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  • Need a refresher course on property access...

    - by Code Sherpa
    Hi. I need help with accessing class properties within a given class. For example, take the below class: public partial class Account { private Profile _profile; private Email _email; private HostInfo _hostInfo; public Profile Profile { get { return _profile; } set { _profile = value; } } public Email Email { get { return _email; } set { _email = value; } } public HostInfo HostInfo { get { return _hostInfo; } set { _hostInfo = value; } } In the class "Account" exists a bunch of class properties such as Email or Profile. Now, when I want to access those properties at run-time, I do something like this (for Email): _accountRepository = ObjectFactory.GetInstance<IAccountRepository>(); string username = Cryptography.Decrypt(_webContext.UserNameToVerify, "verify"); Account account = _accountRepository.GetAccountByUserName(username); if(account != null) { account.Email.IsConfirmed = true; But, I get "Object reference not set..." for account.Email... Why is that? How do I access Account such that account.Email, account.Profile, and so on returns the correct data for a given AccountId or UserName. Here is a method that returns Account: public Account GetAccountByUserName(string userName) { Account account = null; using (MyDataContext dc = _conn.GetContext()) { try { account = (from a in dc.Accounts where a.UserName == userName select a).FirstOrDefault(); } catch { //oops } } return account; } The above works but when I try: account = (from a in dc.Accounts join em in dc.Emails on a.AccountId equals em.AccountId join p in dc.Profiles on em.AccountId equals p.AccountId where a.UserName == userName select a).FirstOrDefault(); I am still getting object reference exceptions for my Email and Profile properties. Is this simply a SQL problem or is there something else I need to be doing to be able to fully access all the properties within my Account class? Thanks!

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  • How to marshal an object and its content (also objects)

    - by Waldo Spek
    I have a question for which I suspect the answer is a bit complex. At this moment I am programming a DLL (class library) in C#. This DLL uses a 3rd party library and therefore deals with 3rd party objects of which I do not have the source code. Now I am planning to create another DLL, which is going to be used in a later stadium in my application. This second DLL should use the 3rd party objects (with corresponding object states) created by the first DLL. Luckily the 3rd party objects extend the MarshalByRefObject class. I can marshal the objects using System.Runtime.Remoting.Marshal(...). I then serialize the objects using a BinaryFormatter and store the objects as a byte[] array. All goes well. I can deserialize and unmarshal in a the opposite way and end up with my original 3rd party objects...so it appears... Nevertheless, when calling methods on my 3rd party deserialized objects I get object internal exceptions. Normally these methods return other 3rd party objects, but (obviously - I guess) now these objects are missing because they weren't serialized. Now my global question: how would I go about marshalling/serializing all the objects which my 3rd party objects reference...and cascade down the "reference tree" to obtain a full and complete serialized object? Right now my guess is to preprocess: obtain all the objects and build my own custom object and serialize it. But I'm hoping there is some other way...

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  • using yield in C# like I would in Ruby

    - by Sarah Vessels
    Besides just using yield for iterators in Ruby, I also use it to pass control briefly back to the caller before resuming control in the called method. What I want to do in C# is similar. In a test class, I want to get a connection instance, create another variable instance that uses that connection, then pass the variable to the calling method so it can be fiddled with. I then want control to return to the called method so that the connection can be disposed. I guess I'm wanting a block/closure like in Ruby. Here's the general idea: private static MyThing getThing() { using (var connection = new Connection()) { yield return new MyThing(connection); } } [TestMethod] public void MyTest1() { // call getThing(), use yielded MyThing, control returns to getThing() // for disposal } [TestMethod] public void MyTest2() { // call getThing(), use yielded MyThing, control returns to getThing() // for disposal } ... This doesn't work in C#; ReSharper tells me that the body of getThing cannot be an iterator block because MyThing is not an iterator interface type. That's definitely true, but I don't want to iterate through some list. I'm guessing I shouldn't use yield if I'm not working with iterators. Any idea how I can achieve this block/closure thing in C# so I don't have to wrap my code in MyTest1, MyTest2, ... with the code in getThing()'s body?

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  • How do I check to see if a scalar has a compiled regex in it with Perl?

