Search Results

Search found 13880 results on 556 pages for 'explicit interface'.

Page 148/556 | < Previous Page | 144 145 146 147 148 149 150 151 152 153 154 155  | Next Page >

• Modifying SQL Database on Shared Hosting

  - by apocalypse9

  I have a live database on a shared hosting server. I am making some major changes to my site's code and I would like to fix some stupid mistakes I made in initially designing the database. These changes involve altering the size of a large number of fields, and enforcing referential integrity between tables properly. I would like to make the changes on both my local test server and the remote server if possible. I should note that while I'm fairly comfortable with writing complex queries to handle data, I have very little experience modifying database structure without a graphical interface. I can access the remote database in the visual studio database explorer but I can not use that for anything other than data manipulation. I installed Sql Management Studio express last night and after 40+ crashes I gave up - I couldn't even patch the damn thing. The remote server is SQL 2005 / The MyLittleAdmin web interface is available. So my question is what is the best way to accomplish these changes. Is there a graphical interface I can use on the remote server? If not is there an easy way to copy the database to my local machine, fix it, and re upload? Finally if none of the above are viable does anyone have links to a decent info on fixing referential integrity via query? Sorry for the somewhat general question - I feel like I am making this far harder than it should be but after searching / trying all night i haven't gotten anywhere. Thanks in advance for the help. I really appreciate it. ...Also does anyone have a time machine I can borrow- I need to go kick my past self's ass for this.

  Read the article

• NSProgressIndicator woes - perhaps my NSView subclass?

  - by mootymoots

  Hi All I have created a basic application, created a subclassed NSView, and added it as a custom view in interface builder. All works ok. However certain things do not work correctly, which makes me wonder if my NSView is subclassed correctly? Specifically, when using an NSProgressIndicator, I can use startAnimating: and stopAnimating on an indeterminate, but if I try and do anything with a determinate with incrementBy it does nothing. Even if I set the default value of the determinate NSProgressIndicator to 50.0, it appears when the app is launched at 0.0, despite looking good in IB. My NSProgressIndicator is hooked up correctly as an IBOutlet, I can tell it to hide etc, just can't get it to animate at all. However, I also have other issues that make me think that this problem is actually my NSView subclass (such as Quick Look not firing). In my subclass I've simply overridden the initWithFrame: and drawRect methods, calling their [super]. As I said, I've then placed this as a custom view in interface builder and changed it to MyCustomView. All works fine mostly...? Am I subclassing this incorrectly, or not doing something in interface builder correctly? I seem to be missing some small thing?!

  Read the article

• GWT - problems with constants in css

  - by hba

  Hi, I'm new to GWT; I'm building a small sample app. I have several CSS files. I'm able to successfully use the ClientBundle and CssResource to assign styles to the elements defined in my UiBinder script. Now I'd like to take it one step further and introduce CSS constants using @def css-rule. The @def works great when I define a constant and use it in the same CSS file. However I cannot use it in another CSS file. When I try to use the @eval rule to evaluate an existing constant the compiler throws an execption: "cannot make a static reference to the non-static method ". Here is an example of what I'm trying to do: ConstantStyle.css @def BACKGROUND red; ConstantStyle.java package abc; import ...; interface ConstantStyle extends cssResource { String BACKGROUND(); } MyStyle.css @eval BACKGROUND abc.ConstantStyle.BACKGROUND(); .myClass {background-color: BACKGROUND;} MyStyle.java package abc; import ...; interface ConstantStyle extends cssResource { String myClass; } MyResources.java package abc; import ...; interface MyResources extends ClientBundle { @Source("ConstantStyle.css") ConstantStyle constantStyle(); @Source("MyStyle.css") MyStyle myStyle(); } Thanks in advance!

