Search Results

Search found 5705 results on 229 pages for 'observer pattern'.

Page 37/229 | < Previous Page | 33 34 35 36 37 38 39 40 41 42 43 44  | Next Page >

  • Null Reference Exception on MVVM pattern

    - by Mohit Deshpande
    System.NullReferenceException Object reference not set to an instance of an object. at Microsoft.Windows.Design.DocumentModel.Trees.MarkupDocumentTreeManager.<FindMarkupNodePath>d__0.MoveNext() at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable1 source) at MS.Internal.Services.DocumentInformationServiceImpl.get_Root() at MS.Internal.Designer.VSDesigner.Load() at MS.Internal.Designer.VSIsolatedDesigner.VSIsolatedView.Load() at MS.Internal.Designer.VSIsolatedDesigner.VSIsolatedDesignerFactory.Load(IsolatedView view) at MS.Internal.Host.Isolation.IsolatedDesigner.BootstrapProxy.LoadDesigner(IsolatedDesignerFactory factory, IsolatedView view) at MS.Internal.Host.Isolation.IsolatedDesigner.BootstrapProxy.LoadDesigner(IsolatedDesignerFactory factory, IsolatedView view) at MS.Internal.Host.Isolation.IsolatedDesigner.Load() at MS.Internal.Designer.DesignerPane.LoadDesignerView() I keep getting this exception and then intellisense stops working in a XAML text editor. Any ideas why?

    Read the article

  • Avoiding EXC_BAD_ACCESS when using the delegate pattern

    - by Kenny Winker
    A have a view controller, and it creates a "downloader" object, which has a reference to the view controller (as a delegate). The downloader calls back the view controller if it successfully downloads the item. This works fine as long as you stay on the view, but if you navigate away before the download is complete I get EXC_BAD_ACCESS. I understand why this is happening, but is there any way to check if an object is still allocated? I tried to test using delegate != nil, and [delegate respondsToSelector:], but it chokes. if (!self.delegate || ![self.delegate respondsToSelector:@selector(downloadComplete:)]) { // delegate is gone, go away quietly [self autorelease]; return; } else { // delegate is still around [self.delegate downloadComplete:result]; } I know I could, a) have the downloader objects retain the view controller b) keep an array of downloaders in the view controller, and set their delegate values to nil when I deallocate the view controller. But I wonder if there is an easier way, where I just test if the delegate address contains a valid object?

    Read the article

  • how to fix: ctags null expansion of name pattern "\1"

    - by bua
    Hi, As the title points I have problem with ctags when trying to parse user-defined language. Basically I've followed those instructions. The quickest and easiest way to do this is by defining a new language using the program options. In order to have Swine support available every time I start ctags, I will place the following lines into the file $HOME/.ctags, which is read in every time ctags starts: --langdef=swine --langmap=swine:.swn --regex-swine=/^def[ \t]*([a-zA-Z0-9_]+)/\1/d,definition/ The first line defines the new language, the second maps a file extension to it, and the third defines a regular expression to identify a language definition and generate a tag file entry for it. I've tried different flags: b,e for regex. My definition of tag is: --regex-q=/^[ \t]*[^[:space:]]*[:space:]*:[:space:]*{/\l/f,function/b When I replace \1 with anything else (ascii caracter set ), It works. the output is: (--regex-q=/^[ \t]*[^[:space:]]*[:space:]*:[:space:]*{/my function name/f,function/b) !_TAG_FILE_FORMAT 2 /extended format; --format=1 will not append ;" to lines/ !_TAG_FILE_SORTED 1 /0=unsorted, 1=sorted, 2=foldcase/ !_TAG_PROGRAM_AUTHOR Darren Hiebert /[email protected]/ !_TAG_PROGRAM_NAME Exuberant Ctags // !_TAG_PROGRAM_URL http://ctags.sourceforge.net /official site/ !_TAG_PROGRAM_VERSION 5.8 // my function name file.q /^.ras.getLocation:{[u]$/;" f my function name file.q /^.a.getResource:{[u; pass]$/;" f my function name file.q /^.a.init:{$/;" f my function name file.q /^.a.kill:{[u; force]$/;" f my function name file.q /^.asdf.status:{[what; u]$/;" f my function name file.q /^.pc:{$/;" f Why \1 doesn't work? (I've tried all 1-9)

    Read the article

  • MVC and repository pattern data efficiency

    - by Shawn Mclean
    My project is structured as follows: DAL public IQueryable<Post> GetPosts() { var posts = from p in context.Post select p; return posts; } Service public IList<Post> GetPosts() { var posts = repository.GetPosts().ToList(); return posts; } //Returns a list of the latest feeds, restricted by the count. public IList<PostFeed> GetPostFeeds(int latestCount) { List<Post> post - GetPosts(); //CODE TO CREATE FEEDS HERE return feeds; } Lets say the GetPostFeeds(5) is supposed to return the 5 latest feeds. By going up the list, doesn't it pull down every single post from the database from GetPosts(), just to extract 5 from it? If each post is say 5kb from the database, and there is 1 million records. Wont that be 5GB of ram being used per call to GetPostFeeds()? Is this the way it happens? Should I go back to my DAL and write queries that return only what I need?

