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  • [Python] name 'OptionGroup' is not defined

    - by Cawas
    Ok, so I made this rookie mistake below, but in my defense I was led to it thanks to how the help about this subject is on python docs, which states how to use optparse. It is actually an error under the gigantic tutorial section. In contrast and to my offense, I may be one of the very few stupid people who can't read very well and pay close attention on what I do. But since this took me so long to discover, I wanted to "document" it here: Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29) >>> from optparse import OptionParser >>> outputGroup = OptionGroup(parser, 'Output handling') Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'OptionGroup' is not defined This is strictly done with examples found on the docs, and you can't find anything about it anywhere, be it that long long docs page, google or stackoverflow. Plus, reading optparse.py shows OptionGroup is there, so that adds to the confusion. I bet it will take less than 1 minute for someone to spot my error. For that I'll only add proper tags and / or modify the title later on. :)

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  • Can't empty JS array....

    - by solefald
    Yes, I am having issues with this very basic (or so it seems) thing. I am pretty new to JS and still trying to get my head around it, but I am pretty familiar with PHP and have never experienced anything like this. I just can not empty this damn array, and stuff keeps getting added to the end every time i run this. I have no idea why, and i am starting to think that it is somehow related to the way chekbox id's are named, but i may be mistaking.... id="alias[1321-213]", id="alias[1128-397]", id="alias[77-5467]" and so on. I have tried sticking checkboxes = []; and checkboxes.length = 0; In every place possible. Right after the beginning of the function, at the end of the function, even outside, right before the function, but it does not help, and the only way to empty this array is to reload the page. Please tell me what I am doing wrong, or at least point me to a place where i can RTFM. I am completely out of ideas here. function() { var checkboxes = new Array(); checkboxes = $(':input[name="checkbox"]'); $.each(checkboxes, function(key, value) { console.log(value.id); alert(value.id); } ); checkboxes.length = 0; } I have also read Mastering Javascript Arrays 3 times to make sure I am not doing something wrong, but still can't figure it out....

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  • Hierarchical object model with property inheritance and event bubbling?

    - by Winston Fassett
    I'm writing a document-based client application and I need a DOM or WPF-like, but non-visual model that: Is a tree composed of elements Can accept an unlimited number of custom properties that get/set any CLR type, including collections. Can inherit their values from their parent Can inherit their default values from an ancestor Can be derived/calculated from other properties, ancestors, or descendants Support event bubbling / tunneling There will be a core set of properties but other plugins may add their own or even create custom documents Supports full inspection by the owning document in order to persist the tree and attributes in an XML format. I realize that's a tall order but I was really hoping there would be something out there to help me get started. Unfortunately WPF DependencyObjects are too closed, proprietary, and coupled to WPF to be of any use as a document model. My needs also have a strong resemblance to the HTML DOM but I haven't been able to find any clean DOM implementations that could be decoupled from HTML or ported to .NET. My current platform is .NET/C# but if anyone knows of anything that might be useful for inspiration or embedding, regardless of the platform, I'd love to know.

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  • Silverlight - how to render image from non-visible data bound user control?

    - by MagicMax
    Hello! I have such situation - I'd like to build timeline control. So I have UserControl and ItemsControl on it (every row represents some person). The ItemsControl contains another ItemsControl as ItemsControl.ItemTemplate - it shows e.g. events for the person arranged by event's date. So it looks as some kind of grid with dates as a column headers and e.g. peoples as row headers. ........................|.2010.01.01.....2010.01.02.....2010.01.03 Adam Smith....|......[some event#1].....[some event#2]...... John Dow.......|...[some event#3].....[some event#4]......... I can have a lot of persons (ItemsControl #1 - 100-200 items) and a lot of events occured by some day (1-10-30 events per person in one day) the problem is that when user scrolls ItemsControl #1/#2 it happened toooo sloooooowwww due to a lot of elements should be rendered in one time (as I have e.g. a bit of text boxes and other elements in description of particular event) Question #1 - how can I improve it? May be somebody knows better way to build such user control? I have to mention that I'm using custom Virtual panel, based on some custom Virtual panel implementation found somewhere in internet... Question #2 - I'd like to make image with help of WriteableBitmap and render data bound control to image and to show image instead of a lot of elements. Problem is that I'm trying to render invisible data bound control (created in code behind) and it has actualWidth/Height equals to zero (so nothing rendered). How can I solve it? Thank you very much for you help!

