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  • Not loading associations without proxies in NHibernate

    - by Alice
    I don't like the idea of proxy and lazy loading. I don't need that. I want pure POCO. And I want to control loading associations explicitly when I need. Here is entity public class Post { public long Id { get; set; } public long OwnerId { get; set; } public string Content { get; set; } public User Owner { get; set; } } and mapping <class name="Post"> <id name="Id" /> <property name="OwnerId" /> <property name="Content" /> <many-to-one name="Owner" column="OwnerId" /> </class> However if I specify lazy="false" in the mapping, Owner is always eagerly fetched. I can't remove many-to-one mapping because that also disables explicit loading or a query like from x in session.Query<Comment>() where x.Owner.Title == "hello" select x; I specified lazy="true" and set use_proxy_validator property to false. But that also eager loads Owner. Is there any way to load only Post entity?

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  • Castle Windsor: Reuse resolved component in OnCreate, UsingFactoryMethod or DynamicParameters

    - by shovavnik
    I'm trying to execute an action on a resolved component before it is returned as a dependency to the application. For example, with this graph: public class Foo : IFoo { } public class Bar { IFoo _foo; IBaz _baz; public Bar(IFoo foo, IBaz baz) { _foo = foo; _baz = baz; } } When I create an instance of IFoo, I want the container to instantiate Bar and pass the already-resolved IFoo to it, along with any other dependencies it requires. So when I call: var foo = container.Resolve<IFoo>(); The container should automatically call: container.Resolve<Bar>(); // should pass foo and instantiate IBaz I've tried using OnCreate, DynamicParameters and UsingFactoryMethod, but the problem they all share is that they don't hold an explicit reference to the component: DynamicParameters is called before IFoo is instantiated. OnCreate is called after, but the delegate doesn't pass the instance. UsingFactoryMethod doesn't help because I need to register these components with TService and TComponent. Ideally, I'd like a registration to look something like this: container.Register<IFoo, Foo>((kernel, foo) => kernel.Resolve<Bar>(new { foo })); Note that IFoo and Bar are registered with the transient life style, which means that the already-resolved instance has to be passed to Bar - it can't be "re-resolved". Is this possible? Am I missing something?

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  • Omit return type in C++0x

    - by Clinton
    I've recently found myself using the following macro with gcc 4.5 in C++0x mode: #define RETURN(x) -> decltype(x) { return x; } And writing functions like this: template <class T> auto f(T&& x) RETURN (( g(h(std::forward<T>(x))) )) I've been doing this to avoid the inconvenience having to effectively write the function body twice, and having keep changes in the body and the return type in sync (which in my opinion is a disaster waiting to happen). The problem is that this technique only works on one line functions. So when I have something like this (convoluted example): template <class T> auto f(T&& x) -> ... { auto y1 = f(x); auto y2 = h(y1, g1(x)); auto y3 = h(y1, g2(x)); if (y1) { ++y3; } return h2(y2, y3); } Then I have to put something horrible in the return type. Furthermore, whenever I update the function, I'll need to change the return type, and if I don't change it correctly, I'll get a compile error if I'm lucky, or a runtime bug in the worse case. Having to copy and paste changes to two locations and keep them in sync I feel is not good practice. And I can't think of a situation where I'd want an implicit cast on return instead of an explicit cast. Surely there is a way to ask the compiler to deduce this information. What is the point of the compiler keeping it a secret? I thought C++0x was designed so such duplication would not be required.

