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  • SCJP question: Method ambiguous

    - by Markos Fragkakis
    Take a look at this code: public class Test { public static void main(String... args) { flipFlop("hello", new Integer(4), 2004); // flipFlop("hello", 10, 2004); // this works! } private static void flipFlop(String str, int i, Integer iRef) { System.out.println(str + " (String, int, Integer)"); } private static void flipFlop(String str, int i, int j) { System.out.println(str + " (String, int, int)"); } } The compiler gives an error that the invocation is ambiguous: Description Resource Path Location Type The method flipFlop(String, int, Integer) is ambiguous for the type Test Test.java scjp19 - inheritence/src line 3 Java Problem But if the commented-out line is used ti invoke flip-flop, the method is unambiguously invoked (the second one, because autoboxing comes after using the primitive itself). I would expect the compiler to see that the second argument will be unboxed one way or the other, and judge what method must be invoked depending on the third argument. Why does not this happen? What is the rationale?

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  • A question about the order of pagination

    - by SpawnCxy
    Currently I'm deal with a history message page using Cakephp.And I got a problem about records' order.In the controller,codes about pagination as follows $this->paginate['Msg'] = array('order'=>'Msg.created desc'); $msgs = $this->paginate('Msg'); $this->set('historymsgs',$msgs); Then I got a page of messges like this: tom:I'm eighteen. Jerry:How old are you? tom:Tom. Jerry:what's your name? tom:Hi nice to meet you too! Jerry:Hello,nice to meet you! But what I need is the reversed order of the messages.How can I append a condition of Msg.created asc here? Thanks in advance.

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  • Bitwise AND, Bitwise Inclusive OR question, in Java

    - by Dave
    I've a few lines of code within a project, that I can't see the value of... buffer[i] = (currentByte & 0x7F) | (currentByte & 0x80); It reads the filebuffer from a file, stored as bytes, and then transfers then to buffer[i] as shown, but I can't understand what the overall purpose is, any ideas? Thanks

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  • WPF Combobox binding Question

    - by ebattulga
    I have a 2 Table. Product ProductName CategoryID Category ID CategoryName I'm filling combobox to table named 'category'. Code Product currentProduct=datacontext.products.FirstOrDefault(); this.datacontext=currentProduct; combobox1.Itemssource=datacontext.categories; XAML <Textbox Text="{Binding Path=ProductName}"></Textbox> <Combobox x:Name="combobox1" SelectedItem="Binding Path=CategoryID"></Combobox> When click save button, I'm doing datacontext.SubmitChanges() ProductName changed. But CategoryID not changed. My target is when i select from combobox, selected category ID set to CategoryID of currentProduct. (like currentProduct.CategoryID=(Category as combobox1.SelectedItem).ID) How to do is from xaml?

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  • Question about 'git branching'

    - by michael
    Hi, I read this about git branch: http://book.git-scm.com/3_basic_branching_and_merging.html so I follow it and create 1 branch : experimental And I 1. switch to experimental branch (git checkout experimental) 2. make a bunch of changes 3. commit it (git commit -a) 4. switch to master branch (git checkout master) 5. make some changes and commit there 6. switch back to experimental (git checkout experimental) 7. merge master change to experimental (git merge master) 8. there are some conflicts but after I resolve them, I did 'git add myfile' And now i am stuck, I can't move back to master when I do $ git checkout master error: Entry 'res/layout/my_item.xml' would be overwritten by merge. Cannot merge. and I did: $ git rebase --abort No rebase in progress? and I did : $ git add res/layout/socialhub_list_item.xml $ git checkout master error: Entry 'res/layout/my_item.xml' would be overwritten by merge. Cannot merge. What can I do so that I can go back to my master branch? Thank you.