    - by Robert P
    Let's say I have a subroutine/method that a user can call to test some data that (as an example) might look like this: sub test_output { my ($self, $test) = @_; my $output = $self->long_process_to_get_data(); if ($output =~ /\Q$test/) { $self->assert_something(); } else { $self->do_something_else(); } } Normally, $test is a string, which we're looking for anywhere in the output. This was an interface put together to make calling it very easy. However, we've found that sometimes, a straight string is problematic - for example, a large, possibly varying number of spaces...a pattern, if you will. Thus, I'd like to let them pass in a regex as an option. I could just do: $output =~ $test if I could assume that it's always a regex, but ah, but the backwards compatibility! If they pass in a string, it still needs to test it like a raw string. So in that case, I'll need to test to see if $test is a regex. Is there any good facility for detecting whether or not a scalar has a compiled regex in it?

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  • WCF service not working after program update

    - by Boesj
    I have recently added a WCF service reference to my program. When I perform a clean install of this program, everything seems to work as expected. But, when I install the program on a client which already has a previous version (without the new service reference) installed, I get a exception telling me the default endpoint for this particular service could not be found. It seems that the appname.exe.config is not being updated with the new endpoint settings. Is there any reason for this and how can I force the installer to overwrite the config file? I'm using the default Visual Studio 2008 installer project with RemovePreviousVersions set to True. Update: My program encrypts the settings section after the first run with the following code Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None); ConfigurationSection section = config.GetSection(sectionKey); if (section != null) { if (!section.SectionInformation.IsProtected) { if (!section.ElementInformation.IsLocked) { section.SectionInformation.ProtectSection("DataProtectionConfigurationProvider"); section.SectionInformation.ForceSave = true; config.Save(ConfigurationSaveMode.Full); } } } When I do not run the program before installing the new version the app.config gets updated.

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  • CXF code first service, WSDL generation; soap:address changes?

    - by jcalvert
    I have a simple Java interface/implementation I am exposing via CXF. I have a jaxws element in my Spring configuration file like this: <jaxws:endpoint id="managementServiceJaxws" implementor="#managementService" address="/jaxws/ManagementService" > </jaxws:endpoint> It generates the WSDL from my annotated interface and exposes the service. Then when I hit http://myhostname/cxf/jaxws/ManagementService?wsdl I get a lovely WSDL. At the bottom in the wsdl:service element, I'll see <soap:address location="http://myhostname/cxf/jaxws/ManagementService"/> However, some time a day or so later, with no application restart, hitting that same url produces: This causes a number of problems, but what I really want is to fix it. Right now, there's a particular client to the webservice that sets the endpoint to localhost; because it runs on the same machine. Is it possible the wsdl is getting regenerated and cached and then exposing the 'localhost' version? In part I don't know the exact mechanism by which one goes from a ?wsdl request in CXF to the response. It seems almost certain that it's retrieving some cached version, given that it's supposed to be determining the address by asking the servletcontainer (Jetty). For reference I know a stopgap solution is using the hostname on the client and making sure an alias in place so that it goes over the loopback. EDIT: For reference, I confirmed that if I bring my application up and first hit it over localhost, then querying for the wsdl via the hostname shows the address as localhost. Conversely, first hitting it over the hostname causes localhost requests to show the hostname. So obviously something is getting cached here.

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  • Packages name conflicting with getters and setters?

    - by MrKishi
    Hello, folks. So, I've came across this compilation error a while ago.. As there's an easy fix and I didn't find anything relevant at the time, I eventually let it go. I just remembered it and I'm now wondering if this is really part of the language grammar (which I highly doubt) or if it's a compiler bug. I'm being purely curious about this -- it doesn't really affect development, but it would be nice to see if any of you have seen this already. package view { import flash.display.Sprite; public class Main extends Sprite { private var _view:Sprite = new Sprite(); public function Main() { this.test(); } private function test():void { trace(this.view.x, this.view.y); //1178: Attempted access of inaccessible property x through a reference with static type view:Main. //1178: Attempted access of inaccessible property y through a reference with static type view:Main. //Note that I got this due to the package name. //It runs just fine if I rename the package or getter. } public function get view():Sprite { return this._view; } } }

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  • Type of member is not CLS-compliant

