Search Results

Search found 50247 results on 2010 pages for 'base class'.

Page 462/2010 | < Previous Page | 458 459 460 461 462 463 464 465 466 467 468 469  | Next Page >

  • Getting a Type variable knowing the name of type C#

    - by StuffHappens
    Hello! I'm developing a TypeTranslator class which has a method Type TranslateType(Type type). This method gets a type of an interface and if there's a class of interface name without leading I it creates it, otherwise an exception is raised. Here's some code to clearify what's written before: class Program { interface IAnimal { } class Animal : IAnimal { } void Function() { TypeTranslator typeTranslator = new TypeTranslator(); Assert(typeTranslator.TranslateType(typeof(IAnimal) == typeof(Animal))); } } Is it possible to get what I want? Thank you for your help!

    Read the article

  • Setting custom SQL in django admin

    - by eugene y
    I'm trying to set up a proxy model in django admin. It will represent a subset of the original model. The code from models.py: class MyManager(models.Manager): def get_query_set(self): return super(MyManager, self).get_query_set().filter(some_column='value') class MyModel(OrigModel): objects = MyManager() class Meta: proxy = True Now instead of filter() I need to use a complex SELECT statement with JOINS. What's the proper way to inject it wholly to the custom manager?

    Read the article

  • Is there an efficient way to write this PHP if / else statement?

    - by nvoyageur
    I've written a simple issue tracker for my web app. I have some comments that I want to keep private (only a role of 'root' can see them). Is there a better way to write the following so I do not need the empty else section? $role will be 'root' or some other values $is_private will be true if the comment is private <?php // Don't show private comments to non-root users if ($is_private && 'root' != $role): // NON Root cannot see private else: ?> <div class="comment <?= $is_private ? 'private' : '' ; ?>"> <div class="comment-meta toolbar"> <?= $is_private ? 'PRIVATE - ': ''; ?> <span class="datestamp"><?= $created_at; ?></span> - <span class="fullname"><?= $fname . ' ' . $lname; ?></span></div> <p class="content"><?= nl2br($body); ?></p> </div> <?php endif; ?>

    Read the article

  • Showing multiple elements onClick

    - by Nimbuz
    HTML: <ul id="mode"> <li><a href="#tab1">tab1</a> <div class="extra">tada</div> </li> <li><a href="#tab2">tab2</a> <div class="extra">tada</div> </li> </ul> <div id="tab1" class="tab-content" style="display: none">content 1</div> <div id="tab2" class="tab-content" style="display: none">content 2</div> ? jQuery: $(function(){ var mode = $('#mode'); var arrow = $('<span/>', {'class': 'arrow'}); $('li a', mode).bind('click.mytabs', function() { $('li', mode).removeClass('active'); $(this).parent().addClass('active').append(arrow); var a = $(this).attr('href'); $('.tab-content').hide(); $(a).show(); return false; }).filter(':first').triggerHandler('click.mytabs'); // eq(0) works as well }); JSFiddle here: http://jsfiddle.net/wwMJL/ I'd like to also show each li's 'extra' div on click and hide when the tab is inactive, what do I need to change in the code? Thanks!

    Read the article

  • ConfigurationSection with multiple projects

    - by shivesh
    In my asp.net solution i have a couple of class library-projects that act as modules of the site. In main project I have SiteConfigurationSection class that derives from ConfigurationSection. I want all projects to be able to access and use this SiteConfigurationSection. But class library projects can't access it because they obviously don't have a reference to the website itself. Should create a special library-project for SiteConfigurationSection of maybe it's better to create a mini SiteConfigurationSection class in every project and encapsulate only the needed values?

    Read the article

  • in vb.net an error is coming

    - by user275111
    Compiler Error Message: ASPNET: Make sure that the class defined in this code file matches the 'inherits' attribute, and that it extends the correct base class (e.g. Page or UserControl). in vb code-i used namespace and a class.

    Read the article

  • Django: How can I add weight/ordering to a many to many relationship?

