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• Poor performance using RMI-proxies with Swing components

  - by Patrick

  I'm having huge performance issues when I add RMI proxy references to a Java Swing JList-component. I'm retrieving a list of user Profiles with RMI from a server. The retrieval itself takes just a second or so, so that's acceptable under the circumstances. However, when I try to add these proxies to a JList, with the help of a custom ListModel and a CellRenderer, it takes between 30-60 seconds to add about 180 objects. Since it is a list of users' names, it's preferrable to present them alphabetically. The biggest performance hit is when I sort the elements as they get added to the ListModel. Since the list will always be sorted, I opted to use the built-in Collections.binarySearch() to find the correct position for the next element to be added, and the comparator uses two methods that are defined by the Profile interface, namely getFirstName() and getLastName(). Is there any way to speed this process up, or am I simply implementing it the wrong way? Or is this a "feature" of RMI? I'd really love to be able to cache some of the data of the remote objects locally, to minimize the remote method calls.

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• How to append a row to a TableViewSection in Titanium?

  - by Mike Trpcic

  I'm developing an iPhone application in Titanium, and need to append a row to a particular TableViewSection. I can't do this on page load, as it's done dynamically by the user throughout the lifecycle of the application. The documentation says that the TableViewSection has an add method which takes two arguments, but I can't make it work. Here's my existing code: for(var i = 0; i <= product_count; i++){ productsTableViewSection.add( Ti.UI.createTableViewRow({ title:'Testing...' }) ); } That is just passing one argument in, and that causes Titanium to die with an uncaught exception: 2010-04-26 16:57:18.056 MyApplication[72765:207] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 2. The number of rows contained in an existing section after the update (2) must be equal to the number of rows contained in that section before the update (1), plus or minus the number of rows inserted or deleted from that section (0 inserted, 0 deleted).' 2010-04-26 16:57:18.056 MyApplication[72765:207] Stack: ( The exception looks like it did add the row, but it's not allowed to for some reason. Since the documentation says that TableViewSection takes in "view" and "row", I tried the following: for(var i = 0; i <= product_count; i++){ productsTableViewSection.add( Ti.UI.createView({}), Ti.UI.createTableViewRow({ title:'Testing...' }) ); } The above code doesn't throw the exception, but it gives a [WARN]: [WARN] Invalid type passed to function. expected: TiUIViewProxy, was: TiUITableViewRowProxy in -[TiUITableViewSectionProxy add:] (TiUITableViewSectionProxy.m:62) TableViewSections don't seem to support any methods like appendRow, or insertRow, so I don't know where else to go with this. I've looked through the KitchenSink app, but there are no examples that I could find of adding a row to a TableViewSection. Any help is appreciated.

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• Is XMLReader a SAX parser, a DOM parser, or neither?

  - by Renesis

  I am testing various methods to read (possibly large, and very often) XML configuration files in PHP. No writing is ever needed. I have two successful implementations, one using SimpleXML (which I know is a DOM parser) and one using XMLReader. I know that a DOM reader must read the whole tree and therefore uses more memory. My tests reflect that. I also know that A SAX parser is an "event-based" parser that uses less memory because it reads each node from the stream without checking what is next. XMLReader also reads from a stream with the cursor providing data about the node it is currently at. So, it definitely sounds like XMLReader (http://us2.php.net/xmlreader) is not a DOM parser, but my question is, is it a SAX parser, or something else? It seems like XMLReader behaves the way a SAX parser does but does not throw the events themselves (in other words, can you construct a SAX parser with XMLReader?) If it is something else, does the classification it's in have a name?

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• MVC2 DataAnnotations on ViewModel - Don't understand using it with MVVM pattern

