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• Peculiar JRE behaviour running RMI server under load, should I worry?

  - by darri

  I've been developing a minimalistic Java rich client CRUD application framework for the past few years, mostly as a hobby but also actively using it to write applications for my current employer. The framework provides database access to clients either via a local JDBC based connection or a lightweight RMI server. Last night I started a load testing application, which ran 100 headless clients, bombarding the server with requests, each client waiting only 1 - 2 seconds between running simple use cases, consisting of selecting records along with associated detail records from a simple e-store database (Chinook). This morning when I looked at the telemetry results from the server profiling session I noticed something which to me seemed strange (and made me keep the setup running for the remainder of the day), I don't really know what conclusions to draw from it. Here are the results: Memory GC activity Threads CPU load Interesting, right? So the question is, is this normal or erratic? Is this simply the JRE (1.6.0_03 on Windows XP) doing it's thing (perhaps related to the JRE configuration) or is my framework design somehow causing this? Running the server against MySQL as opposed to an embedded H2 database does not affect the pattern. I am leaving out the details of my server design, but I'll be happy to elaborate if this behaviour is deemed erratic.

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• why my form is doing postback when i am calling asynchronously?

  - by Abu Hamzah

  i am using simple asp.net webpage with few fields on it and when the user click on submit button i am calling asynchronously and posting the data. BUT, my whole page is posting back and i dont even see the message that i am trying to display if my data got posted succfully. here is my page. Requester Page Name: <asp:Label runat="server" ID='Label4' >Host Name:</asp:Label> <asp:TextBox ID="txtHost" runat='server'></asp:TextBox> <asp:Label runat="server" ID='Label2' >Start Date:</asp:Label> <asp:TextBox ID="txtStartDate" runat='server' ></asp:TextBox> <asp:Label runat="server" ID='Label6' >End Date:</asp:Label> <asp:TextBox ID="txtEndDate" runat='server' ></asp:TextBox> <ul> <li> <button id="btnCancel" name="btnCancel" type="button"> Cancel</button></li> <li> <button id="btnReset" name="btnReset" type="reset"> Reset</button></li> <li> <button id="btnSubmit" name="btnSubmit" type="submit"> Submit</button></li> </ul> </p> </form> </div> //Store new Contract Request Methods function processCompletedContactStore(response) { if (!response) { showErrorMsg('No Contacts Returned'); return; } else { if (response.Message == 'update') { $("#status").fadeTo(500, 1, function() { $(this).html("Updated successfully!").fadeTo(500, 150); }) } } }

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• getline with ints C++

  - by Mdjon26

  I have a file 0 3 2 1 2 3 4 5 6 6 8 1 Where the first number for each line is the row, the second number is the column, and the third number is the data contained in that row, column. This will be a given [8][8] array so I have already initialized everything to 0, but how can I store each of these data values? For example, I want [0][3] =2 and [1][2] = 3. I would like to keep track of the line on which I found that row, col, and data value. So, how can I correctly insert these values into my 2-D array? int rowcol[8][8]; for (int i=0; i < 9; i++) for (int j=0; j < 9; j++) { rowcol[i][j] =0; } ifstream myfile; int nums; myfile.open(text.c_str()); while (!myfile.eof()) { myfile >> nums; numbers.push_back(nums); } for (int i=0; i < numbers.size(); i++) { //Not sure what the best approach here would be and I'm not even sure if I should have done a vector... }

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• Where to start with the development of first database driven Web App (long question)?

  - by Ryan

  Hi all, I've decided to develop a database driven web app, but I'm not sure where to start. The end goal of the project is three-fold: 1) to learn new technologies and practices, 2) deliver an unsolicited demo to management that would show how information that the company stores as office documents spread across a cumbersome network folder structure can be consolidated and made easier to access and maintain and 3) show my co-workers how Test Drive Development and prototyping via class diagrams can be very useful and reduces future maintenance headaches. I think this ends up being a basic CMS to which I have generated a set of features, see below. 1) Create a database to store the site structure (organized as a tree with a 'project group'-project structure). 2) Pull the site structure from the database and display as a tree using basic front end technologies. 3) Add administrator privileges/tools for modifying the site structure. 4) Auto create required sub pages* when an admin adds a new project. 4.1) There will be several sub pages under each project and the content for each sub page is different. 5) add user privileges for assigning read and write privileges to sub pages. What I would like to do is use Test Driven Development and class diagramming as part of my process for developing this project. My problem; I'm not sure where to start. I have read on Unit Testing and UML, but never used them in practice. Also, having never worked with databases before, how to I incorporate these items into the models and test units? Thank you all in advance for your expertise.

