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  • Building a calendar navigation in Rails (controller and view links)

    - by user532339
    Trying to get the next month when clicking the link_to. I've done the following in the view. <%= form_tag rota_days_path, :method => 'get' do %> <p> <%= hidden_field_tag(:next_month, @t1) %> <%= link_to 'Next Month', rota_days_path(:next_month => @next_month)%> </p> <% end %> class RotaDaysController < ApplicationController # GET /rota_days # GET /rota_days.json # load_and_authorize_resource respond_to :json, :html def index @rota_days = RotaDay.all @hospitals = Hospital.all @t1 = Date.today.at_beginning_of_month @t2 = Date.today.end_of_month @dates = (@t1..@t2) #Concat variable t1 + t2 together # @next_month = Date.today + 1.month(params[: ??? ] #Old if params[:next_month] # @next_month = Date.today >> 1 @next_month = params[:next_month] + 1.month @t1 = @next_month.at_beginning_of_month @t2 = @next_month.end_of_month @dates = (@t1..@t2) end @title = "Rota" respond_to do |format| format.html # index.html.erb format.json { render json: @rota_days } end end I have identified that the reason why this may not be working is in because of the following in my controller @next_month = params[:next_month] + 1.month the last two called methods is defined only on time/date objects. but not on fixnum/string objects. I understand I am missing something from this Update I have found that the actual issue is that the `params[:next_month] is a string and I am trying to add a date to to it. Which means I need to convert the string to a date/time object. Console output: Started GET "/rota_days" for 127.0.0.1 at 2012-12-14 22:14:36 +0000 Processing by RotaDaysController#index as HTML User Load (0.0ms) SELECT `users`.* FROM `users` WHERE `users`.`id` = 1 LIMIT 1 RotaDay Load (0.0ms) SELECT `rota_days`.* FROM `rota_days` Hospital Load (1.0ms) SELECT `hospitals`.* FROM `hospitals` Rendered rota_days/index.html.erb within layouts/application (23.0ms) Role Load (0.0ms) SELECT `roles`.* FROM `roles` INNER JOIN `roles_users` ON `roles`.`id` = `roles_users`.`role_id` WHERE `roles_users`.`user_id` = 1 AND `roles`.`name` = 'Administrator' LIMIT 1 Completed 200 OK in 42ms (Views: 39.0ms | ActiveRecord: 1.0ms)

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  • Cleaner method for list comprehension clean-up

    - by Dan McGrath
    This relates to my previous question: Converting from nested lists to a delimited string I have an external service that sends data to us in a delimited string format. It is lists of items, up to 3 levels deep. Level 1 is delimited by '|'. Level 2 is delimited by ';' and level 3 is delimited by ','. Each level or element can have 0 or more items. An simplified example is: a,b;c,d|e||f,g|h;; We have a function that converts this to nested lists which is how it is manipulated in Python. def dyn_to_lists(dyn): return [[[c for c in b.split(',')] for b in a.split(';')] for a in dyn.split('|')] For the example above, this function results in the following: >>> dyn = "a,b;c,d|e||f,g|h;;" >>> print (dyn_to_lists(dyn)) [[['a', 'b'], ['c', 'd']], [['e']], [['']], [['f', 'g']], [['h'], [''], ['']]] For lists, at any level, with only one item, we want it as a scalar rather than a 1 item list. For lists that are empty, we want them as just an empty string. I've came up with this function, which does work: def dyn_to_min_lists(dyn): def compress(x): return "" if len(x) == 0 else x if len(x) != 1 else x[0] return compress([compress([compress([item for item in mv.split(',')]) for mv in attr.split(';')]) for attr in dyn.split('|')]) Using this function and using the example above, it returns: [[['a', 'b'], ['c', 'd']], 'e', '', ['f', 'g'], ['h', '', '']] Being new to Python, I'm not confident this is the best way to do it. Are there any cleaner ways to handle this? This will potentially have large amounts of data passing through it, are there any more efficient/scalable ways to achieve this?

