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• [Smalltalk] Store List of Instruction

  - by Luciano Lorenti

  Hi all, I have a design Problem. i have a Drawer class wich invokes a serie of methods of a kind-of-brush class and i have a predefined shapes which i want to draw. Each shape uses a list of instance methods from the drawer. I can have more than 1 brush object. I want to add custom shapes on runtime in the drawer instance, especifying the list of methods of the new shape. i've created a class method for every predefined shape that returns a BlockClosure with the instruccions. Obviously i have to give to each BlockClosure the brush object as parameter. I imagine a collection with all the BlockClosures in each instance of the Drawer Class. Maybe i can inherit a SequenceableCollection and make a instruccion collection. Each element of the collection it's a instruction and i give the brush object when i instance this new collection. I really don't know the best way to store these steps. (Maybe a shared variable?)

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• Merging .net object graph

  - by Tiju John

  Hi guys, has anyone come across any scenario wherein you needed to merge one object with another object of same type, merging the complete object graph. for e.g. If i have a person object and one person object is having first name and other the last name, some way to merge both the objects into a single object. public class Person { public Int32 Id { get; set; } public string FirstName { get; set; } public string LastName { get; set; } } public class MyClass { //both instances refer to the same person, probably coming from different sources Person obj1 = new Person(); obj1.Id=1; obj1.FirstName = "Tiju"; Person obj2 = new Person(); ojb2.Id=1; obj2.LastName = "John"; //some way of merging both the object obj1.MergeObject(obj2); //?? //obj1.Id // = 1 //obj1.FirstName // = "Tiju" //obj1.LastName // = "John" } I had come across such type of requirement and I wrote an extension method to do the same. public static class ExtensionMethods { private const string Key = "Id"; public static IList MergeList(this IList source, IList target) { Dictionary itemData = new Dictionary(); //fill the dictionary for existing list string temp = null; foreach (object item in source) { temp = GetKeyOfRecord(item); if (!String.IsNullOrEmpty(temp)) itemData[temp] = item; } //if the same id exists, merge the object, otherwise add to the existing list. foreach (object item in target) { temp = GetKeyOfRecord(item); if (!String.IsNullOrEmpty(temp) && itemData.ContainsKey(temp)) itemData[temp].MergeObject(item); else source.Add(item); } return source; } private static string GetKeyOfRecord(object o) { string keyValue = null; Type pointType = o.GetType(); if (pointType != null) foreach (PropertyInfo propertyItem in pointType.GetProperties()) { if (propertyItem.Name == Key) { keyValue = (string)propertyItem.GetValue(o, null); } } return keyValue; } public static object MergeObject(this object source, object target) { if (source != null && target != null) { Type typeSource = source.GetType(); Type typeTarget = target.GetType(); //if both types are same, try to merge if (typeSource != null && typeTarget != null && typeSource.FullName == typeTarget.FullName) if (typeSource.IsClass && !typeSource.Namespace.Equals("System", StringComparison.InvariantCulture)) { PropertyInfo[] propertyList = typeSource.GetProperties(); for (int index = 0; index < propertyList.Length; index++) { Type tempPropertySourceValueType = null; object tempPropertySourceValue = null; Type tempPropertyTargetValueType = null; object tempPropertyTargetValue = null; //get rid of indexers if (propertyList[index].GetIndexParameters().Length == 0) { tempPropertySourceValue = propertyList[index].GetValue(source, null); tempPropertyTargetValue = propertyList[index].GetValue(target, null); } if (tempPropertySourceValue != null) tempPropertySourceValueType = tempPropertySourceValue.GetType(); if (tempPropertyTargetValue != null) tempPropertyTargetValueType = tempPropertyTargetValue.GetType(); //if the property is a list IList ilistSource = tempPropertySourceValue as IList; IList ilistTarget = tempPropertyTargetValue as IList; if (ilistSource != null || ilistTarget != null) { if (ilistSource != null) ilistSource.MergeList(ilistTarget); else propertyList[index].SetValue(source, ilistTarget, null); } //if the property is a Dto else if (tempPropertySourceValue != null || tempPropertyTargetValue != null) { if (tempPropertySourceValue != null) tempPropertySourceValue.MergeObject(tempPropertyTargetValue); else propertyList[index].SetValue(source, tempPropertyTargetValue, null); } } } } return source; } } However, this works when the source property is null, if target has it, it will copy that to source. IT can still be improved to merge when inconsistencies are there e.g. if FirstName="Tiju" and FirstName="John" Any commments appreciated. Thanks TJ

