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  • What's the most efficient way to load data from a file to a collection on-demand?

    - by Dan
    I'm working on a java project that will allows users to parse multiple files with potentially thousands of lines. The information parsed will be stored in different objects, which then will be added to a collection. Since the GUI won't require to load ALL these objects at once and keep them in memory, I'm looking for an efficient way to load/unload data from files, so that data is only loaded into the collection when a user requests it. I'm just evaluation options right now. I've also thought of the case where, after loading a subset of the data into the collection, and presenting it on the GUI, the best way to reload the previously observed data. Re-run the parser/Populate collection/Populate GUI? or probably find a way to keep the collection into memory, or serialize/deserialize the collection itself? I know that loading/unloading subsets of data can get tricky if some sort of data filtering is performed. Let's say that I filter on ID, so my new subset will contain data from two previous analyzed subsets. This would be no problem is I keep a master copy of the whole data in memory. I've read that google-collections are good and efficient when handling big amounts of data, and offer methods that simplify lots of things so this might offer an alternative to allow me to keep the collection in memory. This is just general talking. The question on what collection to use is a separate and complex thing. Do you know what's the general recommendation on this type of task? I'd like to hear what you've done with similar scenarios. I can provide more specifics if needed.

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  • parsing urls from windows batch file

    - by modest
    I have a text file (myurls.txt) whose contents are a list of URLs as follow: Slides_1: http://linux.koolsolutions.com/svn/ProjectA/tags/REL-1.0 Exercise_1: http://linux.koolsolutions.com/svn/ProjectA/tags/REL-1.0 Slides_2: http://linux.koolsolutions.com/svn/oldproject/ProjectB/tags/REL-2.0 Exercise_2: http://linux.koolsolutions.com/svn/ProjectB/tags/REL-1.0 Exercise_3: http://linux.koolsolutions.com/svn/BlueBook/ProjectA/tags/REL-1.0 Now I want to parse this text file in a for loop such that after each iteration (for e.g. take the first url from the above file) I have the following information into different variables: %i% = REL-1.0 %j% = http://linux.koolsolutions.com/svn/ProjectA %k% = http://linux.koolsolutions.com/svn/ProjectA/tags/REL-1.0 After some experiment I have the following code but it only works (kind of) if the URLs have same number of slashes: @echo off set FILE=myurls.txt FOR /F "tokens=2-9 delims=/ " %%i in (%FILE%) do ( @REM <do something with variables i, j and k.> ) I am fine with other solutions like for e.g. using Windows Script Host/VBS script as long as it can run with a default Windows XP/7 installation. In other words, I know I can use awk, grep, sed, python, etc. for Windows and get the job done but I don't want the users to have to install anything besides a standard windows installation.

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  • UserControl/TreeView Problem....Not getting result during runtime..

    - by Samiul
    Hi all, My problem is, I'm using a TreeView in a UserControl. While debugging, I can see the results are adding in the TreeView but it's not happening when I'm using that UserControl onto my MainForm. The UserControl containing the TreeView remains blank during runtime of the main application. I've also referenced the UserControl project with my Main project. Here I'm giving my code for helping me out. Thanks in advance. Code: In the UserControl class: public override void Refresh() { PopulateTreeView(); } private void PopulateTreeView() { TreeNodeCollection treeNodeCollection; treeNodeCollection = CreateParentNode("My Information"); CreateChildNode(treeNodeCollection, "Name"); CreateChildNode(treeNodeCollection, "Address"); this.Update(); myTreeView.ExpandAll(); } private TreeNodeCollection CreateParentNode(string parentNode) { TreeNode treeNode = new TreeNode(parentNode); myTreeView.Nodes.Add(treeNode); return treeNode.Nodes; } private void CreateChildNode(TreeNodeCollection nodeCollection, string itemName) { TreeNode treeNode = new TreeNode(itemName); nodeCollection.Add(treeNode); } In my MainForm: private void button1_Click(object sender, EventArgs e) { UserControl userControl = new UserControl(); userControl.Refresh(); }

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  • JavaScript change to DropDownList.SelectedIndex not submitted

