; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.methods.InputStreamRequestEntity; import org.apache.commons.httpclient.methods.PostMethod; /** * * This is a sample application that demonstrates * how to use the Jakarta HttpClient API. * * This application sends an XML document * to a remote web server using HTTP POST * * @author Sean C. Sullivan * @author Ortwin Glück * @author Oleg Kalnichevski */ public class PostXML { /** * * Usage: * java PostXML http://mywebserver:80/ c:\foo.xml * * @param args command line arguments * Argument 0 is a URL to a web server * Argument 1 is a local filename * */ public static void main(String[] args) throws Exception { if (args.length != 2) { System.out.println( "Usage: java -classpath <classpath> [-Dorg.apache.commons."+ "logging.simplelog.defaultlog=<loglevel>]" + " PostXML <url> <filename>]"); System.out.println("<classpath> - must contain the "+ "commons-httpclient.jar and commons-logging.jar"); System.out.println("<loglevel> - one of error, "+ "warn, info, debug, trace"); System.out.println("<url> - the URL to post the file to"); System.out.println("<filename> - file to post to the URL"); System.out.println(); System.exit(1); } // Get target URL String strURL = args[0]; // Get file to be posted String strXMLFilename = args[1]; File input = new File(strXMLFilename); // Prepare HTTP post PostMethod post = new PostMethod(strURL); // Request content will be retrieved directly // from the input stream // Per default, the request content needs to be buffered // in order to determine its length. // Request body buffering can be avoided when // content length is explicitly specified post.setRequestEntity(new InputStreamRequestEntity( new FileInputStream(input), input.length())); // Specify content type and encoding // If content encoding is not explicitly specified // ISO-8859-1 is assumed post.setRequestHeader( "Content-type", "text/xml; charset=ISO-8859-1"); // Get HTTP client HttpClient httpclient = new HttpClient(); // Execute request try { int result = httpclient.executeMethod(post); // Display status code System.out.println("Response status code: " + result); // Display response System.out.println("Response body: "); System.out.println(post.getResponseBodyAsString()); } finally { // Release current connection to the connection pool // once you are done post.releaseConnection(); } } }

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inserting new relationship data in core-data

- by michael

My app will allow users to create a personalised list of events from a large list of events. I have a table view which simply displays these events, tapping on one of them takes the user to the event details view, which has a button "add to my events". In this detailed view I own the original event object, retrieved via an NSFetchedResultsController and passed to the detailed view (via a table cell, the same as the core data recipes sample). I have no trouble retrieving/displaying information from this "event". I am then trying to add it to the list of MyEvents represented by a one to many (inverse) relationship: This code: NSManagedObjectContext *context = [event managedObjectContext]; MyEvents *myEvents = (MyEvents *)[NSEntityDescription insertNewObjectForEntityForName:@"MyEvents" inManagedObjectContext:context]; [myEvents addEventObject:event];//ERROR And this code (suggested below): //would this add to or overwrite the "list" i am attempting to maintain NSManagedObjectContext *context = [event managedObjectContext]; MyEvents *myEvents = (MyEvents *)[NSEntityDescription insertNewObjectForEntityForName:@"MyEvents" inManagedObjectContext:context]; NSMutableSet *myEvent = [myEvents mutableSetValueForKey:@"event"]; [myEvent addObject:event]; //ERROR Bot produce (at the line indicated by //ERROR): *** -[NSComparisonPredicate evaluateWithObject:]: message sent to deallocated instance Seems I may have missed something fundamental. I cant glean any more information through the use of debugging tools, with my knowledge of them. 1) Is this a valid way to compile and store an editable list like this? 2) Is there a better way? 3) What could possibly be the deallocated instance in error? -- I have now modified the Event entity to have a to-many relationship called "myEvents" which referrers to itself. I can add Events to this fine, and logging the object shows the correct memory addresses appearing for the relationship after a [event addMyEventObject:event];. The same failure happens right after this however. I am still at a loss to understand what is going wrong. This is the backtrace #0 0x01f753a7 in ___forwarding___ () #1 0x01f516c2 in __forwarding_prep_0___ () #2 0x01c5aa8f in -[NSFetchedResultsController(PrivateMethods) _preprocessUpdatedObjects:insertsInfo:deletesInfo:updatesInfo:sectionsWithDeletes:newSectionNames:treatAsRefreshes:] () #3 0x01c5d63b in -[NSFetchedResultsController(PrivateMethods) _managedObjectContextDidChange:] () #4 0x0002e63a in _nsnote_callback () #5 0x01f40005 in _CFXNotificationPostNotification () #6 0x0002bef0 in -[NSNotificationCenter postNotificationName:object:userInfo:] () #7 0x01bbe17d in -[NSManagedObjectContext(_NSInternalNotificationHandling) _postObjectsDidChangeNotificationWithUserInfo:] () #8 0x01c1d763 in -[NSManagedObjectContext(_NSInternalChangeProcessing) _createAndPostChangeNotification:withDeletions:withUpdates:withRefreshes:] () #9 0x01ba25ea in -[NSManagedObjectContext(_NSInternalChangeProcessing) _processRecentChanges:] () #10 0x01bdfb3a in -[NSManagedObjectContext processPendingChanges] () #11 0x01bd0957 in _performRunLoopAction () #12 0x01f4d252 in __CFRunLoopDoObservers () #13 0x01f4c65f in CFRunLoopRunSpecific () #14 0x01f4bc48 in CFRunLoopRunInMode () #15 0x0273878d in GSEventRunModal () #16 0x02738852 in GSEventRun () #17 0x002ba003 in UIApplicationMain () solution I managed to get to the bottom of this. I was fetching the event in question using a NSFetchedResultsController with a NSPredicate which I was releasing after I had the results. Retrieving values from the entities returned was no problem, but when I tried to update any of them it gave the error above. It should not have been released. oustanding part of my question What is a good way to create this sub list from a list of existing items in terms of a core data model. I don't believe its any of the ways I tried here. I need to show/edit it in another table view. Perhaps there is a better way than a boolean property on each event entity? The relationship idea above doesn't seem to work here (even though I can now create it). Cheers.

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Why is processing a sorted array faster than an unsorted array?

