Search Results

Search found 4999 results on 200 pages for 'derived instances'.

Page 34/200 | < Previous Page | 30 31 32 33 34 35 36 37 38 39 40 41  | Next Page >

• Performance of C# method polymorphism with generics

  - by zildjohn01

  I noticed in C#, unlike C++, you can combine virtual and generic methods. For example: using System.Diagnostics; class Base { public virtual void Concrete() {Debug.WriteLine("base concrete");} public virtual void Generic<T>() {Debug.WriteLine("base generic");} } class Derived : Base { public override void Concrete() {Debug.WriteLine("derived concrete");} public override void Generic<T>() {Debug.WriteLine("derived generic");} } class App { static void Main() { Base x = new Derived(); x.Concrete(); x.Generic<PerformanceCounter>(); } } Given that any number of versions of Generic<T> could be instantiated, it doesn't look like the standard vtbl approach could be used to resolve method calls, and in fact it's not. Here's the generated code: x.Concrete(); mov ecx,dword ptr [ebp-8] mov eax,dword ptr [ecx] call dword ptr [eax+38h] x.Generic<PerformanceCounter>(); push 989A38h mov ecx,dword ptr [ebp-8] mov edx,989914h call 76A874F1 mov dword ptr [ebp-4],eax mov ecx,dword ptr [ebp-8] call dword ptr [ebp-4] The extra code appears to be looking up a dynamic vtbl according to the generic parameters, and then calling into it. Has anyone written about the specifics of this implementation? How well does it perform compared to the non-generic case?

  Read the article

• c++ Design pattern for CoW, inherited classes, and variable shared data?

  - by krunk

  I've designed a copy-on-write base class. The class holds the default set of data needed by all children in a shared data model/CoW model. The derived classes also have data that only pertains to them, but should be CoW between other instances of that derived class. I'm looking for a clean way to implement this. If I had a base class FooInterface with shared data FooDataPrivate and a derived object FooDerived. I could create a FooDerivedDataPrivate. The underlying data structure would not effect the exposed getters/setters API, so it's not about how a user interfaces with the objects. I'm just wondering if this is a typical MO for such cases or if there's a better/cleaner way? What peeks my interest, is I see the potential of inheritance between the the private data classes. E.g. FooDerivedDataPrivate : public FooDataPrivate, but I'm not seeing a way to take advantage of that polymorphism in my derived classes. class FooDataPrivate { public: Ref ref; // atomic reference counting object int a; int b; int c; }; class FooInterface { public: // constructors and such // .... // methods are implemented to be copy on write. void setA(int val); void setB(int val); void setC(int val); // copy constructors, destructors, etc. all CoW friendly private: FooDataPrivate *data; }; class FooDerived : public FooInterface { public: FooDerived() : FooInterface() {} private: // need more shared data for FooDerived // this is the ???, how is this best done cleanly? };

  Read the article

• What is wrong with locking non-static fields? What is the correct way to lock a particular instance?

  - by smartcaveman

  Why is it considered bad practice to lock non-static fields? And, if I am not locking non-static fields, then how do I lock an instance method without locking the method on all other instances of the same or derived class? I wrote an example to make my question more clear. public abstract class BaseClass { private readonly object NonStaticLockObject = new object(); private static readonly object StaticLockObject = new object(); protected void DoThreadSafeAction<T>(Action<T> action) where T: BaseClass { var derived = this as T; if(derived == null) { throw new Exception(); } lock(NonStaticLockObject) { action(derived); } } } public class DerivedClass :BaseClass { private readonly Queue<object> _queue; public void Enqueue(object obj) { DoThreadSafeAction<DerivedClass>(x=>x._queue.Enqueue(obj)); } } If I make the lock on the StaticLockObject, then the DoThreadSafeAction method will be locked for all instances of all classes that derive from BaseClass and that is not what I want. I want to make sure that no other threads can call a method on a particular instance of an object while it is locked.

  Read the article

• Compile time type determination in C++

  - by dicroce

  A coworker recently showed me some code that he found online. It appears to allow compile time determination of whether a type has an "is a" relationship with another type. I think this is totally awesome, but I have to admit that I'm clueless as to how this actually works. Can anyone explain this to me? template<typename BaseT, typename DerivedT> inline bool isRelated(const DerivedT&) { DerivedT derived(); char test(const BaseT&); // sizeof(test()) == sizeof(char) char (&test(...))[2]; // sizeof(test()) == sizeof(char[2]) struct conversion { enum { exists = (sizeof(test(derived())) == sizeof(char)) }; }; return conversion::exists; } Once this function is defined, you can use it like this: #include <iostream> class base {}; class derived : public base {}; class unrelated {}; int main() { base b; derived d; unrelated u; if( isRelated<base>( b ) ) std::cout << "b is related to base" << std::endl; if( isRelated<base>( d ) ) std::cout << "d is related to base" << std::endl; if( !isRelated<base>( u ) ) std::cout << "u is not related to base" << std::endl; }

  Read the article

• Why it's can be compiled in GNU/C++, can't compiled in VC++2010 RTM?

