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  • 'Forward-Compatible' Program Design

    - by Jeffrey Kern
    The majority of my questions I've asked here so far on StackOverflow have been how to implement individual concepts and techniques towards developing a software-based NES clone via the XNA environment. The small samples that I've thrown together on my PC work relatively great and everything. Except I hit a brick wall. How do I merge all of these samples together. Having proof-of-concept is amazing, except when you need it to go beyond just that. I now have samples strewn about that I'm trying to merge, some of them incomplete. And now I'm stuck with the chicken-and-the-egg situation of where I would like to incorporate these samples together, to make sure they work, but I cannot without test data. And I don't have tools to create test data, because they'd need to be based off of the individual pieces that need to be put together. In my mind, I'm having nightmares with circular reference. For my sample data, I am hoping to save it in XML and write a specification - and then make sample data by hand - but I'm too paranoid of manually creating an XML file full of incorrect data and blaming it on my code, or vice-versa. It doesn't help that the end-result of my work is graphic-oriented, which makes it interseting how a graphic on the screen can be visualized in XML Nodes. I guess, my question is this: What design patterns and disciplines exist in the coding world that address this type of concern? I've always relied on brute-force coding and restarting a project with a whole new code base in attempts to further along my goals, but I doubt that would be the best way to do so. Within my college career, the majority of my programming was to work on simple projects that came out of a book, or with a given correct data set and a verifyable result. I don't have that, as my own design documents that I am going by could be terribly wrong.

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  • What are the worst examples of moral failure in the history of software engineering?

    - by Amanda S
    Many computer science curricula include a class or at least a lecture on disasters caused by software bugs, such as the Therac-25 incidents or Ariane 5 Flight 501. Indeed, Wikipedia has a list of software bugs with serious consequences, and a question on StackOverflow addresses some of them too. We study the failures of the past so that we don't repeat them, and I believe that rather than ignoring them or excusing them, it's important to look at these failures squarely and remind ourselves exactly how the mistakes made by people in our profession cost real money and real lives. By studying failures caused by uncaught bugs and bad process, we learn certain lessons about rigorous testing and accountability, and we make sure that our innocent mistakes are caught before they cause major problems. There are kinds of less innocent failure in software engineering, however, and I think it's just as important to study the serious consequences caused by programmers motivated by malice, greed, or just plain amorality. Thus we can learn about the ethical questions that arise in our profession, and how to respond when we are faced with them ourselves. Unfortunately, it's much harder to find lists of these failures--the only one I can come up with is that apocryphal "DOS ain't done 'til Lotus won't run" story. What are the worst examples of moral failure in the history of software engineering?

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  • ASP .NET confusion - server controls

    - by Brandi
    I have read through the information in this question: http://stackoverflow.com/questions/22084/asp-net-aspxxx-controls-versus-standard-html but am still rather confused. The situation was I was asked to do a web project where I made a wizard. When I was done with the project everyone asked why I had used an <asp:Wizard...>. I thought this was what was being asked for, but apparently not, so after this I was led to believe that server controls were just prototyping tools. However, the next project I did my DB queries through C# code-behind and loaded the results via html. I was then asked why I had not used a gridview and a dataset. Does anyone have a list of pros and cons why they would choose to use specific html controls over specific server controls and why? I guess I'm looking for a list... what server controls are okay to use and why? EDIT: I guess this question is open ended, so I'll clarify a few more specific questions... Is it okay to use very simple controls such as asp:Label or do these just end up wasting space? It seems like it would be difficult to access html in the code behind otherwise. Are there a few controls that should just never be used? Does anyone have a good resource that will show me pros and cons of each control?

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  • FQL query using stream table doesn't accept app access token