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• rails + paperclip: Is a generic "Attachment" model a good idea?

  - by egarcia

  On my application I've several things with attachments on them, using paperclip. Clients have one logo. Stores can have one or more pictures. These pictures, in addition, can have other information such as the date in which they were taken. Products can have one or more pictures of them, categorized (from the font, from the back, etc). For now, each one of my Models has its own "paperclip-fields" (Client has_attached_file) or has_many models that have attached files (Store has_many StorePictures, Product has_many ProductPictures) My client has also told me that in the future we might be adding more attachments to the system (i.e. pdf documents for the clients to download). My application has a rather complex authorization system implemented with declarative_authorization. One can not, for example, download pictures from a product he's not allowed to 'see'. I'm considering re-factoring my code so I can have a generic "Attachment" model. So any model can has_many :attachments. With this context, does it sound like a good idea? Or should I continue making Foos and FooPictures?

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• How to strip everything between a key phrase and an ending tag?

  - by user3620142

  I am trying to strip everything between a key phrase and ending tag but for some reason it is not working. I always get blank data. I've tried many different ways but no luck. Basically I have a script that connect to IMAP and store emails into MySQL as service tickets. It works great but I am trying to strip off everything except for user reply because currently if a user reply to an email it re-inserts the entire email into MySQL. I added a key phrase at the top of all outgoing emails . Structure is as below: --Reply below this line to respond-- ------------------------------------------------------------------------------------ Email body message... When replying to the message, it becomes: New Message reply...... --Reply below this line to respond-- old message body. I would only like to insert the new reply message only. This is what I've got so far: $message = strip_tags($message, "<br><div><p><u><hr></section>"); $message=preg_replace("</p>", "br /", $message); $message=preg_replace('#--REPLY above this line to respond--(.*?)</section>)#s', ' ', $message); $message=clean("<br/><hr><u>Received On $rep_date / $from_email</u><br><br/>$message"); It inserts the Received On date and From but $message is blank. If I remove $message=preg_replace('#--REPLY above this line to respond--(.*?)</section>)#s', ' ', $message); it inserts the entire email. Any suggestion on what i am doing wrong?

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• Need help: input int from console and pass it into method in different class and do math

  - by christophe

  i'm a beginner, Need help, Please!!! I want to read optional number "a" from console and then store it in variable to use as passing to a different class (different .java file). and pint the sum separetely by optional inputting. How do i code the 2 classes? thanks /* * DemoApp.java */ public class DemoApp { public static void main(String[] args) { Scanner input = new Scanner(System.in); int a; System.out.println("Input one of the following 3 numbers: 100, 200, 300"); System.out.print("Enter: "); a = input.nextInt(); TestApplication testapp = new TestApplication(); testapp.test(a); } } /* * TestApplication.java * */ public class TestApplication { private int a; public void test(int a) { this.a = a; // TODO: where to get the "a"? (entered by users from console) System.out.println("The number_a was passed in: "+a); } protected void printNum() throws Exception { int num; switch (a) { case 100: num = num + 10; break; case 200: num = num + 20; break; case 300: num = num + 30; break; default: // TODO: unexpected number input. throw(); break; } System.out.println("I got a sum number"+num); } }

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• How to use the values from session variables in jsp pages that got saved using @Scope("session") in the mvc controllers