    - by John Galt
    Using Visual Studio 2008 and VB.Net: I have a working web app that uses an ASMX web service which is compiled into its separate assembly. I have another class library project compiled as a separate assembly that serves as a proxy to this web service. This all seems to work at runtime but I am getting this warning at compile time which I don't understand and would like to fix: Type of member 'wsZipeee' is not CLS-compliant I have dozens of webforms in the main project that reference the proxy class with no compile time complaints as this snippet shows: Imports System.Data Partial Class frmZipeee Inherits System.Web.UI.Page Public wsZipeee As New ProxyZipeeeService.WSZipeee.Zipeee Dim dsStandardMsg As DataSet Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load And yet I have one webform (also in the root of the main project) which gives me the "not CLS-compliant" message but yet attempts to reference the proxy class just like the other ASPX files. I get the compile time warning on the line annoted by me with 'ERROR here.. Imports System.Data Partial Class frmHome Inherits System.Web.UI.Page Public wsZipeee As New ProxyZipeeeService.WSZipeee.Zipeee ERROR here Dim dsStandardMsg As DataSet Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load This makes no sense to me. The file with the warning is called frmHome.aspx.vb; all others in the project declare things the same way and have no warning. BTW, the webservice itself returns standard datatypes: integer, string, and dataset.

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  • PHP DELETE immediately after select

    - by teehoo
    I have a PHP server script that SELECTs some data from a MySQL database. As soon as I have the result from mysql_query and mysql_fetch_assoc stored in my own local variables, I want to delete the row I just selected. The problem with this approach is that it seems that PHP has done pass-by-reference to my local variables instead of pass-by-value, and my local variables become undefined after the delete command. Is there anyway to get around this? Here is my code: $query="SELECT id, peerID, name FROM names WHERE peer = $userID AND docID = '$docID' AND seqNo = $nid"; $result = mysql_query($query); if (!$result) self::logError("FAIL:1 getUsersNamesUpdate() query: ".$query."\n"); if (mysql_num_rows($result) == 0) return array(); $row = mysql_fetch_assoc($result); $result = array(); $result["id"] = $row["id"]; $result["peerID"] = $row["peerID"]; $result["name"] = $row["name"]; $query="DELETE FROM names WHERE id = $result[id];"; $result = mysql_query($query); if (!$result) self::logError("FAIL:2 getUsersNamesUpdate() query: ".$query."\n"); return $result;

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  • Creating a function to grab data from an Oracle database (array by ID)

    - by Nick
    I'm trying to create a function that will simply allow me to pass an SQL statement into it, and it will generate an array based on a unique ID I pass it: function oracleGetGata($query, $id="id") { global $conn; $sql = OCI_Parse($conn, $query); OCI_Execute($sql); OCI_Fetch_All($sql, $results, null, null, OCI_FETCHSTATEMENT_BY_ROW); return $results; }   For example I'd like this query $array = oracleGetData('select * from table') to return something like: [1] => Array ( [Title] => Title 1 [Description] => Description 1 ) [2] => Array ( [Title] => Title 2 [Description] => Description 2 ) [3] => Array ( [Title] => Title 3 [Description] => Description 3 )   Rather than what it's returning at the moment: [0] => Array ( [ID] => 3 [TITLE] => Title 3 [DESCRIPTION] => Description 3 ) [1] => Array ( [ID] => 1 [TITLE] => Title 1 [DESCRIPTION] => Description 1 ) [2] => Array ( [ID] => 2 [TITLE] => Title 2 [DESCRIPTION] => Description 2 )   I'd really appreciate any help with this, as the function would save me lots of time! Thank you.

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  • Overlay an image over video using OpenGL ES shaders

    - by BlueVoodoo
    I am trying to understand the basic concepts of OpenGL. A week into it, I am still far from there. Once I am in glsl, I know what to do but I find getting there is the tricky bit. I am currently able to pass in video pixels which I manipulate and present. I have then been trying to add still image as an overlay. This is where I get lost. My end goal is to end up in the same fragment shader with pixel data from both my video and my still image. I imagine this means I need two textures and pass on two pixel buffers. I am currently passing the video pixels like this: glGenTextures(1, &textures[0]); //target, texture glBindTexture(GL_TEXTURE_2D, textures[0]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, buffer); Would I then repeat this process on textures[1] with the second buffer from the image? If so, do I then bind both GL_TEXTURE0 and GL_TEXTURE1? ...and would my shader look something like this? uniform sampler2D videoData; uniform sampler2D imageData; once I am in the shader? It seems no matter what combination I try, image and video always ends up being just video data in both these. Sorry for the many questions merged in here, just want to clear my many assumptions and move on. To clarify the question a bit, what do I need to do to add pixels from a still image in the process described? ("easy to understand" sample code or any types of hints would be appreciated).