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• Mimic property/list changes on an object on another object

  - by soundslike

  I need to mimic changes (property/list) changes on an object and then apply it to another object to keep the structure/property the same. In essence it's like cloning etc. the biz rules require certain properties to not be applied to the other object, so I can't just clone the object otherwise this would be easy. I've already walked the source object to get INotifyPropertyChanged and IListChanged events, so I have the "source" and the args (Property or List) changed event notifications. Given that I guess I could build a reflection "hierarchy path" starting from the top level of the source object to get to the Property or List changed "source" (which could be several levels deep). Ignoring for the moment that certain object properties should not propagate to the other object, what's a way to build this "path"? Is a brute force top level down to build the "path" (and discard on the way back up if we don't hit the original changed event "source") the only way to do it? Any clever ideas on how to mimic changes from one object to another object?

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• How can I use Object Oriented Javascript to interact with HTML Objects

  - by Steve

  I am very new to object orientated javascript, with experience writing gui's in python and java. I am trying to create html tables that I can place in locations throughout a webpage. Each html table would have two css layouts that control if it is selected or not. I can write all of the interaction if I only have one table. It gets confusing when I have multiple tables. I am wondering how to place these tables throughout a blank webpage and then access the tables individually. I think I am having trouble understanding how inheritance and hierarchy works in javascript/html. NOTE: I am not asking how to make a table. I am trying to dynamically create multiple tables and place them throughout a webpage. Then access their css independently and change it (move them to different locations or change the way the look, independently of the other tables).

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• In Ruby, why does inspect() print out some kind of object id which is different from what object_id(

  - by Jian Lin

  When the p function is used to print out an object, it may give an ID, and it is different from what object_id() gives. What is the reason for the different numbers? >> a = Point.new => #<Point:0x4684abc> >> a.object_id => 36971870 >> a.__id__ => 36971870 >> "%X" % a.object_id => "234255E"

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• DB Object passing between classes singleton, static or other?

  - by Stephen

  So I'm designing a reporting system at work it's my first project written OOP and I'm stuck on the design choice for the DB class. Obviously I only want to create one instance of the DB class per-session/user and then pass it to each of the classes that need it. What I don't know it what's best practice for implementing this. Currently I have code like the following:- class db { private $user = 'USER'; private $pass = 'PASS'; private $tables = array( 'user','report', 'etc...'); function __construct(){ //SET UP CONNECTION AND TABLES } }; class report{ function __construct ($params = array(), $db, $user) { //Error checking/handling trimed //$db is the database object we created $this->db = $db; //$this->user is the user object for the logged in user $this->user = $user; $this->reportCreate(); } public function setPermission($permissionId = 1) { //Note the $this->db is this the best practise solution? $this->db->permission->find($permissionId) //Note the $this->user is this the best practise solution? $this->user->checkPermission(1) $data=array(); $this->db->reportpermission->insert($data) } };//end report I've been reading about using static classes and have just come across Singletons (though these appear to be passé already?) so what's current best practice for doing this?

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• What is Object Oriented Programming ill-suited for?

  - by LeguRi

  In Martin Fowler's book Refactoring, Fowler speaks of how when developers learn something new, they don't consider when it's inappropriate for the job: Ten years ago it was like that with objects. If someone asked me when not to use objects, it was hard to answer. [...] It was just that I didn't know what those limitations were, although I knew what the benefits were. Reading this, it occurred to me I don't know what the limitations or potential disadvantages of Object-Oriented Programming are. What are the limitations of Object Oriented Programming? When should one look at a project and think "OOP is not best suited for this"?

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• Any 3D, Isometric, RPG oriented engines?

  - by Don Quixote

  I was wondering if there are any game engines out there that are oriented towards isometric, 3D RPGs such as Diablo 3, Torchlight, Magika, etc.. Most engines I found so far are either oriented towards FPS, such as Cry Engine and UDK, or are far too generic, such as the Irrlicht engine, which will add what I think is unnecessary work on the engine instead of the game. Any chance there are any engines out there that are crafted to be more suitable for RPGs? I would prefer they be in Java, since it's more my forte, but beggars can't be choosers, so C++ is great as well! Thank you.

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• What is happening in Crockford's object creation technique?