    - by Klaas van Schelven
    I'm having Pages with TextBlocks on them. Text Blocks may appear on different pages, pages may have several text blocks on them. Every page may have these blocks in an ordering of it's own. This can be solved by using a separate through parameter. Like so: class TextBlock(models.Model): title = models.CharField(max_length=255) text = models.TextField() class Page(models.Model): textblocks = models.ManyToManyField(TextBlock, through=OrderedTextBlock) class OrderedTextBlock(models.Model): text_block = models.ForeignKey(TextBlock) product_page = models.ForeignKey(ProductPage) weight = models.IntegerField() class Meta: ordering = ('weight',) But I'm not very enthousiastic about the violations of DRY for my app. (There's a lot of ordered ManyToMany relations). Is there a recommended way to go about this?

    Read the article

  • IE: position two text lines on top and bottom corners in table cell?

    - by diggonce
    I have a table with dynamic data. And there is a specific line of text which should be displayed only when a user hovers over the table row. This line of text should be 'fixed' to the table cell's bottom edge. It works so far with Firefox, but fails in IE. Live code can be seen here: http://2010resolutions.org/test/index.html The text in red should be fixed to the table cell's bottom border. (They will have a fixed height and width) Any clues how to get this working in IE? Any help is appreciated. Here's the code: <style> table { width: 500px; background: gray; } td { vertical-align: top; } .wrapper { position: relative; background: green; } tr, td, .wrapper { height: 100%; padding-bottom: 0.75em; } .bottom { position: absolute; left: 0; bottom: 0; background: red; } .bottom { visibility: hidden; } tr:hover .bottom { visibility: visible; } </style> <table> <tr class="data"> <td> <div class="wrapper"> This is line 1<br /> This is line 2<br /> This is line 3<br /> <span class="bottom">Bottom line 1</span> </div> </td> <td> <div class="wrapper"> This is line 4<br /> This is line 5<br /> This is line 6<br /> <span class="bottom">Bottom line 2</span></span> </div> </td> <td> <div class="wrapper"> This is line 7<br /> This is line 8<br /> This is line 9<br /> This is line 10<br /> This is line 11<br /> This is line 12<br /> <span class="bottom">Bottom line 3</span> </div> </td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </table>

    Read the article

  • What do I need to change to get this 'acts_as_rateable' Rails plugin working with this code from the

    - by tepidsam
    Hello! I'm working my way through the 'Foundation Rails 2' book. In Chapter 9, we are building a little "plugins" app. In the book, he installs the acts_as_rateable plugin found at http://juixe.com/svn/acts_as_rateable. This plugin doesn't appear to exist in 2010 (the page for this "old" plugin seems to be working again...it was down when I tried it earlier), so I found another acts_as_rateable plugin at http://github.com/azabaj/acts_as_rateable. These plugins are different and I'm trying to get the "new" plugin working with the code/project/app from the Foudations 2 book. I was able to use the migration generator included with the "new" plugin and it worked. Now,though, I'm a bit confused. In the book, he has us create a new controller to work with the plugin (the old plugin). Here's the code for that: class RatingsController < ApplicationController def create @plugin = Plugin.find(params[:plugin_id]) rating = Rating.new(:rating => params[:rating]) @plugin.ratings << average_rating redirect_to @plugin end end Then he had us change the routing: map.resources :plugins, :has_many => :ratings map.resources :categories map.root :controller => 'plugins' Next, we modified the following to the 'show' template so that it looks like this: <div id="rate_plugin"> <h2>Rate this plugin</h2> <ul class="star-rating"> <li> <%= link_to "1", @plugin.rate_it(1), :method => :post, :title => "1 star out of 5", :class => "one-star" %> </li> <li> <%= link_to "2", plugin_ratings_path(@plugin, :rating => 2), :method => :post, :title => "2 stars out of 5", :class => "two-stars" %> </li> <li> <%= link_to "3", plugin_ratings_path(@plugin, :rating => 3), :method => :post, :title => "3 stars out of 5", :class => "three-stars" %> </li> <li> <%= link_to "4", plugin_ratings_path(@plugin, :rating => 4), :method => :post, :title => "4 stars out of 5", :class => "four-stars" %> </li> <li> <%= link_to "5", plugin_ratings_path(@plugin, :rating => 5), :method => :post, :title => "5 stars out of 5", :class => "five-stars" %> </li> </ul> </div> The problem is that we're using code for a different plugin. When I try to actually "rate" one of the plugins, I get an "unknown attribute" error. That makes sense. I'm using attribute names for the "old" plugin, but I should be using attributes names for the "new" plugin. The problem is...I've tried using a variety of different attribute names and I keep getting the same error. From the README for the "new" plugin, I think I should be using some of these but I haven't been able to get them working: Install the plugin into your vendor/plugins directory, insert 'acts_as_rateable' into your model, then restart your application. class Post < ActiveRecord::Base acts_as_rateable end Now your model is extended by the plugin, you can rate it ( 1-# )or calculate the average rating. @plugin.rate_it( 4, current_user.id ) @plugin.average_rating #=> 4.0 @plugin.average_rating_round #=> 4 @plugin.average_rating_percent #=> 80 @plugin.rated_by?( current_user ) #=> rating || false Plugin.find_average_of( 4 ) #=> array of posts See acts_as_rateable.rb for further details! I'm guessing that I might have to make some "bigger" changes to get this plugin working. I'm asking this question to learn and only learn. The book gives code to get things working with the old plugin, but if one were actually building this app today it would be necessary to use this "new" plugin, so I would like to see how it could be used. Cheers! Any ideas on what I could change to get the "new" plugin working?