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  • Strange behavior when overloading methods in Java

    - by Sep
    I came across this weird (in my opinion) behavior today. Take this simple Test class: public class Test { public static void main(String[] args) { Test t = new Test(); t.run(); } private void run() { List<Object> list = new ArrayList<Object>(); list.add(new Object()); list.add(new Object()); method(list); } public void method(Object o) { System.out.println("Object"); } public void method(List<Object> o) { System.out.println("List of Objects"); } } It behaves the way you expect, printing "List of Objects". But if you change the following three lines: List<String> list = new ArrayList<String>(); list.add(""); list.add(""); you will get "Object" instead. I tried this a few other ways and got the same result. Is this a bug or is it a normal behavior? And if it is normal, can someone explain why? Thanks.

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  • TCP socket communication

    - by raven
    hello, I am creating a Chat in java. I have a method (onMouseRelease) inside an object that creates a tcp server and waits for a socket like this: ServerSocket server = new ServerSocket(port); Socket channel = server.accept(); Now I want to make a thread that will loop and read data from the socket, so that once the user on the other side sends me a string, I will extract the data from the socket (or is it called packet? Sorry, I am new to this) and update a textbox to add the additional string from the socket (or packet?). I have no idea how to READ (extract) the information from the socket(/packet) and then update it into a JTextArea which is called userOutput. And how to send a string to the other client, so that it will also could read the new data and update its JTextArea. From what I know, for a 2 sided TCP communication you need one computer to host a server and the other to connect (as a client) and once the connection is set the client can also receive new information from the socket. Is that true? and please tell me how. Any help is appreciated! I know this is a bit long but I have searched a lot and didn't understand it (I saw something like PrintWriter but failed to understand).

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  • C# Generic Generics (A Serious Question)

    - by tahirhassan
    In C# I am trying to write code where I would be creating a Func delegate which is in itself generic. For example the following (non-Generic) delegate is returning an arbitrary string: Func<string> getString = () => "Hello!"; I on the other hand want to create a generic which acts similarly to generic methods. For example if I want a generic Func to return default(T) for a type T. I would imagine that I write code as follows: Func<T><T> getDefaultObject = <T>() => default(T); Then I would use it as getDefaultObject<string>() which would return null and if I were to write getDefaultObject<int>() would return 0. This question is not merely an academic excercise. I have found numerous places where I could have used this but I cannot get the syntax right. Is this possible? Are there any libraries which provide this sort of functionality?

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  • C#: How to implement a smart cache

    - by Svish
    I have some places where implementing some sort of cache might be useful. For example in cases of doing resource lookups based on custom strings, finding names of properties using reflection, or to have only one PropertyChangedEventArgs per property name. A simple example of the last one: public static class Cache { private static Dictionary<string, PropertyChangedEventArgs> cache; static Cache() { cache = new Dictionary<string, PropertyChangedEventArgs>(); } public static PropertyChangedEventArgs GetPropertyChangedEventArgsa(string propertyName) { if (cache.ContainsKey(propertyName)) return cache[propertyName]; return cache[propertyName] = new PropertyChangedEventArgs(propertyName); } } But, will this work well? For example if we had a whole load of different propertyNames, that would mean we would end up with a huge cache sitting there never being garbage collected or anything. I'm imagining if what is cached are larger values and if the application is a long-running one, this might end up as kind of a problem... or what do you think? How should a good cache be implemented? Is this one good enough for most purposes? Any examples of some nice cache implementations that are not too hard to understand or way too complex to implement?