  - by Chris Noe

  There are only 3 lines of code, and yet I'm having trouble fully grasping this: Object.create = function (o) { function F() {} F.prototype = o; return new F(); }; newObject = Object.create(oldObject); (from Prototypal Inheritance) 1) Object.create() starts out by creating an empty function called F. I'm thinking that a function is a kind of object. Where is this F object being stored? Globally I guess. 2) Next our oldObject, passed in as o, becomes the prototype of function F. Function (i.e., object) F now "inherits" from our oldObject, in the sense that name resolution will route through it. Good, but I'm curious what the default prototype is for an object, Object? Is that also true for a function-object? 3) Finally, F is instantiated and returned, becoming our newObject. Is the "new" operation strictly necessary here? Doesn't F already provide what we need, or is there a critical difference between function-objects and non-function-objects? Clearly it won't be possible to have a constructor function using this technique. What happens the next time Object.create() is called? Is global function F overwritten? Surely it is not reused, because that would alter previously configured objects. And what happens if multiple threads call Object.create(), is there any sort of synchronization to prevent race conditions on F?

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• Configurable Objects - Introduction

  - by Anthony Shorten

  One of the interesting facilities in the framework is Configurable Object functionality (it is also known as Task Optimization and also known as Cool Tools). The idea is that any implementation can create their own views of the base product objects and services and implement functionality against those new views. For example, in Oracle Utilities Customer Care and Billing, there is a Person object. That object is used to store and manage information about individuals as well as companies. In the base product you would use the Person Maintenance screen and fill in some of the screen when you wanted to register or maintain and individual as well and fill out other parts of the screen when you wanted to register or maintain a company. This can be somewhat confusing to some customers. Using Configurable Objects this can be simplified. A business object can be created that is a view of the any object. For example, you could create a Human business object which would cover the aspects of the Person object pertaining to an individual and a Company business object to cover the aspects unique to a company. Even the tag names (i.e. Field Names) in the object can be changed to be more what the implementation is familiar with. The object can also restructure the object. For example, a common identifier for an individual in the USA is the Social Security number, this value is a Person Identifier (as this varies in each country). In the new Human object you can remap the Person Identifier as a Social Security number. To define a Business Object you use a schema editor built into the browser user interface and use a mapping language to setup the business objects. An example of the language is shown below in an extract of the schema for the Human business object. As you can see there are mapping as well as formatting and other tags. This information can be built manually or using a wizard which generates the base structure for you to alter. This is all stored as meta data when saved. Once a Business object is built it can be used as basis for code, other business objects (we support inheritance), called by a screen (called a UI Map) or even as a Web Service. This is just a start with Configurable Objects as you can also create views of base services called Business Services, Service Scripts used for non-object or complex object processing (as well as other things), UI Maps used for screens and Data Areas to reuse definitions across multiple objects. Configurable Objects are powerful and I only really touched on them here. Over the next few months I hope to add lots more entries about them.

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• Qt 4.6 Adding objects and sub-objects to QWebView window object (C++ & Javascript)

