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• JSF 2.0 Dynamic Views

  - by Robe Eleckers

  Hello, I'm working on a web project which uses JSF 2.0, PrimeFaces and PrettyFaces as main frameworks / libraries. The pages have the following (common) structure: Header, Content, Footer. Header: The Header always contains the same menu. This menu is a custom component, which generates a recursive html <ul><li> list containing <a href="url"> html links, this is all rendered with a custom renderer. The link looks like 'domain.com/website/datatable.xhtml?ref=2'. Where the ref=2 used to load the correct content from the database. I use prettyfaces to store this request value in a backingbean. Question 1: Is it ok to render the <a href> links myself, or should I better add an HTMLCommandLink from my UIComponent and render that in the encodeBegin/End? Question 2: I think passing variables like this is not really the JSF 2.0 style, how to do this in a better way? Content: The content contains dynamic data. It can be a (primefaces) datatable, build with dynamic data from the database. It can also be a text page, also loaded from the database. Or a series of graphs. You got the point, it's dynamic. The content is based on the link pressed in the header menu. If the content is of type datatable, then I put the ref=2 variable to a DataTableBean (via prettyfaces), which then loads the correct datatable from the database. If the content is of type chart, I'll put it on the ChartBean. Question 3: Is this a normal setup? Ideally I would like to update my content via Ajax. I hope it's clear :)

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• Form not sending full data

  - by gAMBOOKa

  I have a form with over 50 input fields. The input fields are divided into 5 jquery jabs within the form container. Here's a sample of what it looks like: <form action="admin/save" method="post" enctype="multipart/form-data"> <input type="hidden" name="type" value="department" /> <input type="hidden" name="id" value="21" /> <div id="tabs"> <ul> <li><a href="#tab-1">Tab 1</a><li> <li><a href="#tab-2">Tab 2</a><li> <li><a href="#tab-3">Tab 3</a><li> </ul> <div id="tab-1"> <label>Name</label> <input type="text" name="user-name" /> </div> <div id="tab-2"> <label>Address</label> <input type="text" name="user-address" /> </div> <div id="tab-3"> <label>Phone</label> <input type="text" name="user-phone" /> </div> </div> <input type="submit" value="Send" /> </form> I'm using PHP's Kohana framework, so admin maps to a controller, and save maps to the method action_save. When I output the $_POST variables in action_save, only 'type' and 'id' show up, all the other fields don't seem to submit their data. What could I be doing wrong?

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• PHP - Best practice to retain form values across postback

  - by Adam

  Hello, Complete PHP novice here, almost all my previous work was in ASP.NET. I am now working on a PHP project, and the first rock I have stumbled upon is retaining values across postback. For the most simple yet still realistic example, i have 10 dropdowns. They are not even databound yet, as that is my next step. They are simple dropdowns. I have my entire page inclosed in a tag. the onclick() event for each dropdown, calls a javascript function that will populate the corrosponding dropdowns hidden element, with the dropdowns selected value. Then, upon page reload, if that hidden value is not empty, i set the selected option = that of my hidden. This works great for a single postback. However, when another dropdown is changed, the original 1'st dropdown loses its value, due to its corrosponding hidden value losing its value as well! This draws me to look into using querystring, or sessions, or... some other idea. Could someone point me in the right direction, as to which option is the best in my situation? I am a PHP novice, however I am being required to do some pretty intense stuff for my skill level, so I need something flexable and preferribly somewhat easy to use. Thanks! -----edit----- A little more clarification on my question :) When i say 'PostBack' I am referring to the page/form being submitted. The control is passed back to the server, and the HTML/PHP code is executed again. As for the dropdowns & hiddens, the reason I used hidden variables to retain the "selected value" or "selected index", is so that when the page is submitted, I am able to redraw the dropdown with the previous selection, instead of defaulting back to the first index. When I use the $_POST[] command, I am unable to retrieve the dropdown by name, but I am able to retrieve the hidden value by name. This is why upon dropdown-changed event, I call javascript which sets the selected value from the dropdown into its corrosponding hidden.

