Search Results

Search found 7420 results on 297 pages for 'generic collections'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 42/297 | < Previous Page | 38 39 40 41 42 43 44 45 46 47 48 49  | Next Page >

  • best scala idiom for find & return

    - by IttayD
    This is something I encounter frequently, but I don't know the elegant way of doing. I have a collection of Foo objects. Foo has a method bar() that may return null or a Bar object. I want to scan the collection, calling each object's bar() method and stop on the first one returning an actual reference and return that reference from the scan. Obviously: foos.find(_.bar != null).bar does the trick, but calls #bar twice.

    Read the article

  • Html.Editor() helper in ASP.NET MVC 3 does not work as expected with array in model

    - by SlimShaggy
    In my ASP.NET MVC 3 application I have classes like the following: public class Localization<T> { public int VersionID { get; set; } public T Value { get; set; } ... } public class Localizable<T> { public Localization<T>[] Name { get; set; } ... } Then, I have the following view: @model dynamic ... @for (int i = 0; i < VersionCount; i++) { ... @Html.Editor(string.Format("Name[{0}.Value", i)) ... } Now, when I display this view, passing a subclass of Localizable<string> as the model, the textboxes for the strings are rendered, but they are empty. If I replace @Html.Editor(string.Format("Name[{0}.Value", i)) with @InputExtensions.TextBox(Html, string.Format("Name[{0}].Value", i), Model.Name[i].Value), the textboxes are correctly filled with values from the model. However, using TextBox instead of Editor is not an option for me, because I want to use different editor templates for different types of T. So, what am I doing wrong, or is it a bug in MVC, and is there any workaround?

    Read the article

  • Getting a java collection of objects in Alphabetical order

    - by MichaelMcCabe
    I have a question that I dont really know where to start. So I thought i'd ask it here. Basically, I have a drop down with names in it. I want these names to be in alphabetical order. Populating the drop down happens as follows; I query a database and pull down an Id and Name, make a object called "UserList", and set the name and id variables with what I get back. I then add this object to an ArrayList. I do this over and over. I then convert this collection to an array, and pass it to my JSP page using session.setAttribute("userList", UserList); I then populate the drop down as below. <c:forEach items="${usersCompanysList}" var="c" > There probably is a simple answer but how to I sort these names?

    Read the article

  • How to initialize list with parent child relation

    - by user2917702
    Let's say I have the following classes. public class Parent { public string name; IList<Children> children; } public class Child { public string parentName; public int age; } As it is understandable, each parent can have multiple children, and we can have multiple parents. What is the best way to initialize these classes? Is it better to get all of the parents, and all of the children from database then use LINQ? IList<Parent> parents = GetParents()//assume this gets parents from db IList<Child> children = GetChildren() //assume this gets children from db foreach(Parent parent in parents) { parent.children = children.Where(x=>x.parentName==parent.name).ToList(); } or get all of the parents and iterate through each parent to query database by parentName to get children information? Due to requirement that I have, I cannot use datatable or dataset; I can only use datareader. IList<Parent> parents = GetParents()//assume this gets parents from db foreach(Parent parent in parents) { parent.children = GetChildrenByParentName();//assume this gets parents from db by parentName } Thank you

    Read the article

  • Disable Adding Item to Collection

    - by Wonko the Sane
    Hi All, I'm sure there's an "easy" answer to this, but for the moment it escapes me. In an MVVM application, I have a property that is a ObservableCollection, used for displaying some set of elements on the view. private readonly ObservableCollection<MyType> mMyCollection = new ObservableCollection<MyType>(); public ObservableCollection<MyType> MyCollection { get { return mMyCollection; } } I want to restrict consumers of this collection from simply using the property to add to the collection (i.e. I want to prevent this from the view): viewModel.MyCollection.Add(newThing); // want to prevent this! Instead, I want to force the use of a method to add items, because there may be another thread using that collection, and I don't want to modify the collection while that thread is processing it. public void AddToMyCollection(MyType newItem) { // Do some thread/task stuff here } Thanks, wTs

    Read the article

  • Bind to a collection's view and just call ToString()

    - by womp
    I'm binding a GridView to a collection of objects that look like this: public class Transaction { public string PersonName { get; set; } public DateTime TransactionDate { get; set; } public MoneyCollection TransactedMoney { get; set;} } MoneyCollection simply inherits from ObservableCollection<T>, and is a collection of MyMoney type object. In my GridView, I just want to bind a column to the MoneyCollection's ToString() method. However, binding it directly to the TransactedMoney property makes every entry display the text "(Collection)", and the ToString() method is never called. I understand that it is binding to the collection's default view. So my question is - how can I make it bind to the collection in such a way that it calls the ToString() method on it? This is my first WPF project, so I know this might be a bit noobish, but pointers would be very welcome.

    Read the article

  • List.ForEach method and collection interfaces

    - by tyndall
    In .NET 3.5 List< gains a ForEach method. I notice this does not exist on IList< or IEnumerable< what was the thinking here? Is there another way to do this? Nice and simple short way to do this? I ask because I was at a talk where the speaker said always use the more general interfaces. But why would I use IList< as a return type if I want to be able to turn around and use ForEach? Then I would just end up casting it back to a List<.

    Read the article

  • Java: Efficient Equivalent to Removing while Iterating a Collection

    - by Claudiu
    Hello everyone. We all know you can't do this: for (Object i : l) if (condition(i)) l.remove(i); ConcurrentModificationException etc... this apparently works sometimes, but not always. Here's some specific code: public static void main(String[] args) { Collection<Integer> l = new ArrayList<Integer>(); for (int i=0; i < 10; ++i) { l.add(new Integer(4)); l.add(new Integer(5)); l.add(new Integer(6)); } for (Integer i : l) { if (i.intValue() == 5) l.remove(i); } System.out.println(l); } This, of course, results in: Exception in thread "main" java.util.ConcurrentModificationException ...even though multiple threads aren't doing it... Anyway. What's the best solution to this problem? "Best" here means most time and space efficient (I realize you can't always have both!) I'm also using an arbitrary Collection here, not necessarily an ArrayList, so you can't rely on get.

