Search Results

Search found 6199 results on 248 pages for 'fast enumeration'.

Page 110/248 | < Previous Page | 106 107 108 109 110 111 112 113 114 115 116 117  | Next Page >

  • Enum "does not have a no-arg default constructor" with Jaxb and cxf

    - by Dave
    A client is having an issue running java2ws on some of their code, which uses & extends classes that are consumed from my SOAP web services. Confused yet? :) I'm exposing a SOAP web service (JBoss5, Java 6). Someone is consuming that web service with Axis1 and creating a jar out of it with the data types and client stubs. They are then defining their own type, which extends one of my types. My type contains an enumeration. class MyParent { private MyEnumType myEnum; // getters, settters for myEnum; } class TheirChild extends MyParent { ... } When they are running java2ws on their code (which extends my class), they get Caused by: com.sun.xml.bind.v2.runtime.IllegalAnnotationsException: 2 counts of IllegalAnnotationExceptions net.foo.bar.MyEnuMType does not have a no-arg default constructor. this problem is related to the following location: at net.foo.bar.MyEnumType at public net.foo.bar.MyEnumType net.foo.bar.MyParent.getMyEnum() The enum I've defined is below. This is now how it comes out after being consumed, but it's how I have it defined on the app server: @XmlType(name = "MyEnumType") @XmlEnum public enum MyEnumType { Val1("Val1"), Val2("Val2") private final String value; MyEnumType(String v) { value = v; } public String value() { return value; } public static MyEnumType fromValue(String v) { if (v == null || v.length() == 0) { return null; } if (v.equals("Val1")) { return MyEnumType.Val1; } if (v.equals("Val2")) { return MyEnumType.Val2; } return null; } } I've seen things online and other posts, like (this one) regarding Jaxb's inability to handle Lists or things like that, but I'm baffled about my enum. I'm pretty sure you can't have a default constructor for an enum (well, at least a public no-arg constructor, Java yells at me when I try), so I'm not sure what makes this error possible. Any ideas? Also, the "2 counts of IllegalAnnotationsExceptions" may be because my code actually has two enums that are written similarly, but I left them out of this example for brevity.

    Read the article

  • Prism - loading modules causes activation error

    - by Noich
    I've created a small Prism application (using MEF) with the following parts: - Infrastructure project, that contains a global file of region names. - Main project, that has 2 buttons to load other modules. - ModulesInterfaces project, where I've defined an IDataAccess interface for my DataAccess module. - DataAccess project, where there are several files but one main DataAccess class that implements both IDataAccess and IModule. When the user click a button, I want to show him a list of employees, so I need the DataAccess module. My code is as follows: var namesView = new EmployeesListView(); var namesViewModel = new EmployeesListViewModel(employeeRepository); namesView.DataContext = namesViewModel; namesViewModel.EmployeeSelected += EmployeeSelected; LocateManager(); manager.Regions["ContentRegion"].Add(new NoEmployeeView(), "noEmployee"); manager.Regions["NavigationRegion"].Add(namesView); I get an exception in my code when I'm trying to get DataAccess as a service (via ServiceLocator). I'm not sure if that's the right way to go, but trying to get it from the ModuleCatalog (as a type IDataAccess returns an empty enumeration). I'd appreciate some directions. Thanks. The problematic code line: object instance = ServiceLocator.Current.GetInstance(typeof(DataAccess.DataAccess)); The exact exception: Activation error occured while trying to get instance of type DataAccess, key "" The inner exception is null, the stack trace: at Microsoft.Practices.Prism.MefExtensions.MefServiceLocatorAdapter.DoGetInstance(Type serviceType, String key) in c:\release\WorkingDir\PrismLibraryBuild\PrismLibrary\Desktop\Prism.MefExtensions\MefServiceLocatorAdapter.cs:line 76 at Microsoft.Practices.ServiceLocation.ServiceLocatorImplBase.GetInstance(Type serviceType, String key) Edit The same exception is thrown for: container = (CompositionContainer)ServiceLocator.Current.GetInstance(typeof(CompositionContainer));