    - by Bellfalasch
    Hi So, I have a form to submit fighters. You write his/her name, country, and then the team they fight for + the team's country. When you start typing the name I have constructed my own Ajax AutoCompleter. It will find existing fighters that might match. When you click on one of the suggestions it will populate up to four fields depending on existing data in the database. If you're lucky the fighter already exists with information on country, team, and the team's country. The problems starts when submitting. The JavaScript follows and just get's the id of the country to select (also the value of the select-option), and the select-element itself. function dropdownSelect(value, element) { var dropdown = document.getElementById(element); for (var i = 0; i < dropdown.options.length; i++) { if (dropdown.options[i].value == value) { dropdown.options[i].selected = true; return true; } } } When submitting the ASP.NET-code halt's and says that my country-field is null. So my JavaScript-change of selected field couldn't be read by ASP.NET. Is this a limitation of how ASP.NET works? Or a limitation of my skills? ;P

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  • PHP Notice: Undefined index when looping array...

    - by Jonathan
    Hi, I'm looping a two-dimensional array like this: if (!empty($aka)) { foreach ($aka as $ak) { if($ak["lang"]=="es") { $sptitle=$ak["title"]; } } } Pretty simple. If the array ($aka) is not empty I loop trough it and when it finds that the "lang" index is equal to "es" I just save the "title" value for that index in $sptitle. The problem is that the array ($aka) contains a lot of information and sometimes there is no "lang" index... and I get this error: Notice: Undefined index: lang. How can I fix this??? This is a extract of the array to help you understand. Notice that [1] doesn't have a [lang] index but [2] does have: [1] =&gt; Array ( [title] =&gt; The Lord of the Rings: The Motion Picture [year] =&gt; [country] =&gt; USA [comment] =&gt; promotional title ) [2] =&gt; Array ( [title] =&gt; Señor de los anillos: La comunidad del anillo, El [year] =&gt; [country] =&gt; Argentina [comment] =&gt; Chile, Mexico, Peru, Spain [lang] =&gt; es ) Thanks!

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  • Creating Binary Block from struct

    - by MOnsDaR
    I hope the title is describing the problem, i'll change it if anyone has a better idea. I'm storing information in a struct like this: struct AnyStruct { AnyStruct : testInt(20), testDouble(100.01), testBool1(true), testBool2(false), testBool3(true), testChar('x') {} int testInt; double testDouble; bool testBool1; bool testBool2; bool testBool3; char testChar; std::vector<char> getBinaryBlock() { //how to build that? } } The struct should be sent via network in a binary byte-buffer with the following structure: Bit 00- 31: testInt Bit 32- 61: testDouble most significant portion Bit 62- 93: testDouble least significant portion Bit 94: testBool1 Bit 95: testBool2 Bit 96: testBool3 Bit 97-104: testChar According to this definition the resulting std::vector should have a size of 13 bytes (char == byte) My question now is how I can form such a packet out of the different datatypes I've got. I've already read through a lot of pages and found datatypes like std::bitset or boost::dynamic_bitset, but neither seems to solve my problem. I think it is easy to see, that the above code is just an example, the original standard is far more complex and contains more different datatypes. Solving the above example should solve my problems with the complex structures too i think. One last point: The problem should be solved just by using standard, portable language-features of C++ like STL or Boost (

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  • iPhone: Low memory crash...

    - by MacTouch
    Once again I'm hunting memory leaks and other crazy mistakes in my code. :) I have a cache with frequently used files (images, data records etc. with a TTL of about one week and a size limited cache (100MB)). There are sometimes more then 15000 files in a directory. On application exit the cache writes an control file with the current cache size along with other useful information. If the applications crashes for some reason (sh.. happens sometimes) I have in such case to calculate the size of all files on application start to make sure I know the cache size. My app crashes at this point because of low memory and I have no clue why. Memory leak detector does not show any leaks at all. I do not see any too. What's wrong with the code below? Is there any other fast way to calculate the total size of all files within a directory on iPhone? Maybe without to enumerate the whole contents of the directory? The code is executed on the main thread. NSUInteger result = 0; NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSDirectoryEnumerator *dirEnum = [[[NSFileManager defaultManager] enumeratorAtPath:path] retain]; int i = 0; while ([dirEnum nextObject]) { NSDictionary *attributes = [dirEnum fileAttributes]; NSNumber* fileSize = [attributes objectForKey:NSFileSize]; result += [fileSize unsignedIntValue]; if (++i % 500 == 0) { // I tried lower values too [pool drain]; } } [dirEnum release]; dirEnum = nil; [pool release]; pool = nil; Thanks, MacTouch