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  • HttpURLConnection timeout question

    - by Malachi
    I want to return false if the URL takes more then 5 seconds to connect - how is this possible using java? Here is the code I am using to check if the URL is valid HttpURLConnection.setFollowRedirects(false); HttpURLConnection con = (HttpURLConnection) new URL(url).openConnection(); con.setRequestMethod("HEAD"); return (con.getResponseCode() == HttpURLConnection.HTTP_OK);

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  • Resilient backpropagation neural network - question about gradient

    - by Raf
    Hello Guys, First I want to say that I'm really new to neural networks and I don't understand it very good ;) I've made my first C# implementation of the backpropagation neural network. I've tested it using XOR and it looks it work. Now I would like change my implementation to use resilient backpropagation (Rprop - http://en.wikipedia.org/wiki/Rprop). The definition says: "Rprop takes into account only the sign of the partial derivative over all patterns (not the magnitude), and acts independently on each "weight". Could somebody tell me what partial derivative over all patterns is? And how should I compute this partial derivative for a neuron in hidden layer. Thanks a lot UPDATE: My implementation base on this Java code: www_.dia.fi.upm.es/~jamartin/downloads/bpnn.java My backPropagate method looks like this: public double backPropagate(double[] targets) { double error, change; // calculate error terms for output double[] output_deltas = new double[outputsNumber]; for (int k = 0; k < outputsNumber; k++) { error = targets[k] - activationsOutputs[k]; output_deltas[k] = Dsigmoid(activationsOutputs[k]) * error; } // calculate error terms for hidden double[] hidden_deltas = new double[hiddenNumber]; for (int j = 0; j < hiddenNumber; j++) { error = 0.0; for (int k = 0; k < outputsNumber; k++) { error = error + output_deltas[k] * weightsOutputs[j, k]; } hidden_deltas[j] = Dsigmoid(activationsHidden[j]) * error; } //update output weights for (int j = 0; j < hiddenNumber; j++) { for (int k = 0; k < outputsNumber; k++) { change = output_deltas[k] * activationsHidden[j]; weightsOutputs[j, k] = weightsOutputs[j, k] + learningRate * change + momentumFactor * lastChangeWeightsForMomentumOutpus[j, k]; lastChangeWeightsForMomentumOutpus[j, k] = change; } } // update input weights for (int i = 0; i < inputsNumber; i++) { for (int j = 0; j < hiddenNumber; j++) { change = hidden_deltas[j] * activationsInputs[i]; weightsInputs[i, j] = weightsInputs[i, j] + learningRate * change + momentumFactor * lastChangeWeightsForMomentumInputs[i, j]; lastChangeWeightsForMomentumInputs[i, j] = change; } } // calculate error error = 0.0; for (int k = 0; k < outputsNumber; k++) { error = error + 0.5 * (targets[k] - activationsOutputs[k]) * (targets[k] - activationsOutputs[k]); } return error; } So can I use change = hidden_deltas[j] * activationsInputs[i] variable as a gradient (partial derivative) for checking the sing?

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  • PHP and Regular Expressions question?

    - by php
    I was wondering if the codes below are the correct way to check for a street address, email address, password, city and url using preg_match using regular expressions? And if not how should I fix the preg_match code? preg_match ('/^[A-Z0-9 \'.-]{1,255}$/i', $trimmed['address']) //street address preg_match ('/^[\w.-]+@[\w.-]+\.[A-Za-z]{2,6}$/', $trimmed['email'] //email address preg_match ('/^\w{4,20}$/', $trimmed['password']) //password preg_match ('/^[A-Z \'.-]{1,255}$/i', $trimmed['city']) //city preg_match("/^[a-zA-Z]+[:\/\/]+[A-Za-z0-9\-_]+\\.+[A-Za-z0-9\.\/%&=\?\-_]+$/i", $trimmed['url']) //url

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  • question about joGL (glTexImage2D)

    - by Nour
    Hi everybody I was trying to load a texture using joGL library but it seems that something is missing when using this method glTexImage2D at : IOStream wdis = new IOStream(fileName); wdis.skipBytes(18); int width = wdis.readIntW(); // dis.skipBytes(2); int height = wdis.readIntW(); // dis.skipBytes(2); wdis.skipBytes(28); byte buf[] = new byte[wdis.available()]; wdis.read(buf); wdis.close(); gl.glBindTexture(GL.GL_TEXTURE_2D, BMPtextures[index]); gl.glTexImage2D(GL.GL_TEXTURE_2D, 0, 3, width, height, 0, GL.GL_BGR, GL.GL_UNSIGNED_BYTE, buf); gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_LINEAR); gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_LINEAR); as IOStream is a class that extends DataInputStream it shows a message that glTexImage2D(int,int,int,int,int,int,int,int,byte[]) is not found at javax.media.opengl.GL I couldn't figure the problem her because it's an open source code and it seems to work perfectly with my friends but unfortunately not with me even though we are using the same library and the same JDK version what shall I do ??

