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  • Method in ICollection in C# that adds all elements of another ICollection to it

    - by drasto
    Is there some method in ICollection in C# that would add all elements of another collection? Right now I have to always write foreach cycle for this: ICollection<Letter> allLetters = ... //some initalization ICollection<Letter> justWrittenLetters = ... //some initalization ... //some code, adding to elements to those ICollections foreach(Letter newLetter in justWrittenLetters){ allLetters.add(newLetter); } My question is, is there method that can replace that cycle? Like for example the method addAll(Collection c) in Java ? So I would write only something like: allLetters.addAll(justWrittenLetters);

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  • lift `??` construct and maven example

    - by coubeatczech
    Hi, I have browsed lift's MegaProtoUser and encountered this construction: ??("Last Name"). Can anyone explain, what that means? Also, I didn't find a way how to add a custom field into MegaProtoUser. The maven's lift's basic archetype defines another field, but it never shows anywhere. (Version 1.0) Thanks for answering

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  • What is the big deal with IQueryable?

    - by jjr2527
    I've seen a lot of people talking about IQueryable and I haven't quite picked up on what all the buzz is about. I always work with generic List's and find they are very rich in the way you can "query" them and work with them, even run LINQ queries against them. So I'm wondering if there is a good reason to start considering a different default collection in my projects.

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  • How to traverse the item in the collection in a List or Observable collection?

    - by Ashish Ashu
    I have a collection that is binded to my Listview. I have provided options to user to "move up" "move down" the selected item in the list view. I have binded the selected item of the listview to my viewmodel, hence I get the item in the collection on which user want to do the operation. I have attached "move up" "move down" commands in my viewmodel. I want what is the best way to move up and down in the collection in the collection which is reflected in the list view. Please suggest.

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  • deploying gwt web application on jetty

    - by Azhar
    Hi I am deploying my web application created in Gwt on the jetty. I have used mongodb as my database.After starting the server it starts deploying the weapp.war and gives following error - 694 [main] INFO org.mortbay.log - Extract /usr/share/jetty/webapps/myapp.war to /tmp/Jetty_0_0_0_0_8090_myapp.war__myapp__n6yltk/webapp 3567 [main] WARN org.mortbay.log - failed Startup: java.lang.LinkageError: loader constraint violation: loader (instance of org/mortbay/jetty/webapp/WebAppClassLoader) previously initiated loading for a different type with name "javax/management/MBeanServer" at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:634) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:277) at java.net.URLClassLoader.access$000(URLClassLoader.java:73) at java.net.URLClassLoader$1.run(URLClassLoader.java:212) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:205) at org.mortbay.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:392) at org.mortbay.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:363) at com.mongodb.DBPortPool$Holder.get(DBPortPool.java:58) at com.mongodb.DBTCPConnector._set(DBTCPConnector.java:458) at com.mongodb.DBTCPConnector.<init>(DBTCPConnector.java:46) at com.mongodb.Mongo.<init>(Mongo.java:137) at com.mongodb.Mongo.<init>(Mongo.java:123)

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  • By-Name-Parameters for Constructors

    - by hotzen
    Hello, coming from my other question is there a way to get by-name-parameters for constructors working? I need a way to provide a code-block which is executed on-demand/lazy/by-name inside an object and this code-block must be able to access the class-methods as if the code-block were part of the class. Following Testcase fails: package test class ByNameCons(code: => Unit) { def exec() = { println("pre-code") code println("post-code") } def meth() = println("method") def exec2(code2: => Unit) = { println("pre-code") code2 println("post-code") } } object ByNameCons { def main(args: Array[String]): Unit = { val tst = new ByNameCons { println("foo") meth() // knows meth() as code is part of ByNameCons } tst.exec() // ByName fails (executed right as constructor) println("--------") tst.exec2 { // ByName works println("foo") //meth() // does not know meth() as code is NOT part of ByNameCons } } } Output: foo method pre-code post-code -------- pre-code foo post-code

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  • Remove Duplicates from List of HashMap Entries

    - by HonorGod
    I have a List<HashMap<String,Object>> which represents a database where each list record is a database row. I have 10 columns in my database. There are several rows where the values of 2 particular columns are equals. I need to remove the duplicates from the list after the list is updated with all the rows from database. What is the efficient way? FYI - I am not able to do distinct while querying the database, because the GroupName is added at a later stage to the Map after the database is loaded. And since Id column is not primary key, once you add GroupName to the Map. You will have duplicates based on Id + GroupName combination! Hope my question makes sense. Let me know if we need more clarification.