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  • Cannot connect to mysql via servlet

    - by JBoy
    Hi all I have been since 2 days trying to figure out why my servlet does not connect to the database MySql. I have mysql installed and working properly and eclipse. Whenever i try to etabilish a connection i get the ClassNotFoundException for the com.mysql.jdbc.Driver, which is actually properly imported, the connector i'm using is the mysql-connector-java5.1.14 added properly as external jar so everything seems fine. here's my code protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String dbUrl="jdbc:mysql://localhost:3306/test"; String username="root"; String password=""; try { Class.forName("com.mysql.jdbc.Driver").newInstance(); conn=DriverManager.getConnection(dbUrl); System.out.println("Connected!"); } catch (SQLException e) { e.printStackTrace(); System.out.println("not connected"); } catch(ClassNotFoundException x){ x.printStackTrace(); } catch(Exception e){ e.printStackTrace(); } } The stacktrace(part of): java.lang.ClassNotFoundException: com.mysql.jdbc.Driver at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1645) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1491) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:375) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:164) i'm following the connection steps from a published java book and also in forums and tutorials i just see the same code, cannot figure out why that Exception comes. On a normal application which does not run on the server the Exception isn't thrown and the connection (in the exact same way) its successfull. Do you have any advice?

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  • ref and out parameters in C# and cannot be marked as variant.

    - by Water Cooler v2
    What does the statement mean? From here ref and out parameters in C# and cannot be marked as variant. 1) Does it mean that the following can not be done. public class SomeClass<R, A>: IVariant<R, A> { public virtual R DoSomething( ref A args ) { return null; } } 2) Or does it mean I cannot have the following. public delegate R Reader<out R, in A>(A arg, string s); public static void AssignReadFromPeonMethodToDelegate(ref Reader<object, Peon> pReader) { pReader = ReadFromPeon; } static object ReadFromPeon(Peon p, string propertyName) { return p.GetType().GetField(propertyName).GetValue(p); } static Reader<object, Peon> pReader; static void Main(string[] args) { AssignReadFromPeonMethodToDelegate(ref pReader); bCanReadWrite = (bool)pReader(peon, "CanReadWrite"); Console.WriteLine("Press any key to quit..."); Console.ReadKey(); } I tried (2) and it worked.

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  • Google Sites API - File Cabinets: Spaces and extension separator (.) are removed from file names

    - by user1299447
    We have a series of internal reports that we update regularly from our internal databases. We built an application in C# that uploads these reports to a Google Site. Everything works fine, except that the name of the file shown to the final user in the File Cabinet does not include the original spaces nor the extension separator (.) For example, Stock per warehouse.pdf is shown as : Stockperwarehousepdf Below is a simplified version of the code. private AtomEntry UploadAttachment(string filename, AtomEntry parent, string title, string description) { SiteEntry entry = new SiteEntry(); AtomCategory category = new AtomCategory(SitesService.ATTACHMENT_TERM, SitesService.KIND_SCHEME); category.Label = "attachment"; entry.Categories.Add(category); AtomLink parentLink = new AtomLink(AtomLink.ATOM_TYPE, SitesService.PARENT_REL); parentLink.HRef = parent.SelfUri; entry.Links.Add(parentLink); entry.MediaSource = new MediaFileSource(filename, MediaFileSource.GetContentTypeForFileName(filename)); entry.Content.Type = MediaFileSource.GetContentTypeForFileName(filename); entry.Title.Text= title; entry.Summary.Text = description; AtomEntry newEntry = null; newEntry = service.Insert(new Uri(makeFeedUri("content")), entry); } The key line is where the MediaFileSource object is created. Any idea of what we are missing? I've tried all sort of changes :(

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  • SQL Server Connection Timeout C#

    - by Termin8tor
    First off I'd like to let everyone know I have searched my particular problem and can't seem to find what's causing my problem. I have an SQL Server 2008 instance running on a network machine and a client I have written connecting to it. To connect I have a small segment of code that establishes a connection to an sql server 2008 instance and returns a DataTable populated with the results of whatever query I run against the server, all pretty standard stuff really. Anyway the issue is, whenever I open my program and call this method, upon the first call to my method, regardless as to what I've set my Connection Timeout value as in the connection string, it takes about 15 seconds and then times out. Bizarrely though the second or third call I make to the method will work without a problem. I have opened up the ports for SQL Server on the server machine as outlined in this article: How to Open firewall ports for SQL Server and verified that it is correctly configured. Can anyone see a particular problem in my code? string _connectionString = "Server=" + @Properties.Settings.Default.sqlServer + "; Initial Catalog=" + @Properties.Settings.Default.sqlInitialCatalog + ";User Id=" + @Properties.Settings.Default.sqlUsername + ";Password=" + @Properties.Settings.Default.sqlPassword + "; Connection Timeout=1"; private DataTable ExecuteSqlStatement(string command) { using (SqlConnection conn = new SqlConnection(_connectionString)) { try { conn.Open(); using (SqlDataAdapter adaptor = new SqlDataAdapter(command, conn)) { DataTable table = new DataTable(); adaptor.Fill(table); return table; } } catch (SqlException e) { throw e; } } } The SqlException that is caught at my catch is : "Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding." This occurs at the conn.Open(); line in the code snippet I have included. If anyone has any ideas that'd be great!