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• Polymorphic Queue

  - by metdos

  Hello Everyone, I'm trying to implement a Polymorphic Queue. Here is my trial: QQueue <Request *> requests; while(...) { QString line = QString::fromUtf8(client->readLine()).trimmed(); if(...)){ Request *request=new Request(); request->tcpMessage=line.toUtf8(); request->decodeFromTcpMessage(); //this initialize variables in request using tcpMessage if(request->requestType==REQUEST_LOGIN){ LoginRequest loginRequest; request=&loginRequest; request->tcpMessage=line.toUtf8(); request->decodeFromTcpMessage(); requests.enqueue(request); } //Here pointers in "requests" do not point to objects I created above, and I noticed that their destructors are also called. LoginRequest *loginRequest2=dynamic_cast<LoginRequest *>(requests.dequeue()); loginRequest2->decodeFromTcpMessage(); } } Unfortunately, I could not manage to make work Polymorphic Queue with this code because of the reason I mentioned in second comment.I guess, I need to use smart-pointers, but how? I'm open to any improvement of my code or a new implementation of polymorphic queue. Thanks.

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• How do I apply a "template" or "skeleton" of code in C# here?

  - by Scott Stafford

  In my business layer, I need many, many methods that follow the pattern: public BusinessClass PropertyName { get { if (this.m_LocallyCachedValue == null) { if (this.Record == null) { this.m_LocallyCachedValue = new BusinessClass( this.Database, this.PropertyId); } else { this.m_LocallyCachedValue = new BusinessClass( this.Database, this.Record.ForeignKeyName); } } return this.m_LocallyCachedValue; } } I am still learning C#, and I'm trying to figure out the best way to write this pattern once and add methods to each business layer class that follow this pattern with the proper types and variable names substituted. BusinessClass is a typename that must be substituted, and PropertyName, PropertyId, ForeignKeyName, and m_LocallyCachedValue are all variables that should be substituted for. Are attributes usable here? Do I need reflection? How do I write the skeleton I provided in one place and then just write a line or two containing the substitution parameters and get the pattern to propagate itself? EDIT: Modified my misleading title -- I am hoping to find a solution that doesn't involve code generation or copy/paste techniques, and rather to be able to write the skeleton of the code once in a base class in some form and have it be "instantiated" into lots of subclasses as the accessor for various properties. EDIT: Here is my solution, as suggested but left unimplemented by the chosen answerer. // I'll write many of these... public BusinessClass PropertyName { get { return GetSingleRelation(ref this.m_LocallyCachedValue, this.PropertyId, "ForeignKeyName"); } } // That all call this. public TBusinessClass GetSingleRelation<TBusinessClass>( ref TBusinessClass cachedField, int fieldId, string contextFieldName) { if (cachedField == null) { if (this.Record == null) { ConstructorInfo ci = typeof(TBusinessClass).GetConstructor( new Type[] { this.Database.GetType(), typeof(int) }); cachedField = (TBusinessClass)ci.Invoke( new object[] { this.Database, fieldId }); } else { var obj = this.Record.GetType().GetProperty(objName).GetValue( this.Record, null); ConstructorInfo ci = typeof(TBusinessClass).GetConstructor( new Type[] { this.Database.GetType(), obj.GetType()}); cachedField = (TBusinessClass)ci.Invoke( new object[] { this.Database, obj }); } } return cachedField; }

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• proper use of volatile keyword

  - by luke

  I think i have a pretty good idea about the volatile keyword in java, but i'm thinking about re-factoring some code and i thought it would be a good idea to use it. i have a class that is basically working as a DB Cache. it holds a bunch of objects that it has read from a database, serves requests for those objects, and then occasionally refreshes the database (based on a timeout). Heres the skeleton public class Cache { private HashMap mappings =....; private long last_update_time; private void loadMappingsFromDB() { //.... } private void checkLoad() { if(System.currentTimeMillis() - last_update_time > TIMEOUT) loadMappingsFromDB(); } public Data get(ID id) { checkLoad(); //.. look it up } } So the concern is that loadMappingsFromDB could be a high latency operation and thats not acceptable, So initially i thought that i could spin up a thread on cache startup and then just have it sleep and then update the cache in the background. But then i would need to synchronize my class (or the map). and then i would just be trading an occasional big pause for making every cache access slower. Then i thought why not use volatile i could define the map reference as volatile private volatile HashMap mappings =....; and then in get (or anywhere else that uses the mappings variable) i would just make a local copy of the reference: public Data get(ID id) { HashMap local = mappings; //.. look it up using local } and then the background thread would just load into a temp table and then swap the references in the class HashMap tmp; //load tmp from DB mappings = tmp;//swap variables forcing write barrier Does this approach make sense? and is it actually thread-safe?