    - by tougher
    I've searched stackoverflow all day long to find an answer without luck, so here we go. I'm trying to fetch data from the stream table like this: FQL: SELECT post_id, message, created_time FROM stream WHERE source_id = 131559313586863 URL: http:// graph.facebook.com/fql?q=SELECT+post_id%2C+message%2C+created_time+FROM+stream+WHERE+source_id+%3D+131559313586863&access_token=10669xxxxx74470|PF-7GSdBx0Nxxxxxkdi1KwSQG-w But I get a 400 Bad Request as response with the error message: "An access token is required to request this resource.". I'm fetching an application access token with this url: https:// graph.facebook.com/oauth/access_token?client_id=FACEBOOK_APP_ID&client_secret=FACEBOOK_APP_SECRET&grant_type=client_credentials Facebook state in this blog post that "You will need to pass a valid app or user access token to access this functionality.". Functionality refers to /feed and /posts (the stream table). Futhermore this wiki tells the same story about using the stream table, "From June 3 2011 a token is required to query this table. You can use any application or user token to make the query.". Does anyone see my hopefully obvious flaw? Please note: The profile in the FQL query is public. I need this to run userless though a cronjob. No user interaction is possible. The request works if I replace the app access token with my own user token from https:// developers.facebook.com/tools/explorer Sorry for breaking the URL's. I need more reputation to post more than 2 links :-/

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  • What version of .NET containing RuntimeMethodHandle.EmptyHandle?

    - by user299990
    No one answers my question in http://stackoverflow.com/questions/1295344/difference-between-activator-createinstance-and-typeoft-invokemember-with-b/2500960#2500960. I guess that the issue is closed and I am asking here again. Ben M have a nice function which I need for a project. The function is - public static T CreateInstance() { bool bNeedSecurityCheck = true; bool canBeCached = false; RuntimeMethodHandle emptyHandle = RuntimeMethodHandle.EmptyHandle; return (T) RuntimeTypeHandle.CreateInstance(typeof(T) as RuntimeType, true, true, ref canBeCached, ref emptyHandle, ref bNeedSecurityCheck); } I am using .NET 3.5 and Visual studio 2008. It gives the error "EmptyHandle type name does not exist in the type System.RuntimeMethodHandle". Then I used "RuntimeMethodHandle emptyHandle = new RuntimeMethodHandle();". Another error presents. RuntimeTypeHandle does not have a CreateInstance method either. Activator has. But it does not take any ref parameter. Thanks for clarification in advance!

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  • FluentNHibernate, getting 1 column from another table

    - by puffpio
    We're using FluentNHibernate and we have run into a problem where our object model requires data from two tables like so: public class MyModel { public virtual int Id { get; set; } public virtual string Name { get; set; } public virtual int FooId { get; set; } public virtual string FooName { get; set; } } Where there is a MyModel table that has Id, Name, and FooId as a foreign key into the Foo table. The Foo tables contains Id and FooName. This problem is very similar to another post here: http://stackoverflow.com/questions/1896645/nhibernate-join-tables-and-get-single-column-from-other-table but I am trying to figure out how to do it with FluentNHibernate. I can make the Id, Name, and FooId very easily..but mapping FooName I am having trouble with. This is my class map: public class MyModelClassMap : ClassMap<MyModel> { public MyModelClassMap() { this.Id(a => a.Id).Column("AccountId").GeneratedBy.Identity(); this.Map(a => a.Name); this.Map(a => a.FooId); // my attempt to map FooName but it doesn't work this.Join("Foo", join => join.KeyColumn("FooId").Map(a => a.FooName)); } } with that mapping I get this error: The element 'class' in namespace 'urn:nhibernate-mapping-2.2' has invalid child element 'join' in namespace 'urn:nhibernate-mapping-2.2'. List of possible elements expected: 'joined-subclass, loader, sql-insert, sql-update, sql-delete, filter, resultset, query, sql-query' in namespace 'urn:nhibernate-mapping-2.2'. any ideas?

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  • Legal issues in Europe: check patents ?

    - by Bugz R us
    We live in Europe and are releasing commercial software in multiple countries. Besides of the licensing issues (GPL/LGPL/...) we have a question about patents. I know that if you're in the US, before you release software, you have to check if there aren't any patents you're infringing upon. I also know most of these patents or usually irrational and form a heavy burden on developers/software engineers. Now, as far as I know, EU rules are lots more ratinal, but there has been lobbying to also apply the same rules in EU. http://www.nosoftwarepatents.com http://www.stopsoftwarepatents.eu So what's the deal actually ? For example, there's mention of a patent on a shopping cart : http://v3.espacenet.com/publicationDetails/biblio?CC=EP&NR=807891&KC=&FT=E Is that true ? Is a "shopping cart" patented ??? .................. http://stackoverflow.com/questions/1396191/what-should-every-developer-know-about-legal-matters : 4.Software patent lawsuits are crap shoots. You should not, of course, knowingly violate a software patent. However, there is a small but real chance some company will sue you for violating their patent. This may happen even if you develop your software independently, you never heard of the patent, and the patent covers a technique that is intuitively obvious and almost completely unrelated to your software. There is not a lot you can do to avoid this, given the current USPTO policies, other than buy insurance. The good news is that patent trolls generally sue large companies with lots of money.