  Read the article

• Using child visitor in C#

  - by Thomas Matthews

  I am setting up a testing component and trying to keep it generic. I want to use a generic Visitor class, but not sure about using descendant classes. Example: public interface Interface_Test_Case { void execute(); void accept(Interface_Test_Visitor v); } public interface Interface_Test_Visitor { void visit(Interface_Test_Case tc); } public interface Interface_Read_Test_Case : Interface_Test_Case { uint read_value(); } public class USB_Read_Test : Interface_Read_Test_Case { void execute() { Console.WriteLine("Executing USB Read Test Case."); } void accept(Interface_Test_Visitor v) { Console.WriteLine("Accepting visitor."); } uint read_value() { Console.WriteLine("Reading value from USB"); return 0; } } public class USB_Read_Visitor : Interface_Test_Visitor { void visit(Interface_Test_Case tc) { Console.WriteLine("Not supported Test Case."); } void visit(Interface_Read_Test_Case rtc) { Console.WriteLine("Not supported Read Test Case."); } void visit(USB_Read_Test urt) { Console.WriteLine("Yay, visiting USB Read Test case."); } } // Code fragment USB_Read_Test test_case; USB_Read_Visitor visitor; test_case.accept(visitor); What are the rules the C# compiler uses to determine which of the methods in USB_Read_Visitor will be executed by the code fragment? I'm trying to factor out dependencies of my testing component. Unfortunately, my current Visitor class contains visit methods for classes not related to the testing component. Am I trying to achieve the impossible?

  Read the article

• How do I export a package symbol to a namespace in Perl?

  - by Mike

  I'm having trouble understanding how to export a package symbol to a namespace. I've followed the documentation almost identically, but it seems to not know about any of the exporting symbols. mod.pm #!/usr/bin/perl package mod; use strict; use warnings; require Exporter; @ISA = qw(Exporter); @EXPORT=qw($a); our $a=(1); 1; test.pl $ cat test.pl #!/usr/bin/perl use mod; print($a); This is the result of running it $ ./test.pl Global symbol "@ISA" requires explicit package name at mod.pm line 10. Global symbol "@EXPORT" requires explicit package name at mod.pm line 11. Compilation failed in require at ./test.pl line 3. BEGIN failed--compilation aborted at ./test.pl line 3. $ perl -version This is perl, v5.8.4 built for sun4-solaris-64int

  Read the article

• Trying to make a plugin system in C++

  - by Pirate for Profit

  I'm making a task-based program that needs to have plugins. Tasks need to have properties which can be easily edited, I think this can be done with Qt's Meta-Object Compiler reflection capabilities (I could be wrong, but I should be able to stick this in a QtPropertyBrowser?) So here's the base: class Task : public QObject { Q_OBJECT public: explicit Task(QObject *parent = 0) : QObject(parent){} virtual void run() = 0; signals: void taskFinished(bool success = true); } Then a plugin might have this task: class PrinterTask : public Task { Q_OBJECT public: explicit PrinterTask(QObject *parent = 0) : Task(parent) {} void run() { Printer::getInstance()->Print(this->getData()); // fictional emit taskFinished(true); } inline const QString &getData() const; inline void setData(QString data); Q_PROPERTY(QString data READ getData WRITE setData) // for reflection } In a nutshell, here's what I want to do: // load plugin // find all the Tasks interface implementations in it // have user able to choose a Task and edit its specific Q_PROPERTY's // run the TASK It's important that one .dll has multiple tasks, because I want them to be associated by their module. For instance, "FileTasks.dll" could have tasks for deleting files, making files, etc. The only problem with Qt's plugin setup is I want to store X amount of Tasks in one .dll module. As far as I can tell, you can only load one interface per plugin (I could be wrong?). If so, the only possible way to do accomplish what I want is to create a FactoryInterface with string based keys which return the objects (as in Qt's Plug-And-Paint example), which is a terrible boilerplate that I would like to avoid. Anyone know a cleaner C++ plugin architecture than Qt's to do what I want? Also, am I safely assuming Qt's reflection capabilities will do what I want (i.e. able to edit an unknown dynamically loaded tasks' properties with the QtPropertyBrowser before dispatching)?