    Read the article

  • .NET Membership with Repository Pattern

    - by Zac
    My team is in the process of designing a domain model which will hide various different data sources behind a unified repository abstraction. One of the main drivers for this approach is the very high probability that these data sources will undergo significant change in the near future and we don't want to be re-writing business logic when this happens. One data source will be our membership database which was originally implemented using the default ASP.Net Membership Provider. The membership provider is tied to the System.Web.Security namespace but we have a design guideline requiring that our domain model layer is not dependent upon System.Web (or any other implementation/environment dependency) as it will be consumed in different environments - nor do we want our websites directly communicating with databases. I am considering what would be a good approach to reconciling the MembershipProvider approach with our abstracted n-tier architecture. My initial feeling is that we could create a "DomainMembershipProvider" which interacts with the domain model and then implement objects in the model which deal with the repository and handle validation/business logic. The repository would then implement data access using our (as-yet undecided) ORM/data access tool. Are there are any glaring holes in this approach - I haven't worked closely with the MembershipProvider class so may well be missing something. Alternatively, is there an approach that you think will better serve the requirements I described above? Thanks in advance for your thoughts and advice. Regards, Zac

    Read the article

  • Interface design pattern / Java / Seam

    - by Walter White
    Hi all, Is this possible somehow? @Name("geolocationService") public interface GeolocationService { @Query("SELECT g FROM Geolocation geolocation INNER JOIN geolocation.deployment deployment WHERE geolocation.ipStart <= INET_ATON(:ipAddress) AND deployment.active = TRUE") Geolocation findByIpAddress(@NamedParameter("ipAddress")final String ipAddress); } public GeolocationAction { @In private GeolocationService geolocationService; @RequestParameter("ipAddress") private String ipAddress; @Out private Geolocation geolocation; public void find() { geolocation = geolocationService.findByIpAddress(ipAddress); } } Is it possible to do this without implementing the interface? What is required to make that work? I want to maintain less and do more. If I can intercept invocations of the geolocationService then I am golden, how would I do that? I don't want it to ever be instantiated, so it will always be null (I don't want the @Name and @In annotations either then). Walter

    Read the article

  • Regex pattern help for phrase OR a character set

    - by andybaird
    I have a PHP regex that I want to fail if the matched word after /blog is just "feed". This MUST be done within the regex itself, not using any other PHP syntax. The regex currently looks like this: blog/([a-zA-Z0-9-]+) What would I add to this to properly negate the regex if "feed" is found after blog/ ?

    Read the article

  • Why is there ambiguity in this diamond pattern?

    - by cambr
    #include <iostream> using namespace std; class A { public: void eat(){ cout<<"A";} }; class B: public A { public: void eat(){ cout<<"B";} }; class C: public A { public: void eat(){ cout<<"C";} }; class D: public B,C { public: void eat(){ cout<<"D";} }; int main(){ A *a = new D(); a->eat(); } I am not sure this is called diamond problem or not, but why doesn't this work? When I said, a->eat() (remember eat() is not virtual), there is only one possible eat() to call, that of A. Why then, do I get this error: 'A' is an ambiguous base of 'D'

    Read the article

  • Example with Visitor Pattern

    - by devoured elysium
    public class Song { public string Genre { get; protected set; } public string Name { get; protected set; } public string Band { get; protected set; } public Song(string name, string band, string genre) { Name = name; Genre = genre; Band = band; } } public interface IMusicVisistor { void Visit(List<Song> items); } public class MusicLibrary { List<Song> _songs = new List<Song> { ...songs ... }; public void Accept(IMusicVisitor visitor) { visitor.Visit(_songs); } } and now here's one Visitor I made: public class RockMusicVisitor : IMusicVisitor { public List<Song> Songs { get; protected set; } public void Visit(List<Song> items) { Songs = items.Where(x => x.Genre == "Rock").ToList(); } } Why is this any better than just putting a public property Songs and then letting any kind of class do with it anything that it wants to? This example comes from this post.