    Read the article

  • C++ and Dependency Injection in unit testing

    - by lhumongous
    Suppose I have a C++ class like so: class A { public: A() { } void SetNewB( const B& _b ) { m_B = _b; } private: B m_B; } In order to unit test something like this, I would have to break A's dependency on B. Since class A holds onto an actual object and not a pointer, I would have to refactor this code to take a pointer. Additionally, I would need to create a parent interface class for B so I can pass in my own fake of B when I test SetNewB. In this case, doesn't unit testing with dependency injection further complicate the existing code? If I make B a pointer, I'm now introducing heap allocation, and some piece of code is now responsible for cleaning it up (unless I use ref counted pointers). Additionally, if B is a rather trivial class with only a couple of member variables and functions, why introduce a whole new interface for it instead of just testing with an instance of B? I suppose you could make the argument that it would be easier to refactor A by using an interface. But are there some cases where two classes might need to be tightly coupled?

    Read the article

  • Most proper way to use inherited classes with shared scopes in Mongo?

    - by Trip
    I have the TestVisual class that is inherited by the Game class : class TestVisual < Game include MongoMapper::Document end class Game include MongoMapper::Document belongs_to :maestra key :incorrect, Integer key :correct, Integer key :time_to_complete, Integer key :maestra_id, ObjectId timestamps! end As you can see it belongs to Maestra. So I can do Maestra.first.games But I can not to Maestra.first.test_visuals Since I'm working specifically with TestVisuals, that is ideally what I would like to pull. Is this possible with Mongo. If it isn't or if it isn't necessary, is there any other better way to reach the TestVisual object from Maestra and still have it inherit Game ?

    Read the article

  • Generics limitation, or lack of skillz ?

    - by Two Shoes
    I want to define the following class as such: public class CollectionAttribute<E extends Collection<T>> { private String name; private E value; public CollectionAttribute(String name, E value) { this.name = name; this.value = value; } public E getValue() { return value; } public void addValue(T value) { value.add(T); } } This won't compile (cannot resolve symbol T). If I replace the class declaration with the following: public class CollectionAttribute<E extends Collection<?>> Then I can't reference the parametrized type of the collection. Am I missing something or have I reached a limitation with generics in Java ?

    Read the article

  • Grails: How can I search through children in a hasMany relationship?

    - by intargc
    If I have a Client domain class, and that Client hasMany Courses. How do I find the course I'm looking for? For instance: class Client { String name static hasMany = [courses:Course] } class Course { String name static belongsTo = [client:Client] } def client = Client.get(1) I want to "find" or "search" within that courses relationship. Maybe something like: client.courses.find(name:'Whatever') Is there any way to do this with Grails?