  Read the article

• Cocoa - calling a VIEW method from the CONTROLLER

  - by eemerge

  Hello everyone, Got a little problem i asked about it before but maybe i didnt ask properly. I have a cocoa application, which amongst other things, must do the following task: - load some images from the disk, store them in an array and display them in a custom view. In the Interface Builder i have a CustomView and an OBJECT that points to TexturesController.h The custom view is a custom class, TextureBrowser. Below is the code for the controller and view: TexturesController #import <Cocoa/Cocoa.h> @class TextureBrowser; @interface TexturesController : NSObject { IBOutlet NSTextField *logWindow; IBOutlet TextureBrowser *textureView; NSMutableArray *textureList; } @property textureView; -(IBAction)loadTextures:(id)sender; -(IBAction)showTexturesInfo:(id)sender; @end TextureBrowser @interface TextureBrowser : NSView { NSMutableArray *textures; } @property NSMutableArray *textures; -(void)loadTextureList:(NSMutableArray *)source; @end These are just the headers. Now , what i need to do is: when loadTextures from the TexturesController is called, after i load the images i want to send this data to the view (TextureBrowser), for example, store it in the NSMutableArray *textures. I tried using the -(void)loadTextureList:(NSMutableArray*)source method from the view, but in the TextureController.m i get a warning : No -loadTextureList method found This is how i call the method : [textureView loadTextureList: textureList]; And even if i run it with the warning left there, the array in the view class doesnt get initialised. Maybe im missing something...maybe someone can give a simple example of what i need to do and how to do it (code). Thanks in advance.

  Read the article

• Getting an updated location in Android

  - by jul

  Hi, I'm using the code shown below to get an updated value for location every time a button is clicked. When my activity is resumed I get an update every second, so that when I call getLastKnownLocation I expect to have a location that have been updated in the last second. Is that the correct way to do that? I would expect the onLocationChanged event to be triggered every time I execute a 'geo fix' command (or max after 1s since I request update every 1s), but it's only triggered the first time. Why? Any help/suggestion welcome! Thanks package org.digitalfarm.atable; ... public class Atable extends Activity { private Button mSearchButton; private TextView mytext; private LocationManager locationManager; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mSearchButton = (Button)this.findViewById(R.id.button); mytext = (TextView) findViewById(R.id.dude); locationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE); final Criteria criteria = new Criteria(); criteria.setAccuracy(Criteria.ACCURACY_FINE); mSearchButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { String provider = locationManager.getBestProvider(criteria, true); Location location = locationManager.getLastKnownLocation(provider); } }); } //Start a location listener LocationListener onLocationChange=new LocationListener() { public void onLocationChanged(Location loc) { //sets and displays the lat/long when a location is provided String latlong = "Lat: " + loc.getLatitude() + " Long: " + loc.getLongitude(); mytext.setText(latlong); } public void onProviderDisabled(String provider) { // required for interface, not used } public void onProviderEnabled(String provider) { // required for interface, not used } public void onStatusChanged(String provider, int status, Bundle extras) { // required for interface, not used } }; //pauses listener while app is inactive @Override public void onPause() { super.onPause(); locationManager.removeUpdates(onLocationChange); } //reactivates listener when app is resumed @Override public void onResume() { super.onResume(); locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,1000,100.0f,onLocationChange); } }

  Read the article

• Controlling the alpha of a UIImageView with Slider ..Can' t get it

  - by user1824839

  first i' d like to say this Forum was really helpfull for me that just started coding some weeks ago .. I succeed to do a quite nice app for the moment , than, but i m stuck on this : HOW COULD I CONTROL THE ALPHA OF A UIIMAGEVIEW , WITH A SLIDER EMBEDED IN ANOTHER VIEW ??? ; Basically i' like to do like the alpha slider of this : http://www.edumobile.org/iphone/how-to-make-an-app-2/controlling-a-uiviews-properties-for-ipad/ , but for a UIImageView. I promised i searched for hours , and didnt find how to do it ... Could someone have some minutes to give me ideas ?? Sorry for my poor english too. Thanks if you can. L. The resume of the link i posted, only focussing on the alpha property would be : ( considering a UIView ( View ) embeded in a ViewController ( ViewController ): enter code here ----View.h----- @interface View : UIView @property ( nonatomic, assign ) CGFloat alpha; @end enter code here ----View.m---- @implementation View @synthesize alpha; ?} @end enter code here ------ViewController.h----- import "View.h" @interface ViewController : UIViewController @property (nonatomic, strong) IBOutlet View *view; ?- (IBAction)alphaChanged:(UISlider *)sender; @end enter code here -------ViewController.m------ @interface ViewController () @end @implementation ViewController @synthesize view; (View *)view {?     if (!view) {?        view = [[View alloc] init];?    }?    return view;?} enter code here (IBAction)redChanged:(UISlider *)sender? {?    self.circle.alpha = sender.value;?    [self.circle setNeedsDisplay];?} (void)viewDidLoad ?{?    [super viewDidLoad];?         ?    self.circle.alpha = (CGFloat)1;?} (void)didReceiveMemoryWarning? {?  [super didReceiveMemoryWarning];?    @end enter code here