    Read the article

  • Generic wrapper for System.Web.Caching.Cache functions

    - by David Neale
    I've created a generic wrapper for using the Cache object: public class Cache<T> where T : class { public Cache Cache {get;set;} public CachedKeys Key {get;set;} public Cache(Cache cache, CachedKeys key){ Cache = cache; Key = key; } public void AddToCache(T obj){ Cache.Add(Key.ToString(), obj, null, DateTime.Now.AddMinutes(5), System.Web.Caching.Cache.NoSlidingExpiration, System.Web.Caching.CacheItemPriority.Normal, null); } public bool TryGetFromCache(out T cachedData) { cachedData = Cache[Key.ToString()] as T; return cachedData != null; } public void RemoveFromCache() { Cache.Remove(Key.ToString()); } } The CachedKeys enumeration is just a list of keys that can be used to cache data. The trouble is, to call it is quite convuluted: var cache = new Cache<MyObject>(Page.Cache, CachedKeys.MyKey); MyObject myObject = null; if(!cache.TryGetFromCache(out myObject)){ //get data... cache.AddToCache(data); //add to cache return data; } return myObject; I only store one instance of each of my objects in the cache. Therefore, is there any way that I can create an extension method that accepts the type of object to Cache and uses (via Reflection) its Name as the cache key? public static Cache<T> GetCache(this Cache cache, Type cacheType){ Cache<cacheType> Cache = new Cache<cacheType>(cache, cacheType.Name); } Of course, there's two errors here: Extension methods must be defined in a non-generic static class The type or namespace name 'cacheType' could not be found This is clearly not the right approach but I thought I'd show my working. Could somebody guide me in the right direction?

    Read the article

  • What is the best way to send structs containing enum values via sockets in C.

    - by Axel
    I've lots of different structs containing enum members that I have to transmit via TCP/IP. While the communication endpoints are on different operating systems (Windows XP and Linux) meaning different compilers (gcc 4.x.x and MSVC 2008) both program parts share the same header files with type declarations. For performance reasons, the structures should be transmitted directly (see code sample below) without expensively serializing or streaming the members inside. So the question is how to ensure that both compilers use the same internal memory representation for the enumeration members (i.e. both use 32-bit unsigned integers). Or if there is a better way to solve this problem... //type and enum declaration typedef enum { A = 1, B = 2, C = 3 } eParameter; typedef enum { READY = 400, RUNNING = 401, BLOCKED = 402 FINISHED = 403 } eState; #pragma pack(push,1) typedef struct { eParameter mParameter; eState mState; int32_t miSomeValue; uint8_t miAnotherValue; ... } tStateMessage; #pragma pack(pop) //... send via socket tStateMessage msg; send(iSocketFD,(void*)(&msg),sizeof(tStateMessage)); //... receive message on the other side tStateMessage msg_received; recv(iSocketFD,(void*)(&msg_received),sizeof(tStateMessage)); Additionally... Since both endpoints are little endian maschines, endianess is not a problem here. And the pack #pragma solves alignment issues satisfactorily. Thx for your answers, Axel

    Read the article

  • Retrieve data from .dat file.

    - by Zach
    We have an application which requires us to read data from a file (.dat) dynamically using deserialization. We are actually getting first object and it throws null pointer exception when we are accessing other objects using a "for" loop. File file=null; FileOutputStream fos=null; BufferedOutputStream bos=null; ObjectOutputStream oos=null; try{ file=new File("account4.dat"); fos=new FileOutputStream(file,true); bos=new BufferedOutputStream(fos); oos=new ObjectOutputStream(bos); oos.writeObject(m); System.out.println("object serialized"); amlist=new MemberAccountList(); oos.close(); } catch(Exception ex){ ex.printStackTrace(); } Reading objects: try{ MemberAccount m1; file=new File("account4.dat");//add your code here fis=new FileInputStream(file); bis=new BufferedInputStream(fis); ois=new ObjectInputStream(bis); System.out.println(ois.readObject()); while(ois.readObject()!=null){ m1=(MemberAccount)ois.readObject(); System.out.println(m1.toString()); }/mList.addElement(m1); // Here we have the issue throwing null pointer exception Enumeration elist=mList.elements(); while(elist.hasMoreElements()){ obj=elist.nextElement(); System.out.println(obj.toString()); }/ } catch(ClassNotFoundException e){ } catch(EOFException e){ System.out.println("end"); } catch(Exception ex){ ex.printStackTrace(); }