  - by ScottSEA

  I have an MVC2 Application that uses MVVM pattern. I am trying use Data Annotations to validate form input. In my ThingsController I have two methods: [HttpGet] public ActionResult Index() { return View(); } public ActionResult Details(ThingsViewModel tvm) { if (!ModelState.IsValid) return View(tvm); try { Query q = new Query(tvm.Query); ThingRepository repository = new ThingRepository(q); tvm.Things = repository.All(); return View(tvm); } catch (Exception) { return View(); } } My Details.aspx view is strongly typed to the ThingsViewModel: <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<Config.Web.Models.ThingsViewModel>" %> The ViewModel is a class consisting of a IList of returned Thing objects and the Query string (which is submitted on the form) and has the Required data annotation: public class ThingsViewModel { public IList<Thing> Things{ get; set; } [Required(ErrorMessage="You must enter a query")] public string Query { get; set; } } When I run this, and click the submit button on the form without entering a value I get a YSOD with the following error: The model item passed into the dictionary is of type 'Config.Web.Models.ThingsViewModel', but this dictionary requires a model item of type System.Collections.Generic.IEnumerable`1[Config.Domain.Entities.Thing]'. How can I get Data Annotations to work with a ViewModel? I cannot see what I'm missing or where I'm going wrong - the VM was working just fine before I started mucking around with validation.

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• Custom control doesn't fire validation

  - by Ed Woodcock

  I've written a custom ASP.net control that descends from LinkButton and overrides the Render() method. I'm using it to replace ImageButtons in the site I'm working on so we don't have to have an image for each button. This control works fine, does the required post-backs etc., however it doesn't fire the validators in its validation group. This is obviously an issue. The code for the control is (condensed) as follows: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; public class CustomButton : LinkButton { public string SpanCssClass { get; set; } protected override void Render(HtmlTextWriter writer) { if (!Visible) { return; } writer.AddAttribute(HtmlTextWriterAttribute.Name, UniqueID); writer.AddAttribute(HtmlTextWriterAttribute.Id, ClientID); writer.AddAttribute(HtmlTextWriterAttribute.Class, CssClass); string postback = string.IsNullOrEmpty(OnClientClick) ? "javascript:__doPostBack('" + UniqueID + "','');" : OnClientClick; writer.AddAttribute(HtmlTextWriterAttribute.Href, postback); writer.RenderBeginTag(HtmlTextWriterTag.A); writer.AddAttribute(HtmlTextWriterAttribute.Class, SpanCssClass); writer.RenderBeginTag(HtmlTextWriterTag.Span); writer.Write(Text); writer.RenderEndTag(); writer.RenderEndTag(); } } Does anyone know why this would not be causing the validators to fire? I was under the impression that leaving all the other methods in LinkButton un-overridden would leave all the other functionality the same!

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• Scrum - Responding to traditional RFPs

  - by Todd Charron

  Hi all, I've seen many articles about how to put together Agile RFP's and negotiating agile contracts, but how about if you're responding to a more traditional RFP? Any advice on how to meet the requirements of the RFP while still presenting an agile approach? A lot of these traditional RFP's request specific technical implementations, timelines, and costs, while also requesting exact details about milestones and how the technical solutions will be implemented. While I'm sure in traditional waterfall it's normal to pretend that these things are facts, it seems wrong to commit to something like this if you're an agile organization just to get through the initial screening process. What methods have you used to respond to more traditional RFP's? Here's a sample one grabbed from google, http://www.investtoronto.ca/documents/rfp-web-development.pdf Particularly, "3. A detailed work plan outlining how they expect to achieve the four deliverables within the timeframe outlined. Plan for additional phases of development." and "8. The detailed cost structure, including per diem rates for team members, allocation of hours between team members, expenses and other out of pocket disbursements, and a total upset price."

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• Awkward looking uses of Contract.ValueAtReturn()

  - by devoured elysium

  I am designing a method that will add an element to an internal list. The structure of the class is something along the lines of: class MyCustomerDatabase { private IList<Customer> _customers = new List<Customer>(); public int NumberOfCustomers { get { return _customers; } } public void AddCustomer(Customer customer) { _customers.Add(customer); } } Now, I was thinking of adding a Contract.Ensures() about the size of the _customers growing by 1 with this call. The problem is that I end up with some weird looking code: public void AddCustomer(Customer customer) { int numberOfCustomersAtReturn; Contract.Ensures(Contract.ValueAtReturn<int>(out numberOfCustomersAtReturn) == Contract.OldValue<int>(NumberOfCustomers) + 1); _customers.Add(customer); numberOfCustomersAtReturn = NumberOfCustomers; } The main problem is that properties are in fact methods, so you can't just reference them direcly when using Contract.ValueAtReturn() as its only parameter accepts variables as out. The situation gets even odder if I want to achieve the same but this time with a method that should return a value: public int MyReturningMethod() { ... return abc(); //abc will add by one the number of customers in list } //gets converted to public int MyReturningMethod() { int numberOfCustomersAtReturn; Contract.Ensures(Contract.ValueAtReturn<int>(out numberOfCustomersAtReturn) == Contract.OldValue<int>(NumberOfCustomers) + 1); int returnValue = abc(); numberOfCustomersAtReturn = NumberOfCustomers; return returnValue; } This seems pretty clumsy :( Code Contracts should aim to get things clearer and this seems right the opposite. Am I doing something wrong? Thanks