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  • Templates, and C++ operator for logic: B contained by set A

    - by James Morris
    In C++, I'm looking to implement an operator for selecting items in a list (of type B) based upon B being contained entirely within A. In the book "the logical design of digital computers" by Montgomery Phister jr (published 1958), p54, it says: F11 = A + ~B has two interesting and useful associations, neither of them having much to do with computer design. The first is the logical notation of implication... The second is notation of inclusion... This may be expressed by a familiar looking relation, B < A; or by the statement "B is included in A"; or by the boolean equation F11= A + ~B = 1. My initial implementation was in C. Callbacks were given to the list to use for such operations. An example being a list of ints, and a struct containting two ints, min and max, for selection purposes. There, selection would be based upon B = A-min && B <= A-max. Using C++ and templates, how would you approach this after having implemented a generic list in C using void pointers and callbacks? Is using < as an over-ridden operator for such purposes... <ugh> evil? </ugh> (or by using a class B for the selection criteria, implementing the comparison by overloading ?)

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  • If attacker has original data and encrypted data, can they determine the passphrase?

    - by Brad Cupit
    If an attacker has several distinct items (for example: e-mail addresses) and knows the encrypted value of each item, can the attacker more easily determine the secret passphrase used to encrypt those items? Meaning, can they determine the passphrase without resorting to brute force? This question may sound strange, so let me provide a use-case: User signs up to a site with their e-mail address Server sends that e-mail address a confirmation URL (for example: https://my.app.com/confirmEmailAddress/bill%40yahoo.com) Attacker can guess the confirmation URL and therefore can sign up with someone else's e-mail address, and 'confirm' it without ever having to sign in to that person's e-mail account and see the confirmation URL. This is a problem. Instead of sending the e-mail address plain text in the URL, we'll send it encrypted by a secret passphrase. (I know the attacker could still intercept the e-mail sent by the server, since e-mail are plain text, but bear with me here.) If an attacker then signs up with multiple free e-mail accounts and sees multiple URLs, each with the corresponding encrypted e-mail address, could the attacker more easily determine the passphrase used for encryption? Alternative Solution I could instead send a random number or one-way hash of their e-mail address (plus random salt). This eliminates storing the secret passphrase, but it means I need to store that random number/hash in the database. The original approach above does not require storage in the database. I'm leaning towards the the one-way-hash-stored-in-the-db, but I still would like to know the answer: does having multiple unencrypted e-mail addresses and their encrypted counterparts make it easier to determine the passphrase used?

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  • Java method keyword "final" and its use

    - by Lukas Eder
    When I create complex type hierarchies (several levels, several types per level), I like to use the final keyword on methods implementing some interface declaration. An example: interface Garble { int zork(); } interface Gnarf extends Garble { /** * This is the same as calling {@link #zblah(0)} */ int zblah(); int zblah(int defaultZblah); } And then abstract class AbstractGarble implements Garble { @Override public final int zork() { ... } } abstract class AbstractGnarf extends AbstractGarble implements Gnarf { // Here I absolutely want to fix the default behaviour of zblah // No Gnarf shouldn't be allowed to set 1 as the default, for instance @Override public final int zblah() { return zblah(0); } // This method is not implemented here, but in a subclass @Override public abstract int zblah(int defaultZblah); } I do this for several reasons: It helps me develop the type hierarchy. When I add a class to the hierarchy, it is very clear, what methods I have to implement, and what methods I may not override (in case I forgot the details about the hierarchy) I think overriding concrete stuff is bad according to design principles and patterns, such as the template method pattern. I don't want other developers or my users do it. So the final keyword works perfectly for me. My question is: Why is it used so rarely in the wild? Can you show me some examples / reasons where final (in a similar case to mine) would be very bad?

