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• Best canvas for drawing in wxPython?

  - by Pablo Rodriguez

  I have to draw a graph of elements composing a topological model of a physical network. There would be nodes and arches, and the latter could be unidirectional or bidirectional. I would like to capture the clicking events for the nodes and the arches (to select the element and show its properties somewhere), and the dragging events for the nodes (to move them around) and arches (to connect or disconnect elements). I've done some research and I've narrowed the alternatives down to OGL (Object Graphics Library) and FloatCanvas. I would not like to go down to the DrawingContext, but it is not discarded if necessary. Which canvas option would you choose?

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• Hibernate Unit tests - Reset schema

  - by Marco

  Hi, I'm testing the CRUD operations of my DAOs in JUnit tests. When i execute the single test, Hibernate always resets the schema and populates the DB in a known state. But when i execute multiple tests in a row, Hibernate resets the schema once, and then the data is accumulated during the execution of the tests. This is an unexpected behavior, so I'd like to add in the @Before method of the tests a function that explicitly resets the schema to avoid the pesistence of side data created by previous tests during the execution chain. Any tips? Thanks

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• Known problems with filemtime() on Windows - files getting touched arbitrarily?

  - by Pekka

  Is there a known issue leading to file modification times of cache files on Windows XP SP 3 getting arbitrarily updated, but without any actual change? Is there some service on a standard Windows XP - Backup, Sync, Versioning, Virus scanner - known to touch files? They all have a .txt extension. If there isn't, forget it. Then I'm getting something wrong in my cache routines, and I'll debug my way through. Background: I'm building a simple caching wrapper around a slow web site on a Windows server. I am comparing the filemtime() time stamp to some columns in the data base to determine whether a cached file is stale. I'm having problems using this method because the modification time of the cache files seems to get updated in between operations without me doing anything. THis results in stale files being displayed. I'm the only user on the machine. The operating system is Windows XP, the webserver a XAMPP Apache 2 with PHP 5.2

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• Controlling read and write access width to memory mapped registers in C

  - by srking

  I'm using and x86 based core to manipulate a 32-bit memory mapped register. My hardware behaves correctly only if the CPU generates 32-bit wide reads and writes to this register. The register is aligned on a 32-bit address and is not addressable at byte granularity. What can I do to guarantee that my C (or C99) compiler will only generate full 32-bit wide reads and writes in all cases? For example, if I do a read-modify-write operation like this: volatile uint32_t* p_reg = 0xCAFE0000; *p_reg |= 0x01; I don't want the compiler to get smart about the fact that only the bottom byte changes and generate 8-bit wide read/writes. Since the machine code is often more dense for 8-bit operations on x86, I'm afraid of unwanted optimizations. Disabling optimizations in general is not an option.

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• hadoop - large database query

  - by Mastergeek

  Situation: I have a Postgres DB that contains a table with several million rows and I'm trying to query all of those rows for a MapReduce job. From the research I've done on DBInputFormat, Hadoop might try and use the same query again for a new mapper and since these queries take a considerable amount of time I'd like to prevent this in one of two ways that I've thought up: 1) Limit the job to only run 1 mapper that queries the whole table and call it good. or 2) Somehow incorporate an offset in the query so that if Hadoop does try to use a new mapper it won't grab the same stuff. I feel like option (1) seems more promising, but I don't know if such a configuration is possible. Option(2) sounds nice in theory but I have no idea how I would keep track of the mappers being made and if it is at all possible to detect that and reconfigure. Help is appreciated and I'm namely looking for a way to pull all of the DB table data and not have several of the same query running because that would be a waste of time.

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• In game programming are global variables bad?

  - by Joe.F

  I know my gut reaction to global variables is "badd!" but in the two game development courses I've taken at my college globals were used extensively, and now in the DirectX 9 game programming tutorial I am using (www.directxtutorial.com) I'm being told globals are okay in game programming ...? The site also recommends using only structs if you can when doing game programming to help keep things simple. I'm really confused on this issue, and all the research I've been trying to do is very confusing. I realize there are issues when using global variables (threading issues, they make code harder to maintain, the state of them is hard to track etc) but also there is a cost associated with not using globals, I'd have to pass a loooot of information around very often which can be confusing and I imagine time-costing, although I guess pointers would speed the process up (this is my first time writing a game in C++.) Anyway, I realize there is probably no "right" or "wrong" answer here since both ways work, but I want my code to be as proper as I can so any input would be good, thank you very much!

