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• Automated Java to Scala source code conversion?

  - by Alex R

  (Yes I know I can call Java code from Scala; but that is pointless; I want to DELETE the Java code, not keep it around and have to look at it and maintain it forever!) Are there any utilities out there to convert Java source to Scala source? I believe theoretically it should be possible to accomplish with minimal lossage. I have found this but it seems inactive, probably buggy/incomplete... http://sourceforge.net/projects/java2scala/ Any alternatives?

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• Immutability of big objects

  - by Malax

  Hi StackOverflow! I have some big (more than 3 fields) Objects which can and should be immutable. Every time I run into that case i tend to create constructor abominations with long parameter lists. It doesn't feel right, is hard to use and readability suffers. It is even worse if the fields are some sort of collection type like lists. A simple addSibling(S s) would ease the object creation so much but renders the object mutable. What do you guys use in such cases? I'm on Scala and Java, but i think the problem is language agnostic as long as the language is object oriented. Solutions I can think of: "Constructor abominations with long parameter lists" The Builder Pattern Thanks for your input!

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• Naming remote proxy classes

  - by Tobbe

  What are some good names for the client and server side classes that communicate over the network when implementing a remote proxy? The classes are often called stub and skelleton but I don't find those names very "intention revealing". Are there any other (better) alternatives?

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• Meta Search Engine Architecture

  - by Loki

  The question wasn't clear enough, I think; here's an updated straight to the point question: What are the common architectures used in building a meta search engine and is there any libraries available to build that type of search engine? I'm looking at building an "enterprise" type of search engine where the indexed data could be coming from proprietary (like Autonomy or a Google Box) or public search engines (like Google Web or Yahoo Web).

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• How to organize and manage multiple database credentials in application?

  - by Polaris878

  Okay, so I'm designing a stand-alone web service (using RestLET as my framework). My application is divided in to 3 layers: Data Layer (just above the database, provides APIs for connecting to/querying database, and a database object) Object layer (responsible for serialization from the data layer... provides objects which the client layer can use without worrying about database) Client layer (This layer is the RestLET web service... basically just creates objects from the object layer and fulfills webservice request) Now, for each object I create in the object layer, I want to use different credentials (so I can sandbox each object...). The object layer should not know the exact credentials (IE the login/pw/DB URL etc). What would be the best way to manage this? I'm thinking that I should have a super class Database object in my data layer... and each subclass will contain the required log-in information... this way my object layer can just go Database db = new SubDatabase(); and then continue using that database. On the client level, they would just be able to go ItemCollection items = new ItemCollection(); and have no idea/control over the database that gets connected. I'm asking this because I am trying to make my platform extensible, so that others can easily create services off of my platform. If anyone has any experience with these architectural problems or how to manage this sort of thing I'd appreciate any insight or advice... Feel free to ask questions if this is confusing. Thanks! My platform is Java, the REST framework I'm using is RestLET, my database is MySQL.

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• Linq to sql Repository pattern , Some doubts

  - by MindlessProgrammer

  I am using repository pattern with linq to sql, I am using a repository class per table. I want to know , am i doing at good/standard way, ContactRepository Contact GetByID() Contact GetAll() COntactTagRepository List<ContactTag> Get(long contactID) List<ContactTag> GetAll() List<ContactTagDetail> GetAllDetails() class ContactTagDetail { public Contact Contact {get;set;} public ContactTag COntactTag {get;set;} } When i need a contact i call method in contactrepository, same for contacttag but when i need contact and tags together i call GetDetais() in ContactTag repository its not returning the COntactTag entity generated by the orm insted its returning ContactTagDetail entity conatining both COntact and COntactTag generated by the orm, i know i can simple call GetAll in COntactTag repository and can access Contact.ContactTag but as its linq to sql it will there is no option to Deferred Load in query level, so whenever i need a entity with a related entity i create a projection class Another doubt is where i really need to right the method i can do it in both contact & ContactTag repostitory like In contact repository GetALlWithTags() or something but i am doing it in in COntactTag repository Whats your suggestions ?

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• How can I handle dynamic calculated attributes in a model in Django?