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  • Advice on Minimizing Stored Procedure Parameters

    - by RPM1984
    Hi Guys, I have an ASP.NET MVC Web Application that interacts with a SQL Server 2008 database via Entity Framework 4.0. On a particular page, i call a stored procedure in order to pull back some results based on selections on the UI. Now, the UI has around 20 different input selections, ranging from a textbox, dropdown list, checkboxes, etc. Each of those inputs are "grouped" into logical sections. Example: Search box : "Foo" Checkbox A1: ticked, Checkbox A2: unticked Dropdown A: option 3 selected Checkbox B1: ticked, Checkbox B2: ticked, Checkbox B3: unticked So i need to call the SPROC like this: exec SearchPage_FindResults @SearchQuery = 'Foo', @IncludeA1 = 1, @IncludeA2 = 0, @DropDownSelection = 3, @IncludeB1 = 1, @IncludeB2 = 1, @IncludeB3 = 0 The UI is not too important to this question - just wanted to give some perspective. Essentially, i'm pulling back results for a search query, filtering these results based on a bunch of (optional) selections a user can filter on. Now, My questions/queries: What's the best way to pass these parameters to the stored procedure? Are there any tricks/new ways (e.g SQL Server 2008) to do this? Special "table" parameters/arrays - can we pass through User-Defined-Types? Keep in mind im using Entity Framework 4.0 - but could always use classic ADO.NET for this if required. What about XML? What are the serialization/de-serialization costs here? Is it worth it? How about a parameter for each logical section? Comma-seperated perhaps? Just thinking out loud. This page is particulary important from a user point of view, and needs to perform really well. The stored procedure is already heavy in logic, so i want to minimize the performance implications - so keep that in mind. With that said - what is the best approach here?

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  • Problem with SqlLite database in Qt SDK 1.0.2

    - by Risino
    Hi I have a problem with SqlLite database. Here is my code: void incomeDialog::on_add_pushButton_clicked() { int a = ui->income_lineEdit->text().toInt(); int b = ui->other_lineEdit->text().toInt(); int c = (a+b); db = QSqlDatabase::addDatabase("QSQLITE"); db.setDatabaseName("money.db"); QSqlQuery query(db); query.exec("create table Income" "(Month TEXT, Payment NUMBER, Other NUMBER, Together NUMBER)"); query.prepare("INSERT INTO Income values (?,?,?,?)"); query.addBindValue(ui->comboBox->currentText()); query.addBindValue(ui->income_lineEdit->text().toInt()); query.addBindValue(ui->other_lineEdit->text().toInt()); query.addBindValue(c); query.exec(); } I use qt sdk 1.0.2. After building shows errors: Undefined reference to 'QSqlDatabase::addDatabase(QString const&, QString const&)... all errors is similar (Undefined reference to 'QSqlDatabase:: Do you have any idea how to repair it?

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  • c# template member functions

    - by user3730583
    How can I define a template member function in C# For instance I will fill any collection which supports an Add(...) member function, please check out the sample code below public class CInternalCollection { public static void ExternalCollectionTryOne<T<int>>(ref T<int> ext_col, int para_selection = 0) { foreach (int int_value in m_int_col) { if (int_value > para_selection) ext_col.Add(int_value); } } public static void ExternalCollectionTryTwo<T>(ref T ext_col, int para_selection = 0) { foreach (int int_value in m_int_col) { if (int_value > para_selection) ext_col.Add(int_value); } } static int[] m_int_col = { 0, -1, -3, 5, 7, -8 }; } The ExternalCollectionTryOne<...(...) would be the preferred kind, because the int type can be explicit defined, but results in an error: Type parameter declaration must be an identifier not a type The type or namespace name 'T' could not be found (are you missing a using directive or an assembly reference?) The ExternalCollectionTryTwo<...(...) results in an error: 'T' does not contain a definition for 'Add' and no extension method 'Add' accepting a first argument of type 'T' could be found (are you missing a using directive or an assembly reference?)... I hope the problem is clear – any suggestions? ----------------------------- edit -------------------------- The answers with the interface ICollection<.. without a template member works fine and thanks all for this hint, but I still cannot define successfully a member template(generic) function So a more simpler example ... how can I define this public class CAddCollectionValues { public static void AddInt<T>(ref T number, int selection) { T new_T = new T(); //this line is just an easy demonstration to get a compile error with type T foreach (int i_value in m_int_col) { if (i_value > selection) number += i_value; //again the type T cannot be used } } static int[] m_int_col = { 0, -1, -3, 5, 7, -8 }; }