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• How do I count the number of bytes read by TextReader.ReadLine()?

  - by Steve Guidi

  I am parsing a very large file of records (one per line, each of varying length), and I'd like to keep track of the number of bytes I've read in the file so that I may recover in the event of a failure. I wrote the following: string record = myTextReader.ReadLine(); bytesRead += record.Length; ParseRecord(record); However this doesn't work since ReadLine() strips any CR/LF characters in the line. Furthermore, a line may be terminated by either CR, LF, or CRLF characters, which means I can't just add 1 to bytesRead. Is there an easy way to get the actual line length, or do I write my own ReadLine() method in terms of the granular Read() operations?

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• How to handle images folder with many images

  - by Billy

  I'm developing a new aspnet website with 200k images in a /Images/ -folder. Many operations in Visual Studio is slow because it access the folder, adding a web service takes 10 minutes. The images is not checked into scm (svn). How should I structure the tree of code, to improve performance in VS? It would also be neat if not all developers needed to copy 200k images to their local disk to be able to develop on the site. Images as DB blobs is not an option.

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• How to host your own http-like server using ServiceHost?

  - by Ole Jak

  I use ServiceHost for hosting WCF cervices. I want to host near to my WCF services my own tcp programm (like WCF service but with out WCF) for direct sockets operations (like lien to some sort of broadcasting TCP stream) I want to use ServiceHost for somehow simplyfiing proces of creating my TCP sender\listener, to somehow control namespaces (so I would be able to let my clients to send TCP streams directly into my service using some nice URLs like www.example.com:34123/myserver/stream?id=1 or www.example.com:34123/myserver/stream?id=222 and so that I will not be bothered with Idea of 1 client for 1 socket at one time moment, BTW I realy want to keep my WCF services on the same port as my own server or what it is...) Can any body please hrlp me with this?

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• Send and receive data trough the power network

  - by luvieere

  I'm not interested in a hardware solution, I want to know about software that may "read" modulated signal received trough the power supply - some sort of a low-level driver that would access the power signal in a convenient place and demodulate it. Is there a way to receive signal from the computer's power supply? I'm interested in an API or library that would allow the computer to be seen as a node in a Power Line Communication network and receive data directly through the power cable, without the need for a converter. Is there any active research in this field? Edit: There is software that reads monitors and displays internal component voltages - DC voltage after being converted and filtered by the power supply - now I need is a method of data encoding that would be invariant to conversion and filtering, the original signal embedded in AC being present in some form within the converted DC signal.

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• Is there a Windows utility that will let me do multiple programmatic find/replaces on text that I cu

  - by billmaya

  I've inherited some C# code that contains about a thousand lines of source that I need to modify, transforming it from this: newDataRow["to_dir"] = comboBox108.Text; To this: assetAttributes.Add("to_dir", comboBox108.Text); The lines occur in various places throughout the application in groups of 40 or 50. Modifying each line by hand in Visual Studio 2008 can be done but it's labor intensive and prone to errors. Is there a Windows utility out there that will let me cut and paste groups of code into it and then run some sort of reg-ex expression to transform the individual lines one-by-one? I'd also be willing to use some sort of VS 2008 add-in that performed the same set of reg-ex operations against a selection of code. Thanks in advance.

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• Transaction within transaction

  - by user281521

  Hello, I want to know if open a transaction inside another is safe and encouraged? I have a method: def foo(): session.begin try: stuffs except Exception, e: session.rollback() raise e session.commit() and a method that calls the first one, inside a transaction: def bar(): stuffs try: foo() #<<<< there it is :) stuffs except Exception, e: session.rollback() raise e session.commit() if I get and exception on the foo method, all the operations will be rolled back? and everything else will work just fine? thanks!!

