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• Error trying to run rails server

  - by David87

  I am trying to get a basic Rails application to run on my Mac OS X 10.6.5. I created a new app called demo (rails new demo), then went into the demo directory and tried to start the app with rails server. Here is the error message I received: "/Users/dpetrovi/.gem/ruby/1.8/gems/sqlite3-ruby-1.3.2/lib/sqlite3/sqlite3_native.bundle: [BUG] Segmentation fault ruby 1.8.7 (2010-12-23 patchlevel 330) [i686-darwin10] Abort trap" I checked bundle install in the demo folder: "Using rake (0.8.7) Using abstract (1.0.0) Using activesupport (3.0.3) Using builder (2.1.2) Using i18n (0.5.0) Using activemodel (3.0.3) Using erubis (2.6.6) Using rack (1.2.1) Using rack-mount (0.6.13) Using rack-test (0.5.6) Using tzinfo (0.3.23) Using actionpack (3.0.3) Using mime-types (1.16) Using polyglot (0.3.1) Using treetop (1.4.9) Using mail (2.2.13) Using actionmailer (3.0.3) Using arel (2.0.6) Using activerecord (3.0.3) Using activeresource (3.0.3) Using bundler (1.0.7) Using thor (0.14.6) Using railties (3.0.3) Using rails (3.0.3) Using sqlite3-ruby (1.3.2) Your bundle is complete! Use bundle show [gemname] to see where a bundled gem is installed." Ruby, RubyGems, and sqlite3 were installed using MacPorts. Then I used gem to try to install the sqlite3-ruby interface. (sudo gem install sqlite3-ruby). Here is where I first noticed something could be off: "Successfully installed sqlite3-ruby-1.3.2 1 gem installed Installing ri documentation for sqlite3-ruby-1.3.2... No definition for libversion Enclosing class/module 'mSqlite3' for class Statement not known Installing RDoc documentation for sqlite3-ruby-1.3.2... No definition for libversion Enclosing class/module 'mSqlite3' for class Statement not known " I had rails running well on my system a few months ago, so I figured maybe I had some duplicates and it was trying to use the wrong one. I ran: "for cmd in ruby irb gem rake; do which $cmd; done" and got: "/opt/local/bin/ruby /opt/local/bin/irb /opt/local/bin/gem /opt/local/bin/rake" Checking where sqlite3 also gets me: "/opt/local/bin/sqlite3" so they all seem to be in the right place. Obviously /opt/local/bin is in my system path. If I check gems server, it shows that I have installed sqlite3-ruby 1.3.2 gem. Not sure what the problem could be? I am using ruby 1.8.7 (2010-12-23 patchlevel 330) [i686-darwin10]. Macports claims this is the latest (although ive seen 1.9.1) One more thing-- in irb, I tried to check which version of sqlite3 my sqlite3-ruby is bound to, but I can only get this far: ":irb(main):001:0 require 'rubygems' = true irb(main):002:0 require 'sqlite3' /Users/dpetrovi/.gem/ruby/1.8/gems/sqlite3-ruby-1.3.2/lib/sqlite3/sqlite3_native.bundle: [BUG] Segmentation fault ruby 1.8.7 (2010-12-23 patchlevel 330) [i686-darwin10] Abort trap" Any suggestions? Im hoping I overlooked something obvious. Thanks

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• c#: Design advice. Using DataTable or List<MyObject> for a generic rule checker

  - by Andrew White

  Hi, I have about 100,000 lines of generic data. Columns/Properties of this data are user definable and are of the usual data types (string, int, double, date). There will be about 50 columns/properties. I have 2 needs: To be able to calculate new columns/properties using an expression e.g. Column3 = Column1 * Column2. Ultimately I would like to be able to use external data using a callback, e.g. Column3 = Column1 * GetTemperature The expression is relatively simple, maths operations, sum, count & IF are the only necessary functions. To be able to filter/group the data and perform aggregations e.g. Sum(Data.Column1) Where(Data.Column2 == "blah") As far as I can see I have two options: 1. Using a DataTable. = Point 1 above is achieved by using DataColumn.Expression = Point 2 above is acheived by using DataTable.DefaultView.RowFilter & C# code 2. Using a List of generic Objects each with a Dictionary< string, object to store the values. = Point 1 could be achieved by something like NCalc = Point 2 is achieved using LINQ DataTable: Pros: DataColumn.Expression is inbuilt Cons: RowFilter & coding c# is not as "nice" as LINQ, DataColumn.Expression does not support callbacks(?) = workaround could be to get & replace external value when creating the calculated column GenericList: Pros: LINQ syntax, NCalc supports callbacks Cons: Implementing NCalc/generic calc engine Based on the above I would think a GenericList approach would win, but something I have not factored in is the performance which for some reason I think would be better with a datatable. Does anyone have a gut feeling / experience with LINQ vs. DataTable performance? How about NCalc? As I said there are about 100,000 rows of data, with 50 columns, of which maybe 20 are calculated. In total about 50 rules will be run against the data, so in total there will be 5 million row/object scans. Would really appreciate any insights. Thx. ps. Of course using a database + SQL & Views etc. would be the easiest solution, but for various reasons can't be implemented.

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• passing custom object as parameter to a webmethod of asp.net web service

  - by Jon

  Hi, I have a custom class declared as follows (in vb.net) <Serializable()> _ Public Class NumInfo Public n As String Public f As Integer Public fc As char() Public t As Integer Public tc As char() Private validFlag As Boolean = True Public Sub New() End Sub 'I also have public properties(read/write) for all the public variablesEnd Class In my service.asmx codebehind class I have a webmethod as follows: <WebMethod()> _ <XmlInclude(GetType(NumInfo))> _ Public Function ConvertTo(ByVal info As NumInfo) As String Return mbc(info)'mbc is another function defined in my service.asmx "service" class End Function The problem is that when I start debugging it to test it, the page that I get does not contain any fields where I could input the values for the public fields of numInfo. How do I initialise the class? There is no "Invoke" button either. All I see are soap details as below: ConvertToTestThe test form is only available for methods with primitive types as parameters.SOAP 1.1The following is a sample SOAP 1.1 request and response. The placeholders shown need to be replaced with actual values.POST /Converter/BC.asmx HTTP/1.1Host: localhostContent-Type: text/xml; charset=utf-8Content-Length: lengthSOAPAction: "http://Services/ConvertTo"<?xml version="1.0" encoding="utf-8"?> <soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <ConvertTo xmlns="http://Services/"> <info> <n>string</n> <f>int&lt/f> <fc> <char>char</char> <char>char>/char> </fc>..etc.. What am I doing wrong? For the record I tried replacing char() with string to see if it was the array causing problems but that didn't help either. I'm fairly new to web services. I tried replacing the custom object parameter with a primitive parameter just to check how things worked and it rendered a page with an input field and invoke button. I just can't seem to get it working with custom object. Help!