  - by Cor

  I am working with Qt's QWebView, and have been finding lots of great uses for adding to the webkit window object. One thing I would like to do is nested objects... for instance: in Javascript I can... var api = new Object; api.os = new Object; api.os.foo = function(){} api.window = new Object(); api.window.bar = function(){} obviously in most cases this would be done through a more OO js-framework. This results in a tidy structure of: >>>api ------------------------------------------------------- - api Object {os=Object, more... } - os Object {} foo function() - win Object {} bar function() ------------------------------------------------------- Right now I'm able to extend the window object with all of the qtC++ methods and signals I need, but they all have 'seem' to have to be in a root child of "window". This is forcing me to write a js wrapper object to get the hierarchy that I want in the DOM. >>>api ------------------------------------------------------- - api Object {os=function, more... } - os_foo function() - win_bar function() ------------------------------------------------------- This is a pretty simplified example... I want objects for parameters, etc... Does anyone know of a way to pass an child object with the object that extends the WebFrame's window object? Here's some example code of how I'm adding the object: mainwindow.h #ifndef MAINWINDOW_H #define MAINWINDOW_H #include <QtGui/QMainWindow> #include <QWebFrame> #include "mainwindow.h" #include "happyapi.h" class QWebView; class QWebFrame; QT_BEGIN_NAMESPACE class MainWindow : public QMainWindow { Q_OBJECT public: MainWindow(QWidget *parent = 0); private slots: void attachWindowObject(); void bluesBros(); private: QWebView *view; HappyApi *api; QWebFrame *frame; }; #endif // MAINWINDOW_H mainwindow.cpp #include <QDebug> #include <QtGui> #include <QWebView> #include <QWebPage> #include "mainwindow.h" #include "happyapi.h" MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) { view = new QWebView(this); view->load(QUrl("file:///Q:/example.htm")); api = new HappyApi(this); QWebPage *page = view->page(); frame = page->mainFrame(); attachWindowObject(); connect(frame, SIGNAL(javaScriptWindowObjectCleared()), this, SLOT(attachWindowObject())); connect(api, SIGNAL(win_bar()), this, SLOT(bluesBros())); setCentralWidget(view); }; void MainWindow::attachWindowObject() { frame->addToJavaScriptWindowObject(QString("api"), api); }; void MainWindow::bluesBros() { qDebug() << "foo and bar are getting the band back together!"; }; happyapi.h #ifndef HAPPYAPI_H #define HAPPYAPI_H #include <QObject> class HappyApi : public QObject { Q_OBJECT public: HappyApi(QObject *parent); public slots: void os_foo(); signals: void win_bar(); }; #endif // HAPPYAPI_H happyapi.cpp #include <QDebug> #include "happyapi.h" HappyApi::HappyApi(QObject *parent) : QObject(parent) { }; void HappyApi::os_foo() { qDebug() << "foo called, it want's it's bar back"; }; I'm reasonably new to C++ programming (coming from a web and python background). Hopefully this example will serve to not only help other new users, but be something interesting for a more experienced c++ programmer to elaborate on. Thanks for any assistance that can be provided. :)

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• constructor function's object literal returns toString() method but no other method

  - by JohnMerlino

  I'm very confused with javascript methods defined in objects and the "this" keyword. In the below example, the toString() method is invoked when Mammal object instantiated: function Mammal(name){ this.name=name; this.toString = function(){ return '[Mammal "'+this.name+'"]'; } } var someAnimal = new Mammal('Mr. Biggles'); alert('someAnimal is '+someAnimal); Despite the fact that the toString() method is not invoked on the object someAnimal like this: alert('someAnimal is '+someAnimal.toString()); It still returns 'someAnimal is [Mammal "Mr. Biggles"]' . That doesn't make sense to me because the toString() function is not being called anywhere. Then to add even more confusion, if I change the toString() method to a method I make up such as random(): function Mammal(name){ this.name=name; this.random = function(){ return Math.floor(Math.random() * 15); } } var someAnimal = new Mammal('Mr. Biggles'); alert(someAnimal); It completely ignores the random method (despite the fact that it is defined the same way was the toString() method was) and returns: [object object] Another issue I'm having trouble understanding with inheritance is the value of "this". For example, in the below example function person(w,h){ width.width = w; width.height = h; } function man(w,h,s) { person.call(this, w, h); this.sex = s; } "this" keyword is being send to the person object clearly. However, does "this" refer to the subclass (man) or the super class (person) when the person object receives it? Thanks for clearing up any of the confusion I have with inheritance and object literals in javascript.

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• C++ include statement required if defining a map in a headerfile.

  - by Justin

  I was doing a project for computer course on programming concepts. This project was to be completed in C++ using Object Oriented designs we learned throughout the course. Anyhow, I have two files symboltable.h and symboltable.cpp. I want to use a map as the data structure so I define it in the private section of the header file. I #include <map> in the cpp file before I #include "symboltable.h". I get several errors from the compiler (MS VS 2008 Pro) when I go to debug/run the program the first of which is: Error 1 error C2146: syntax error : missing ';' before identifier 'table' c:\users\jsmith\documents\visual studio 2008\projects\project2\project2\symboltable.h 22 Project2 To fix this I had to #include <map> in the header file, which to me seems strange. Here are the relevant code files: // symboltable.h #include <map> class SymbolTable { public: SymbolTable() {} void insert(string variable, double value); double lookUp(string variable); void init(); // Added as part of the spec given in the conference area. private: map<string, double> table; // Our container for variables and their values. }; and // symboltable.cpp #include <map> #include <string> #include <iostream> using namespace std; #include "symboltable.h" void SymbolTable::insert(string variable, double value) { table[variable] = value; // Creates a new map entry, if variable name already exist it overwrites last value. } double SymbolTable::lookUp(string variable) { if(table.find(variable) == table.end()) // Search for the variable, find() returns a position, if thats the end then we didnt find it. throw exception("Error: Uninitialized variable"); else return table[variable]; } void SymbolTable::init() { table.clear(); // Clears the map, removes all elements. }