  - by droidsites

  Doing a web site using spring mvc. I added a SignupController to handle all the sign up related requests. Once user signup I am adding that to a session using @Scope("session"). Below is the SignupController code, SignupController.java @Controller @Scope("session") public class SignupController { @Autowired SignupServiceInter signUpService; private static final Logger logger = Logger.getLogger(SignupController.class); private String sessionUser; @RequestMapping("/SignupService") public ModelAndView signUp(@RequestParam("userid") String userId, @RequestParam("password") String password,@RequestParam("mailid") String emailId){ logger.debug(" userId:"+userId+"::Password::"+password+"::"); String signupResult; try { signUpService.registerUser(userId, password,emailId); sessionUser = userId; //adding the sign up user to the session return new ModelAndView("userHomePage","loginResult","Success"); //Navigate to user Home page if everything goes right } catch (UserExistsException e) { signupResult = e.toString(); return new ModelAndView("signUp","loginResult", signupResult); //Navigate to signUp page back if user does not exist } } } I am using "sessionUser" variable to store the signed up User Id. My understanding is that when I use @Scope("session") for the controller all the instance variables will added to HttpSession. So by that understanding I tried to access this "SessionUser" in userHomePage.jsp as, userHomepage.jsp Welcome to <%=session.getAttribute("sessionUser")%> But it throws null. So my question is how to use the values from session variables in jsp pages that got saved using @Scope("session") in the mvc controllers. Note: My work around is that pass that signed User Id to jsp page through ModelAndView, but it seems passing the value like these among the pages takes me back to managing state among pages using QueryStrings days.

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• No result when Rally.data.WsapiDataStore lacks permissions

  - by user1195996

  I'm calling Ext.create('Rally.data.WsapiDataStore', params), and looking for results with the load event. I'm requesting a number of objects across programs that the user may or may not have read permission for. This works fine for queries where the user has permissions. But in the case where the user does not have permission and presumably gets zero results back, the load event does not seem to fire at all. I would expect it to fire with the unsuccessful flag or else to return with empty results. Since I don't know that the request has failed, my program waits and waits. How can I tell if a this request fails to return because of security? BTW, looking at the network stats, I believe all my requests get a "200 OK" status back. Here is the method I use to create the various data stores: _createDataStore: function(params) { this.openRequests++; var createParams = { model: params.type, autoLoad: true, // So I can later determine which query type it is, and which program requestType: params.requestType == undefined ? params.type : params.requestType, program: this.program, listeners: { load: this._onDataLoaded, scope: this }, filters: params.filters, pageSize: params.pageSize, fetch: params.fetch, context: { project: this.project, projectScopeUp: false, projectScopeDown: true }, pageSize: 1 // We only need the count }; console.log('_createDataStore', this.program, createParams.requestType); Ext.create('Rally.data.WsapiDataStore', createParams); }, And here is the _onDataLoaded method: _onDataLoaded: function(store, data, successB) { console.log('_onDataLoaded', this.program, successB); ... I only see this function called for those queries for which the account has permissions.

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• Adding validations without knowing the fields

  - by Frexuz

  My example form <% form_for @ad do |f| %> <%= f.error_messages %> <p> <%= f.label :ad_type_id %><br /> <%= f.collection_select(:ad_type_id, AdType.all, :id, :name) %> </p> <p> <% @ad.ad_properties.each do |property| %> <%= property.name %>: <% f.fields_for :ad_values do |value_field| %> <%= value_field.text_field :ad_id, :value => @ad.id %> <%= value_field.text_field :ad_property_id, :value => property.id %> <%= value_field.text_field :value %> <% end %><br /><br /> <% end %> </p> <p> <%= f.label :description %><br /> <%= f.text_area :description %> </p> <p><%= f.submit %></p> <% end %> Explanation: Ad has many properties. I can add new properties at any time (it's a normal model). Lets say the Ad is of the type 'hotel'. Then I would add properties like 'stars' and 'breakfast_included' Then I store each of these properties' values in a separate model. And all this works fine with my form above. My problem: These fields are not validated because I can't know what their names are. I need to add validations dynamically somehow. My thought: #Before the normal validations kick in def add_validations self.properties.each do |property| property.add_validation :whatever #somehow :) end end How could I do this?

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• New to J2EE; architecture suggestions for a service/daemon?

  - by Kate

  I am brand new to the J2EE world. As an exercise to try and familiarize myself with J2EE, I'm trying to create a tiered web-app, but I'm getting a little stuck on what the best way is to spin up a service in the background that does work. Paramters of the service: It must open and hold a socket connection and receive information from the connected server. There is a 1-to-1 correlation between a user and a new socket connection. So the idea is the user presses a button on the web-page, and somewhere on the server a socket connection is opened. For the remainder of the users session (or until the user presses some sort of disconnect button) the socket remains open and pushes received information to some sort of centralized store that servlets can query and return to the user via AJAX. Is there a J2EE type way to handle this situation? Naturally what I would think to do is to just write a Java application that listens on a port that the servlets can connect to and spawns new threads that open these sockets, but that seems very ad-hoc to me. (PS: I am also new to Stack Overflow, so forgive me if it takes me some time to figure the site out!)