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• Can you pass by reference in Java?

  - by dbones

  Hi. Sorry if this sounds like a newbie question, but the other day a Java developer mentioned about passing a paramter by reference (by which it was ment just pass a Reference object) From a C# perspective I can pass a reference type by value or by reference, this is also true to value types I have written a noddie console application to show what i mean.. can i do this in Java? namespace ByRefByVal { class Program { static void Main(string[] args) { //Creating of the object Person p1 = new Person(); p1.Name = "Dave"; PrintIfObjectIsNull(p1); //should not be null //A copy of the Reference is made and sent to the method PrintUserNameByValue(p1); PrintIfObjectIsNull(p1); //the actual reference is passed to the method PrintUserNameByRef(ref p1); //<-- I know im passing the Reference PrintIfObjectIsNull(p1); Console.ReadLine(); } private static void PrintIfObjectIsNull(Object o) { if (o == null) { Console.WriteLine("object is null"); } else { Console.WriteLine("object still references something"); } } /// <summary> /// this takes in a Reference type of Person, by value /// </summary> /// <param name="person"></param> private static void PrintUserNameByValue(Person person) { Console.WriteLine(person.Name); person = null; //<- this cannot affect the orginal reference, as it was passed in by value. } /// <summary> /// this takes in a Reference type of Person, by reference /// </summary> /// <param name="person"></param> private static void PrintUserNameByRef(ref Person person) { Console.WriteLine(person.Name); person = null; //this has access to the orginonal reference, allowing us to alter it, either make it point to a different object or to nothing. } } class Person { public string Name { get; set; } } } If it java cannot do this, then its just passing a reference type by value? (is that fair to say) Many thanks Bones

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• Stuck on an ASP.NET/WCF WSDL Parsing Error

  - by Vaccano

  I have a WCF Web Service that my ASP.NET app uses. It has been working fine for quite some time. I just added in a Dev Express Grid (and the Dev Express DLLs) and a new page that uses them and now I am getting parsing errors on the WSDL. But the weird part is that it works fine on my machine but fails on the web server machine. (Both are connecting to the same web services WSDL.) Here is the error message I am getting: Server Error in '/MyWebAppWebDev' Application. -------------------------------------------------------------------------------- Parser Error Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately. Parser Error Message: Reference.svcmap: Failed to generate code for the service reference 'MyWebAppService'. Cannot import wsdl:portType Detail: An exception was thrown while running a WSDL import extension: System.ServiceModel.Description.DataContractSerializerMessageContractImporter Error: Referenced type 'WebClientApp.MyWebAppService.ReferenceUpdatesDataContract, WebClientApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' with data contract name 'ReferenceUpdatesDataContract' in namespace 'http://schemas.datacontract.org/2004/07/MyWebAppServiceLibrary.DataContracts' cannot be used since it does not match imported DataContract. Need to exclude this type from referenced types. XPath to Error Source: //wsdl:definitions[@targetNamespace='http://tempuri.org/']/wsdl:portType[@name='IMyWebAppReferenceDataServiceLib'] Cannot import wsdl:binding Detail: There was an error importing a wsdl:portType that the wsdl:binding is dependent on. XPath to wsdl:portType: //wsdl:definitions[@targetNamespace='http://tempuri.org/']/wsdl:portType[@name='IMyWebAppReferenceDataServiceLib'] XPath to Error Source: //wsdl:definitions[@targetNamespace='http://tempuri.org/']/wsdl:binding[@name='MyWebAppServicesDefaultEndpoint'] Cannot import wsdl:port Detail: There was an error importing a wsdl:binding that the wsdl:port is dependent on. XPath to wsdl:binding: //wsdl:definitions[@targetNamespace='http://tempuri.org/']/wsdl:binding[@name='MyWebAppServicesDefaultEndpoint'] XPath to Error Source: //wsdl:definitions[@targetNamespace='http://tempuri.org/']/wsdl:service[@name='MyWebAppReferenceDataServiceLib']/wsdl:port[@name='MyWebAppServicesDefaultEndpoint'] Source Error: [No relevant source lines] Source File: /MyWebAppWebDev/App_WebReferences/MyWebAppService/ Line: 1 I am completely stumped on this. I have checked my web.config endpoint address and it is spot on (and notably is not in the error message above). Any ideas would be welcomed. Things I have tried: Giving permissions to C:\Windows\temp to my Website user name Giving permissions to C:\Windows\temp to my App pool user name Checking to see that none of my data contracts are generic and have IsReference=true in them.

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• Create class instance in assembly from string name

  - by Arcadian

  I'm not sure if this is possible, and I'm quite new to using assemblies in C#.NET. What I would like to do is to create an instance of a class when supplied the string name of that class. Something like this: using MyAssembly; namespace MyNameSpace { Class MyClass { int MyValue1; int MyValue2; public MyClass(string myTypeName) { foreach(Type type in MyAssembly) { if((string)type == myTypeName) { //create a new instance of the type } } AssignInitialValues(//the type created above) } //Here I use an abstract type which the type above inherits from private void AssignInitialValues(AbstractType myClass) { this.value1 = myClass.value1; this.value2 = myClass.value2; } } } Obviously you cannot compare strings to types but it illustrates what I'm trying to do: create a type from a supplied string. Any thoughts? EDIT: After attempting: var myObject = (AbstractType) Activator.CreateInstance(null, myTypeName); AssignInitialValues(myObject); I get a number of errors: Inconsistent accessibility: parameter type 'MyAssembly.AbstractType' is less accessible than method 'MyNameSpace.MyClass.AssignInitialValues(MyAssembly.AstractType)' 'MyAssembly.AstractType' is inaccessible due to it's protection level The type or namespace name 'MyAssembly' could not be found (are you missing a using directive or an assembly reference?) The type or namespace name 'AbstractType' could not be found (are you missing a using directive or an assembly reference?) Not exactly sure why it can't find the assembly; I've added a reference to the assembly and I use a Using Directive for the namespace in the assembly. As for the protection level, it's calling classes (or rather the constructors of classes) which can only be public. Any clues on where the problem is? UPDATE: After looking through several articles on SO I came across this: http://stackoverflow.com/a/1632609/360627 Making the AbstractTypeclass public solved the issue of inconsistent accessibility. The new compiler error is this: Cannot convert type 'System.Runtime.Remoting.ObjectHandle' to 'MyAssembly.AbstractType' The line it references is this one: var myObject = (AbstractType) Activator.CreateInstance(null, myTypeName); Using .Unwrap() get's me past this error and I think it's the right way to do it (uncertain). However, when running the program I then get a TypeLoadException when this code is called. TypeLoadException: Could not load type ‘AbstractType’ from assembly ‘MyNameSpace'... Right away I can spot that the type its looking for is correct but the assembly it's looking in is wrong. Looking up the Activator.CreateInstance(String, String) method revealed that the null as the first argument means that the method will look in the executing assembly. This is contrary to the required behavior as in the original post. I've tried using MyAssembly as the first argument but this produces the error: 'MyAssembly' is a 'namespace' but is used like a 'variable' Any thoughts on how to fix this?

