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  • General ORM design question

    - by Calvin
    Suppose you have 2 classes, Person and Rabbit. A person can do a number of things to a rabbit, s/he can either feed it, buy it and become its owner, or give it away. A rabbit can have none or at most 1 owner at a time. And if it is not fed for a while, it may die. Class Person { Void Feed(Rabbit r); Void Buy(Rabbit r); Void Giveaway(Person p, Rabbit r); Rabbit[] rabbits; } Class Rabbit { Bool IsAlive(); Person pwner; } There are a couple of observations from the domain model: Person and Rabbit can have references to each other Any actions on 1 object can also change the state of the other object Even if no explicit actions are invoked, there can still be a change of state in the objects (e.g. Rabbit can be starved to death, and that causes it to be removed from the Person.rabbits array) As DDD is concerned, I think the correct approach is to synchronize all calls that may change the states in the domain model. For instance, if a Person buys a Rabbit, s/he would need to acquire a lock in Person to make a change to the rabbits array AND also another lock in Rabbit to change its owner before releasing the first one. This would prevent a race condition where 2 Persons claim to be the owner of the little Rabbit. The other approach is to let the database to handle all these synchronizations. Who makes the first call wins, but then the DB needs to have some kind of business logics to figure out if it is a valid transaction (e.g. if a Rabbit already has an owner, it cannot change its owner unless the Person gives it away). There are both pros/cons in either approach, and I’d expect the “best” solution would be somewhere in-between. How would you do it in real life? What’s your take and experience? Also, is it a valid concern that there can be another race condition the domain model has committed its change but before it is fully committed in the database? And for the 3rd observation (i.e. state change due to time factor). How will you do it?

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  • LINQ VB.NET variable not found when looping through grouped query

    - by Ed Sneller
    I'm trying to do the following LINQ grouping, which works in the debugger (the results are populated in the GroupedOrders object. But VS 2008 gives me the following error at design time... Name 'x' is not declared Dim GroupedOrders = (From m In thisConsultant.orders _ Group m By Key = m.commCode Into Group _ Select commCode = Key, orders = Group) For Each x In GroupedOrders Next VS 2008 gives me the following error,

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  • Dreamweaver javascript code hints

    - by xdevel2000
    I'd to use DW cs 4 but before to buy I want to test javascript code hints. However that feature doesn't work at all. I have an external .js library and then into an html file I load it but when I type functions or object by name nothing happen. Any idea?

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  • How can I create a Base64-Encoded string from an GDI+ Image in C++?

    - by Schnapple
    I asked a question recently, How can I create an Image in GDI+ from a Base64-Encoded string in C++?, which got a response that led me to the answer. Now I need to do the opposite - I have an Image in GDI+ whose image data I need to turn into a Base64-Encoded string. Due to its nature, it's not straightforward. The crux of the issue is that an Image in GDI+ can save out its data to either a file or an IStream*. I don't want to save to a file, so I need to use the resulting stream. Problem is, this is where my knowledge breaks down. This first part is what I figured out in the other question // Initialize GDI+. GdiplusStartupInput gdiplusStartupInput; ULONG_PTR gdiplusToken; GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL); // I have this decode function from elsewhere std::string decodedImage = base64_decode(Base64EncodedImage); // Allocate the space for the stream DWORD imageSize = decodedImage.length(); HGLOBAL hMem = ::GlobalAlloc(GMEM_MOVEABLE, imageSize); LPVOID pImage = ::GlobalLock(hMem); memcpy(pImage, decodedImage.c_str(), imageSize); // Create the stream IStream* pStream = NULL; ::CreateStreamOnHGlobal(hMem, FALSE, &pStream); // Create the image from the stream Image image(pStream); // Cleanup pStream->Release(); GlobalUnlock(hMem); GlobalFree(hMem); (Base64 code) And now I'm going to perform an operation on the resulting image, in this case rotating it, and now I want the Base64-equivalent string when I'm done. // Perform operation (rotate) image.RotateFlip(Gdiplus::Rotate180FlipNone); IStream* oStream = NULL; CLSID tiffClsid; GetEncoderClsid(L"image/tiff", &tiffClsid); // Function defined elsewhere image.Save(oStream, &tiffClsid); // And here's where I'm stumped. (GetEncoderClsid) So what I wind up with at the end is an IStream* object. But here's where both my knowledge and Google break down for me. IStream shouldn't be an object itself, it's an interface for other types of streams. I'd go down the road from getting string-Image in reverse, but I don't know how to determine the size of the stream, which appears to be key to that route. How can I go from an IStream* to a string (which I will then Base64-Encode)? Or is there a much better way to go from a GDI+ Image to a string?

