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  • C# Pass Generics At Runtime

    - by TheCloudlessSky
    I have a method like the following: public IEnumerable<T> GetControls<T>() : where T : ControlBase { // removed. } I then created a class: public class HandleBase<TOwner> : ControlBase : TOwner { // Removed } I'd like to be able to call GetControls<HandleBase<this.GetType()>>; where it would use the type of THIS class to pass to the HandleBase. This would in essentially get all HandleBase that have an owner of THIS type. How can I achieve this?

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  • Travelling Salesman Problem Constraint Representation

    - by alex25
    Hey! I read a couple of articles and sample code about how to solve TSP with Genetic Algorithms and Ant Colony Optimization etc. But everything I found didn't include time (window) constraints, eg. "I have to be at customer x before 12am)" and assumed symmetry. Can somebody point me into the direction of some sample code or articles that explain how I can add constraints to TSP and how I can represent those in code. Thanks!

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  • Getters and Setters: Code smell, Necessary Evil, or Can't Live Without Them [closed]

    - by Avery Payne
    Possible Duplicate: Allen Holub wrote “You should never use get/set functions”, is he correct? Is there a good, no, a very good reason, to go through all the trouble of using getters and setters for object-oriented languages? What's wrong with just using a direct reference to a property or method? Is there some kind of "semantical coverup" that people don't want to talk about in polite company? Was I just too tired and fell asleep when someone walked out and said "Thou Shalt Write Copious Amounts of Code to Obtain Getters and Setters"? Follow-up after a year: It seems to be a common occurrence with Java, less so with Python. I'm beginning to wonder if this is more of a cultural phenomena (related to the limitations of the language) rather than "sage advice". The -1 question score is complete for-the-lulz as far as I am concerned. It's interesting that there are specific questions that are downvoted, not because they are "bad questions", but rather, because they hit someone's raw nerve.

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  • What is the simplest, but solid, interface from WinForms to a SQL Server database?

    - by Greg
    Hi, If I wanted to have my data in SQL Server, but wanted to use a thick client WinForms application for users, what would be the best practice way to have calls occurring from WinForms to database? And how simple is this? I guess I'm trying to gauge to what extent there are issues with this approach and one needs to go for some (a) middle tier with web services, or (b) have to go asp.net or something. I really just have a simple app that needs a database and I'll only have a 10 - 30 clients on a LAN/WAN network that would be connecting in.

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  • Automatically reporting javascript errors to the developer

    - by Cine
    As most production environments we have setup something to send us a notification if there is an error in our web application. The problem is ofcourse that this only covers errors on the server side. My question to the community is: What are you doing about client side errors, especially in javascript? And what about other quality of service issues, such as slow processing and other things that might be due to the client machine?

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  • Database table relationships: Always also relate to specified value (Linq to SQL in .NET Framework)

    - by sinni800
    I really can not describe my question better in the title. If anyone has suggestions: Please tell! I use the Linq to SQL framework in .NET. I ran into something which could be easily solved if the framework supported this, it would be a lot of extra coding otherwise: I have a n to n relation with a helper table in between. Those tables are: Items, places and the connection table which relates items to places and the other way. One item can be found in many places, so can one place have many items. Now of course there will be many items which will be in ALL places. Now there is a problem: Places can always be added. So I need a place-ID which encompasses ALL places, always. Like maybe a place-id "0". If the helper table has a row with the place-id of zero, this should be visible in all places. In SQL this would be a simple "Where [...] or place-id = 0", but how do I do this in Linq relations? Also, for a little side question: How could I manage "all but this place" kind of exclusions?

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  • How to extend a large website to an iPhone app?

    - by xoail
    I am trying to create an iPhone app for a large website (as big as amazon.com) and it involves using cookies and what not to get authenticated via the Apache intercepter and access the web services exposed by the main website. For that I am looking for strategies to go about developing it. I am new to iPhone development and I am mostly looking for some architectural guidance. Does anyone know how services like eBay and Amazon work seamlessly across the website and iPhone app?

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  • friendship database schema

    - by Daniel Hertz
    I'm creating a db schema that involves users that can be friends, and I was wondering what the best way to model the ability for these friends to have friendships. Should it be its own table that simply has two columns that each represent a user? Thanks!