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  • Creating a C++ DLL and then using it in C#

    - by Major
    Ok I'm trying to make a C++ DLL that I can then call and reference in a c# App. I've already made a simple dll using the numberous guides out there, however when I try to reference it in the C# app I get the error Unable to load DLL 'SDES.dll': The specified module could not be found. The code for the program is as follows (bear with me I'm going to include all the files) //These are the DLL Files. ifndef TestDLL_H define TestDLL_H extern "C" { // Returns a + b __declspec(dllexport) double Add(double a, double b); // Returns a - b __declspec(dllexport) double Subtract(double a, double b); // Returns a * b __declspec(dllexport) double Multiply(double a, double b); // Returns a / b // Throws DivideByZeroException if b is 0 __declspec(dllexport) double Divide(double a, double b); } endif //.cpp include "test.h" include using namespace std; extern double __cdecl Add(double a, double b) { return a + b; } extern double __cdecl Subtract(double a, double b) { return a - b; } extern double __cdecl Multiply(double a, double b) { return a * b; } extern double __cdecl Divide(double a, double b) { if (b == 0) { throw new invalid_argument("b cannot be zero!"); } return a / b; } //C# Program using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.InteropServices; namespace ConsoleApplication1 { class Program { [DllImport("SDES.dll")] public static extern void SimulateGameDLL(int a, int b); static void Main(string[] args) { SimulateGameDLL(1, 2); //Error here... } } } Anyone have any idea's what I may be missing in my program? Let me know if I missed some code or if you have any questions.

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  • javascript error of unterminated string

    - by OM The Eternity
    I want pass a parameter of javascript functiona which is a string. This javascript function is a hintbox on mousehover.. and the string i am using is like this: Hemmed Finish: Every side/edge (1/2" to 2") of the banner are folded and glued (special vinyl solution) or heat pressed. This is the most common and best finish option. Stitched Finish: Every side/edge (1" to 2") of the banner are folded in the back and stitched/sewed with white thread. This is not a common option as thread can be seen on the banner. Now in the hintbox on mousehover the above given text has to be display as it is displayed above along with the paragraph break.. But when i pass the above as parameter in that function along with appending some backslashes to recognise some punctuation, iots till gives me javascript error of unterminated string... I am doing this: onMouseover="showhint('Hemmed Finish\: Every side/edge \(1/2\'\' to 2\'\'\) of the banner are folded and glued \(special vinyl solution\) or heat pressed. This is the most common and best finish option.Stitched Finish\: Every side/edge \(1\'\' to 2\'\'\) of the banner are folded in the back and stitched/sewed with white thread. This is not a common option as thread can be seen on the banner', this, event, '250px')" pls could u help me in rectifying the issue...

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  • Javascript (using jQuery) in a large Project... organization, passing data, private method, etc.

    - by gaoshan88
    I'm working on a large project that is organized like so: Multiple javascript files are included as needed and most code is wrapped in anonymous functions... // wutang.js //Included Files Go Here // Public stuff var MethodMan; // Private stuff (function() { var someVar1; MethodMan = function(){...}; var APrivateMethod = function(){...}; $(function(){ //jquery page load stuff here $('#meh').click(APrivateMethod); }); })(); I'm wondering about a few things here. Assuming that there are a number of these files included on a page, what has access to what and what is the best way to pass data between the files? For example, I assume that MethodMan() can be accessed by anything on any included page. It is public, yes? var someVar1 is only accessible to the methods inside that particular anonymous function and nowhere else, yes? Also true of var APrivateMethod(), yes? What if I want APrivateMethod() to make something available to some other method in a different anonymous wrapped method in a different included page. What's the best way to pass data between these private, anonymous functions on different included pages? Do I simply have to make whatever I want to use between them public? How about if I want to minimize global variables? What about the following: var PootyTang = function(){ someVar1 = $('#someid').text(); //some stuff }; and in another included file used by that same page I have: var TangyPoot = function(){ someVar1 = $('#someid').text(); //some completely different stuff }; What's the best way to share the value of someVar1 across these anonymous (they are wrapped as the first example) functions?