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  • What Controller/Action will this go to?

    - by rkrauter
    Assume this is the first route entry: routes.MapRoute( "myRoute", "employees/{city}/{pageNumber}", new { controller="Employees", action = "List", pageNumber = 1 } ); If I make the following request employees/london/2 it gets matched to the following action method: public ActionResult List(string city) {} How did that happen? I did not specify "city" in my object defaults: new { controller="Employees", action = "List", pageNumber = 1 } Please explain. Thanks!

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  • how to update only the updated rows in gridview?

    - by user603007
    what is the handiest way to update only the updated rows (only the checkbox column) in this gridview? what is a handy way to check wether the row was updated? c# public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { List<customer> listCustomer = new List<customer>(); customer cust1 = new customer(){name="fred",email="[email protected]",jobless="true"}; customer cust2 = new customer(){name="mark",email="[email protected]",jobless="false"}; listCustomer.Add(cust1); listCustomer.Add(cust2); GridView1.DataSource=listCustomer; GridView1.DataBind(); } } protected void btnUpdate_Click1(object sender, EventArgs e) { foreach (GridViewRow rw in GridView1.Rows) { CheckBox thiscontrol = (CheckBox)rw.Cells[0].FindControl("cb"); var ch = thiscontrol.Checked; //only update the updated rows? } } public class customer { public string name { get; set; } public string email { get; set; } public string jobless { get; set; } } html <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="gridviewUpdate._Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> </head> <body> <form id="form1" runat="server"> <div> <asp:GridView ID="GridView1" AutoGenerateColumns="false" runat="server"> <Columns> <asp:TemplateField> <ItemTemplate> <asp:CheckBox ID="jobless" runat="server" Checked='<%# Eval("jobless").ToString().Equals("true") %>' /> </ItemTemplate> </asp:TemplateField> <asp:BoundField DataField="email" /> <asp:BoundField DataField="name" /> </Columns> </asp:GridView> </div>

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  • Is PHP still basically Procedural Overall?

    - by coffeeaddict
    I know PHP 5 has some object oriented similarities but it's not a true OOP environment still right? Also does it have a true compiler? I see compiling of scripts which still means procedural. I assume it's not a real compiler in that any PHP compilers out there do not create assemblies?

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  • Asp.net MVC Ajax form that return Json to a javascript method.

    - by Diego Correa
    Hello guys, I have an ajax form that saves a object in the database then return a Message like this: return Json(new {Message = "Message!"}, JsonRequestBehavior.AllowGet); We are ok here, but I don't know HOW I'll get this result in the view to display in a jQuery modal. My ajax form is like the following and I want to get the result on the OnSuccess method: <%using (Ajax.BeginForm("Form", "Controller", new AjaxOptions() { OnSuccess = "MethodThatIWantToGetTheJson" })) Any ideas?

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  • Spring aspectj jar not configured correctly

    - by newguy
    I am getting this error when I tried to use a JPA object created by Roo. Entity manager has not been injected (is the Spring Aspects JAR configured as an AJC/AJDT aspects library?) I have followed some online advice to add the spring-aspects.jar to aspectj path in Eclipse but I still get this error. Does anyone know how to solve this? The environment I am using is Spring 3.0.5, Hibernate 3.6 and JBoss 6.0.0.Final.