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  • IList<Item> Collection Class accessing database

    - by Mike
    Hi, I have a database with Users. Users have Items. These Items can change actively. How do you access the items in a collection type format? For the user, I fill all the user properties at the time of instantiation. If I load the user's items at the time of the instantiation, and the items change, they will have old data. I was thinking, maybe I need an ItemCollection class and have that a field/property apart of the user class, that way to traverse all the user's items I could use a foreach loop. So, my question is, what is the best practice/best way of accessing the items from a database using some sort of collection? On accessing the particular Item, it needs to get the latest database information, and when the user does do a foreach loop, the latest item information must be available. I.e. What I'm trying to do Console.WriteLine(User.Items[3].ID); returns 5. //this updates the item information and saves it to the database. User.Items[3].ID = 13; //Add a new item to the database. User.Items.Add(new Item { id = 17}); foreach (Item item in User.Items) { //this would traverse all items in the database. //not some cached copy at the time of instantiation of the user. }

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  • remove specific values from multi value dictionary

    - by Anthony
    I've seen posts here on how to make a dictionary that has multiple values per key, like one of the solutions presented in this link: Multi Value Dictionary it seems that I have to use a List< as the value for the keys, so that a key can store multiple values. the solution in the link is fine if you want to add values. But my problem now is how to remove specific values from a single key. I have this code for adding values to a dictionary: private Dictionary<TKey, List<TValue>> mEventDict; // this is for initializing the dictionary public void Subscribe(eVtEvtId inEvent, VtEvtDelegate inCallbackMethod) { if (mEventDict.ContainsKey(inEvent)) { mEventDict[inEvent].Add(inCallbackMethod); } else { mEventDict.Add(inEvent, new List<TValue>() { v }); } } // this is for adding values to the dictionary. // if the "key" (inEvent) is not yet present in the dictionary, // the key will be added first before the value my problem now is removing a specific value from a key. I have this code: public void Unsubscribe(eVtEvtId inEvent, VtEvtDelegate inCallbackMethod) { try { mEventDict[inEvent].Remove(inCallbackMethod); } catch (ArgumentNullException) { MessageBox.Show("The event is not yet present in the dictionary"); } } basically, what I did is just replace the Add() with Remove() . Will this work? Also, if you have any problems or questions with the code (initialization, etc.), feel free to ask. Thanks for the advice.

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  • jquery-sortable using behavior of a linkedlist

    - by BabaBooey
    I suspect I'm not looking at this issue in the right way so here goes. I have essentially a LinkedList of data on a web page (http://en.wikipedia.org/wiki/Linked_list) that I'd like to manipulate using traditional Linked List behavior (i.e. just updating the reference/id of the "next" object) for performance reasons. Where this gets a bit tricky is I'd ideally like to use Jquery's sortable to do this. Like the user would drag something up/down and I could just do an Ajax call to the server with the id of the object that moved and the new parent id of that object (and then behind the scenes I could figure out how to reconnect things..maybe need more data than that...). But every example I've seen where sortable is used they were sending the whole re-indexed list to the database to update which seems unnecessary to me. With a linked list to change an element's "index" I only need to make 3 updates which depending on the size of the list could be a big performance savings. Anyone have an example of what I'm trying to do...am I too far in left field?

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  • How do I get the scalaz IDEA live templates working for the symbolic methods?