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• DRUPAL probl [tid] field : in View how to link Taxonomy term to MY view (and not to taxonomy/term)

  - by davezen

  SUMMARY : I have a view where I need to replace the term link "taxonomy/term" by my view link, because the view uses arguments to find content with terms how can I put in link argument the term which is display : [term_name1] link "display_view/term_name1", [term_name2] link "display_view/term_name2" I used [tid] field to put argument in link display_view/[tid] but it only display the first term, and not the real term (for example if multiple taggs it only display the first) and put all the terms in one single link : [term_name1 term_name2] link "display_view/term_name1" so why [tid] or [tid_1] don't run ? is there another field, or do I need php ? really need help ! :) DESCRIPTION : Hello, I made a view table to display store content it display : user name, title, taxonomy term to type (book, disc...), taxonomy term for taggs (subject of objects) for example : USER | TITLE | TERM TYPE (only one) | TERM SUBJECTS (taggs) user1 | James Brown disc | disc | soul jamesbrown user2 | rolls book | book | cars rolls travel so I display different types of terms and in subjects it can have a multiple because it's taggs I use arguments so it can have display for example only store from an user, or from an taxonomy (for examples only the disc, or the disc about soul) so I can link display_view/argtermtype/argtermsubject (I separate the type and subject) MY NEED : what i want is the terms of the view don't redirect on taxonomy/term but on my view so I have to : change the link of terms in view to redirect on display_texts/all/all replace [all] with the [term] argument MY PROBLEM : I can't have the right field of terms displayed in the links of terms in fields, I : checked "Output this field as a link" put the link "display_view/[tid]" for term type and "display_view/all/[tid]" for term subjects NOT checked "Link this field to its term page" what it does : [tid] put in link FOR ALL THE LINE the SAME TERM and it put all the terms in one single link ! that's to say, it creates the links : USER | TITLE | TERM TYPE (only one) | TERM SUBJECTS (taggs) user1 | James Brown disc| [disc] display_texts/disc (ok !) | [soul jamesbrown] (BAD only one link!) display_texts/all/disc (BAD it's not the new term !) what I need : USER | TITLE | TERM TYPE (only one) | TERM SUBJECTS (taggs) user1 | James Brown disc| [disc] display_texts/disc| [soul] display_texts/all/soul [jamesbrown] display_texts/all/jamesbrown) MY QUESTION : so how can I put in argument the term which is display ? I try things like [tid_1] but doesn't work is there any list of fields somewhere ? or do i have to use php code ? how to separate link terms ? if I check "Link this field to its term page" links are separate but it replace my link by "taxonomy/term" link think's in advance for any idea !

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• C++ vs. C++/CLI: Const qualification of virtual function parameters

  - by James McNellis

  [All of the following was tested using Visual Studio 2008 SP1] In C++, const qualification of parameter types does not affect the type of a function (8.3.5/3: "Any cv-qualifier modifying a parameter type is deleted") So, for example, in the following class hierarchy, Derived::Foo overrides Base::Foo: struct Base { virtual void Foo(const int i) { } }; struct Derived : Base { virtual void Foo(int i) { } }; Consider a similar hierarchy in C++/CLI: ref class Base abstract { public: virtual void Foo(const int) = 0; }; ref class Derived : public Base { public: virtual void Foo(int i) override { } }; If I then create an instance of Derived: int main(array<System::String ^> ^args) { Derived^ d = gcnew Derived; } it compiles without errors or warnings. When I run it, it throws the following exception and then terminates: An unhandled exception of type 'System.TypeLoadException' occurred in ClrVirtualTest.exe Additional information: Method 'Foo' in type 'Derived'...does not have an implementation. That exception seems to indicate that the const qualification of the parameter does affect the type of the function in C++/CLI (or, at least it affects overriding in some way). However, if I comment out the line containing the definition of Derived::Foo, the compiler reports the following error (on the line in main where the instance of Derived is instantiated): error C2259: 'Derived': cannot instantiate abstract class If I add the const qualifier to the parameter of Derived::Foo or remove the const qualifier from the parameter of Base::Foo, it compiles and runs with no errors. I would think that if the const qualification of the parameter affects the type of the function, I should get this error if the const qualification of the parameter in the derived class virtual function does not match the const qualification of the parameter in the base class virtual function. If I change the type of Derived::Foo's parameter from an int to a double, I get the following warning (in addition to the aforementioned error, C2259): warning C4490: 'override': incorrect use of override specifier; 'Derived::Foo' does not match a base ref class method So, my question is, effectively, does the const qualification of function parameters affect the type of the function in C++/CLI? If so, why does this compile and why are there no errors or warnings? If not, why is an exception thrown?

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• Serious Memory Clash: Variables clashing in C

  - by Soham

  int main(int argc, char*argv[]) { Message* newMessage; Asset* Check; //manipulation and initialization of Check, so that it holds proper values. newMessage = parser("N,2376,01/02/2011 09:15:01.342,JPASSOCIAT FUTSTK 24FEB2011,B,84.05,2000,0,0",newMessage); // MessageProcess(newMessage,AssetMap); printf("LAST TRADE ADDRESS %p LAST TRADE TIME %s\n",Check->TradeBook,Check->Time); } Message* parser(char *message,Message* new_Message) { char a[9][256]; char* tmp =message; bool inQuote=0; int counter=0; int counter2=0; new_Message = (Message*)malloc(sizeof(Message)); while(*tmp!='\0') { switch(*tmp) { case ',': if(!inQuote) { a[counter][counter2]='\0'; counter++; counter2=0; } break; case '"': inQuote=!inQuote; break; default: a[counter][counter2]=*tmp; counter2++; break; } tmp++; } a[counter][counter2]='\0'; new_Message->type = *a[0]; new_Message->Time = &a[2][11]; new_Message->asset = a[3]; if(*a[4]=='S') new_Message->BS = 0; else new_Message->BS = 1; new_Message->price1=atof(a[5]); new_Message->shares1=atol(a[6]); new_Message->price2=atof(a[7]); new_Message->shares2=atol(a[8]); new_Message->idNum = atoi(a[1]); return(new_Message); } Here there is a serious memory clash, in two variables of different scope. I have investigated using gdb and it seems the address of new_Message->Time is equalling to the address of Check->Time. They both are structures of different types I am trying to resolve this issue, because, when parser changes the value of new_Message->Time it manipulates the contents of Check-Time Please do suggest how to solve this problem. I have lost(spent) around 10 hours and counting to resolve this issue, and tons of hair. Soham