  - by volnet

  #include #include #include #include "copy_of_auto_ptr.h" #ifdef _MSC_VER #pragma message("#include ") #include // http://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Pragmas.html#Diagnostic-Pragmas #endif /* case 1-4 is the requirement of the auto_ptr. which form http://ptgmedia.pearsoncmg.com/images/020163371X/autoptrupdate/auto_ptr_update.html */ /* case 1. (1) Direct-initialization, same type, e.g. */ std::auto_ptr source_int() { // return std::auto_ptr(new int(3)); std::auto_ptr tmp(new int(3)); return tmp; } /* case 2. (2) Copy-initialization, same type, e.g. */ void sink_int(std::auto_ptr p) { std::cout source_derived() { // return std::auto_ptr(new Derived()); std::auto_ptr tmp(new Derived()); return tmp; } /* case 4. (4) Copy-initialization, base-from-derived, e.g. */ void sink_base( std::auto_ptr p) { p-go(); } int main(void) { /* // auto_ptr */ // case 1. // auto_ptr std::auto_ptr p_int(source_int()); std::cout p_derived(source_derived()); p_derived-go(); // case 4. // auto_ptr sink_base(source_derived()); return 0; } In Eclipse(GNU C++.exe -v gcc version 3.4.5 (mingw-vista special r3)) it's two compile error: Description Resource Path Location Type initializing argument 1 of void sink_base(std::auto_ptr<Base>)' from result ofstd::auto_ptr<_Tp::operator std::auto_ptr<_Tp1() [with _Tp1 = Base, _Tp = Derived]' auto_ptr_ref_research.cpp auto_ptr_ref_research/auto_ptr_ref_research 190 C/C++ Problem Description Resource Path Location Type no matching function for call to `std::auto_ptr::auto_ptr(std::auto_ptr)' auto_ptr_ref_research.cpp auto_ptr_ref_research/auto_ptr_ref_research 190 C/C++ Problem But it's right in VS2010 RTM. Questions: Which compiler stand for the ISO C++ standard? The content of case 4 is the problem "auto_ptr & auto_ptr_ref want to resolve?"

  Read the article

• Is this an error in "More Effective C++" in Item28?

  - by particle128

  I encountered a question when I was reading the item28 in More Effective C++ .In this item, the author shows to us that we can use member template in SmartPtr such that the SmartPtr<Cassette> can be converted to SmartPtr<MusicProduct>. The following code is not the same as in the book,but has the same effect. #include <iostream> class Base{}; class Derived:public Base{}; template<typename T> class smart{ public: smart(T* ptr):ptr(ptr){} template<typename U> operator smart<U>() { return smart<U>(ptr); } ~smart(){delete ptr;} private: T* ptr; }; void test(const smart<Base>& ) {} int main() { smart<Derived> sd(new Derived); test(sd); return 0; } It indeed can be compiled without compilation error. But when I ran the executable file, I got a core dump. I think that's because the member function of the conversion operator makes a temporary smart, which has a pointer to the same ptr in sd (its type is smart<Derived>). So the delete directive operates twice. What's more, after calling test, we can never use sd any more, since ptr in sd has already been delete. Now my questions are : Is my thought right? Or my code is not the same as the original code in the book? If my thought is right, is there any method to do this? Thanks very much for your help.

  Read the article

• Mutate an object into an instance of one its subclasses

  - by Gohu

  Hi, Is it possible to mutate an object into an instance of a derived class of the initial's object class? Something like: class Base(): def __init__(self): self.a = 1 def mutate(self): self = Derived() class Derived(Base): def __init__(self): self.b = 2 But that doesn't work. >>> obj = Base() >>> obj.mutate() >>> obj.a 1 >>> obj.b AttributeError... If this isn't possible, how should I do otherwise? My problem is the following: My Base class is like a "summary", and the Derived class is the "whole thing". Of course getting the "whole thing" is a bit expensive so working on summaries as long as it is possible is the point of having these two classes. But you should be able to get it if you want, and then there's no point in having the summary anymore, so every reference to the summary should now be (or contain, at least) the whole thing. I guess I would have to create a class that can hold both, right? class Thing(): def __init__(self): self.summary = Summary() self.whole = None def get_whole_thing(self): self.whole = Whole()

  Read the article

• BizTalk Server Monitoring &ndash; SharePoint Web Part

  - by SURESH GIRIRAJAN

  I have been worked with customers using BizTalk as shared infrastructure in the enterprise, where we have two or more BizTalk apps running on it for different Business groups. Also these customers are not using BizTalk ESB portal even though they are using BizTalk ESB exception framework. So main issue with all these Business groups are they don’t have visibility into the BizTalk apps running in prod, even though they are using SCOM and other monitoring stuff in place. So I am trying to address few issues I am going to list below and how I try to mitigate them, first one on the list is how to get visibility into prod, how to provision those access to the BizTalk resources with minimal activity and how can we take advantage of the resources we have today. So I was working on creating REST data services for BizTalk RFID a year ago and available on codeplex. I thought to extend that idea to take advantage of BizTalk Data Services available in codeplex. I extended the BizTalk data services I will upload the updated service soon. So let me start thru how my solution works, so first step I am using the BizTalk data service (REST service) which expose most of the BizTalk artifacts as resources such as Applications, Orchestrations, Send ports, Receive ports, Host instances and In process instances etc. BizTalk Server Monitoring – SharePoint Web Part I am hosting the BizTalk data service in IIS with application pool configured to run under BizTalk administrator credentials. So with this setup I am making the service to make accessible anonymous. Next step of this solution I have created a SharePoint Visual web part which consumes the BizTalk data service and display all the BizTalk Application and Platform settings in read only mode. Even though BizTalk data services offers to browse resources as well perform actions like starting, stopping Orchestrations, Send ports, Receive locations, Host instances etc. Host Instances BizTalk Applications BizTalk Running / Suspended Instances So having this BizTalk Monitoring SharePoint web part, will be added to the SharePoint. This eliminates the need for granting access to the BizTalk users explicitly, so when you have BizTalk contractor or BizTalk application user need to have access to the BizTalk environment all the need is have access to the SharePoint website. You can configure the web part point to different end point based on your environment. I am making this as read only as part of this to make easier for the users and in terms of provisioning. This removes the dependency of BizTalk admin at least for viewing the BizTalk application status and errors etc. If we need to make any changes to the BizTalk application then its application owner responsibility to co-ordinate with BizTalk admins. There are options like BizTalk ESB portal, BizTalk 360 etc… but this one of the approach to reduce number of steps required to give access to BizTalk application users and also to maximize the resource we have in enterprise today. Also you can expose this data service thru Azure Service Bus and access from other apps like mobile devices or create a web site hosted in Azure etc. One last thing I have tested only with BizTalk Server 2010 on x64 VM only, but it should work on other version. I will try to upload the code shortly with instructions how to setup etc.… I welcome thoughts and suggestions… Hope this helps….

