collections

问题 I am trying to make a dynamic Web Service in which i will be expecting a Java hash map or an Array list for the argument. I am using the following code in Class Code: package demo; import java.util.ArrayList; import javax.jws.WebService; @WebService public class HashMapTest { public HashMapTest() { super(); } public int getResponse(ArrayList<String> hm) { return hm.size(); } } I am using an IDE: Oracle Jdeveloper 11g. when i use the Wizard in the same, the output WSDL is as given below: <?xml

问题 What is the best way to store between a million to 450,000 Boolean values in a dictionary like collection indexed by a long number? I need to use the least amount of memory possible. True and Int both take up more than 22 bytes per entry. Is there a lower memory per Boolean possible? 回答1: Check this question. Bitarray seems to be the preferred choice. 回答2: The two main modules for this are bitarray and bitstring (I wrote the latter). Each will do what you need, but some plus and minus points

问题 This question already has answers here : Iterating through a Collection, avoiding ConcurrentModificationException when removing objects in a loop (24 answers) Closed 11 months ago . why following code throwing ConcurrentModificationException? Josh Bloch can avoid ConcurrentModificationException. ArrayList<Integer> list=new ArrayList<Integer>(); list.add(100); list.add(200); list.add(300); list.add(400); for(Integer field : list) { list.remove(field); list.add(200); } 回答1: You can't use remove

问题 I have this simple function to add a Folder to a collection called 'Folders'. folderAdded: function(folder) { this.folders.add(folder); this.$el.empty(); this.render(); } By default this will add the object in the first position, so it will appear the first one. As my query is order by created, if I refresh the page, the object will go the first place. How can I add the object at the beginning of the collection ? 回答1: You can use unshift method of the collection. Add a model at the beginning

问题 Bottom Line Up Front Is there a succinct way that I can constrain the number of child entities that can belong to a parent in Entity Framework. I am using 4.3.1 at the moment. The Problem I am developing an ASP.NET MVC3 site which accesses data via a data access layer that uses Entity Framework. I have a SearchList entity which has a many to many relationship to a Search entity. A SearchList may have many Searches, and a Search may belong to many SearchLists. At one point in the workflow of

问题 I have this Player class which implements the Comparable interface. Then I have an ArrayList of Player s. I'm trying to use binarySearch() on the list of Player s to find one Player , but Java is giving me a " cannot find symbol: method binarySearch(java.util.ArrayList< Player>,Player) ". This the Player class: class Player implements Comparable { private String username; private String password; Statistics stats; //Constructor, creates a new Player with a supplied username Player(String name

问题 I have an ArrayList which having many objects. I want to do sum of values of the same property name. Examples Data in Array List which is Objects of ProfitAndLossDataDO "Michel" , 5000 "Alex" , 5000 "Edvin" , 4000 "Sosha" , 3000 "Michel" , 2000 "Alex" , 3000 And the Result Would be (Sum of values when person are same)- "Michel" ,7000 "Alex" , 8000 "Edvin" , 4000 "Sosha" , 3000 The Logic class ProfitAndLossDataDO public class ProfitAndLossDataDO { String ledgerName; double ledgerAmount; public

问题 I've been a Java programmer almost exclusively for the past 8 years or so, and recently I've been playing with C++ again. Here's an issue that I've come up against with regards to iterators in C++ STL and Java. In Java, you can write a method that takes an iterator like this: void someMethod(Iterator<String> data) { // ... } You pass in an Iterator and the method does not need to know what the underlying collection of that iterator is, which is good. In C++, there is no common base class for

问题 I have a C# .NET 3.5 project that unfortunately relies on a couple of VB6 ActiveX controls. Up until now I have been able to happily access the data containers and methods defined in the ActiveX controls by simply adding a reference to the controls in my project and referencing them as normal. However I hit a snag today when I had to call a method that returns a VBA.Collection. My code will compile with no problem, but at runtime I get the following error: Could not load file or assembly

问题 Suppose I have an ICollection<SomeClass> . I have the following two variables: SomeClass old; SomeClass new; How can I achieve something like the following using an ICollection<SomeClass> ? // old is guaranteed to be inside collection collection.Replace(old, new); 回答1: There is no black magic here: ICollection<T> is not ordered and only provides Add / Remove methods. Your only solution would be to check if the actual implementation is something more , such as IList<T> : public static void