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  • sqlalchemy dynamic mapping

    - by adancu
    Hi, I have the following problem: I have the class: class Word(object): def __init__(self): self.id = None self.columns = {} def __str__(self): return "(%s, %s)" % (str(self.id), str(self.columns)) self.columns is a dict which will hold (columnName:columnValue) values. The name of the columns are known at runtime and they are loaded in a wordColumns list, for example wordColumns = ['english', 'korean', 'romanian'] wordTable = Table('word', metadata, Column('id', Integer, primary_key = True) ) for columnName in wordColumns: wordTable.append_column(Column(columnName, String(255), nullable = False)) I even created a explicit mapper properties to "force" the table columns to be mapped on word.columns[columnName], instead of word.columnName, I don't get any error on mapping, but it seems that doesn't work. mapperProperties = {} for column in wordColumns: mapperProperties['columns[\'%']' % column] = wordTable.columns[column] mapper(Word, wordTable, mapperProperties) When I load a word object, SQLAlchemy creates an object which has the word.columns['english'], word.columns['korean'] etc. properties instead of loading them into word.columns dict. So for each column, it creates a new property. Moreover word.columns dictionary doesn't even exists. The same way, when I try to persist a word, SQLAlchemy expects to find the column values in properties named like word.columns['english'] (string type) instead of the dictionary word.columns. I have to say that my experience with Python and SQLAlchemy is quite limited, maybe it isn't possible to do what I'm trying to do. Any help appreciated, Thanks in advance.

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  • Reading a C/C++ data structure in C# from a byte array

    - by Chris Miller
    What would be the best way to fill a C# struct from a byte[] array where the data was from a C/C++ struct? The C struct would look something like this (my C is very rusty): typedef OldStuff { CHAR Name[8]; UInt32 User; CHAR Location[8]; UInt32 TimeStamp; UInt32 Sequence; CHAR Tracking[16]; CHAR Filler[12];} And would fill something like this: [StructLayout(LayoutKind.Explicit, Size = 56, Pack = 1)]public struct NewStuff{ [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)] [FieldOffset(0)] public string Name; [MarshalAs(UnmanagedType.U4)] [FieldOffset(8)] public uint User; [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)] [FieldOffset(12)] public string Location; [MarshalAs(UnmanagedType.U4)] [FieldOffset(20)] public uint TimeStamp; [MarshalAs(UnmanagedType.U4)] [FieldOffset(24)] public uint Sequence; [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)] [FieldOffset(28)] public string Tracking;} What is best way to copy OldStuff to NewStuff, if OldStuff was passed as byte[] array? I'm currently doing something like the following, but it feels kind of clunky. GCHandle handle;NewStuff MyStuff;int BufferSize = Marshal.SizeOf(typeof(NewStuff));byte[] buff = new byte[BufferSize];Array.Copy(SomeByteArray, 0, buff, 0, BufferSize);handle = GCHandle.Alloc(buff, GCHandleType.Pinned);MyStuff = (NewStuff)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(NewStuff));handle.Free(); Is there better way to accomplish this?

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  • Design by contracts and constructors

    - by devoured elysium
    I am implementing my own ArrayList for school purposes, but to spice up things a bit I'm trying to use C# 4.0 Code Contracts. All was fine until I needed to add Contracts to the constructors. Should I add Contract.Ensures() in the empty parameter constructor? public ArrayList(int capacity) { Contract.Requires(capacity > 0); Contract.Ensures(Size == capacity); _array = new T[capacity]; } public ArrayList() : this(32) { Contract.Ensures(Size == 32); } I'd say yes, each method should have a well defined contract. On the other hand, why put it if it's just delegating work to the "main" constructor? Logicwise, I wouldn't need to. The only point I see where it'd be useful to explicitly define the contract in both constructors is if in the future we have Intelisense support for contracts. Would that happen, it'd be useful to be explicit about which contracts each method has, as that'd appear in Intelisense. Also, are there any books around that go a bit deeper on the principles and usage of Design by Contracts? One thing is having knowledge of the syntax of how to use Contracts in a language (C#, in this case), other is knowing how and when to use it. I read several tutorials and Jon Skeet's C# in Depth article about it, but I'd like to go a bit deeper if possible. Thanks

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  • Is it a bug???????????????/