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• Persistant Http client connections in java

  - by Akusete

  I am trying to write a simple Http client application in Java and am a bit confused by the seemingly different ways to establish Http client connections, and efficiently re-use the objects. Current I am using the following steps (I have left out exception handling for simplicity) Iterator<URI> uriIterator = someURIs(); HttpClient client = new DefaultHttpClient(); while (uriIterator.hasNext()) { URI uri = uriIterator.next(); HttpGet request = new HttpGet(uri); HttpResponse response = client.execute(request); HttpEntity entity = response.getEntity(); InputStream s = entity.getContent(); processStream (); s.close(); } In regard to the code above, my questions is: Assuming all URI's are pointing to the same host (but different resources on that host). What is the recommended way to use a single http connection for all requests? And how do you close the connection after the last request? --edit: Also what is the difference between using uri.openConnection(), versus HttpClient? Which is preferable, and what other methods exist?

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• OOP - Handling Automated Instances of a Class - PHP

  - by dscher

  This is a topic that, as a beginner to PHP and programming, sort of perplexes me. I'm building a stockmarket website and want users to add their own stocks. I can clearly see the benefit of having each stock be a class instance with all the methods of a class. What I am stumped on is the best way to give that instance a name when I instantiate it. If I have: class Stock() { ....doing stuff..... } what is the best way to give my instances of it a name. Obviously I can write: $newStock = new Stock(); $newStock.getPrice(); or whatever, but if a user adds a stock via the app, where can the name of that instance come from? I guess that there is little harm in always creating a new child with $newStock = new Stock() and then storing that to the DB which leads me to my next question! What would be the best way to retrieve 20 user stocks(for example) into instances of class Stock()? Do I need to instantiate 20 new instances of class Stock() every time the user logs in or is there something I'm missing? I hope someone answers this and more important hope a bunch of people answer this and it somehow helps someone else who is having a hard time wrapping their head around what probably leads to a really elegant solution. Thanks guys!

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• Issue calling superclass method in subclass constructor

  - by stormin986

  I get a NullPointerException calling a Superclass Method in Subclass Inner Class Constructor... What's the Deal? In my application's main class (subclass of Application), I have a public inner class that simply contains 3 public string objects. In the parent class I declare an object of that inner class. public class MainApplication extends Application { public class Data { public String x; public String y; public String z; } private Data data; MainApplication() { data = new Data() data.x = SuperClassMethod(); } } After I instantiate the object in the constructor, I get a runtime error when I try to assign a value in the inner class with a superclass method. Any idea what's up here?? Can you not call superclass methods in the subclass constructor? ** Edit ** Original question was about inner class member assignment in outer class constructor. Turned out the issue was with calling a superclass method in the class's constructor. It was giving me a null pointer exception. Thus, the question has changed.

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• Returning objects from another thread?

  - by Mark

  Trying to follow the hints laid out here, but she doesn't mention how to handle it when your collection needs to return a value, like so: private delegate TValue DequeueHandler(); public virtual TValue Dequeue() { if (dispatcher.CheckAccess()) { --count; var pair = dict.First(); var queue = pair.Value; var val = queue.Dequeue(); if (queue.Count == 0) dict.Remove(pair.Key); OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, val)); return val; } else { dispatcher.BeginInvoke(new DequeueHandler(Dequeue)); } } This obviously won't work, because dispatcher.BeginInvoke doesn't return anything. What am I supposed to do? Or maybe I could replace dequeue with two functions, Peek and Pop, where Peek doesn't really need to be on the UI thread because it doesn't modify anything, right? As a side question, these methods don't need to be "locked" either, do they? If they're all forced to run in the UI thread, then there shouldn't be any concurrency issues, right?