  Read the article

• Where should instantiated classes be stored?

  - by Eric C.

  I'm having a bit of a design dilemma here. I'm writing a library that consists of a bunch of template classes that are designed to be used as a base for creating content. For example: public class Template { public string Name {get; set;} public string Description {get; set;} public string Attribute1 {get; set;} public string Attribute2 {get; set;} public Template() { //constructor } public void DoSomething() { //does something } ... } The problem is, not only is the library providing the templates, it will also supply quite a few predefined templates which are instances of these template classes. The question is, where do I put these instances of the templates? The three solutions I've come up with so far are: 1) Provide serialized instances of the templates as files. On the one hand, this solution would keep the instances separated from the library itself, which is nice, but it would also potentially add complexity for the user. Even if we provided methods for loading/deserializing the files, they'd still have to deal with a bunch of files, and some kind of config file so the app knows where to look for those files. Plus, creating the template files would probably require a separate app, so if the user wanted to stick with the files method of storing templates, we'd have to provide some kind of app for creating the template files. Also, this requires external dependencies for testing the templates in the user's code. 2) Add readonly instances to the template class Example: public class Template { public string Name {get; set;} public string Description {get; set;} public string Attribute1 {get; set;} public string Attribute2 {get; set;} public Template PredefinedTemplate { get { Template templateInstance = new Template(); templateInstance.Name = "Some Name"; templateInstance.Description = "A description"; ... return templateInstance; } } public Template() { //constructor } public void DoSomething() { //does something } ... } This method would be convenient for users, as they would be able to access the predefined templates in code directly, and would be able to unit test code that used them. The drawback here is that the predefined templates pollute the Template type namespace with a bunch of extra stuff. I suppose I could put the predefined templates in a different namespace to get around this drawback. The only other problem with this approach is that I'd have to basically duplicate all the namespaces in the library in the predefined namespace (e.g. Templates.SubTemplates and Predefined.Templates.SubTemplates) which would be a pain, and would also make refactoring more difficult. 3) Make the templates abstract classes and make the predefined templates inherit from those classes. For example: public abstract class Template { public string Name {get; set;} public string Description {get; set;} public string Attribute1 {get; set;} public string Attribute2 {get; set;} public Template() { //constructor } public void DoSomething() { //does something } ... } and public class PredefinedTemplate : Template { public PredefinedTemplate() { this.Name = "Some Name"; this.Description = "A description"; this.Attribute1 = "Some Value"; ... } } This solution is pretty similar to #2, but it ends up creating a lot of classes that don't really do anything (none of our predefined templates are currently overriding behavior), and don't have any methods, so I'm not sure how good a practice this is. Has anyone else had any experience with something like this? Is there a best practice of some kind, or a different/better approach that I haven't thought of? I'm kind of banging my head against a wall trying to figure out the best way to go. Thanks!