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  • Updating a composite primary key

    - by VBCSharp
    I am struggling with the philosophical discussions about whether or not to use composite primary keys on my SQL Server database. I have always used the surrogate keys in the past and I am challenging myself by leaving my comfort zone to try something different. I have read many discussion but can't come to any kind of solution yet. The struggle I am having is when I have to update a record with the composite PK. For example, the record in questions is like this: ContactID, RoleID, EffectiveDate, TerminationDT. The PK in this case is the ContactID, RoleID, and EffectiveDate. TerminationDT can be null. If in my UI, the user changes the RoleID and then I need to update the record. Using the surrogate key I can do an Update Table Set RoleID = 1 WHERE surrogateID = Z. However, using the Composite Key way, once one of the fields in the composite key changes I have no way to reference the old record to update it without now maintaining somewhere in the UI a reference to the old values. I do not bind datasources in my UI. I open a connection, get the data and store it in a bucket, then close the connection. What are everyone's opinions? Thanks.

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  • What else I must do allow my method to handle any type of objects

    - by NewHelpNeeder
    So to allow any type object I must use generics in my code. I have rewrote this method to do so, but then when I create an object, for example Milk, it won't let me pass it to my method. Ether there's something wrong with my generic revision, or Milk object I created is not good. How should I pass my object correctly and add it to linked list? This is a method that causes error when I insert an item: public void insertFirst(T dd) // insert at front of list { Link newLink = new Link(dd); // make new link if( isEmpty() ) // if empty list, last = newLink; // newLink <-- last else first.previous = newLink; // newLink <-- old first newLink.next = first; // newLink --> old first first = newLink; // first --> newLink } This is my class I try to insert into linked list: class Milk { String brand; double size; double price; Milk(String a, double b, double c) { brand = a; size = b; price = c; } } This is test method to insert the data: public static void main(String[] args) { // make a new list DoublyLinkedList theList = new DoublyLinkedList(); // this causes: // The method insertFirst(Comparable) in the type DoublyLinkedList is not applicable for the arguments (Milk) theList.insertFirst(new Milk("brand", 1, 2)); // insert at front theList.displayForward(); // display list forward theList.displayBackward(); // display list backward } // end main() } // end class DoublyLinkedApp Declarations: class Link<T extends Comparable<T>> {} class DoublyLinkedList<T extends Comparable<T>> {}

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  • What wrapper class in C++ should I use for automated resource management?

    - by Vilx-
    I'm a C++ amateur. I'm writing some Win32 API code and there are handles and weirdly compositely allocated objects aplenty. So I was wondering - is there some wrapper class that would make resource management easier? For example, when I want to load some data I open a file with CreateFile() and get a HANDLE. When I'm done with it, I should call CloseHandle() on it. But for any reasonably complex loading function there will be dozens of possible exit points, not to mention exceptions. So it would be great if I could wrap the handle in some kind of wrapper class which would automatically call CloseHandle() once execution left the scope. Even better - it could do some reference counting so I can pass it around in and out of other functions, and it would release the resource only when the last reference left scope. The concept is simple - but is there something like that in the standard library? I'm using Visual Studio 2008, by the way, and I don't want to attach a 3rd party framework like Boost or something.

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  • Why does this code sample produce a memory leak?