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• Rails 3 - development errors in production mode

  - by skrafi

  Im using Rails, Passenger (both are 3.0.5) and Nginx on my production server. As I heard, Rails should show public/404.html or public/500.html instead of development errors like ActiveRecord::RecordNotFound or Unknown action but that doesn't happen. I've tried to delete config.ru file and set rack_env or rails_env in nginx.conf but nothing helped. Here is my nginx.conf: worker_processes 1; events { worker_connections 1024; } http { passenger_root /home/makk/.rvm/gems/ruby-1.9.2-p0/gems/passenger-3.0.5; passenger_ruby /home/makk/.rvm/bin/passenger_ruby; #passenger_ruby /home/makk/.rvm/wrappers/ruby-1.9.2-p0/ruby; include mime.types; default_type application/octet-stream; sendfile on; keepalive_timeout 65; server { listen 80; server_name localhost; location / { root /home/makk/projects/1server/deploy/current/public; index index.html index.htm; passenger_enabled on; rack_env production; recursive_error_pages on; if (-f /home/makk/projects/1server/maintenance.html) { return 503; } error_page 404 /404.html; error_page 500 502 504 /500.html; error_page 503 @503; } location @503 { error_page 405 = /maintenance.html; # Serve static assets if found. if (-f $request_filename) { break; } rewrite ^(.*)$ /maintenance.html break; } location ~ ^(\/phpmyadmin\/)(.*)$ { fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; fastcgi_split_path_info ^(\/phpmyadmin\/)(.*)$; fastcgi_param SCRIPT_FILENAME /usr/share/phpmyadmin/$fastcgi_path_info; include fastcgi_params; } } } It seems that this question duplicates this one but there are no working suggestions. UPD: I have both development and production apps on same PC. In production Rails ignores config.consider_all_requests_local = false (in /config/environments/production.rb) due to local_request? method. So one of possible solutions is listed below (taken from here): # config/initializers/local_request_override.rb module CustomRescue def local_request? return false if Rails.env.production? || Rails.env.staging? super end end ActionController::Base.class_eval do include CustomRescue end Or for Rails 3: class ActionDispatch::Request def local? false end end

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• How do you prevent IDisposable from spreading to all your classes?

  - by GrahamS

  Start with these simple classes... Let's say I have a simple set of classes like this: class Bus { Driver busDriver = new Driver(); } class Driver { Shoe[] shoes = { new Shoe(), new Shoe() }; } class Shoe { Shoelace lace = new Shoelace(); } class Shoelace { bool tied = false; } A Bus has a Driver, the Driver has two Shoes, each Shoe has a Shoelace. All very silly. Add an IDisposable object to Shoelace Later I decide that some operation on the Shoelace could be multi-threaded, so I add an EventWaitHandle for the threads to communicate with. So Shoelace now looks like this: class Shoelace { private AutoResetEvent waitHandle = new AutoResetEvent(false); bool tied = false; // ... other stuff .. } Implement IDisposable on Shoelace Buit now FxCop will complain: "Implement IDisposable on 'Shoelace' because it creates members of the following IDisposable types: 'EventWaitHandle'." Okay, I implement IDisposable on Shoelace and my neat little class becomes this horrible mess: class Shoelace : IDisposable { private AutoResetEvent waitHandle = new AutoResetEvent(false); bool tied = false; private bool disposed = false; public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } ~Shoelace() { Dispose(false); } protected virtual void Dispose(bool disposing) { if (!this.disposed) { if (disposing) { if (waitHandle != null) { waitHandle.Close(); waitHandle = null; } } // No unmanaged resources to release otherwise they'd go here. } disposed = true; } } Or (as pointed out by commenters) since Shoelace itself has no unmanaged resources, I might use the simpler dispose implementation without needing the Dispose(bool) and Destructor: class Shoelace : IDisposable { private AutoResetEvent waitHandle = new AutoResetEvent(false); bool tied = false; public void Dispose() { if (waitHandle != null) { waitHandle.Close(); waitHandle = null; } GC.SuppressFinalize(this); } } Watch in horror as IDisposable spreads Right that's that fixed. But now FxCop will complain that Shoe creates a Shoelace, so Shoe must be IDisposable too. And Driver creates Shoe so Driver must be IDisposable. and Bus creates Driver so Bus must be IDisposable and so on. Suddenly my small change to Shoelace is causing me a lot of work and my boss is wondering why I need to checkout Bus to make a change to Shoelace. The Question How do you prevent this spread of IDisposable, but still ensure that your unmanaged objects are properly disposed?

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• C# Reading and Writing a Char[] to and from a Byte[]

  - by Simon G

  Hi, I have a byte array of around 10,000 bytes which is basically a blob from delphi that contains char, string, double and arrays of various types. This need to be read in and updated via C#. I've created a very basic reader that gets the byte array from the db and converts the bytes to the relevant object type when accessing the property which works fine. My problem is when I try to write to a specific char[] item, it doesn't seem to update the byte array. I've created the following extensions for reading and writing: public static class CharExtension { public static byte ToByte( this char c ) { return Convert.ToByte( c ); } public static byte ToByte( this char c, int position, byte[] blob ) { byte b = c.ToByte(); blob[position] = b; return b; } } public static class CharArrayExtension { public static byte[] ToByteArray( this char[] c ) { byte[] b = new byte[c.Length]; for ( int i = 1; i < c.Length; i++ ) { b[i] = c[i].ToByte(); } return b; } public static byte[] ToByteArray( this char[] c, int positon, int length, byte[] blob ) { byte[] b = c.ToByteArray(); Array.Copy( b, 0, blob, positon, length ); return b; } } public static class ByteExtension { public static char ToChar( this byte[] b, int position ) { return Convert.ToChar( b[position] ); } } public static class ByteArrayExtension { public static char[] ToCharArray( this byte[] b, int position, int length ) { char[] c = new char[length]; for ( int i = 0; i < length; i++ ) { c[i] = b.ToChar( position ); position += 1; } return c; } } to read and write chars and char arrays my code looks like: Byte[] _Blob; // set from a db field public char ubin { get { return _tariffBlob.ToChar( 14 ); } set { value.ToByte( 14, _Blob ); } } public char[] usercaplas { get { return _tariffBlob.ToCharArray( 2035, 10 ); } set { value.ToByteArray( 2035, 10, _Blob ); } } So to write to the objects I can do: ubin = 'C'; // this will update the byte[] usercaplas = new char[10] { 'A', 'B', etc. }; // this will update the byte[] usercaplas[3] = 'C'; // this does not update the byte[] I know the reason is that the setter property is not being called but I want to know is there a way around this using code similar to what I already have? I know a possible solution is to use a private variable called _usercaplas that I set and update as needed however as the byte array is nearly 10,000 bytes in length the class is already long and I would like a simpler approach as to reduce the overall code length and complexity. Thank

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• What's the standard algorithm for syncing two lists of objects?