  Read the article

• BizTalk server problem

  - by WtFudgE

  Hi, we have a biztalk server (a virtual one (1!)...) at our company, and an sql server where the data is being kept. Now we have a lot of data traffic. I'm talking about hundred of thousands. So I'm actually not even sure if one server is pretty safe, but our company is not that easy to convince. Now recently we have a lot of problems. Allow me to situate in detail, so I'm not missing anything: Our server has 5 applications: One with 3 orchestrations, 12 send ports, 16 receive locations. One with 4 orchestrations, 32 send ports, 20 receive locations. One with 4 orchestrations, 24 send ports, 20 receive locations. One with 47 (yes 47) orchestrations, 37 send ports, 6 receive locations. One with common application with a couple of resources. Our problems have occured since we deployed the applications with the 47 orchestrations. A lot of these orchestrations use assign shapes which use c# code to do the mapping. This is because we use HL7 extensions and this is kind of special, so by using c# code & xpath it was a lot easier to do the mapping because a lot of these schema's look alike. The c# reads in XmlNodes received through xpath, and returns XmlNode which are then assigned again to biztalk messages. I'm not sure if this could be the cause, but I thought I'd mention it. The send and receive ports have a lot of different types: File, MQSeries, SQL, MLLP, FTP. Each of these types have a different host instances, to balance out the load. Our orchestrations use the BiztalkApplication host. On this server also a couple of scripts are running, mostly ftp upload scripts & also a zipper script, which zips files every half an hour in a daily zip and deletes the zip files after a month. We use this zipscript on our backup files (we backup a lot, backups are also on our server), we did this because the server had problems with sending files to a location where there were a lot (A LOT) of files, so after the files were reduced to zips it went better. Now the problems we are having recently are mainly two major problems: Our most important problem is the following. We kept a receive location with a lot of messages on a queue for testing. After we start this receive location which uses the 47 orchestrations, the running service instances start to sky rock. Ok, this is pretty normal. Let's say about 10000, and then we stop the receive location to see how biztalk handles these 10000 instances. Normally they would go down pretty fast, and it does sometimes, but after a while it starts to "throttle", meaning they just stop being processed and the service instances stay at the same number, for example in 30 seconds it goes down from 10000 to 4000 and then it stays at 4000 and it lowers very very very slowly, like 30 in 5minutes or something. So this means, that all the other service instances of the other applications are also stuck in here, and they are also not processed. We noticed that after restarting our host instances the instance number went down fast again. So we tried to selectively restart different host instances to locate the problem. We noticed that eventually restarting the file send/receive host instance would do the trick. So we thought file sends would be the problem. Concidering that we make a lot of backups. So we replaced the file type backups with mqseries backups. The same problem occured, and funny thing, restarting the file send/receive host still fixes the problem. No errors can be found in the event viewer either. A second problem we're having is. That sometimes at arround 6 am, all or a part of the host instances are being stopped. In the event viewer we noticed the following errors (these are more than one): The receive location "MdnBericht SQL" with URL "SQL://ZNACDBPEG/mdnd0001/" is shutting down. Details:"The error threshold has been exceeded. The receive location is shutting down.". The Messaging Engine failed to add a receive location "M2m Othello Export Start Bestand" with URL "\m2mservices\Othello_import$\DataFilter Start*.xml" to the adapter "FILE". Reason: "The FILE adapter cannot access the folder \m2mservices\Othello_import$\DataFilter Start. Verify this folder exists. Error: Logon failure: unknown user name or bad password. ". The FILE adapter cannot access the folder \m2mservices\Othello_import$\DataFilter Start. Verify this folder exists. Error: Logon failure: unknown user name or bad password. An attempt to connect to "BizTalkMsgBoxDb" SQL Server database on server "ZNACDBBTS" failed. Error: "Login failed for user ''. The user is not associated with a trusted SQL Server connection." It woould seem that there's a login failure at this time and that because of it other services are also experiencing problems, and eventually they are shut down. The thing is, our user is admin, and it's impossible that it's password is wrong "sometimes". We have concidering that the problem could be due to an infrastructure problem, but that's not really are department. I know it's a long post, but we're not sure anymore what to do. Would adding another server and balancing the load solve our problems? Is there a way to meassure our balance and know where to start splitting? What are normal numbers of load etc? I appreciate any answers because these issues are getting worse and we're also on a deadline. Thanks a lot for replies!

  Read the article

• Lucene complex structure search

  - by archer

  Basically I do have pretty simple database that I'd like to index with Lucene. Domains are: // Person domain class Person { Set<Pair> keys; } // Pair domain class Pair { KeyItem keyItem; String value; } // KeyItem domain, name is unique field within the DB (!!) class KeyItem{ String name; } I've tens of millions of profiles and hundreds of millions of Pairs, however, since most of KeyItem's "name" fields duplicates, there are only few dozens KeyItem instances. Came up to that structure to save on KeyItem instances. Basically any Profile with any fields could be saved into that structure. Lets say we've profile with properties - name: Andrew Morton - eduction: University of New South Wales, - country: Australia, - occupation: Linux programmer. To store it, we'll have single Profile instance, 4 KeyItem instances: name, education,country and occupation, and 4 Pair instances with values: "Andrew Morton", "University of New South Wales", "Australia" and "Linux Programmer". All other profile will reference (all or some) same instances of KeyItem: name, education, country and occupation. My question is, how to index all of that so I can search for Profile for some particular values of KeyItem::name and Pair::value. Ideally I'd like that kind of query to work: name:Andrew* AND occupation:Linux* Should I create custom Indexer and Searcher? Or I could use standard ones and just map KeyItem and Pair as Lucene components somehow?

  Read the article

• How to get the list of SqlInstances of a paricular machine

  - by Cute

  Can anyone tell me how to get remote Sqlserver instances using c# and SMO or any api? I have a remote server name "RemoteMC", which has 2 instances of sql server: "RemoteMc" and "RemoteMC\sqlexpress" I try to get the instances in code like this: Server srv=new Server("RemoteMC"); DataTable dt=SmoApplication.EnumAvailableSqlServer(true); But it returns "Host\sqlexpress" I don't know what went wrong. How can I get the result back as: RemoteMC RemoteMC\sqlexpress; ?

  Read the article

• how to aviod infinite loop in observer pattern?

  - by joseph

  Hello. I have only one class with many instances. Every instance is observer of couple of other instances. As well every instance can be observable by couple of another instances. How to avoid infinite loop of calling update() in observers?

  Read the article

• [numpy] storing record arrays in object arrays

  - by Peter Prettenhofer

  I'd like to convert a list of record arrays -- dtype is (uint32, float32) -- into a numpy array of dtype np.object: X = np.array(instances, dtype = np.object) where instances is a list of arrays with data type np.dtype([('f0', '<u4'), ('f1', '<f4')]). However, the above statement results in an array whose elements are also of type np.object: X[0] array([(67111L, 1.0), (104242L, 1.0)], dtype=object) Does anybody know why? The following statement should be equivalent to the above but gives the desired result: X = np.empty((len(instances),), dtype = np.object) X[:] = instances X[0] array([(67111L, 1.0), (104242L, 1.0), dtype=[('f0', '<u4'), ('f1', '<f4')]) thanks & best regards, peter

  Read the article

• Asp.net Mvc - Kigg: Maintain User object in HttpContext.Items between requests.