    - by Knowing me knowing you
    I'm using VS2010 Ultimate. Having code: //file IntSet.h #include "stdafx.h" #pragma once /*Class representing set of integers*/ template<class T> class IntSet { private: T** myData_; std::size_t mySize_; std::size_t myIndex_; public: #pragma region ctor/dtor explicit IntSet(); virtual ~IntSet(); #pragma endregion #pragma region publicInterface IntSet makeUnion(const IntSet&)const; IntSet makeIntersection(const IntSet&)const; IntSet makeSymmetricDifference(const IntSet&)const; void insert(const T&); #pragma endregion }; //file IntSet_impl.h #include "StdAfx.h" #include "IntSet.h" #pragma region ctor/dtor template<class T> IntSet<T>::IntSet():myData_(nullptr), mySize_(0), myIndex_(0) { } template<class T> IntSet<T>::~IntSet() { } #pragma endregion #pragma region publicInterface template<class T> void IntSet<T>::insert(const T& obj) {/*IF I SET A BREAKPOINT HERE AND AFTER THAT I CHANGE SOMETHING IN THE BODY I'M GETTING MSG SAYING THAT THE BREAKPOINT WILL NOT CURRENTLY BE HIT, AFTER I REBUILD THE BREAKPOINT IS VALID AGAIN*/ /*Check if we are initialized*/ if (mySize_ == 0) { mySize_ = 1; myData_ = new T*[mySize_]; } /*Check if we have place to insert obj in.*/ if (myIndex_ < mySize_) { myData_[myIndex_++] = new T(obj); return; } /*We didn't have enough place...*/ T** tmp = new T*[mySize_];//for copying old to temporary basket std::copy(&myData_[0],&myData_[mySize_],&tmp[0]); delete myData_; auto oldSize = mySize_; mySize_ *= 2; myData_ = new T*[mySize_]; std::copy(&tmp[0],&tmp[oldSize],&myData_[0]); myData_[myIndex_] = new T(obj); ++myIndex_; } #pragma endregion Thanks.

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  • Setting Nullable Integer to String Containing Nothing yields 0

    - by Brian MacKay
    I've been pulling my hair out over some unexpected behavior from nullable integers. If I set an Integer to Nothing, it becomes Nothing as expected. If I set an Integer? to a String that is Nothing, it becomes 0! Of course I get this whether I explicitly cast the String to Integer? or not. I realize I could work around this pretty easily but I want to know what I'm missing. Dim NullString As String = Nothing Dim NullableInt As Integer? = CType(NullString, Integer?) 'Expected NullableInt to be Nothing, but it's 0! NullableInt = Nothing 'This works -- NullableInt now contains Nothing. How is this EDIT: Previously I had my code up here so without the explicit conversion to 'Integer?' and everyone seemed to be fixated on that. I want to be clear that this is not an issue that would have been caught by Option Strict On -- check out the accepted answer. This is a quirk of the string-to-integer conversion rules which predate nullable types, but still impact them.

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  • QObject::connect not connecting signal to slot

    - by user1662800
    I am using C++ and Qt in my project and my problem is QObject::connect function doesn't connect signal to a slot. I have the following classes: class AddCommentDialog : public QDialog { Q_OBJECT public: ...some functions signals: void snippetAdded(); private slots: void on_buttonEkle_clicked(); private: Ui::AddCommentDialog *ui; QString snippet; }; A part of my Main window: class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); ~MainWindow(); private slots: void commentAddedSlot(); void variableAddedSlot(); ... private: AddCommentDialog *addCommentDialog; ... }; Ant the last dialog; class AddDegiskenDialog : public QDialog { Q_OBJECT public: ... signals: void variableAdded(); private slots: void on_buttonEkle_clicked(); private: Ui::AddDegiskenDialog *ui; ... }; In the main window constructor i connect signals and slots: addCommentDialog=new AddCommentDialog(); addDegiskenDialog=new AddDegiskenDialog(); connect(addDegiskenDialog, SIGNAL(variableAdded()), this, SLOT(variableAddedSlot())); connect(addCommentDialog, SIGNAL(snippetAdded()), this, SLOT(commentAddedSlot())); The point is my commentAddedSlot is connected to it's signal successfully, but commentAddedSlot is failed. There is the Q_OBJECT macros, no warning such as about no x slot. In addition to this, receivers(SIGNAL(snippetAdded())) gives me 1 but receivers(SIGNAL(variableAdded())) gives me 0 and i used commands qmake -project; qmake and make to fully compile. What am i missing?