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• Passing arguments and values from HTML to jQuery (events)

  - by Jaroslav Moravec

  What is the practice to pass arguments from HTML to jQuery events function. For example getting id of row from db: <tr class="jq_killMe" id="thisItemId-id"> ... </tr> and jQuery: $(".jq_killMe").click(function () { var tmp = $(this).attr('id).split("-"); var id = tmp[0] // ... } What's the best practise, if I want to pass more than one argument? Is it better not to use jQuery? For example: <tr onclick="killMe('id')"> ... </tr> I didn't find the answer on my question, I will be glad even for links. Thanks. Edit (pre solution) So you suggested two methods to do that: Add custom attributes to element (XHTML) Use attribute ID and parse it by regex Attribute data-* attributes in HTML5 Use hidden children elements I like first solution, but... I would like to (I have to (employer)) produce valid code. Here is a nice question and answers: http://stackoverflow.com/questions/994856/so-what-if-custom-html-attributes-arent-valid-xhtml And the second is not so pretty as the first, but valid. So the compromise is... The third is the solution for future, but here is a lot of CMS where we have to use XHTML or HTML4. (And HTML5 is the long process)

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• noncopyable static const member class in template class

  - by Dukales

  I have a non-copyable (inherited from boost::noncopyable) class that I use as a custom namespace. Also, I have another class, that uses previous one, as shown here: #include <boost/utility.hpp> #include <cmath> template< typename F > struct custom_namespace : boost::noncopyable { F sqrt_of_half(F const & x) const { using std::sqrt; return sqrt(x / F(2.0L)); } // ... maybe others are not so dummy const/constexpr methods }; template< typename F > class custom_namespace_user { static ::custom_namespace< F > const custom_namespace_; public : F poisson() const { return custom_namespace_.sqrt_of_half(M_PI); } static F square_diagonal(F const & a) { return a * custom_namespace_.sqrt_of_half(1.0L); } }; template< typename F > ::custom_namespace< F > const custom_namespace_user< F >::custom_namespace_(); this code leads to the next error (even without instantiation): error: no 'const custom_namespace custom_namespace_user::custom_namespace_()' member function declared in class 'custom_namespace_user' The next way is not legitimate: template< typename F ::custom_namespace< F const custom_namespace_user< F ::custom_namespace_ = ::custom_namespace< F (); What should I do to declare this two classes (first as noncopyable static const member class of second)? Is this feaseble?

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• How to build a Django form which requires a delay to be re-submitted ?

  - by pierre-guillaume-degans

  Hey, In order to avoid spamming, I would like to add a waiting time to re-submit a form (i.e. the user should wait a few seconds to submit the form, except the first time that this form is submitted). To do that, I added a timestamp to my form (and a security_hash field containing the timestamp plus the settings.SECRET_KEY which ensures that the timestamp is not fiddled with). This look like: class MyForm(forms.Form): timestamp = forms.IntegerField(widget=forms.HiddenInput) security_hash = forms.CharField(min_length=40, max_length=40, widget=forms.HiddenInput) # + some other fields.. # + methods to build the hash and to clean the timestamp... # (it is based on django.contrib.comments.forms.CommentSecurityForm) def clean_timestamp(self): """Make sure the delay is over (5 seconds).""" ts = self.cleaned_data["timestamp"] if not time.time() - ts > 5: raise forms.ValidationError("Timestamp check failed") return ts # etc... This works fine. However there is still an issue: the timestamp is checked the first time the form is submitted by the user, and I need to avoid this. Any idea to fix it ? Thank you ! :-)

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• converting a timestring to a duration

  - by radman

  Hi, At the moment I am trying to read in a timestring formatted and create a duration from that. I am currently trying to use the boost date_time time_duration class to read and store the value. boost date_time provides a method time_duration duration_from_string(std::string) that allows a time_duration to be created from a time string and it accepts strings formatted appropriately ("[-]h[h][:mm][:ss][.fff]".). Now this method works fine if you use a correctly formatted time string. However if you submit something invalid like "ham_sandwich" or "100" then you will still be returned a time_duration that is not valid. Specifically if you try to pass it to a standard output stream then an assertion will occur. My question is: Does anyone know how to test the validity of the boost time_duration? and failing that can you suggest another method of reading a timestring and getting a duration from it? Note: I have tried the obvious testing methods that time_duration provides; is_not_a_date_time(), is_special() etc and they don't pick up that there is an issue. Using boost 1.38.0