    Read the article

  • Override jre_lib classes

    - by Filip
    What is the best way to override jre_lib classes? Let's say I need to store all ArrayLists not in RAM but on disk or anywhere else. I wanna write my own ArrayList class to code this functionality and make sure that every instantiations of ArrayList use my class. I thought about class loading mechanism to change order of classpath, but as I see java checks standard classes first.

    Read the article

  • Find the right value in recursive array

    - by fire
    I have an array with multiple sub-arrays like this: Array ( [0] => Array ( [Page_ID] => 1 [Page_Parent_ID] => 0 [Page_Title] => Overview [Page_URL] => overview [Page_Type] => content [Page_Order] => 1 ) [1] => Array ( [0] => Array ( [Page_ID] => 2 [Page_Parent_ID] => 1 [Page_Title] => Team [Page_URL] => overview/team [Page_Type] => content [Page_Order] => 1 ) ) [2] => Array ( [Page_ID] => 3 [Page_Parent_ID] => 0 [Page_Title] => Funds [Page_URL] => funds [Page_Type] => content [Page_Order] => 2 ) [3] => Array ( [0] => Array ( [Page_ID] => 4 [Page_Parent_ID] => 3 [Page_Title] => Strategy [Page_URL] => funds/strategy [Page_Type] => content [Page_Order] => 1 ) [1] => Array ( [0] => Array ( [Page_ID] => 7 [Page_Parent_ID] => 4 [Page_Title] => A Class Fund [Page_URL] => funds/strategy/a-class-fund [Page_Type] => content [Page_Order] => 1 ) [1] => Array ( [0] => Array ( [Page_ID] => 10 [Page_Parent_ID] => 7 [Page_Title] => Information [Page_URL] => funds/strategy/a-class-fund/information [Page_Type] => content [Page_Order] => 1 ) [1] => Array ( [Page_ID] => 11 [Page_Parent_ID] => 7 [Page_Title] => Fund Data [Page_URL] => funds/strategy/a-class-fund/fund-data [Page_Type] => content [Page_Order] => 2 ) ) [2] => Array ( [Page_ID] => 8 [Page_Parent_ID] => 4 [Page_Title] => B Class Fund [Page_URL] => funds/strategy/b-class-fund [Page_Type] => content [Page_Order] => 2 ) I need a function to find the right Page_URL so if you know the $url is "funds/strategy/a-class-fund" I need to pass that to a function that returns a single array result (which would be the Page_ID = 7 array in this example). Having a bit of a stupid day, any help would be appreciated!

    Read the article

  • How can I specify dependencies in the manifest file and then to include it into my .jar file?

    - by Roman
    I generated .class files by the following command: javac -cp \directoryName\external.jar myPackageDirectory\First.java myPackageDirectory\Second.java I needed to use -cp during compilation and name of .jar file of an "external" library (external.jar) to be able to use this library from my code. Using my .class files I have generated my .jar file in the following way: jar cfm app.jar manifest.txt myPackageDirectory\*.class manifest.txt contains just one line: Main-Class: myPackageName.First My problem is that I am not sure that I will be able to run my .jar file on other computers. I think so because during the compilation I specified the location of the .jar file of the external library. So, my .class files (included into the .jar file will try to find the .jar file of the external library in a specific directory and there is no guaranty that that the .jar file of the external library will be in the same directory as on the my computer. I heard that the above problem can be solved by a usage of a MANIFEST file that I include in my own jar, and which will list dependency locations but I do not understand how it works. I do need to specify location of the "external.jar" at the compilation stage (otherwise the compiler complains).

