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  • Android Maven and Refresh Problem

    - by antonio Musella
    Hi all, i've a strange problem with maven and android I've 3 maven project and 2 normal java maven project divided in this manner : normal project : model project ... packaged as jar ... contains java Pojo Bean and Interface. Dao Project ... packaged as jar ... contains Db Logic - Depend on model Project Android Application Maven project ContentProvider ... packaged as apk ... contains ContentProviders only. Depends on Dao Project Editors ... packaged as apk ... contains only Editor, Depends on Dao project MainApp ... packaged as apk ... contains MyApp, Depends on DAO ... The Problem is that if i modify DAO Project , Then do a maven clean and maven install of all apk project, then run as Android Application within Eclipse, i don't see updated app on my Emulator. Nicely if i shut down my ubuntu workstation and restart it i can see The updated app on my Emulator. Do you know a solution for this issue ? thanks and regards

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  • What is an efficient strategy for multiple threads posting jobs and waiting for response from a single thread?

    - by jakewins
    In java, what is an efficient solution to the following problem: I have multiple threads (10-20 or so) generating jobs ("Job Creators"), and a single thread capable of performing them ("The worker"). Once a job creator has posted a job, it should wait for the job to finish, yielding no result other than "it's done", before it keeps going. For sending the jobs to the worker thread, I think a ring buffer or similar standard fan-in setup would perhaps be a good approach? But for a Job Creator to find out that her job has been done, I'm not so sure.. The job creators could sleep, and the worker interrupt them when done.. Or each job creator could have an atomic boolean that it checks, and that the worker sets. I dunno, neither of those feel very nice. I'd like to do it with as few (none, if possible) locks as absolutely possible. So to be clear: What I'm looking for is speed, not necessarily simplicity. Does anyone have any suggestions? Links to reading about concurrency strategies would also be very welcome!

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  • How can I intercept an exception occurred during serialization in WCF?

    - by bonomo
    I have a legit data object with all data contract / data member attributes. For some reason the WCF service crashes after the operation has completed and the result is passed as a return value. I believe it has something to do with WCF not being able to serialize that result properly. The test client doesn't say anything specific: The underlying connection was closed: The connection was closed unexpectedly. Server stack trace: at System.ServiceModel.Channels.HttpChannelUtilities.ProcessGetResponseWebException(WebException webException, HttpWebRequest request, HttpAbortReason abortReason) at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout) at System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan timeout) at System.ServiceModel.Dispatcher.RequestChannelBinder.Request(Message message, TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation) at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message) Exception rethrown at [0]: at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) at IFacade.PickSecurities(String pattern, Int32 atMost) at FacadeClient.PickSecurities(String pattern, Int32 atMost) Inner Exception: The underlying connection was closed: The connection was closed unexpectedly. at System.Net.HttpWebRequest.GetResponse() at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout) I am in control of creating the instance of the service using a customized service host factory. I know I can set up trace listeners and check the logs, but it's a lot of hassle to do. So I would rather handle it explicitly on the server at the time it happens. So I how can I intercept that exception programmatically and return an appropriate fault meassage?

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  • Pointers, am I doing them correctly? Objective-c/cocoa

    - by Chris
    I have this in my @interface struct track currentTrack; struct track previousTrack; int anInt; Since these are not objects, I do not have to have them like int* anInt right? And if setting non-object values like ints, boolean, etc, I do not have to release the old value right (assuming non-GC environment)? The struct contains objects: typedef struct track { NSString* theId; NSString* title; } *track; Am I doing that correctly? Lastly, I access the struct like this: [currentTrack.title ...]; currentTrack.theId = @"asdf"; //LINE 1 I'm also manually managing the memory (from a setter) for the struct like this: [currentTrack.title autorelease]; currentTrack.title = [newTitle retain]; If I'm understanding the garbage collection correctly, I should be able to ditch that and just set it like LINE 1 (above)? Also with garbage collection, I don't need a dealloc method right? If I use garbage collection does this mean it only runs on OS 10.5+? And any other thing I should know before I switch to garbage collected code? Sorry there are so many questions. Very new to objective-c and desktop programming. Thanks