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  • Some images fails to load on Windows Server 2008

    - by Guffa
    I have an application running on a Windows Server 2008, that is processing uploaded images. Currently it successfully processes about 8000 images per day, creating 11 different sizes of each image. The problem that I have is that sometimes the application fails to load some images, I get the error "System.Runtime.InteropServices.ExternalException: A generic error occurred in GDI+.". The upload only accepts files with a JPEG extension (jpg/jpeg/jpe) or with a JPEG MIME type, and from what I can tell those images are really JPEG images. If I look at the image file in windows explorer on the server, it can successfully extract the thumbnail from the file, but if I try to open it, I get the error message "This is not a valid bitmap file, or it's format is not currently supported." from Paint. If I copy the image to my own computer, running Windows 7, there is no problem opening the image. It works in Paint, Windows Photo Viewer, Adobe Bridge, and Photoshop. If I try to load the image using Image.FromStream the same way as in the application running on the server, it loads just fine. (I have copied the file back to the server, and it still doesn't work, so there is nothing in the copying process that changes it.) When I look at the image information in Bridge, I see that the images are created using Picasa 3.0, but other than that I can't see anything special about them. I haven't yet found anyone having the same problem, or any known problems like this with the Picasa application. Has anyone had any similar problem, or know if there is something special about images created using Picasa? Is there any image codec that needs installing on the server to handle all kinds of JPEG images?

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  • Dynamic editor upload into web page. Need advice

    - by Andrew Florko
    Hello everybody, I am writing intranet site for tracking employees science activities in organization. There lots of editable information on each personal page (science degree, publications & so on) so I upload editor per request (user clicks "edit" and modal dialog with html editor: set of textboxes/comboboxes/autocomplete features & validation logic appears). Editor is html layout that is wrapped with jquery dialog plugin + some logic, written as javascript functions that should be invoked from the callee page (onsubmit, validate, afterLoad editor events). There are also attributes (editor preferrable with and height) that are passed to callee page also. Currently I send these functions & attribute as ... function onsubmit() { }; function validate() { } var width = 640; var height = 800 ... code that is embedded into the request page. Function calls and editor markup wrap with jquery plugin completed in the callee page. It works, but I have some try { call editor event handler } catch { } stuff in callee page (because not every editor provides these functions) and some attributes (editor width & height for instance) that are loaded as variables declared in javascript. Please, suggest, is there a better approach to build & use custom editors for my situation. Thank you in advance!

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  • MySql "comments" parameter as descriptor?

    - by Nick
    So, I'm trying to learn a lot at once, and this place is really helpful! I'm making a little running log website for myself and maybe a few other people, and I have it so that the user can add workouts for each day. With each workout, I have a variety of information the user can fill out for the workout, such as running distance, time, quality of run, course, etc... I store this in a MySql database as a table with fields titled "distance", "time", "runquality", etc... Now, these field titles don't match up with what I want displayed on the running log, so I was thinking of using the "Comments" attribute for a field to store its human-readable title--thus the field "runquality" would have "Quality of run" as its comment, and then I would pull the comment with a SQL query and display it instead of the field name. Is this a good theoretical/practical way of going about it? And what sort of SQL would I use to pull the comment for the field anyway? Secondly, suppose I want to add the ability for the user to create their own workout descriptors. So say a user wants to add a "temperature" descriptor for their workout. Should I create a script that adds fields to my workout table, or should I create a separate table listing only workout descriptors and somehow link the descriptor table with the "contents" table? I haven't learned any theory about database design or anything so any help is appreciated!

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  • Any suggestions to improve my PDO connection class?