    Read the article

  • Exception during iteration on collection and remove items from that collection

    - by Muhammad Kashif Nadeem
    I remove item from ArrayList in foreach loop and get follwing exception. Collection was modified; enumeration operation may not execute. How can I remove items in foreach Following is my code: /* * Need to remove all items from 'attachementsFielPath' which does not exist in names array. */ try { string attachmentFileNames = txtAttachment.Text.Trim(); // Textbox having file names. string[] names = attachmentFileNames.Split(new char[] { ';' }); int index = 0; // attachmentsFilePath is ArrayList holding full path of fiels user selected at any time. foreach (var fullFilePath in attachmentsFilePath) { bool isNeedToRemove = true; // Extract filename from full path. string fileName = fullFilePath.ToString().Substring(fullFilePath.ToString().LastIndexOf('\\') + 1); for (int i = 0; i < names.Length; i++) { // If filename found in array then no need to check remaining items. if (fileName.Equals(names[i].Trim())) { isNeedToRemove = false; break; } } // If file not found in names array, remove it. if (isNeedToRemove) { attachmentsFilePath.RemoveAt(index); isNeedToRemove = true; } index++; } } catch (Exception ex) { throw ex; }

    Read the article

  • Maintain denormalized data with NHibernate EventListener

    - by Michael Valenty
    I have one bit of denormalized data used for performance reasons and I'm trying to maintain the data with an NHibernate event listener rather than a trigger. I'm not convinced this is the best approach, but I'm neck deep into it and I want to figure this out before moving on. I'm getting following error: System.InvalidOperationException : Collection was modified; enumeration operation may not execute. System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource) System.Collections.Generic.List`1.Enumerator.MoveNextRare() System.Collections.Generic.List`1.Enumerator.MoveNext() NHibernate.Engine.ActionQueue.ExecuteActions(IList list) NHibernate.Engine.ActionQueue.ExecuteActions() NHibernate.Event.Default.AbstractFlushingEventListener.PerformExecutions (IEventSource session) NHibernate.Event.Default.DefaultFlushEventListener.OnFlush(FlushEvent event) NHibernate.Impl.SessionImpl.Flush() NHibernate.Transaction.AdoTransaction.Commit() Here's the code to make happen: using (var tx = session.BeginTransaction()) { var business = session .Get<Business>(1234) .ChangeZipCodeTo("92011"); session.Update(business); tx.Commit(); // error happens here } and the event listener: public void OnPostUpdate(PostUpdateEvent @event) { var business = @event.Entity as Business; if (business != null) { var links = @event.Session .CreateQuery("select l from BusinessCategoryLink as l where l.Business.BusinessId = :businessId") .SetParameter("businessId", business.BusinessId) .List<BusinessCategoryLink>(); foreach (var link in links) { link.Location = business.Location; @event.Session.Update(link); } } }

    Read the article

  • Alternative Python standard library reference

    - by Ender
    I love Python; I absolutely despise its official documentation. Tutorials do not count as library references, but that appears to be what they're attempting. What I really want is the ability to find a class in the standard library and view documentation for all of its properties and methods. Actionscript, MSDN, and Java all do this just fine (although each with their odd quirks). Where is this for python? For example, I wanted to sort a list. mylist.sort(). Awesome. But what if I wanted it sorted in descending order? Official documentation is not - much - help. Or what if I wanted to specify a key function? That's also supported: mylist.sort(key=lamba item: item.customVar)- but documented...where? I understand that Python's approach to OOP may not be equivalent to Java et. al. Maybe list isn't actually a class - maybe it's just a function that returns an iterable when the tachyon beams are set to glorious and the unboxed hyper enumeration is quantized, but...I don't care. I just want to know how to sort lists. (Apologies for the angst - too much caffeine today)

    Read the article

  • Problem with detecting the value of the drop down list on the server (servlet) side

    - by Harry Pham
    Client code is pretty simple: <form action="DDServlet" method="post"> <input type="text" name="customerText"> <select id="customer"> <option name="customerOption" value="3"> Tom </option> <option name="customerOption" value="2"> Harry </option> </select> <input type="submit" value="send"> </form> Here is the code on the Servlet Enumeration paramNames = request.getParameterNames(); while(paramNames.hasMoreElements()){ String paramName = (String)paramNames.nextElement(); //get the next element System.out.println(paramName); } When I print out, I only see, customerText, but not customerOption. Any idea why guys? What I hope is, if I select Tom in my option, once I submit, on my servlet I should able to do this: String paramValues[] = request.getParameterValues(paramName); and get back value of 3

    Read the article

  • asp.net Membership : Extending Role membership?