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• Implementation of a general-purpose object structure (property bag)

  - by Thomas Wanner

  We need to implement some general-purpose object structure, much like an object in dynamic languages, that would give us a possibility of creating the whole object graph on-the-fly. This class has to be serializable and somehow user friendly. So far we have made some experiments with class derived from Dictionary<string, object> using the dot notation path to store properties and collections in the object tree. We have also find an article that implements something similar, but it doesn't seem to fit completely into our picture either. Do you know about some good implementations / libraries that deal with a similar problem or do you have any (non-trivial) ideas that could help us with our own implementation ? Also, I probably have to say that we are using .NET 3.5, so we can't take advantage of the new features in .NET 4.0 like dynamic type etc. (as far as I know it's also not possible to use any subset of it in .NET 3.5 solution).

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• spl_object_hash for PHP < 5.2 (unique ID for object instances)

  - by Rowan

  I'm trying to get unique IDs for object instances in PHP 5+. The function, spl_object_hash() is available from PHP 5.2 but I'm wondering if there's a workaround for older versions. There are a couple of functions in the comments on php.net but they're not working for me. The first (simplified): function spl_object_hash($object){ if (is_object($object)){ return md5((string)$object); } return null; } does not work with native objects (such as DOMDocument), and the second: function spl_object_hash($object){ if (is_object($object)){ ob_start(); var_dump($object); $dump = ob_get_contents(); ob_end_clean(); if (preg_match('/^object\(([a-z0-9_]+)\)\#(\d)+/i', $dump, $match)) { return md5($match[1] . $match[2]); } } return null; } looks like it could be a major performance buster! Does anybody have anything up their sleeve?

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• Object Oriented Perl interface to read from and write to a socket

  - by user654967

  I need a perl client-server implementation as a wrapper for a server in C#. A perl script passes the server address and port number and an input string to a module, this module has to create the socket and send the input string to the server. The data sent has to follow ISO-8859-1 encoding. On receiving the information, the client has to first receive 3 byte, then the next 8 bytes, this has the length of the data that has to be received next.. so based on the length the client has to read the next data. each of the data that is read has to be stored in a variable and sent another module for further processing. Currently this is what my perl client looks like..which I'm sure isn't right..could someone tell me how to do this..and set me on the right direction.. sub WriteInfo { my ($addr, $port, $Input) = @_; $socket = IO::Socket::INET->new( Proto => "tcp", PeerAddr => $addr, PeerPort => $port, ); unless ($socket) { die "cannot connect to remote" } while (1) { $socket->send($Input); } } sub ReadData { while (1) { my $ExecutionResult = $socket->recv( $recv_data, 3); my $DataLength = $socket->recv( $recv_data, 8); $DataLength =~ s/^0+// ; my $decval = hex($DataLength); my $Data = $socket->recv( $recv_data, $decval); return($Data); } thanks a lot.. Archer

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• Interview question: difference between object and object-oriented languages.

  - by Bar

  My friend was asked the following question: what's the difference between object language and object-oriented language? It's a little unintelligible question. What does term «object language» correspond to? Does that mean «pure» object-oriented language, like the Wikipedia article says: Languages called "pure" OO languages, because everything in them is treated consistently as an object, from primitives such as characters and punctuation, all the way up to whole classes, prototypes, blocks, modules, etc. They were designed specifically to facilitate, even enforce, OO methods. Examples: Smalltalk, Eiffel, Ruby, JADE, VB.NET.

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• Why "object reference not set to an instance of an object" doesn't tell us which object?

  - by Saeed Neamati

  We're launching a system, and we sometimes get the famous exception NullReferenceException with the message Object reference not set to an instance of an object. However, in a method where we have almost 20 objects, having a log which says an object is null, is really of no use at all. It's like telling you, when you are the security agent of a seminar, that a man among 100 attendees is a terrorist. That's really of no use to you at all. You should get more information, if you want to detect which man is the threatening man. Likewise, if we want to remove the bug, we do need to know which object is null. Now, something has obsessed my mind for several months, and that is: Why .NET doesn't give us the name, or at least the type of the object reference, which is null?. Can't it understand the type from reflection or any other source? Also, what are the best practices to understand which object is null? Should we always test nullability of objects in these contexts manually and log the result? Is there a better way?