    Read the article

  • avoiding enums as interface identifiers c++ OOP

    - by AlasdairC
    Hi I'm working on a plugin framework using dynamic loaded shared libraries which is based on Eclipse's (and probally other's) extension-point model. All plugins share similar properties (name, id, version etc) and each plugin could in theory satisfy any extension-point. The actual plugin (ie Dll) handling is managed by another library, all I am doing really is managing collections of interfaces for the application. I started by using an enum PluginType to distinguish the different interfaces, but I have quickly realised that using template functions made the code far cleaner and would leave the grunt work up to the compiler, rather than forcing me to use lots of switch {...} statements. The only issue is where I need to specify like functionality for class members - most obvious example is the default plugin which provides a particular interface. A Settings class handles all settings, including the default plugin for an interface. ie Skin newSkin = settings.GetDefault<ISkin>(); How do I store the default ISkin in a container without resorting to some other means of identifying the interface? As I mentioned above, I currently use a std::map<PluginType, IPlugin> Settings::defaults member to achieve this (where IPlugin is an abstract base class which all plugins derive from. I can then dynamic_cast to the desired interface when required, but this really smells of bad design to me and introduces more harm than good I think. would welcome any tips edit: here's an example of the current use of default plugins typedef boost::shared_ptr<ISkin> Skin; typedef boost::shared_ptr<IPlugin> Plugin; enum PluginType { skin, ..., ... } class Settings { public: void SetDefault(const PluginType type, boost::shared_ptr<IPlugin> plugin) { m_default[type] = plugin; } boost::shared_ptr<IPlugin> GetDefault(const PluginType type) { return m_default[type]; } private: std::map<PluginType, boost::shared_ptr<IPlugin> m_default; }; SkinManager::Initialize() { Plugin thedefault = g_settings.GetDefault(skinplugin); Skin defaultskin = boost::dynamic_pointer_cast<ISkin>(theskin); defaultskin->Initialize(); } I would much rather call the getdefault as the following, with automatic casting to the derived class. However I need to specialize for every class type. template<> Skin Settings::GetDefault<ISkin>() { return boost::dynamic_pointer_cast<ISkin>(m_default(skin)); }

    Read the article

  • help me to choose between two designs

    - by alex
    // stupid title, but I could not think anything smarter I have a code (see below, sorry for long code but it's very-very simple): namespace Option1 { class AuxClass1 { string _field1; public string Field1 { get { return _field1; } set { _field1 = value; } } // another fields. maybe many fields maybe several properties public void Method1() { // some action } public void Method2() { // some action 2 } } class MainClass { AuxClass1 _auxClass; public AuxClass1 AuxClass { get { return _auxClass; } set { _auxClass = value; } } public MainClass() { _auxClass = new AuxClass1(); } } } namespace Option2 { class AuxClass1 { string _field1; public string Field1 { get { return _field1; } set { _field1 = value; } } // another fields. maybe many fields maybe several properties public void Method1() { // some action } public void Method2() { // some action 2 } } class MainClass { AuxClass1 _auxClass; public string Field1 { get { return _auxClass.Field1; } set { _auxClass.Field1 = value; } } public void Method1() { _auxClass.Method1(); } public void Method2() { _auxClass.Method2(); } public MainClass() { _auxClass = new AuxClass1(); } } } class Program { static void Main(string[] args) { // Option1 Option1.MainClass mainClass1 = new Option1.MainClass(); mainClass1.AuxClass.Field1 = "string1"; mainClass1.AuxClass.Method1(); mainClass1.AuxClass.Method2(); // Option2 Option2.MainClass mainClass2 = new Option2.MainClass(); mainClass2.Field1 = "string2"; mainClass2.Method1(); mainClass2.Method2(); Console.ReadKey(); } } What option (option1 or option2) do you prefer ? In which cases should I use option1 or option2 ? Is there any special name for option1 or option2 (composition, aggregation) ?

    Read the article

  • Undefined behaviour with non-virtual destructors - is it a real-world issue?

    - by Roddy
    Consider the following code: class A { public: A() {} ~A() {} }; class B: public A { B() {} ~B() {} }; A* b = new B; delete b; // undefined behaviour My understanding is that the C++ standard says that deleting b is undefined behaviour - ie, anything could happen. But, in the real world, my experience is that ~A() is always invoked, and the memory is correctly freed. if B introduces any class members with their own destructors, they won't get invoked, but I'm only interested in the simple kind of case above, where inheritance is used maybe to fix a bug in one class method for which source code is unavailable. Obviously this isn't going to be what you want in non-trivial cases, but it is at least consistent. Are you aware of any C++ implementation where the above does NOT happen, for the code shown?