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  • Saving a Record with Rails Association

    - by tshauck
    Hi, I've been going through the Rails Guides, but have gotten stuck on associations after going through validations and migrations. So, I have the following models Job and Person, where a Person can have many jobs. I know that in reality there'd be a many-to-many, but I'm trying to get my handle on this first. class Job < ActiveRecord::Base belongs_to :people end and class Person < ActiveRecord::Base has_many :jobs end Here's the schema ActiveRecord::Schema.define(:version => 20110108185924) do create_table "jobs", :force => true do |t| t.string "occupation" t.boolean "like" t.datetime "created_at" t.datetime "updated_at" t.integer "person_id" end create_table "people", :force => true do |t| t.string "first_name" t.string "last_name" t.datetime "created_at" t.datetime "updated_at" end end Is there some I can do the following j = Job.first; j.Person? Then that'd give me access to the Person object associated with the j. I couldn't find it on guides.rubyonrails.org, although it has been very helpful getting a grip on migrations and validations thus far. Thanks PS, If there are any tutorials that covers more of this kind of things links would be great.

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  • list all files from directories and subdirectories in Java

    - by Adnan
    What would be the fastest way to list the names of files from 1000+ directories and sub-directories? EDIT; The current code I use is: import java.io.File; public class DirectoryReader { static int spc_count=-1; static void Process(File aFile) { spc_count++; String spcs = ""; for (int i = 0; i < spc_count; i++) spcs += " "; if(aFile.isFile()) System.out.println(spcs + "[FILE] " + aFile.getName()); else if (aFile.isDirectory()) { System.out.println(spcs + "[DIR] " + aFile.getName()); File[] listOfFiles = aFile.listFiles(); if(listOfFiles!=null) { for (int i = 0; i < listOfFiles.length; i++) Process(listOfFiles[i]); } else { System.out.println(spcs + " [ACCESS DENIED]"); } } spc_count--; } public static void main(String[] args) { String nam = "D:/"; File aFile = new File(nam); Process(aFile); } }

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  • C# language questions

    - by Water Cooler v2
    1) What is int? Is it any different from the struct System.Int32? I understand that the former is a C# alias (typedef or #define equivalant) for the CLR type System.Int32. Is this understanding correct? 2) When we say: IComparable x = 10; Is that like saying: IComparable x = new System.Int32(); But we can't new a struct, right? or in C like syntax: struct System.In32 *x; x=>someThing = 10; 3) What is String with a capitalized S? I see in Reflector that it is the sealed String class, which, of course, is a reference type, unlike the System.Int32 above, which is a value type. What is string, with an uncapitalized s, though? Is that also the C# alias for this class? Why can I not see the alias definitions in Reflector? 4) Try to follow me down this subtle train of thought, if you please. We know that a storage location of a particular type can only access properties and members on its interface. That means: Person p = new Customer(); p.Name = "Water Cooler v2"; // legal because as Name is defined on Person. but // illegal without an explicit cast even though the backing // store is a Customer, the storage location is of type // Person, which doesn't support the member/method being // accessed/called. p.GetTotalValueOfOrdersMade(); Now, with that inference, consider this scenario: int i = 10; // obvious System.object defines no member to // store an integer value or any other value in. // So, my question really is, when the integer is // boxed, what is the *type* it is actually boxed to. // In other words, what is the type that forms the // backing store on the heap, for this operation? object x = i;