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  • How to (unit-)test data intensive PL/SQL application

    - by doom2.wad
    Our team is willing to unit-test a new code written under a running project extending an existing huge Oracle system. The system is written solely in PL/SQL, consists of thousands of tables, hundreds of stored procedures packages, mostly getting data from tables and/or inserting/updating other data. Our extension is not an exception. Most functions return data from a quite complex SELECT statementa over many mutually bound tables (with a little added logic before returning them) or make transformation from one complicated data structure to another (complicated in another way). What is the best approach to unit-test such code? There are no unit tests for existing code base. To make things worse, only packages, triggers and views are source-controlled, table structures (including "alter table" stuff and necessary data transformations are deployed via channel other than version control). There is no way to change this within our project's scope. Maintaining testing data set seems to be impossible since there is new code deployed to the production environment on weekly basis, usually without prior notice, often changing data structure (add a column here, remove one there). I'd be glad for any suggestion or reference to help us. Some team members tend to be tired by figuring out how to even start for our experience with unit-testing does not cover PL/SQL data intensive legacy systems (only those "from-the-book" greenfield Java projects).

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  • Flexible forms and supporting database structure

    - by sunwukung
    I have been tasked with creating an application that allows administrators to alter the content of the user input form (i.e. add arbitrary fields) - the contents of which get stored in a database. Think Modx/Wordpress/Expression Engine template variables. The approach I've been looking at is implementing concrete tables where the specification is consistent (i.e. user profiles, user content etc) and some generic field data tables (i.e. text, boolean) to store non-specific values. Forms (and model fields) would be generated by first querying the tables and retrieving the relevant columns - although I've yet to think about how I would setup validation. I've taken a look at this problem, and it seems to be indicating an EAV type approach - which, from my brief research - looks like it could be a greater burden than the blessings it's flexibility would bring. I've read a couple of posts here, however, which suggest this is a dangerous route: How to design a generic database whose layout may change over time? Dynamic Database Schema I'd appreciate some advice on this matter if anyone has some to give regards SWK

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  • Maven: Repository no longer exists! Now what?

    - by pek
    I have just begun my journey in Maven2 and found the dependency repositories logic a little weird... As far as I understand, I need to point Maven to a repository from which it can fetch the various POMs found in my dependencies. In other words, instead of downloading all the dependencies in my lib folder, as I did in the Ant era, I now have to look into various Maven repositories and, hopefully, find what I need. OK, thanks to MVNBrowser things get a little easier. But! What if the Maven repository no longer exists? For example, I use Slick in my project. Among the other dependencies, slick uses JNLP (for some reason). The artifact for jnlp is: <dependency> <groupId>javax.jnlp</groupId> <artifactId>jnlp</artifactId> <version>1.2</version> </dependency> According to MVNBrowser, javax.jnlp can only be found in one repository, Freehep. Which is no longer available. So now what?

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  • Skipping the BufferedReader readLine() method in java

    - by DDP
    Is there a easy way to skip the readLine() method in java if it takes longer than, say, 2 seconds? Here's the context in which I'm asking this question: public void run() { boolean looping = true; while(looping) { for(int x = 0; x<clientList.size(); x++) { try { Comm s = clientList.get(x); String str = s.recieve(); // code that does something based on the string in the line above } // other stuff like catch methods } } } Comm is a class I wrote, and the receive method, which contains a BufferedReader called "in", is this: public String recieve() { try { if(active) return in.readLine(); } catch(Exception e) { System.out.println("Comm Error 2: "+e); } return ""; } I've noticed that the program stops and waits for the input stream to have something to read before continuing. Which is bad, because I need the program to keep looping (as it loops, it goes to all the other clients and asks for input). Is there a way to skip the readLine() process if there's nothing to read? I'm also pretty sure that I'm not explaining this well, so please ask me questions if I'm being confusing.