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  • getting expat to use .dtd for entity replacement in python

    - by nicolas78
    I'm trying to read in an xml file which looks like this <?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE dblp SYSTEM "dblp.dtd"> <dblp> <incollection> <author>Jos&eacute; A. Blakeley</author> </incollection> </dblp> The point that creates the problem looks is the Jos&eacute; A. Blakeley part: The parser calls its character handler twice, once with "Jos", once with " A. Blakeley". Now I understand this may be the correct behaviour if it doesn't know the eacute entity. However, this is defined in the dblp.dtd, which I have. I don't seem to be able to convince expat to use this file, though. All I can say is p = xml.parsers.expat.ParserCreate() # tried with and without following line p.SetParamEntityParsing(xml.parsers.expat.XML_PARAM_ENTITY_PARSING_ALWAYS) p.UseForeignDTD(True) f = open(dblp_file, "r") p.ParseFile(f) but expat still doesn't recognize my entity. Why is there no way to tell expat which DTD to use? I've tried putting the file into the same directory as the XML putting the file into the program's working directory replacing the reference in the xml file by an absolute path What am I missing? Thx.

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  • Who architected / designed C++'s IOStreams, and would it still be considered well-designed by today'

    - by stakx
    First off, it may seem that I'm asking for subjective opinions, but that's not what I'm after. I'd love to hear some well-grounded arguments on this topic. In the hope of getting some insight into how a modern streams / serialization framework ought to be designed, I recently got myself a copy of the book Standard C++ IOStreams and Locales by Angelika Langer and Klaus Kreft. I figured that if IOStreams wasn't well-designed, it wouldn't have made it into the C++ standard library in the first place. After having read various parts of this book, I am starting to have doubts if IOStreams can compare to e.g. the STL from an overall architectural point-of-view. Read e.g. this interview with Alexander Stepanov (the STL's "inventor") to learn about some design decisions that went into the STL. What surprises me in particular: It seems to be unknown who was responsible for IOStreams' overall design (I'd love to read some background information about this — does anyone know good resources?); Once you delve beneath the immediate surface of IOStreams, e.g. if you want to extend IOStreams with your own classes, you get to an interface with fairly cryptic and confusing member function names, e.g. getloc/imbue, uflow/underflow, snextc/sbumpc/sgetc/sgetn, pbase/pptr/epptr (and there's probably even worse examples). This makes it so much harder to understand the overall design and how the single parts co-operate. Even the book I mentioned above doesn't help that much (IMHO). Thus my question: If you had to judge by today's software engineering standards (if there actually is any general agreement on these), would C++'s IOStreams still be considered well-designed? (I wouldn't want to improve my software design skills from something that's generally considered outdated.)

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  • Colour manipulation of custom tags in niceEdit HTML editor ( JS / DOM )

    - by Chris
    Hi, I would like to be able to highlight, during typing and in real time, certain custom tags in the format #tag_name# within the text of a nicEdit instance ( http://nicedit.com/ ). My current attempt to implement as close to this as possible revolves around using the blur event of the editor to highlight the tags once the editor loses focus. I then use the following logic to wrap the tags in a span with a highlight class.. htmlEditor.addEvent( "blur", function( ) { str = nicEditors.findEditor( "html_content" ).getContent( ); // Remove existing spans first, leaving just the tag ( this could mess up if the html has been edited directly ) str = str.replace( /(<span class=\"highlight\">)(.[^<]+)(<\/span>)/gi, "$2" ); // Then wrap all instances of a particular tag with the highlight span str = str.replace( /#tag_name#/gi, "<span class='highlight'>#tag_name#</span>" ); nicEditors.findEditor( "html_content" ).setContent( str ); }); This is not ideal as my actual text now contains unwanted spans ( I only want the highlighting for the user's input experience, not to be saved to the database ). Obviously I could remove the spans before saving the text but the whole system is currently open to errors ( If the html is directly edited then other text may get highlighted etc ). What I would like to know is.. Is there any way to directly change the colour of the tags in the editor or DOM without using a mechanism such as this? Perhaps a way of colouring the text in memory rather than changing the HTML ? Any ideas ? Regards Chris P

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  • Communication between EJB3 Instances (JEE inter-bean communication) possible?