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  • Nullable object must have a value. VB.NET

    - by Glenn05
    I need help. I'm having problem in my program. This is my code on my Business logic layer. Function Load_ItemDetails(ByVal ItemID As String) As Items Dim objItemEnt As New tblitem Dim objitem As New Items Try Using da = New DataAccess objItemEnt = da.Load_ItemDetails(ItemID) With objitem .ItemCode = objItemEnt.ItemCode .ItemName = objItemEnt.ItemName .Description = objItemEnt.Description .NameofType = objItemEnt.NameofType .TypeofPricing = objItemEnt.TypeofPricing .OnStock = objItemEnt.OnStock .ItemPrice = objItemEnt.ItemPrice .DateModified = objItemEnt.DateModified End With Return objitem End Using Catch ex As Exception Throw End Try End Function This code is for my data access layer. Public Function Load_ItemDetails(ByVal ItemCode As String) Dim objitem As New tblitem Try Using entItem = New DAL.systemdbEntities1 Dim qryUsers = From p In entItem.tblitems Where p.ItemCode = ItemCode Select p Dim luser As List(Of tblitem) = qryUsers.ToList If luser.Count > 0 Then Return luser.First Else Return objitem End If End Using Catch ex As Exception Throw End Try End Function` For my Presentation layer: Private Sub Load_Item_Detail(ByVal ItemCode As String) objItem = New Items Using objLogic = New LogicalLayer objItem = objLogic.Load_ItemDetails(ItemCode) With objItem Me.ItemCodetxt.Text = .ItemCode Me.ItemNametxt.Text = .ItemName Me.ItemDesctxt.Text = .Description Me.ItemTypetxt.Text = .NameofType Me.ItemPricetxt.Text = .TypeofPricing Me.ItemOnstocktxt.Text = CStr(.OnStock) Me.ItemPricetxt.Text = CStr(.ItemPrice) Me.TextBox1.Text = CStr(.DateModified) Me.ItemCodetxt.Tag = .ItemCode End With End Using End Sub` and after I run, I get this error Nullable object must have a value help me. I'm stuck. I don't know what to do guys. I new in n tier architecture.

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  • Tracking changed (unsaved) objects

    - by Eric
    I have a class which is serialized to and from an XML file when the user decided to open or save. I'm trying to add the typical functionality where when they try to close the form with un-saved changes the form warns them and gives them the option of saving before closing. I've added a HasUnsavedChanges property to my class, which my form checks before closing. However, it's a little annoying that my properties have changed from something like this .. public string Name { get; set; } to this... private string _Name; public string Name { get { return _Name; } set { this._Name = value; this.HasUnsavedChanges = true; } } Is there a better way to track changes to an instance of a class? For example is there some standard way I can "hash" an instance of a class into a value that I can use to compare the most recent version with the saved version without mucking up every property in the class?

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  • c# How to implement a collection of generics

    - by Amy
    I have a worker class that does stuff with a collection of objects. I need each of those objects to have two properties, one has an unknown type and one has to be a number. I wanted to use an interface so that I could have multiple item classes that allowed for other properties but were forced to have the PropA and PropB that the worker class requires. This is the code I have so far, which seemed to be OK until I tried to use it. A list of MyItem is not allowed to be passed as a list of IItem even though MyItem implements IItem. This is where I got confused. Also, if possible, it would be great if when instantiating the worker class I don't need to pass in the T, instead it would know what T is based on the type of PropA. Can someone help get me sorted out? Thanks! public interface IItem<T> { T PropA { get; set; } decimal PropB { get; set; } } public class MyItem : IItem<string> { public string PropA { get; set; } public decimal PropB { get; set; } } public class WorkerClass<T> { private List<T> _list; public WorkerClass(IEnumerable<IItem<T>> items) { doStuff(items); } public T ReturnAnItem() { return _list[0]; } private void doStuff(IEnumerable<IItem<T>> items) { foreach (IItem<T> item in items) { _list.Add(item.PropA); } } } public void usage() { IEnumerable<MyItem> list= GetItems(); var worker = new WorkerClass<string>(list);//Not Allowed }