  Read the article

• C++ Namespaces & templates question

  - by Kotti

  Hi! I have some functions that can be grouped together, but don't belong to some object / entity and therefore can't be treated as methods. So, basically in this situation I would create a new namespace and put the definitions in a header file, the implementation in cpp file. Also (if needed) I would create an anonymous namespace in that cpp file and put all additional functions that don't have to be exposed / included to my namespace's interface there. See the code below (probably not the best example and could be done better with another program architecture, but I just can't think of a better sample...) Sample code (header) namespace algorithm { void HandleCollision(Object* object1, Object* object2); } Sample code (cpp) #include "header" // Anonymous namespace that wraps // routines that are used inside 'algorithm' methods // but don't have to be exposed namespace { void RefractObject(Object* object1) { // Do something with that object // (...) } } namespace algorithm { void HandleCollision(Object* object1, Object* object2) { if (...) RefractObject(object1); } } So far so good. I guess this is a good way to manage my code, but I don't know what should I do if I have some template-based functions and want to do basically the same. If I'm using templates, I have to put all my code in the header file. Ok, but how should I conceal some implementation details then? Like, I want to hide RefractObject function from my interface, but I can't simply remove it's declaration (just because I have all my code in a header file)... The only approach I came up with was something like: Sample code (header) namespace algorithm { // Is still exposed as a part of interface! namespace impl { template <typename T> void RefractObject(T* object1) { // Do something with that object // (...) } } template <typename T, typename Y> void HandleCollision(T* object1, Y* object2) { impl::RefractObject(object1); // Another stuff } } Any ideas how to make this better in terms of code designing?

  Read the article

• Is is possible to do an end-run around generics covariance in C# < 4 in this hypothetical situation?

  - by John Feminella

  Suppose I have a small inheritance hierarchy of Animals: public interface IAnimal { string Speak(); } public class Animal : IAnimal { public Animal() {} public string Speak() { return "[Animal] Growl!"; } } public class Ape : IAnimal { public string Speak() { return "[Ape] Rawrrrrrrr!"; } } public class Bat : IAnimal { public string Speak() { return "[Bat] Screeeeeee!"; } } Next, here's an interface offering a way to turn strings into IAnimals. public interface ITransmogrifier<T> where T : IAnimal { T Transmogrify(string s); } And finally, here's one strategy for doing that: public class Transmogrifier<T> : ITransmogrifier<T> where T : IAnimal, new() { public T Transmogrify(string s) { T t = default(T); if (typeof(T).Name == s) t = new T(); return t; } } Now, the question. Is it possible to replace the sections marked [1], [2], and [3] such that this program will compile and run correctly? If you can't do it without touching parts other than [1], [2], and [3], can you still get an IAnimal out of each instance of a Transmogrifier in a collection containing arbitrary implementations of an IAnimal? Can you even form such a collection to begin with? static void Main(string[] args) { var t = new Transmogrifier<Ape>(); Ape a = t.Transmogrify("Ape"); Console.WriteLine(a.Speak()); // Works! // But can we make an arbitrary collection of such animals? var list = new List<Transmogrifier< [1] >>() { // [2] }; // And how about we call Transmogrify() on each one? foreach (/* [3] */ transmogrifier in list) { IAnimal ia = transmogrifier.Transmogrify("Bat"); } } }