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  • C# connect to domain SQL Server 2005 from non-domain machine

    - by user304582
    Hi, I asked a question a few days ago (http://stackoverflow.com/questions/2795723/access-to-sql-server-2005-from-a-non-domain-machine-using-windows-authentication) which got some interesting, but not usable suggestions. I'd like to ask the question again, but make clear what my constraints are: I have a Windows domain within which a machine is running SQL Server 2005 and which is configured to support only Windows authentication. I would like to run a C# client application on a machine on the same network, but which is NOT on the domain, and access a database on the SQL Server 2005 instance. I CANNOT create or modify OS or SQL Server users on either machine, and I CANNOT make any changes to permissions or impersonation, and I CANNOT make use of runas. I know that I can write Perl and Java applications that can connect to the SQL Server database using only these four parameters: server name, database name, username (in the form domain\user), and password. In C# I have tried various things around: string connectionString = "Data Source=server;Initial Catalog=database;User Id=domain\user;Password=password"; SqlConnection connection = new SqlConnection(connectionString); connection.Open(); and tried setting integrated security to true and false, but nothing seems to work. Is what I am trying to do simply impossible in C#? Thanks for any help, Martin

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  • JUnit confusion: use 'extend Testcase' or '@Test' ?

    - by Rabarberski
    I've found the proper use (or at least the documentation) of JUnit very confusing. This question serves both as a future reference and as a real question. If I've understood correctly, there are two main approaches to create and run a JUnit test: Approach A: create a class that extends TestCase, and start test methods with the word test. When running the class as a JUnit Test (in Eclipse), all methods starting with the word test are automatically run. import junit.framework.TestCase; public class DummyTestA extends TestCase { public void testSum() { int a = 5; int b = 10; int result = a + b; assertEquals(15, result); } } Approach B: create a 'normal' class and prepend a @Test annotation to the method. Note that you do NOT have to start the method with the word test. import org.junit.*; import static org.junit.Assert.*; public class DummyTestB { @Test public void Sum() { int a = 5; int b = 10; int result = a + b; assertEquals(15, result); } } Mixing the two seems not to be a good idea, see e.g. this stackoverflow question: Now, my questions(s): What is the preferred approach, or when would you use one instead of the other? Approach B allows for testing for exceptions by extending the @Test annotation like in @Test(expected = ArithmeticException.class). But how do you test for exceptions when using approach A? When using approach A, you can group a number of test classes in a test suite. TestSuite suite = new TestSuite("All tests");<br/> suite.addTestSuite(DummyTestA.class); suite.addTestSuite(DummyTestAbis.class);` But this can't be used with approach B (since each testclass should subclass TestCase). What is the proper way to group tests for approach B?

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  • POST a form in an iframe.

    - by Stavros Korokithakis
    I would like to POST a form in an iframe, generated like so: My JS loads an iframe inside the page, adds a form to the iframe and submits the form. What I would like to happen is the iframe to load the result of that request. So, I would effectively like to post a form and render the result inside the iframe, without touching the parent (apart from putting the iframe up for display in the first place). I am using the code from this answer: http://stackoverflow.com/questions/133925/javascript-post-request-like-a-form-submit/134003#134003 but I can't get it to not reload the parent. I post the form, and instead of the iframe refreshing, the entire parent refreshes. I don't know why that is, since the url it's posting to is different and would at least redirect there. Can anyone help me with this problem? I just want a post inside an iframe and only within the iframe, basically. EDIT: After some more research, apparently the form is not being created properly. I'm using document.createElement("form") and then document.getElementById("my_iframe_id").appendChild(form) to append it, but it does not seem to be working correctly.

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  • How to customize the process employed by WCF when serializing contract method arguments?