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• OO Design - polymorphism - how to design for handing streams of different file types

  - by Kache4

  I've little experience with advanced OO practices, and I want to design this properly as an exercise. I'm thinking of implementing the following, and I'm asking if I'm going about this the right way. I have a class PImage that holds the raw data and some information I need for an image file. Its header is currently something like this: #include <boost/filesytem.hpp> #include <vector> namespace fs = boost::filesystem; class PImage { public: PImage(const fs::path& path, const unsigned char* buffer, int bufferLen); const vector<char> data() const { return data_; } const char* rawData() const { return &data_[0]; } /*** other assorted accessors ***/ private: fs::path path_; int width_; int height_; int filesize_; vector<char> data_; } I want to fill the width_ and height_ by looking through the file's header. The trivial/inelegant solution would be to have a lot of messy control flow that identifies the type of image file (.gif, .jpg, .png, etc) and then parse the header accordingly. Instead of using vector<char> data_, I was thinking of having PImage use a class, RawImageStream data_ that inherits from vector<char>. Each type of file I plan to support would then inherit from RawImageStream, e.g. RawGifStream, RawPngStream. Each RawXYZStream would encapsulate the respective header-parsing functions, and PImage would only have to do something like height_ = data_.getHeight();. Am I thinking this through correctly? How would I create the proper RawImageStream subclass for data_ to be in the PImage ctor? Is this where I could use an object factory? Anything I'm forgetting?

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• Two objects with dependencies for each other. Is that bad?

  - by Kasper Grubbe

  Hi SO. I am learning a lot about design patterns these days. And I want to ask you about a design question that I can't find an answer to. Currently I am building a little Chat-server using sockets, with multiple Clients. Currently I have three classes. Person-class which holds information like nick, age and a Room-object. Room-class which holds information like room-name, topic and a list of Persons currently in that room. Hotel-class which have a list of Persons and a list of Rooms on the server. I have made a diagram to illustrate it (Sorry for the big size!): http://i.imgur.com/Kpq6V.png I have a list of players on the server in the Hotel-class because it would be nice to keep track of how many there are online right now (Without having to iterate through all of the rooms). The persons live in the Hotel-class because I would like to be able to search for a specific Person without searching the rooms. Is this bad design? Is there another way of achieve it? Thanks.

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• Associating an object with another object for GC clearup

  - by thecoop

  Is there any way of associating an object instance (object A) with a second object (object B) in a generalised way, so that when B gets collected A becomes eligable for collection? The same behaviour that would happen if B had an instance variable pointing to A, but without explicitly changing the class definition of B, and being able to do this in a dynamic way? The same sort of effect could be done by using the Component.Disposed event in a funky way, but I don't want to make B disposable EDIT I'm basically creating a cache of objects that are associated with a single 'root' object, and I don't want the cache to be static, as there can be lots of root objects using different caches, so lots of memory will be used up when a root object is no longer used but the cached objects are still around. So, I want a collection of cached objects to be associated with each 'root' object, without changing the root object definition. Sort of like metadata of an extra object reference attached to each root object instance. That way, each collection will get collected when the root object is collected, and not hang around like they would if a static cache was used.

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• redoing object model construction to fit with asynchronous data fetching

  - by Andrew Patterson

  I have a modeled a set of objects that correspond with some real world concepts. TradeDrug, GenericDrug, TradePackage, DrugForm Underlying the simple object model I am trying to provide is a complex medical terminology that uses numeric codes to represent relationships and concepts, all accessible via a REST service - I am trying to hide away some of that complexity with an object wrapper. To give a concrete example I can call TradeDrug d = Searcher.FindTradeDrug("Zoloft") or TradeDrug d = new TradeDrug(34) where 34 might be the code for Zoloft. This will consult a remote server to find out some details about Zoloft. I might then call GenericDrug generic = d.EquivalentGeneric() System.Out.WriteLine(generic.ActiveIngredient().Name) in order to get back the generic drug sertraline as an object (again via a background REST call to the remote server that has all these drug details), and then perhaps find its ingredient. This model works fine and is being used in some applications that involve data processing. Recently however I wanted to do a silverlight application that used and displayed these objects. The silverlight environment only allows asynchronous REST/web service calls. I have no problems with how to make the asychhronous calls - but I am having trouble with what the design should be for my object construction. Currently the constructors for my objects do some REST calls sychronously. public TradeDrug(int code) { form = restclient.FetchForm(code) name = restclient.FetchName(code) etc.. } If I have to use async 'events' or 'actions' in order to use the Silverlight web client (I know silverlight can be forced to be a synchronous client but I am interested in asychronous approaches), does anyone have an guidance or best practice for how to structure my objects. I can pass in an action callback to the constructor public TradeDrug(int code, Action<TradeDrug> constructCompleted) { } but this then allows the user to have a TradeDrug object instance before what I want to construct is actually finished. It also doesn't support an 'event' async pattern because the object doesn't exist to add the event to until it is constructed. Extending that approach might be a factory object that itself has an asynchronous interface to objects factory.GetTradeDrugAsync(code, completedaction) or with a GetTradeDrugCompleted event? Does anyone have any recommendations?