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• creating a vector with references to some of the elements of another vector

  - by memC

  hi, I have stored instances of class A in a std:vector, vec_A as vec_A.push_back(A(i)). The code is shown below. Now, I want to store references some of the instances of class A (in vec_A) in another vector or another array. For example, if the A.getNumber() returns 4, 7, 2 , I want to put a reference to that instance of A in another vector, say std:vector<A*> filtered_A or an array. Can someone sow me how to do this?? Thanks! class A { public: int getNumber(); A(int val); ~A(){}; private: int num; }; A::A(int val){ num = val; }; int A::getNumber(){ return num; }; int main(){ int i =0; int num; std::vector<A> vec_A; for ( i = 0; i < 10; i++){ vec_A.push_back(A(i)); } std::cout << "\nPress RETURN to continue..."; std::cin.get(); return 0; }

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• Why doesn't Firefox redownload images already on a page?

  - by vvo

  Hello, i just read this article : https://developer.mozilla.org/en/HTTP_Caching_FAQ There's a firefox behavior (and some other browsers i guess) i'd like to understand : if i take any webpage and try to insert the same image multiple times in javascript, the image is only downloaded ONCE even if i specifiy all needed headers to say "do no ever use cache". (see article) I know there are workarounds (like addind query strings to end of urls etc) but why do firefox act like that, if i say that an image do not have to be cached, why is the image still taken from cache when i try to re-insert it ? Plus, what cache is used for this ? (I guess it's the memory cache) Is this behavior the same for dynamic inclusion for example ? ANSWSER IS NO :) I just tested it and the same headers for a js script will make firefox redownload it each time you append the script to the DOM. PS: I know you're wondering WHY i need to do that (appending same image multiple times and force to redownload but this is the way our app works) thank you The good answer is : firefox will store images for the current page load in the memory cache even if you specify he doesnt have to cache them. You can't change this behavior but this is odd because it's not the same for javascript files for example Could someone explain or link to a document describing how firefox cache WORKS?

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• Detect if Download is Complete

  - by user604138

  I have a very simple and standard PHP force download script. How do I check if/when the download has completed in order to notify the user on the clientside? I don't even need to show the progress in real time, I am only interested in the very specific event: "when the download completes". Based on my research, it seems like it would have to be determined from the serverside as there is noondownloadready event and I don't think it is possible to intercept browser events. So it seems that my best bet would be to compare bytes sent to total bytes with some sort of clientside/severside interaction. How would I go about checking the bytes sent from the server for a PHP forced download? is there some sort of global PHP variable that store these data that I can ping with AJAX? <?php header("Content-Type: video/x-msvideo"); header("Content-Disposition: attachment; filename=\"".basename($realpath)."\";"); ... $chunksize = 1 * (1024 * 1024); // how many bytes per chunk if ($size > $chunksize) { $handle = fopen($realpath, 'rb'); $buffer = ''; while (!feof($handle)) { $buffer = fread($handle, $chunksize); echo $buffer; ob_flush(); flush(); } fclose($handle); } else { readfile($realpath); } exit(); ?> The reason I need this: For the project I am working on, it is required that after the download starts, the page redirects to (or displays) a "please wait while the download completes" page. Then, once it is complete, it should redirect to (or display) a "Your download is complete, thank you" page. I am open to other ideas that would achieve the same result.

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• How can I compare the performance of log() and fp division in C++?

  - by Ventzi Zhechev

  Hi, I’m using a log-based class in C++ to store very small floating-point values (as the values otherwise go beyond the scope of double). As I’m performing a large number of multiplications, this has the added benefit of converting the multiplications to sums. However, at a certain point in my algorithm, I need to divide a standard double value by an integer value and than do a *= to a log-based value. I have overloaded the *= operator for my log-based class and the right-hand side value is first converted to a log-based value by running log() and than added to the left-hand side value. Thus the operations actually performed are floating-point division, log() and floating-point summation. My question whether it would be faster to first convert the denominator to a log-based value, which would replace the floating-point division with floating-point subtraction, yielding the following chain of operations: twice log(), floating-point subtraction, floating-point summation. In the end, this boils down to whether floating-point division is faster or slower than log(). I suspect that a common answer would be that this is compiler and architecture dependent, so I’ll say that I use gcc 4.2 from Apple on darwin 10.3.0. Still, I hope to get an answer with a general remark on the speed of these two operators and/or an idea on how to measure the difference myself, as there might be more going on here, e.g. executing the constructors that do the type conversion etc. Cheers!