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  • changes in main.xml are not reflected in the android app in netbeans

    - by nitish712
    I am new to android apps. I am using the netbeans 7.0.1 IDE to develop android apps. I have written the following code in the main java file: package com.test.helloworld; import android.app.Activity; import android.os.Bundle; import android.widget.TextView; public class helloworld extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); TextView t1=new TextView(this); t1.setText("hello world..!!!!"); setContentView(t1); } } This was working fine. I edited the main.xml file to display a textfield and button as follows: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/button_send"/> <EditText android:id="@+id/edit_message" android:layout_width="wrap_content" android:layout_height="wrap_content" android:hint="@string/edit_message"/> </LinearLayout> Of course I have added all the corresponding strings in strings.xml. But when I try to run my app these weren't displaying... :( . I mean the same string that was displayed previously was being displayed. Can anybody figure out what is the mistake? thanx...

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  • actionscript find and convert text to url

    - by gravesit
    I have this script that grabs a twitter feed and displays in a little widget. What I want to do is look at the text for a url and convert that url to a link. public class Main extends MovieClip { private var twitterXML:XML; // This holds the xml data public function Main() { // This is Untold Entertainment's Twitter id. Did you grab yours? var myTwitterID= "username"; // Fire the loadTwitterXML method, passing it the url to your Twitter info: loadTwitterXML("http://twitter.com/statuses/user_timeline/" + myTwitterID + ".xml"); } private function loadTwitterXML(URL:String):void { var urlLoader:URLLoader = new URLLoader(); // When all the junk has been pulled in from the url, we'll fire finishedLoadingXML: urlLoader.addEventListener(Event.COMPLETE, finishLoadingXML); urlLoader.load(new URLRequest(URL)); } private function finishLoadingXML(e:Event = null):void { // All the junk has been pulled in from the xml! Hooray! // Remove the eventListener as a bit of housecleaning: e.target.removeEventListener(Event.COMPLETE, finishLoadingXML); // Populate the xml object with the xml data: twitterXML = new XML(e.target.data); showTwitterStatus(); } private function addTextToField(text:String,field:TextField):void{ /*Regular expressions for replacement, g: replace all, i: no lower/upper case difference Finds all strings starting with "http://", followed by any number of characters niether space nor new line.*/ var reg:RegExp=/(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig; //Replaces Note: "$&" stands for the replaced string. text.replace(reg,"<a href=\"$&\">$&</a>"); field.htmlText=text; } private function showTwitterStatus():void { // Uncomment this line if you want to see all the fun stuff Twitter sends you: //trace(twitterXML); // Prep the text field to hold our latest Twitter update: twitter_txt.wordWrap = true; twitter_txt.autoSize = TextFieldAutoSize.LEFT; // Populate the text field with the first element in the status.text nodes: addTextToField(twitterXML.status.text[0], twitter_txt); }

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  • I asked a question about arrays before, but this one won't compile

    - by unit
    I asked about this array a little while ago, and I can't see what the problem is. Too tired. What have I done wrong? Basically, I am taking a string array and trying to check to see if it contains numbers or an x (ISBN number validation). I want to take the number from a given input (bookNum), check the input, and feed any valid input into a new array (book). At the line 'bookNum.charAt[j]==book[i]' I get the 'not a statement error'. What gives? String[] book = new String [ISBN_NUM]; bookNum.replaceAll("-",""); if (bookNum.length()!=ISBN_NUM) throw new ISBNException ("ISBN "+ bookNum + " must be 10 characters"); for (int i=0;i<bookNum.length();i++) { if (Character.isDigit(bookNum.charAt(i))) bookNum.CharAt[j]==book[i]; j++; if (book[9].isNotDigit()|| book[9]!="x" || book[9]!="X") throw new ISBNException ("ISBN " + bookNum + " must contain all digits" + "or 'X' in the last position");