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  • android: consume key press, bypassing framework processing

    - by user360024
    What I want android to do: when user presses a single key, have the view respond, but do so without opening a text area and displaying the character associated with the key that was pressed, and without requiring that the Enter key be pressed, and without requiring that the user press Esc to make the text area go away. For example, when user presses "u" (and doesn't press Enter), that means "undo the last action", so the controller and model immediately undo the last action, then the view does an invalidate() and user sees that their last action has been undone. In other words the "u" key press should be silently processed, such that the only visual result is that user's last action has been undone. I've implemented OnKeyListener and provided an onKey() method: the class: public class MyGameView extends View implements OnKeyListener{ in the constructor: //2010jun06, phj: With onKey(), helps let this View consume key presses // before the framework gets a chance to consume the key press. setOnKeyListener((View.OnKeyListener)this); the onKey() method: public boolean onKey(View v, int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_R) { Log.d("BWA", "In onKey received keycode associated with R."); } return true; // meaning the event (key press) has been consumed, so // the framework should not handle this event. } but when user presses "u" key on the emulator keypad, a textarea is opened at the bottom of the screen, the "u" charater is displayed there, and the onKey() method doesn't execute until user presses the Enter key. Is there a way to make android do what I want? Thanks,

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  • Serialized NHibernate Configuration objects - detect out of date or rebuild on demand?

    - by fostandy
    I've been using serialized nhibernate configuration objects (also discussed here and here) to speed up my application startup from about 8s to 1s. I also use fluent-nhibernate, so the path is more like ClassMap class definitions in code fluentconfiguration xml nhibernate configuration configuration serialized to disk. The problem from doing this is that one runs the risk of out of date mappings - if I change the mappings but forget to rebuild the serialized configuration, then I end up using the old mappings without realising it. This does not always result in an immediate and obvious error during testing, and several times the misbehaviour has been a real pain to detect and fix. Does anybody have any idea how I would be able to detect if my classmaps have changed, so that I could either issue an immediate warning/error or rebuild it on demand? At the moment I am comparing timestamps on my compiled assembly against the serialized configuration. This will pickup mapping changes, but unfortunately it generates a massive false positive rate as ANY change to the code results in an out of date flag. I can't move the classmaps to another assembly as they are tightly integrated into the business logic. This has been niggling me for a while so I was wondering if anybody had any suggestions?

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  • Intermittent Issue Writing to Google Appengine Datastore

    - by user242153
    Hi, I have a functioning app and recently have had intermittent problems writing to the datastore. I did not make any relevant code changes, however in the last few days my attempts to write to the datastore sometimes work and sometimes don't. I am trying to save an object that is in a many to one relationship with an existing persisted parent. So, the logic works like this: 1) Parent pulled from the datastore 2) Child created / instantiated using constructor 3) Parent.addSingleChild(child); // the "addSingleChild" method just adds the object argument to the collection of children 4) child.setParent(Parent); // sets the Parent object to the parent field I am using transactions as explained in the documentation ending with "finally {if (tx.isActive()) {tx.rollback(); } }" When the servlet is called, the parent is called from the datastore and the child object is created and added to the many to one mapping to the pre-existing parent. The child should automatically be persisted, since the parent is already persistent, and the child is added to the collection of children that map to the parent. And it worked this way in the past. However, to be sure, i did add a pm.makePersistent(child). Doesn't seem to help, still have the intermittent problem. Any suggestions would be appreciated, and if you need to see the actual code I can post. Thanks

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  • Is there a better way to write this LINQ query?

    - by Raj Aththanayake
    Hi Is there a better simplified way to write this query. My logic is if collection contains customer ids and countrycodes, do the query ordey by customer id ascending. If there are no contain id in CustIDs then do the order by customer name. Is there a better way to write this query? I'm not really familiar with complex lambdas. var custIdResult = (from Customer c in CustomerCollection where (c.CustomerID.ToLower().Contains(param.ToLower()) && (countryCodeFilters.Any(item => item.Equals(c.CountryCode))) ) select c).ToList(); if (custIdResult.Count > 0) { return from Customer c in custIdResult where ( c.CustomerName.ToLower().Contains(param.ToLower()) && countryCodeFilters.Any(item => item.Equals(c.CountryCode))) orderby c.CustomerID ascending select c; } else { return from Customer c in CustomerCollection where (c.CustomerName.ToLower().Contains(param.ToLower()) && countryCodeFilters.Any(item => item.Equals(c.CountryCode))) orderby c.CustomerName descending select c; }