    - by mark smith
    Hi there, I am been taking a look at asp.net membership and it seems to provide everything that i need but i need some kind of custom Role functionality. Currently i can add user to a role, great. But i also need to be able to add Permissions to Roles.. i.e. Role: Editor Permissions: Can View Editor Menu, Can Write to Editors Table, Can Delete Entries in Editors Table. Currently it doesn't support this, The idea behind this is to create a admin option in my program to create a role and then assign permissions to a role to say "allow the user to view a certain part of the application", "allow the user to open a menu item" Any ideas how i would implement soemthing like this? I presume a custom ROLE provider but i was wondering if some kind of framework extension existed already without rolling my own? Or anybody knows a good tutorial of how to tackle this issue? I am quite happy with what asp.net SQL provider has created in terms of tables etc... but i think i need to extend this by adding another table called RolesPermissions and then I presume :-) adding some kind of enumeration into the table for each valid permission?? THanks in advance

    Read the article

  • Understanding byte order and functions like CFSwapInt32HostToBig

    - by Typeoneerror
    I've got an enumeration in my game. A simple string message with an appended PacketType is being sent with the message (so it knows what to do with the message) over GameKit WIFI connection. I used Apple's GKRocket sample code as a starting point. The code itself is working fantastically; I just want to understand what the line with CFSwapInt32HostToBig is doing. What on earth does that do? and why does it need to do it? My guess is that it's making sure the PacketType value can be converted to an unsigned integer so it can send it reliably, but that doesn't sound all that correct to me. The documentation states "Converts a 32-bit integer from big-endian format to the host’s native byte order." but I don't understand what the means really. typedef enum { PacketTypeStart, // packet to notify games to start PacketTypeRequestSetup, // server wants client info PacketTypeSetup, // send client info to server PacketTypeSetupComplete, // round trip made for completion PacketTypeTurn, // packet to notify game that a turn is up PacketTypeRoll, // packet to send roll to players PacketTypeEnd // packet to end game } PacketType; // .... - (void)sendPacket:(NSData *)data ofType:(PacketType)type { NSLog(@"sendPacket:ofType(%d)", type); // create the data with enough space for a uint NSMutableData *newPacket = [NSMutableData dataWithCapacity:([data length]+sizeof(uint32_t))]; // Data is prefixed with the PacketType so the peer knows what to do with it. uint32_t swappedType = CFSwapInt32HostToBig((uint32_t)type); // add uint to data [newPacket appendBytes:&swappedType length:sizeof(uint32_t)]; // add the rest of the data [newPacket appendData:data]; // Send data checking for success or failure NSError *error; BOOL didSend = [_gkSession sendDataToAllPeers:newPacket withDataMode:GKSendDataReliable error:&error]; if (!didSend) { NSLog(@"error in sendDataToPeers: %@", [error localizedDescription]); } }

    Read the article

  • How to detect back button or forward button navigation in a silverlight navigation application

    - by parapura rajkumar
    When a Page is navigated to in silverlight you can override this method. protected override void OnNavigatedTo(NavigationEventArgs e) { base.OnNavigatedTo(e); } The NavigationEventArgs has a NavigationMode enumeration which is defined as public enum NavigationMode { New = 0, Back = 1, Forward = 2, Refresh = 3, } But calling e.NavigationMode always throws a NotImplementedException Is there a way in silverlight to detect a page is being navigated to because the user hit the forward/back browser button. What I am trying to achieve is some kind of state that can be preserved when the user hits the back button. For example assume you have a customer page which is showing a list of customers in a datagrid. The user can select a customer and there is a detail view which shows all the orders for that customer. Now within an order item you can click a hyperlink link that takes you to the shipping history of the order which is a separate page. When the user hits the back button I want to go back to the customers page and automatically select the customer he was viewing. Is this possible at all ? I also tried out the fragment navigation feature NavigationService.Navigate(new Uri("#currentcustomerid=" + customer.Id.ToString(), UriKind.Relative)); when the customer selection changes but this adds too many items to the history when the user clicks various customers on the customer page. EDIT There is also an method you can override protected override void OnNavigatingFrom(NavigatingCancelEventArgs e) { } which is the same as handling the NavigationService.Navigating event as indicated by BugFinder's answer. In this method e.NavigationMode always returns New when when you hit the Back or Forward Button. The only time this method returns Back is when you explicitly call NavigationService.GoBack()