    - by mark
    Dear ladies and sirs. I would like to formulate a contrived scenario, which nevertheless has firm actual basis. Imagine a collection type COuter, which is a wrapper around an instance of another collection type CInner. Both implement IList (never mind the T). Furthermore, a COuter instance is buried inside some object graph, the root of which (let us refer to it as R) is returned from a WCF service method. My question is how can I customize the WCF serialization process, so that when R is returned, the request to serialize the COuter instance will be routed through my code, which will extract CInner and pass it to the serializer instead. Thus the receiving end still gets R, only no COuter instance is found in the object graph. I hoped that http://stackoverflow.com/questions/2220516/how-does-wcf-serialize-the-method-call will contain the answer, unfortunately the article mentioned there (http://msdn.microsoft.com/en-us/magazine/cc163569.aspx) only barely mentions that advanced serialization scenarios are possible using IDataContractSurrogate interface, but no details are given. I am, on the other hand, would really like to see a working example. Thank you very much in advance.

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  • Android, how to use DexClassLoader to dynamically replace an Activity or Service

    - by RickNotFred
    I am trying to do something similar to this stackoverflow posting. What I want to do is to read the definition of an activity or service from the SD card. To avoid manifest permission issues, I create a shell version of this activity in the .apk, but try to replace it with an activity of the same name residing on the SD card at run time. Unfortunately, I am able to load the activity class definition from the SD card using DexClassLoader, but the original class definition is the one that is executed. Is there a way to specify that the new class definition replaces the old one, or any suggestions on avoiding the manifest permission issues without actually providing the needed activity in the package? The code sample: ClassLoader cl = new DexClassLoader("/sdcard/mypath/My.apk", getFilesDir().getAbsolutePath(), null, MainActivity.class.getClassLoader()); try { Class<?> c = cl.loadClass("com.android.my.path.to.a.loaded.activity"); Intent i = new Intent(getBaseContext(), c); startActivity(i); } catch (Exception e) { Intead of launching the com.android.my.path.to.a.loaded.activity specified in /sdcard/mypath/My.apk, it launches the activity statically loaded into the project.

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  • How to use a class's type as the type argument for an inherited collection property in C#

    - by Edelweiss Peimann
    I am trying to create a representation of various types of card that inherit from a generic card class and which all contain references to their owning decks. I tried re-declaring them, as suggested here, but it still won't convert to the specific card type. The code I currently have is as such: public class Deck<T> : List<T> where T : Card { void Shuffle() { throw new NotImplementedException("Shuffle not yet implemented."); } } public class Card { public Deck<Card> OwningDeck { get; set; } } public class FooCard : Card { public Deck<FooCard> OwningDeck { get { return (Deck<FooCard>)base.OwningDeck; } set { OwningDeck = value; } } } The compile-time error I am getting: Error 2 Cannot convert type 'Game.Cards.Deck' to 'Game.Cards.Deck' And a warning suggesting I use a new operator to specify that the hiding is intentional. Would doing so be a violation of convention? Is there a better way? My question to stackoverflow is this: Can what I am trying to do be done elegantly in the .NET type system? If so, can some examples be provided?

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  • Floating Point Arithmetic - Modulo Operator on Double Type

    - by CrimsonX
    So I'm trying to figure out why the modulo operator is returning such a large unusual value. If I have the code: double result = 1.0d % 0.1d; it will give a result of 0.09999999999999995. I would expect a value of 0 Note this problem doesn't exist using the dividing operator - double result = 1.0d / 0.1d; will give a result of 10.0, meaning that the remainder should be 0. Let me be clear: I'm not surprised that an error exists, I'm surprised that the error is so darn large compared to the numbers at play. 0.0999 ~= 0.1 and 0.1 is on the same order of magnitude as 0.1d and only one order of magnitude away from 1.0d. Its not like you can compare it to a double.epsilon, or say "its equal if its < 0.00001 difference". I've read up on this topic on StackOverflow, in the following posts one two three, amongst others. Can anyone suggest explain why this error is so large? Any any suggestions to avoid running into the problems in the future (I know I could use decimal instead but I'm concerned about the performance of that).