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• Oracle Technology Network Virtual Developer Day: Service Oriented Architecture (SOA)

  - by programmarketingOTN

  Register now! Oracle Technology Network Virtual Developer Day: Service Oriented Architecture (SOA) - Discover the Power of Oracle SOA Suite 11gTuesday July 12, 2011 - ?9:00 a.m. PT – 1:30 p.m. PT / 12 Noon EDT - 4:30 p.m. EDTOTN is proud to host another Virtual Developer Day, this time focusing on SOA (click here to check out on-demand version of Rich Enterprise Applications and WebLogic)  Save yourself/company some money and join us online for this hands-on virtual workshop. Through developer-focused product presentations and demonstrations delivered by Oracle product and technology experts, there is no faster or more efficient way to jumpstart your Oracle SOA suite learning.Over the course of the Virtual Developer Day, you will learn how an SOA approach can be implemented, whether starting fresh with new services or reusing existing services. Using Oracle SOA Suite 11g components, you will explore, modify, execute, and monitor an SOA composite application. Topics include SCA, BPEL process execution, adapters, business rules and more.Java and WebLogic experience not required for the presentations or demonstrations but it is a plus for the hands-on lab.Come to this event if you are    •    Exploring ways to deliver services faster    •    Integrating packaged and/or legacy applications    •    Developing service orchestration    •    Planning or starting new development projectsRegister online now for this FREE event.AGENDA - Tuesday July 12, 2011?9:00 a.m. PT – 1:30 p.m. PT / 12 Noon EDT - 4:30 p.m. PT EDT  Time  Title  9:00 AM Keynote  9:15 AM Presentation 1 Service Oriented Architecture (SOA) Overview  9:45 AM Demonstration 1 Mediator and Adapters  10:15 AM Presentation 2 BPEL Service Orchestration and Business Rules  10:45 AM Demonstration 2 BPEL Service Orchestration  11:15 AM Demonstration 3 Oracle Business Rules  11:45 AM Hands-on Lab time  1:30 PM Close Register online now for this FREE event.

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• Is a Model Driven Architecture in Language Oriented Programming (MPS) feasible at this time

  - by Steven Jeuris

  As a side project I am developing some sort of DSL where I describe a data model, and generate desired code files from it. I believe this is called Model Driven Architecture. My partial existing implementation uses C#, CodeDOM, XML and XSLT to do this manually. I discovered there already exist better environments to do this in. The one which fascinated me the most is called MPS, which follows the Language Oriented Programming paradigm. This article, written by a cofounder of JetBrains was a real eye opener for me. I truly believe LOP has a very good chance of becoming the next big programming paradigm once it has broader support. From my short experience with MPS, I noticed it is still mainly Java-oriented. My question is, how feasible is it to generate code files for other (multiple) languages instead of just Java. I don't need full language support from the start, so preferably, I need to be able to implement a language in a agile way. E.g. first support only one type, add access modifiers, ... Perhaps some other (free) environment already provides this out of the box. P.S.: I find it important to have a lot of control over the naming conventions and such of the generated code. This is one of the reasons why I started my own implementation.

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• Metric to measure object-orientedness

  - by Jono

  Is there a metric that can assist in determining the object-orientedness of a system or application? I've seen some pretty neat metrics in the .NET Reflector Add-ins codeplex project, but nothing like this yet. If such a metric doesn't exist, would it even be possible or useful? There are the 3 supposed tenets of object-oriented programming: encapsulation, inheritance, and polymorphism; a tool that ranked programs against these might be able to show areas of a C# (or similar) code base where the whole object-oriented ideal was discarded, and perhaps how many bugs are associated with that area versus the rest of the project.

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