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• @PrePersist with entity inheritance

  - by gerry

  I'm having some problems with inheritance and the @PrePersist annotation. My source code looks like the following: _the 'base' class with the annotated updateDates() method: @javax.persistence.Entity @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS) public class Base implements Serializable{ ... @Id @GeneratedValue protected Long id; ... @Column(nullable=false) @Temporal(TemporalType.TIMESTAMP) private Date creationDate; @Column(nullable=false) @Temporal(TemporalType.TIMESTAMP) private Date lastModificationDate; ... public Date getCreationDate() { return creationDate; } public void setCreationDate(Date creationDate) { this.creationDate = creationDate; } public Date getLastModificationDate() { return lastModificationDate; } public void setLastModificationDate(Date lastModificationDate) { this.lastModificationDate = lastModificationDate; } ... @PrePersist protected void updateDates() { if (creationDate == null) { creationDate = new Date(); } lastModificationDate = new Date(); } } _ now the 'Child' class that should inherit all methods "and annotations" from the base class: @javax.persistence.Entity @NamedQueries({ @NamedQuery(name=Sensor.QUERY_FIND_ALL, query="SELECT s FROM Sensor s") }) public class Sensor extends Entity { ... // additional attributes @Column(nullable=false) protected String value; ... // additional getters, setters ... } If I store/persist instances of the Base class to the database, everything works fine. The dates are getting updated. But now, if I want to persist a child instance, the database throws the following exception: MySQLIntegrityConstraintViolationException: Column 'CREATIONDATE' cannot be null So, in my opinion, this is caused because in Child the method "@PrePersist protected void updateDates()" is not called/invoked before persisting the instances to the database. What is wrong with my code?

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• accessing a method from a button within a class?

  - by flo

  #import "GameObject.h" #import "Definitions.h" @implementation GameObject @synthesize owner; @synthesize state; @synthesize mirrored; @synthesize button; @synthesize switcher; - (id) init { if ( self = [super init] ) { [self setOwner: EmptyField]; button = [UIButton buttonWithType:UIButtonTypeCustom]; [self setSwitcher: FALSE]; } return self; } - (UIButton*) display{ button.frame = CGRectMake(0, 0, GO_Width, GO_Height); [button setBackgroundImage:[UIImage imageNamed:BlueStone] forState:UIControlStateNormal]; [button addTarget:self action:@selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside]; return button; } -(void)buttonPressed:(id) sender { //... } } - (void) dealloc { [super dealloc]; } @end Hi! i would like to know if the above is possible somehow within a class (in my case it is called GameObject) or if i HAVE to have the button call a methode in the viewcontroller... the above results with the app crashing. i would call display within a loop on the viewcontroller and id like to change some of the GameObjects instance variables within buttonPressed. Also id like to change some other stuff by calling some other methods from within buttonPressed but i think that will be the lesser of my problems ;) also id like to know how i can pass some variables to the buttonPressed method... cant find it anywhere :( help on this one would be much appreciated ;) thanks flo

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• Checking for valid email addresses

  - by Roland

  I'm running a website with more than 60 000 registered users. Every week notifications are send to these users via email, now I've noticed some of the mail addresses do not exists anymore eg. the domain address is valid but the email name en asdas@ is not valid anymore since person does not work at a company anymore etc. Now I'm looping through the database and doing some regular expression checks and checking if the MX records exist with the following two functions function verify_email($email){ if(!preg_match('/^[_A-z0-9-]+((\.|\+)[_A-z0-9-]+)*@[A-z0-9-]+(\.[A-z0-9-]+)*(\.[A-z]{2,4})$/',$email)){ return false; } else { return true; } } // Our function to verify the MX records function verify_email_dns($email){ list($name, $domain) = split('@',$email); if(!checkdnsrr($domain,'MX')){ return false; } else { return true; } } If the email address is in an invalid format or the domain does not exists I delete the users account. Are there any methods I could use to check if the email address still exists or not if the domain name is valid and the email address is in the correct format? For example [email protected] does not exist anymore but test.com is a valid domain name.