  - by Oliver Giesen

  I'm pretty sure this must be in some kind of text book (or more likely in all of them) but I seem to be using the wrong keywords to search for it... :( A common task I'm facing while programming is that I am dealing with lists of objects from different sources which I need to keep in sync somehow. Typically there's some sort of "master list" e.g. returned by some external API and then a list of objects I create myself each of which corresponds to an object in the master list. Sometimes the nature of the external API will not allow me to do a live sync: For instance the external list might not implement notifications about items being added or removed or it might notify me but not give me a reference to the actual item that was added or removed. Furthermore, refreshing the external list might return a completely new set of instances even though they still represent the same information so simply storing references to the external objects might also not always be feasible. Another characteristic of the problem is that both lists cannot be sorted in any meaningful way. You should also assume that initializing new objects in the "slave list" is expensive, i.e. simply clearing and rebuilding it from scratch is not an option. So how would I typically tackle this? What's the name of the algorithm I should google for? In the past I have implemented this in various ways (see below for an example) but it always felt like there should be a cleaner and more efficient way. Here's an example approach: Iterate over the master list Look up each item in the "slave list" Add items that do not yet exist Somehow keep track of items that already exist in both lists (e.g. by tagging them or keeping yet another list) When done iterate once more over the slave list Remove all objects that have not been tagged (see 4.) Update Thanks for all your responses so far! I will need some time to look at the links. Maybe one more thing worthy of note: In many of the situations where I needed this the implementation of the "master list" is completely hidden from me. In the most extreme cases the only access I might have to the master list might be a COM-interface that exposes nothing but GetFirst-, GetNext-style methods. I'm mentioning this because of the suggestions to either sort the list or to subclass it both of which is unfortunately not practical in these cases unless I copy the elements into a list of my own and I don't think that would be very efficient. I also might not have made it clear enough that the elements in the two lists are of different types, i.e. not assignment-compatible: Especially, the elements in the master list might be available as interface references only.

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• pthread and recursively calling execvp in C

  - by eduke

  To begin I'm sorry for my english :) I looking for a way to create a thread each time my program finds a directory, in order to call the program itself but with a new argv[2] argument (which is the current dir). I did it successfully with fork() but with pthread I've some difficulties. I don't know if I can do something like that : #include <unistd.h> #include <stdlib.h> #include <stdio.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/wait.h> #include <dirent.h> int main(int argc, char **argv) { pthread_t threadID[10] = {0}; DIR * dir; struct dirent * entry; struct stat status; pthread_attr_t attr; pthread_attr_init(&attr); int i = 0; char *res; char *tmp; char *file; if(argc != 3) { printf("Usage : %s <file> <dir>\n", argv[0]); exit(EXIT_FAILURE); } if(stat(argv[2],&status) == 0) { dir = opendir(argv[2]); file = argv[1]; } else exit(EXIT_FAILURE); while ((entry = readdir(dir))) { if (strcmp(entry->d_name, ".") && strcmp(entry->d_name, "..")) { tmp = malloc(strlen(argv[2]) + strlen(entry->d_name) + 2); strcpy(tmp, argv[2]); strcat(tmp, "/"); strcat(tmp, entry->d_name); stat(tmp, &status); if (S_ISDIR(status.st_mode)) { argv[2] = tmp; pthread_create( &threadID[i], &attr, execvp(argv[0], argv), NULL); printf("New thread created : %d", i); i++; } else if (!strcmp(entry->d_name, file)) { printf(" %s was found - Thread number = %d\n",tmp, i); break; } free(tmp); } } pthread_join( threadID[i] , &res ); exit(EXIT_SUCCESS); } Actually it doesn't works : pthread_create( &threadID[i], &attr, execvp(argv[0], argv), NULL); I have no runtime error, but when the file to find is in another directory, the thread is not created and so execvp(argv[0], argv) is not called... Thank you for you help, Simon

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• Another serialization ? - c#

  - by ltech

  I had asked this Yesterday If my xsd schema changes to <xs:element name="Document" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="MetaDoc" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="ATTRIBUTES" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="author" type="xs:string" minOccurs="0" /> <xs:element name="max_versions" type="xs:string" minOccurs="0" /> <xs:element name="summary" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> My xsd - class generation becomes /// <remarks/> [System.Xml.Serialization.XmlArrayAttribute(Form=System.Xml.Schema.XmlSchemaForm.Unqualified)] [System.Xml.Serialization.XmlArrayItemAttribute("MetaDoc", typeof(DocumentMetaDocATTRIBUTES[]), Form=System.Xml.Schema.XmlSchemaForm.Unqualified, IsNullable=false)] [System.Xml.Serialization.XmlArrayItemAttribute("ATTRIBUTES", typeof(DocumentMetaDocATTRIBUTES), Form=System.Xml.Schema.XmlSchemaForm.Unqualified, IsNullable=false, NestingLevel=1)] public DocumentMetaDocATTRIBUTES[][][] Document { get { return this.documentField; } set { this.documentField = value; } } If I am deriving to CollectionBase, as shown in my previous post, how would I manage the XmlArrayItemAttribute ? so that I can read this part of my input xml into my strongly types object <Document> <MetaDoc> <ATTRIBUTES> <author>asas</author> <max_versions>1</max_versions> <summary>aasasqqqq</summary> </ATTRIBUTES> </MetaDoc> </Document>

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• NSLinguisticTagger on the contents of an NSTextStorage- crashing bug