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• Overhead of calling tiny functions from a tight inner loop? [C++]

  - by John

  Say you see a loop like this one: for(int i=0; i<thing.getParent().getObjectModel().getElements(SOME_TYPE).count(); ++i) { thing.getData().insert( thing.GetData().Count(), thing.getParent().getObjectModel().getElements(SOME_TYPE)[i].getName() ); } if this was Java I'd probably not think twice. But in performance-critical sections of C++, it makes me want to tinker with it... however I don't know if the compiler is smart enough to make it futile. This is a made up example but all it's doing is inserting strings into a container. Please don't assume any of these are STL types, think in general terms about the following: Is having a messy condition in the for loop going to get evaluated each time, or only once? If those get methods are simply returning references to member variables on the objects, will they be inlined away? Would you expect custom [] operators to get optimized at all? In other words is it worth the time (in performance only, not readability) to convert it to something like: ElementContainer &source = thing.getParent().getObjectModel().getElements(SOME_TYPE); int num = source.count(); Store &destination = thing.getData(); for(int i=0;i<num;++i) { destination.insert(thing.GetData().Count(), source[i].getName(); } Remember, this is a tight loop, called millions of times a second. What I wonder is if all this will shave a couple of cycles per loop or something more substantial? Yes I know the quote about "premature optimisation". And I know that profiling is important. But this is a more general question about modern compilers, Visual Studio in particular.

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• table column accepting "0" as a member Id

  - by user682417

  I have two tables one is members table with columns member id , member first name, member last name. I have another table guest passes with columns guest pass id and member id and issue date . I have a list view that will displays guest passes details (I.e) like member name and issue date and I have two text boxes those are for entering member name and issue date . member name text box is auto complete text box that working fine.... but the problem is when I am entering the name that is not in member table at this time it will accept and displays a blank field in list view in member name column and member id is stored as "0" in guest pass table ...... I don't want to display the member name empty blank and I don t want to store "0" in guest pass table and this is the insert statement sql2 = @"INSERT INTO guestpasses(member_Id,guestPass_IssueDate)"; sql2 += " VALUES("; sql2 += "'" + tbCGuestPassesMemberId.Text + "'"; sql2 += ",'" + tbIssueDate.Text + "'"; guestpassmemberId = memberid is there any validation that need to be done can any one suggestions on this pls... and this is the auto complete text box statement sql = @"SELECT member_Id FROM members WHERE concat(member_Firstname,'',member_Lastname) ='" + tbMemberName.Text+"'"; if (dt != null) { if (dt.Rows.Count > 0) { tbCGuestPassesMemberId.Text = Convert.ToInt32(dt.Rows[0] ["member_Id"]).ToString(); } } can any one help me on this ... is there any type of validation with sql query pls help me .....

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• Quick question regarding MVC framework for a java game

  - by Jason

  I have a question regarding the use of the MVC framework for a blackjack game im writing in java. As I understand, my model would be a class that stores the state of the game, and more specifically, each players hand. Within the model class, I would have an array of listeners, which would be notified each time the game state changes (ie a player has drawn a new card). These listeners would be my viewer, which is the class that handles the display of the game. This class would implement the ActionListener interface, and each time the model changes, it would call/"notify" my viewer's actionPerformed method. My question is as follows: I intend to have two JPanels, each devoted to displaying the respective player's hand. As a player draws a new card, a new ImageIcon would be added to the panel. My question is how would the viewer class know what card has been added to the player's hand? I suppose I could store the player's hand before a notify event, and then upon the notification event, compare the new state with the old, to find out what has changed. I'm a complete novice here, so I could be completely wrong, but it seems a bit tedious to do this. Is there a more efficient/common way of detecting what has changed in the model between the before and after state? Another solution would be to redraw the entire panel each time the notification occurs? Would this be a better idea?