    - by Hank
    I'm designing a part of a JEE6 application, consisting of EJB3 beans. Part of the requirements are multiple parallel (say a few hundred) long running (over days) database hunts. Individual hunts have different search parameters (start time, end time, query filter). Parameters may get changed over time. Currently I'm thinking of the following: SearchController (Stateless Session Bean) formulates a set of search parameters, sends it off to a SearchListener via JMS SearchListener (Message Driven Bean) receives search parameters, instantiates a SearchWorker with the parameters SearchWorker (SLSB) hunts repeatedly through the database; when it finds something, the result is sent off via JMS, and the search continues; when the given 'end-time' has reached, it ends What I'm wondering now: Is there a problem, with EJB3 instances running for days? (Other than that I need to be able to deal with container restarts...) How do I know how many and which EJB instances of SearchWorker are currently running? Is it possible to communicate with them individually (similar to sending a System V signal to a unix process), e.g. to send new parameters, to end an instance, etc..

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  • How do I dismiss an NSPanel when creating or opening a new document?

    - by mipadi
    I am working on a document-based Cocoa application. At startup, the user is presented with a "welcome panel" (of type NSPanel) with buttons for common actions like "Create New Document" and "Open Existing Document". These actions are linked to the first responder's newDocument: and openDocument: actions, respectively, just like the matching items in the File menu. Everything works as expected...with two caveats: The welcome panel is not dismissed when creating or opening a new document. Document windows do not have focus when they are created. I have partially solved #1 by making my application controller a delegate of the welcome panel. When clicking the "Open Existing Document" button, the panel resigns its key status (since a file browser dialog is being opened), so I can close the panel in the delegate's windowDidResignKey: method. However, I can't figure out how to close the panel when creating a new document, since I can't find a notification that is posted, or a delegate method that is called, when creating a new document. And ultimately, #2 is still a problem, since the document windows don't gain focus when they're created. I have only subclassed NSDocument -- I'm not using a custom document or window controller at all. I've also tried changing the panel to an NSWindow, thinking that an NSWindow may behave differently, but the same problems are occurring.

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  • Storing multiple inputs with the same name in a CodeIgniter session

    - by Joshua Cody
    I've posted this in the CodeIgniter forum and exhausted the forum search engine as well, so apologies if cross-posting is frowned upon. Essentially, I've got a single input, set up as <input type="text" name="goal">. At a user's request, they may add another goal, which throws a duplicate to the DOM. What I need to do is grab these values in my CodeIgniter controller and store them in a session variable. My controller is currently constructed thusly: function goalsAdd(){ $meeting_title = $this->input->post('topic'); $meeting_hours = $this->input->post('hours'); $meeting_minutes = $this->input->post('minutes'); $meeting_goals = $this->input->post('goal'); $meeting_time = $meeting_hours . ":" . $meeting_minutes; $sessionData = array( 'totaltime' => $meeting_time, 'title' => $meeting_title, 'goals' => $meeting_goals ); $this->session->set_userdata($sessionData); $this->load->view('test', $sessionData); } Currently, obviously, my controller gets the value of each input, writing over previous values in its wake, leaving only a string of the final value. I need to store these, however, so I can print them on a subsequent page. What I imagine I'd love to do is extend the input class to be able to call $this-input-posts('goal'). Eventually I will need to store other arrays to session values. But I'm totally open to implementation suggestion. Thanks so much for any help you can give.

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  • Read HTML file into email

    - by cast01
    Ive written a script to send html emails and all works well. I have the email stored in a separate HTML file which is then read in usin a while loop and fgets(). However, i want to be able to pass variables into the html. For example, in a html file i may have something like.. <body> Dear Name <br/> Thank you for your recent purhcase </body> and i read this into a string like so $file = fopen($filename, "r"); while(!feof($file)) { $html.= fgets($file, 4096); } fclose ($file); I want to be able to replace "Name" in the html file by a variable and im not entirely sure on the best way to do this. I could always make my own tag and then use regex to replace that with the name once ive read the file into the string, but im wondering if there is a better/easier method to do this. (On a side note, if anyone knows whether its better to use file_get_contents instead of multiple calls to fgets, id be interested to know)