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  • Minimal framework in Scala for collections with inheriting return type

    - by Rex Kerr
    Suppose one wants to build a novel generic class, Novel[A]. This class will contain lots of useful methods--perhaps it is a type of collection--and therefore you want to subclass it. But you want the methods to return the type of the subclass, not the original type. In Scala 2.8, what is the minimal amount of work one has to do so that methods of that class will return the relevant subclass, not the original? For example, class Novel[A] /* What goes here? */ { /* Must you have stuff here? */ def reverse/* What goes here instead of :Novel[A]? */ = //... def revrev/*?*/ = reverse.reverse } class ShortStory[A] extends Novel[A] /* What goes here? */ { override def reverse: /*?*/ = //... } val ss = new ShortStory[String] val ss2 = ss.revrev // Type had better be ShortStory[String], not Novel[String] Does this minimal amount change if you want Novel to be covariant? (The 2.8 collections do this among other things, but they also play with return types in more fancy (and useful) ways--the question is how little framework one can get away with if one only wants this subtypes-always-return-subtypes feature.)

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  • javascript freezeing ie8

    - by florin
    Can someone tell me why does this code freeze ie8? It is supposed to generate input fields. In firefox, safari, chrome it works, but in in8 when i press generate button it freezes var monthNames = [ "Ianuarie", "Februarie", "Martie", "Aprilie", "Mai", "Iunie", "Iulie", "August", "Septembrie", "Octombrie", "Noiembrie", "Decembrie" ]; function buildMonthlyEntries() { var startDate = new Date(document.getElementById('datastart').value); var endDate = new Date(document.getElementById('dataend').value); if (startDate == "Invalid Date" || endDate == "Invalid Date") { return null; } var monthlyEntries = document.getElementById('monthlyEntries'); monthlyEntries.innerHTML = ""; // inclusiv dataend endDate.setMonth(endDate.getMonth() + 1); // start with startDate; loop until we reach endDate for (var dt = startDate; ! ( dt.getFullYear() == endDate.getFullYear() && dt.getMonth() == endDate.getMonth() ); dt.setMonth( dt.getMonth() + 1 ) ) { monthlyEntries.appendChild( document.createTextNode( monthNames[dt.getMonth()] + " " + String(dt.getFullYear()).substring(2) ) ); var textElement = document.createElement('input'); var textElement2 = document.createElement('input'); var textElement3 = document.createElement('input'); textElement.setAttribute('type', 'text'); //textElement.setAttribute('name', 'entry['+ monthNames[dt.getMonth()] + + String(dt.getFullYear()).substring(2) + ']'); textElement.setAttribute('name', 'entry[]'); textElement2.setAttribute('type', 'hidden'); textElement2.setAttribute('name', 'luna[]'); textElement2.setAttribute('value', '' + monthNames[dt.getMonth()] + ''); textElement3.setAttribute('type', 'hidden'); textElement3.setAttribute('name', 'an[]'); textElement3.setAttribute('value', '' + String(dt.getFullYear()) + ''); monthlyEntries.appendChild(textElement); monthlyEntries.appendChild(textElement2); monthlyEntries.appendChild(textElement3); // adauga br // monthlyEntries.appendChild(document.createElement("br")); } return null; }

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  • Null Pointer Exception

    - by user1507835
    I am getting a null pointer exception, but I dont know why. I checked to see if the cell was null before I read it to a string. So, why is that string null? private void fillArray() private void fillArray() { try { readBook = new HSSFWorkbook(readFile); } catch (IOException e) { System.out .println("If we know what we're doing, no one should ever see this line."); } if (readBook != null) {HSSFSheet infoSheet = readBook.getSheetAt(0); HSSFRow headingsRow = infoSheet.getRow(0); int i = 0; HSSFCell cell = headingsRow.getCell(i); String columnHeading = cell.toString(); while (cell != null && !(cell.toString().equals(""))) { cell = headingsRow.getCell(i); columnHeading = cell.toString(); columnHeadings.add(columnHeading); i++; } if(columnListIsSetup == false) { createList(); columnListIsSetup = true; } }

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  • Why my oracleParameter doesnt work?