  - by Pickels

  Hallo, first I want to say that I hope this doesn't look like I am lazy but I have some trouble understanding a piece of code from the following project. http://kigg.codeplex.com/ I was going through the source code and I noticed something that would be usefull for my own little project I am making. In their BaseController they have the following code: private static readonly Type CurrentUserKey = typeof(IUser); public IUser CurrentUser { get { if (!string.IsNullOrEmpty(CurrentUserName)) { IUser user = HttpContext.Items[CurrentUserKey] as IUser; if (user == null) { user = AccountRepository.FindByClaim(CurrentUserName); if (user != null) { HttpContext.Items[CurrentUserKey] = user; } } return user; } return null; } } This isn't an exact copy of the code I adjusted it a little to my needs. This part of the code I still understand. They store their IUser in HttpContext.Items. I guess they do it so that they don't have to call the database eachtime they need the User object. The part that I don't understand is how they maintain this object in between requests. If I understand correctly the HttpContext.Items is a per request cache storage. So after some more digging I found the following code. internal static IDictionary<UnityPerWebRequestLifetimeManager, object> GetInstances(HttpContextBase httpContext) { IDictionary<UnityPerWebRequestLifetimeManager, object> instances; if (httpContext.Items.Contains(Key)) { instances = (IDictionary<UnityPerWebRequestLifetimeManager, object>) httpContext.Items[Key]; } else { lock (httpContext.Items) { if (httpContext.Items.Contains(Key)) { instances = (IDictionary<UnityPerWebRequestLifetimeManager, object>) httpContext.Items[Key]; } else { instances = new Dictionary<UnityPerWebRequestLifetimeManager, object>(); httpContext.Items.Add(Key, instances); } } } return instances; } This is the part where some magic happens that I don't understand. I think they use Unity to do some dependency injection on each request? In my project I am using Ninject and I am wondering how I can get the same result. I guess InRequestScope in Ninject is the same as UnityPerWebRequestLifetimeManager? I am also wondering which class/method they are binding to which interface? Since the HttpContext.Items get destroyed each request how do they prevent losing their user object? Anyway it's kinda a long question so I am gradefull for any push in the right direction. Kind regards, Pickels

  Read the article

• Simple "Hello World!" console application crashes when run by windows TaskScheduler (1.0)

  - by user326627

  I have a batch file which starts multiple instances of simple console application (Hello World!). I work on Windows server 2008 64-bit. I configure it to run in TaskScheduler, at startup, and whether user is logged-in or not. The later configuration means that the instances will run without GUI (i.e. - no window). When I run this task, some of the instances just fail, after consuming 100& CPU. Application event-log shows the following error: "Faulting module KERNEL32.dll, version 6.0.6002.18005, time stamp 0x49e0421d, exception code 0xc0000142, fault offset 0x00000000000b8fb8, process id 0x29bc, application start time 0x01cae17d94a61895." Running the batch file directly works just fine. It seems to me that the OS has a problem loading too many instances of the application when no window is displayed. However - I can’t figure out why... Any idea??

  Read the article

• a linq query to find something

  - by rap-uvic

  Hi, I have object A which contains multiple instances of object B, which in turn contains multiple instances of object C. I need to write a function which, given Object A needs search through instances of objects B and objects C and find a particular object C. How would I do this using LINQ?

  Read the article

• What happens when I instantiate class in Python?

  - by Konstantin

  Could you clarify some ideas behind Python classes and class instances? Consider this: class A(): name = 'A' a = A() a.name = 'B' # point 1 (instance of class A is used here) print a.name print A.name prints: B A if instead in point 1 I use class name, output is different: A.name = 'B' # point 1 (updated, class A itself is used here) prints: B B Even if classes in Python were some kind of prototype for class instances, I'd expect already created instances to remain intact, i.e. output like this: A B Can you explain what is actually going on?

  Read the article

• C#/XNA Giant Memory Leak

  - by user1440926

  this is my first post here. I'm making a game in Visual Studio 2010 using XNA, and i've hit a giant memory leak. My game starts out using 17k ram and then after ten minutes it's upto 65k. I ran some memory profilers, and they all say that new instances of the String object are being created, but they aren't live. The amount of live instances of String hasn't changed at all. It's also creating instances of Char[] (which i'd expect from it), Object[], and StringBuilder. My game is pretty new but there's too much code to post here. I have no idea how to get rid of instances that aren't live, please help!

  Read the article

• Is an Object the smallest pageable unit in the Heap?

  - by DonnieKun

  Hi, If I have a 2 GB ram and I have an 2 instances of an Object which is 1.5 GB each, the operating system will help and context switch the pages to and from harddisk. What if I have 1 instances but is 3 GB. Can the same paging method breakdown this instances into 2 pages? Or will I encounter out-of-memory issue? Thanks.