- by GManNickG

Here is a piece of code that shows some very peculiar performance. For some strange reason, sorting the data miraculously speeds up the code by almost 6x: #include <algorithm> #include <ctime> #include <iostream> int main() { // generate data const unsigned arraySize = 32768; int data[arraySize]; for (unsigned c = 0; c < arraySize; ++c) data[c] = std::rand() % 256; // !!! with this, the next loop runs faster std::sort(data, data + arraySize); // test clock_t start = clock(); long long sum = 0; for (unsigned i = 0; i < 100000; ++i) { // primary loop for (unsigned c = 0; c < arraySize; ++c) { if (data[c] >= 128) sum += data[c]; } } double elapsedTime = static_cast<double>(clock() - start) / CLOCKS_PER_SEC; std::cout << elapsedTime << std::endl; std::cout << "sum = " << sum << std::endl; } Without std::sort(data, data + arraySize);, the code runs in 11.54 seconds. With the sorted data, the code runs in 1.93 seconds. Initially I thought this might be just a language or compiler anomaly. So I tried it Java... import java.util.Arrays; import java.util.Random; public class Main { public static void main(String[] args) { // generate data int arraySize = 32768; int data[] = new int[arraySize]; Random rnd = new Random(0); for (int c = 0; c < arraySize; ++c) data[c] = rnd.nextInt() % 256; // !!! with this, the next loop runs faster Arrays.sort(data); // test long start = System.nanoTime(); long sum = 0; for (int i = 0; i < 100000; ++i) { // primary loop for (int c = 0; c < arraySize; ++c) { if (data[c] >= 128) sum += data[c]; } } System.out.println((System.nanoTime() - start) / 1000000000.0); System.out.println("sum = " + sum); } } with a similar but less extreme result. My first thought was that sorting brings the data into cache, but my next thought was how silly that is because the array was just generated. What is going on? Why is a sorted array faster than an unsorted array? The code is summing up some independent terms, the order should not matter.

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Where should I create my DbCommand instances?

- by Domenic

I seemingly have two choices: Make my class implement IDisposable. Create my DbCommand instances as private readonly fields, and in the constructor, add the parameters that they use. Whenever I want to write to the database, bind to these parameters (reusing the same command instances), set the Connection and Transaction properties, then call ExecuteNonQuery. In the Dispose method, call Dispose on each of these fields. Each time I want to write to the database, write using(var cmd = new DbCommand("...", connection, transaction)) around the usage of the command, and add parameters and bind to them every time as well, before calling ExecuteNonQuery. I assume I don't need a new command for each query, just a new command for each time I open the database (right?). Both of these seem somewhat inelegant and possibly incorrect. For #1, it is annoying for my users that I this class is now IDisposable just because I have used a few DbCommands (which should be an implementation detail that they don't care about). I also am somewhat suspicious that keeping a DbCommand instance around might inadvertently lock the database or something? For #2, it feels like I'm doing a lot of work (in terms of .NET objects) each time I want to write to the database, especially with the parameter-adding. It seems like I create the same object every time, which just feels like bad practice. For reference, here is my current code, using #1: using System; using System.Net; using System.Data.SQLite; public class Class1 : IDisposable { private readonly SQLiteCommand updateCookie = new SQLiteCommand("UPDATE moz_cookies SET value = @value, expiry = @expiry, isSecure = @isSecure, isHttpOnly = @isHttpOnly WHERE name = @name AND host = @host AND path = @path"); public Class1() { this.updateCookie.Parameters.AddRange(new[] { new SQLiteParameter("@name"), new SQLiteParameter("@value"), new SQLiteParameter("@host"), new SQLiteParameter("@path"), new SQLiteParameter("@expiry"), new SQLiteParameter("@isSecure"), new SQLiteParameter("@isHttpOnly") }); } private static void BindDbCommandToMozillaCookie(DbCommand command, Cookie cookie) { long expiresSeconds = (long)cookie.Expires.TotalSeconds; command.Parameters["@name"].Value = cookie.Name; command.Parameters["@value"].Value = cookie.Value; command.Parameters["@host"].Value = cookie.Domain; command.Parameters["@path"].Value = cookie.Path; command.Parameters["@expiry"].Value = expiresSeconds; command.Parameters["@isSecure"].Value = cookie.Secure; command.Parameters["@isHttpOnly"].Value = cookie.HttpOnly; } public void WriteCurrentCookiesToMozillaBasedBrowserSqlite(string databaseFilename) { using (SQLiteConnection connection = new SQLiteConnection("Data Source=" + databaseFilename)) { connection.Open(); using (SQLiteTransaction transaction = connection.BeginTransaction()) { this.updateCookie.Connection = connection; this.updateCookie.Transaction = transaction; foreach (Cookie cookie in SomeOtherClass.GetCookieArray()) { Class1.BindDbCommandToMozillaCookie(this.updateCookie, cookie); this.updateCookie.ExecuteNonQuery(); } transaction.Commit(); } } } #region IDisposable implementation protected virtual void Dispose(bool disposing) { if (!this.disposed && disposing) { this.updateCookie.Dispose(); } this.disposed = true; } public void Dispose() { this.Dispose(true); GC.SuppressFinalize(this); } ~Class1() { this.Dispose(false); } private bool disposed; #endregion }

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C++0x rvalue references - lvalues-rvalue binding

- by Doug

This is a follow-on question to http://stackoverflow.com/questions/2748866/c0x-rvalue-references-and-temporaries In the previous question, I asked how this code should work: void f(const std::string &); //less efficient void f(std::string &&); //more efficient void g(const char * arg) { f(arg); } It seems that the move overload should probably be called because of the implicit temporary, and this happens in GCC but not MSVC (or the EDG front-end used in MSVC's Intellisense). What about this code? void f(std::string &&); //NB: No const string & overload supplied void g1(const char * arg) { f(arg); } void g2(const std::string & arg) { f(arg); } It seems that, based on the answers to my previous question that function g1 is legal (and is accepted by GCC 4.3-4.5, but not by MSVC). However, GCC and MSVC both reject g2 because of clause 13.3.3.1.4/3, which prohibits lvalues from binding to rvalue ref arguments. I understand the rationale behind this - it is explained in N2831 "Fixing a safety problem with rvalue references". I also think that GCC is probably implementing this clause as intended by the authors of that paper, because the original patch to GCC was written by one of the authors (Doug Gregor). However, I don't this is quite intuitive. To me, (a) a const string & is conceptually closer to a string && than a const char *, and (b) the compiler could create a temporary string in g2, as if it were written like this: void g2(const std::string & arg) { f(std::string(arg)); } Indeed, sometimes the copy constructor is considered to be an implicit conversion operator. Syntactically, this is suggested by the form of a copy constructor, and the standard even mentions this specifically in clause 13.3.3.1.2/4, where the copy constructor for derived-base conversions is given a higher conversion rank than other implicit conversions: A conversion of an expression of class type to the same class type is given Exact Match rank, and a conversion of an expression of class type to a base class of that type is given Conversion rank, in spite of the fact that a copy/move constructor (i.e., a user-defined conversion function) is called for those cases. (I assume this is used when passing a derived class to a function like void h(Base), which takes a base class by value.) Motivation My motivation for asking this is something like the question asked in http://stackoverflow.com/questions/2696156/how-to-reduce-redundant-code-when-adding-new-c0x-rvalue-reference-operator-over ("How to reduce redundant code when adding new c++0x rvalue reference operator overloads"). If you have a function that accepts a number of potentially-moveable arguments, and would move them if it can (e.g. a factory function/constructor: Object create_object(string, vector<string>, string) or the like), and want to move or copy each argument as appropriate, you quickly start writing a lot of code. If the argument types are movable, then one could just write one version that accepts the arguments by value, as above. But if the arguments are (legacy) non-movable-but-swappable classes a la C++03, and you can't change them, then writing rvalue reference overloads is more efficient. So if lvalues did bind to rvalues via an implicit copy, then you could write just one overload like create_object(legacy_string &&, legacy_vector<legacy_string> &&, legacy_string &&) and it would more or less work like providing all the combinations of rvalue/lvalue reference overloads - actual arguments that were lvalues would get copied and then bound to the arguments, actual arguments that were rvalues would get directly bound. Questions My questions are then: Is this a valid interpretation of the standard? It seems that it's not the conventional or intended one, at any rate. Does it make intuitive sense? Is there a problem with this idea that I"m not seeing? It seems like you could get copies being quietly created when that's not exactly expected, but that's the status quo in places in C++03 anyway. Also, it would make some overloads viable when they're currently not, but I don't see it being a problem in practice. Is this a significant enough improvement that it would be worth making e.g. an experimental patch for GCC?