    - by Scarface
    Hey guys I am pretty new to pdo so I basically just put together a simple connection class using information out of the introductory book I was reading but is this connection efficient? If anyone has any informative suggestions, I would really appreciate it. class PDOConnectionFactory{ public $con = null; // swich database? public $dbType = "mysql"; // connection parameters public $host = "localhost"; public $user = "user"; public $senha = "password"; public $db = "database"; public $persistent = false; // new PDOConnectionFactory( true ) <--- persistent connection // new PDOConnectionFactory() <--- no persistent connection public function PDOConnectionFactory( $persistent=false ){ // it verifies the persistence of the connection if( $persistent != false){ $this->persistent = true; } } public function getConnection(){ try{ $this->con = new PDO($this->dbType.":host=".$this->host.";dbname=".$this->db, $this->user, $this->senha, array( PDO::ATTR_PERSISTENT => $this->persistent ) ); // carried through successfully, it returns connected return $this->con; // in case that an error occurs, it returns the error; }catch ( PDOException $ex ){ echo "We are currently experiencing technical difficulties. We have a bunch of monkies working really hard to fix the problem. Check back soon: ".$ex->getMessage(); } } // close connection public function Close(){ if( $this->con != null ) $this->con = null; } }

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  • webBrower Button Click without element ID?

    - by Jeremy
    I'm working on a login system for a forum and trying to make it work via a c# .net form. I need to programitically click the login button on the forum with a webBrower control. So far I have this. webPage page = new webPage(); page.URL = txtURL.Text; page.Load(); //Load the text from the specified URL WebBrowser browser = new WebBrowser(); browser.Document.GetElementById("navbar_username").SetAttribute("value", textBox1.Text); browser.Document.GetElementById("navbar_password").SetAttribute("value", textBox2.Text); HtmlElement el = browser.Document.All["btnI"]; if (el != null) { el.InvokeMember("click"); } else { MessageBox.Show("There is an issue with the program"); } The issue is that the login button on the page does not have an ID or any real information that can allow me to click on it. Does anyone have any suggestions? Here is the code for the login button. <input type="image" src="images/loginbutton.png" class="loginbutton" tabindex="104" value="Log in" title="Enter your username and password in the boxes provided to login, or click the 'register' button to create a profile for yourself." accesskey="s">

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  • Sharepoint alerts not working when multiple people are in an item

    - by csm8118
    We use Sharepoint Services 3.0 as a project tracking tool. We have a list set up that contains your basic information (description, etc.) plus we have a "assigned person" column that is of type Person or Group that we use to associate list items with individuals. This column supports multiple selections. We would like to set up alerts such that each person gets an alert email only if they are assigned to a list item. The approach we have taken is to set up a view on this list that is filtered to show list items where the assigned person equals [Me], and then to create an alert on this list that is set to send an email when someone changes an items that appears in the view. This works well when there is only one person in the assigned person column. It does not work when there is more than one person in the assigned person column. Does anybody know why this wouldn't work, or what I can do to troubleshoot? Is there a better way to achieve the end result? We could make several "assigned person" columns and not allow multiple selections, but that seems kind of kludgy.

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  • The youtube API sometimes throws error: Call to a member function children() on a non-object

    - by Anna Lica
    When i launch the php script, sometime works fine, but many other times it retrieve me this errror Fatal error: Call to a member function children() on a non-object in /membri/americanhorizon/ytvideo/rilevametadatadaurlyoutube.php on line 21 This is the first part of the code // set feed URL $feedURL = 'http://gdata.youtube.com/feeds/api/videos/dZec2Lbr_r8'; // read feed into SimpleXML object $entry = simplexml_load_file($feedURL); $video = parseVideoEntry($entry); function parseVideoEntry($entry) { $obj= new stdClass; // get nodes in media: namespace for media information $media = $entry->children('http://search.yahoo.com/mrss/'); //<----this is the doomed line 21 UPDATE: solution adopted for ($i=0 ; $i< count($fileArray); $i++) { // set feed URL $feedURL = 'http://gdata.youtube.com/feeds/api/videos/'.$fileArray[$i]; // read feed into SimpleXML object $entry = simplexml_load_file($feedURL); if ( is_object($entry)) { $video = parseVideoEntry($entry); echo ($video->description."|".$video->length); echo "<br>"; } else { $i--; } } In this mode i force the script to re-check the file that caused the error

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  • Send file FTP over SSL with custom port number