  Read the article

• Communication Between Your PC and Azure VM via Windows Azure Connect

  - by Shaun

  With the new release of the Windows Azure platform there are a lot of new features available. In my previous post I introduced a little bit about one of them, the remote desktop access to azure virtual machine. Now I would like to talk about another cool stuff – Windows Azure Connect.   What’s Windows Azure Connect I would like to quote the definition of the Windows Azure Connect in MSDN With Windows Azure Connect, you can use a simple user interface to configure IP-sec protected connections between computers or virtual machines (VMs) in your organization’s network, and roles running in Windows Azure. IP-sec protects communications over Internet Protocol (IP) networks through the use of cryptographic security services. There’s an image available at the MSDN as well that I would like to forward here As we can see, using the Windows Azure Connect the Worker Role 1 and Web Role 1 are connected with the development machines and database servers which some of them are inside the organization some are not. With the Windows Azure Connect, the roles deployed on the cloud could consume the resource which located inside our Intranet or anywhere in the world. That means the roles can connect to the local database, access the local shared resource such as share files, folders and printers, etc.   Difference between Windows Azure Connect and AppFabric It seems that the Windows Azure Connect are duplicated with the Windows Azure AppFabric. Both of them are aiming to solve the problem on how to communication between the resource in the cloud and inside the local network. The table below lists the differences in my understanding. Category Windows Azure Connect Windows Azure AppFabric Purpose An IP-sec connection between the local machines and azure roles. An application service running on the cloud. Connectivity IP-sec, Domain-joint Net Tcp, Http, Https Components Windows Azure Connect Driver Service Bus, Access Control, Caching Usage Azure roles connect to local database server Azure roles use local shared files,  folders and printers, etc. Azure roles join the local AD. Expose the local service to Internet. Move the authorization process to the cloud. Integrate with existing identities such as Live ID, Google ID, etc. with existing local services. Utilize the distributed cache.   And also some scenarios on which of them should be used. Scenario Connect AppFabric I have a service deployed in the Intranet and I want the people can use it from the Internet.   Y I have a website deployed on Azure and need to use a database which deployed inside the company. And I don’t want to expose the database to the Internet. Y   I have a service deployed in the Intranet and is using AD authorization. I have a website deployed on Azure which needs to use this service. Y   I have a service deployed in the Intranet and some people on the Internet can use it but need to be authorized and authenticated.   Y I have a service in Intranet, and a website deployed on Azure. This service can be used from Internet and that website should be able to use it as well by AD authorization for more functionalities. Y Y   How to Enable Windows Azure Connect OK we talked a lot information about the Windows Azure Connect and differences with the Windows Azure AppFabric. Now let’s see how to enable and use the Windows Azure Connect. First of all, since this feature is in CTP stage we should apply before use it. On the Windows Azure Portal we can see our CTP features status under Home, Beta Program page. You can send the apply to join the Beta Programs to Microsoft in this page. After a few days the Microsoft will send an email to you (the email of your Live ID) when it’s available. In my case we can see that the Windows Azure Connect had been activated by Microsoft and then we can click the Connect button on top, or we can click the Virtual Network item from the left navigation bar.   The first thing we need, if it’s our first time to enter the Connect page, is to enable the Windows Azure Connect. After that we can see our Windows Azure Connect information in this page.   Add a Local Machine to Azure Connect As we explained below the Windows Azure Connect can make an IP-sec connection between the local machines and azure role instances. So that we firstly add a local machine into our Azure Connect. To do this we will click the Install Local Endpoint button on top and then the portal will give us an URL. Copy this URL to the machine we want to add and it will download the software to us. This software will be installed in the local machines which we want to join the Connect. After installed there will be a tray-icon appeared to indicate this machine had been joint our Connect. The local application will be refreshed to the Windows Azure Platform every 5 minutes but we can click the Refresh button to let it retrieve the latest status at once. Currently my local machine is ready for connect and we can see my machine in the Windows Azure Portal if we switched back to the portal and selected back Activated Endpoints node.   Add a Windows Azure Role to Azure Connect Let’s create a very simple azure project with a basic ASP.NET web role inside. To make it available on Windows Azure Connect we will open the azure project property of this role from the solution explorer in the Visual Studio, and select the Virtual Network tab, check the Activate Windows Azure Connect. The next step is to get the activation token from the Windows Azure Portal. In the same page there is a button named Get Activation Token. Click this button then the portal will display the token to me. We copied this token and pasted to the box in the Visual Studio tab. Then we deployed this application to azure. After completed the deployment we can see the role instance was listed in the Windows Azure Portal - Virtual Connect section.   Establish the Connect Group The final task is to create a connect group which contains the machines and role instances need to be connected each other. This can be done in the portal very easy. The machines and instances will NOT be connected until we created the group for them. The machines and instances can be used in one or more groups. In the Virtual Connect section click the Groups and Roles node from the left side navigation bar and clicked the Create Group button on top. This will bring up a dialog to us. What we need to do is to specify a group name, description; and then we need to select the local computers and azure role instances into this group. After the Azure Fabric updated the group setting we can see the groups and the endpoints in the page. And if we switch back to the local machine we can see that the tray-icon have been changed and the status turned connected. The Windows Azure Connect will update the group information every 5 minutes. If you find the status was still in Disconnected please right-click the tray-icon and select the Refresh menu to retrieve the latest group policy to make it connected.   Test the Azure Connect between the Local Machine and the Azure Role Instance Now our local machine and azure role instance had been connected. This means each of them can communication to others in IP level. For example we can open the SQL Server port so that our azure role can connect to it by using the machine name or the IP address. The Windows Azure Connect uses IPv6 to connect between the local machines and role instances. You can get the IP address from the Windows Azure Portal Virtual Network section when select an endpoint. I don’t want to take a full example for how to use the Connect but would like to have two very simple tests. The first one would be PING.   When a local machine and role instance are connected through the Windows Azure Connect we can PING any of them if we opened the ICMP protocol in the Filewall setting. To do this we need to run a command line before test. Open the command window on the local machine and the role instance, execute the command as following netsh advfirewall firewall add rule name="ICMPv6" dir=in action=allow enable=yes protocol=icmpv6 Thanks to Jason Chen, Patriek van Dorp, Anton Staykov and Steve Marx, they helped me to enable  the ICMPv6 setting. For the full discussion we made please visit here. You can use the Remote Desktop Access feature to logon the azure role instance. Please refer my previous blog post to get to know how to use the Remote Desktop Access in Windows Azure. Then we can PING the machine or the role instance by specifying its name. Below is the screen I PING my local machine from my azure instance. We can use the IPv6 address to PING each other as well. Like the image following I PING to my role instance from my local machine thought the IPv6 address.   Another example I would like to demonstrate here is folder sharing. I shared a folder in my local machine and then if we logged on the role instance we can see the folder content from the file explorer window.   Summary In this blog post I introduced about another new feature – Windows Azure Connect. With this feature our local resources and role instances (virtual machines) can be connected to each other. In this way we can make our azure application using our local stuff such as database servers, printers, etc. without expose them to Internet.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