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Foolishness Check: PHP Class finds Class file but not Class in the file.

- by Daniel Bingham

I'm at a loss here. I've defined an abstract superclass in one file and a subclass in another. I have required the super-classes file and the stack trace reports to find an include it. However, it then returns an error when it hits the 'extends' line: Fatal error: Class 'HTMLBuilder' not found in View/Markup/HTML/HTML4.01/HTML4_01Builder.php on line 7. I had this working with another class tree that uses factories a moment ago. I just added the builder layer in between the factories and the consumer. The factory layer looked almost exactly the same in terms of includes and dependencies. So that makes me think I must have done something silly that's causes the HTMLBuilder.php file to not be included correctly or interpreted correctly or some such. Here's the full stack trace (paths slightly altered): # Time Memory Function Location 1 0.0001 53904 {main}( ) ../index.php:0 2 0.0002 67600 require_once( 'View/Page.php' ) ../index.php:3 3 0.0003 75444 require_once( 'View/Sections/SectionFactory.php' ) ../Page.php:4 4 0.0003 81152 require_once( 'View/Sections/HTML/HTMLSectionFactory.php' ) ../SectionFactory.php:3 5 0.0004 92108 require_once( 'View/Sections/HTML/HTMLTitlebarSection.php' ) ../HTMLSectionFactory.php:5 6 0.0005 99716 require_once( 'View/Markup/HTML/HTMLBuilder.php' ) ../HTMLTitlebarSection.php:3 7 0.0005 103580 require_once( 'View/Markup/MarkupBuilder.php' ) ../HTMLBuilder.php:3 8 0.0006 124120 require_once( 'View/Markup/HTML/HTML4.01/HTML4_01Builder.php' ) ../MarkupBuilder.php:3 Here's the code in question: Parent class (View/Markup/HTML/HTMLBuilder.php): <?php require_once('View/Markup/MarkupBuilder.php'); abstract class HTMLBuilder extends MarkupBuilder { public abstract function getLink($text, $href); public abstract function getImage($src, $alt); public abstract function getDivision($id, array $classes=NULL, array $children=NULL); public abstract function getParagraph($text, array $classes=NULL, $id=NULL); } ?> Child Class, (View/Markup/HTML/HTML4.01/HTML4_01Builder.php): <?php require_once('HTML4_01Factory.php'); require_once('View/Markup/HTML/HTMLBuilder.php'); class HTML4_01Builder extends HTMLBuilder { private $factory; public function __construct() { $this->factory = new HTML4_01Factory(); } public function getLink($href, $text) { $link = $this->factory->getA(); $link->addAttribute('href', $href); $link->addChild($this->factory->getText($text)); return $link; } public function getImage($src, $alt) { $image = $this->factory->getImg(); $image->addAttribute('src', $src); $image->addAttribute('alt', $alt); return $image; } public function getDivision($id, array $classes=NULL, array $children=NULL) { $div = $this->factory->getDiv(); $div->setID($id); if(!empty($classes)) { $div->addClasses($classes); } if(!empty($children)) { $div->addChildren($children); } return $div; } public function getParagraph($text, array $classes=NULL, $id=NULL) { $p = $this->factory->getP(); $p->addChild($this->factory->getText($text)); if(!empty($classes)) { $p->addClasses($classes); } if(!empty($id)) { $p->setID($id); } return $p; } } ?> I would appreciate any and all ideas. I'm at a complete loss here as to what is going wrong. I'm sure it's something stupid I just can't see...

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algorithm q: Fuzzy matching of structured data

- by user86432

I have a fairly small corpus of structured records sitting in a database. Given a tiny fraction of the information contained in a single record, submitted via a web form (so structured in the same way as the table schema), (let us call it the test record) I need to quickly draw up a list of the records that are the most likely matches for the test record, as well as provide a confidence estimate of how closely the search terms match a record. The primary purpose of this search is to discover whether someone is attempting to input a record that is duplicate to one in the corpus. There is a reasonable chance that the test record will be a dupe, and a reasonable chance the test record will not be a dupe. The records are about 12000 bytes wide and the total count of records is about 150,000. There are 110 columns in the table schema and 95% of searches will be on the top 5% most commonly searched columns. The data is stuff like names, addresses, telephone numbers, and other industry specific numbers. In both the corpus and the test record it is entered by hand and is semistructured within an individual field. You might at first blush say "weight the columns by hand and match word tokens within them", but it's not so easy. I thought so too: if I get a telephone number I thought that would indicate a perfect match. The problem is that there isn't a single field in the form whose token frequency does not vary by orders of magnitude. A telephone number might appear 100 times in the corpus or 1 time in the corpus. The same goes for any other field. This makes weighting at the field level impractical. I need a more fine-grained approach to get decent matching. My initial plan was to create a hash of hashes, top level being the fieldname. Then I would select all of the information from the corpus for a given field, attempt to clean up the data contained in it, and tokenize the sanitized data, hashing the tokens at the second level, with the tokens as keys and frequency as value. I would use the frequency count as a weight: the higher the frequency of a token in the reference corpus, the less weight I attach to that token if it is found in the test record. My first question is for the statisticians in the room: how would I use the frequency as a weight? Is there a precise mathematical relationship between n, the number of records, f(t), the frequency with which a token t appeared in the corpus, the probability o that a record is an original and not a duplicate, and the probability p that the test record is really a record x given the test and x contain the same t in the same field? How about the relationship for multiple token matches across multiple fields? Since I sincerely doubt that there is, is there anything that gets me close but is better than a completely arbitrary hack full of magic factors? Barring that, has anyone got a way to do this? I'm especially keen on other suggestions that do not involve maintaining another table in the database, such as a token frequency lookup table :). This is my first post on StackOverflow, thanks in advance for any replies you may see fit to give.