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  • Shipping jar with default .properties file configurations

    - by Maxim Veksler
    Hello, I would like to include a default default.properties file in my .jar library. The idea is to allow the user to override my default is he so desires. I'm having trouble getting the classloader to play nicely with this setup, I've tried to look a at popular jars such as log4j, common-* and others and it seems that no one is implementing this idea. Am I going the wrong way? The second best thing is hard coding the values, and using the default if no .properties key has been found, but this sound oh so wrong. Suggestions?

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  • Why use hashing to create pathnames for large collections of files?

    - by Stephen
    Hi, I noticed a number of cases where an application or database stored collections of files/blobs using a has to determine the path and filename. I believe the intended outcome is a situation where the path never gets too deep, or the folders ever get too full - too many files (or folders) in a folder making for slower access. EDIT: Examples are often Digital libraries or repositories, though the simplest example I can think of (that can be installed in about 30s) is the Zotero document/citation database. Why do this? EDIT: thanks Mat for the answer - does this technique of using a hash to create a file path have a name? Is it a pattern? I'd like to read more, but have failed to find anything in the ACM Digital Library

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  • How to restrict an access to some of the functions at third level in Classes (OOPs)

    - by Shantanu Gupta
    I have created a class say A which has some functions defined as protected. Now Class B inherits A and class C inherits B. Class A has private default constructor and protected parameterized constructor. I want Class B to be able to access all the protected functions defined in Class A but class C can have access on some of the functions only not all the functions and class C is inheriting class B. How can I restrict access to some of the functions of Class A from Class C ? Class A { private A(){} protected A(int ){} } Class B : A {} CLass C:B { }

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  • Where are the new ideas in programming languages?

    - by 0xF
    I've recently been looking into the topic of programming languages and from what I've seen, few to none serious languages try making really "new" things that were not seen before their creation. Why do all more or less successful programming languages since 1980 or so just combine aspects of their predecessors? I just can't believe that programming languages "can't get any better"..

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  • Designing software interface for various screen sizes

    - by Tower
    Hi, Nowadays we have screens like 1920x1200 and 1680x1050 in popular use and some even use 2560x1600 resolution while some older systems still rely on a 800x600 resolution. I am writing a software that looks good on a 1680x1050, but too small on a 1920x1200 and too large on a 1024x768. Do you have suggestions how to go for designing an application for various screen sizes? Things were a lot simpler before when we had little differences in resolutions, but now it seems there's no good way of handling this. I know this question is more about designing / layout than programming, but I bet this is more or less part of programmers life so I made this post here.

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  • Designing a frontend/backend architecture

    - by wrp
    What are some good information sources on designing programs with a client/server architecture? This is for development of a desktop application, not a Web service. The only books I have found on client/server apps deal with the case of a thin client connecting to a remote database. Two good examples of what I mean are Mathematica and SuperCollider. I'm looking for platform- and language-agnostic discussion of the issues in developing a frontend/backend system. Especially useful topics would be allocation of responsibilities and options for message passing.

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  • In a star schema, are foreign key constraints between facts and dimensions neccessary?

    - by Garett
    I'm getting my first exposure to data warehousing, and I’m wondering is it necessary to have foreign key constraints between facts and dimensions. Are there any major downsides for not having them? I’m currently working with a relational star schema. In traditional applications I’m used to having them, but I started to wonder if they were needed in this case. I’m currently working in a SQL Server 2005 environment.

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  • In what package should a "Settings" class be?

    - by Tom
    I've in the middle of building an application but found myself too easily creating new packages without keeping the project's structure in mind. Now, I'm trying to redo the whole project structure on paper first. I am using a Settings class with public properties, accessed as settings for several other classes around the project. Now, since this Settings class applies for the whole project, I am unsure if it should be packaged and if so, in what kind of package should it exist? Or should it be in the root (the default package) with the main application class? I've been thinking about putting it in my utils package, then again I don't think it really is an utlity. Any strategies on how to decide on such package structure for example for a Settings class?

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  • c# multi threaded file processing

    - by user177883
    There is a folder that contains 1000 of small text files. I aim to parse and process all of them while more files are being populated in to the folder. My intention is to multithread this operation as the single threaded prototype took 6 minutes to process 1000 files. I like to have reader and writer thread(s) as following : while the reader thread(s) are reading the files, I d like to have writer thread(s) to process them. Once the reader is started reading a file, I d like to mark it as being processed, such as by renaming it, once it s read, rename it to completed. How to approach such multithreaded application ? Is it better to use a distributed hash table or a queue? Which data structure to use that would avoid locks? Would you have a better approach to this scheme that you like to share?