    Read the article

  • Factory Pattern - when do you say you need a specialised factory

    - by dbones
    Hi, I am having a little design crisis, I am making a Plane class, which is made of an engine 2 wings and N seats The engine takes in a engine size, and the wings have a span. would this still be feasible to have a PlaneFactory, when the factory may have to take in multiple parameters to setup the plane (wings, engine, no of seats) thanks in advance bones

    Read the article

  • how to identify an html div id which starts with some pattern using jquery

    - by dexter
    normally we use something like this to identify Id using jquery $("#PhotoId").html('some html'); here we get the html (say div) having id 'PhotoId' what if the id is partially dynamic i.e. lets say there are multiple photoes each id would start with 'PhotoId' EX. $("#PhotoId" + result.Id).html(some html'); NOW, i want to identify html(div) which starts with 'PhotoId' how can it be done

    Read the article

  • MVC pattern and State Machine

    - by topright
    I think of a game as a state machine. Game States separate I/O processing, game logic and rendering into different classes: while (game_loop) { game->state->io_events(this); game->state->logic(this); game->state->rendering(); } You can easily change a game state in this approach. MVC separation works in more complex way: while (game_loop) { game->cotroller->io_events(this); game->model->logic(this); game->view->rendering(); } So changing Game States becomes error prone task (switch 3 MVC objects, not 1). What are practical ways of combining these 2 concepts?

    Read the article

  • testing dao with hibernate genericdao pattern with spring.Headache

    - by black sensei
    Hello good fellas! in my journey of learning hibernate i came across an article on hibernate site. i' learning spring too and wanted to do certain things to discover the flexibility of spring by letting you implement you own session.yes i don't want to use the hibernateTemplate(for experiment). and i'm now having a problem and even the test class.I followed the article on the hibernate site especially the section an "implementation with hibernate" so we have the generic dao interface : public interface GenericDAO<T, ID extends Serializable> { T findById(ID id, boolean lock); List<T> findAll(); List<T> findByExample(T exampleInstance); T makePersistent(T entity); void makeTransient(T entity); } it's implementation in an abstract class that is the same as the one on the web site.Please refer to it from the link i provide.i'll like to save this post to be too long now come my dao's messagedao interface package com.project.core.dao; import com.project.core.model.MessageDetails; import java.util.List; public interface MessageDAO extends GenericDAO<MessageDetails, Long>{ //Message class is on of my pojo public List<Message> GetAllByStatus(String status); } its implementation is messagedaoimpl: public class MessageDAOImpl extends GenericDAOImpl <Message, Long> implements MessageDAO { // mySContainer is an interface which my HibernateUtils implement mySContainer sessionManager; /** * */ public MessageDAOImpl(){} /** * * @param sessionManager */ public MessageDAOImpl(HibernateUtils sessionManager){ this.sessionManager = sessionManager; } //........ plus other methods } here is my HibernatUtils public class HibernateUtils implements SessionContainer { private final SessionFactory sessionFactory; private Session session; public HibernateUtils() { this.sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory(); } public HibernateUtils(SessionFactory sessionFactory) { this.sessionFactory = sessionFactory; } /** * * this is the function that return a session.So i'm free to implements any type of session in here. */ public Session requestSession() { // if (session != null || session.isOpen()) { // return session; // } else { session = sessionFactory.openSession(); // } return session; } } So in my understanding while using spring(will provide the conf), i'ld wire sessionFactory to my HiberbernateUtils and then wire its method RequestSession to the Session Property of the GenericDAOImpl (the one from the link provided). here is my spring config core.xml <bean id="sessionManager" class="com.project.core.dao.hibernate.HibernateUtils"> <constructor-arg ref="sessionFactory" /> </bean> <bean id="messageDao" class="com.project.core.dao.hibernate.MessageDAOImpl"> <constructor-arg ref="sessionManager"/> </bean> <bean id="genericDAOimpl" class="com.project.core.dao.GenericDAO"> <property name="session" ref="mySession"/> </bean> <bean id="mySession" factory-bean="com.project.core.dao.SessionContainer" factory-method="requestSession"/> now my test is this public class MessageDetailsDAOImplTest extends AbstractDependencyInjectionSpringContextTests{ HibernateUtils sessionManager = (HibernateUtils) applicationContext.getBean("sessionManager"); MessageDAO messagedao =(MessageDAO) applicationContext.getBean("messageDao"); static Message[] message = new Message[] { new Message("text",1,"test for dummies 1","1234567890","Pending",new Date()), new Message("text",2,"test for dummies 2","334455669990","Delivered",new Date()) }; public MessageDAOImplTest() { } @Override protected String[] getConfigLocations(){ return new String[]{"file:src/main/resources/core.xml"}; } @Test public void testMakePersistent() { System.out.println("MakePersistent"); messagedao.makePersistent(message[0]); Session session = sessionManager.RequestSession(); session.beginTransaction(); MessageDetails fromdb = ( Message) session.load(Message.class, message[0].getMessageId()); assertEquals(fromdb.getMessageId(), message[0].getMessageId()); assertEquals(fromdb.getDateSent(),message.getDateSent()); assertEquals(fromdb.getGlobalStatus(),message.getGlobalStatus()); assertEquals(fromdb.getNumberOfPages(),message.getNumberOfPages()); } i'm having this error exception in constructor testMakePersistent(java.lang.NullPointerException at com.project.core.dao.hibernate.MessageDAOImplTest) with this stack : at com.project.core.dao.hibernate.MessageDAOImplTest.(MessageDAOImplTest.java:28) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at junit.framework.TestSuite.createTest(TestSuite.java:61) at junit.framework.TestSuite.addTestMethod(TestSuite.java:283) at junit.framework.TestSuite.(TestSuite.java:146) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.run(JUnitTestRunner.java:481) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.launch(JUnitTestRunner.java:1031) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.main(JUnitTestRunner.java:888) )) How to actually make this one work.I know this is a lot to stuffs and i'm thanking you for reading it.Please give me a solution.How would you do this? thanks

