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• How can I share Configuration Settings across multiple projects in Visual Studio?

  - by Muneeb

  Ok I know this may be a design issue, so I would love to have remarks on that as well. I have a Visual Studio web application solution. I have three projects as UserInterface, BusinessLogic and DataAccess. I had to store some user defined settings and I created configSections in the config file. I access these configSections through classes which inherit from .NET's ConfigurationSection base class. So in short for every project I had a separate configSection and for that corresponding configSection I had a class in that project inheriting from ConfigurationSection to access the config section settings. This works all sweet. But the problem arises if there is any setting which I need to use across multiple projects. So If I need to use a setting defined in UserInterface project configSection in, let say, BusinessLogic project I have to actually make a copy of that setting in the BusinessLogic's configSection. This ends up having the same setting copied across multiple configSections. Isn't this a bit too redundant?

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• Class hierarchy problem (with generic's variance!)

  - by devoured elysium

  The problem: class StatesChain : IState, IHasStateList { private TasksChain tasks = new TasksChain(); ... public IList<IState> States { get { return _taskChain.Tasks; } } IList<ITask> IHasTasksCollection.Tasks { get { return _taskChain.Tasks; } <-- ERROR! You can't do this in C#! I want to return an IList<ITask> from an IList<IStates>. } } Assuming the IList returned will be read-only, I know that what I'm trying to achieve is safe (or is it not?). Is there any way I can accomplish what I'm trying? I wouldn't want to try to implement myself the TasksChain algorithm (again!), as it would be error prone and would lead to code duplication. Maybe I could just define an abstract Chain and then implement both TasksChain and StatesChain from there? Or maybe implementing a Chain<T> class? How would you approach this situation? The Details: I have defined an ITask interface: public interface ITask { bool Run(); ITask FailureTask { get; } } and a IState interface that inherits from ITask: public interface IState : ITask { IState FailureState { get; } } I have also defined an IHasTasksList interface: interface IHasTasksList { List<Tasks> Tasks { get; } } and an IHasStatesList: interface IHasTasksList { List<Tasks> States { get; } } Now, I have defined a TasksChain, that is a class that has some code logic that will manipulate a chain of tasks (beware that TasksChain is itself a kind of ITask!): class TasksChain : ITask, IHasTasksList { IList<ITask> tasks = new List<ITask>(); ... public List<ITask> Tasks { get { return _tasks; } } ... } I am implementing a State the following way: public class State : IState { private readonly TaskChain _taskChain = new TaskChain(); public State(Precondition precondition, Execution execution) { _taskChain.Tasks.Add(precondition); _taskChain.Tasks.Add(execution); } public bool Run() { return _taskChain.Run(); } public IState FailureState { get { return (IState)_taskChain.Tasks[0].FailureTask; } } ITask ITask.FailureTask { get { return FailureState; } } } which, as you can see, makes use of explicit interface implementations to "hide" FailureTask and instead show FailureState property. The problem comes from the fact that I also want to define a StatesChain, that inherits both from IState and IHasStateList (and that also imples ITask and IHasTaskList, implemented as explicit interfaces) and I want it to also hide IHasTaskList's Tasks and only show IHasStateList's States. (What is contained in "The problem" section should really be after this, but I thought puting it first would be way more reader friendly). (pff..long text) Thanks!

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• Java synchronized method lock on object, or method?

  - by wuntee

  If I have 2 synchronized methods in the same class, but each accessing different variables, can 2 threads access those 2 methods at the same time? Does the lock occur on the object, or does it get as specific as the variables inside the synchronized method? Example: class x{ private int a; private int b; public synchronized void addA(){ a++; } public synchronized void addB(){ b++; } } Can 2 threads access the same instance of class x performing x.addA() and x.addB() at the same time?

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• What's the standard way to organize the contents of Java packages -- specifically the location of in

  - by RenderIn

  I suppose this could go for many OO languages. I'm building my domain objects and am not sure where the best place is for the interfaces & abstract classes. If I have a pets package with various implementations of the APet abstract class: should it live side-by-side with them or in the parent package? How about interfaces? It seems like they almost have to live above the implementations in the parent package, since there could potentially be other subpackages which implement it, while there seems to be a stronger correlation between one abstract class and a subpackage. e.g. com.foo com.foo.IConsumer (interface) com.foo.APet (abstract) com.foo.pets.Dog extends APet implements IConsumer OR com.foo com.foo.IConsumer (interface) com.foo.pets.APet (abstract) com.foo.pets.Dog extends APet implements IConsumer or something else?

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• Resources to learn about engineering aspects of data analytics (OLAP, warehousing, ETL, etc.)