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Create / build / generate a web form that can be on my server and has modern looks and could be impl

- by Luay

I have a small web site and would like to add a 'contact us' form and a 'feedback' form. i would like the forms to satisfy the following: 1- be modern looking (with beautiful css effects) 2- the form fields are validated properly and 'inline'. What I mean is once a user skips a required field or enters an email address incorrectly some kind of tooltip or icon is displayed to ask him to cerrect the error (as opposed to a message box that appears after the user clicks 'submit') 3- once the submit button is clicked the form contents are emailed to me. 4- the whole thing can be setup by a noob like myself. 5- no ads on the form I have been searching for at least 5 days for a solution but I can't seem to find anything the would satisfy the above 5 conditions. I don't mind paying for a solution as long as it is hosted on my site and it is a one off payment and not a monthly payment. So far my search has lead me to the following: 1 wufoo. The good: the generated forms seem to look okay but not the best there is. The bad: the free service is limited to 100 submissions. ads on the form. it is not hosted on my server. Paid service requires monthly payments 2- emailmeform: almost same as above except the generated form looks old. They do have an offer where you pay only $4 to get the form and set it up on your own site but that doesn't solve the fact that the forms look old. 3- formAssembly: same as above with minor variations (the generated form looks better) 4- formchamp, formthis, kontaktr,... And other similar online services: the same problem. either the form generated looks outdated or require monthly payments or they put ads...they don't satisfy my conditions. 5- coffeecup form builder. a desktop software. The problem is the generated forms look too old and use flash. 6- simfatic. Another software. Much better than coffeecup. almost satisfies my conditions but the forms not as good as I like. 7- many, many php scripts or html templates that look so outdated or fail when tested (probably because they are too old). Seriously guys, how hard is this. At least 90%+ of website contain at least a 'contact us' form. Why aren't there better solutions? if there is I can't seem to find them. In terms of looks I want something similar to this: http://web-kreation.com/articles/lightform-free-ajaxphp-contact-form/ It is called lightform. And this is a perfect example of what I mean by 'inline' validation. the only problem: there is no script to handle sending the mail. Even if I find one, I don't know how to modify it for my needs. So could you please help me out. I really can't search anymore. I reached rock bottom with this issue. I need a complete solution. If nothing exists then at least a: 1- form template (html) that looks nice and can easily be modified 2- a validation script that does 'inline' validation like the example above (or similar to it) and can be easily implemented by a noob like me to work with the html form. 3- a php script that will handle sending the email and can be easily implemented (all three working in harmony). I hope there is a complete solution but am I asking for too much? Pretty please...help...

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Replace conditional with polymorphism refactoring or similar?

- by Anders Svensson

Hi, I have tried to ask a variant of this question before. I got some helpful answers, but still nothing that felt quite right to me. It seems to me this shouldn't really be that hard a nut to crack, but I'm not able to find an elegant simple solution. (Here's my previous post, but please try to look at the problem stated here as procedural code first so as not to be influenced by the earlier explanation which seemed to lead to very complicated solutions: http://stackoverflow.com/questions/2772858/design-pattern-for-cost-calculator-app ) Basically, the problem is to create a calculator for hours needed for projects that can contain a number of services. In this case "writing" and "analysis". The hours are calculated differently for the different services: writing is calculated by multiplying a "per product" hour rate with the number of products, and the more products are included in the project, the lower the hour rate is, but the total number of hours is accumulated progressively (i.e. for a medium-sized project you take both the small range pricing and then add the medium range pricing up to the number of actual products). Whereas for analysis it's much simpler, it is just a bulk rate for each size range. How would you be able to refactor this into an elegant and preferably simple object-oriented version (please note that I would never write it like this in a purely procedural manner, this is just to show the problem in another way succinctly). I have been thinking in terms of factory, strategy and decorator patterns, but can't get any to work well. (I read Head First Design Patterns a while back, and both the decorator and factory patterns described have some similarities to this problem, but I have trouble seeing them as good solutions as stated there. The decorator example seems very complicated for just adding condiments, but maybe it could work better here, I don't know. And the factory pattern example with the pizza factory...well it just seems to create such a ridiculous explosion of classes, at least in their example. I have found good use for factory patterns before, but I can't see how I could use it here without getting a really complicated set of classes) The main goal would be to only have to change in one place (loose coupling etc) if I were to add a new parameter (say another size, like XSMALL, and/or another service, like "Administration"). Here's the procedural code example: public class Conditional { private int _numberOfManuals; private string _serviceType; private const int SMALL = 2; private const int MEDIUM = 8; public int GetHours() { if (_numberOfManuals <= SMALL) { if (_serviceType == "writing") return 30 * _numberOfManuals; if (_serviceType == "analysis") return 10; } else if (_numberOfManuals <= MEDIUM) { if (_serviceType == "writing") return (SMALL * 30) + (20 * _numberOfManuals - SMALL); if (_serviceType == "analysis") return 20; } else //i.e. LARGE { if (_serviceType == "writing") return (SMALL * 30) + (20 * (MEDIUM - SMALL)) + (10 * _numberOfManuals - MEDIUM); if (_serviceType == "analysis") return 30; } return 0; //Just a default fallback for this contrived example } } All replies are appreciated! I hope someone has a really elegant solution to this problem that I actually thought from the beginning would be really simple... Regards, Anders

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Database Table Schema and Aggregate Roots