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• How to retrieve view of MultiIndex DataFrame

  - by Henry S. Harrison

  This question was inspired by this question. I had the same problem, updating a MultiIndex DataFrame by selection. The drop_level=False solution in Pandas 0.13 will allow me to achieve the same result, but I am still wondering why I cannot get a view from the MultiIndex DataFrame. In other words, why does this not work?: >>> sat = d.xs('sat', level='day', copy=False) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "C:\Python27\lib\site-packages\pandas\core\frame.py", line 2248, in xs raise ValueError('Cannot retrieve view (copy=False)') ValueError: Cannot retrieve view (copy=False) Of course it could be only because it is not implemented, but is there a reason? Is it somehow ambiguous or impossible to implement? Returning a view is more intuitive to me than returning a copy then later updating the original. I looked through the source and it seems this situation is checked explicitly to raise an error. Alternatively, is it possible to get the same sort of view from any of the other indexing methods? I've experimented but have not been successful. [edit] Some potential implementations are discussed here. I guess with the last question above I'm wondering what the current best solution is to index into arbitrary multiindex slices and cross-sections.

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• C++ Problems with #import of .NET out-of-proc server.

  - by jm

  In C++ program, I am trying to #import TLB of .NET out of proc server. I get errors like: z:\server.tlh(111) : error C2146: syntax error : missing ';' before identifier 'GetType' z:\server.tlh(111) : error C2501: 'TypePtr' : missing storage-class or type specifiers z:\server.tli(74) : error C2143: syntax error : missing ';' before 'tag::id' z:\server.tli(74) : error C2433: 'TypePtr' : 'inline' not permitted on data declarations z:\server.tli(74) : error C2501: '_TypePtr' : missing storage-class or type specifiers z:\server.tli(74) : fatal error C1004: unexpected end of file found The TLH looks like: ... _bstr_t GetToString ( ); VARIANT_BOOL Equals ( const _variant_t & obj ); long GetHashCode ( ); _TypePtr GetType ( ); long Open ( ); ... I am not really interested in the having the base object .NET object methods like GetType(), Equals(), etc. But GetType() seems to be causing problems. Some google research indicates I could #import MSCORLIB.TLB (or put it in path), but I can't get that to compile either. Any tips?

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• Cast object to interface when created via reflection

  - by Al

  I'm trying some stuff out in Android and I'm stuck at when trying to cast a class in another .apk to my interface. I have the interface and various classes in other .apks that implement that interface. I find the other classes using PackageManager's query methods and use Application#createPackageContext() to get the classloader for that context. I then load the class, create a new instance and try to cast it to my interface, which I know it definitely implements. When I try to cast, it throws a class cast exception. I tried various things like loading the interface first, using Class#asSubclass, etc, none of which work. Class#getInterfaces() shows the interface is implemented. My code is below: PackageManager pm = getPackageManager(); List<ResolveInfo> lr = pm.queryIntentServices(new Intent("com.example.some.action"), 0); ArrayList<MyInterface> list = new ArrayList<MyInterface>(); for (ResolveInfo r : lr) { try { Context c = getApplication().createPackageContext(r.serviceInfo.packageName, Context.CONTEXT_IGNORE_SECURITY | Context.CONTEXT_INCLUDE_CODE); ClassLoader cl = c.getClassLoader(); String className = r.serviceInfo.name; if (className != null) { try { Class<?> cls = cl.loadClass(className); Object o = cls.newInstance(); if (o instanceof MyInterface) { //fails list.add((MyInterface) o); } } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } // some exceptions removed for readability } } catch (NameNotFoundException e1) { e1.printStackTrace(); }

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• What are Code Smells? What is the best way to correct them?