  Read the article

• Data layer refactoring

  - by Joey

  I've taken control of some entity framework code and am looking to refactor it. Before I do, I'd like to check my thoughts are correct and I'm not missing the entity-framework way of doing things. Example 1 - Subquery vs Join Here we have a one-to-many between As and Bs. Apart from the code below being hard to read, is it also inefficient? from a in dataContext.As where ((from b in dataContext.Bs where b.Text.StartsWith(searchText) select b.AId).Distinct()).Contains(a.Id) select a Would it be better, for example, to use the join and do something like this? from a in dataContext.As where a.Bs.Any(b => b.Text.StartsWith(searchText)) select a Example 2 - Explicit Joins vs Navigation Here we have a one-to-many between As and Bs and a one-to-many between Bs and Cs. from a in dataContext.As join b in dataContext.Bs on b.AId equals a.Id join c in dataContext.Cs on c.BId equals b.Id where c.SomeValue equals searchValue select a Is there a good reason to use explicit joins rather than navigating through the data model? For example: from a in dataContext.As where a.Bs.Any(b => b.Cs.Any(c => c.SomeValue == searchValue) select a

  Read the article

• Generic Constraints And Type Parameters Mess

  - by Dummy01

  Hi everyone, I have the following base abstract class defined as: public abstract class BaseObject<T> : IComparable, IComparable<T>, IEquatable<T> {} I also have an interface defined as: public interface ICode<T> where T : struct { T Code { get; } } Now I want to derive a class that is inherited from BaseObject<T> and includes interface ICode<T>. I tried to define it like that: public class DerivedObject<T, U> : BaseObject<T>, ICode<U> where T : DerivedObject<T, U> where U : struct { public DerivedObject(U code) { Code = code; } // From BaseObject protected override int InstanceCompareTo(T obj) { return Code.CompareTo(obj.Code); } // From BaseObject protected override bool InstanceEquals(T obj) { return Code.Equals(obj.Code); } // From ICode U _Code; public U Code { get { return _Code; } protected set { _Code = value; } } } The only error that comes from the compiler is for Code.CompareTo(obj.Code) with the message: 'U' does not contain a definition for 'CompareTo' and no extension method 'CompareTo' accepting a first argument of type 'U' could be found. But U is a value type and should know CompareTo. Have you any idea what I am doing wrong, or if I do all wrong? My final aim is to derive classes such these: public class Account : DerivedObject<Account, int> public class ItemGroup : DerivedObject<ItemGroup, string> Big Thanks In Advance!

  Read the article

• Can JMX operations take interfaces as parameters?

  - by Thor84no

  I'm having problems with an MBean that takes a Map<String, Object> as a parameter. If I try to execute it via JMX using a proxy object, I get an Exception: Caused by: javax.management.ReflectionException at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:231) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:668) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) Caused by: java.lang.IllegalArgumentException: Unable to find operation updateProperties(java.util.HashMap) It appears that it attempts to use the actual implementation class rather than the interface, and doesn't check if this is a child of the required interface. The same thing happens for extended classes (for example declare HashMap, pass in LinkedHashMap). Does this mean it's impossible to use an interface for such methods? At the moment I'm getting around it by changing the method signature to accept a HashMap, but it seems odd that I wouldn't be able to use interfaces (or extended classes) in my MBeans. Edit: The proxy object is being created by an in-house utility class called JmxInvocationHandler. The (hopefully) relevant parts of it are as follows: public class JmxInvocationHandler implements InvocationHandler { ... public static <T> T createMBean(final Class<T> iface, SFSTestProperties properties, String mbean, int shHostID) { T newProxyInstance = (T) Proxy.newProxyInstance(iface.getClassLoader(), new Class[] { iface }, (InvocationHandler) new JmxInvocationHandler(properties, mbean, shHostID)); return newProxyInstance; } ... private JmxInvocationHandler(SFSTestProperties properties, String mbean, int shHostID) { this.mbeanName = mbean + MBEAN_SUFFIX + shHostID; msConfig = new MsConfiguration(properties.getHost(0), properties.getMSAdminPort(), properties.getMSUser(), properties.getMSPassword()); } ... public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { if (management == null) { management = ManagementClientStore.getInstance().getManagementClient(msConfig.getHost(), msConfig.getAdminPort(), msConfig.getUser(), msConfig.getPassword(), false); } final Object result = management.methodCall(mbeanName, method.getName(), args == null? new Object[] {} : args); return result; } }