    Read the article

  • Dynamic swappable Data Access Layer

    - by Andy
    I'm writing a data driven WPF client. The client will typically pull data from a WCF service, which queries a SQL db, but I'd like the option to pull the data directly from SQL or other arbitrary data sources. I've come up with this design and would like to hear your opinion on whether it is the best design. First, we have some data object we'd like to extract from SQL. // The Data Object with a single property public class Customer { private string m_Name = string.Empty; public string Name { get { return m_Name; } set { m_Name = value;} } } Then I plan on using an interface which all data access layers should implement. Suppose one could also use an abstract class. Thoughts? // The interface with a single method interface ICustomerFacade { List<Customer> GetAll(); } One can create a SQL implementation. // Sql Implementation public class SqlCustomrFacade : ICustomerFacade { public List<Customer> GetAll() { // Query SQL db and return something useful // ... return new List<Customer>(); } } We can also create a WCF implementation. The problem with WCF is is that it doesn't use the same data object. It creates its own local version, so we would have to copy the details over somehow. I suppose one could use reflection to copy the values of similar fields across. Thoughts? // Wcf Implementation public class WcfCustomrFacade : ICustomerFacade { public List<Customer> GetAll() { // Get date from the Wcf Service (not defined here) List<WcfService.Customer> wcfCustomers = wcfService.GetAllCustomers(); // The list we're going to return List<Customer> customers = new List<Customer>(); // This is horrible foreach(WcfService.Customer wcfCustomer in wcfCustomers) { Customer customer = new Customer(); customer.Name = wcfCustomer.Name; customers.Add(customer); } return customers; } } I also plan on using a factory to decide which facade to use. // Factory pattern public class FacadeFactory() { public static ICustomerFacade CreateCustomerFacade() { // Determine the facade to use if (ConfigurationManager.AppSettings["DAL"] == "Sql") return new SqlCustomrFacade(); else return new WcfCustomrFacade(); } } This is how the DAL would typically be used. // Test application public class MyApp { public static void Main() { ICustomerFacade cf = FacadeFactory.CreateCustomerFacade(); cf.GetAll(); } } I appreciate your thoughts and time.

    Read the article

  • How can I tell if an ADODB::_RecordsetPtr has already been created?

    - by scottm
    I am trying to write a class that uses ADO to retrieve SQL records. The intent is for the class to maintain one private recordset an other methods move forward, retrieve fields, etc. This is a basic example of my class: class SqlADO { private: ADODB::_RecordsetPtr m_recordset; public: void Open(); //open the connection void Execute(const char* sql); // creates or replaces current recordset void Next(); //moves recordset cursor forward void Field(const char* fieldName); //retrieves field name from current record of the recordset }; My Questions: In the Execute method, how can I check to see that the recordset instance has been created (or do I need to) so that I can close it first? Do you know of any good ADO COM Interop references?