  - by bullfish

  In Django I calculate the breadcrumb (a list of fathers) for an geographical object. Since it is not going to change very often, I am thinking of pre calculating it once the object is saved or initialized. 1.) What would be better? Which solution would have a better performance? To calculate it at _init_ or to calculate it when the object is saved (the object takes about 500-2000 characters in the DB)? 2.) I tried to overwrite the _init_ or save() methods but I don't know how to use attributes of the just saved object. Accessing *args, **kwargs did not work. How can I access them? Do I have to save, access the father and then save again? 3.) If I decide to save the breadcrumb. Whats the best way to do it? I used http://www.djangosnippets.org/snippets/1694/ and have crumb = PickledObjectField(). Thats the method to calculate the attribute crumb() def _breadcrumb(self): breadcrumb = [ ] x = self while True: x = x.father try: if hasattr(x, 'country'): breadcrumb.append(x.country) elif hasattr(x, 'region'): breadcrumb.append(x.region) elif hasattr(x, 'city'): breadcrumb.append(x.city) else: break except: break breadcrumb.reverse() return breadcrumb Thats my save-Method: def save(self,*args, **kwargs): # how can I access the father ob the object? father = self.father # does obviously not work father = kwargs['father'] # does not work either # the breadcrumb gets calculated here self.crumb = self._breadcrumb(father) super(GeoObject, self).save(*args,**kwargs) Please help me out. I am working on this for days now. Thank you.

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• Calling DI Container directly in method code (MVC Actions)

  - by fearofawhackplanet

  I'm playing with DI (using Unity). I've learned how to do Constructor and Property injection. I have a static container exposed through a property in my Global.asax file (MvcApplication class). I have a need for a number of different objects in my Controller. It doesn't seem right to inject these throught the constructor, partly because of the high quantity of them, and partly because they are only needed in some Actions methods. The question is, is there anything wrong with just calling my container directly from within the Action methods? public ActionResult Foo() { IBar bar = (Bar)MvcApplication.Container.Resolve(IBar); // ... Bar uses a default constructor, I'm not actually doing any // injection here, I'm just telling my conatiner to give me Bar // when I ask for IBar so I can hide the existence of the concrete // Bar from my Controller. } This seems the simplest and most efficient way of doing things, but I've never seen an example used in this way. Is there anything wrong with this? Am I missing the concept in some way?

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• Normalizing Item Names & Synonyms

  - by RabidFire

  Consider an e-commerce application with multiple stores. Each store owner can edit the item catalog of his store. My current database schema is as follows: item_names: id | name | description | picture | common(BOOL) items: id | item_name_id | picture | price | description | picture item_synonyms: id | item_name_id | name | error(BOOL) Notes: error indicates a wrong spelling (eg. "Ericson"). description and picture of the item_names table are "globals" that can optionally be overridden by "local" description and picture fields of the items table (in case the store owner wants to supply a different picture for an item). common helps separate unique item names ("Jimmy Joe's Cheese Pizza" from "Cheese Pizza") I think the bright side of this schema is: Optimized searching & Handling Synonyms: I can query the item_names & item_synonyms tables using name LIKE %QUERY% and obtain the list of item_name_ids that need to be joined with the items table. (Examples of synonyms: "Sony Ericsson", "Sony Ericson", "X10", "X 10") Autocompletion: Again, a simple query to the item_names table. I can avoid the usage of DISTINCT and it minimizes number of variations ("Sony Ericsson Xperia™ X10", "Sony Ericsson - Xperia X10", "Xperia X10, Sony Ericsson") The down side would be: Overhead: When inserting an item, I query item_names to see if this name already exists. If not, I create a new entry. When deleting an item, I count the number of entries with the same name. If this is the only item with that name, I delete the entry from the item_names table (just to keep things clean; accounts for possible erroneous submissions). And updating is the combination of both. Weird Item Names: Store owners sometimes use sentences like "Harry Potter 1, 2 Books + CDs + Magic Hat". There's something off about having so much overhead to accommodate cases like this. This would perhaps be the prime reason I'm tempted to go for a schema like this: items: id | name | picture | price | description | picture (... with item_names and item_synonyms as utility tables that I could query) Is there a better schema you would suggested? Should item names be normalized for autocomplete? Is this probably what Facebook does for "School", "City" entries? Is the first schema or the second better/optimal for search? Thanks in advance! References: (1) Is normalizing a person's name going too far?, (2) Avoiding DISTINCT

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• Truly declarative language?