    Read the article

  • SFINAE failing with enum template parameter

    - by zeroes00
    Can someone explain the following behaviour (I'm using Visual Studio 2010). header: #pragma once #include <boost\utility\enable_if.hpp> using boost::enable_if_c; enum WeekDay {MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY}; template<WeekDay DAY> typename enable_if_c< DAY==SUNDAY, bool >::type goToWork() {return false;} template<WeekDay DAY> typename enable_if_c< DAY!=SUNDAY, bool >::type goToWork() {return true;} source: bool b = goToWork<MONDAY>(); compiler this gives error C2770: invalid explicit template argument(s) for 'enable_if_c<DAY!=6,bool>::type goToWork(void)' and error C2770: invalid explicit template argument(s) for 'enable_if_c<DAY==6,bool>::type goToWork(void)' But if I change the function template parameter from the enum type WeekDay to int, it compiles fine: template<int DAY> typename enable_if_c< DAY==SUNDAY, bool >::type goToWork() {return false;} template<int DAY> typename enable_if_c< DAY!=SUNDAY, bool >::type goToWork() {return true;} Also the normal function template specialization works fine, no surprises there: template<WeekDay DAY> bool goToWork() {return true;} template<> bool goToWork<SUNDAY>() {return false;} To make things even weirder, if I change the source file to use any other WeekDay than MONDAY or TUESDAY, i.e. bool b = goToWork<THURSDAY>(); the error changes to this: error C2440: 'specialization' : cannot convert from 'int' to 'const WeekDay' Conversion to enumeration type requires an explicit cast (static_cast, C-style cast or function-style cast)

    Read the article

  • What is the name of this geometrical function?

    - by Spike
    In a two dimentional integer space, you have two points, A and B. This function returns an enumeration of the points in the quadrilateral subset bounded by A and B. A = {1,1} B = {2,3} Fn(A,B) = {{1,1},{1,2},{1,3},{2,1},{2,2},{2,3}} I can implement it in a few lines of LINQ. private void UnknownFunction(Point to, Point from, List<Point> list) { var vectorX = Enumerable.Range(Math.Min(to.X, from.X), Math.Abs(to.X - from.Y) + 1); var vectorY = Enumerable.Range(Math.Min(to.Y, from.Y), Math.Abs(to.Y - from.Y) + 1); foreach (var x in vectorX) foreach (var y in vectorY) list.Add(new Point(x, y)); } I'm fairly sure that this is a standard mathematical operation, but I can't think what it is. Feel free to tell me that it's one line of code in your language of choice. Or to give me a cunning implementation with lambdas or some such. But mostly I just want to know what it's called. It's driving me nuts. It feels a little like a convolution, but it's been too long since I was at school for me to be sure.

    Read the article

  • Error while opening port in Java

    - by Deepak
    I am getting the following error while trying to open the cash drawer. Error loading win32com: java.lang.UnsatisfiedLinkError: C:\Program Files\Java\jdk1.6.0_15\jre\bin\win32com.dll: Can't load IA 32-bit .dll on a AMD 64-bit platform The code i am using is as follows `import javax.comm.; import java.util.; /** Check each port to see if it is open. **/ public class openPort { public static void main (String [] args) { Enumeration port_list = CommPortIdentifier.getPortIdentifiers (); while (port_list.hasMoreElements ()) { // Get the list of ports CommPortIdentifier port_id = (CommPortIdentifier) port_list.nextElement (); // Find each ports type and name if (port_id.getPortType () == CommPortIdentifier.PORT_SERIAL) { System.out.println ("Serial port: " + port_id.getName ()); } else if (port_id.getPortType () == CommPortIdentifier.PORT_PARALLEL) { System.out.println ("Parallel port: " + port_id.getName ()); } else System.out.println ("Other port: " + port_id.getName ()); // Attempt to open it try { CommPort port = port_id.open ("PortListOpen",20); System.out.println (" Opened successfully"); port.close (); } catch (PortInUseException pe) { System.out.println (" Open failed"); String owner_name = port_id.getCurrentOwner (); if (owner_name == null) System.out.println (" Port Owned by unidentified app"); else // The owner name not returned correctly unless it is // a Java program. System.out.println (" " + owner_name); } } } //main } // PortListOpen`