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  • XML::LibXML::XPathContext - Question

    - by sid_com
    This script works with and without XPathContext. Why should I use it with XPathContext? #!/usr/bin/env perl use warnings; use strict; use XML::LibXML; use 5.012; my $parser = XML::LibXML->new; my $doc = $parser->parse_string(<<EOT); <?xml version="1.0"?> <xml> Text im Dokument <element id="myID" name="myname" style="old" /> <object objid="001" objname="Object1" /> <element id="002" name="myname" /> </xml> EOT #/ # without XPathContext my $nodes = $doc->findnodes( '/xml/element[@id=002]' ); # with XPathContext #my $root = $doc->documentElement; #my $xc = XML::LibXML::XPathContext->new( $root ); #my $nodes = $xc->findnodes( '/xml/element[@id=002]' ); for my $node ( $nodes->get_nodelist ) { say "Node: ", $node->nodeName; print "Attribute: "; print $_->getName, '=', $_->getValue, ' ' for $node->attributes; say ""; }

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  • Basic Ruby on Rails Question about routing

    - by Acidburn2k
    I have a controller without any related model. This controller is to span some informations from various models. I have lots of actions there, which define certain views on the page. What would be the best way to organize routes for this controller. What I would like is to have /dashboard/something point to any action in the dashboard controller. Not actions like new/edit but arbitrary (showstats, etc). With trail and error I made something like this: map.dashboard 'dashboard/:action', :controller => 'dashboard', :action => :action Now it is possible to access those url using helper: dashboard_url('actionname') This approch seems to be working ok, but is this the way to go? I am not quite sure understand, how are the helper method names generated. How to generate same helper names as in basic controllers "action_controller_url" ? That would be more generic and made the code more consistent. Thanks in advance.

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  • A question about paypal IPN

    - by user304828
    i download sample code from https://cms.paypal.com/cms_content/US/en_US/files/developer/nvp_DoDirectPayment_php.txt run and get TIMESTAMP=2010%2d05%2d11T04%3a42%3a06Z&CORRELATIONID=ac15852d1e958&ACK=Failure&VERSION=51%2e0&BUILD=1268624&L_ERRORCODE0=10002&L_SHORTMESSAGE0=Security%20error&L_LONGMESSAGE0=Security%20header%20is%20not%20valid&L_SEVERITYCODE0=Error' (length=233) what is problem ? api username ? api pass ? signature or anything else ? this infor i fill in source code: // Set request-specific fields. $paymentType = urlencode('Authorization'); // or 'Sale' $firstName = urlencode('Nguyen'); $lastName = urlencode('Quang Trung'); $creditCardType = urlencode('Visa'); $creditCardNumber = urlencode(' 4111111111111111'); $expDateMonth = '04'; // Month must be padded with leading zero $padDateMonth = urlencode(str_pad($expDateMonth, 2, '0', STR_PAD_LEFT)); $expDateYear = urlencode('2015'); $cvv2Number = urlencode('5360 '); $address1 = urlencode('ha noi'); $address2 = urlencode('hcm'); $city = urlencode('ha noi'); $state = urlencode('ha noi state'); $zip = urlencode('84'); $country = urlencode('viet nam'); // US or other valid country code $amount = urlencode('900'); $currencyID = urlencode('USD'); // or other currency ('GBP', 'EUR', 'JPY', 'CAD', 'AUD')

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  • Jasper report-> page footer question

    - by raj
    If page footer data 4000 character then I want to print on first pager footer from 0 to 1750 character and next pager footer I want to print from 1751 to 3500 and next page I want to print from 3501 to 4000 characters.Can anybody help me to solve this problem. Thanks, Raj

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  • To (monkey)patch or not to (monkey)patch, that is the question