- by bretddog

Hi, Applicaiton is single user, 1-tier(1 pc), database SqlCE. DataService layer will be (I think) : Repository returning domain objects and quering database with LinqToSql (dbml). There are obviously a lot more columns, this is simplified view. http://img573.imageshack.us/img573/3612/ss20110115171817w.png This is my first attempt of creating a 2 tables database. I think the table schema makes sense, but I need some reassurance or critics. Because the table relations looks quite scary to be honest. I'm hoping you could; Look at the table schema and respond if there are clear signs of troubles or errors that you spot right away.. And if you have time, Look at Program Summary/Questions, and see if the table layout makes makes sense to those points. Please be brutal, I will try to defend :) Program summary: a) A set of categories, each having a set of strategies (1:m) b) Each day a number of items will be produced. And each strategy MAY reference it. (So there can be 50 items, and a strategy may reference 23 of them) c) An item can be referenced by more than one strategy. So I think it's an m:m relation. d) Status values will be logged at fixed time-fractions through the day, for: - .... each Strategy.....each StrategyItem....each item e) An action on an item may be executed by a strategy that reference it. - This is logged as ItemAction (Could have called it StrategyItemAction) User Requsts b) - e) described the main activity mode of the program. To work with only today's DayLog , for each category. 2nd priority activity is retrieval of history, which typically will be From all categories, from day x to day y; Get all StrategyDailyLog. Questions First, does the overall layout look sound? I'm worried to see that there are so many relationships in all directions, connecting everything. Is this normal, or does it look like trouble? StrategyItem is made to represent an m:m relationship. Is it correct as I noted 1:m / 1:1 (marked red) ? StrategyItemTimeLog and ItemTimeLog; Logs values that both need to be retrieved together, when retreiving a StrategyItem. Reason I separated is that the first one is strategy-specific, and several strategies can reference same item. So I thought not to duplicate those values that are not dependent no strategy, but only on the item. Hence I also dragged out the LogTime, as it seems to be the only parameter to unite the logs. But this all looks quite disturbing with those 3 tables. Does it make sense at all? Or you have suggestion? Pink circles shows my vague attempt of Aggregate Root Paths. I've been thinking in terms of "what entity is responsible for delete". Though I'm unsure about the actual root. I think it's Category. Does it make sense related to User Requests described above?

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xDocklet, Maven and Hibernate

- by Vinothbabu

I am having some trouble setting up xDocklet and getting this error. Error resolving version for plugin 'xdoclet:maven2-xdoclet2-plugin' from the repositories <pluginRepositories> <pluginRepository> <id>codehaus-plugins</id> <url>http://dist.codehaus.org/</url> <layout>legacy</layout> <snapshots> <enabled>true</enabled> </snapshots> <releases> <enabled>true</enabled> </releases> </pluginRepository> </pluginRepositories> <plugin> <groupId>xdoclet</groupId> <artifactId>maven2-xdoclet2-plugin</artifactId> <executions> <execution> <id>xdoclet</id> <phase>generate-sources</phase> <goals> <goal>xdoclet</goal> </goals> </execution> </executions> <dependencies> <dependency> <groupId>xdoclet-plugins</groupId> <artifactId>xdoclet-plugin-qtags</artifactId> <version>1.0.4-SNAPSHOT</version> </dependency> <dependency> <groupId>xdoclet-plugins</groupId> <artifactId>xdoclet-taglib-qtags</artifactId> <version>1.0.4-SNAPSHOT</version> </dependency> </dependencies> <goals> <goal>xdoclet</goal> </goals> <configuration> <configs> <config> <components> <component> <classname>org.xdoclet.plugin.qtags.impl.QTagImplPlugin</classname> </component> <component> <classname>org.xdoclet.plugin.qtags.impl.QTagLibraryPlugin</classname> <params> <packagereplace>org.xdoclet.plugin.${xdoclet.plugin.namespace}.qtags</packagereplace> </params> </component> <component> <classname>org.xdoclet.plugin.qtags.doclipse.QTagDoclipsePlugin</classname> <params> <filereplace>qtags.xml</filereplace> <namespace>${xdoclet.plugin.namespace}</namespace> </params> </component> <component> <classname>org.xdoclet.plugin.qtags.confluence.QTagConfluencePlugin</classname> <params> <destdir>${project.build.directory}/tag-doc</destdir> <namespace>${xdoclet.plugin.namespace}</namespace> <filereplace>${xdoclet.plugin.namespace}.confluence</filereplace> </params> </component> </components> <includes>**/*.java</includes> <params> <destdir>${project.build.directory}/generated-resources/xdoclet</destdir> </params> </config> </configs> </configuration> </plugin> Some of my questions. Would you recommend me with going with xDocklet. Is there any alternative for it? Is it one of the best way, as hbm's does get generated automatically. Any suggestions on the way how my Java Objects should get persisted in the DB? Any good tutorials over xDocklet Maven and Hibernate. I am using xDocklet to generate HBM's automatically by annotating my POJO's.

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Separation of presentation and business logic in PHP

- by Markus Ossi

I am programming my first real PHP website and am wondering how to make my code more readable to myself. The reference book I am using is PHP and MySQL Web Development 4th ed. The aforementioned book gives three approaches to separating logic and content: include files function or class API template system I haven't chosen any of these yet, as wrapping my brains around these concepts is taking some time. However, my code has become some hybrid of the first two as I am just copy-pasting away here and modifying as I go. On presentation side, all of my pages have these common elements: header, top navigation, sidebar navigation, content, right sidebar and footer. The function-based examples in the book suggest that I could have these display functions that handle all the presentation example. So, my page code will be like this: display_header(); display_navigation(); display_content(); display_footer(); However, I don't like this because the examples in the book have these print statements with HTML and PHP mixed up like this: echo "<tr bgcolor=\"".$color."\"><td><a href=\"".$url."\">" ... I would rather like to have HTML with some PHP in the middle, not the other way round. I am thinking of making my pages so that at the beginning of my page, I will fetch all the data from database and put it in arrays. I will also get the data for variables. If there are any errors in any of these processes, I will put them into error strings. Then, at the HTML code, I will loop through these arrays using foreach and display the content. In some cases, there will be some variables that will be shown. If there is an error variable that is set, I will display that at the proper position. (As a side note: The thing I do not understand is that in most example code, if some database query or whatnot gives an error, there is always: else echo 'Error'; This baffles me, because when the example code gives an error, it is sometimes echoed out even before the HTML has started...) For people who have used ASP.NET, I have gotten somewhat used to the code-behind files and lblError and I am trying to do something similar here. The thing I haven't figured out is how could I do this "do logic first, then presentation" thing so that I would not have to replicate for example the navigation logic and navigation presentation in all of the pages. Should I do some include files or could I use functions here but a little bit differently? Are there any good articles where these "styles" of separating presentation and logic are explained a little bit more thoroughly. The book I have only has one paragraph about this stuff. What I am thinking is that I am talking about some concepts or ways of doing PHP programming here, but I just don't know the terms for them yet. I know this isn't a straight forward question, I just need some help in organizing my thoughts.

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Internet Explorer not loading stylesheet.

- by Antarr Byrd

I have a page that uses css. I works fine in firefox but when I open in IE there appears to be no styling. <!DOCTYPE html> <html> <head> <title>MySite</title> <%= stylesheet_link_tag :all %> <%= javascript_include_tag :defaults %> <%= csrf_meta_tag %> </head> <body> <p> <nav> <ul> <li> <a href="#">Login</a> </li> <li> <a href="#">Blog</a> </li> <li> <a href="#">Contact Us </a> </li> <li> <a href="#">Help</a> </li> <li> <a href="#">Trends</a> </li> <li> <a href="#">Your Privacy!</a> </li> <li> <a href="#">Terms of Use</a> </li> <li> <a href="#">mySite.com</a> </li> </ul> </nav> </p> <%= yield %> </body> <aside style ="float:right; font-size:x-small;background:#ffffff;"> <center> Local Areas </center> <% @states.each do |state| %> <ul> <a href= "/states"> <li> <%= state.name %> </li> </a> </ul> <% end %> </aside> <footer> </footer> </html>

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What are the principles of developing web-applications with action-based java frameworks?