  - by JT

  I'm a math/stats guy, interested in learning more about the engineering aspects of "data analytics" (this may be an overly broad term, this is a case of "I don't know what I don't know", so I'm not sure how to be more specific). I'm fine with manipulating and analyzing the data once it's already stored somewhere and I can access it, and I'm fine with writing scripts and SQL queries (and have a general knowledge of things like normalization). What I don't know is the whole engineering process of capturing and storing the data. For example, terms I've heard thrown about that I only vaguely understand the meaning of include: - OLAP, OLTP - Data warehousing - ETL - ??? What's a good book (or any other resource) to learn about these kinds of things? What are things I should know about database design (normalization seems kinda "obvious" to me, something I would have done even before I knew the term -- is there anything else?)? In other words, for jobs falling under the umbrella term of "analytics engineer", what kinds of things should I know?

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• Separate functionality depending on Role in ASP.NET MVC

  - by Andrew Bullock

  I'm looking for an elegant pattern to solve this problem: I have several user roles in my system, and for many of my controller actions, I need to deal with slightly different data. For example, take /Users/Edit/1 This allows a Moderator to edit a users email address, but Administrators to edit a user's email address and password. I'd like a design for separating the two different bits of action code for the GET and the POST. Solutions I've come up with so far are: Switch inside each method, however this doesn't really help when i want different model arguments on the POST :( Custom controller factory which chooses a UsersController_ForModerators and UsersController_ForAdmins instead of just UsersController from the controller name and current user role Custom action invoker which choose the Edit_ForModerators method in a similar way to above Have an IUsersController and register a different implementation of it in my IoC container as a named instance based on Role Build an implementation of the controller at runtime using Castle DynamicProxy and manipulate the methods to those from role-based implementations Im preferring the named IoC instance route atm as it means all my urls/routing will work seamlessly. Ideas? Suggestions?

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• Fatal error: Function name must be a string in.. PHP error

  - by Jonesy

  Hi I have a class called User and a method called insertUser(). function insertUser($first_name, $last_name, $user_name, $password, $email_address, $group_house_id) { $first_name = mysql_real_escape_string($first_name); $last_name = mysql_real_escape_string($last_name); $user_name = mysql_real_escape_string($user_name); $password = mysql_real_escape_string($password); $email_address = mysql_real_escape_string($email_address); $query = "INSERT INTO Users (FirstName,LastName,UserName,Password,EmailAddress, GroupHouseID) VALUES ('$first_name','$last_name','$user_name','$password','$email_address','$group_house_id')"; $mysql_query($query); } And I call it like this: $newUser = new User(); $newUser->insertUser($first_name, $last_name, $user_name, $email, $password, $group_house_id); When I run the code I get this error: Fatal error: Function name must be a string in /Library/WebServer/Documents/ORIOnline/includes/class_lib.php on line 33 Anyone know what I am doing wronly? Also, this is my first attempt at OO PHP. Cheers, Jonesy

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• Function Object in Java .

  - by Tony

  I wanna implement a javascript like method in java , is this possible ? Say , I have a Person class : public class Person { private String name ; private int age ; // constructor ,accessors are omitted } And a list with Person objects: Person p1 = new Person("Jenny",20); Person p2 = new Person("Kate",22); List<Person> pList = Arrays.asList(new Person[] {p1,p2}); I wanna implement a method like this: modList(pList,new Operation (Person p) { incrementAge(Person p) { p.setAge(p.getAge() + 1)}; }); modList receives two params , one is a list , the other is the "Function object", it loops the list ,and apply this function to every element in the list. In functional programming language,this is easy , I don't know how java do this? Maybe could be done through dynamic proxy, does that have a performance trade off?

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• What is a flexible, hybrid python collection object?

  - by Naveen

  As a way to get used to python, I am trying to translate some of my code to python from Autohotkey_L. I am immediately running into tons of choices for collection objects. Can you help me figure out a built in type or a 3rd party contributed type that has as much as possible, the functionality of the AutoHotkey_L object type and its methods. AutoHotkey_L Objects have features of a python dict, list, and a class instance. I understand that there are tradeoffs for space and speed, but I am just interested in functionality rather than optimization issues.

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• What is the difference between MVC model 1 and model 2?