    Read the article

  • XSD any element

    - by ofer shwartz
    HI! I'm trying to create a list that some of the elements are defined and some are not, without priority to order. I tried it this way, with an any element: <?xml version="1.0"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:complexType name="object" mixed="true"> <xs:choice> <xs:element name="value" minOccurs="1" maxOccurs="1"> <xs:simpleType> <xs:restriction base="xs:integer"> <xs:enumeration value="1"/> </xs:restriction> </xs:simpleType> </xs:element> <xs:any namespace="##any" processContents="skip"/> </xs:choice> </xs:complexType> <xs:element name="object" type="object"/> </xs:schema> And it tells me this error: :0:0: error: complex type 'object' violates the unique particle attribution rule in its components 'value' and '##any' Can someone help me out solve the problem? Ofer

    Read the article

  • Strategy Pattern with Type Reflection affecting Performances ?

    - by Aurélien Ribon
    Hello ! I am building graphs. A graph consists of nodes linked each other with links (indeed my dear). In order to assign a given behavior to each node, I implemented the strategy pattern. class Node { public BaseNodeBehavior Behavior {get; set;} } As a result, in many parts of the application, I am extensively using type reflection to know which behavior a node is. if (node.Behavior is NodeDataOutputBehavior) workOnOutputNode(node) .... My graph can get thousands of nodes. Is type reflection greatly affecting performances ? Should I use something else than the strategy pattern ? I'm using strategy because I need behavior inheritance. For example, basically, a behavior can be Data or Operator, a Data behavior can IO, Const or Intermediate and finally an IO behavior can be Input or Output. So if I use an enumeration, I wont be able to test for a node behavior to be of data kind, I will need to test it to be [Input, Output, Const or Intermediate]. And if later I want to add another behavior of Data kind, I'm screwed, every data-testing method will need to be changed.

    Read the article

  • How to allow one thread to mutate an array property while another thread iterates on a copy of the a

    - by Steve918
    I would like to implement an observer pattern in Objective-C where the observer implements an interface similar to SKPaymentTransactionObserver and the observable class just extends my base observable. My observable class looks something like what is below. Notice I'm making copies of the observers before enumeration to avoid throwing an exception . I've tried adding an NSLock around add observers and notify observers, but I run into a deadlock. What would be the proper way to handle concurrency when observers are being added as notifications are being sent? @implementation Observable -(void)notifyObservers:(SEL)selector { @synchronized(self) { NSSet* observer_copy = [observers copy]; for (id observer in observer_copy) { if([observer respondsToSelector: selector]) { [observer performSelector: selector]; } } [observer_copy release]; } } -(void)notifyObservers:(SEL)selector withObject:(id)arg1 withObject:(id)arg2 { @synchronized(self) { NSSet* observer_copy = [observers copy]; for (id observer in observer_copy) { if([observer respondsToSelector: selector]) { [observer performSelector: selector withObject: arg1 withObject: arg2]; } } [observer_copy release]; } } -(void)addObserver:(id)observer { @synchronized(self) { [observers addObject: observer]; } } -(void)removeObserver:(id)observer { @synchronized(self) { [observers removeObject: observer]; } }

    Read the article

  • Existing LINQ extension method similar to Parallel.For?