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  • Linked List push()

    - by JKid314159
    The stack is initialized with a int MaxSize =3. Then I push one int onto the list. " Pushed:" is returned to the console. Program crashes here. I think my logic is flawed but unsure. Maybe an infinite loop or unmet condition? Thanks for your help. I'm trying to traverse the list to the last node in the second part of the full() method. I implemented this stack as array based so must implement this method full() as this method is inside of main class. while(!stacker.full()) { cout << "Enter number = "; cin >> intIn; stacker.push(intIn); cout << "Pushed: " << intIn << endl; }//while Call to LinkListStack.cpp to class LinkList full(). int LinkList::full() { if(head == NULL) { top = 0; } else { LinkNode * tmp1; LinkNode * tmp2; tmp1 = head; while(top != MaxSize) { if(tmp1->next != NULL){ tmp2 = tmp1->next; tmp1 = tmp2; ++top; }//if }//while }//else return (top + 1 == MaxSize); }

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  • Semantically correct nested anchors

    - by Blackie123
    I am working on a web applicaton. And what we also create is something that could be described as inline editing. Just to portray thing I am trying to solve I use example of Facebook post. You have post like. Steve Jobs added 5 new photos Steve Jobs is link that redirects to his profile so in HTML, that would be: <div class="post-block"> <p><a href="stevejobs/" title="#">Steve Jobs</a> added 5 new photos.<p> </div> But what I want is the whole post "block" to be clickable although I want only that name to appear to be link. Normally in HTML logic would say to to this: <a href="stevejobs/" title="#"><div class="post-block"> <p><a href="stevejobs/" title="#">Steve Jobs</a> added 5 new photos.<p> </div></a> But this isn't semantically correct. Quick look to HTML 4.01 or any other standard says something like this: Links and anchors defined by the A element must not be nested; an A element must not contain any other A elements. How to create it semantically correct other than using javascript and defining div:hover state for the whole "div anchor"?

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  • How to embed a precharged collection of non-entity forms in symfony2

    - by metalvarez
    I want to embed a collection of precharged non-entity forms, here is the code, first is the parent form buildForm method. public function buildForm(FormBuilderInterface $builder, array $options) { $builder->add("example1")->add("example2"); $builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event) { /*some logic to do before adding the collection of forms*/ $form->add('aclAccess', 'collection', array( 'type' => new ChildFormType(), 'allow_add' => true, 'mapped' => false, 'data' => /* I dont know how to precharge a collection of non-entity forms*/ )); }); } now the child form public function buildForm (FormBuilderInterface $builder, array $options) { $builder->add("test1", "text", array("read_only" => true, "data" => "test")); $builder->->add("test2", "choice", array( 'choices' => array('opt1' => 'Opt1', 'opt2' => 'Opt2'), 'multiple' => true, 'expanded' => true )); } so basicly i want to manage those child options in the test2 field as separated forms, each option group will depend on the value of the test1 field, i know this can be done by coding everythin in twig without form classes but i think having form classes its the best practice to run phpunit test, for maintainability, etc ...

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  • Bulletin board - Database optimisation

    - by andrew
    This question is a follow on from this Question The project and problem The project I am currently working on is a bulletin board for a large non-profit organisation. The bulletin board will be used to allow inter-office communication within the organisation. I am building the application and have been having trouble extracting the results that I need from my database because I don't think it is properly normalized and because of limitations in my knowledge of relational database theory and mysql. I would appreciate input into the design of the board in general and in particular, ways that the database structure can be improved to facilitate efficient queries and help me develop this application and future application faster Business Logic The bulletin board will be used in the following way Posting bulletins and responses to bulletins Employees or 'users' in offices around the country will be able to post messages to the bulletin board.Bulletins must be posted to a location and categorised- i'll call these "bulletins". Users will be able to post any number of replies to any one bulletin and users will be able to reply to their own bulletin - i'll call these 'replies'. Rating bulletins and replies Users will be able to either 'like' or 'dislike' a bulletin or a reply and the total number of likes or dislikes will be shown for each bulletin or reply. Viewing the bulletin board and responses Bulletins can be displayed chronologically. Users can sort bulletins chronologically or chronologically by the latest reply to that bulletin(let me know if you need more explanation) When a particular bulletin is selected, replies to that bulletin will be displayed chronologically @PerformanceDBA - edited 10:34 est 28/12/10I have begun implementing the data model. I assume that the 6th data model is the physical model because it contains the associative tables. I am going to post any questions that I have below. I will put up a database dump once I am done. I will then put up a list of all the queries that I need to run on the database and begin writing them. I hope you had a good Christmas. I'm in Canada and there's snow! Implementation of Physical model