  - by Alex Ciminian

  I've recently discovered that MVC is supposed to have two different flavors, model one and model two. I'm supposed to give a presentation on MVC1 and I was instructed that "it's not the web based version, that is refered to as MVC2". As the presentations are about design patterns in general, I doubt that this separation is related to Java (I found some info on Sun's site, but it seemed far off) or ASP. I have a pretty good understanding of what MVC is and I've used several (web) frameworks that enforce it, but this terminology is new to me. How is the web-based version different from other MVC (I'm guessing GUI) implementations? Does it have something to do with the stateless nature of HTTP? Thanks, Alex

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• add method to reflection-object and named-scopes

  - by toy

  I Like to add a method to my has_many relation in the way that it is applyed on the relation object. I got an Order wich :has_many line_items I like to write things like order.line_items.calculate_total # returns the sum of line_items this I could do with: :has_many line_items do def calculate_total ... end end but this would not be applyed to named_scopes like payalbes_only: order.line_items.payables_only.calculate_total here calculate total would receive all line_items of order and not the scoped ones from payables_only-scope. My log tells me that the paybles_only scope is even not applied to the sql.

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• Using inheritance and polymorphism to solve a common game problem

  - by Barry Brown

  I have two classes; let's call them Ogre and Wizard. (All fields are public to make the example easier to type in.) public class Ogre { int weight; int height; int axeLength; } public class Wizard { int age; int IQ; int height; } In each class I can create a method called, say, battle() that will determine who will win if an Ogre meets and Ogre or a Wizard meets a Wizard. Here's an example. If an Ogre meets an Ogre, the heavier one wins. But if the weight is the same, the one with the longer axe wins. public Ogre battle(Ogre o) { if (this.height > o.height) return this; else if (this.height < o.height) return o; else if (this.axeLength > o.axeLength) return this; else if (this.axeLength < o.axeLength) return o; else return this; // default case } We can make a similar method for Wizards. But what if a Wizard meets an Ogre? We could of course make a method for that, comparing, say, just the heights. public Wizard battle(Ogre o) { if (this.height > o.height) return this; else if (this.height < o.height) return o; else return this; } And we'd make a similar one for Ogres that meet Wizard. But things get out of hand if we have to add more character types to the program. This is where I get stuck. One obvious solution is to create a Character class with the common traits. Ogre and Wizard inherit from the Character and extend it to include the other traits that define each one. public class Character { int height; public Character battle(Character c) { if (this.height > c.height) return this; else if (this.height < c.height) return c; else return this; } } Is there a better way to organize the classes? I've looked at the strategy pattern and the mediator pattern, but I'm not sure how either of them (if any) could help here. My goal is to reach some kind of common battle method, so that if an Ogre meets an Ogre it uses the Ogre-vs-Ogre battle, but if an Ogre meets a Wizard, it uses a more generic one. Further, what if the characters that meet share no common traits? How can we decide who wins a battle?

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• Accessing a Class Member from a First-Class Function

  - by dbyrne

  I have a case class which takes a list of functions: case class A(q:Double, r:Double, s:Double, l:List[(Double)=>Double]) I have over 20 functions defined. Some of these functions have their own parameters, and some of them also use the q, r, and s values from the case class. Two examples are: def f1(w:Double) = (d:Double) => math.sin(d) * w def f2(w:Double, q:Double) = (d:Double) => d * q * w The problem is that I then need to reference q, r, and s twice when instantiating the case class: A(0.5, 1.0, 2.0, List(f1(3.0), f2(4.0, 0.5))) //0.5 is referenced twice I would like to be able to instantiate the class like this: A(0.5, 1.0, 2.0, List(f1(3.0), f2(4.0))) //f2 already knows about q! What is the best technique to accomplish this? Can I define my functions in a trait that the case class extends? EDIT: The real world application has 7 members, not 3. Only a small number of the functions need access to the members. Most of the functions don't care about them.

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• creational pattern for instances depending on multiple subclass instances

  - by markusw

  I have a problem, for that I was not able to identify a suitable design pattern. I want to create instances depending on a given type that has been passed to a factory method. What I am doing until now is the following: T create(SuperType x) { if (x instanceof SubType1) { // do some stuff and return a new SubType extends T } else if (x instanceof SubType2) { // do some stuff and return a new SubType extends T } else if ... } else { throw new UnSupportedOperationException("nothing defined for " + x); } } It seems not to be best pratice for me. Has anybody an idea how to solve this in a better way?

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• javascript: execute a bunch of asynchronous method with one callback

  - by Samuel Michelot

  I need to execute a bunch of asynchronous methods (client SQLite database), and call only one final callback. Of course, the ugly way is: execAll : function(callBack) { asynch1(function() { asynch2(function() { ... asynchN(function() { callBack(); }) }) }); } But I know there are better ways to do it. Intuitively I would detect when all call back has been called with a counter to call the final callback. I think this is a common design-pattern, so if someone could point me in the right direction... Thanks in advance !