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  • Retrieve OpenId FullName from Google

    - by user294711
    I'm using DotNetOpenAuth lib to work with Google(only) OpenId. And I'm retrieving Email without any problem. But I can't get FullName, it is always null. request.AddExtension(new ClaimsRequest { Email = DemandLevel.Require, FullName = DemandLevel.Require }); ClaimsResponse claimsResponse = relyingPartyResponse.GetExtension<ClaimsResponse>(); if (claimsResponse != null) { var email = claimsResponse.Email; var fullName = claimsResponse.FullName; } I googled this problem and found that: Glad you got it working. Google will not give a full name or nickname for their users. They ONLY give email address, and (I think, but perhaps only on a white list) the timezone. It's not a matter of figuring out how to rig your RP so that it works. Google just won't do it yet. – Andrew Arnott Sep 8 at 14:22 stackoverflow.com/questions/1387438/retrieve-openid-user-information-claims-across-providers But it was in Sep 2009, maybe something was changed from that moment... I've found that in http://code.google.com/apis/accounts/docs/OpenID.html: openid.ax.required -- (required) Specifies the attribute being requested. Valid values include: "country", "email", "firstname", "language", "lastname". To request multiple attributes, set this parameter to a comma-delimited list of attributes. So, my question is how can I get FullName (FirstName, LastName) from Google OpenId?

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  • Java webapp: how to implement a web bug (1x1 pixel)?

    - by NoozNooz42
    In the accepted answer in the following question, a SO regular with 13K+ rep suggests to use a "web bug" (non-cacheable 1x1 img) to be able to track requests in the logs: http://stackoverflow.com/questions/1784893 How can I do this in Java? Basically, I've got two issues: how to make sure the 1x1 image is not cacheable (how to set the header)? how to make sure the query for these 1x1 image will appear in the logs? I'm looking for exact piece of code because I know how to write a .jsp/servlet and I know how to serve an 1x1 image :) My question is really about the exact .jsp/servlet that I should write and how/what needs to be done so that Tomcat logs the request. For example I plan to use the following mapping: <servlet-mapping> <servlet-name>WebBugServlet</servlet-name> <url-pattern>/webbug*</url-pattern> </servlet-mapping> and then use an img tag referencing a "webbug.png" (or .gif), so how do I write the .jsp/servlet? What/where should I look for in the logs?

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  • Java Random Slowdowns on Mac OS cont'd

    - by javajustice
    I asked this question a few weeks ago, but I'm still having the problem and I have some new hints. The original question is here: http://stackoverflow.com/questions/1651887/java-random-slowdowns-on-mac-os Basically, I have a java application that splits a job into independent pieces and runs them in separate threads. The threads have no synchronization or shared memory items. The only resources they do share are data files on the hard disk, with each thread having an open file channel. Most of the time it runs very fast, but occasionally it will run very slow for no apparent reason. If I attach a CPU profiler to it, then it will start running quickly again. If I take a CPU snapshot, it says its spending most of its time in "self time" in a function that doesn't do anything except check a few (unshared unsynchronized) booleans. I don't know how this could be accurate because 1, it makes no sense, and 2, attaching the profiler seems to knock the threads out of whatever mode they're in and fix the problem. Also, regardless of whether it runs fast or slow, it always finishes and gives the same output, and it never dips in total cpu usage (in this case ~1500%), implying that the threads aren't getting blocked. I have tried different garbage collectors, different sizings the parts of the memory space, writing data output to non-raid drives, and putting all data output in threads separate the main worker threads. Does anyone have any idea what kind of problem this could be? Could it be the operating system (OS X 10.6.2) ? I have not been able to duplicate it on a windows machine, but I don't have one with a similar hardware configuration.

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  • Customizing the TFS 2008 build sequence to avoid compilation and deploy SSRS

    - by Andrew
    I'm trying to create a CI process for SQL Server Reporting Services. I am fairly new to TFS but quite experienced with MSBuild. In the past I've used a combination of MSBuild with Team City so the whole build process is more or less custom. Here lies the start of my problems, as the solution I am deploying only contains Report Server projects (rds), no compilation is required. I thought that I would override the the first default task that TFS runs (EndToEndIteration) to override the default TFS build sequence and inject my own. The first snag that I have come across is that the build always fails, how can I set the status of the build to success? Currently the EndToEndIteration task is very light and only has a message. Is this the best method to create a custom build process in TFS where compilation is not required? Or should I use the default sequence and override one of the hook tasks mentioned in http://msdn.microsoft.com/en-us/library/aa337604%28VS.80%29.aspx (ie: AfterCompile) The core steps that I'd like to achieve are: Bundle the RDL and datasource files Connect to the host server to register/deploy the reports Re-apply any subscriptions that previously existed Run tests to verify the deployment succeeded and is returning results as expected I have found another article on Report services deployment: http://stackoverflow.com/questions/88710/reporting-services-deployment But it doesn't mention the best practice for customizing the standard build process. Any help would be appreciated.