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  • Scala implicit dynamic casting

    - by weakwire
    I whould like to create a scala Views helper for Android Using this combination of trait and class class ScalaView(view: View) { def onClick(action: View => Any) = view.setOnClickListener(new OnClickListener { def onClick(view: View) { action(view) } }) } trait ScalaViewTrait { implicit def view2ScalaView(view: View) = new ScalaView(view) } I'm able to write onClick() like so class MainActivity extends Activity with ScalaViewTrait { //.... val textView = new TextView(this) textView.onClick(v => v.asInstanceOf[TextView] setText ("asdas")) } My concern is that i want to avoid casting v to TextView v will always be TextView if is applied to a TextView LinearLayout if applied to LinearLayout and so on. Is there any way that v gets dynamic casted to whatever view is applied? Just started with Scala and i need your help with this. UPDATE With the help of generics the above get's like this class ScalaView[T](view: View) { def onClick(action: T => Any) = view.setOnClickListener(new OnClickListener { def onClick(view: View) { action(view.asInstanceOf[T]) } }) } trait ScalaViewTrait { implicit def view2ScalaView[T](view: View) = new ScalaView[T](view) } i can write onClick like this view2ScalaView[TextView](textView) .onClick(v => v.setText("asdas")) but is obvious that i don't have any help from explicit and i moved the problem instead or removing it

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  • Casting Type array to Generic array?

    - by George R
    The short version of the question - why can't I do this? I'm restricted to .NET 3.5. T[] genericArray; // Obviously T should be float! genericArray = new T[3]{ 1.0f, 2.0f, 0.0f }; // Can't do this either, why the hell not genericArray = new float[3]{ 1.0f, 2.0f, 0.0f }; Longer version - I'm working with the Unity engine here, although that's not important. What is - I'm trying to throw conversion between its fixed Vector2 (2 floats) and Vector3 (3 floats) and my generic Vector< class. I can't cast types directly to a generic array. using UnityEngine; public struct Vector { private readonly T[] _axes; #region Constructors public Vector(int axisCount) { this._axes = new T[axisCount]; } public Vector(T x, T y) { this._axes = new T[2] { x, y }; } public Vector(T x, T y, T z) { this._axes = new T[3]{x, y, z}; } public Vector(Vector2 vector2) { // This doesn't work this._axes = new T[2] { vector2.x, vector2.y }; } public Vector(Vector3 vector3) { // Nor does this this._axes = new T[3] { vector3.x, vector3.y, vector3.z }; } #endregion #region Properties public T this[int i] { get { return _axes[i]; } set { _axes[i] = value; } } public T X { get { return _axes[0];} set { _axes[0] = value; } } public T Y { get { return _axes[1]; } set { _axes[1] = value; } } public T Z { get { return this._axes.Length (Vector2 vector2) { Vector vector = new Vector(vector2); return vector; } public static explicit operator Vector(Vector3 vector3) { Vector vector = new Vector(vector3); return vector; } #endregion }

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  • Performance of a get unique elements/group by operation on an IEnumerable<T>.

    - by tolism7
    I was wondering how could I improve the performance of the following code: public class MyObject { public int Year { get; set; } } //In my case I have 30000 IEnumerable<MyObject> data = MethodThatReturnsManyMyObjects(); var groupedByYear = data.GroupBy(x => x.Year); //Here is the where it takes around 5 seconds foreach (var group in groupedByYear) //do something here. The idea is to get a set of objects with unique year values. In my scenario there are only 6 years included in the 30000 items in the list so the foreach loop will be executed 6 times only. So we have many items needing to be grouped in a few groups. Using the .Distinct() with an explicit IEqualityComparer would be an alternative but somehow I feel that it wont make any difference. I can understand if 30000 items is too much and that i should be happy with the 5 seconds I get, but I was wondering if the above can be imporved performance wise. Thanks.