    - by JM4
    I have asked the question before but in a different manner. I am trying taking form data, compiling into a temporary CSV file and trying to send over to a client via FTP over SSL (this is the only route I am interested in hearing solutions for unless there is a workaround to doing this, I cannot make changes). I have tried the following: ftp_connect - nothing happens, the page just times out ftp_ssl_connect - nothing happens, the page just times out curl library - same thing, given URL it also gives error. I am given the following information: FTPS Server IP Address TCP Port (1234) Username Password Data Directory to dump file FTP Mode: Passive very, very basic code (which I believe should initiate a connection at minimum): Code: <?php $ftp_server = "00.000.00.000"; //masked for security $ftp_port = "1234"; // masked but not 990 $ftp_user_name = "username"; $ftp_user_pass = "password"; // set up basic ssl connection $conn_id = ftp_ssl_connect($ftp_server, $ftp_port, "20"); // login with username and password $login_result = ftp_login($conn_id, $ftp_user_name, $ftp_user_pass); echo ftp_pwd($conn_id); // / echo "hello"; // close the ssl connection ftp_close($conn_id); ?> When I run this over a SmartFTP client, everything works just fine. I just can't get it to work using PHP (which is a necessity). Has anybody had success doing this in the past? I would be very interested to hear your approach.

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  • Understanding REST: is GET fundamentally incompatible with any "number of views" counter?

    - by cocotwo
    I'm trying to understand REST. Under REST a GET must not trigger something transactional on the server (this is a definition everybody agrees upon, it is fundamental to REST). So imagine you've got a website like stackoverflow.com (I say like so if I got the underlying details of SO wrong it doesn't change anything to my question), where everytime someone reads a question, using a GET, there's also some display showing "This question has been read 256 times". Now someone else reads that question. The counter now is at 257. The GET is transactional because the number of views got incremented and is now incremented again. The "number of views" is incremented in the DB, there's no arguing about that (for example on SO the number of time any question has been viewed is always displayed). So, is a REST GET fundamentally incompatible with any kind of "number of views" like functionality in a website? So should it want to be "RESTFUL", should the SO main page either stop display plain HTML links that are accessed using GETs or stop displaying the "this question has been viewed x times"? Because incrementing a counter in a DB is transactional and hence "unrestful"? EDIT just so that people Googling this can get some pointers: From http://www.xfront.com/REST-Web-Services.html : 4. All resources accessible via HTTP GET should be side-effect free. That is, the request should just return a representation of the resource. Invoking the resource should not result in modifying the resource. Now to me if the representation contains the "number of views", it is part of the resource [and in SO the "number of views" a question has is a very important information] and accessing it definitely modifies the resource. This is in sharp contrast with, say, a true RESTFUL HTTP GET like the one you can make on an Amazon S3 resource, where your GET is guaranteed not to modify the resource you get back. But then I'm still very confused.

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  • Angularjs throws TypeError: Cannot read property 'indexOf' of undefined

    - by Ali
    I'm trying to debug the above code which I feel like this is very useful .< I can't even find what is wrong in my code and don't really know where to start since Angularjs still very new to me. I'm trying to localize Angularjs app. I know this is missing a lot of context in order to get a help, but I'm trying to see what information that I should give that would help on this debugging. I've gone through any indexOf in angularjs file and I can see few things is undefined but don't know if that would be helpful. So I've traced the problem here and this is what I have figured is the problem, but still counldn't figure out why... config(['$routeProvider', '$locationProvider', function ($routeProvider, $locationProvider) { $routeProvider.when('/:locale?/:username/badges', { templateUrl: '_partials/badges.html', controller: 'badges' }) .when('/:username/badges', { templateUrl: '_partials/badges.html', controller: 'badges' }) .when('/:username/teaching-resources', { templateUrl: '_partials/teaching-resources.html', controller: 'teachingResources' }) .when('/:username/makes', { templateUrl: '_partials/makes.html', controller: 'makes' }) .when('/:username/likes', { templateUrl: '_partials/likes.html', controller: 'likes' }) .when('/:username/events', { templateUrl: '_partials/events.html', controller: 'events' }) .when('/:username', { templateUrl: '_partials/badges.html', controller: 'badges' }); $routeProvider.otherwise({ redirectTo: '/error/404' }); The URL that I'm visiting for default page is: This will fail and throw the error. http://localhost:1969/en-US/user/someUserName This will work fine http://localhost:1969/user/someUserName UPDATE I figured out! This is the problem: $locationProvider.html5Mode(true); But why!?