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  • ASP.NET AsyncPostBackTrigger disables button's OnClick function???

    - by hahuang65
    I saw another post like this: http://stackoverflow.com/questions/1795621/asyncpostbacktrigger-disables-buttons But I don't really know what to make of it. The accepted answer was poorly typed. Basically, I have a button with an OnClick function. I also have a UpdatePanel, with is AsyncPostBackTrigger set to that same button. It seems that if I do this, my Button no longer does ANYTHING. I guess it's because I have a Page_Load() event... Can anyone explain why this is? And how should I set up my webpage if I can't use the Page_Load() function? Oh and if I put my Button in a UpdatePanel, it also won't do anything, probably because of the same reason. This is a section of my code: <asp:FileUpload id="FileUploadControl" runat="server" /> <asp:Button runat="server" id="UploadButton" text="Upload" OnClick="uploadClicked" /> <br /><br /> <asp:Label runat="server" id="StatusLabel" text="Upload status: " /> <br /> <asp:UpdatePanel ID="UpdatePanel2" runat="server" updatemode="Conditional" > <ContentTemplate> <asp:DropDownList ID="songList" runat="server" /> </ContentTemplate> <Triggers> <asp:AsyncPostBackTrigger ControlID="RefreshButton" /> </Triggers> </asp:UpdatePanel> Thanks in advance.

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  • Why can't pass Marshaled interface as integer(or pointer)

    - by cemick
    I passed ref of interface from Visio Add-ins to MyCOMServer (http://stackoverflow.com/questions/2455183/interface-marshalling-in-delphi).I have to pass interface as pointer in internals method of MyCOMServer. I try to pass interface to internal method as pointer of interface, but after back cast when i try call method of interface I get exception. Simple example(Fisrt block execute without error, but At Second block I get Exception after addressed to property of IVApplication interface): procedure TMyCOMServer.test(const Interface_:IDispatch); stdcall; var IMy:_IMyInterface; V: Variant; Str: String; I: integer; Vis: IVApplication; begin ...... Self.QuaryInterface(_IMyInterface,IMy); str := IA.ApplicationName; V := Integer(IMy); i := V; Pointer(IMy) := Pointer(i); str := IMy.SomeProperty; // normal completion str := (Interface_ as IVApplication).Path; V := Interface_; I := V; Pointer(Vis) := Pointer(i); str := Vis.Path; // 'access violation at 0x76358e29: read of address 0xfeeefeee' end; Why I can't do like this?

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  • How to deploy a number of disparate project types?

    - by niteice
    This question is similar to http://stackoverflow.com/questions/1900269/whats-the-best-way-to-deploy-an-executable-process-on-a-web-server. The situation is this: I'm developing a product that needs to be deployed to a web server. It consists of 4 website projects, a background service, a couple of command-line tools, and two assemblies shared by all of these components. Now, I also happen to administer the server that this product will be deployed on. So I'm familiar with everything that may need to be done to perform an update: Copy website files Replace the service binary Install updated components in the GAC Configure IIS Update database schema After some research it seems that, to reduce deployment time and to be able to let the other sysadmins handle deployment, I want to deploy all of these as an MSI, except that I don't know a thing about installers. I know VS can generate web deployment projects, but where do I go from there? Being able to simply click Next a few times on an installer is my goal for deploying updates. It would also be nice to modularize it, so for example, I could distribute the four websites among multiple servers and have everything appear as individual components in the installer, and as one entity in Add/Remove Programs. Is all of this too much to ask in a single package?