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  • Issue on maven 2.2.1

    - by Dawit
    I wrote a small maven plugin and everything seems to work well with prior version of maven (2.0.9) but my build fails on version 2.2.1 The stack trace does not show anything from my end of the code and was wondering if anyone has encountered this issue. .... .... [ERROR] FATAL ERROR [INFO] ------------------------------------------------------------------------ [INFO] null [INFO] ------------------------------------------------------------------------ [INFO] Trace java.lang.NullPointerException at java.util.Hashtable.put(Hashtable.java:396) at java.util.Properties.setProperty(Properties.java:128) at org.apache.maven.project.ModelUtils.cloneProperties(ModelUtils.java:1264) at org.apache.maven.project.ModelUtils.cloneModelBaseFields(ModelUtils.java:318) at org.apache.maven.project.ModelUtils.cloneModel(ModelUtils.java:953) at org.apache.maven.project.DefaultMavenProjectBuilder.calculateConcreteStateInternal(DefaultMavenProjectBuilder.java:1855) at org.apache.maven.project.DefaultMavenProjectBuilder.calculateConcreteState(DefaultMavenProjectBuilder.java:1814) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.calculateConcreteState(DefaultLifecycleExecutor.java:779) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:575) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalWithLifecycle(DefaultLifecycleExecutor.java:540) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:519) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:371) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:332) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:181) at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:356) at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:137) at org.apache.maven.cli.MavenCli.main(MavenCli.java:362) at org.apache.maven.cli.compat.CompatibleMain.main(CompatibleMain.java:41) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:592) at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315) at org.codehaus.classworlds.Launcher.launch(Launcher.java:255) at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430) at org.codehaus.classworlds.Launcher.main(Launcher.java:375) [INFO] ------------------------------------------------------------------------ [INFO] Total time: 17 seconds [INFO] Finished at: Thu May 27 16:18:40 CDT 2010 [INFO] Final Memory: 35M/63M

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  • How to detect whether there is a specific member variable in class?

    - by Kirill V. Lyadvinsky
    For creating algorithm template function I need to know whether x or X (and y or Y) in class that is template argument. It may by useful when using my function for MFC CPoint class or GDI+ PointF class or some others. All of them use different x in them. My solution could be reduces to the following code: template<int> struct TT {typedef int type;}; template<class P> bool Check_x(P p, typename TT<sizeof(&P::x)>::type b = 0) { return true; } template<class P> bool Check_x(P p, typename TT<sizeof(&P::X)>::type b = 0) { return false; } struct P1 {int x; }; struct P2 {float X; }; // it also could be struct P3 {unknown_type X; }; int main() { P1 p1 = {1}; P2 p2 = {1}; Check_x(p1); // must return true Check_x(p2); // must return false return 0; } But it does not compile in Visual Studio, while compiling in the GNU C++. With Visual Studio I could use the following template: template<class P> bool Check_x(P p, typename TT<&P::x==&P::x>::type b = 0) { return true; } template<class P> bool Check_x(P p, typename TT<&P::X==&P::X>::type b = 0) { return false; } But it does not compile in GNU C++. Is there universal solution? UPD: Structures P1 and P2 here are only for example. There are could be any classes with unknown members.

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  • rewrite not a member of LiftRules