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  • List local printers

    - by vladimir
    hi all, i am using this routine to list the local printers installed on on a machine... var p: pointer; hpi: _PRINTER_INFO_2A; hGlobal: cardinal; dwNeeded, dwReturned: DWORD; bFlag: boolean; i: dword; begin p := nil; EnumPrinters(PRINTER_ENUM_LOCAL, nil, 2, p, 0, dwNeeded, dwReturned); if (dwNeeded = 0) then exit; GetMem(p,dwNeeded); if (p = nil) then exit; bFlag := EnumPrinters(PRINTER_ENUM_LOCAL, nil, 2, p, dwneeded, dwNeeded, dwReturned); if (not bFlag) then exit; CbLblPrinterPath.Properties.Items.Clear; for i := 0 to dwReturned - 1 do begin CbLblPrinterPath.Properties.Items.Add(TPrinterInfos(p^)[i].pPrinterName); end; FreeMem(p); TPrinterInfos(p^)[i].pPrinterName returns a 'P' for printer name. i have a PdfCreator installed as a printer. TPrinterInfos is an array of _PRINTER_INFO_2A. how can i fix this?

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  • StoreFilterField input doesn't react

    - by user1289877
    I'm trying to build grid with build in column filtering (using sencha gxt), here is my code: public Grid<Stock> createGrid() { // Columns definition ColumnConfig<Stock, String> nameCol = new ColumnConfig<Stock, String>(props.name(), 100, "Company"); // Column model definition and creation List<ColumnConfig<Stock, ?>> cl = new ArrayList<ColumnConfig<Stock, ?>>(); cl.add(nameCol); ColumnModel<Stock> cm = new ColumnModel<Stock>(cl); // Data populating ListStore<Stock> store = new ListStore<Stock>(props.key()); store.addAll(TestData.getStocks()); // Grid creation with data final Grid<Stock> grid = new Grid<Stock>(store, cm); grid.getView().setAutoExpandColumn(nameCol); grid.setBorders(false); grid.getView().setStripeRows(true); grid.getView().setColumnLines(true); // Filters definition StoreFilterField<Stock> filter = new StoreFilterField<Stock>() { @Override protected boolean doSelect(Store<Stock> store, Stock parent, Stock item, String filter) { // Window.alert(String.valueOf("a")); String name = item.getName(); name = name.toLowerCase(); if (name.startsWith(filter.toLowerCase())) { return true; } return false; } }; filter.bind(store); cm.addHeaderGroup(0, 0, new HeaderGroupConfig(filter, 1, 1)); filter.focus(); return grid; } My problem is: after I run this code, I cannot write anything to filter input, I'm using test data and classes (Stock.java and StockProperties.java) from this example: http://sencha.com/examples-dev/#ExamplePlace:filtergrid I try to put allert in doSelect method to check if this function was called, but it wasn't. Any idea will be welcome. Thanks.