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• image not displaying in midlet

  - by user316843

  Hello all,am new here. i have a slight problem; PLease look at the following code and tell me if am doing something wrong because the image is not displaying. i have made it really small so it should fit but its not displaying. i have images displaying in other screens but this main midlet would not. Here is the code: import java.io.IOException; import javax.microedition.midlet.*; import javax.microedition.lcdui.*; /** * @author jay */ public class WShop extends MIDlet implements CommandListener { /* Declare display variables*/ private Form mainForm; private Display display; private Command OK,Exit,wView, mView, myView; /* */ Categories categories = new Categories(this); Image image; public WShop() { /* initialize Screen and Command buttons that will be used when the application starts in the class constructor*/ mainForm = new Form("Wind Shopper"); OK = new Command("OK", Command.OK, 2); Exit = new Command("Exit", Command.EXIT, 0); wview= new Command("wview", Command.OK, 0); mview= new Command("mview", Command.OK, 0); try { /* retrieving the main image of the application*/ image = Image.createImage("/main.png"); } catch (IOException ex) { ex.printStackTrace(); } mainForm.addCommand(OK); mainForm.addCommand(Exit); mainForm.addCommand(wView); mainForm.addCommand(mView); mainForm.setCommandListener(this); } public void startApp() { /* checks to see if the display is currently empty and then sets it to the current screen */ if (display == null) { display = Display.getDisplay(this); } display.setCurrent(mainForm); } /* paused state of the application*/ public void pauseApp() { } /* Destroy Midlet state*/ public void destroyApp(boolean unconditional) { } Thanks in advance.

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• Pointer problem in C for char*

  - by egebilmuh

  Hi guys, i use pointer for holding name and research lab property. But when i print the existing Vertex ,when i print the vertex, i cant see so -called attributes properly. For example though real value of name is "lancelot" , i see it as wrong such as "asdasdasdasd" struct vertex { int value; char*name; char* researchLab; struct vertex *next; struct edge *list; }; void GRAPHinsertV(Graph G, int value,char*name,char*researchLab) { //create new Vertex. Vertex newV = malloc(sizeof newV); // set value of new variable to which belongs the person. newV->value = value; newV->name=name; newV->researchLab=researchLab; newV->next = G->head; newV->list = NULL; G->head = newV; G->V++; } /*** The method creates new person. **/ void createNewPerson(Graph G) { int id; char name[30]; char researchLab[30]; // get requeired variables. printf("Enter id of the person to be added.\n"); scanf("%d",&id); printf("Enter name of the person to be added.\n"); scanf("%s",name); printf("Enter researc lab of the person to be added\n"); scanf("%s",researchLab); // insert the people to the social network. GRAPHinsertV(G,id,name,researchLab); } void ListAllPeople(Graph G) { Vertex tmp; Edge list; for(tmp = G->head;tmp!=NULL;tmp=tmp->next) { fprintf(stdout,"V:%d\t%s\t%s\n",tmp->value,tmp->name,tmp->researchLab); } system("pause"); }

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• Can PHP dissect its own syntax?

  - by Nathan Long

  Can PHP dissect its own syntax? For example, I'd like to write a function that takes in an input like $object->attribute and says to itself: OK, he's giving me $foo->bar, which means he must think that $foo is an object that has a property called bar. Before I try accessing bar and potentially get a 'Trying to get property of non-object' error, let me check whether $foo is even an object. The end goal is to echo a value if it is set, and fail silently if not. I want to avoid repetition like this: <input value="<? if(is_object($foo) && is_set($foo->bar)){ echo $foo->bar; }?> "/> ...and to avoid writing a function that does the above, but has to have the object and attribute passed in separately, like this: <input value="<? echoAttribute($foo,'bar') ?>" /> ...but to instead write something which: preserves the object-attribute syntax is flexible: can also handle array keys or regular variables Like this: <input value="<? echoIfSet($foo->bar); ?> /> <input value="<? echoIfSet($baz['buzz']); ?> /> <input value="<? echoIfSet($moo); ?> /> But this all depends on PHP being able to tell me "what kind of thing am I asking for when I say $object->attribute or $array[$key]", so that my function can handle each according to its own type. Is this possible?