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  • Working with fields which can mutate or be new instances altogether

    - by dotnetdev
    Structs are usually used for immutable data, eg a phone number, which does not mutate, but instead you get a new one (eg the number 000 becoming 0001 would mean two seperate numbers). However, pieces of information like Name, a string, can either mutate (company abc changing its name to abcdef, or being given a new name like def). For fields like this, I assume they should reside in the mutable class and not an immutable structure? My way of structuring code is to have an immutable concept, like Address (any change is a new address completely), in a struct and then reference it from a class like Customer, since Customer always has an address. So I would put CompanyName, or Employer, in the class as it is mutable. But a name can either mutate and so be the same 1 instance, or a new name setup and while the company still owning the first name too. Would the correct pattern for assigning a new instance (eg a new company name but the old name still owned by the company) be?: string name = ""; string newName = new string(); newName = "new"; name = newName; And a mutation just the standard assignment pattern? Thanks

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  • Atomic operations on several transactionless external systems

    - by simendsjo
    Say you have an application connecting 3 different external systems. You need to update something in all 3. In case of a failure, you need to roll back the operations. This is not a hard thing to implement, but say operation 3 fails, and when rolling back, the rollback for operation 1 fails! Now the first external system is in an invalid state... I'm thinking a possible solution is to shut down the application and forcing a manual fix of the external system, but then again... It might already have used this information (and perhaps that's why it failed), or we might not have sufficient access. Or it might not even be a good way to rollback the action! Are there some good ways of handling such cases? EDIT: Some application details.. It's a multi user web application. Most of the work is done with scheduled jobs (through Quartz.Net), so most operations is run in it's own thread. Some user actions should trigger jobs that update several systems though. The external systems are somewhat unstable. I Was thinking of changing the application to use the Command and Unit Of Work pattern

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  • Preserving timestamps on Clojure .clj files when building shaded jar via Maven Shade Plugin

    - by Dereference
    When using the maven-shade-plugin to package our jar artifact that contained a few Clojure libs and some Java. We were using AOT compilation for our Clojure code. When we loaded the jar, it was having very slow load times. AOT compilation is supposed to help this quite a bit, but that wasn't what we were seeing. We noticed in java jar -verbose output that there was a lot of JVM__DEFINE_CLASS calls happening when Clojure classes were being loaded. This didn't make sense, since more of our Clojure code was AOT compiled to .class files. Turns out the maven-shade-plugin creates all new files, with new timestamps in the final artifact Clojure uses the timestamp information on a .clj file vs. a .class file, to determine if the file needs to be recompiled. The maven-shade-plugin was causing the .clj file and it's associated .class file to have the same timestamp, so Clojure always chose to dynamically recompile the source. The only workaround that we have been able to figure out, at this point, is to write a script that would re-open the shaded jar and bump the .clj file timestamps back to some time in the past, so that they wouldn't be equal to the timestamps of their associated .class files. Does anyone know of a better approach?

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  • Method not being resolved for dynamic generic type

    - by kelloti
    I have these types: public class GenericDao<T> { public T Save(T t) { return t; } } public abstract class DomainObject { // Some properties protected abstract dynamic Dao { get; } public virtual void Save() { var dao = Dao; dao.Save(this); } } public class Attachment : DomainObject { protected dynamic Dao { get { return new GenericDao<Attachment>(); } } } Then when I run this code it fails with RuntimeBinderException: Best overloaded method match for 'GenericDAO<Attachment.Save(Attachment)' has some invalid arguments var obj = new Attachment() { /* set properties */ }; obj.Save(); I've verified that in DomainObject.Save() "this" is definitely Attachment, so the error doesn't really make sense. Can anyone shed some light on why the method isn't resolving? Some more information - It succeeds if I change the contents of DomainObject.Save() to use reflection: public virtual void Save() { var dao = Dao; var type = dao.GetType(); var save = ((Type)type).GetMethod("Save"); save.Invoke(dao, new []{this}); }

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  • EF4 + STE: Reattaching via a WCF Service? Using a new objectcontext each and every time?