    Read the article

  • I've got a ComboBox that's giving me grief in WPF using the MVVM pattern

    - by Mike
    Here's my code: <ComboBox Grid.Column="1" Grid.Row="9" ItemsSource="{Binding Path=PriorityEntries}" SelectedItem="{Binding Path=Priority,Mode=TwoWay}"/> The comboBox is bound properly with PriorityEntries, and when i change the value of the comboBox the "set" of the bound property(Priority) is called setting it to what it needs to be. However, when i close the UserControl that this combobox resides, it calls the set property again with a value of null and then sets what the selectedItem was to null. Why is the comboBox being bound again when I close the usercontrol. I tried setting the mode to OneTime, but that won't reflect any changes...

    Read the article

  • how to achieve xxx.blogspot.com URL pattern ??

    - by abc
    Consider the case of blogspot.com the domain is the one blogspot.com only but suppose i register in it with xxx then i will have xxx.blogspot.com like wise here it won't be the subdomain (i can smell) , but its some thing different ... how to achieve this ?? in j2ee web application..

    Read the article

  • What is your "favorite" anti pattern?

    - by Omar Kooheji
    By favorite I mean the one that gets your goat the most, not the one you enjoy using the most. I'm fairly new to the concept of anti patterns and I'd like a list of do not do's. An explanation of why it's an antipattern and what problems it causes would be good too.

    Read the article

  • Complex User Interface -> MVC pattern

    - by glenn.danthi
    I have been reading a lot on MVC/MVP patterns.... I have a simple question....If you have a view with loads of controls....say 10 texboxes and 10 checkboxes....etc etc... Am I expected to specify the properties and events each one of them in my IView interface?....

    Read the article

  • How to configure the roles in my tomcat application to work with JNDI(WIN AUTH)