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• Chord Chart - Skip to key with a click

  - by Juan Gonzales

  I have a chord chart app that basically can transpose a chord chart up and down throughout the keys, but now I would like to expand that app and allow someone to pick a key and automatically go to that key upon a click event using a function in javascript or jquery. Can someone help me figure this out? The logic seems simple enough, but I'm just not sure how to implement it. Here are my current functions that allow the user to transpose up and down... var match; var chords = ['C','C#','D','D#','E','F','F#','G','G#','A','A#','B','C','Db','D','Eb','E','F','Gb','G','Ab','A','Bb','B','C']; var chords2 = ['C','Db','D','Eb','E','F','Gb','G','Ab','A','Bb','B','C','C#','D','D#','E','F','F#','G','G#','A','A#','C']; var chordRegex = /(?:C#|D#|F#|G#|A#|Db|Eb|Gb|Ab|Bb|C|D|E|F|G|A|B)/g; function transposeUp(x) { $('.chord'+x).each(function(){ ///// initializes variables ///// var currentChord = $(this).text(); // gatheres each object var output = ""; var parts = currentChord.split(chordRegex); var index = 0; ///////////////////////////////// while (match = chordRegex.exec(currentChord)){ var chordIndex = chords2.indexOf(match[0]); output += parts[index++] + chords[chordIndex+1]; } output += parts[index]; $(this).text(output); }); } function transposeDown(x){ $('.chord'+x).each(function(){ var currentChord = $(this).text(); // gatheres each object var output = ""; var parts = currentChord.split(chordRegex); var index = 0; while (match = chordRegex.exec(currentChord)){ var chordIndex = chords2.indexOf(match[0],1); //var chordIndex = $.inArray(match[0], chords, -1); output += parts[index++] + chords2[chordIndex-1]; } output += parts[index]; $(this).text(output); }); } Any help is appreciated. Answer will be accepted! Thank You

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• How to use sessions in PDO?

  - by Byakugan

  I am still redoing and getting rid of old mysql_* commands in my code. I tried to transfer my session login form old code and this is what I got so far: public function login($user, $password) { if (!empty($user) && !empty($password)) { $password = $web->doHash($user, $password); // in this function is (return sha1(strtoupper($user).':'.strtoupper($password)) $stmt = $db_login->prepare("SELECT * FROM account WHERE username=:user AND pass_hash=:password"); $stmt->bindValue(':user', $user, PDO::PARAM_STR); $stmt->bindValue(':password', $password, PDO::PARAM_STR); $stmt->execute(); $rows = $stmt->rowCount(); if ($rows > 0) { $results_login = $stmt->fetch(PDO::FETCH_ASSOC); $_SESSION['user_name'] = $results_login['username']; $_SESSION['user_id'] = $results_login['id']; return true; } else { return false; } } else { return false; } } After that I am using checks if user logged on site: public function isLogged() { return (!empty($_SESSION['user_id']) && !empty($_SESSION['user_name'])); } But it seems - this function returns always empty because $_SESSION does not exists in PDO? And of course logout is used in this form on my sites: public function logout() { unset($_SESSION['user_id']); unset($_SESSION['user_name']); } But I think PDO has different way of handling session? I did not find any so what is it can i somehow add $_SESSION in PDO withou changing code much? I am using variables $_SESSION['user_name'] and $_SESSION['user_id'] in all over my web project. Summary: 1) How to use sessions in PDO correctly? 2) What is difference between using $stmt->fetch(PDO::FETCH_ASSOC); and $stmt->fetchAll(); Thank you.

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• ajax to php to curl and back..