  - by Remy Porter

  I'm trying to use an NSLinguisticTagger to monitor the contents of an NSTextStorage and provide some contextual information based on what the user types. To that end, I have an OverlayManager object, which wires up this relationship: -(void) setView:(NSTextView*) view { _view = view; _layout = view.layoutManager; _storage = view.layoutManager.textStorage; //get the TextStorage from the view [_tagger setString:_storage.string]; //pull the string out, this grabs the mutable version [self registerForNotificationsOn:self->_storage]; //subscribe to the willProcessEditing notification } When an edit occurs, I make sure to trap it and notify the tagger (and yes, I know I'm being annoyingly inconsistent with member access, I'm rusty on Obj-C, I'll fix it later): - (void) textStorageWillProcessEditing:(NSNotification*) notification{ if ([self->_storage editedMask] & NSTextStorageEditedCharacters) { NSRange editedRange = [self->_storage editedRange]; NSUInteger delta = [self->_storage changeInLength]; [_tagger stringEditedInRange:editedRange changeInLength:delta]; //should notify the tagger of the changes [self highlightEdits:self]; } } The highlightEdits message delegates the job out to a pool of "Overlay" objects. Each contains a block of code similar to this: [tagger enumerateTagsInRange:range scheme:NSLinguisticTagSchemeLexicalClass options:0 usingBlock:^(NSString *tag, NSRange tokenRange, NSRange sentenceRange, BOOL *stop) { if (tag == PartOfSpeech) { [self applyHighlightToRange:tokenRange onStorage:storage]; } }]; And that's where the problem is- the enumerateTagsInRange method crashes out with a message: 2014-06-04 10:07:19.692 WritersEditor[40191:303] NSMutableRLEArray replaceObjectsInRange:withObject:length:: Out of bounds This problem doesn't occur if I don't link to the mutable copy of the underlying string and instead do a [[_storage string] copy], but obviously I don't want to copy the entire backing store every time I want to do tagging. This all should be happening in the main run loop, so I don't think this is a threading issue. The NSRange I'm enumerating tags on exists both in the NSTextStorage and in the NSLinguisticTagger's view of the string. It's not even the fact that the applyHighlightToRange call adds attributes to the string, because it crashes before even reaching that line. I attempted to build a test case around the problem, but can't replicate it in those situations: - (void) testEdit { NSAttributedString* str = [[NSMutableAttributedString alloc] initWithString:@"Quickly, this is a test."]; text = [[NSTextStorage alloc] initWithAttributedString:str]; NSArray* schemes = [NSLinguisticTagger availableTagSchemesForLanguage:@"en"]; tagger = [[NSLinguisticTagger alloc] initWithTagSchemes:schemes options:0]; [tagger setString:[text string]]; [text beginEditing]; [[text mutableString] appendString:@"T"]; NSRange edited = [text editedRange]; NSUInteger length = [text changeInLength]; [text endEditing]; [tagger stringEditedInRange:edited changeInLength:length]; [tagger enumerateTagsInRange:edited scheme:NSLinguisticTagSchemeLexicalClass options:0 usingBlock:^(NSString *tag, NSRange tokenRange, NSRange sentenceRange, BOOL *stop) { //doesn't matter, this should crash }]; } That code doesn't crash.

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• Design Technique: How to design a complex system for processing orders, products and units.

  - by Shyam

  Hi, Programming is fun: I learned that by trying out simple challenges, reading up some books and following some tutorials. I am able to grasp the concepts of writing with OO (I do so in Ruby), and write a bit of code myself. What bugs me though is that I feel re-inventing the wheel: I haven't followed an education or found a book (a free one that is) that explains me the why's instead of the how's, and I've learned from the A-team that it is the plan that makes it come together. So, armed with my nuby Ruby skills, I decided I wanted to program a virtual store. I figured out the following: My virtual Store will have: Products and Services Inventories Orders and Shipping Customers Now this isn't complex at all. With the help of some cool tools (CMapTools), I drew out some concepts, but quickly enough (thanks to my inferior experience in designing), my design started to bite me. My very first product-line were virtual "laptops". So, I created a class (Ruby): class Product attr_accessor :name, :price def initialize(name, price) @name = name @price = price end end which can be instantiated by doing (IRb) x = Product.new("Banana Pro", 250) Since I want my virtual customers to be able to purchase more than one product, or various types, I figured out I needed some kind of "Order" mechanism. class Order def initialize(order_no) @order_no = order_no @line_items = [] end def add_product(myproduct) @line_items << myproduct end def show_order() puts @order_no @line_items.each do |x| puts x.name.to_s + "\t" + x.price.to_s end end end that can be instantiated by doing (IRb) z = Order.new(1234) z.add_product(x) z.show_order Splendid, I have now a very simple ordering system that allows me to add products to an order. But, here comes my real question. What if I have three models of my product (economy, business, showoff)? Or have my products be composed out of separate units (bigger screen, nicer keyboard, different OS)? Surely I could make them three separate products, or add complexity to my product class, but I am looking for are best practices to design a flexible product object that can be used in the real world, to facilitate a complex system. My apologies if my grammar and my spelling are with error, as english is not my first language and I took the time to check as far I could understand and translate properly! Thank you for your answers, comments and feedback!

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• GAE Datastore: persisting referenced objects

  - by David

  Two "I'm sorries" to begin with: 1) I've looked for a solution (here, and elsewhere), and couldn't find the answer. 2) English is not my mother tongue, so I may have some typos and the sort - please ignore them. To the point: I am trying to persist Java objects to the GAE datastore. I am not sure as to how to persist object having ("non-trivial") referenced object. That is, assume I have the following. public class Father { String name; int age; Vector<Child> offsprings; //this is what I call "non-trivial" reference //ctor, getters, setters... } public class Child { String name; int age; Father father; //this is what I call "non-trivial" reference //ctor, getters, setters... } The name field is unique in each type domain, and is considered a Primary-Key. In order to persist the "trivial" (String, int) fields, all I need is to add the correct annotation. So far so good. However, I don't understand how should I persist the home-brewed (Child, Father) types referenced. Should I: Convert each such reference to hold the Primary-Key (a name String, in this example) instead of the "actual" object. So, Vector<Child> offsprings; becomes Vector<String> offspringsNames; ? If that is the case, how do I handle the object at run-time? Do I just query for the Primary-Key from Class.getName, to retrieve the refrenced objects? Convert each such reference to hold the actual Key provided to me by the Datastore upon the proper put() operation? So, Vector<Child> offsprings; becomes Vector<Key> offspringsHashKeys; ? I would very much appreciate all kinds of comments. I have read ALL the offical relevant GAE docs/example. Throughout, they always persist "trivial" references, natively supported by the Datastore (e.g. in the Guestbook example, only Strings, and Longs). Many thanks, David

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• jcuda library usage problem

  - by user513164

  hi m very new to java and Linux i have a code which is taken from examples of jcuda.the code is following import jcuda.CUDA; import jcuda.driver.CUdevprop; import jcuda.driver.types.CUdevice; public class EnumDevices { public static void main(String args[]) { //Init CUDA Driver CUDA cuda = new CUDA(true); int count = cuda.getDeviceCount(); System.out.println("Total number of devices: " + count); for (int i = 0; i < count; i++) { CUdevice dev = cuda.getDevice(i); String name = cuda.getDeviceName(dev); System.out.println("Name: " + name); int version[] = cuda.getDeviceComputeCapability(dev); System.out.println("Version: " + String.format("%d.%d", version[0], version[1])); CUdevprop prop = cuda.getDeviceProperties(dev); System.out.println("Clock rate: " + prop.clockRate + " MHz"); System.out.println("Threads per block: " + prop.maxThreadsPerBlock); } } } I'm using Ubuntu as my operating system i compiled it with following command 1:-javac -cp /home/manish.yadav/Desktop/JCuda-All-0.3.2-bin-linux-x86_64 EnumDevices i got following error error: Class names, 'EnumDevices', are only accepted if annotation processing is explicitly requested 1 error i don't know what is the meaning of this error.what should i do to compile the program than i changed the compiling option which is javac -cp /home/manish.yadav/Desktop/JCuda-All-0.3.2-bin-linux-x86_64 EnumDevices.java than i got following error EnumDevices.java:36: clockRate is not public in jcuda.driver.CUdevprop; cannot be accessed from outside package System.out.println("Clock rate: " + prop.clockRate + " MHz"); ^ EnumDevices.java:37: maxThreadsPerBlock is not public in jcuda.driver.CUdevprop; cannot be accessed from outside package System.out.println("Threads per block: " + prop.maxThreadsPerBlock); ^ 2 errors Now I'm completely confused i don't know what to do? how to compile this program ? how to install the jcuda package or how to use it ? how to use package which have only jar files and .so files and the jar files don't having manifest file ? please help me

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• xsl:variable contains nodeset. How to output nth node of variable?