- by Roman

Background I'm going to develop a new web-application with java. It's not very big or very complex and I have enough time until it'll "officially" start. I have some JSF/Facelets development background (about half a year). And I also have some expirience with JSP+JSTL. In self-educational purpose (and also in order to find the best solution) I want to prototype the new project with one of action-based frameworks. Actually, I will choose between Spring MVC and Stripes. Problem In order to get correct impression about action-based frameworks (in comparison with JSF) I want to be sure that I use them correctly (in bigger or lesser extent). So, here I list some most-frequent tasks (at least for me) and describe how I solve them with JSF. I want to know how they should be solved with action-based framework (or separately with Spring MVC and Stripes if there is any difference for concrete task). Rendering content: I can apply ready-to-use component from standard jsf libraries (core and html) or from 3rd-party libs (like RichFaces). I can combine simple components and I can easily create my own components which are based on standard components. Rendering data (primitive or reference types) in the correct format: Each component allow to specify a converter for transforming data in both ways (to render and to send to the server). Converter is, as usual, a simple class with 2 small methods. Site navigation: I specify a set of navigation-cases in faces-config.xml. Then I specify action-attribute of a link (or a button) which should match one or more of navigation cases. The best match is choosen by JSF. Implementing flow (multiform wizards for example): I'm using JSF 1.2 so I use Apache Orchestra for the flow (conversation) scope. Form processing: I have a pretty standard java-bean (backing bean in JSF terms) with some scope. I 'map' form fields on this bean properties. If everything goes well (no exceptions and validation is passed) then all these properties are set with values from the form fields. Then I can call one method (specified in button's action attribute) to execute some logic and return string which should much one of my navigation cases to go to the next screen. Forms validation: I can create custom validator (or choose from existing) and add it to almost each component. 3rd-party libraries have sets of custom ajax-validators. Standard validators work only after page is submitted. Actually, I don't like how validation in JSF works. Too much magic there. Many standard components (or maybe all of them) have predefined validation and it's impossible to disable it (Maybe not always, but I met many problems with it). Ajax support: many 3rd-party libraries (MyFaces, IceFaces, OpenFaces, AnotherPrefixFaces...) have strong ajax support and it works pretty well. Until you meet a problem. Too much magic there as well. It's very difficult to make it work if it doesn't work but you've done right as it's described in the manual. User-friendly URLs: people say that there are some libraries for that exist. And it can be done with filters as well. But I've never tried. It seems too complex for the first look. Thanks in advance for explaning how these items (or some of them) can be done with action-based framework.

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Getting code-first Entity Framework to build tables on SQL Azure

- by NER1808

I am new the code-first Entity Framework. I have tried a few things now, but can't get EF to construct any tables in the my SQL Azure database. Can anyone advise of some steps and settings I should check. The membership provider has no problems create it's tables. I have added the PersistSecurityInfo=True in the connection string. The connection string is using the main user account for the server. When I implement the tables in the database using sql everything works fine. I have the following in the WebRole.cs //Initialize the database Database.SetInitializer<ReykerSCPContext>(new DbInitializer()); My DbInitializer (which does not get run before I get a "Invalid object name 'dbo.ClientAccountIFAs'." when I try to access the table for the first time. Sometime after startup. public class DbInitializer:DropCreateDatabaseIfModelChanges<ReykerSCPContext> { protected override void Seed(ReykerSCPContext context) { using (context) { //Add Doc Types context.DocTypes.Add(new DocType() { DocTypeId = 1, Description = "Statement" }); context.DocTypes.Add(new DocType() { DocTypeId = 2, Description = "Contract note" }); context.DocTypes.Add(new DocType() { DocTypeId = 3, Description = "Notification" }); context.DocTypes.Add(new DocType() { DocTypeId = 4, Description = "Invoice" }); context.DocTypes.Add(new DocType() { DocTypeId = 5, Description = "Document" }); context.DocTypes.Add(new DocType() { DocTypeId = 6, Description = "Newsletter" }); context.DocTypes.Add(new DocType() { DocTypeId = 7, Description = "Terms and Conditions" }); //Add ReykerAccounttypes context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 1, Description = "ISA" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 2, Description = "Trading" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 3, Description = "SIPP" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 4, Description = "CTF" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 5, Description = "JISA" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 6, Description = "Direct" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 7, Description = "ISA & Direct" }); //Save the changes context.SaveChanges(); } and my DBContext class looks like public class ReykerSCPContext : DbContext { //set the connection explicitly public ReykerSCPContext():base("ReykerSCPContext"){} //define tables public DbSet<ClientAccountIFA> ClientAccountIFAs { get; set; } public DbSet<Document> Documents { get; set; } public DbSet<DocType> DocTypes { get; set; } public DbSet<ReykerAccountType> ReykerAccountTypes { get; set; } protected override void OnModelCreating(DbModelBuilder modelBuilder) { //Runs when creating the model. Can use to define special relationships, such as many-to-many. } The code used to access the is public List<ClientAccountIFA> GetAllClientAccountIFAs() { using (DataContext) { var caiCollection = from c in DataContext.ClientAccountIFAs select c; return caiCollection.ToList(); } } and it errors on the last line. Help!

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Effective optimization strategies on modern C++ compilers