  - by gjvdkamp

  Hi all, Does anyone know of a truly declarative language? The behaviour I'm looking for is kind of what Excel does, where I can define variables and formulas, and have the formula's result change when the input changes (without having set the answer again myself) The behaviour I'm looking for is best shown with this pseudo code: X = 10 // define and assign two variables Y = 20; Z = X + Y // declare a formula that uses these two variables X = 50 // change one of the input variables ?Z // asking for Z should now give 70 (50 + 20) I've tried this in a lot of languages like F#, python, matlab etc, but every time i try this they come up with 30 instead of 70. Wich is correct from an imperative point of view, but i'm looking for a more declerative behaviour if you know what i mean. And this is just a very simple calculation. When things get more difficult it should handle stuff like recursion and memoization automagically. The code below would obviously work in C# but it's just so much code for the job, i'm looking for something a bit more to the point without all that 'technical noise' class BlaBla{ public int X {get;set;} // this used to be even worse before 3.0 public int Y {get;set;} public int Z {get{return X + Y;}} } static void main(){ BlaBla bla = new BlaBla(); bla.X = 10; bla.Y = 20; // can't define anything here bla.X = 50; // bit pointless here but I'll do it anyway. Console.Writeline(bla.Z);// 70, hurray! } This just seems like so much code, curly braces and semicolons that add nothing. Is there a language/ application (apart from Exel) that does this? Maybe I'm no doing it right in the mentioned langauges, or I've completely missed an app that does just this. I prototyped a language/ application that does this (along with some other stuff) and am thinking of productizing it. I just can't believe it's not there yet. Don't want to waste my time. Thanks in advance, Gert-Jan

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• Command Pattern vs. Visitor Pattern

  - by grefly

  Is it generally acceptable to allow a Visitor to modify state of the Receiver, or should that be a Command pattern instead?

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• Is there a way to restrict access to a public method to only a specific class in C#?

  - by Anon

  I have a class A with a public method in C#. I want to allow access to this method to only class B. Is this possible? UPDATE: This is what i'd like to do: public class Category { public int NumberOfInactiveProducts {get;} public IList<Product> Products {get;set;} public void ProcessInactiveProduct() { // do things... NumberOfInactiveProducts++; } } public class Product { public bool Inactive {get;} public Category Category {get;set;} public void SetInactive() { this.Inactive= true; Category.ProcessInactiveProduct(); } } I'd like other programmers to do: var prod = Repository.Get<Product>(id); prod.SetInactive(); I'd like to make sure they don't call ProcessInactiveProduct manually: var prod = Repository.Get<Product>(id); prod.SetInactive(); prod.Category.ProcessInactiveProduct(); I want to allow access of Category.ProcessInactiveProduct to only class Product. Other classes shouldn't be able to call Category.ProcessInactiveProduct.

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• Data Modeling Help - Do I add another table, change existing table's usage, or something else?

  - by StackOverflowNewbie

  Assume I have the following tables and relationships: Person - Id (PK) - Name A Person can have 0 or more pets: Pet - Id (PK) - PersonId (FK) - Name A person can have 0 or more attributes (e.g. age, height, weight): PersonAttribute _ Id (PK) - PersonId (FK) - Name - Value PROBLEM: I need to represent pet attributes, too. As it turns out, these pet attributes are, in most cases, identical to the attributes of a person (e.g. a pet can have an age, height, and weight too). How do I represent pet attributes? Do I create a PetAttribute table? PetAttribute Id (PK) PetId (FK) Name Value Do I change PersonAttribute to GenericAttribute and have 2 foreign keys in it - one connecting to Person, the other connecting to Pet? GenericAttribute Id (PK) PersonId (FK) PetId (FK) Name Value NOTE: if PersonId is set, then PetId is not set. If PetId is set, PersonId is not set. Do something else?