    - by Joel Martinez
    The linq extension methods for ienumerable are very handy ... but not that useful if all you want to do is apply some computation to each item in the enumeration without returning anything. So I was wondering if perhaps I was just missing the right method, or if it truly doesn't exist as I'd rather use a built-in version if it's available ... but I haven't found one :-) I could have sworn there was a .ForEach method somewhere, but I have yet to find it. In the meantime, I did write my own version in case it's useful for anyone else: using System.Collections; using System.Collections.Generic; public delegate void Function<T>(T item); public delegate void Function(object item); public static class EnumerableExtensions { public static void For(this IEnumerable enumerable, Function func) { foreach (object item in enumerable) { func(item); } } public static void For<T>(this IEnumerable<T> enumerable, Function<T> func) { foreach (T item in enumerable) { func(item); } } } usage is: myEnumerable.For<MyClass>(delegate(MyClass item) { item.Count++; });

    Read the article

  • How can I store an inventory-like list of numbers?

    - by Rachel
    I've got a list of number that I need to keep track of. The numbers are loosely related, but represent distinctly different items. I'd like to keep a list of the numbers but be able to refer to them by name so that I can call them and use them where needed easily. Kind of like an inventory listing, where the numbers all refer to a part ID and I'd like to call them idPart1, idPart2, idPart3 so their purpose is easily identifiable when they are used. What would be the best way to do this? 1)Define a structure. Say, PartIds. A number of int members will be included, part1, part2 etc. To use, an instance of the structure will be created, values assigned to the members, and the numbers will be used by saying struct.member as needed. 2)Define an enumeration. Use part1, part2 as the enum literals. Store the actual values in a vector or list, each one at the index corresponding to the value of the number's name within the enum. Use the enum literals to retrieve the values, list[enumLit]. 3)Something completely different There's nothing else I need to do with the numbers - just look them up every once in a while. Since there's no processing, I kind of think a new class for them is overkill, but I'm willing to be convinced otherwise. Any suggestions?

    Read the article

  • ControlCollection extension method optimazation

    - by Johan Leino
    Hi, got question regarding an extension method that I have written that looks like this: public static IEnumerable<T> FindControlsOfType<T>(this ControlCollection instance) where T : class { T control; foreach (Control ctrl in instance) { if ((control = ctrl as T) != null) { yield return control; } foreach (T child in FindControlsOfType<T>(ctrl.Controls)) { yield return child; } } } public static IEnumerable<T> FindControlsOfType<T>(this ControlCollection instance, Func<T, bool> match) where T : class { return FindControlsOfType<T>(instance).Where(match); } The idea here is to find all controls that match a specifc criteria (hence the Func<..) in the controls collection. My question is: Does the second method (that has the Func) first call the first method to find all the controls of type T and then performs the where condition or does the "runtime" optimize the call to perform the where condition on the "whole" enumeration (if you get what I mean). secondly, are there any other optimizations that I can do to the code to perform better. An example can look like this: var checkbox = this.Controls.FindControlsOfType<MyCustomCheckBox>( ctrl => ctrl.CustomProperty == "Test" ) .FirstOrDefault();

    Read the article

  • What is the preferred way in C++ for converting a builtin type (int) to bool?

    - by Martin
    When programming with Visual C++, I think every developer is used to see the warning warning C4800: 'BOOL' : forcing value to bool 'true' or 'false' from time to time. The reason obviously is that BOOL is defined as int and directly assigning any of the built-in numerical types to bool is considered a bad idea. So my question is now, given any built-in numerical type (int, short, ...) that is to be interpreted as a boolean value, what is the/your preferred way of actually storing that value into a variable of type bool? Note: While mixing BOOL and bool is probably a bad idea, I think the problem will inevitably pop up whether on Windows or somewhere else, so I think this question is neither Visual-C++ nor Windows specific. Given int nBoolean; I prefer this style: bool b = nBoolean?true:false; The following might be alternatives: bool b = !!nBoolean; bool b = (nBoolean != 0); Is there a generally preferred way? Rationale? I should add: Since I only work with Visual-C++ I cannot really say if this is a VC++ specific question or if the same problem pops up with other compilers. So it would be interesting to specifically hear from g++ or users how they handle the int-bool case. Regarding Standard C++: As David Thornley notes in a comment, the C++ Standard does not require this behavior. In fact it seems to explicitly allow this, so one might consider this a VC++ weirdness. To quote the N3029 draft (which is what I have around atm.): 4.12 Boolean conversions [conv.bool] A prvalue of arithmetic, unscoped enumeration, pointer, or pointer to member type can be converted to a prvalue of type bool. A zero value, null pointer value, or null member pointer value is converted to false; any other value is converted to true. (...)