- by user168715

I'm working on scientific code that is very performance-critical. An initial version of the code has been written and tested, and now, with profiler in hand, it's time to start shaving cycles from the hot spots. It's well-known that some optimizations, e.g. loop unrolling, are handled these days much more effectively by the compiler than by a programmer meddling by hand. Which techniques are still worthwhile? Obviously, I'll run everything I try through a profiler, but if there's conventional wisdom as to what tends to work and what doesn't, it would save me significant time. I know that optimization is very compiler- and architecture- dependent. I'm using Intel's C++ compiler targeting the Core 2 Duo, but I'm also interested in what works well for gcc, or for "any modern compiler." Here are some concrete ideas I'm considering: Is there any benefit to replacing STL containers/algorithms with hand-rolled ones? In particular, my program includes a very large priority queue (currently a std::priority_queue) whose manipulation is taking a lot of total time. Is this something worth looking into, or is the STL implementation already likely the fastest possible? Along similar lines, for std::vectors whose needed sizes are unknown but have a reasonably small upper bound, is it profitable to replace them with statically-allocated arrays? I've found that dynamic memory allocation is often a severe bottleneck, and that eliminating it can lead to significant speedups. As a consequence I'm interesting in the performance tradeoffs of returning large temporary data structures by value vs. returning by pointer vs. passing the result in by reference. Is there a way to reliably determine whether or not the compiler will use RVO for a given method (assuming the caller doesn't need to modify the result, of course)? How cache-aware do compilers tend to be? For example, is it worth looking into reordering nested loops? Given the scientific nature of the program, floating-point numbers are used everywhere. A significant bottleneck in my code used to be conversions from floating point to integers: the compiler would emit code to save the current rounding mode, change it, perform the conversion, then restore the old rounding mode --- even though nothing in the program ever changed the rounding mode! Disabling this behavior significantly sped up my code. Are there any similar floating-point-related gotchas I should be aware of? One consequence of C++ being compiled and linked separately is that the compiler is unable to do what would seem to be very simple optimizations, such as move method calls like strlen() out of the termination conditions of loop. Are there any optimization like this one that I should look out for because they can't be done by the compiler and must be done by hand? On the flip side, are there any techniques I should avoid because they are likely to interfere with the compiler's ability to automatically optimize code? Lastly, to nip certain kinds of answers in the bud: I understand that optimization has a cost in terms of complexity, reliability, and maintainability. For this particular application, increased performance is worth these costs. I understand that the best optimizations are often to improve the high-level algorithms, and this has already been done.

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Moving from MySQL to MySQLi? I have the code here but I don't get it

- by MuqMan

I have posted the code there, please help me out as I am a newbie, I don't know much in terms of deprecation and stuff. <?php session_start(); include('settings.php'); $issub = $_POST['issub']; if($issub == "yes") { require('settings.php'); $dbcon = mysql_connect($dbhost, $dbuser, $dbpword); if(!dbcon) { die('Could not connect'.mysql_error()); } $selectdb = mysql_select_db($db, $dbcon); $formset = 'yes'; $val = 0; $user = trim($_POST['username'], ' '); $luser = mysql_real_escape_string($user); $password = $_POST['password']; $lpassword = mysql_real_escape_string($password); $selectdb; $userq = mysql_query("SELECT user FROM users WHERE user='".$luser."'"); $userresult = @mysql_result($userq, 0); //echo $userresult; if($userresult == $user) { $val = $val + 1; $usercorrect = 'yes'; } else { $usercorrect = 'no'; } $dbselect; $passwordq = mysql_query("SELECT password FROM users where user='".$luser."'"); $passresult = @mysql_result($passwordq, 0); if($passresult == sha1($password)) { $val = $val + 1; $passcorrect = 'yes'; } else { $passcorrect = 'no'; } if ($val == 2) { $_SESSION['loggedin'] = 'yes'; $_SESSION['uloggedin'] = $user; header('location: logged.php'); } }?> <?php ini_set('display_errors', 1); require('testinclude.php'); ?> <body> <div id="loginform"> <form action="/login.php" method="post" > <input type="hidden" name="issub" value="yes" /> <?php if($usercorrect == 'no') { echo '<span class="required"><i><small>The email address or password you entered is incorrect, please try again.</a></small></i></span>'; } ?> <br /> email: <?php if ($issub == 'yes') { if($user == null){ echo '<br /><span class="required"><i><small>Please enter your email address</a></small></i></span>'; } } ?> <br /><input type="text" name="username" id="usename" /> <br /> password: <br /><input type="password" name="password" id="password" /> <br /> <input type="submit" value="login" /> </form> <div> </body>

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replaceAll() method using parameter from text file

- by Herman Plani Ginting

i have a collection of raw text in a table in database, i need to replace some words in this collection using a set of words. i put all the term to be replace and its substitutes in a text file as below min=admin lelet=lambat lemot=lambat nii=nih ntu=itu and so on. i have successfully initiate a variabel of File and Scanner to read the collection of the term and its substitutes. i loop all the dataset and save the raw text in a string in the same loop i loop all the term collection and save its row to a string name 'pattern', and split the pattern into two string named 'term' and 'replacer' in this loop i initiate a new string which its value is the string from the dataset modified by replaceAll(term,replacer) end loop for term collection then i insert the new string to another table in database end loop for dataset i do it manualy as below replaceAll("min","admin") and its works but its really something to code it manually for almost 2000 terms to be replace it. anyone ever face this kind of really something.. i really need a help now desperate :( package sentimenrepo; import javax.swing.*; import java.sql.*; import java.io.*; //import java.util.HashMap; import java.util.Scanner; //import java.util.Map; /** * * @author herman */ public class synonimReplaceV2 extends SwingWorker { protected Object doInBackground() throws Exception { new skripsisentimen.sentimenttwitter().setVisible(true); Integer row = 0; File synonimV2 = new File("synV2/catatan_kata_sinonim.txt"); String newTweet = ""; DB db = new DB(); Connection conn = db.dbConnect("jdbc:mysql://localhost:3306/tweet", "root", ""); try{ Statement select = conn.createStatement(); select.executeQuery("select * from synonimtweet"); ResultSet RS = select.getResultSet(); Scanner scSynV2 = new Scanner(synonimV2); while(RS.next()){ row++; String no = RS.getString("no"); String tweet = " "+ RS.getString("tweet"); String published = RS.getString("published"); String label = RS.getString("label"); clean2 cleanv2 = new clean2(); newTweet = cleanv2.cleanTweet(tweet); try{ Statement insert = conn.createStatement(); insert.executeUpdate("INSERT INTO synonimtweet_v2(no,tweet,published,label) values('" +no+"','"+newTweet+"','"+published+"','"+label+"')"); String current = skripsisentimen.sentimenttwitter.txtAreaResult.getText(); skripsisentimen.sentimenttwitter.txtAreaResult.setText(current+"\n"+row+"original : "+tweet+"\n"+newTweet+"\n______________________\n"); skripsisentimen.sentimenttwitter.lblStat.setText(row+" tweet read"); skripsisentimen.sentimenttwitter.txtAreaResult.setCaretPosition(skripsisentimen.sentimenttwitter.txtAreaResult.getText().length() - 1); }catch(Exception e){ skripsisentimen.sentimenttwitter.lblStat.setText(e.getMessage()); } skripsisentimen.sentimenttwitter.lblStat.setText(e.getMessage()); } }catch(Exception e){ skripsisentimen.sentimenttwitter.lblStat.setText(e.getMessage()); } return row; } class clean2{ public clean2(){} public String cleanTweet(String tweet){ File synonimV2 = new File("synV2/catatan_kata_sinonim.txt"); String pattern = ""; String term = ""; String replacer = ""; String newTweet=""; try{ Scanner scSynV2 = new Scanner(synonimV2); while(scSynV2.hasNext()){ pattern = scSynV2.next(); term = pattern.split("=")[0]; replacer = pattern.split("=")[1]; newTweet = tweet.replace(term, replacer); } }catch(Exception e){ e.printStackTrace(); } System.out.println(newTweet+"\n"+tweet); return newTweet; } } }

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How to select table column names in a view and pass to controller in rails?