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• Events and references pattern

  - by serhio

  In a project I have the following relation between BO and GUI By e.g. G could represent a graphic with time lines, C a TimeLine curve, P - points of that curve and T the time that represents each point. Each GUI object is associated with the BO corresponding object. When T changes GUI P captures the Changed event and changes its location. So, when G should be modified, it modifies internally its objects and as result T changes, P moves and the GuiG visually changes, everything is OK. But there is an inconvenient of this architecture... BO should not be recreated, because this will breack the link between BO and GUIO. In particular, GUI P should always have the same reference of T. If in a business logic I do by e.g. P1.T = new T(this.T + 10) GUI_P1 will not move anymore, because it wait an event from the reference of former P1.T object, that does not belongs to P1 anymore. So the solution was to always modify the existing objects, not to recreate it. But here is an other inconvenient: performance. Say I have a ready newC object that should replace the older one. Instead of doing G1.C = newC I should do foreach T in foreach P in C replace with T from P from newC. Is there an other more optimal way to do it?

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• Java interface and abstract class issue

  - by George2

  Hello everyone, I am reading the book -- Hadoop: The Definitive Guide, http://www.amazon.com/Hadoop-Definitive-Guide-Tom-White/dp/0596521979/ref=sr_1_1?ie=UTF8&s=books&qid=1273932107&sr=8-1 In chapter 2 (Page 25), it is mentioned "The new API favors abstract class over interfaces, since these are easier to evolve. For example, you can add a method (with a default implementation) to an abstract class without breaking old implementations of the class". What does it mean (especially what means "breaking old implementations of the class")? Appreciate if anyone could show me a sample why from this perspective abstract class is better than interface? thanks in advance, George

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• How can I make a family of singletons?

  - by Jay

  I want to create a set of classes that share a lot of common behavior. Of course in OOP when you think that you automatically think "abstract class with subclasses". But among the things I want these classes to do is to each have a static list of instances of the class. The list should function as sort of a singleton within the class. I mean each of the sub-classes has a singleton, not that they share one. "Singleton" to that subclass, not a true singleton. But if it's a static, how can I inherit it? Of course code like this won't work: public abstract A { static List<A> myList; public static List getList() { if (myList==null) myList=new ArrayList<A>(10); return myList; } public static A getSomethingFromList() { List listInstance=getList(); ... do stuff with list ... } public int getSomethingFromA() { ... regular code acting against current instance ... } } public class A1 extends A { ... } public class A2 extends A { ... } A1 somethingfromA1List=(A1) A1.getSomethingFromList(); A2 somethingfromA2List=(A2) A2.getSomethingFromList(); The contents of the list for each subclass would be different, but all the code to work on the lists would be the same. The problem with the above code is that I'd only have one list for all the subclasses, and I want one for each. Yes, I could replicate the code to declare the static list in each of the subclasses, but then I'd also have to replicate all the code that adds to the lists and searches the list, etc, which rather defeats the purpose of subclassing. Any ideas on how to do this without replicating code?

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• Are these jobs for developer or designers or for client itself? for a web-site projects

  - by jitendra

  Spell checking grammar checking Descriptive alt text for big chart , graph images, technical images To write Table summary and caption Descriptive Link text Color Contrast checking Deciding in content what should be H2 ,H3, H4... and what should be <strong> or <span class="boldtext"> Meta Description and keywords for each pages Image compression To decide Filenames for images,PDf etc To decide Page's <title> for each page

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• "FirstName" and "LastName" store in database USER or USER_PROFILE table?

  - by Khou

  Currently I store the user's "FirstName" and "LastName" in the USER table, but i also have a USER PROFILE table (which provides additional information about the user) and it would makes sense to have the user's "FirstName" and "LastName" in the USER PROFILE table aswell. So what do i do? make two copies of "FirstName" and "LastName"?

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• Creating an object relational schema from a Class diagram

  - by Caylem

  Hi Ladies and Gents. I'd like some help converting the following UML diagram: UML Diagram The diagram shows 4 classes and is related to a Loyalty card scheme for an imaginary supermarket. I'd like to create an object relational data base schema from it for use with Oracle 10g/11g. Not sure where to begin, if somebody could give me a head start that would be great. Looking for actually starting the schema, show abstraction, constraints, types(subtypes, supertypes) methods and functions. Note: I'm not looking for anyone to make any comments regarding the actual classes and whether changes should be made to the Diagram, just the schema. Thanks

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• Should I use custom exceptions to control the flow of application?