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  • Breaking dependencies when you can't make changes to other files?

    - by codemuncher
    I'm doing some stealth agile development on a project. The lead programmer sees unit testing, refactoring, etc as a waste of resources and there is no way to convince him otherwise. His philosophy is "If it ain't broke don't fix it" and I understand his point of view. He's been working on the project for over a decade and knows the code inside and out. I'm not looking to debate development practices. I'm new to the project and I've been tasked with adding a new feature. I've worked on legacy projects before and used agile development practices with good result but those teams were more receptive to the idea and weren't afraid of making changes to code. I've been told I can use whatever development methodology I want but I have to limit my changes to only those necessary to add the feature. I'm using tdd for the new classes I'm writing but I keep running into road blocks caused by the liberal use of global variables and the high coupling in the classes I need to interact with. Normally I'd start extracting interfaces for these classes and make their dependence on the global variables explicit by injecting them as constructor arguments or public properties. I could argue that the changes are necessary but considering the lead never had to make them I doubt he would see it my way. What techniques can I use to break these dependencies without ruffling the lead developer's feathers? I've made some headway using: Extract Interface (for the new classes I'm creating) Extend and override the wayward classes with test stubs. (luckily most methods are public virtual) But these two can only get me so far.

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  • Heroku: Postgres type operator error after migrating DB from MySQL

    - by sevennineteen
    This is a follow-up to a question I'd asked earlier which phrased this as more of a programming problem than a database problem. http://stackoverflow.com/questions/2935985/postgres-error-with-sinatra-haml-datamapper-on-heroku I believe the problem has been isolated to the storage of the ID column in Heroku's Postgres database after running db:push. In short, my app runs properly on my original MySQL database, but throws Postgres errors on Heroku when executing any query on the ID column, which seems to have been stored in Postgres as TEXT even though it is stored as INT in MySQL. My question is why the ID column is being created as INT in Postgres on the data transfer to Heroku, and whether there's any way for me to prevent this. Here's the output from a heroku console session which demonstrates the issue: Ruby console for myapp.heroku.com >> Post.first.title => "Welcome to First!" >> Post.first.title.class => String >> Post.first.id => 1 >> Post.first.id.class => Fixnum >> Post[1] PostgresError: ERROR: operator does not exist: text = integer LINE 1: ...", "title", "created_at" FROM "posts" WHERE ("id" = 1) ORDER... ^ HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts. Query: SELECT "id", "name", "email", "url", "title", "created_at" FROM "posts" WHERE ("id" = 1) ORDER BY "id" LIMIT 1 Thanks!

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  • Online job-searching is tedious. Help me automate it.

    - by ehsanul
    Many job sites have broken searches that don't let you narrow down jobs by experience level. Even when they do, it's usually wrong. This requires you to wade through hundreds of postings that you can't apply for before finding a relevant one, quite tedious. Since I'd rather focus on writing cover letters etc., I want to write a program to look through a large number of postings, and save the URLs of just those jobs that don't require years of experience. I don't require help writing the scraper to get the html bodies of possibly relevant job posts. The issue is accurately detecting the level of experience required for the job. This should not be too difficult as job posts are usually very explicit about this ("must have 5 years experience in..."), but there may be some issues with overly simple solutions. In my case, I'm looking for entry-level positions. Often they don't say "entry-level", but inclusion of the words probably means the job should be saved. Next, I can safely exclude a job the says it requires "5 years" of experience in whatever, so a regex like /\d\syears/ seems reasonable to exclude jobs. But then, I realized some jobs say they'll take 0-2 years of experience, matches the exclusion regex but is clearly a job I want to take a look at. Hmmm, I can handle that with another regex. But some say "less than 2 years" or "fewer than 2 years". Can handle that too, but it makes me wonder what other patterns I'm not thinking of, and possibly excluding many jobs. That's what brings me here, to find a better way to do this than regexes, if there is one. I'd like to minimize the false negative rate and save all the jobs that seem like they might not require many years of experience. Does excluding anything that matches /[3-9]\syears|1\d\syears/ seem reasonable? Or is there a better way? Training a bayesian filter maybe?