    - by oxbow_lakes
    Many of the methods in scalaz have symbolic equivalents, such as forever and 8 (of course, I have this the wrong way round, the symbolic methods really have ASCII equivalents). The project contains a live templates XML file for IDEA so these can be auto-completed, I believe by using the forever+TAB shortcut (in the above instance). I can't figure out how to import this live template into IDEA and actually use it, though. How can I do that?

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  • Building resultset using collection object

    - by Bhaskara Krishna Mohan Potam
    Hi, I had an issue in building the resultset using java. Here it goes... I am storing a collection object which is organized as row wise taken from a resultset object and putting the collection object(which is stored as vector/array list) in cache and trying to retrieve the same collection object. Here i need to build back the resultset again using the collection object. Now my doubt is building the resultset in this way possible or not? Please let me know asap. Thanks in advance, Bhaskar

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  • C# Get Type of IEnumerable<TModel>

    - by Jimbo
    I have a method to which I pass an IEnumerable<TModel>. Then depending on the type of TModel, the method carries out a set of instructions as below: public void MyMethod<TModel>(IEnumerable<TModel> items) where TModel : class { int operationType; switch (typeof(TModel)) { case typeof(MyModelOne): operationType = 1; break; case typeof(MyModelTwo): operationType = 2; break; case typeof(MyModelThree): operationType = 3; break; default: throw new Exception("The collection model passed to MyMethod is not recognized"); } ... } This doesnt work, I get the error: There is no application variable or memeber 'TModel'

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  • How to work threading with ConcurrentQueue<T>.

    - by dboarman
    I am trying to figure out what the best way of working with a queue will be. I have a process that returns a DataTable. Each DataTable, in turn, is merged with the previous DataTable. There is one problem, too many records to hold until the final BulkCopy (OutOfMemory). So, I have determined that I should process each incoming DataTable immediately. Thinking about the ConcurrentQueue<T>...but I don't see how the WriteQueuedData() method would know to dequeue a table and write it to the database. For instance: public class TableTransporter { private ConcurrentQueue<DataTable> tableQueue = new ConcurrentQueue<DataTable>(); public TableTransporter() { tableQueue.OnItemQueued += new EventHandler(WriteQueuedData); // no events available } public void ExtractData() { DataTable table; // perform data extraction tableQueue.Enqueue(table); } private void WriteQueuedData(object sender, EventArgs e) { BulkCopy(e.Table); } } My first question is, aside from the fact that I don't actually have any events to subscribe to, if I call ExtractData() asynchronously will this be all that I need? Second, is there something I'm missing about the way ConcurrentQueue<T> functions and needing some form of trigger to work asynchronously with the queued objects?

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  • Testing SocketChannel NIO

    - by hotzen
    Hello, I just wrote some NIO-code and wonder how to stress-test my implementation regarding SocketChannel.write(ByteBuffer) not able to write the whole byte-buffer SocketChannel.read(ByteBuffer) reading the data in chunks into ByteBuffer are there some simple linux-utilities like telnet to open a ServerSocket with some buffering-options?

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  • How to compare two maps by their values

    - by lewap
    How to compare two maps by their values? I have two maps containing equal values and want to compare them by their values. Here is an example: Map a = new HashMap(); a.put("f"+"oo", "bar"+"bar"); a.put("fo"+"o", "bar"+"bar"); Map b = new HashMap(); a.put("f"+"oo", "bar"+"bar"); a.put("fo"+"o", "bar"+"bar"); System.out.println("equals: " + a.equals(b)); // obviously false .... what to call to obtain a true? Obviously, to implement a comparison it not difficult, it is enough to compare all keys and their associated values. I don't believe I'm the first one to do this, so there must be already a library functions either in java or in one of the jakarta.commons libraries. Thanks