    - by José Leal
    Hi guys, I was following http://www.assembla.com/wiki/show/liftweb/URL_Rewriting tutorial for url rewritting in liftweb.. but I get this error: error: value rewrite is not a member of object net.liftweb.http.LiftRules .. it is really odd.. and the documentation says that it exists. I'm using idea IDE, and I've done everything from scratch, using the lift maven blank archifact. Some more info: [INFO] ------------------------------------------------------------------------ [INFO] Building Joseph3 [INFO] task-segment: [tomcat:run] [INFO] ------------------------------------------------------------------------ [INFO] Preparing tomcat:run [INFO] [resources:resources {execution: default-resources}] [WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 0 resource [INFO] [yuicompressor:compress {execution: default}] [INFO] nb warnings: 0, nb errors: 0 [INFO] artifact org.mortbay.jetty:jetty: checking for updates from scala-tools.org [INFO] artifact org.mortbay.jetty:jetty: checking for updates from central [INFO] [compiler:compile {execution: default-compile}] [INFO] Nothing to compile - all classes are up to date [INFO] [scala:compile {execution: default}] [INFO] Checking for multiple versions of scala [INFO] /home/dpz/Scala/Doit/Joseph3/src/main/scala:-1: info: compiling [INFO] Compiling 2 source files to /home/dpz/Scala/Doit/Joseph3/target/classes at 1274922123910 [ERROR] /home/dpz/Scala/Doit/Joseph3/src/main/scala/bootstrap/liftweb/Boot.scala:16: error: value rewrite is not a member of object net.liftweb.http.LiftRules [INFO] LiftRules.rewrite.prepend(NamedPF("ProductExampleRewrite") { [INFO] ^ [ERROR] one error found [INFO] ------------------------------------------------------------------------ [ERROR] BUILD ERROR [INFO] ------------------------------------------------------------------------ [INFO] wrap: org.apache.commons.exec.ExecuteException: Process exited with an error: 1(Exit value: 1) [INFO] ------------------------------------------------------------------------ [INFO] For more information, run Maven with the -e switch [INFO] ------------------------------------------------------------------------ [INFO] Total time: 19 seconds [INFO] Finished at: Thu May 27 03:02:07 CEST 2010 [INFO] Final Memory: 20M/175M [INFO] ------------------------------------------------------------------------ Process finished with exit code 1 enter code here

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  • Is Software Engineering Dead? [closed]

    - by nik
    Right from Jeff's blog: Software Engineering: Dead? I was utterly floored when I read this new IEEE article by Tom DeMarco (pdf). See if you can tell why. He quotes DeMarco, "I'm gradually coming to the conclusion that software engineering is an idea whose time has come and gone". Further, "What DeMarco seems to be saying -- and, at least, what I am definitely saying -- is that control is ultimately illusory on software development projects." I am writing these lines without context to invoke reading of the related subject. What are the views of the programming community here? I have started to realize that a community wiki is not getting the right amount of participation here. That is the reason I left this question out in the open, while still contemplating a change to CW. It was closed once, and I thought that was the end of it. But, now I see it was reopened and has more answers (all of which I have not yet read). However, I see a lot of CW requests and am forced to reconsider that. This is how I intend to make the CW decision here. There is a comment by Neil Butterworth requesting a CW at 12 upvotes -- "should be community wiki" There is a comment by Lance Roberts requesting no CW at 0 upvotes -- "+1 for not putting it in community wiki" The difference is 12 for a CW request at the moment If this difference becomes 5 more (that is 17), I'll move this question to CW, and it will not return back from there Of course, there is also a close vote at the moment; the question may be closed again.

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  • What is the best way to iterate over a large result set in JDBC/iBatis 3?

    - by paul_sns
    We're trying to iterate over a large number of rows from the database and convert those into objects. Behavior will be as follows: Result will be sorted by sequence id, a new object will be created when sequence id changes. The object created will be sent to an external service and will sometimes have to wait before sending another one (which means the next set of data will not be immediately used) We already have invested code in iBatis 3 so an iBatis solution will be the best approach for us (we've tried using RowBounds but haven't seen how it does the iteration under the hood). We'd like to balance minimizing memory usage and reducing number of DB trips. We're also open to pure JDBC approach but we'd like the solution to work on different databases. UPDATE: We need to make as few calls to DB as possible (1 call would be the ideal scenario) while also preventing the application to use too much memory. Are there any other solutions out there for this type of problem may it be pure JDBC or any other technology? Thanks and hope to hear your insights on this.

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  • VB.net httpwebrequest For loop hangs every 10 or so iterations