    Read the article

  • object reference set in java

    - by landon9720
    I need to create a Set of objects. The concern is I do not want to base the hashing or the equality on the objects' hashCode and equals implementation. Instead, I want the hash code and equality to be based only on each object's reference identity (i.e.: the value of the reference pointer). I'm not sure how to do this in Java. The reasoning behind this is my objects do not reliably implement equals or hashCode, and in this case reference identity is good enough.

    Read the article

  • for (Object object : list) [java] construction

    - by EugeneP
    My question, is, whether the sequence of elements picked from a list will always be the same, is this construction behaviour is deterministic for java "List"s - descendants of java.util.List 2) question, if I use for(Object o: list) construction and inside the loop's body increment a variable, will it be the index of list's elements? So, how it goes through list's elements, from 0 to size()-1 or chaotically? List.get(i) will always return this element? 3) question ( I suppose for the 2-nd question the answer will be negative, so:) for (int i=0; i < list.size(); i++) { } is the best way if I need to save the index of an element and later get it back from a list by its id?

    Read the article

  • .NET Garbage Collection behavior (with DataTable)

    - by gmac
    I am wonder why after creating a very simple DataTable and then setting it to null why Garbage Collection does not clear out all the memory used by that DataTable. Here is an example. The variable Before should be equal to Removed but it is not. { long Before = 0, After = 0, Removed = 0, Collected = 0; Before = GC.GetTotalMemory(true); DataTable dt = GetSomeDataTableFromSql(); After = GC.GetTotalMemory(true); dt = null; Removed = GC.GetTotalMemory(true); GC.Collect(); Collected = GC.GetTotalMemory(true); } Gives the following results. Before = 388116 After = 731248 Removed = 530176 Collected = 530176

    Read the article

  • What is the time complexity of LinkedList.getLast() in Java?

    - by i.
    I have a private LinkedList in a Java class & will frequently need to retrieve the last element in the list. The lists need to scale, so I'm trying to decide whether I need to keep a reference to the last element when I make changes (to achieve O(1)) or if the LinkedList class does that already with the getLast() call. What is the big-O cost of LinkedList.getLast() and is it documented? (i.e. can I rely on this answer or should I make no assumptions & cache it even if it's O(1)?)

    Read the article

  • List Question in Java

    - by TiNS
    Hello All, I have a following ArrayList, [Title,Data1,Data2,Data3] [A,2,3,4] [B,3,5,7] And I would like to convert this one like this, [Title,A,B] [Data1,2,3] [Data2,3,5] [Data3,4,7] I'm bit confused with the approach. Any hint would be much appreciated. Thanks.

    Read the article

  • Spring 3 DI using generic DAO interface

    - by Peders
    I'm trying to use @Autowired annotation with my generic Dao interface like this: public interface DaoContainer<E extends DomainObject> { public int numberOfItems(); // Other methods omitted for brevity } I use this interface in my Controller in following fashion: @Configurable public class HelloWorld { @Autowired private DaoContainer<Notification> notificationContainer; @Autowired private DaoContainer<User> userContainer; // Implementation omitted for brevity } I've configured my application context with following configuration <context:spring-configured /> <context:component-scan base-package="com.organization.sample"> <context:exclude-filter expression="org.springframework.stereotype.Controller" type="annotation" /> </context:component-scan> <tx:annotation-driven /> This works only partially, since Spring creates and injects only one instance of my DaoContainer, namely DaoContainer. In other words, if I ask userContainer.numberOfItems(); I get the number of notificationContainer.numberOfItems() I've tried to use strongly typed interfaces to mark the correct implementation like this: public interface NotificationContainer extends DaoContainer<Notification> { } public interface UserContainer extends DaoContainer<User> { } And then used these interfaces like this: @Configurable public class HelloWorld { @Autowired private NotificationContainer notificationContainer; @Autowired private UserContainer userContainer; // Implementation omitted... } Sadly this fails to BeanCreationException: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.organization.sample.dao.NotificationContainer com.organization.sample.HelloWorld.notificationContainer; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [com.organization.sample.NotificationContainer] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)} Now, I'm a little confused how should I proceed or is using multiple Dao's even possible. Any help would be greatly appreciated :)

    Read the article

  • Help me understand these generic method warnings

    - by Raj
    Folks, I have a base class, say: public class BaseType { private String id; ... } and then three subclasses: public class TypeA extends BaseType { ... } public class TypeB extends BaseType { ... } public class TypeC extends BaseType { ... } I have a container class that maintains lists of objects of these types: public class Container { private List<TypeA> aList; private List<TypeB> bList; private List<TypeC> cList; // finder method goes here } And now I want to add a finder method to container that will find an object from one of the lists. The finder method is written as follows: public <T extends BaseType> T find( String id, Class<T> clazz ) { final List<T> collection; if( clazz == TypeA.class ) { collection = (List<T>)aList; } else if( clazz == TypeB.class ) { collection = (List<T>)bList; } else if( clazz == TypeC.class ) { collection = (List<T>)cList; } else return null; for( final BaseType value : collection ) { if( value.getId().equals( id ) ) { return (T)value; } } return null; } My question is this: If I don't add all the casts to T in my finder above, I get compile errors. I think the compile should be able to infer the types based on parametrization of the generic method (). Can anyone explain this? Thanks. -Raj

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 38 39 40 41 42 43 44 45 46 47 48 49  | Next Page >