  - by Rob Cooper

  OK, so I know what a code smell is, and the Wikipedia Article is pretty clear in its definition: In computer programming, code smell is any symptom in the source code of a computer program that indicates something may be wrong. It generally indicates that the code should be refactored or the overall design should be reexamined. The term appears to have been coined by Kent Beck on WardsWiki. Usage of the term increased after it was featured in Refactoring. Improving the Design of Existing Code. I know it also provides a list of common code smells. But I thought it would be great if we could get clear list of not only what code smells there are, but also how to correct them. Some Rules Now, this is going to be a little subjective in that there are differences to languages, programming style etc. So lets lay down some ground rules: ** ONE SMELL PER ANSWER PLEASE! & ADVISE ON HOW TO CORRECT! ** See this answer for a good display of what this thread should be! DO NOT downmod if a smell doesn't apply to your language or development methodology We are all different. DO NOT just quickly smash in as many as you can think of Think about the smells you want to list and get a good idea down on how to work around. DO downmod answers that just look rushed For example "dupe code - remove dupe code". Let's makes it useful (e.g. Duplicate Code - Refactor into separate methods or even classes, use these links for help on these common.. etc. etc.). DO upmod answers that you would add yourself If you wish to expand, then answer with your thoughts linking to the original answer (if it's detailed) or comment if its a minor point. DO format your answers! Help others to be able to read it, use code snippets, headings and markup to make key points stand out!

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• [JAX-B] How can I ignore a superclass?

  - by MrSpandex

  I'm trying to write a web service for the java.util.logging api. So I wrote a class MyLogRecord that inherits from LogRecord. I annotated this class with JAX-B annotations, including @XmlAccessorType(XmlAccessType.NONE) so it would ignore non-annotated fields and properties. When I start up tomcat, I get errors that java.util.logging.Level and other java.util.logging classes do not have a default constructor, but none of my annotated methods make any reference to the Level class or any of the other java.util.logging classes. These are referenced by the parent class. My sub-class has everything it needs defined. How can I get JAX-B to ignore the parent class completely? Update: I found another post on this, which suggests modifying the parent class. This is obviously not possible because I am extending a java.util class. IS there any way to do this without modifying the superclass? Update2: I found a thread on java.net for a similar problem. That thread resulted in an enhancement request, which was marked as a duplicate of another issue, which resulted in the @XmlTransient annotation. The comments on these bug reports lead me to believe this is impossible in the current spec.

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• How do I implement a listener pattern over RMI using Spring?

  - by predhme

  So here is a generalized version of our application desgin: @Controller public class MyController { @Autowired private MyServiceInterface myServiceInterface; @RequestMapping("/myURL") public @ResponseBody String doSomething() { MyListenerInterface listener = new MyListenerInterfaceImpl(); myServiceInterface.doThenCallListener(listener); // do post stuff } } public interface MyListenerInterface { public void callA(); public void callB(); } public class MyListenerInterfaceImpl implements MyListenerInterface { // ... omitted for clarity } public interface MyServiceInterface { public void doThenCallListener(MyListenerInterface listener); } public class MyServiceImpl { public void doThenCallListener(MyListenerInterface listener) { // do stuff listener.callA(); } } Basically I have a controller that is being called via AJAX in which I am looking to return a response as a string. However, I need to make a call to the backend (MyServiceInterface). That guy is exposed through RMI by using Spring (man that was easy). But the service method as described requires a listener to be registered for invokation completion purposes. So what I assume I need to achieve is transparently to the backend make it so that when the listener methods are called, really the call is going over RMI. I would have thought Spring would have a simple way to wrap a POJO (not a service singleton) with RMI calls. I looked through their documentation but they had nothing besides exposing services via RMI. Could someone point me in the right direction?

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• Byte-Pairing for data compression

  - by user1669533

  Question about Byte-Pairing for data compression. If byte pairing converts two byte values to a single byte value, splitting the file in half, then taking a gig file and recusing it 16 times shrinks it to 62,500,000. My question is, is byte-pairing really efficient? Is the creation of a 5,000,000 iteration loop, to be conservative, efficient? I would like some feed back on and some incisive opinions please. Dave, what I read was: "The US patent office no longer grants patents on perpetual motion machines, but has recently granted at least two patents on a mathematically impossible process: compression of truly random data." I was not inferring the Patent Office was actually considering what I am inquiring about. I was merely commenting on the notion of a "mathematically impossible process." If someone has, in some way created a method of having a "single" data byte as a placeholder of 8 individual bytes of data, that would be a consideration for a patent. Now, about the mathematically impossibility of an 8 to 1 compression method, it is not so much a mathematically impossibility, but a series of rules and conditions that can be created. As long as there is the rule of 8 or 16 bit representation of storing data on a medium, there are ways to manipulate data that mirrors current methods, or creation by a new way of thinking.

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