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• Relationships via Email Rather Than User List

  - by Bob Lerner

  I'm new at Drupal, so I may have missed a solution despite a lot of research: I want users to be able to invite non-users and other users into a named relationship they've set up (using e.g. the Friendlist or User Relationships module) using only email addresses and not the user list. I believe that invitations from both of those modules are done only after the inviter selects the invitee after selecting the invitee from a list of all users. Frankly, I would be surprised if no email solution exists since a large site's user list would be daunting. Does anyone know if this is possible using Organic Groups? Thanks very much.

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• SQL Server 2005 - Understanding ouput of DBCC SHOWCONTIG

  - by user169743

  I'm seeing some slow performance on a SQL Server 2005 database. I've been doing some research regarding SQL Server performance but I'm having difficulty fully understanding the output of SHOWCONTIG and would be very grateful if someone could have a look and offer some suggestions to improve performance. TABLE level scan performed. Pages Scanned................................: 19348 Extents Scanned..............................: 2427 Extent Switches..............................: 3829 Avg. Pages per Extent........................: 8.0 Scan Density [Best Count:Actual Count].......: 63.16% [2419:3830] Logical Scan Fragmentation ..................: 8.40% Extent Scan Fragmentation ...................: 35.15% Avg. Bytes Free per Page.....................: 938.1 Avg. Page Density (full).....................: 88.41%

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• I want to use Google Map API for my Desktop application

  - by Nubkadiya

  i want to use google map api for my desktop application. the application will be totally connected to internet. while i was searching some research notes about this implementation. i found a ideal site with the configurations. but it has some java files to be downloaded. but when i tried that website its not loading. which is swinglabs.org http://today.java.net/pub/a/today/2007/10/30/building-maps-into-swing-app-with-jxmapviewer.html any other options of doing this api implementation to my desktop application. and one more thing. i tried downloading the google api. even it ask a url. we have to provide a url then only we get a key to download it. and the api should run in that specific url. otherwise its not working. how this appears to a desktop application any ideas welcome..

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• Is It Worth Using Bitwise Operators In Methods?

  - by user1626141

  I am very new to Java (and programming in general, my previous experience is with ActionScript 2.0 and some simple JavaScript), and I am working my way slowly and methodically through Java: A Beginner's Guide by Herbert Schildt. It is an incredible book. For one thing, I finally understand more-or-less what bitwise operators (which I first encountered in ActionScript 2.0) do, and that they are more efficient than other methods for certain sums. My question is, is it more efficient to use a method that uses, say, a shift right, to perform all your divisions/2 (or divisions/even) for you in a large program with many calculations (in this case, a sprawling RPG), or is it more efficient to simply use standard mathematical operations because the compiler will optimise it all for you? Or, am I asking the wrong question entirely?

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• Running applictions via ruby and multi-core support? (OSX)

  - by Nick Faraday

  Hi All, I'm looking for some tutorials/resources/tips that will show me how to run applications via a ruby script. I have several small tools that we use in our day to day operations that I want to manage their tasks in one ruby script. Basically what I'm trying to do is: run app via ruby script. (wait for result) get result code (success, or error msg) if ok, start the app on its next task. Also each of the tasks are independent so I'd like to take advantage of the 8 cores on my MacPro and run 8 instances at a time. Any resources you could point me towards would be greatly appreciated!

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• Which relational databases exist with a public API for a high level language?

  - by Jens Schauder

  We typically interface with a RDBMS through SQL. I.e. we create a sql string and send it to the server through JDBC or ODBC or something similar. Are there any RDBMS that allow direct interfacing with the database engine through some API in Java, C#, C or similar? I would expect an API that allows constructs like this (in some arbitrary pseudo code): Iterator iter = engine.getIndex("myIndex").getReferencesForValue("23"); for (Reference ref: iter){ Row row = engine.getTable("mytable").getRow(ref); } I guess something like this is hidden somewhere in (and available from) open source databases, but I am looking for something that is officially supported as a public API, so one finds at least a note in the release notes, when it changes. In order to make this a question that actually has a 'best' answer: I prefer languages in the order given above and I will prefer mature APIs over prototypes and research work, although these are welcome as well.

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• Identify a non-computer network device?