  Read the article

• OFM 11g: Implementing OAM SSO with Forms

  - by olaf.heimburger

  There is some confusion about the integration of OFM 11g Forms with Oracle Access Manager 11g (OAM). Some say this does not work, some say it works, but.... Actually, having implemented it many times I belong to the later group. Here is how. Caveat Before you start installing anything, take a step back and consider your current implementation and what you really need and want to achieve. The current integration of Forms 11g with OAM 11g does not support self-service account creation and password resets from the Forms application. If you really need this, you must use the existing Oracle AS 10.1.4.3 infrastructure. On the other hand, if your user population is pretty stable, you can enjoy the latest Forms 11g with OAM 11g. Assumptions The whole process should be done in one day. I assume that all domains and instances are started during setup, if you need to restart them on demand or purpose, be sure to have proper start/stop scripts, I don't mention them. Preparation It goes without saying, that you always should do a proper backup before you change anything on your production environment. With proper backup, I also mean a tested and verified restore process. If you dared to test it before, do it now. It pays off. Requirements For OAM 11g to work properly you need a LDAP repository. For the integration of Forms 11g you need an Oracle Internet Directory (OID) configured with the Oracle AS SSO LDAP extensions. For better support I usually give the latest version a try, in this case OID 11g is a good choice.During the Installation and Integration steps we use an upgrade wizard that needs the old OID configuration on the same host but in a different ORACLE_HOME. Installation vs Configuration With OFM 11g Oracle introduced a clear separation between Installation of the binaries (the software) and the Configuration of the instances (the runtime). This is really great as you can install all the software and create new instances when needed. In the following we adhere to this scheme and install the software first and then configure the instances later. Installation Steps The Oracle documentation contains all the necessary steps for the installation of all pieces of software. But some hints help to avoid traps and pitfalls. Step 1 The Database Start the installation with the database. It is quite obvious but we need an Oracle database for all the other steps. If you have one at hand, fine. If not, just install at least a Oracle 10.2.0.4 version. This database can be on a different host. Step 2 The Repository Creation Utility The next step should be to run the Repository Creation Utility (RCU). This is a client application that just needs to connect to your database. It can be run on any host that can reach the database and is a Windows or Linux 32-bit machine. When you run it, be sure to install the OID schema and the OAM schema. If you miss one of these, you can run the RCU again to install the missing schema. Step 3 The Foundation With OFM 11g Oracle started to use WebLogic Server 11g (WLS) as its foundation for all OFM 11g installation. We therefore install it first. Depending on your operating system, it might be possible, that no native installer is available. My approach to this dilemma is to use the WLS Generic Installer for all my installations. It does not include a JDK either but if you have both for your platform you are ready to go. Step 3a The JDK To make things interesting, Oracle currently has two JDKs in its portfolio. The Sun JDK and the JRockit JDK. Both are available for a number of platforms. If you are lucky and both are available for your platform, install both in a separate directory (and not one of your ORACLE_HOMEs) each, You can use the later as you like. Step 3b Install WLS for OID and OAM With the JDK installed, we start the generic installer with java -jar wls_generic.jar.STOP! Before you do this, check the version first. It should be 1.6.0_18 or later and not the GCC one (Some Linux distros have it installed by default). To verify the version, issue a java -version command and make sure that the output does not contain the text gcj and the version matches. If this does not work, use an absolute path like /opt/java/jdk1.6.0_23/bin/java to start the installer. The installer allows you to specify a path to install the software into, say /opt/oracle/iam/11.1.1.3 for the OID and OAM installation. We will call this IAM_HOME. Step 4 Install OID Now we are ready to install OID. Start the OID installer (in the Disk1 directory) and just select the installation only step. This will install the software only and does not configure the instance. Use the IAM_HOME as the target directory. Step 5 Install SOA Suite The IAM 11g Suite uses the BPEL component of the SOA Suite 11g for its workflows. This is a pretty closed environment and not to be used for SCA Composites. We install the SOA Suite in $IAM_HOME/soa. The installer only installs the binaries. Configuration will be done later. Step 6 Install OAM Once the installation of OID and SOA is done, we are ready to install the OAM software in the same IAM_HOME. Make sure to install the OAM binaries in a directory different from the one you used during the OID and SOA installation. As before, we only install the software, the instance will be created later. Step 7 Backup the Installation At this point, I normally do a backup (or snapshot in a virtual image) of the installation. Good when you need to go back to this point. Step 8 Configure OID The software is installed and now we need instances to run it. This process is called configuration. For OID use the config.sh found in $IAM_HOME/oid/bin to start the configuration wizard. Normally this runs smoothly. If you encounter some issues check the Oracle Support site for help. This configuration will also start the OID instance. Step 9 Install the Oracle AS SSO Schema Before we install the Forms software we need to install the Oracle AS SSO Schema into the database and OID. This is a rather dangerous procedure, but fully documented in the IAM Installation Guide, Chapter 10. You should finish this in one go, do not reboot your host during the whole procedure. As a precaution, you should make a backup of the OID instance before you start the procedure. Once the backup is ready, read the chapter, including every note, carefully. You can avoid a number of issues by following all the steps and will succeed with a working solution. Step 10 Configure OAM Reached this step? Great. You are ready to create an OAM instance. Use the $IAM_HOME/iam/common/binconfig.sh for this. This will open the WLS Domain Creation Wizard and asks for the libraries to be installed. You should at least select the OAM with Database repository item. The configuration will also start the OAM instance. Step 11 Install WLS for Forms 11g It is quite tempting to install everything in one ORACLE_HOME. Unfortunately this does not work for all OFM packages. Therefore we do another WLS installation in another ORACLE_HOME. The same considerations as in step 3b apply. We call this one FORMS_HOME. Step 12 Install Forms In the FORMS_HOME we now install the binaries for the Forms 11g software. Again, this is a install only step. Configuration starts with the next step. Step 13 Configure Forms To configure Forms 11g we start the Configuration Wizard (config.sh) in FORMS_HOME/bin. This wizard should create a new WebLogic Domain and an OHS instance! Do not extend existing domains or instances! Forms should run in its own instances! When all information is supplied, the wizard will create the domain and instance and starts them automatically.Step 14 Setup your Forms SSO EnvironmentOnce you have implemented and tested your Forms 11g instance, you can configured it for SSO. Yes, this requires the old Oracle AS SSO solution, OIDDAS for creating and assigning users and SSO to setup your partner applications. In this step you should consider to create every user necessary for use within the environment. When done, do not forget to test it. Step 15 Migrate the SSO Repository Since the final goal is to get rid of the old SSO implementation we need to migrate the old SSO repository into the new OID structure. Additionally, this step will also migrate all partner application configurations into OAM 11g. Quite convenient. To do this step, you have to start the upgrade agent (ua or ua.bat or ua.cmd) on the operating system level in $IAM_HOME/bin. Once finished, this wizard will create new osso.conf files for each partner application in $IAM_HOME/upgrade/temp/oam/.Note: At the time of this writing, this step only works if everything is on the same host (ie. OID, OAM, etc.). This restriction might be lifted in later releases. Step 16 Change your OHS sso.conf and shut down OC4J_SECURITY In Step 14 we verified that SSO for our Forms environment works fine. Now, we are shutting the old system done and reconfigure the OHS that acts as the Forms entry point. First we go to the OHS configuration directory and rename the old osso.conf  to osso.conf.10g. Now we change the moduleconf/mod_osso.conf  to point to the new osso.conf file. Copy the new osso.conf  file from $IAM_HOME/upgrade/temp/oam/ to the OHS configuration directory. Restart OHS, test forms by using the same forms links. OAM should now kick in and show the login dialog to ask for your user credentials.Done. Now your Forms environment is successfully integrated with OAM 11g.Enjoy. What's Next? This rather lengthy setup is just the foundation for your growing environment of OAM 11g protections. In the next entry we will show that Forms 11g and ADF Faces 11g can use the same OAM installation and provide real single sign-on. References Nearly everything is documented. Use the documentation! Oracle® Fusion Middleware Installation Guide for Oracle Identity Management 11gR1 Oracle® Fusion Middleware Installation Guide for Oracle Identity Management 11gR1, Chapter 11-14 Oracle® Fusion Middleware Administrator's Guide for Oracle Access Manager 11gR1, Appendix B Oracle® Fusion Middleware Upgrade Guide for Oracle Identity Management 11gR1, Chapter 10   