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  • Searching with MATCH(), AGAINST() and AS score with mysqli and php

    - by Drew
    Below is the code I am using to search my table. I have made the relevant columns FULLTEXT in the table. This doesn't return me anything. Can someone tell me what it is that i'm doing wrong? Thanks in advance. $sql = 'SELECT id,uname,class,school, MATCH(uname, class, school) AGAINST(?) AS score FROM images WHERE MATCH(uname, class, school) AGAINST(? IN BOOLEAN MODE) ORDER BY score DES'; $stmt = $db_connection->prepare($sql); $stmt->bind_param('ss',$keyword,$keyword); $stmt->execute(); $stmt->store_result(); $stmt->bind_result($id,$uname,$class,$school); $xml = "<data>".PHP_EOL; while($stmt->fetch()){ $xml .= " <person>".PHP_EOL; $xml .= " <id>$id</id>".PHP_EOL; $xml .= " <name>$uname</name>".PHP_EOL; $xml .= " <class>$class</class>".PHP_EOL; $xml .= " <school>$school</school>".PHP_EOL; $xml .= " </person>".PHP_EOL; } $xml .= "</data>"; echo $xml; Below is an image of the indexes of the table:

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  • Scala newbie vproducer/consumer attempt running out of memory

    - by Nick
    I am trying to create a producer/consumer type Scala app. The LoopControl just sends a message to the MessageReceiver continually. The MessageReceiver then delegates work to the MessageCreatorActor (whose work is to check a map for an object, and if not found create one and start it up). Each MessageActor created by this MessageCreatorActor is associated with an Id. Eventually this is where I want to do business logic. But I run out of memory after 15 minutes. Its finding the cached actors,but quickly runs out of memory. Any help is appreciated. Or any one has any good code on producers consumers doing real stuff (not just adding numbers), please post. import scala.actors.Actor import java.util.HashMap import scala.actors.Actor._ case object LoopControl case object MessageReceiver case object MessageActor case object MessageActorCreator class MessageReceiver(msg: String) extends Actor { var messageActorMap = new HashMap[String, MessageActor] val messageCreatorActor = new MessageActorCreator(null, null) def act() { messageCreatorActor.start loop { react { case MessageActor(messageId) => if (msg.length() > 0) { var messageActor = messageActorMap.get(messageId); if(messageActor == null) { messageCreatorActor ! MessageActorCreator(messageId, messageActorMap) }else { messageActor ! MessageActor } } } } } } case class MessageActorCreator(msg:String, messageActorMap: HashMap[String, MessageActor]) extends Actor { def act() { loop { react { case MessageActorCreator(messageId, messageActorMap) => if(messageId != null ) { var messageActor = new MessageActor(messageId); messageActorMap.put(messageId, messageActor) println(messageActorMap) messageActor.start messageActor ! MessageActor } } } } } class LoopControl(messageReceiver:MessageReceiver) extends Actor { var count : Int = 0; def act() { while (true) { messageReceiver ! MessageActor ("00-122-0X95-FEC0" + count) //Thread.sleep(100) count = count +1; if(count > 5) { count = 0; } } } } case class MessageActor(msg: String) extends Actor { def act() { loop { react { case MessageActor => println() println("MessageActor: Got something-> " + msg) } } } } object messages extends Application { val messageReceiver = new MessageReceiver("bootstrap") val loopControl = new LoopControl(messageReceiver) messageReceiver.start loopControl.start }

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  • When are predicates appropriate and what is the best pattern for usage

    - by Maxim Gershkovich
    When are predicates appropriate and what is the best pattern for usage? What are the advantages of predicates? It seems to me like most cases where a predicate can be employed a tight loop would accomplish the same functionality? I don’t see a reusability argument given you will probably only implement a predicate in one method right? They look and feel nice but besides that they seem like you would only employ them when you need a quick hack on the collection classes? UPDATE But why would you be rewriting the tight loop again and again? In my mind/code when it comes to collections I always end up with something like Class Person End Class Class PersonList Inherits List(Of Person) Function FindByName(Name) as Person tight loop.... End Function End Class @Ani By that same logic I could implement the method as such Class PersonList Inherits List(Of Person) Function FindByName(Name) as PersonList End Function Function FindByAge(Age) as PersonList End Function Function FindBySocialSecurityNumber(SocialSecurityNumber) as PersonList End Function End Class And call it as such Dim res as PersonList = MyList.FindByName("Max").FindByAge(25).FindBySocialSecurityNumber(1234) and the result along with the amount of code and its reusability is largely the same, no? I am not arguing just trying to understand.

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  • How do I implement configurations and settings?