    - by citronas
    In the university we were given the following code sample and we were being told, that there is a memory leak when running this code. The sample should demonstrate that this is a situation where the garbage collector can't work. As far as my object oriented programming goes, the only codeline able to create a memory leak would be items=Arrays.copyOf(items,2 * size+1); The documentation says, that the elements are copied. Does that mean the reference is copied (and therefore another entry on the heap is created) or the object itself is being copied? As far as I know, Object and therefore Object[] are implemented as a reference type. So assigning a new value to 'items' would allow the garbage collector to find that the old 'item' is no longer referenced and can therefore be collected. In my eyes, this the codesample does not produce a memory leak. Could somebody prove me wrong? =) import java.util.Arrays; public class Foo { private Object[] items; private int size=0; private static final int ISIZE=10; public Foo() { items= new Object[ISIZE]; } public void push(final Object o){ checkSize(); items[size++]=o; } public Object pop(){ if (size==0) throw new ///... return items[--size]; } private void checkSize(){ if (items.length==size){ items=Arrays.copyOf(items,2 * size+1); } } }

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  • 2 dimensional arrays passed to a function in c++

    - by John Marcus
    I'm working on doing calculations in a two dimensional array but keep getting a nasty error. i call the function by : if(checkArray(array)) and try to pass it in like this: bool checkArray(double array[][10]) //or double *array[][10] to no avail the error is error: cannot convert ‘double ()[(((unsigned int)(((int)n) + -0x00000000000000001)) + 1)]’ to ‘double’ for argument ‘1’ to ‘bool checkArray(double*)’ code snippet //array declaration int n = 10; double array[n][n]; //function call to pass in array while(f != 25) { cout<<endl; cout<<endl; if(checkArray(array)) //this is the line of the error { cout<<"EXIT EXIT EXIT"<<endl; } f++; } //function declaration bool checkArray(double *array)//, double newArray[][10]) { double length = sizeof(array); for(int i = 0; i < length; i++) for(int j = 0; j < length;j++) { double temp = array[i][j]; } }

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  • Inversion of control domain objects construction problem

    - by Andrey
    Hello! As I understand IoC-container is helpful in creation of application-level objects like services and factories. But domain-level objects should be created manually. Spring's manual tells us: "Typically one does not configure fine-grained domain objects in the container, because it is usually the responsibility of DAOs and business logic to create/load domain objects." Well. But what if my domain "fine-grained" object depends on some application-level object. For example I have an UserViewer(User user, UserConstants constants) class. There user is domain object which cannot be injected, but UserViewer also needs UserConstants which is high-level object injected by IoC-container. I want to inject UserConstants from the IoC-container, but I also need a transient runtime parameter User here. What is wrong with the design? Thanks in advance! UPDATE It seems I was not precise enough with my question. What I really need is an example how to do this: create instance of class UserViewer(User user, UserService service), where user is passed as the parameter and service is injected from IoC. If I inject UserViewer viewer then how do I pass user to it? If I create UserViewer viewer manually then how do I pass service to it?

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  • Why do we need Audit Columns in Database Tables?

    - by Software Enthusiastic
    Hi I have seen many database designs having following audit columns on all the tables... Created By Create DateTime Updated By Upldated DateTime From one perspective I see tables from the following view... Entity Tables: Good candidate for Audit columns) Reference Tables: Audit columns may or may not required. In some case last update information is not at all required because record is never going to be modified.) Reference Data Tables Like Country Names, Entity State etc... Audit columns may not required because these information is created only during system installation time, and never going to be changed. I have seen many designers blindly put all audit columns to all tables, is this practice good, if yes what could be the reason... I just want to know because to me it seems illogical. It is difficult for me to figure out why do they design their db this way? I am not saying they are wrong or right, just want to know the WHY? You can also suggest me, if there is an alternative auditing patter or solution available... Thanks and Regards

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  • NHibernate class referencing discriminator based subclass

    - by Rich
    I have a generic class Lookup which contains code/value properties. The table PK is category/code. There are subclasses for each category of lookup, and I've set the discriminator column in the base class and its value in the subclass. See example below (only key pieces shown): public class Lookup { public string Category; public string Code; public string Description; } public class LookupClassMap { CompositeId() .KeyProperty(x = x.Category, "CATEGORY_ID") .KeyProperty(x = x.Code, "CODE_ID"); DiscriminateSubclassesBasedOnColumn("CATEGORY_ID"); } public class MaritalStatus: Lookup {} public class MartialStatusClassMap: SubclassMap { DiscriminatorValue(13); } This all works. Here's the problem. When a class has a property of type MaritalStatus, I create a reference based on the contained code ID column ("MARITAL_STATUS_CODE_ID"). NHibernate doesn't like it because I didn't map both primary key columns (Category ID & Code ID). But with the Reference being of type MaritalStatus, NHibernate should already know what the value of the category ID is going to be, because of the discriminator value. What am I missing?

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