    - by user574632
    Hello, I am trying to loop through an array and perform an httpwebrequest in each iteration. The code seems to work, however it pauses for a while (eg alot longer than the set timeout. Tried setting that to 100 to check and it still pauses) after every 10 or so iterations, then carries on working. Here is what i have so far: For i As Integer = 0 To numberOfProxies - 1 Try 'create request to a proxyJudge php page using proxy Dim request As HttpWebRequest = HttpWebRequest.Create("http://www.pr0.net/deny/azenv.php") request.Proxy = New Net.WebProxy(proxies(i)) 'select the current proxie from the proxies array request.Timeout = 10000 'set timeout Dim response As HttpWebResponse = request.GetResponse() Dim sr As StreamReader = New StreamReader(response.GetResponseStream()) Dim pageSourceCode As String = sr.ReadToEnd() 'check the downloaded source for certain phrases, each identifies a type of proxy 'HTTP_X_FORWARDED_FOR identifies a transparent proxy If pageSourceCode.Contains("HTTP_X_FORWARDED_FOR") Then 'delegate method for cross thread safe UpdateListbox(ListBox3, proxies(i)) ElseIf pageSourceCode.Contains("HTTP_VIA") Then UpdateListbox(ListBox2, proxies(i)) Else UpdateListbox(ListBox1, proxies(i)) End If Catch ex As Exception 'MessageBox.Show(ex.ToString) used in testing UpdateListbox(ListBox4, proxies(i)) End Try completedProxyCheck += 1 lblTotalProxiesChecked.CustomInvoke(Sub(l) l.Text = completedProxyCheck) Next I have searched all over this site and via google, and most responses to this type of question say the response must be closed. I have tried a using block, eg: Using response As HttpWebResponse = request.GetResponse() Using sr As StreamReader = New StreamReader(response.GetResponseStream()) Dim pageSourceCode As String = sr.ReadToEnd() 'check the downloaded source for certain phrases, each identifies a type of proxy 'HTTP_X_FORWARDED_FOR identifies a transparent proxy If pageSourceCode.Contains("HTTP_X_FORWARDED_FOR") Then 'delegate method for cross thread safe UpdateListbox(ListBox3, proxies(i)) ElseIf pageSourceCode.Contains("HTTP_VIA") Then UpdateListbox(ListBox2, proxies(i)) Else UpdateListbox(ListBox1, proxies(i)) End If End Using End Using And it makes no difference (though i may have implemented it wrong) As you can tell im very new to VB or any OOP so its probably a simple problem but i cant work it out. Any suggestions or just tips on how to diagnose these types of problems would be really appreciated.

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  • How should I avoid memoization causing bugs in Ruby?

    - by Andrew Grimm
    Is there a consensus on how to avoid memoization causing bugs due to mutable state? In this example, a cached result had its state mutated, and therefore gave the wrong result the second time it was called. class Greeter def initialize @greeting_cache = {} end def expensive_greeting_calculation(formality) case formality when :casual then "Hi" when :formal then "Hello" end end def greeting(formality) unless @greeting_cache.has_key?(formality) @greeting_cache[formality] = expensive_greeting_calculation(formality) end @greeting_cache[formality] end end def memoization_mutator greeter = Greeter.new first_person = "Bob" # Mildly contrived in this case, # but you could encounter this in more complex scenarios puts(greeter.greeting(:casual) << " " << first_person) # => Hi Bob second_person = "Sue" puts(greeter.greeting(:casual) << " " << second_person) # => Hi Bob Sue end memoization_mutator Approaches I can see to avoid this are: greeting could return a dup or clone of @greeting_cache[formality] greeting could freeze the result of @greeting_cache[formality]. That'd cause an exception to be raised when memoization_mutator appends strings to it. Check all code that uses the result of greeting to ensure none of it does any mutating of the string. Is there a consensus on the best approach? Is the only disadvantage of doing (1) or (2) decreased performance? (I also suspect freezing an object may not work fully if it has references to other objects) Side note: this problem doesn't affect the main application of memoization: as Fixnums are immutable, calculating Fibonacci sequences doesn't have problems with mutable state. :)

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  • rails semi-complex STI with ancestry data model planning the routes and controllers