  - by pfunc

  I am trying to make an ajax call to a php script. The php script calls an rss feed using curl, gets the data, and returns the data to the funciton. I keep getting an error "Warning: Wrong parameter count for curl_error() in" .... Here is my php code:1 $ch = curl_init() or die(curl_error()); curl_setopt($ch, CURLOPT_URL, $feed); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); $data1 = curl_exec($ch) or die(curl_error()); echo $data1; and the ajax call: $.ajax({ url: "getSingleFeed.php", type: "POST", data: "feedURL=" + window.feedURL, success: function(feed){ alert(feed); }}); I tested all the variables, they are being passed correctly, I can echo them out. But this line: $data1 = curl_exec($ch) or die(curl_error()); is what is giving me the error. I am doing the same thing with curl on other pages, just without ajax, and it is working fine. Is there anything special I need to do with ajax to do this?

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• Intel IA-32 Assembly

  - by Kay

  I'm having a bit of difficulty converting the following java code into Intel IA-32 Assembly: class Person() { char name [8]; int age; void printName() {...} static void printAdults(Person [] list) { for(int k = 0; k < 100; k++){ if (list[k].age >= 18) { list[k].printName(); } } } } My attempt is: Person: push ebp; save callers ebp mov ebp, esp; setup new ebp push esi; esi will hold name push ebx; ebx will hold list push ecx; ecx will hold k init: mov esi, [ebp + 8]; mov ebx, [ebp + 12]; mov ecx, 0; k=0 forloop: cmp ecx, 100; jge end; if k>= 100 then break forloop cmp [ebx + 4 * ecx], 18 ; jl auxloop; if list[k].age < 18 then go to auxloop jmp printName; printName: auxloop: inc ecx; jmp forloop; end: pop ecx; pop ebx; pop esi; pop ebp; Is my code correct? NOTE: I'm not allowed to use global variables.

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• Is it possible to accept a button tag to be in some range iphone sdk

  - by neha

  Hi all, In my application I'm doing dynamic resizing of cells and label in it depending upon the text in it. I'm adding button to cells in uitableview. I'm taking the label instance and button instance in a new label and button variable respectively and setting their frames to arrange them properly after resizing. if(cel==nil) { //some code original_label=[[UILabel alloc]init]; original_label.tag=111; //SOME MORE CODE GOES HERE original_button=[[UIButton alloc]init]; original_button.tag=222; //SOME MORE CODE GOES HERE } new_label=(UILabel *) [cell viewWithTag:111]; //This' how I'm taking the label instance on cell and below button instance on cell in new variables new_button = (UIButton * ) [cell viewWithTag:222]; Earlier I kept the tags of all the buttons on cells same, so it was easier to get button instances on cells properly and were being arranged properly. But now I want to recognize these buttons separately as I'm adding some functionality on button_click. I'm giving the buttons that are added to the cells incremental tags[1,2,3...9 and so on]. Now, how can I take these button tags in some range like[suppose 1-9]? Can anybody help? Thanks in advance.

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• connecting to MySQL using JDBC in eclipse

  - by Noona

  Hello, So I want to create a JDBC connection to MySQL server that is installed on my pc, here are the steps, I installed MySQL with the username and password "root", downloaded mysql-connector-java and from theere I coped the JAR "mysql-connector-java-5.1.12-bin" to "C:\Sun\SDK\jdk\jre\lib\ext", I then added it as an external JAR in my project in eclipse, now in my class I have this code: public void initialiseDatabase() { try { // Load the Driver class. Class.forName("com.mysql.jdbc.Driver"); //Create the connection using the static getConnection method databaseConnection = DriverManager.getConnection (databaseUrl+databaseName, dbUserName, dbPassword); sqlStatement = databaseConnection.createStatement(); } catch (SQLException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();} } (this is going to be psuedocode cause I am reading from a properties file and don't want the one helping me reading through long lines of code from main to figure out all the variables), where databaseUrl = "127.0.0.1" dbUserName = "root" dbPassword = "root" databaseName = "MySQL" //this one I am not sure of, do I need to create it or is it set inherenrly? now the MySQL server is up and running, but when I call the method initialiseDatabase the following exception is thrown: "java.sql.SQLException: No suitable driver found for rootroot at java.sql.DriverManager.getConnection(Unknown Source) at java.sql.DriverManager.getConnection(Unknown Source) at Proxy$JDBCConnection.initialiseDatabase(Proxy.java:721)" when line 721 is: sqlStatement = databaseConnection.createStatement(); Where have I gone wrong? thanks