  Read the article

• Boost bind function

  - by Gokul

  Hi, I have a abstract base class A and a set of 10 derived classes. The infix operator is overloaded in all of the derived classes class A{ void printNode( std::ostream& os ) { this->printNode_p(); } void printNode_p( std::ostream& os ) { os << (*this); } }; There is a container which stores the base class pointers. I want to use boost::bind function to call the overloaded infix operator in each of its derived class. I have written like this std::vector<A*> m_args .... std::ostream os; for_each( m_args.begin(), m_args.end(), bind(&A::printNode, _1, os) ); What is the problem with this code? Thanks, Gokul.

  Read the article

• Is WPF Decorator class useful?

  - by darja

  I need to create control to draw border around its child. So, I have created class and derived it from Decorator: class RoundedBoxDecorator : Decorator { protected override Size ArrangeOverride(Size arrangeSize) { //some source } protected override void OnRender(DrawingContext dc) { //some source } } It works fine, but I have some doubts about using Decorator as ancestor. I have found in MSDN that there are no special methods or properties in it, only derived from its ancestors (UIElement or FrameworkElement). ArrangeOverride and OnRender are also derived. So, what for Decorator class was designed and does it makes sense to use it? Or I can derive from FrameworkElement?

  Read the article

• Using implicit conversion as a substitute for multiple inheritance in .NET

  - by Daniel Plaisted

  I have a situation where I would like to have objects of a certain type be able to be used as two different types. If one of the "base" types was an interface this wouldn't be an issue, but in my case it is preferable that they both be concrete types. I am considering adding copies of the methods and properties of one of the base types to the derived type, and adding an implicit conversion from the derived type to that base type. Then users will be able treat the derived type as the base type by using the duplicated methods directly, by assigning it to a variable of the base type, or by passing it to a method that takes the base type. It seems like this solution will fit my needs well, but am I missing anything? Is there a situation where this won't work, or where it is likely to add confusion instead of simplicity when using the API?

  Read the article

< Previous Page | 30 31 32 33 34 35 36 37 38 39 40 41  | Next Page >