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• Order SimpleXMLElement by element

  - by ron

  Hi everyone I need to order a SimpleXMLElement by a node called padre like this. $xml = new SimpleXMLElement('sitemap.xml',null,true); sort($xml, "padre" ); foreach($xml as $url ) { echo "loc}' title='".rescue_name($url-loc)."'".rescue_name($url-loc)." {$url-padre}"; } I don't know why is not working please let me know what is my error. Thanks in advance

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• One executable with cmd-line params or just many satellite executables?

  - by Nikos Baxevanis

  I design an application back-end. For now, it is a .NET process (a Console Application) which hosts various communication frameworks such as Agatha and NServiceBus. I need to periodically update my datastore with values (coming from the application while it's running). I found three possible ways: Accept command line arguments, so I can call my console app with -update. On start up a background thread will periodically invoke the update method. Create an updater.exe app which will do the updates, but I will have code duplication since in some way it will need to query the data from the source in order to save it to the datastore. Which one is better?

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• JSTL param implicit object

  - by srinannapa

  Hi , i'm using struts 2 and jstl. facing problem with param implicit object. Here is the test code : <% request.setAttribute ("error", "Failed"); %> <%= request.getAttribute("error") %> ----------> Prints "Failed" <c:out value="${param.error}"></c:out> ---------> Prints nothing?? Why param.error is not producing the result.

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• Database layout tagging system

  - by Kurresmack

  I am creating a web site for a customer and they want to be able to create articles. My idea is to tag them so I am going to implement the system. What is the best design, both from an architectural and a perfomance perspective: 1. To have table with all tags and then have a one to many relationship table that links a tag like this: articles table with ID tags table with ID one to many table with columns Article.ID and Tags.ID 2. To have one table with articles and one with tags for articles like this: articles table with ID tags table with Article.ID and tag text Thanks in advance!

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• Application Composer Series: Where and When to use Groovy

  - by Richard Bingham

  This brief post is really intended as more of a reference than an article. The table below highlights two things, firstly where you can add you own custom logic via groovy code (end column), and secondly (middle column) when you might use each particular feature. Obviously this applies only where Application Composer exists, namely Fusion CRM and Oracle Sales Cloud, and is based on current (release 8) functionality. Feature Most Common Use Case Groovy Field Triggers React to run-time data changes. Only fired when the field is changed and upon submit. Y Object Triggers To extend the standard processing logic for an object, based on record creation, updates and deletes. There is a split between these firing events, with some related to UI/ADF actions and others originating in the database. UI Trigger Points: After Create - fires when a new object record is created. Commonly used to set default values for fields. Before Modify - Fires when the end-user tries to modify a field value. Could be used for generic warnings or extra security logic. Before Invalidate - Fires on the parent object when one of its child object records is created, updated, or deleted. For building in relationship logic. Before Remove - Fires when an attempt is made to delete an object record. Can be used to create conditions that prevent deletes. Database Trigger Points: Before Insert in Database - Fires before a new object is inserted into the database. Can be used to ensure a dependent record exists or check for duplicates. After Insert in Database - Fires after a new object is inserted into the database. Could be used to create a complementary record. Before Update in Database -Fires before an existing object is modified in the database. Could be used to check dependent record values. After Update in Database - Fires after an existing object is modified in the database. Could be used to update a complementary record. Before Delete in Database - Fires before an existing object is deleted from the database. Could be used to check dependent record values. After Delete in Database - Fires after an existing object is deleted from the database. Could be used to remove dependent records. After Commit in Database - Fires after the change pending for the current object (insert, update, delete) is made permanent in the current transaction. Could be used when committed data that has passed all validation is required. After Changes Posted to Database - Fires after all changes have been posted to the database, but before they are permanently committed. Could be used to make additional changes that will be saved as part of the current transaction. Y Field Validation Displays a user entered error message based groovy logic validating the field value. The message is shown only when the validation logic returns false, and the logic is triggered only when tabbing out of the field on the user interface. Y Object Validation Commonly used where validation is needed across multiple related fields on the object. Triggered on the submit UI action. Y Object Workflows All Object Workflows are fired upon either record creation or update, along with the option of adding a custom groovy firing condition. Y Field Updates - change another field when a specified one changes. Intended as an easy way to set different run-time values (e.g. pick values for LOV's) plus the value field permits groovy logic entry. Y E-Mail Notification - sends an email notification to specified users/roles. Templates support using run-time value tokens and rich text. N Task Creation - for adding standard tasks for use in the worklist functionality. N Outbound Message - will create and send an XML payload of the related object SDO to a specified endpoint. N Business Process Flow - intended for approval using the seeded process, however can also trigger custom BPMN flows. N Global Functions Utility functions that can be called from any groovy code in Application Composer (across applications). Y Object Functions Utility functions that are local to the parent object. Usually triggered from within 'Buttons and Actions' definitions in Application Composer, although can be called from other code for that object (e.g. from a trigger). Y Add Custom Fields When adding custom fields there are a few places you can include groovy logic. Y Default Value - to add logic within setting the default value when new records are entered. Y Conditionally Updateable - to add logic to set the field to read-only or not. Y Conditionally Required - to add logic to set the field to required or not. Y Formula Field - Used to provide a new aggregate field that is entirely based on groovy logic and other field values. Y Simplified UI Layouts - Advanced Expressions Used for creating dynamic layouts for simplified UI pages where fields and regions show/hide based on run-time context values and logic. Also includes support for the depends-on feature as a trigger. Y Related References This Blog: Application Composer Series Extending Sales Guide: Using Groovy Scripts Groovy Scripting Reference Guide