    Read the article

  • Is there really such a thing as a char or short in modern programming?

    - by Dean P
    Howdy all, I've been learning to program for a Mac over the past few months (I have experience in other languages). Obviously that has meant learning the Objective C language and thus the plainer C it is predicated on. So I have stumbles on this quote, which refers to the C/C++ language in general, not just the Mac platform. With C and C++ prefer use of int over char and short. The main reason behind this is that C and C++ perform arithmetic operations and parameter passing at integer level, If you have an integer value that can fit in a byte, you should still consider using an int to hold the number. If you use a char, the compiler will first convert the values into integer, perform the operations and then convert back the result to char. So my question, is this the case in the Mac Desktop and IPhone OS environments? I understand when talking about theses environments we're actually talking about 3-4 different architectures (PPC, i386, Arm and the A4 Arm variant) so there may not be a single answer. Nevertheless does the general principle hold that in modern 32 bit / 64 bit systems using 1-2 byte variables that don't align with the machine's natural 4 byte words doesn't provide much of the efficiency we may expect. For instance, a plain old C-Array of 100,000 chars is smaller than the same 100,000 ints by a factor of four, but if during an enumeration, reading out each index involves a cast/boxing/unboxing of sorts, will we see overall lower 'performance' despite the saved memory overhead?

    Read the article

  • What should I do if i have a factory method which requires different parameters for different implem

    - by Sam Holder
    I have an interface, IMessage and a class which have several methods for creating different types of message like so: class MessageService { IMessage TypeAMessage(param 1, param 2) IMessage TypeBMessage(param 1, param 2, param 3, param 4) IMessage TypeCMessage(param 1, param 2, param 3) IMessage TypeDMessage(param 1) } I don't want this class to do all the work for creating these messages so it simply delegates to a MessageCreatorFactory which produces an IMessageCreator depending on the type given (an enumeration based on the type of the message TypeA, TypeB, TypeC etc) interface IMessageCreator { IMessage Create(MessageParams params); } So I have 4 implementations of IMessageCreator: TypeAMessageCreator, TypeBMessageCreator, TypeCMessageCreator, TypeDMessageCreator I ok with this except for the fact that because each type requires different parameters I have had to create a MessageParams object which contains 4 properties for the 4 different params, but only some of them are used in each IMessageCreator. Is there an alternative to this? One other thought I had was to have a param array as the parameter in the Create emthod, but this seems even worse as you don't have any idea what the params are. Or to create several overloads of Create in the interface and have some of them throw an exception if they are not suitable for that particular implementation (ie you called a method which needs more params, so you should have called one of the other overloads.) Does this seem ok? Is there a better solution?

    Read the article

  • How to read data from file(.dat) in append mode

    - by govardhan
    We have an application which requires us to read data from a file (.dat) dynamically using deserialization. We are actually getting first object and it throws null pointer exception and "java.io.StreamCorruptedException:invalid type code:AC" when we are accessing other objects using a "for" loop. File file=null; FileOutputStream fos=null; BufferedOutputStream bos=null; ObjectOutputStream oos=null; try{ file=new File("account4.dat"); fos=new FileOutputStream(file,true); bos=new BufferedOutputStream(fos); oos=new ObjectOutputStream(bos); oos.writeObject(m); System.out.println("object serialized"); amlist=new MemberAccountList(); oos.close(); } catch(Exception ex){ ex.printStackTrace(); } Reading objects: try{ MemberAccount m1; file=new File("account4.dat");//add your code here fis=new FileInputStream(file); bis=new BufferedInputStream(fis); ois=new ObjectInputStream(bis); System.out.println(ois.readObject()); **while(ois.readObject()!=null){ m1=(MemberAccount)ois.readObject(); System.out.println(m1.toString()); }/*mList.addElement(m1);** // Here we have the issue throwing null pointer exception Enumeration elist=mList.elements(); while(elist.hasMoreElements()){ obj=elist.nextElement(); System.out.println(obj.toString()); }*/ } catch(ClassNotFoundException e){ } catch(EOFException e){ System.out.println("end"); } catch(Exception ex){ ex.printStackTrace(); }

    Read the article

< Previous Page | 106 107 108 109 110 111 112 113 114 115 116 117  | Next Page >