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• Boost::thread mutex issue: Try to lock, access violation

  - by user1419305

  I am currently learning how to multithread with c++, and for that im using boost::thread. I'm using it for a simple gameengine, running three threads. Two of the threads are reading and writing to the same variables, which are stored inside something i call PrimitiveObjects, basicly balls, plates, boxes etc. But i cant really get it to work, i think the problem is that the two threads are trying to access the same memorylocation at the same time, i have tried to avoid this using mutex locks, but for now im having no luck, this works some times, but if i spam it, i end up with this exception: First-chance exception at 0x00cbfef9 in TTTTT.exe: 0xC0000005: Access violation reading location 0xdddddded. Unhandled exception at 0x77d315de in TTTTT.exe: 0xC0000005: Access violation reading location 0xdddddded. These are the functions inside the object that im using for this, and the debugger is also blaming them for the exception. void PrimitiveObj::setPos(glm::vec3 in){ boost::mutex mDisposingMutex; boost::try_mutex::scoped_try_lock lock(mDisposingMutex); if ( lock) { position = in; boost::try_mutex::scoped_try_lock unlock(mDisposingMutex); } } glm::vec3 PrimitiveObj::getPos(){ boost::mutex myMutex; boost::try_mutex::scoped_try_lock lock(myMutex); if ( lock) { glm::vec3 curPos = position; boost::try_mutex::scoped_try_lock unlock(myMutex); return curPos; } return glm::vec3(0,0,0); } Any ideas?

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• Combining multiple rows into one row, Oracle

  - by Torbjørn

  Hi. I'm working with a database which is created in Oracle and used in a GIS-software through SDE. One of my colleuges is going to make some statistics out of this database and I'm not capable of finding a reasonable SQL-query for getting the data. I have two tables, one with registrations and one with registrationdetails. It's a one to many relationship, so the registration can have one or more details connected to it (no maximum number). table: Registration RegistrationID Date TotLenght 1 01.01.2010 5 2 01.02.2010 15 3 05.02.2009 10 2.table: RegistrationDetail DetailID RegistrationID Owner Type Distance 1 1 TD UB 1,5 2 1 AB US 2 3 1 TD UQ 4 4 2 AB UQ 13 5 2 AB UR 13,1 6 3 TD US 5 I want the resulting selection to be something like this: RegistrationID Date TotLenght DetailID RegistrationID Owner Type Distance DetailID RegistrationID Owner Type Distance DetailID RegistrationID Owner Type Distance 1 01.01.2010 5 1 1 TD UB 1,5 2 1 AB US 2 3 1 TD UQ 4 2 01.02.2010 15 4 2 AB UQ 13 5 2 AB UR 13,1 3 05.02.2009 10 6 3 TD US 5 With a normal join I get one row per each registration and detail. Can anyone help me with this? I don't have administrator-rights for the database, so I can't create any tables or variables. If it's possible, I could copy the tables into Access.

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• How to prevent parallel builds per build configuration across multiple Build Agents

  - by vanslly

  I have many build configurations in TeamCity, each servicing a large project. In the past if a build is kicked off the Build Agent could be busy for up to 20min! In order to improve throughput I installed a second Build Agent on the same machine such that if a build run is kicked off by say Build Agent 1 and it is busy for 20min and someone from another project makes a change then Build Agent 2 can do the build for the other project without needing to wait on the current build run to finish. All was well until two successive check-ins resulted in both Build Agents running a build for a single build configuration in parallel. Since some resources are shared, IIS directories & databases, I don't want a single build configuration to run on both Build Agents in parallel. How can I ensure a build isn't triggered if a build is currently running for that build configuration on a different build agent? One way seems to involve environmental variables and ensuring a 50/50 split by Build Agent in terms of build configuration compatibility, but that seems a little clunky.