    - by Martin
    Hi there, I am planning to use WCF (not ria) in conjunction with Entity Framework 4 and STE (Self tracking entitites). If i understnad this correctly my WCF should return an entity or collection of entities (using LIST for example and not IQueryable) to the client (in my case silverlight) The client then can change the entity or update it. At this point i believe it is self tracking???? This is where i sort of get a bit confused as there are a lot of reported problems with STEs not tracking.. Anyway... Then to update i just need to send back the entity to my WCF service on another method to do the update. I should be creating a new OBJECTCONTEXT everytime? In every method? If i am creaitng a new objectcontext everytime in everymethod on my WCF then don't i need to re-attach the STE to the objectcontext? So basically this alone wouldn't work?? using(var ctx = new MyContext()) { ctx.Orders.ApplyChanges(order); ctx.SaveChanges(); } Or should i be creating the object context once in the constructor of the WCF service so that 1 call and every additional call using the same wcf instance uses the same objectcontext? I could create and destroy the wcf service in each method call from the client - hence creating in effect a new objectcontext each time. I understand that it isn't a good idea to keep the objectcontext alive for very long. Any insight or information would be gratefully appreciated thanks

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  • php how to serialize array of objects?

    - by hequ
    Hello, I have small class called 'Call' and I need to store these calls into a flat file. I've made another class called 'CallStorage' which contains an array where I put these calls into. My problem is that I would like to store this array to disk so I could later read it back and get the calls from that array. I've tried to achieve this using serialize() and unserialize() but these seems to act somehow strange and part of the information gets lost. This is what I'm doing: //write array to disk $filename = $path . 'calls-' . $today; $serialized = serialize($this->array); $fp = fopen($filename, 'a'); fwrite($fp, $serialized); fclose($fp); //read array from serialized file $filename = $path . 'calls-' . $today; if (file_exists($filename)) { $handle = fopen($filename, 'r'); $contents = fread($handle, filesize($filename)); fclose($handle); $unserialized = unserialize($contents); $this->setArray($unserialized); } Can someone see what I'm doing wrong, or what. I've also tried to serialize and write arrays that contains plain strings. I didn't manage to get that working either.. I have a Java background so I just can't see why I couldn't just write an array to disk if it's serialized. :)

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  • Can one connection get details of another? Or, how can I get the most detailed pending transaction

    - by bob-the-destroyer
    Is there a Mysql statement which provides full details of any other open connection or user? For this particular case, on myisam tables specifically. Looking at Mysql's SHOW TABLE STATUS documentation, it's missing some very important information for my purpose. For example: remote odbc connection one is inserting several thousand records, which due to a slow connection speed can take up to an hour. Tcp connection two, using PHP on the server's localhost, is running select queries with aggregate functions on that data. Before allowing connection two to run those queries, I'd like connection two to first check to make sure there's no pending inserts on any other connection on those specific tables so it can instead wait until all data is available. If the table is currently being written to, I'd like to spit back to the user of connection two an approximation of how much longer to wait based on the number of pending inserts. Ideally by table, I'd like to get back using a query the timestamp when connection one began the write, total inserts left to be done, and total inserts already completed. Instead of insert counts, even knowing number of bytes written and left to write would work just fine here. Obviously since connection two is a tcp connection via a PHP script, all I can really use in that script is some sort of query. I suppose if I have to, since it is on localhost, I can exec() it if the only way is by a mysql command line option that outputs this info, but I'd rather not. I suppose I could simply update a custom-made transaction log before and after this massive insert task which the PHP script can check, but hopefully there's already a built-in Mysql feature I can take advantage of.

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  • How to optimize a postgreSQL server for a "write once, read many"-type infrastructure ?

    - by mhu
    Greetings, I am working on a piece of software that logs entries (and related tagging) in a PostgreSQL database for storage and retrieval. We never update any data once it has been inserted; we might remove it when the entry gets too old, but this is done at most once a day. Stored entries can be retrieved by users. The insertion of new entries can happen rather fast and regularly, thus the database will commonly hold several millions elements. The tables used are pretty simple : one table for ids, raw content and insertion date; and one table storing tags and their values associated to an id. User search mostly concern tags values, so SELECTs usually consist of JOIN queries on ids on the two tables. To sum it up : 2 tables Lots of INSERT no UPDATE some DELETE, once a day at most some user-generated SELECT with JOIN huge data set What would an optimal server configuration (software and hardware, I assume for example that RAID10 could help) be for my PostgreSQL server, given these requirements ? By optimal, I mean one that allows SELECT queries taking a reasonably little amount of time. I can provide more information about the current setup (like tables, indexes ...) if needed.

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