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  • finding ALL cycles in a huge sparse matrix

    - by Andy
    Hi there, First of all I'm quite a Java beginner, so I'm not sure if this is even possible! Basically I have a huge (3+million) data source of relational data (i.e. A is friends with B+C+D, B is friends with D+G+Z (but not A - i.e. unmutual) etc.) and I want to find every cycle within this (not necessarily connected) directed graph. I've found this thread (http://stackoverflow.com/questions/546655/finding-all-cycles-in-graph/549402#549402) which has pointed me to Donald Johnson's (elementary) cycle-finding algorithm which, superficially at least, looks like it'll do what I'm after (I'm going to try when I'm back at work on Tuesday - thought it wouldn't hurt to ask in the meanwhile!). I had a quick scan through the code of the Java implementation of Johnson's algorithm (in that thread) and it looks like a matrix of relations is the first step, so I guess my questions are: a) Is Java capable of handling a 3+million*3+million matrix? (was planning on representing A-friends-with-B by a binary sparse matrix) b) Do I need to find every connected subgraph as my first problem, or will cycle-finding algorithms handle disjoint data? c) Is this actually an appropriate solution for the problem? My understanding of "elementary" cycles is that in the graph below, rather than picking out A-B-C-D-E-F it'll pick out A-B-F, B-C-D etc. but that's not the end of the world given the task. E / \ D---F / \ / \ C---B---A d) If necessary, I can simplify the problem by enforcing mutuality in relations - i.e. A-friends-with-B <== B-friends-with-A, and if really necessary I can maybe cut down the data size, but realistically it is always going to be around the 1mil mark. z) Is this a P or NP task?! Am I biting off more than I can chew? Thanks all, any help appreciated! Andy

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  • retrieving multiple versions through API through hbase

    - by sammy
    hello , this is a continuation of my previous question where id used hbase shell.. http://stackoverflow.com/questions/3024417/facing-problems-while-updating-rows-in-hbase i tried the same with API.. im not able to figure out how to retrieve all versions , iterate and print their values for a specific row... i've spending hours reading... please help me out... Scan s = new Scan(Bytes.toBytes("row1")); s.addColumn(Bytes.toBytes("column"),Bytes.toBytes("address")); SETTING RANGE FOR THE VERSIONS s.setTimeRange(0L,6L); ResultScanner scanner = table.getScanner(s); for (Result r : scanner) { for(KeyValue kv : r.sorted()) { System.out.println("To"+kv.getTimestamp()); System.out.println("from "+Bytes.toString(kv.getKey())); System.out.println("To "+Bytes.toString(kv.getValue())); } scanner.close(); } here im intending to print all versions of the column..... but it gives the most recent one... im stuck here...

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  • Global Temporary Table "On commit delete rows" functionality discrepancy.

    - by TomatoSandwich
    I have a global temporary table. I called my GTT, for that was it's initials. My GTT never hurt anyone, and did everything I bade of it. I asked my GTT to delete rows on commit. This is a valid function in the creation script of my GTT in oracle. I wanted to be able to have different users see GTT with their own data, and not the data of other people's sessions. 'Delete rows on commit' worked perfectly in our test environment. GTT and I were happy. But then, I deployed GTT as part of an update to functionality to a client's database. The database doesn't like to play well with GTT. GTT called me up all upset and worried, because it wasn't holding any data any more, and didn't know why. GTT told me that if someone did: insert into my_GTT (description) values ('Happy happy joy joy') he would sing-song back: 1 row inserted. However, if the same person tried select * from my_GTT; GTT didn't know what to do, and he replied 0 rows returned. GTT was upset that he didn't know what his playmate had inserted. Please, Stackoverflow, why would GTT forget what was placed into him? He can remember perfectly well at home, but out in the cold harsh world, he just gets so scared. :(

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  • dealing cards in Clojure

    - by Ralph
    I am trying to write a Spider Solitaire player as an exercise in learning Clojure. I am trying to figure out how to deal the cards. I have created (with the help of stackoverflow), a shuffled sequence of 104 cards from two standard decks. Each card is represented as a (defstruct card :rank :suit :face-up) The tableau for Spider will be represented as follows: (defstruct tableau :stacks :complete) where :stacks is a vector of card vectors, 4 of which contain 5 cards face down and 1 card face up, and 6 of which contain 4 cards face down and 1 card face up, for a total of 54 cards, and :complete is an (initially) empty vector of completed sets of ace-king (represented as, for example, king-hearts, for printing purposes). The remainder of the undealt deck should be saved in a ref (def deck (ref seq)) During the game, a tableau may contain, for example: (struct-map tableau :stacks [[AH 2C KS ...] [6D QH JS ...] ... ] :complete [KC KS]) where "AH" is a card containing {:rank :ace :suit :hearts :face-up false}, etc. How can I write a function to deal the stacks and then save the remainder in the ref?

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