- by zachd1_618

So I am new to Rails, and OO programming in general. I have some grasp of the MVC architecture. My goal is to make a (nearly) completely dynamic plug-and-play plotting web server. I am fairly confused with params, forms, and select helpers. What I want to do is use Rails drop downs to basically pass parameters as strings to my controller, which will use the params to select certain column data from my database and plot it dynamically. I have the latter part of the task working, but I can't seem to pass values from my view to controller. For simplicity's sake, say my database schema looks like this: --------------Plot--------------- |____x____|____y1____|____y2____| | 1 | 1 | 1 | | 2 | 2 | 4 | | 3 | 3 | 9 | | 4 | 4 | 16 | | 5 | 5 | 25 | ... and in my Model, I have dynamic selector scopes that will let me select just certain columns of data: in Plot.rb class Plot < ActiveRecord::Base scope :select_var, lambda {|varname| select(varname)} scope :between_x, lambda {|x1,x2| where("x BETWEEN ? and ?","#{x1}","#{x2}")} So this way, I can call: irb>>@p1 = Plot.select_var(['x','y1']).between_x(1,3) and get in return a class where @p1.x and @p1.y1 are my only attributes, only for values between x=1 to x=4, which I dynamically plot. I want to start off in a view (plot/index), where I can dynamically select which variable names (table column names), and which rows from the database to fetch and plot. The problem is, most select helpers don't seem to work with columns in the database, only rows. So to select columns, I first get an array of column names that exist in my database with a function I wrote. Plots Controller def index d=Plot.first @tags = d.list_vars end So @tags = ['x','y1','y2'] Then in my plot/index.html.erb I try to use a drop down to select wich variables I send back to the controller. index.html.erb <%= select_tag( :variable, options_for_select(@plots.first.list_vars,:name,:multiple=>:true) )%> <%= button_to 'Plot now!', :controller =>"plots/plot_vars", :variable => params[:variable]%> Finally, in the controller again Plots controller ... def plot_vars @plot_data=Plot.select_vars([params[:variable]]) end The problem is everytime I try this (or one of a hundred variations thereof), the params[:variable] is nill. How can I use a drop down to pass a parameter with string variable names to the controller? Sorry its so long, I have been struggling with this for about a month now. :-( I think my biggest problem is that this setup doesn't really match the Rails architecture. I don't have "users" and "articles" as individual entities. I really have a data structure, not a data object. Trying to work with the structure in terms of data object speak is not necessarily the easiest thing to do I think. For background: My actual database has about 250 columns and a couple million rows, and they get changed and modified from time to time. I know I can make the database smarter, but its not worth it on my end. I work at a scientific institute where there are a ton of projects with databases just like this. Each one has a web developer that spends months setting up a web interface and their own janky plotting setups. I want to make this completely dynamic, as a plug-and-play solution so all you have to do is specify your database connection, and this rails setup will automatically show and plot which data you want in it. I am more of a sequential programmer and number cruncher, as are many people here. I think this project could be very helpful in the end, but its difficult to figure out for me right now.

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SOAP Service Request C#

- by user3728352

I have this code that tries to send a request to a soap server, I'm new to soap so i am not sure if the terms i am using are correct or not please correct me I am wrong. Basically i am accessing a web service method named getUserDomain via soap request Here is the code: public void CallWebService() { var _url = "https://....com/QcXmlWebService/QcXmlWebService.asmx?wsdl"; var _action = "https://....com/QcXmlWebService/QcXmlWebService.asmx?op=GetUserDomains"; XmlDocument soapEnvelopeXml = CreateSoapEnvelope(); HttpWebRequest webRequest = CreateWebRequest(_url, _action); InsertSoapEnvelopeIntoWebRequest(soapEnvelopeXml, webRequest); webRequest.BeginGetResponse(null, null); // begin async call to web request. IAsyncResult asyncResult = webRequest.BeginGetResponse(null, null); // suspend this thread until call is complete. You might want to // do something usefull here like update your UI. asyncResult.AsyncWaitHandle.WaitOne(); // get the response from the completed web request. string soapResult; using (WebResponse webResponse = webRequest.EndGetResponse(asyncResult)) { using (StreamReader rd = new StreamReader(webResponse.GetResponseStream())) { soapResult = rd.ReadToEnd(); } Console.Write(soapResult); } } private HttpWebRequest CreateWebRequest(string url, string action) { HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(url); webRequest.Headers.Add("SOAPAction", action); webRequest.ContentType = "text/xml;charset=\"utf-8\""; webRequest.Accept = "text/xml"; webRequest.Method = "POST"; return webRequest; } private XmlDocument CreateSoapEnvelope() { XmlDocument soapEnvelop = new XmlDocument(); string oRequest = ""; oRequest = @"<soap:Envelope xmlns:soap=""http://www.w3.org/2003/05/soap-envelope"" xmlns:qcx=""http://smething.com/QCXML"">"; oRequest = oRequest + "<soap:Header/>"; oRequest = oRequest + "<soap:Body>"; oRequest = oRequest + "<qcx:GetUserDomains>"; oRequest = oRequest + "<qcx:inputXml><![CDATA["; oRequest = oRequest + "<GetUserDomains>"; oRequest = oRequest + "<login>"; oRequest = oRequest + "<domain_name>MBB_BTS</domain_name>"; oRequest = oRequest + "<project_name>WCDMA_BTS_IV</project_name>"; oRequest = oRequest + "<user_name>user</user_name>"; oRequest = oRequest + "<password>pass</password>"; oRequest = oRequest + "</login>"; oRequest = oRequest + "</GetUserDomains>"; oRequest = oRequest + " ]]>"; oRequest = oRequest + "</qcx:inputXml>"; oRequest = oRequest + "</qcx:GetUserDomains>"; oRequest = oRequest + "</soap:Body>"; oRequest = oRequest + "</soap:Envelope>"; soapEnvelop.LoadXml(oRequest); return soapEnvelop; } private void InsertSoapEnvelopeIntoWebRequest(XmlDocument soapEnvelopeXml, HttpWebRequest webRequest) { using (Stream stream = webRequest.GetRequestStream()) { soapEnvelopeXml.Save(stream); } } This code i have seen somewhere in stack overflow before as an answer but i couldn't get it to work... The error im getting is threw exception System.net.webexception. the remote server returned an error :(500) internal server Thanks

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