    - by Itay Levin
    Hi, I'm trying to change the authentication mode of my application from JDBC-REALM to JNDI-REALM. I configured the following section inside the Server.xml <Realm className="org.apache.catalina.realm.JNDIRealm" debug="99" connectionURL="ldap://****:389/DC=onsetinc,DC=com??sAMccountName?sub?(objectClass=*)" connectionName="[email protected]" connectionPassword="password" userBase="CN=Users" referrals="follow" userSearch="(sAMAccountName={0})" userSubtree="true" roleBase="CN=Users" roleName="name" roleSubtree="true" roleSearch="(member={1})"/> I have also configured the web.xml under my appfolder to contain the following: <security-role> <role-name>Admin</role-name> </security-role> <security-role> <role-name>WaterlooUsers</role-name> </security-role> <security-constraint> <web-resource-collection> <web-resource-name>Tube</web-resource-name> <url-pattern>/ComposeMessage.jsp</url-pattern> <url-pattern>/PageStatus.jsp</url-pattern> <url-pattern>/UserStatus.jsp</url-pattern> <url-pattern>/SearchEC.jsp</url-pattern> <url-pattern>/SearchEC2.jsp</url-pattern> <url-pattern>/SearchMessageStatisticsEC.jsp</url-pattern> <url-pattern>/SearchMessageStatus.jsp</url-pattern> <url-pattern>/SearchMessageStatisticsPager.jsp</url-pattern> <url-pattern>/SearchPageStatus.jsp</url-pattern> </web-resource-collection> <auth-constraint> <role-name>WaterlooUsers</role-name> </auth-constraint> </security-constraint> In my Active directory i have created a new group called WaterlooUsers It's distinguish name is : distinguishedName: CN=WaterlooUsers,CN=Users,DC=onsetinc,DC=com It has a property member which contains the following user: member: CN=Itay Levin,CN=Users,DC=onsetinc,DC=com (which is my user) My record on the active directory looks like that: sAMAccountName: itayL distinguishedName: CN=Itay Levin,CN=Users,DC=onsetinc,DC=com memberOf: CN=WaterlooUsers,CN=Users,DC=onsetinc,DC=com and when i get the popup for user/password i enter the username "ItayL" in the authentication message box (and my password) I have 2 questions: How do i configure correctly the roles parameters correctly in the Realm section in the server.xml to enable me to both authenticate and authorize both this group of users WaterlooUsers and also assign them to the appropriate role so that they can see all the relevant pages in my website. - currently it seems that all the Users in my domain are authenticated to the site but get the http-403 Error and can't access any of the pages in the site. I also want to be able to create 2 different set of roles in my site - which can both have access to the same pages - but will see different things on the page. (for instance adding some administrative ability to the admin) Hope it was clear enough and not too long. Thanks in advance, Itay

    Read the article

  • Video Synthesis - Making waves, pattern, gradients...

    - by Nathan
    I'm writing a program to generate some trippy visuals. My code paints each pixel with a random blue value which loops at 0.04 second intervals. for (y = 0; y < 5.5; y += 0.2) { for (x = 0; x < 7.5; x += 0.2) { b = rand() / ((double) RAND_MAX); setPixelColor(x,y,r,g,b); } } I'd like to do more than just make blue noise... but my maths is a bit rusty, and Google isn't helping me much today, so it would be great if you could share anything you know about making waves, patterns, gradient animations, etc or links to such material.

    Read the article

  • What situations does a Monostate pattern model?

    - by devoured elysium
    I know what both a Singleton or a Monostate are and how to implement them. Although I can see many uses for a Singleton, I can't imagine a situation where I would want to let the user create as many instances of my class although in reality only one really exists behind the scenes. Can anybody help me here? I know that for several reasons one should stay away from both patterns, but in theory, what kind of problems does the Monostate model? Thanks

    Read the article

  • Design question what pattern to use

    - by rahul
    Problem Description: We have a requirement of storing the snapshot of an entity temporarily in the database untill a certain period of time untill all the processes to approve the data are completed. Once all approvals are completed the data shall be permanantly persisted into the actual table. Example: 1) Consider an entity called "User". One way to create the user is through the "Create Account Process". 2) The "Create Account Process" shall capture all the information of the User and store it in a temporary table in the database. 3) The data shall be used by the "Account Approval Process" to run its verification process. 4. After all the verification is completed successfully, the User data shall be persisted to the actual table. Question: Where to store the user data entered during "Create Account Process". Additionally, User data should be editable till the verification process is complete.

    Read the article

  • Recursion in Unity and Dispose pattern implementation

    - by Budda
    My class is inherited from UnityContainer (from Unity 2.0), here is source code: public class UnityManager : UnityContainer { private UnityManager() { _context = new MyDataClassesDataContext(); // ... } protected override void Dispose(bool disposing) { if ( disposing ) { _context.Dispose(); } base.Dispose(disposing); } private readonly CMCoreDataClassesDataContext _context; } When Dispose method is called for the instance of UnityManager class it drop into recursion... Why? As far as I know base.Dispose should call the Dispose method of base class only... isn't it? Who call back the Dispose(bool) of UnityManager? How to prevent that? Thanks.

    Read the article

  • Jackson + Builder Pattern?

    - by Gili
    I'd like Jackson to deserialize a class with the following constructor: public Clinic(String name, Address address) Deserializing the first argument is easy. The problem is that Address is defined as: public class Address { private Address(Map<LocationType, String> components) ... public static Builder { public Builder setCity(String value); public Builder setCountry(String value); public Address create(); } } and is constructed like this: new Address.Builder().setCity("foo").setCountry("bar").create(); Is there a way to get key-value pairs from Jackson in order to construct the Address myself? Alternatively, is there a way to get Jackson to use the Builder class itself?

    Read the article

< Previous Page | 33 34 35 36 37 38 39 40 41 42 43 44  | Next Page >