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  • Big-O for GPS data

    - by HH
    A non-critical GPS module use lists because it needs to be modifiable, new routes added, new distances calculated, continuos comparisons. Well so I thought but my team member wrote something I am very hard to get into. His pseudo code int k =0; a[][] <- create mapModuleNearbyDotList -array //CPU O(n) for(j = 1 to n) // O(nlog(m)) for(i =1 to n) for(k = 1 to n) if(dot is nearby) adj[i][j]=min(adj[i][j], adj[i][k] + adj[k][j]); His ideas transformations of lists to tables His worst case time complexity is O(n^3), where n is number of elements in his so-called table. Exception to the last point with Finite structure: O(mlog(n)) where n is number of vertices and m is an arbitrary constants Questions about his ideas why to waste resources to transform constantly-modified lists to table? Fast? only point where I to some extent agree but cannot understand the same upper limits n for each for-loops -- perhaps he supposed it circular why does the code take O(mlog(n)) to proceed in time as finite structure? The term finite may be wrong, explicit?

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  • What is the rationale to not allow overloading of C++ conversions operator with non-member function

    - by Vicente Botet Escriba
    C++0x has added explicit conversion operators, but they must always be defined as members of the Source class. The same applies to the assignment operator, it must be defined on the Target class. When the Source and Target classes of the needed conversion are independent of each other, neither the Source can define a conversion operator, neither the Target can define a constructor from a Source. Usually we get it by defining a specific function such as Target ConvertToTarget(Source& v); If C++0x allowed to overload conversion operator by non member functions we could for example define the conversion implicitly or explicitly between unrelated types. template < typename To, typename From > operator To(const From& val); For example we could specialize the conversion from chrono::time_point to posix_time::ptime as follows template < class Clock, class Duration> operator boost::posix_time::ptime( const boost::chrono::time_point<Clock, Duration>& from) { using namespace boost; typedef chrono::time_point<Clock, Duration> time_point_t; typedef chrono::nanoseconds duration_t; typedef duration_t::rep rep_t; rep_t d = chrono::duration_cast<duration_t>( from.time_since_epoch()).count(); rep_t sec = d/1000000000; rep_t nsec = d%1000000000; return posix_time::from_time_t(0)+ posix_time::seconds(static_cast<long>(sec))+ posix_time::nanoseconds(nsec); } And use the conversion as any other conversion. For a more complete description of the problem, see here or on my Boost.Conversion library.. So the question is: What is the rationale to non allow overloading of C++ conversions operator with non-member functions?

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  • How can I create a DOTNET COM interop assembly for Classic ASP that does not sequentially block othe

    - by Alex Waddell
    Setup -- Create a simple COM addin through DOTNET/C# that does nothing but sleep on the current thread for 5 seconds. namespace ComTest { [ComVisible(true)] [ProgId("ComTester.Tester")] [Guid("D4D0BF9C-C169-4e5f-B28B-AFA194B29340")] [ClassInterface(ClassInterfaceType.AutoDual)] public class Tester { [STAThread()] public string Test() { System.Threading.Thread.Sleep(5000); return DateTime.Now.ToString(); } } } From an ASP page, call the test component: <%@ Language=VBScript %> <%option explicit%> <%response.Buffer=false%> <% dim test set test = CreateObject("ComTester.Tester") %> <HTML> <HEAD></HEAD> <BODY> <% Response.Write(test.Test()) set test = nothing %> </BODY> </HTML> When run on a windows 2003 server, the test.asp page blocks ALL OTHER threads in the site while the COM components sleeps. How can I create a COM component for ASP that does not block all ASP worker threads?

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  • Which isolation level should I use for the following insert-if-not-present transaction?