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  • How to disable UI control based on domain object's state?

    - by Subb
    Here's my problem. I have a somewhat complex domain object, which, depending on its state, responds to certain actions. I think the state pattern is pretty much the solution for that. However, I need to display which actions are possible at any moment in the UI. Ex: The domain object is an audio player. Some songs can't be skipped (like ads), so I need to disable the "next" and "previous" buttons in the GUI so the user have some kind of feedback of which action he can execute. I've looked at Swing's Action class (note: this is not a Java project), but I think I would need to keep every Actions in my domain object class (audio player), so it can enable or disable them depending on its own state (thus, affecting the UI). Is it the way to do it?

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  • Search for a pattern in a list of strings - Python

    - by Holtz
    I have a list of strings containing filenames such as, file_names = ['filei.txt','filej.txt','filek.txt','file2i.txt','file2j.txt','file2k.txt','file3i.txt','file3j.txt','file3k.txt'] I then remove the .txt extension using: extension = os.path.commonprefix([n[::-1] for n in file_names])[::-1] file_names_strip = [n[:-len(extension)] for n in file_names] And then return the last character of each string in the list file_names_strip: h = [n[-1:] for n in file_names_strip] Which gives h = ['i', 'j', 'k', 'i', 'j', 'k', 'i', 'j', 'k'] How can i test for a pattern of strings in h? So if i,j,k occur sequentially it would return True and False if not. I need to know this because not all file names are formatted like they are in file_names. So: test_ijk_pattern(h) = True no_pattern = ['1','2','3','1','2','3','1','2','3'] test_ijk_pattern(no_pattern) = False

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  • Auto increment with a Unit Of Work

    - by Derick
    Context I'm building a persistence layer to abstract different types of databases that I'll be needing. On the relational part I have mySQL, Oracle and PostgreSQL. Let's take the following simplified MySQL tables: CREATE TABLE Contact ( ID varchar(15), NAME varchar(30) ); CREATE TABLE Address ( ID varchar(15), CONTACT_ID varchar(15), NAME varchar(50) ); I use code to generate system specific alpha numeric unique ID's fitting 15 chars in this case. Thus, if I insert a Contact record with it's Addresses I have my generated Contact.ID and Address.CONTACT_IDs before committing. I've created a Unit of Work (amongst others) as per Martin Fowler's patterns to add transaction support. I'm using a key based Identity Map in the UoW to track the changed records in memory. It works like a charm for the scenario above, all pretty standard stuff so far. The question scenario comes in when I have a database that is not under my control and the ID fields are auto-increment (or in Oracle sequences). In this case I do not have the db generated Contact.ID beforehand, so when I create my Address I do not have a value for Address.CONTACT_ID. The transaction has not been started on the DB session since all is kept in the Identity Map in memory. Question: What is a good approach to address this? (Avoiding unnecessary db round trips) Some ideas: Retrieve the last ID: I can do a call to the database to retrieve the last Id like: SELECT Auto_increment FROM information_schema.tables WHERE table_name='Contact'; But this is MySQL specific and probably something similar can be done for the other databases. If do this then would need to do the 1st insert, get the ID and then update the children (Address.CONTACT_IDs) – all in the current transaction context.

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  • internal implementation of database Queries

    - by harigm
    In my experience I have used many queries like select, order by, where clause etc.. in mysql, sql-server, oracle etc For a moment i have thought, 1)how is this internally written to implement the above queries 2) which language do they use? 3) is that programming language? if yes which language? 4)what kind of environment required to implement this kind of complex database

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  • Patterns for wrapping a command line tool in another language

    - by Tom Duckering
    I'm currently writing some Java to wrap around an extensive command line tool. It feels like I'm writing a lot of similar code. I'm wondering if there are any established patterns for wrapping command line tools - passing arguments and handling output and so on. Specific examples in Java would obviously be great, but any general suggestions or pointers are welcome too.

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  • Feature categories for a social network

    - by mafutrct
    Not sure if this question belongs on SO. Anyway, please let me try to clarify the issue. I'm currently planning a social program. It's basically a chat server with the major additional ability to play games. I'd like to create categories of features that are offered to users. My question is, are there any useful standard feature categories? Does not have to be specific to my case, I'm interested in the general case as well. Just to give you an idea of what I'm thinking: functional e.g. play games social e.g. chatting operational e.g. 24/7 service availability I'm entirely unsure if this is the right place to ask, if you know of any better site to ask please don't hesitate to add a comment.

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