  Read the article

• WCF: get generic type object (e.g. MyObject<T>) from remote machine

  - by Aaron

  I have two applications that are communicating through WCF. On the server the following object exists: public class MyObject<T> { ... public Entry<T> GetValue() } Where Entry<T> is another object with T Data as a public property. T could be any number of types (string, double, etc) On the client I have ClientObject<T> that needs to get the value of Data from the server (same type). Since I'm using WCF, I have to define my ServiceContract as an interface, and I can't have ClientObject<T> call Entry<T> GetMyObjectValue (string Name) which calls GetValue on the correct MyObject<T> because my interface isn't aware of the type information. I've tried implementing separate GetValue functions (GetMyObjectValueDouble, GetMyObjectValueString) in the interface and then have ClientObject determine the correct one to call. However, Entry<T> val = (Entry<T>)GetMyObjectValueDouble(...); doesn't work because it's not sure about the type information. How can I go about getting a generic object over WCF with the correct type information? Let me know if there are other details I can provide. Thanks!

  Read the article

• Repository Pattern Standardization of methods

  - by Nix

  All I am trying to find out the correct definition of the repository pattern. My original understanding was this (extremely dubmed down) Separate your Business Objects from your Data Objects Standardize access methods in data access layer. I have really seen 2 different implementations. Implementation 1 : public Interface IRepository<T>{ List<T> GetAll(); void Create(T p); void Update(T p); } public interface IProductRepository: IRepository<Product> { //Extension methods if needed List<Product> GetProductsByCustomerID(); } Implementation 2 : public interface IProductRepository { List<Product> GetAllProducts(); void CreateProduct(Product p); void UpdateProduct(Product p); List<Product> GetProductsByCustomerID(); } Notice the first is generic Get/Update/GetAll, etc, the second is more of what I would define "DAO" like. Both share an extraction from your data entities. Which I like, but i can do the same with a simple DAO. However the second piece standardize access operations I see value in, if you implement this enterprise wide people would easily know the set of access methods for your repository. Am I wrong to assume that the standardization of access to data is an integral piece of this pattern ? Rhino has a good article on implementation 1, and of course MS has a vague definition and an example of implementation 2 is here.

  Read the article

• Loading GWT Messages from a Database

  - by Lars Tackmann

  In GWT one typically loads i18n strings using a interface like this: public interface StatusMessage extends Messages { String error(String username); : } which then loads the actual strings from a StatusMessage.property file: error=User: {0} does not have access to resource This is a great solution, however my client is unbendable in his demand for putting the i18n strings in a database so they can be changed at runtime (though its not a requirement that they be changed realtime). One solution is to create a async service which takes a message ID and user locale and returns a string. I have implemented this and find it terribly ugly (and it introduces a huge amount of extra communication with the server, plus it makes property placeholder replacement rather complicated). So my question is this, can I in some nice way implement a custom message provider that loads the messages from the backend in one big swoop (for the current user session). If it can also hook into the default GWT message mechanism, then I would be completely happy (i.e. so I can create a interface like above and keep using the the nice {0}, {1}... property replacement format). Other suggestions for clean database driven messages in GWT are also welcome.

  Read the article

• C++ and Dependency Injection in unit testing

  - by lhumongous

  Suppose I have a C++ class like so: class A { public: A() { } void SetNewB( const B& _b ) { m_B = _b; } private: B m_B; } In order to unit test something like this, I would have to break A's dependency on B. Since class A holds onto an actual object and not a pointer, I would have to refactor this code to take a pointer. Additionally, I would need to create a parent interface class for B so I can pass in my own fake of B when I test SetNewB. In this case, doesn't unit testing with dependency injection further complicate the existing code? If I make B a pointer, I'm now introducing heap allocation, and some piece of code is now responsible for cleaning it up (unless I use ref counted pointers). Additionally, if B is a rather trivial class with only a couple of member variables and functions, why introduce a whole new interface for it instead of just testing with an instance of B? I suppose you could make the argument that it would be easier to refactor A by using an interface. But are there some cases where two classes might need to be tightly coupled?