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• junit test error - ClassCastException

  - by Josepth Vodary

  When trying to run a junit test I get the following error - java.lang.ClassCastException: business.Factory cannot be cast to services.itemservice.IItemsService at business.ItemManager.get(ItemManager.java:56) at business.ItemMgrTest.testGet(ItemMgrTest.java:49) The specific test that is causing the problem is @Test public void testGet() { Assert.assertTrue(itemmgr.get(items)); } The code it is testing is... public boolean get(Items item) { boolean gotItems = false; Factory factory = Factory.getInstance(); @SuppressWarnings("static-access") IItemsService getItem = (IItemsService)factory.getInstance(); try { getItem.getItems("pens", 15, "red", "gel"); gotItems = true; } catch (ItemNotFoundException e) { // catch e.printStackTrace(); System.out.println("Error - Item Not Found"); } return gotItems; } The test to store items, which is nearly identical, works just fine... The factory class is.. public class Factory { private Factory() {} private static Factory Factory = new Factory(); public static Factory getInstance() {return Factory;} public static IService getService(String serviceName) throws ServiceLoadException { try { Class<?> c = Class.forName(getImplName(serviceName)); return (IService)c.newInstance(); } catch (Exception e) { throw new ServiceLoadException(serviceName + "not loaded"); } } private static String getImplName (String serviceName) throws Exception { java.util.Properties props = new java.util.Properties(); java.io.FileInputStream fis = new java.io.FileInputStream("config\\application.properties"); props.load(fis); fis.close(); return props.getProperty(serviceName); } }

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• Pickled my dictionary from ZODB but i got a less in size one?

  - by Someone Someoneelse

  I use ZODB and i want to copy my 'database_1.fs' file to another 'database_2.fs', so I opened the root dictionary of that 'database_1.fs' and I (pickle.dump) it in a text file. Then I (pickle.load) it in a dictionary-variable, in the end I update the root dictionary of the other 'database_2.fs' with the dictionary-variable. It works, but I wonder why the size of the 'database_1.fs' not equal to the size of the other 'database_2.fs'. They are still copies of each other. def openstorage(store): #opens the database data={} data['file']=filestorage data['db']=DB(data['file']) data['conn']=data['db'].open() data['root']=data['conn'].root() return data def getroot(dicty): return dicty['root'] def closestorage(dicty): #close the database after Saving transaction.commit() dicty['file'].close() dicty['db'].close() dicty['conn'].close() transaction.get().abort() then that's what i do:- import pickle loc1='G:\\database_1.fs' op1=openstorage(loc1) root1=getroot(op1) loc2='G:database_2.fs' op2=openstorage(loc2) root2=getroot(op2) >>> len(root1) 215 >>> len(root2) 0 pickle.dump( root1, open( "save.txt", "wb" )) item=pickle.load( open( "save.txt", "rb" ) ) #now item is a dictionary root2.update(item) closestorage(op1) closestorage(op2) #after I open both of the databases #I get the same keys in both databases #But `database_2.fs` is smaller that `database_2.fs` in size I mean. >>> len(root2)==len(root1)==215 #they have the same keys True Note: (1) there are persistent dictionaries and lists in the original database_1.fs (2) both of them have the same length and the same indexes.

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• Does Entity Framework saves related classes automatically?

  - by herbatnic

  Let's assume that we have such classes public class A{ string someField { get; set; } public virtual B B {get; set; } } public class B { int someIntField {get; set; } [ForeignKey("Id")] [Required] public virtual A A { get; set; } } In code I create new instances for both of them and making relation like: A a = new A () { someField = "abcd"}; B b = new B () { someIntField = 42 }; A.B = b; B.A = a; Should I using DBContext to save both classes like that: using (var db = new myDbContext()) { myDbContext.As.Add(A); myDbContext.Bs.Add(B); myDBContext.SaveChanges(); } Or saving it like that: using (var db = new myDbContext()) { myDbContext.As.Add(A); myDbContext.SaveChanges(); } is enough to store related objects into database?

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• How can I pass an array resulting from a Perl method by reference?