  - by dnagirl

  I am transforming an XML document. There is an attribute @prettydate that is a string similar to "Friday, May 7, 2010". I want to split that string and add links to the month and the year. I am using the exslt:strings module and I can add any other necessary EXSLT module. This is my code so far: <xsl:template match="//calendar"> <xsl:variable name="prettyparts"> <xsl:value-of select="str:split(@prettydate,', ')"/> </xsl:variable> <table class='day'> <thead> <caption><xsl:value-of select="$prettyparts[1]"/>, <a> <xsl:attribute name='href'><xsl:value-of select="$baseref"/>?date=<xsl:value-of select="@highlight"/>&amp;per=m</xsl:attribute> <xsl:value-of select='$prettyparts[2]'/> </a> <xsl:value-of select='$prettyparts[3]'/>, <a> <xsl:attribute name='href'><xsl:value-of select="$baseref"/>?date=<xsl:value-of select="@highlight"/>&amp;per=y</xsl:attribute> <xsl:value-of select='$prettyparts[4]'/> </a> </caption> <!--etcetera--> I have verified, by running $prettyparts through a <xml:for-each/> that I am getting the expected nodeset: <token>Friday</token> <token>May</token> <token>7</token> <token>2010</token> But no matter which way I attempt to refer to a particular <token> directly (not in a foreach) I get nothing or various errors to do with invalid types. Here's some of the syntax I've tried: <xsl:value-of select="$prettyparts[2]"/> <xsl:value-of select="$prettyparts/token[2]"/> <xsl:value-of select="exsl:node-set($prettyparts/token[2])"/> <xsl:value-of select="exsl:node-set($prettyparts/token)[2]"/> Any idea what the expression ought to be?

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• Looking for Fiddler2 help. connection to gateway refused? Just got rid of a virus

  - by John Mackey

  I use Fiddler2 for facebook game items, and it's been a great success. I accessed a website to download some dat files I needed. I think it was eshare, ziddu or megaupload, one of those. Anyway, even before the rar file had downloaded, I got this weird green shield in the bottom right hand corner of my computer. It said a Trojan was trying to access my computer, or something to that extent. It prompted me to click the shield to begin anti-virus scanning. It turns out this rogue program is called Antivirus System Pro and is pretty hard to get rid of. After discovering the rogue program, I tried using Fiddler and got the following error: [Fiddler] Connection to Gateway failed.Exception Text: No connection could be made because the target machine actively refused it 127.0.0.1:5555 I ended up purchasing SpyDoctor + Antivirus, which I'm told is designed specifically for getting rid of these types of programs. Anyway, I did a quick-scan last night with spydoctor and malware bytes. Malware picked up 2 files, and Spydoctor found 4. Most were insignificant, but it did find a worm called Worm.Alcra.F, which was labeled high-priority. I don’t know if that’s the Anti-Virus Pro or not, but SpyDoctor said it got rid of all of those successfully. I tried to run Fiddler again before leaving home, but was still getting the "gateway failed" error. Im using the newest version of firefox. When I initially set up the Fiddler 2.2.8.6, I couldn’t get it to run at first, so I found this faq on the internet that said I needed to go through ToolsOptionsSettings and set up an HTTP Proxy to 127.0.0.1 and my Port to 8888. Once I set that up and downloaded this fiddler helper as a firefox add-on, it worked fine. When I turn on fiddler, it automatically takes my proxy setting from no proxy (default) to the 127.0.0.1 with Port 8888 set up. It worked fine until my computer detected this virus. Anyway, hopefully I've given you sufficient information to offer me your best advice here. Like I said, Spydoctor says the bad stuff is gone, so maybe the rogue program made some type of change in my fiddler that I could just reset or uncheck or something like that? Or will I need to completely remove fiddler and those dat files and rar files I downloaded? Any help would be greatly appreciated. Thanks for your time.

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• VB6 ADO Command to SQL Server

  - by Emtucifor

  I'm getting an inexplicable error with an ADO command in VB6 run against a SQL Server 2005 database. Here's some code to demonstrate the problem: Sub ADOCommand() Dim Conn As ADODB.Connection Dim Rs As ADODB.Recordset Dim Cmd As ADODB.Command Dim ErrorAlertID As Long Dim ErrorTime As Date Set Conn = New ADODB.Connection Conn.ConnectionString = "Provider=SQLOLEDB.1;Integrated Security=SSPI;Initial Catalog=database;Data Source=server" Conn.CursorLocation = adUseClient Conn.Open Set Rs = New ADODB.Recordset Rs.CursorType = adOpenStatic Rs.LockType = adLockReadOnly Set Cmd = New ADODB.Command With Cmd .Prepared = False .CommandText = "ErrorAlertCollect" .CommandType = adCmdStoredProc .NamedParameters = True .Parameters.Append .CreateParameter("@ErrorAlertID", adInteger, adParamOutput) .Parameters.Append .CreateParameter("@CreateTime", adDate, adParamOutput) Set .ActiveConnection = Conn Rs.Open Cmd ErrorAlertID = .Parameters("@ErrorAlertID").Value ErrorTime = .Parameters("@CreateTime").Value End With Debug.Print Rs.State ' Shows 0 - Closed Debug.Print Rs.RecordCount ' Of course this fails since the recordset is closed End Sub So this code was working not too long ago but now it's failing on the last line with the error: Run-time error '3704': Operation is not allowed when the object is closed Why is it closed? I just opened it and the SP returns rows. I ran a trace and this is what the ADO library is actually submitting to the server: declare @p1 int set @p1=1 declare @p2 datetime set @p2=''2010-04-22 15:31:07:770'' exec ErrorAlertCollect @ErrorAlertID=@p1 output,@CreateTime=@p2 output select @p1, @p2 Running this as a separate batch from my query editor yields: Msg 102, Level 15, State 1, Line 4 Incorrect syntax near '2010'. Of course there's an error. Look at the double single quotes in there. What the heck could be causing that? I tried using adDBDate and adDBTime as data types for the date parameter, and they give the same results. When I make the parameters adParamInputOutput, then I get this: declare @p1 int set @p1=default declare @p2 datetime set @p2=default exec ErrorAlertCollect @ErrorAlertID=@p1 output,@CreateTime=@p2 output select @p1, @p2 Running that as a separate batch yields: Msg 156, Level 15, State 1, Line 2 Incorrect syntax near the keyword 'default'. Msg 156, Level 15, State 1, Line 4 Incorrect syntax near the keyword 'default'. What the heck? SQL Server doesn't support this kind of syntax. You can only use the DEFAULT keyword in the actual SP execution statement. I should note that removing the extra single quotes from the above statement makes the SP run fine. ... Oh my. I just figured it out. I guess it's worth posting anyway.