    - by gsakkis
    I was talking to a colleague about one rather unexpected/undesired behavior of some package we use. Although there is an easy fix (or at least workaround) on our end without any apparent side effect, he strongly suggested extending the relevant code by hard patching it and posting the patch upstream, hopefully to be accepted at some point in the future. In fact we maintain patches against specific versions of several packages that are applied automatically on each new build. The main argument is that this is the right thing to do, as opposed to an "ugly" workaround or a fragile monkey patch. On the other hand, I favor practicality over purity and my general rule of thumb is that "no patch" "monkey patch" "hard patch", at least for anything other than a (critical) bug fix. So I'm wondering if there is a consensus on when it's better to (hard) patch, monkey patch or just try to work around a third party package that doesn't do exactly what one would like. Does it have mainly to do with the reason for the patch (e.g. fixing a bug, modifying behavior, adding missing feature), the given package (size, complexity, maturity, developer responsiveness), something else or there are no general rules and one should decide on a case-by-case basis ?

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  • Silverlight Image Loading Question

    - by Matt
    I'm playing around with Silverlight Images and a listbox. Here's the scenario. Using WCF I grab some images out of my database and, using a custom class, add items to a listbox. It's working great right now. The images load and appear in the listbox, just like I want them to. I want to refine and improve my control just a little more so here's what I've done. <ListBox x:Name="lbMedia" Background="Transparent" ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Auto"> <ItemsControl.ItemsPanel> <ItemsPanelTemplate> <c:WrapPanel></c:WrapPanel> </ItemsPanelTemplate> </ItemsControl.ItemsPanel> <ItemsControl.ItemTemplate> <DataTemplate> <im:MediaManagerItem></im:MediaManagerItem> </DataTemplate> </ItemsControl.ItemTemplate> </ListBox> Just a simple listbox. The datatemplate is a custom control and literally it contains a contentpresenter, nothing more. Now the class that I use as the ItemSource has a Source property. Here's what it looks like. private UIElement _LoadingSource; private UIElement _Source; public UIElement Source { get { if( _Source == null ) { LoadMedia(); return new LoadingElement(); } return _Source; } set { if( !( value is Image ) && !( value is MediaElement ) ) throw new Exception( "Media Source must be an Image or MediaElement" ); _Source = value; NotifyPropertyChanged( "Source" ); } } Essentially, on the get I check if the image/video has been loaded from the server. If it hasn't I return a loading control, then I proceed to load my image. Here's the code for my LoadMedia method. private void LoadMedia() { if( _Media != null && _Media.MediaId > 0 ) { //load the media BackgroundWorker mediaLoader = new BackgroundWorker(); mediaLoader.DoWork += mediaLoader_DoWork; mediaLoader.RunWorkerCompleted += mediaLoader_RunWorkerCompleted; mediaLoader.RunWorkerAsync(); } } void mediaLoader_RunWorkerCompleted( object sender, RunWorkerCompletedEventArgs e ) { if(_LoadingSource != null) Source = _LoadingSource; } void mediaLoader_DoWork( object sender, DoWorkEventArgs e ) { string url = App.siteUrl + "download.ashx?MediaId=" + _Media.MediaId; SmartDispatcher.BeginInvoke( () => { Image img = new Image(); img.Source = new BitmapImage( new Uri( url, UriKind.Absolute ) ); _LoadingSource = img; } ); } So as the code goes, I create a new image element, and set the Uri. The images that I'm downloading take about 2-5 seconds to download. Now for the problem / fine tuning. Right now my code will check if the source is null and if it is, return a loading element, and run the background worker to get the image. Once the background worker finishes, set the source to the new downloaded image. I want to be able to set the Source property AFTER the image has fully downloaded. Right now my loading element appears for a brief second, then there's nothing for 2-5 seconds until the image finishes downloading. I want the loading elements to stick around until the image is completely ready but I'm having troubles doing this. I've tried adding a a listener to the ImageOpened event and update the Source property then, but it doesn't work. Thanks in advance.