    - by user1824356
    I'm a .NET developer and this is the first time i work with oracle provider (Oracle 10g and Framework 4.0). When i add parameter to my command in this way: objCommand.Parameters.Add("pc_cod_id", OracleType.VarChar, 4000).Value = codId; objCommand.Parameters.Add("pc_num_id", OracleType.VarChar, 4000).Value = numId; objCommand.Parameters.Add("return_value", OracleType.Number).Direction = ParameterDirection.ReturnValue; objCommand.Parameters.Add("pc_email", OracleType.VarChar, 4000).Direction = ParameterDirection.Output; I have no problem with the result. But when a add parameter in this way: objCommand.Parameters.Add(CreateParameter(PC_COD_ID, OracleType.VarChar, codId, ParameterDirection.Input)); objCommand.Parameters.Add(CreateParameter(PC_NUM_ID, OracleType.VarChar, numId, ParameterDirection.Input)); objCommand.Parameters.Add(CreateParameter(RETURN_VALUE, OracleType.Number, ParameterDirection.ReturnValue)); objCommand.Parameters.Add(CreateParameter(PC_EMAIL, OracleType.VarChar, ParameterDirection.Output)); The implementation of that function is: protected OracleParameter CreateParameter(string name, OracleType type, ParameterDirection direction) { OracleParameter objParametro = new OracleParameter(name, type); objParametro.Direction = direction; if (type== OracleType.VarChar) { objParametro.Size = 4000; } return objParametro; } All my result are a empty string. My question is, these way to add parameters are not the same? And if no, what is the difference? Thanks :) Add: Sorry i forgot mention "CreateParameter" is a function with multiple implementations the base is the above function, the other use that. protected OracleParameter CreateParameter(string name, OracleType type, object value, ParameterDirection direction) { OracleParameter objParametro = CreateParameter(name, type, value); objParametro.Direction = direction; return objParametro; } The last parameters doesn't need value because those are output parameter, those bring me data from the database.

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  • "Syntax error in INSERT INTO statement". Why?

    - by Kevin
    My code is below. I have a method where I pass in three parameters and they get written out to an MS Access database table. However, I keep getting a syntax error message. Can anyone tell me why? I got this example from the internet. private static void insertRecord(string day, int hour, int loadKW) { string connString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\LoadForecastDB.accdb"; OleDbConnection conn = new OleDbConnection(connString); string ins = @"INSERT INTO Forecasts (Day, Hour, Load) VALUES (?,?,?)"; OleDbCommand cmd = new OleDbCommand(ins, conn); cmd.Parameters.Add("@day", OleDbType.VarChar).Value = day; cmd.Parameters.Add("@hour", OleDbType.Integer).Value = hour; cmd.Parameters.Add("@load", OleDbType.Integer).Value = loadKW; conn.Open(); try { int count = cmd.ExecuteNonQuery(); } catch (OleDbException ex) { Console.WriteLine(ex.Message); } finally { conn.Close(); } }

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  • safe structures embedded systems

    - by user405633
    I have a packet from a server which is parsed in an embedded system. I need to parse it in a very efficient way, avoiding memory issues, like overlapping, corrupting my memory and others variables. The packet has this structure "String A:String B:String C". As example, here the packet received is compounded of three parts separated using a separator ":", all these parts must be accesibles from an structure. Which is the most efficient and safe way to do this. A.- Creating an structure with attributes (partA, PartB PartC) sized with a criteria based on avoid exceed this sized from the source of the packet, and attaching also an index with the length of each part in a way to avoid extracting garbage, this part length indicator could be less or equal to 300 (ie: part B). typedef struct parsedPacket_struct { char partA[2];int len_partA; char partB[300];int len_partB; char partC[2];int len_partC; }parsedPacket; The problem here is that I am wasting memory, because each structure should copy the packet content to each the structure, is there a way to only save the base address of each part and still using the len_partX.

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