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• SQL command to get field of a maximum value, without making two select

  - by António Capelo

  I'm starting to learn SQL and I'm working on this exercise: I have a "books" table which holds the info on every book (including price and genre ID). I need to get the name of the genre which has the highest average price. I suppose that I first need to group the prices by genre and then retrieve the name of the highest.. I know that I can get the results GENRE VS COST with the following: select b.genre, round(avg(b.price),2) as cost from books b group by b.genre; My question is, to get the genre with the highest AVG price from that result, do I have to make: select aux.genre from ( select b.genre, round(avg(b.price),2) as cost from books b group by b.genre ) aux where aux.cost = (select max(aux.cost) from ( select b.genre, round(avg(b.price),2) as cost from books l group by b.genre ) aux); Is it bad practice or isn't there another way? I get the correct result but I'm not confortable with creating two times the same selection. I'm not using PL SQL so I can't use variables or anything like that.. Any help will be appreciated. Thanks in advance!

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• How can "today's date" be varied for unit testing purposes?

  - by ck

  I use VS2008 targetting .NET 2.0 Framework, and, just in case, no I can't change this :) I have a DateCalculator class. Its method GetNextExpirationDate attempts to determine the next expiration, internally using DateTime.Today as a baseline date. As I was writing unit tests, I realized that I wanted to test GetNextExpirationDate for different 'today' dates. What's the best way to do this? Here are some alternatives I've considered: Expose a property/overloaded method with argument baselineDate and only use it from the unit test. In actual client code, disregard the property/overloaded method in favour of the method that defaults baselineDate to DateTime.Today. I'm reluctant to do this as it makes the public interface of the DateCalculator class awkward. Create a protected field called baselineDate that is internally set to DateTime.Today. When testing, derive a DateCalculatorForTesting from DateCalculator and set baslineDate via the constructor. It keeps the public interface clean, but still isn't great - baselineDate was made protected and a derived class is required, both solely for testing. Use extension methods. I tried this after adding the ExtensionAttribute, then realized it wouldn't work because extension methods can't access private/protected variables. I initially thought this was really quite an elegant solution. :( I'd be interested in hearing what others think.

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• Basic compile issue with QT4

  - by Cobus Kruger

  I've been trying to get a dead simple listing from a university textbook to compile with the newest QT SDK for Windows I downloaded last night. After struggling through the regular nonsense (no make.bat, need to manually add environment variables and so on) I am finally at the point where I can build. But only one of the two libraries seem to work. The .pro file I use is dead simple: SUBDIRS += utils \ dataobjects TEMPLATE = subdirs In each of these two subfolders I have the source for a library. Running QMAKE generates a makefile and running Make runs through all the preliminaries and then fails on the g++ call: g++ -enable-stdcall-fixup -Wl,-enable-auto-import -Wl,-enable-runtime-pseudo-reloc --out-implib,libdataobjects.a -shared -mthreads -Wl -Wl,--out-implib,c:\Users\Cobus\workspace\lib\libdataobjects.a -o ..\..\lib\dataobjects.dll object_script.dataobjects.Debug -L"c:\Users\Cobus\Portab~1\Qt\2010.02.1\qt\lib" -LC:\Users\Cobus\workspace\lib -lutils -lQtXmld4 -lQtGuid4 -lQtCored4 c:/users/cobus/portab~1/qt/2010.02.1/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../../mingw32/bin/ld.exe: cannot find -lutils The problem seems to be right near the end of the command line, where -lutils is added, indicating that there is a library by the name of utils. While I would have expected to see that, you'll notice the library names after --out include lib in the name, so they become libutils and libdataobjects. I have tried to figure out why this is happening, to no avail. Anyone have an idea what's going on?

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• Please help us non-C++ developers understand what RAII is

  - by Charlie Flowers

  Another question I thought for sure would have been asked before, but I don't see it in the "Related Questions" list. Could you C++ developers please give us a good description of what RAII is, why it is important, and whether or not it might have any relevance to other languages? I do know a little bit. I believe it stands for "Resource Acquisition is Initialization". However, that name doesn't jive with my (possibly incorrect) understanding of what RAII is: I get the impression that RAII is a way of initializing objects on the stack such that, when those variables go out of scope, the destructors will automatically be called causing the resources to be cleaned up. So why isn't that called "using the stack to trigger cleanup" (UTSTTC:)? How do you get from there to "RAII"? And how can you make something on the stack that will cause the cleanup of something that lives on the heap? Also, are there cases where you can't use RAII? Do you ever find yourself wishing for garbage collection? At least a garbage collector you could use for some objects while letting others be managed? Thanks.