  - by bonefisher

  Is it a good practise to use custom business exceptions (e.g. BusinessRuleViolationException) to control the flow of user-errors/user-incorrect-inputs??? The classic approach: I have a web service, where I have 2 methods, one is the 'checker' (UsernameAlreadyExists()) and the other one is 'creator' (CreateUsername())... So if I want to create a username, I have to do 2 roundtrips to webservice, 1.check, 2.if check is OK, create. What about using UsernameAlreadyExistsException? So I call only the 2. web service method (CrateUsername()), which contains the check and if not successfull, it throws the UsernameAlreadyExistsException. So the end goal is to have only one round trip to web service and the checking can be contained also in other web service methods (so I avoid calling the UsernameAlreadyExists() all the times..). Furthermore I can use this kind of business error handling with other web service calls completely avoiding the checking prior the call.

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• Perls Of Wisdom For a .Net Programmer [closed]

  - by DeanMc

  Hi Guys, I like to think that recently I have moved from complete beginner to beginner. It has been a hard road and one on which I took many wrong turns. Very rarely in any profession is there a place where so many rock stars gather, this is something I would like to take advantage of. What I would like to ask is what are your perls of wisdom for a .net programmer. They can be anything you feel of value, a concept, a book, a process that should be followed, anything of that nature, it doesn't have to be .net specific just contextual. Thanks for taking the time to read this and respond.

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• How should I use color in my application? Single, Theme, or Chaos?

  - by CodeSlave

  How should I be using color in my application? I have over a 100 different forms (windows) in my application, and the default windows grey seems like a bad choice to me. One school of thought says pick one neutral color, and use the same one everywhere. Another school of thought says pick a set of neutral colors, and use them same ones within a group of form (e.g., shipping screens might be light green, receiving screens light orange, user administration screens light blue, etc.). The final school of thought says make every form different. We've got millions of colors, why not use them? What should I do and why?

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• Autmatically create table on MySQL server based on date?

  - by Anthony

  Is there an equivalent to cron for MySQL? I have a PHP script that queries a table based on the month and year, like: SELECT * FROM data_2010_1 What I have been doing until now is, every time the script executes it does a query for the table, and if it exists, does the work, if it doesn't it creates the table. I was wondering if I can just set something up on the MySQL server itself that will create the table (based on a default table) at the stroke of midnight on the first of the month. Update Based on the comments I've gotten, I'm thinking this isn't the best way to achieve my goal. So here's two more questions: If I have a table with thousands of rows added monthly, is this potentially a drag on resources? If so, what is the best way to partition this table, since the above is verboten? What are the potential problems with my home-grown method I originally thought up?

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• StockTrader RI > Controllers, Presenters, WTF?

  - by SandRock

  I am currently learning how to make advanced usage of WPF via the Prism (Composite WPF) project. I watch many videos and examples and the demo application StockTraderRI makes me ask this question: What is the exact role of each of the following part? SomethingService: Ok, this is something to manage data SomethingView: Ok, this is what's displayed SomethingPresentationModel: Ok, this contains data and commands for the view to bind to (equivalent to a ViewModel). SomethingPresenter: I don't really understand it's usage SomethingController: Don't understand too I saw that a Presenter and a Controller are not necessary but I would like to understand why they are here. Can someone tell me their role and when to use them?

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• Placement of defensive structures in a game

  - by Martin

  I am working on an AI bot for the game Defcon. The game has cities, with varying populations, and defensive structures with limited range. I'm trying to work out a good algorithm for placing defence towers. Cities with higher populations are more important to defend Losing a defence tower is a blow, so towers should be placed reasonably close together Towers and cities can only be placed on land So, with these three rules, we see that the best kind of placement is towers being placed in a ring around the largest population areas (although I don't want an algorithm just to blindly place a ring around the highest area of population, sometime there might be 2 sets of cities far apart, in which case the algorithm should make 2 circles, each one half my total towers). I'm wondering what kind of algorithms might be used for determining placement of towers?

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