  Read the article

• Can a conforming C# compiler optimize away a local (but unused) variable if it is the only strong re

  - by stakx

  The title says it all, but let me explain: void Case_1() { var weakRef = new WeakReference(new object()); GC.Collect(); // <-- doesn't have to be an explicit call; just assume that // garbage collection would occur at this point. if (weakRef.IsAlive) ... } In this code example, I obviously have to plan for the possibility that the new'ed object is reclaimed by the garbage collector; therefore the if statement. (Note that I'm using weakRef for the sole purpose of checking if the new'ed object is still around.) void Case_2() { var unusedLocalVar = new object(); var weakRef = new WeakReference(unusedLocalVar); GC.Collect(); // <-- doesn't have to be an explicit call; just assume that // garbage collection would occur at this point. Debug.Assert(weakReferenceToUseless.IsAlive); } The main change in this code example from the previous one is that the new'ed object is strongly referenced by a local variable (unusedLocalVar). However, this variable is never used again after the weak reference (weakRef) has been created. Question: Is a conforming C# compiler allowed to optimize the first two lines of Case_2 into those of Case_1 if it sees that unusedLocalVar is only used in one place, namely as an argument to the WeakReference constructor? i.e. is there any possibility that the assertion in Case_2 could ever fail?

  Read the article

• how to emulate thread local storage at user space in C++ ?

  - by vprajan

  I am working on a mobile platform over Nucleus RTOS. It uses Nucleus Threading system but it doesn't have support for explicit thread local storage i.e, TlsAlloc, TlsSetValue, TlsGetValue, TlsFree APIs. The platform doesn't have user space pthreads as well. I found that __thread storage modifier is present in most of the C++ compilers. But i don't know how to make it work for my kind of usage. How does __thread keyword can be mapped with explicit thread local storage? I read many articles but nothing is so clear for giving me the following basic information will __thread variable different for each thread ? How to write to that and read from it ? does each thread has exactly one copy of the variable ? following is the pthread based implementation: pthread_key_t m_key; struct Data : Noncopyable { Data(T* value, void* owner) : value(value), owner(owner) {} int* value; }; inline ThreadSpecific() { int error = pthread_key_create(&m_key, destroy); if (error) CRASH(); } inline ~ThreadSpecific() { pthread_key_delete(m_key); // Does not invoke destructor functions. } inline T* get() { Data* data = static_cast<Data*>(pthread_getspecific(m_key)); return data ? data->value : 0; } inline void set(T* ptr) { ASSERT(!get()); pthread_setspecific(m_key, new Data(ptr, this)); } How to make the above code use __thread way to set & get specific value ? where/when does the create & delete happen? If this is not possible, how to write custom pthread_setspecific, pthread_getspecific kind of APIs. I tried using a C++ global map and index it uniquely for each thread and retrieved data from it. But it didn't work well.

  Read the article

• Complicated API issue with calling assemblies dynamically?

  - by Stefanos Tses

  I have an interesting challenge that I'm wondering if anyone here can give me some direction. I'm writing a .Net windows forms application that runs on a network and uses an SQL Server to save and pull data. I want to offer a mini "plugin" API, where developers can build their own assemblies and implement a specific interface (IDataManipulate). These assemblies then can be used by my application to call the interface functions and do something. I can create assemblies using my API, copy the file to a folder in my local hard drive and configure my application to use Reflection to call a specific function from the implemented interface (IDataManipulate.Execute). The problem: Since the application will be installed in multiple workstations in the network, is impossible to copy the plugin dlls the users will create to each machine. Solutions I tried: Solution 1 Copy the API dll to a network share. Problem: Requires AllowPartiallyTrustedCallersAttribute, which requires .Net singing, which I can't force from my users. Solution 2 (preferred) Serialize the dll object, save it to the database, deserialize it and call IDataManipulate.Execute. Problem: After deserialization, I try cast it to a IDataManipulate object but returns an error looking for the actual dll file. Solution 3 Save the dll bytes as byte[] to the database and recreate the dll at the local PC every time the user starts my application. Problem: Dll may have dependencies, which I don't know if I can detect. Any suggestions will be greatly appreciated. Thanks

  Read the article

• Writing my own implementation of stl-like Iterator in C++.