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• Accessing functions in a swf-file through javascript [chatroulette.com]

  - by RadiantHeart

  Lately I have been interested in the code behind chatroulette.com. As you probably know it is a peer-to-peer webcam-chat-service written in actionscript, as I understand. What i have been wondering about is weather its possible to extract the ip-address of whomever you are currently communicating with. I have seen services that do that, but they require that you install a program that runs alongside on your computer sniffing UDP-packages. I was wondering if there was a simpler method. What I do know is that the javascript on the page communicates with the application via "ExternalInterface". On this area I am pretty much a novice but according to my limited understanding you cant get information from the flash-application unless you have configured a listener for a call from javascript and then attach a callback to that event. Is this correct or can you access public functions and variables directly through javascript? There is for example a public function like this: public function get outgoingAddress():String{ return (this.__info.outgoingAddress); } Can it be accessed directly through javascript? If it cant be done so easily, is it possible to decompile the .swf-file, change it (add some functions) and recompile it and run it instead? I am hoping someone can satisfy my curiosity here. Here are two links to a decompiled version of the swf-file. The first with line numbering and one without. With line numbering ˜ 3.5 Mbyte Without line numbering ˜ 2.1 Mbyte

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• String Manipulation: Splitting Delimitted Data

  - by Milli Szabo

  I need to split some info from a asterisk delimitted data. Data Format: NAME*ADRESS LINE1*ADDRESS LINE2 Rules: 1. Name should be always present 2. Address Line 1 and 2 might not be 3. There should be always three asterisks. Samples: MR JONES A ORTEGA*ADDRESS 1*ADDRESS2* Name: MR JONES A ORTEGA Address Line1: ADDRESS 1 Address Line2: ADDRESS 2 A PAUL*ADDR1** Name: A PAUL Address Line1: ADDR1 Address Line2: Not Given My algo is: 1. Iterate through the characters in the line 2. Store all chars in a temp variables until first * is found. Reject the data if no char is found before first occurence of asterisk. If some chars found, use it as the name. 3. Same as step 2 for finding address line 1 and 2 except that this won't reject the data if no char is found My algo looks ugly. The code looks uglier. Spliting using //* doesn't work either since name can be replaced with address line 1 if the data was *Address 1*Address2. Any suggestion?

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• Optimizing processing and management of large Java data arrays

  - by mikera

  I'm writing some pretty CPU-intensive, concurrent numerical code that will process large amounts of data stored in Java arrays (e.g. lots of double[100000]s). Some of the algorithms might run millions of times over several days so getting maximum steady-state performance is a high priority. In essence, each algorithm is a Java object that has an method API something like: public double[] runMyAlgorithm(double[] inputData); or alternatively a reference could be passed to the array to store the output data: public runMyAlgorithm(double[] inputData, double[] outputData); Given this requirement, I'm trying to determine the optimal strategy for allocating / managing array space. Frequently the algorithms will need large amounts of temporary storage space. They will also take large arrays as input and create large arrays as output. Among the options I am considering are: Always allocate new arrays as local variables whenever they are needed (e.g. new double[100000]). Probably the simplest approach, but will produce a lot of garbage. Pre-allocate temporary arrays and store them as final fields in the algorithm object - big downside would be that this would mean that only one thread could run the algorithm at any one time. Keep pre-allocated temporary arrays in ThreadLocal storage, so that a thread can use a fixed amount of temporary array space whenever it needs it. ThreadLocal would be required since multiple threads will be running the same algorithm simultaneously. Pass around lots of arrays as parameters (including the temporary arrays for the algorithm to use). Not good since it will make the algorithm API extremely ugly if the caller has to be responsible for providing temporary array space.... Allocate extremely large arrays (e.g. double[10000000]) but also provide the algorithm with offsets into the array so that different threads will use a different area of the array independently. Will obviously require some code to manage the offsets and allocation of the array ranges. Any thoughts on which approach would be best (and why)?

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