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• Better to use constructor or method factory pattern?

  - by devoured elysium

  I have a wrapper class for the Bitmap .NET class called BitmapZone. Assuming we have a WIDTH x HEIGHT bitmap picture, this wrapper class should serve the purpose of allowing me to send to other methods/classes itself instead of the original bitmap. I can then better control what the user is or not allowed to do with the picture (and I don't have to copy the bitmap lots of times to send for each method/class). My question is: knowing that all BitmapZone's are created from a Bitmap, what do you find preferrable? Constructor syntax: something like BitmapZone bitmapZone = new BitmapZone(originalBitmap, x, y, width, height); Factory Method Pattern: BitmapZone bitmapZone = BitmapZone.From(originalBitmap, x , y, width, height); Factory Method Pattern: BitmapZone bitmapZone = BitmapZone.FromBitmap(originalBitmap, x, y, width, height); Other? Why? Thanks

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• Class Methods Inheritence

  - by Roman A. Taycher

  I was told that static methods in java didn't have Inheritance but when I try the following test package test1; public class Main { /** * @param args the command line arguments */ public static void main(String[] args) { TB.ttt(); TB.ttt2(); } } package test1; public class TA { static public Boolean ttt() { System.out.println("TestInheritenceA"); return true; } static public String test ="ClassA"; } package test1; public class TB extends TA{ static public void ttt2(){ System.out.println(test); } } it printed : TestInheritenceA ClassA so do java static methods (and fields have) inheritance (if you try to call a class method does it go down the inheritance chai looking for class methods). Was this ever not the case,are there any inheritance OO languages that are messed up like that for class methods?

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• Object does not support this propery or method IE & jQuery

  - by Mirko

  I am using jQuery and the cornerz plug in to get rounded corners on elements of the page without using images. In IE7 and 8 it fails and I get this error: "Object doesn't support this property or method" on this lines: if($.browser.msie && settings.fixIE) { var ow = $$.outerWidth(); var oh = $$.outerHeight(); Basically it complains about the outerWidth and outerHeight properties... The cornerz demo page (here) works perfectly on IE7 and 8 without throwing any error and it has got several examples...I do not know why this is happening Any suggestion will be appreciated Thanks in advance

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• Is there a standard practice for storing default application data?

  - by Rox Wen

  Our application includes a default set of data. The default data includes coefficients and other factors that are unlikely to ever change but still need to be update-able by the user. Currently, the original default data is stored as a populated class within the application. Data updates are stored to an external XML file. This design allows us to include a "reset" feature to restore the original default data. Our rationale for not storing defaults externally [e.g. XML file] was to minimize the risk of being altered. The overall volume of data doesn't warrant a database. Is there a standard practice for storing "default" application data?

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• Copying a Polymorphic object in C++

  - by doron

  I have base-class Base from which is derived Derived1, Derived2 and Derived3. I have constructed an instance for one of the the derived classes which I store as Base* a. I now need to make a deep copy of the object which I will store as Base* b. As far as I know, the normal way of copying a class is to use copy constructors and to overload operator=. However since I don't know whether a is of type Derived1, Derived2 or Derived3, I cannot think of a way of using either the copy constructor or operator=. The only way I can think of to cleanly make this work is to implement something like: class Base { public: virtual Base* Clone() = 0; }; and the implement Clone in in the derived class as in: class Derivedn : public Base { public: Base* Clone() { Derived1* ret = new Derived1; copy all the data members } }; Java tends to use Clone quite a bit is there more of a C++ way of doing this?

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