  - by Negai

  Good evening everybody, I'm currently trying to understand the intrinsics of iterators in various languages i.e. the way they are implemented. For example, there is the following class exposing the list interface. template<class T> class List { public: virtual void Insert( int beforeIndex, const T item ) throw( ListException ) =0 ; virtual void Append( const T item ) =0; virtual T Get( int position ) const throw( ListException ) =0; virtual int GetLength() const =0; virtual void Remove( int position ) throw( ListException ) =0; virtual ~List() =0 {}; }; According to GoF, the best way to implement an iterator that can support different kinds of traversal is to create the base Iterator class (friend of List) with protected methods that can access List's members. The concrete implementations of Iterator will handle the job in different ways and access List's private and protected data through the base interface. From here forth things are getting confusing. Say, I have class LinkedList and ArrayList, both derived from List, and there are also corresponding iterators, each of the classes returns. How can I implement LinkedListIterator? I'm absolutely out of ideas. And what kind of data can the base iterator class retrieve from the List (which is a mere interface, while the implementations of all the derived classes differ significantly) ? Sorry for so much clutter. Thanks.

  Read the article

• File write not getting updated in Qt 4.5.3

  - by user249490

  Hi, I have an XML file. My application requires manipulation into that XML file. I will be writing the values into the XML value. I also have interface to display the read contents of the file. The user might add values into that XML (through an interface). Without closing the application he may decide to display the File contents also. Now the problem is, after i write the XML contents into the file, when i view the file through the interface , the values are not getting updated. After i close the application and open it the updated values are available.I am using the following code to achieve this. For writing QXmlStreamWriter and for reading QDomDocument, QDomNodeList. After i complete the writing, I flush and close the file too. lFile.flush(); lFile.close(); After reading also i closed the file. Can someone tell me what am doing wrong??

  Read the article

• Intelligent search and generation of Java code, preferrably using Python?

  - by Ipsquiggle

  Basically, I do lots of one-off code generation, large-scale refactorings, etc. etc. in Java. My tool language of choice is Python, but I'll take whatever solutions you can offer. Here is a simplified illustration of what I would like, in a pseudocode Generating an implementation for an interface search within my project: for each Interface as iName: write class(name=iName+"Impl", implements=iName) search within the body of iName: for each Method as mName: write method(name=mName, body="// TODO implement this...") Basically, the tool I'm searching for would allow me to: parse files according to their Java structure ("search for interfaces") search for words contextualized by language elements and types ("variables of type SomeClass", "doStuff() method calls on SomeClass instances") to run searches with structural context ("within the body of the current result") easily replace or generate code (with helpers to generate, as above, or functions for replacing, "rename the interface to Foo", "insert the line Blah.Blah()", etc.) The point is, I don't want to spend a lot of time writing these things, as they are usually throwaway. But sometimes I need something just a little smarter than what grep offers. It wouldn't be too hard to write up a simplistic version of this, but if I'm going to use something like this at all, I'd expect it to be robust. Any suggestions of a tool/library that will help me accomplish this?

  Read the article

• C#: Determine Type for (De-)Serialization

  - by dbemerlin

  Hi, i have a little problem implementing some serialization/deserialization logic. I have several classes that each take a different type of Request object, all implementing a common interface and inheriting from a default implementation: This is how i think it should be: Requests interface IRequest { public String Action {get;set;} } class DefaultRequest : IRequest { public String Action {get;set;} } class LoginRequest : DefaultRequest { public String User {get;set;} public String Pass {get;set;} } Handlers interface IHandler<T> { public Type GetRequestType(); public IResponse HandleRequest(IModel model, T request); } class DefaultHandler<T> : IHandler<T> // Used as fallback if the handler cannot be determined { public Type GetRequestType() { return /* ....... how to get the Type of T? ((new T()).GetType()) ? .......... */ } public IResponse HandleRequest(IModel model, T request) { /* ... */ } } class LoginHandler : DefaultHandler<LoginRequest> { public IResponse HandleRequest(IModel mode, LoginRequest request) { } } Calling class Controller { public ProcessRequest(String action, String serializedRequest) { IHandler handler = GetHandlerForAction(action); IRequest request = serializer.Deserialize<handler.GetRequestType()>(serializedRequest); handler(this.Model, request); } } Is what i think of even possible? My current Solution is that each handler gets the serialized String and is itself responsible for deserialization. This is not a good solution as it contains duplicate code, the beginning of each HandleRequest method looks the same (FooRequest request = Deserialize(serializedRequest); + try/catch and other Error Handling on failed deserialization). Embedding type information into the serialized Data is not possible and not intended. Thanks for any Hints.

  Read the article

< Previous Page | 144 145 146 147 148 149 150 151 152 153 154 155  | Next Page >