    - by Steve Guidi
    I've written a linq-to-sql program that essentially performs an ETL task, and I've noticed many places where parallelization will improve its performance. However, I'm concerned about preventing uniquness constraint violations when two threads perform the following task (psuedo code). Record CreateRecord(string recordText) { using (MyDataContext database = GetDatabase()) { Record existingRecord = database.MyTable.FirstOrDefault(record.KeyPredicate()); if(existingRecord == null) { existingRecord = CreateRecord(recordText); database.MyTable.InsertOnSubmit(existingRecord); } database.SubmitChanges(); return existingRecord; } } In general, this code executes a SELECT statement to test for record existance, followed by an INSERT statement if the record doesn't exist. It is encapsulated by an implicit transaction. When two threads run this code for the same instance of recordText, I want to prevent them from simultaneously determining that the record doesn't exist, thereby both attempting to create the same record. An isolation level and explicit transaction will work well, except I'm not certain which isolation level I should use -- Serializable should work, but seems too strict. Is there a better choice?

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  • Argument type deduction, references and rvalues

    - by uj2
    Consider the situation where a function template needs to forward an argument while keeping it's lvalue-ness in case it's a non-const lvalue, but is itself agnostic to what the argument actually is, as in: template <typename T> void target(T&) { cout << "non-const lvalue"; } template <typename T> void target(const T&) { cout << "const lvalue or rvalue"; } template <typename T> void forward(T& x) { target(x); } When x is an rvalue, instead of T being deduced to a constant type, it gives an error: int x = 0; const int y = 0; forward(x); // T = int forward(y); // T = const int forward(0); // Hopefully, T = const int, but actually an error forward<const int>(0); // Works, T = const int It seems that for forward to handle rvalues (without calling for explicit template arguments) there needs to be an forward(const T&) overload, even though it's body would be an exact duplicate. Is there any way to avoid this duplication?

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  • Code Analysis Warning CA1004 with generic method

    - by Vaccano
    I have the following generic method: // Load an object from the disk public static T DeserializeObject<T>(String filename) where T : class { XmlSerializer xmlSerializer = new XmlSerializer(typeof(T)); try { TextReader textReader = new StreamReader(filename); var result = (T)xmlSerializer.Deserialize(textReader); textReader.Close(); return result; } catch (FileNotFoundException) { } return null; } When I compile I get the following warning: CA1004 : Microsoft.Design : Consider a design where 'MiscHelpers.DeserializeObject(string)' doesn't require explicit type parameter 'T' in any call to it. I have considered this and I don't know a way to do what it requests with out limiting the types that can be deserialized. I freely admit that I might be missing an easy way to fix this. But if I am not, then is my only recourse to suppress this warning? I have a clean project with no warnings or messages. I would like to keep it that way. I guess I am asking "why this is a warning?" At best this seems like it should be a message. And even that seems a bit much. Either it can or it can't be fixed. If it can't then you are just stuck with the warning with no recourse but suppressing it. Am I wrong?

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  • File mkdirs() method not working in android/java

    - by Leif Andersen
    I've been pulling out my hair on this for a while now. The following method is supposed to download a file, and save it to the location specified on the hard drive. private static void saveImage(Context context, boolean backgroundUpdate, URL url, File file) { if (!Tools.checkNetworkState(context, backgroundUpdate)) return; // Get the image try { // Make the file file.getParentFile().mkdirs(); // Set up the connection URLConnection uCon = url.openConnection(); InputStream is = uCon.getInputStream(); BufferedInputStream bis = new BufferedInputStream(is); // Download the data ByteArrayBuffer baf = new ByteArrayBuffer(50); int current = 0; while ((current = bis.read()) != -1) { baf.append((byte) current); } // Write the bits to the file OutputStream os = new FileOutputStream(file); os.write(baf.toByteArray()); os.close(); } catch (Exception e) { // Any exception is probably a newtork faiilure, bail return; } } Also, if the file doesn't exist, it is supposed to make the directory for the file. (And if there is another file already in that spot, it should just not do anything). However, for some reason, the mkdirs() method never makes the directory. I've tried everything from explicit parentheses, to explicitly making the parent file class, and nothing seems to work. I'm fairly certain that the drive is writable, as it's only called after that has already been determined, also that is true after running through it while debugging. So the method fails because the parent directories aren't made. Can anyone tell me if there is anything wrong with the way I'm calling it? Also, if it helps, here is the source for the file I'm calling it in: https://github.com/LeifAndersen/NetCatch/blob/master/src/net/leifandersen/mobile/android/netcatch/services/RSSService.java Thank you