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  • Special kind of queue

    - by devoured elysium
    I am looking for something like a Queue that would allow me to put elements at the end of the queue and pop them out in the beggining, like a regular Queue does. The difference would be that I also need to compact the Queue from time to time. This is, let's assume I have the following items on my Queue (each character, including the dot, is an item in the Queue): e d . c . b . a (this Queue has 8 items) Then, I'd need for example to remove the last dot, so to get: e d . c . b a Is there anything like that in the Java Collection classes? I need to use this for a program I am doing where I can't use anything but Java's classes. I am not allowed to design one for myself. Currently I'm just using a LinkedList, but I thought maybe this would be more like a Queue than a LinkedList. Thanks

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  • Lift XML Parsing Error

    - by bstevens90
    I know there are other questions on this and I have read through almost all of them and none of them solved my problem. I have inside a home directory: def search(in: NodeSeq) : NodeSeq = { bind("work", in, "docId" -> text("", did = _), "visitId" -> text("", vid = _), "provider" -> text("", prov = _), "emCode" -> text(ecode, ecode = _)) } along with: <lift:home.searchForm form="POST" multipart="true" > <table> <tr> <td>DocId</td> <td>VisitId</td> <td>Provider</td> <td>EanMCode</td> </tr> <tr> <td><work:docId /></td> <td><work:visitId /></td> <td><work:provider /></td> <td><work:emCode /></td> <td><button>Click Me!</button></td> </tr> </table> </lift:home.searchForm> Inside an html page. I have included xmlns:lift="http://liftweb.net/" in default.... I can't find anyway to fix this... I am getting XML Parsing Error: prefix not bound to a namespace Location: http://localhost:8080/ Line Number 29, Column 10: <td><work:docId></work:docId></td> in firefox. I have written similar code and had it working in another app and just cant even find anything im doing different thats not trivial naming... Thanks in advance!

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  • How to count occurrence of an element in a List

    - by MM
    I have an ArrayList a collection class of java as follows. ArrayList<String>animals = new ArrayList<String>(); animals.add("bat"); animals.add("owl"); animals.add("bat"); animals.add("bat"); As you can see the animals ArrayList consists of 3 bat elements and one owl element. I was wondering if there is any API in collection framework that returns the number of bat occurrences or is there a way to determine number of occurrences. I found that google's collection multiset does have an api that returns total number of occurrences of an element. But that is compatible only with jdk1.5. Our product is currently in jdk 1.6. Hence cannot use it.

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  • What causes this retainAll exception?

    - by Joren
    java.lang.UnsupportedOperationException: This operation is not supported on Query Results at org.datanucleus.store.query.AbstractQueryResult.contains(AbstractQueryResult.java:250) at java.util.AbstractCollection.retainAll(AbstractCollection.java:369) at namespace.MyServlet.doGet(MyServlet.java:101) I'm attempting to take one list I retrieved from a datastore query, and keep only the results which are also in a list I retrieved from a list of keys. Both my lists are populated as expected, but I can't seem to user retainAll on either one of them. // List<Data> listOne = new ArrayList(query.execute(theQuery)); // DatastoreService ds = DatastoreServiceFactory.getDatastoreService(); // List<Data> listTwo = new ArrayList(ds.get(keys).values()); // listOne.retainAll(listTwo);

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  • trait implementation

    - by Jeriho
    If I have some traits like: trait A {...} trait B extends A{...} trait C1 extends B{...} trait C2 extends A{...} I can write class in two ways (C1 and C2 add same functionality) class Concrete1 extends B with C1 class Concrete2 extends B with C2 What variant is better(efficient)?

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  • WPF: change DataTemples according to Value

    - by Kave
    I have a class called Cell with two properties. One is called Value of type int? And the other is called Candidates of type ObservableCollection during the initialization I am utilizing a DataTemplateSelector to choose between two datatemplates for two different scenarios. If the Value property has a value then template A should be used to present the Cell class. However if the Value property is null Then template B should be used to present the Cell class. While this works perfectly fine during the initialization however during the runtime the templates don't change any more when the value of the Value property actually changes. Is the approach of using DataTemplateSelector the wrong approach to change DataTemplates dynamically? What would you recommend I should do? Many thanks,

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