    - by ere
    I'm trying to figure out the best way to manage my controller(s) and models for a particular use case. I'm building a review system where a User may build a review of several distinct types with a Polymorphic Reviewable. Country (has_many reviews & cities) Subdivision/State (optional, sometimes it doesnt exist, also reviewable, has_many cities) City (has places & review) Burrow (optional, also reviewable ex: Brooklyn) Neighborhood (optional & reviewable, ex: williamsburg) Place (belongs to city) I'm also wondering about adding more complexity. I also want to include subdivisions occasionally... ie for the US, I might add Texas or for Germany, Baveria and have it be reviewable as well but not every country has regions and even those that do might never be reviewed. So it's not at all strict. I would like it to as simple and flexible as possible. It'd kinda be nice if the user could just land on one form and select either a city or a country, and then drill down using data from say Foursquare to find a particular place in a city and make a review. I'm really not sure which route I should take? For example, what happens if I have a Country, and a City... and then I decide to add a Burrow? Could I give places tags (ie Williamsburg, Brooklyn) belong_to NY City and the tags belong to NY? Tags are more flexible and optionally explain what areas they might be in, the tags belong to a city, but also have places and be reviewable? So I'm looking for suggestions for anyone who's done something related. Using Rails 3.2, and mongoid.

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  • curios about CCSpriteBatchNode's addchild method

    - by lzyy
    when diving into "learn cocos2d game development with ios5", in ch08 in EnemyCache.m -(id) init { if ((self = [super init])) { // get any image from the Texture Atlas we're using CCSpriteFrame* frame = [[CCSpriteFrameCache sharedSpriteFrameCache] spriteFrameByName:@"monster-a.png"]; batch = [CCSpriteBatchNode batchNodeWithTexture:frame.texture]; [self addChild:batch]; [self initEnemies]; [self scheduleUpdate]; } return self; } so batch is with texture "monster-a.png" in EnemyEntity.m's initWithType method switch (type) { case EnemyTypeUFO: enemyFrameName = @"monster-a.png"; bulletFrameName = @"shot-a.png"; break; case EnemyTypeCruiser: enemyFrameName = @"monster-b.png"; bulletFrameName = @"shot-b.png"; shootFrequency = 1.0f; initialHitPoints = 3; break; case EnemyTypeBoss: enemyFrameName = @"monster-c.png"; bulletFrameName = @"shot-c.png"; shootFrequency = 2.0f; initialHitPoints = 15; break; default: [NSException exceptionWithName:@"EnemyEntity Exception" reason:@"unhandled enemy type" userInfo:nil]; } if ((self = [super initWithSpriteFrameName:enemyFrameName])) { //... } so the returned object may be in 3 different frame. since Only the CCSprites that are contained in that texture can be added to the CCSpriteBatchNode, obviously, 'monster-b.png' is not contained in 'monster-a.png', why the different enemy can still be added to the batch?

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  • How/when to hire new programmers, and how to integrate them?

    - by Shaul
    Hiring new programmers, especially in a small company, can often present a Catch-22 situation. We have too much work to do, so we need to hire new programmers. But we can't hire new programmers now, because they will need mentoring and several months of learning curve in your industry/product/environment before they're useful, and none of the programmers has time to be a mentor to a new programmer, because they're all completely swamped with the current work load. That may be a slightly frivolous way of describing the situation, but nevertheless, it's difficult for a small company on a tight budget to justify hiring someone who is not only going to be unproductive for a long time, but will also take away from the performance of the current programmers. How have you dealt with this kind of situation? When is the best time to hire someone? What are the best tasks to assign to a new team member so that they can learn their way around your code base and start getting their hands dirty as quickly as possible? How do you get the new guy useful without bogging your existing programmers down in too much mentoring? Any comments & suggestions you have are much appreciated!

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  • Binding a list belonging to another object in a custom model binder in ASP.NET MVC

    - by Dan
    I realize something like this has been asked, but this may be a little different Below is my Event object: Event : IEvent public int Id public string Title public List<EventContact> Contacts And EventContact: EventContact public int Id public string Name So, an Event has a list of EventContact' objects. Now, Event also implements IEvent - hence the custom model binder. I useIEventinstead of Event, so when the default model binder tries to do its thing, it lets me know it can't create anIEvent'. I have my view with populated with the contact info: <input type="text" name="contact[0].Name" value="DB Value"/> <input type="text" name="contact[1].Name" value="DB Value"/> <input type="text" name="contact[2].Name" value="DB Value"/> <!-- Event fields, etc --> So, in my custom model binder I am able to see all the value - sweet! The only thing is, I'm really not sure how to get all the contact fields and create a list of contacts from them, along with binding all the Event fields. Any and all help is appreciated!

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