    - by Malvolio
    I'm writing a system that is deployed in several places and each site needs its own configurations and settings. A "configuration" is a named value that is necessary to a particular site (e.g., the database URL, S3 bucket name); every configuration is necessary, there is not usually a default, and it's typically string-valued. A setting is a named value but it just tweaks the behavior of the system; it's often numeric or Boolean, and there's usually some default. So far, I've been using property files or thing like them, but it's a terrible solution. Several times, a developer has added a requirement for a configuration but not added the value to file for the live configuration, so the new release passed all the tests, then failed when released to live. Better, of course, for every file to be compiled — so if there's a missing configuration, or one of the wrong type, it won't get past the compiler — and inject the site-specific class into the build for each site. As a bones, a Scala file can easy model more complex values, especially lists, but also maps and tuples. The downside is, the files are sometimes maintained by people who aren't developers, so it has to be pretty self-explanatory, which was the advantage of property files. (Someone explain XML configurations to me: all the complexity of a compilable file but the run-time risk of a property file.) What I'm looking for is an easy pattern for defining a group required names and allowable values. Any suggestions?

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  • Why should I override hashCode() when I override equals() method?

    - by Bragaadeesh
    Ok, I have heard from many places and sources that whenever I override the equals() method, I need to override the hashCode() method as well. But consider the following piece of code package test; public class MyCustomObject { int intVal1; int intVal2; public MyCustomObject(int val1, int val2){ intVal1 = val1; intVal2 = val2; } public boolean equals(Object obj){ return (((MyCustomObject)obj).intVal1 == this.intVal1) && (((MyCustomObject)obj).intVal2 == this.intVal2); } public static void main(String a[]){ MyCustomObject m1 = new MyCustomObject(3,5); MyCustomObject m2 = new MyCustomObject(3,5); MyCustomObject m3 = new MyCustomObject(4,5); System.out.println(m1.equals(m2)); System.out.println(m1.equals(m3)); } } Here the output is true, false exactly the way I want it to be and I dont care of overriding the hashCode() method at all. This means that hashCode() overriding is an option rather being a mandatory one as everyone says. I want a second confirmation.

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  • Is there a default way to get hold of an internal property in jQueryUi widget?

    - by prodigitalson
    Im using an existing widget from the jquery-ui labs call selectmenu. It has callback options for the events close and open. The problem is i need in these event to animate a node that is part of the widget but not what its connected to. In order to do this i need access to this node. for example if i were to actually modify the widget code itself: // ... other methods/properties "open" : function(event){ // ... the original logic // this is my animation $(this.list).slideUp('slow'); // this is the orginal call to _trigger this._trigger('open', event, $this._uiHash()); }, // ... other methods/properties However when in the scope of the event handler i attach this is the orginal element i called the widget on. I need the widget instance or specifically the widget instance's list property. $('select#custom').selectmenu({ 'open': function(){ // in this scope `this` is an HTMLSelectElement not the ui widget } }); Whats the best way to go about getting the list property from the widget?

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  • Reversible numerical calculations in Prolog

    - by user8472
    While reading SICP I came across logic programming chapter 4.4. Then I started looking into the Prolog programming language and tried to understand some simple assignments in Prolog. I found that Prolog seems to have troubles with numerical calculations. Here is the computation of a factorial in standard Prolog: f(0, 1). f(A, B) :- A > 0, C is A-1, f(C, D), B is A*D. The issues I find is that I need to introduce two auxiliary variables (C and D), a new syntax (is) and that the problem is non-reversible (i.e., f(5,X) works as expected, but f(X,120) does not). Naively, I expect that at the very least C is A-1, f(C, D) above may be replaced by f(A-1,D), but even that does not work. My question is: Why do I need to do this extra "stuff" in numerical calculations but not in other queries? I do understand (and SICP is quite clear about it) that in general information on "what to do" is insufficient to answer the question of "how to do it". So the declarative knowledge in (at least some) math problems is insufficient to actually solve these problems. But that begs the next question: How does this extra "stuff" in Prolog help me to restrict the formulation to just those problems where "what to do" is sufficient to answer "how to do it"?

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