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  • Set Masterpage from Global.asax in ASP.NET

    - by StefanE
    Hi, I want to set the Masterpage property in Global.asax. This is what I have done but I get a NullReferenceException on the first line. Any ideas how to do this? protected void Application_PreSendRequestContent(Object sender, EventArgs e) { System.Web.UI.Page page = System.Web.HttpContext.Current.Handler as System.Web.UI.Page; if (Session["lang"] == "eng") { page.MasterPageFile = "SideMasterPageEng.master"; } }

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  • Effect of 'myObj = [[[[MyClass alloc] init] autorelease] retain];'?

    - by filipe
    I've just downloaded the Facebook iOS SDK and I noticed that in the sample code that comes with the SDK whenever it creates an instance of the Facebook class it does it like this: _facebook = [[[[Facebook alloc] init] autorelease] retain]; where _facebook is a member variable of the calling object (i.e. not a local variable). Can anyone explain exactly what's the point of autoreleasing and then retaining it?

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  • Where are SSIS Packages Saved?

    - by Chris
    I right clicked on a Database in the object explorer of SQL Server 2008 Management Studio. I went to Tasks Import Data, and imported some data from a flat text file, opting to save the package on the server. Now how the heck do I get to the package to edit or run it again? Where in SQL Server Management Studio do I go? I've expanded everything and I can't find it. It's driving me nuts.

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  • .NET Extension Objects with XSLT -- how to iterate over a collection?

    - by Pandincus
    Help me, Stackoverflow! I have a simple .NET 3.5 console app that reads some data and sends emails. I'm representing the email format in an XSLT stylesheet so that we can easily change the wording of the email without needing to recompile the app. We're using Extension Objects to pass data to the XSLT when we apply the transformation: <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl" xmlns:EmailNotification="ext:EmailNotification"> -- this way, we can have statements like: <p> Dear <xsl:value-of select="EmailNotification:get_FullName()" />: </p> The above works fine. I pass the object via code like this (some irrelevant code omitted for brevity): // purely an example structure public struct EmailNotification { public string FullName { get; set; } } // Somewhere in some method ... var notification = new Notification("John Smith"); // ... XsltArgumentList xslArgs = new XsltArgumentList(); xslArgs.AddExtensionObject("ext:EmailNotification", notification); // ... // The part where it breaks! (This is where we do the transformation) xslt.Transform(fakeXMLDocument.CreateNavigator(), xslArgs, XmlWriter.Create(transformedXMLString)); So, all of the above code works. However, I wanted to get a little fancy (always my downfall) and pass a collection, so that I could do something like this: <p>The following accounts need to be verified:</p> <xsl:for-each select="EmailNotification:get_SomeCollection()"> <ul> <li> <xsl:value-of select="@SomeAttribute" /> </li> </ul> <xsl:for-each> When I pass the collection in the extension object and attempt to transform, I get the following error: "Extension function parameters or return values which have Clr type 'String[]' are not supported." or List, or IEnumerable, or whatever I try to pass in. So, my questions are: How can I pass in a collection to my XSLT? What do I put for the xsl:value-of select="" inside the xsl:for-each ? Is what I am trying to do impossible?

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  • Python: Is there a way to reflectivly list all attributes of a class

    - by hhafez
    Given a class such as def MyClass text = "hello" number = 123 Is there a way in python to inspect MyClass an determine that it has the two attributes text and number. I can not use something like inspect.getSource(object) because the class I am to get it's attributes for are generate using SWIG (so they are hidden in .so :) ). So I am really looking for something equivalant to Java's [Class.getDeclardFields][1] Any help would be appreciated, otherwise I'll have to solve this problem with SWIG + JAVA instead of SWIG + Python.

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