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  • Error using to_char // to_timetamp

    - by pepersview
    Hello, I have a database in PostgreSQL and I'm developing an application in PHP using this database. The problem is that when I execute the following query I get a nice result in phpPgAdmin but in my PHP application I get an error. The query: SELECT t.t_name, t.t_firstname FROM teachers AS t WHERE t.id_teacher IN (SELECT id_teacher FROM teacher_course AS tcourse JOIN course_timetable AS coursetime ON tcourse.course = coursetime.course AND to_char(to_timestamp('2010-4-12', 'YYYY-MM-DD'),'FMD') = (coursetime.day +1)) AND t.id_teacher NOT IN (SELECT id_teacher FROM teachers_fill WHERE date = '2010-4-12') ORDER BY t.t_name ASC And this is the error in PHP operator does not exist: text = integer (to_timestamp('', 'YYYY-MM-DD'),'FMD') = (courset... ^ HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts. The purpose to solve this error is to use the ORIGINAL query in php with : $date = "2010"."-".$selected_month."-".$selected_day; SELECT t.t_name, t.t_firstname FROM teachers AS t WHERE t.id_teacher IN (SELECT id_teacher FROM teacher_course AS tcourse JOIN course_timetable AS coursetime ON tcourse.course = coursetime.course AND to_char(to_timestamp('$date', 'YYYY-MM-DD'),'FMD') = (coursetime.day +1)) AND t.id_teacher NOT IN (SELECT id_teacher FROM teachers_fill WHERE date = '$date') ORDER BY t.t_name ASC

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  • How to take a collection of bytes and pull typed values out of it?

    - by Pat
    Say I have a collection of bytes var bytes = new byte[] {0, 1, 2, 3, 4, 5, 6, 7}; and I want to pull out a defined value from the bytes as a managed type, e.g. a ushort. What is a simple way to define what types reside at what location in the collection and pull out those values? One (ugly) way is to use System.BitConverter and a Queue or byte[] with an index and simply iterate through, e.g.: int index = 0; ushort first = System.BitConverter.ToUint16(bytes, index); index += 2; // size of a ushort int second = System.BitConverter.ToInt32(bytes, index); index += 4; ... This method gets very, very tedious when you deal with a lot of these structures! I know that there is the System.Runtime.InteropServices.StructLayoutAttribute which allows me to define the locations of types inside a struct or class, but there doesn't seem to be a way to import the collection of bytes into that struct. If I could somehow overlay the struct on the collection of bytes and pull out the values, that would be ideal. E.g. Foo foo = (Foo)bytes; // doesn't work because I'd need to implement the implicit operator ushort first = foo.first; int second = foo.second; ... [StructLayout(LayoutKind.Explicit, Size=FOO_SIZE)] public struct Foo { [FieldOffset(0)] public ushort first; [FieldOffset(2)] public int second; } Any thoughts on how to achieve this?

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  • odd url, and difficulty in following the php page flow

    - by sdfor
    I'm trying to understand code that I bought so I can modify it. In the index.php there are picture links: <a href="test10,10"><img title="" border=1 src="makethumb.php?pic=product_images/test101.jpg&amp;w=121&amp;sq=N" / ></a> I don't understand the href since it is not pointing to a page. test10 is an id of a picture. I assumed it was going back to the index.php and the code would extract the test10,10 from the url, but it's not. I know that because I put in trace code as the first line. The question is, where is the link going to? I know it that it somewhere in the process it executes a page called profile.php, but nowhere in the source code (doing a global search) is there an explicit call to profile.php. As a related question, is there a way to profile the code to see what pages it's calling without using xdebug, which for the life of me I can't get working after many hours of trying every suggestion I found here and else where. (I'm using xampp) thanks

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