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• Should I add try/catch around when casting on an attribute of JSP implicit object?

  - by Michael Mao

  Hi all: Basically what I mean is like this: List<String[]> routes = (List<String[]>)application.getAttribute("routes"); For the above code, it tries to get an attribute named "routes" from the JSP implicit object - application. But as everyone knows, after this line of code, routes may very well contains a null - which means this application hasn't got an attribute named "routes". Is this "casting on null" good programming practice in Java or not? Basically I try to avoid exceptions such as java.io.InvalidCastException I reckon things like this are more as "heritage" of Java 1.4 when generic types were not introduced to this language. So I guess everything stored in application attributes as Objects (Similar to traditional ArrayList). And when you do "downcast", there might be invalid casts. What would you do in this case? Update: Just found that although in the implicit object application I did store a List of String arrays, when I do this : List<double[]> routes = (List<double[]>)application.getAttribute("routes"); It doesn't produce any error... And I felt not comfortable already... And even with this code: out.print(routes.get(0)); It does print out something strange : [Ljava.lang.String;@18b352f Am I printing a "pointer to String"? I can finally get an exception like this: out.print(routes.get(0)[1]); with error : java.lang.ClassCastException: [Ljava.lang.String; Because it was me to add the application attribute, I know which type should it be cast to. I feel this is not "good enough", what if I forget the exact type? I know there are still some cases where this sort of thing would happen, such as in JSP/Servlet when you do casting on session attributes. Is there a better way to do this? Before you say:"OMG, why you don't use Servlets???", I should justify my reason as this: - because my uni sucks, its server can only work with Servlets generated by JSP, and I don't really want to learn how to fix issues like that. look at my previous question on this , and this is uni homework, so I've got no other choice, forget all about war, WEB-INF,etc, but "code everything directly into JSP" - because the professors do that too. :)

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• Help me understand this C code

  - by Benjamin

  INT GetTree (HWND hWnd, HTREEITEM hItem, HKEY *pRoot, TCHAR *pszKey, INT nMax) { TV_ITEM tvi; TCHAR szName[256]; HTREEITEM hParent; HWND hwndTV = GetDlgItem (hWnd, ID_TREEV); memset (&tvi, 0, sizeof (tvi)); hParent = TreeView_GetParent (hwndTV, hItem); if (hParent) { // Get the parent of the parent of the... GetTree (hWnd, hParent, pRoot, pszKey, nMax); // Get the name of the item. tvi.mask = TVIF_TEXT; tvi.hItem = hItem; tvi.pszText = szName; tvi.cchTextMax = dim(szName); TreeView_GetItem (hwndTV, &tvi); //send the TVM_GETITEM message? lstrcat (pszKey, TEXT ("\\")); lstrcat (pszKey, szName); } else { *pszKey = TEXT ('\0'); szName[0] = TEXT ('\0'); // Get the name of the item. tvi.mask = TVIF_TEXT | TVIF_PARAM; tvi.hItem = hItem; tvi.pszText = szName; tvi.cchTextMax = dim(szName); if (TreeView_GetItem (hwndTV, &tvi)) //*pRoot = (HTREEITEM)tvi.lParam; //original hItem = (HTREEITEM)tvi.lParam; else { INT rc = GetLastError(); } } return 0; } The block of code that begins with the comment "Get the name of the item" does not make sense to me. If you are getting the listview item why does the code set the parameters of the item being retrieved? If you already had the values there would be no need to retrieve them. Secondly near the comment "original" is the original line of code which will compile with a warning under embedded visual c++ 4.0, but if you copy the exact same code into visual studio 2008 it will not compile. Since I did not write any of this code, and am trying to learn, is it possible the original author made a mistake on this line? The *pRoot should point to HKEY type yet he is casting to an HTREEITEM type which should never work since the data types don't match?

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• Java - strange problem storing text to a String[] and then storing the array to a Vector. Help plea

  - by hatboysam

  OK so for background I've only been using Java for a little more than a week and I am making a basic GUI "Recipe Book" application just to test out some of the techniques I've learned. Currently I'm working on the "Add New Recipe" page that allows the user to make a new recipe by adding ingredients one at a time. The ingredients have 3 attributes: Name, amount, and unit (like cups, oz, etc) that come from two text fields and a combo box respectively. The 3 values are stores as strings to a String array that represents the ingredient, then the arrays are stored in a vector that holds all of the ingredients for one recipe. When an ingredient is added, the user first types in the 3 necessary values into empty boxes/combo box dropdown and then clicks "Add Ingredient". Here is my code for when the button is clicked: public void actionPerformed(ActionEvent event) { Object source = event.getSource(); if (source == addIngredientButton) { //make sure 3 ingredient fields are not blank if (!ingredientNameField.getText().equals("") && !ingredientAmountField.getText().equals("") && !ingredientUnitDropdown.getSelectedItem().equals("")) { tempIngredientsArray[0] = ingredientNameField.getText(); //set ingredient name to first position in array tempIngredientsArray[1] = ingredientAmountField.getText(); //set ingredient amount to second position in array tempIngredientsArray[2] = (String) ingredientUnitDropdown.getSelectedItem(); //set ingredient unit to third position in array int ingredientsVectorSize = tempRecipe.ingredientsVector.size(); tempRecipe.ingredientsVector.add(this.tempIngredientsArray); //why would it matter if this and previous statement were switched for (int k = 0; k < ingredientsVectorSize + 1; k++ ) { liveIngredientsListArea.append("\n" + tempRecipe.makeIngredientSentence(k)); System.out.println(Arrays.toString(tempIngredientsArray)); //shows that tempIngredientsArray gets messed up each time } } Now here's the really strange problem I've been having. The first time the user adds an ingredient everything works fine. The second time, the String[] for that ingredient seems to be duplicated, and the third time it's triplicated. Aka the first time it runs the System.out.println might return "{Sugar, 3, Cups}" and the second time it will return "{Flour, 2, Oz.} {Flour, 2, Oz.}" etc. What's causing this strange problem? All help greatly appreciated, let me know if you need any clarification.

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