  - by arareko

  Some XML::LibXML methods return arrays instead of references to arrays. Instead of doing this: $self->process_items($xml->findnodes('items/item')); I want to do something like: $self->process_items(\$xml->findnodes('items/item')); So that in process_items() I can dereference the original array instead of creating a copy: sub process_items { my ($self, $items) = @_; foreach my $item (@$items) { # do something... } } I can always store the results of findnodes() into an array and then pass the array reference to my own method, but let's say I want to try a reduced version of my code. Is that the correct syntax for passing the method results or should I use something different? Thanks! EDIT: Now suppose I want to change process_items() to process_item() so I can do stuff on a single element of the referenced array inside a loop. Something like: $self->process_item($_) for ([ $xml->findnodes('items/item') ]); This doesn't work as process_item() is executed only once because a single value is passed to the for loop (the reference to the array from findnodes()). What's the proper way of using $_ in this case?

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• Replacing XML in File from "Document" in Java

  - by poeschlorn

  Hi, after processing my first steps in working with XML in java I am now at the point where I want to update some data in my XML/GPX file... Reaplacing it in my "Document" data type works great :) How here comes the question: how can I store the changed "document"-model back to my file? Do I have to do this by using the standart file-functions (via steams and so on) oder is the a more elegant way to do this? ;-) Here's the code I already worked out, maybe that could help. (the method getParsedXML is just puting the conversion from the file into an extra method) Document tmpDoc = getParsedXML(currentGPX); //XML Parsind tests: // Access to tag attribute <tag attribut="bla"> System.out.println(tmpDoc.getElementsByTagName("wpt").item(0).getAttributes().getNamedItem("lat").getTextContent()); // Access to the value of an child element <a><CHILD>ValueOfChild</CHILD></a> System.out.println(tmpDoc.getElementsByTagName("wpt").item(0).getChildNodes().item(5).getTextContent()); // Replacing access to tag attribute tmpDoc.getElementsByTagName("wpt").item(0).getAttributes().getNamedItem("lat").setTextContent("139.921055008"); System.out.println(tmpDoc.getElementsByTagName("wpt").item(0).getAttributes().getNamedItem("lat").getTextContent()); // Replacing access to child element value tmpDoc.getElementsByTagName("wpt").item(0).getChildNodes().item(5).setTextContent("Cala Sant Vicenç - Mallorca 2"); System.out.println(tmpDoc.getElementsByTagName("wpt").item(0).getChildNodes().item(5).getTextContent());

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• Plugin-like architecture in .NET

  - by devoured elysium

  I'm trying to implement a plug-in like application. I know there are already several solution out there but this is just going to be proof of the concept, nothing more. The idea would be to make the application main application almost featureless by default and then let the plugins know about each other, having them have implement all the needed features. A couple of issues arise: I want the plugins at runtime to know about each other through my application. That wouldn't mean that at code-time they couldn't reference other plugin's assemblies so they could use its interfaces, only that plugin-feature initialization should be always through my main app. For example: if I have both plugins X and Y loaded and Y wants to use X's features, it should "register" its interest though my application to use its features. I'd have to have a kind of "dictionary" in my application where I store all the loaded plugins. After registering for interest in my application, plugin Y would get a reference to X so it could use it. Is this a good approach? When coding plugin Y that uses X, I'd need to reference X's assembly, so I can program against its interface. That has the issue of versioning. What if I code my plugin Y against an outdated version of plugin X? Should I always use a "central" place where all assemblies are, having there always the up to date versions of the assemblies? Are there by chance any books out there that specifically deal with these kinds of designs for .NET? Thanks

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• Create an index only on certain rows in mysql

  - by dhruvbird

  So, I have this funny requirement of creating an index on a table only on a certain set of rows. This is what my table looks like: USER: userid, friendid, created, blah0, blah1, ..., blahN Now, I'd like to create an index on: (userid, friendid, created) but only on those rows where userid = friendid. The reason being that this index is only going to be used to satisfy queries where the WHERE clause contains "userid = friendid". There will be many rows where this is NOT the case, and I really don't want to waste all that extra space on the index. Another option would be to create a table (query table) which is populated on insert/update of this table and create a trigger to do so, but again I am guessing an index on that table would mean that the data would be stored twice. How does mysql store Primary Keys? I mean is the table ordered on the Primary Key or is it ordered by insert order and the PK is like a normal unique index? I checked up on clustered indexes (http://dev.mysql.com/doc/refman/5.0/en/innodb-index-types.html), but it seems only InnoDB supports them. I am using MyISAM (I mention this because then I could have created a clustered index on these 3 fields in the query table). I am basically looking for something like this: ALTER TABLE USERS ADD INDEX (userid, friendid, created) WHERE userid=friendid

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