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  • LINQ-to-XML selection based on node values, newbie question

    - by mmcglynn
    Given the following XML, I would like to return all eventtitles where the eventtype id = 23. My current query only looks at the first eventtype, so returns the wrong result. <event> <eventtitle>Garrison Keillor</eventtitle> <eventtypes> <eventtype id="24"/> <eventtype id="23"/> </eventtypes> </event> <event> <eventtitle>Joe Krown Trio featuring Walter Wolfman Washington</eventtitle> <eventtypes> <eventtype id="23"/> </eventtypes> </event> LINQ query: Dim query = _ From c In calXML...<event> _ Where c...<eventtypes>.<eventtype>.@id = "23" _ Select c.<eventtitle>.Value, c.<eventlocation>.Value For Each item In query Response.Write("<h3>" & item.eventtitle & "</h3>") Response.Write(item.eventlocation & "<br />") Next

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  • another porter stemming algorithm implementation question ?

    - by mike
    Hi, I am trying to implement porter stemming algorithm, but i am having difficualties understanding this point Step 1c (*v*) Y -> I happy -> happi sky -> sky Isn't that the the opposite of what we want to do , why does the algorithim convert the Y into I. for the complete algorithm here http://tartarus.org/~martin/PorterStemmer/def.txt Thanks

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  • Validate a string in a table in SQL Server - CLR function or T-SQL (Question updated)

    - by Ashish Gupta
    I need to check If a column value (string) in SQL server table starts with a small letter and can only contain '_', '-', numbers and alphabets. I know I can use a SQL server CLR function for that. However, I am trying to implement that validation using a scalar UDF and could make very little here...I can use 'NOT LIKE', but I am not sure how to make sure I validate the string irrespective of the order of characters or in other words write a pattern in SQL for this. Am I better off using a SQL CLR function? Any help will be appreciated.. Thanks in advance Thank you everyone for their comments. This morning, I chose to go CLR function way. For the purpose of what I was trying to achieve, I created one CLR function which does the validation of an input string and have that called from a SQL UDF and It works well. Just to measure the performance of t-SQL UDF using SQL CLR function vs t- SQL UDF, I created a SQL CLR function which will just check if the input string contains only small letters, it should return true else false and have that called from a UDF (IsLowerCaseCLR). After that I also created a regular t-SQL UDF(IsLowerCaseTSQL) which does the same thing using the 'NOT LIKE'. Then I created a table (Person) with columns Name(varchar) and IsValid(bit) columns and populate that with names to test. Data :- 1000 records with 'Ashish' as value for Name column 1000 records with 'ashish' as value for Name column then I ran the following :- UPDATE Person Set IsValid=1 WHERE dbo.IsLowerCaseTSQL (Name) Above updated 1000 records (with Isvalid=1) and took less than a second. I deleted all the data in the table and repopulated the same with same data. Then updated the same table using Sql CLR UDF (with Isvalid=1) and this took 3 seconds! If update happens for 5000 records, regular UDF takes 0 seconds compared to CLR UDF which takes 16 seconds! I am very less knowledgeable on t-SQL regular expression or I could have tested my actual more complex validation criteria. But I just wanted to know, even I could have written that, would that have been faster than the SQL CLR function considering the example above. Are we using SQL CLR because we can implement we can implement lot richer logic which would have been difficult otherwise If we write in regular SQL. Sorry for this long post. I just want to know from the experts. Please feel free to ask if you could not understand anything here. Thank you again for your time.

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  • sharp architecture question

    - by csetzkorn
    I am trying to get my head around the sharp architecture and follow the tutorial. I am using this code: using Bla.Core; using System.Collections.Generic; using Bla.Core.DataInterfaces; using System.Web.Mvc; using SharpArch.Core; using SharpArch.Web; using Bla.Web; namespace Bla.Web.Controllers { public class UsersController { public UsersController(IUserRepository userRepository) { Check.Require(userRepository != null,"userRepository may not be null"); this.userRepository = userRepository; } public ActionResult ListStaffMembersMatching(string filter) { List<User> matchingUsers = userRepository.FindAllMatching(filter); return View("ListUsersMatchingFilter", matchingUsers); } private readonly IUserRepository userRepository; } } I get this error: The name 'View' does not exist in the current context I have used all the correct using statements and referenced the assemblies as far as I can see. The views live in Bla.Web in this architecture. Can anyone see the problem? Thanks. Christian

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