    Read the article

  • Fortran pointer as an argument to interface procedure

    - by icarusthecow
    Im trying to use interfaces to call different subroutines with different types, however, it doesnt seem to work when i use the pointer attribute. for example, take this sample code MODULE ptr_types TYPE, abstract :: parent INTEGER :: q END TYPE TYPE, extends(parent) :: child INTEGER :: m END TYPE INTERFACE ptr_interface MODULE PROCEDURE do_something END INTERFACE CONTAINS SUBROUTINE do_something(atype) CLASS(parent), POINTER :: atype ! code determines that this allocation is correct from input ALLOCATE(child::atype) WRITE (*,*) atype%q END SUBROUTINE END MODULE PROGRAM testpass USE ptr_types CLASS(child), POINTER :: ctype CALL ptr_interface(ctype) END PROGRAM This gives error Error: There is no specific subroutine for the generic 'ptr_interface' at (1) however if i remove the pointer attribute in the subroutine it compiles fine. Now, normally this wouldnt be a problem, but for my use case i need to be able to treat that argument as a pointer, mainly so i can allocate it if necessary. Any suggestions? Mind you I'm new to fortran so I may have missed something edit: forgot to put the allocation in the parents subroutine, the initial input is unallocated EDIT 2 this is my second attempt, with caller side casting MODULE ptr_types TYPE, abstract :: parent INTEGER :: q END TYPE TYPE, extends(parent) :: child INTEGER :: m END TYPE TYPE, extends(parent) :: second INTEGER :: meow END TYPE CONTAINS SUBROUTINE do_something(this, type_num) CLASS(parent), POINTER :: this INTEGER type_num IF (type_num == 0) THEN ALLOCATE (child::this) ELSE IF (type_num == 1) THEN ALLOCATE (second::this) ENDIF END SUBROUTINE END MODULE PROGRAM testpass USE ptr_types CLASS(child), POINTER :: ctype SELECT TYPE(ctype) CLASS is (parent) CALL do_something(ctype, 0) END SELECT WRITE (*,*) ctype%q END PROGRAM however this still fails. in the select statement it complains that parent must extend child. Im sure this is due to restrictions when dealing with the pointer attribute, for type safety, however, im looking for a way to convert a pointer into its parent type for generic allocation. Rather than have to write separate allocation functions for every type and hope they dont collide in an interface or something. hopefully this example will illustrate a little more clearly what im trying to achieve, if you know a better way let me know

    Read the article

  • What's my best approach on this simple hierarchy Java Problem?

    - by Nazgulled
    First, I'm sorry for the question title but I can't think of a better one to describe my problem. Feel free to change it :) Let's say I have this abstract class Box which implements a couple of constructors, methods and whatever on some private variables. Then I have a couple of sub classes like BoxA and BoxB. Both of these implement extra things. Now I have another abstract class Shape and a few sub classes like Square and Circle. For both BoxA and BoxB I need to have a list of Shape objects but I need to make sure that only Square objects go into BoxA's list and only Circle objects go into BoxB's list. For that list (on each box), I need to have a get() and set() method and also a addShape() and removeShape() methods. Another important thing to know is that for each box created, either BoxA or BoxB, each respectively Shape list is exactly the same. Let's say I create a list of Square's named ls and two BoxA objects named boxA1 and boxA2. No matter what, both boxA1 and boxA2 must have the same ls list. This is my idea: public abstract class Box { // private instance variables public Box() { // constructor stuff } // public instance methods } public class BoxA extends Box { // private instance variables private static List<Shape> list; public BoxA() { // constructor stuff } // public instance methods public static List<Square> getList() { List<Square> aux = new ArrayList<Square>(); for(Square s : list.values()) { aux.add(s.clone()); // I know what I'm doing with this clone, don't worry about it } return aux; } public static void setList(List<Square> newList) { list = new ArrayList<Square>(newList); } public static void addShape(Square s) { list.add(s); } public static void removeShape(Square s) { list.remove(list.indexOf(s)); } } As the list needs to be the same for that type of object, I declared as static and all methods that work with that list are also static. Now, for BoxB the class would be almost the same regarding the list stuff. I would only replace Square by Triangle and the problem was solved. So, for each BoxA object created, the list would be only one and the same for each BoxB object created, but a different type of list of course. So, what's my problem you ask? Well, I don't like the code... The getList(), setList(), addShape() and removeShape() methods are basically repeated for BoxA and BoxB, only the type of the objects that the list will hold is different. I can't think of way to do it in the super class Box instead. Doing it statically too, using Shape instead of Square and Triangle, wouldn't work because the list would be only one and I need it to be only one but for each sub class of Box. How could I do this differently and better? P.S: I could not describe my real example because I don't know the correct words in English for the stuff I'm doing, so I just used a box and shapes example, but it's basically the same.

    Read the article

< Previous Page | 458 459 460 461 462 463 464 465 466 467 468 469  | Next Page >