  - by Avilan

  I'm current working on a program that scans my network and discoveres computers and devices on the network. I use various operations to find data on the devices I discover, but want to distinguish the network devices from computers. And I'm wondering if anyone knows how I could do this? I looked a bit at SNMP, and tried connecting to my network printer, router and modem. But I seem to only be able to connect to the printer, neither the router or modem responds. Is there another way to identify what kind of a device an IP address belongs to?

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• Is this bad style of programming(C#) ?

  - by m0s

  Hi, so in my program I have parts where I use try catch blocks like this try { DirectoryInfo dirInfo = new DirectoryInfo(someString); //I don't know if that directory exists //I don't know if that string is valid path string... it could be anything //Some operations here } catch(Exception iDontCareWhyItFailed) { //Didn't work? great... we will say: somethings wrong, try again/next one } Of course I probably could do checks to see if the string is valid path (regex), then I would check if directory exists, then I could catch various exceptions to see why my routine failed and give more info... But in my program it's not really necessary. Now I just really need to know if this is acceptable, and what would a pro say/think about that. Thanks a lot for attention.

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• What's exactly the nature of .Net Framework 3.5 Service Pack1?

  - by Richard77

  Hello, I did some recovery disk operations with my laptop because it became instable. Now, I'm about to re-install SQL Server 2008 Professional, but it keeps telling me that I need to install .net framework 3.5 with service pack1. What's strange is I was asked to do the same when I installed Visual Studio 2008 Professional earlier. I'd like to know: what's .Net Framework Service Pack1? is it One piece of software sitting on top of windows ? Several software having the same name so that Visual Studio has it, SQL Server also has it, and do on... And why the naming Service Pack1 behind .Net Framework? I'm really lost. Thanks for helping

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• Backbone.js "model" query

  - by Novice coder

  I'm a learning coder trying to understand this code from a sample MVC framework. The below code is from a "model" file. I've done research on Backbone.js, but I'm still confused as to exactly how this code pull information from the app's database. For example, how are base_url, Model.prototype, and Collection.prototype being used to retrieve information from the backend? Any help would be greatly appreciated. exports.definition = { config : { "defaults": { "title": "-", "description": "-" }, "adapter": { "type": "rest", "collection_name": "schools", "base_url" : "/schools/", } }, extendModel: function(Model) { _.extend(Model.prototype, { // Extend, override or implement Backbone.Model urlRoot: '/school/', name:'school', parse: function(response, options) { response.id = response._id; return response; }, }); return Model; }, extendCollection: function(Collection) { _.extend(Collection.prototype, { // Extend, override or implement Backbone.Collection urlRoot: '/schools/', name: 'schools', }); return Collection; } }

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• Balanced Search Tree Query, Asymtotic Analysis..

  - by AGeek

  Hi, The situation is as follows:- We have n number and we have print them in sorted order. We have access to balanced dictionary data structure, which supports the operations serach, insert, delete, minimum, maximum each in O(log n) time. We want to retrieve the numbers in sorted order in O(n log n) time using only the insert and in-order traversal. The answer to this is:- Sort() initialize(t) while(not EOF) read(x) insert(x,t); Traverse(t); Now the query is if we read the elements in time "n" and then traverse the elements in "log n"(in-order traversal) time,, then the total time for this algorithm (n+logn)time, according to me.. Please explain the follow up of this algorithm for the time calculation.. How it will sort the list in O(nlogn) time?? Thanks.

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• Using Selenium 2's IWebDriver to interact with elements on the page

  - by Andreas Grech

  I'm using Selenium's IWebDriver to write Unit Tests in C#. Such is an example: IWebDriver defaultDriver = new InternetExplorerDriver(); var ddl = driver.FindElements(By.TagName("select")); The last line retrieves the select HTML element wrapped in a IWebElement. I need a way to simulate selection to a specific option in that select list but I can't figure out how to do it. Upon some research, I found examples where people are using the ISelenium DefaultSelenium class to accomplish the following, but I am not making use of this class because I'm doing everything with IWebDriver and INavigation (from defaultDriver.Navigate()). I also noticed that ISelenium DefaultSelenium contains a ton of other methods that aren't available in the concrete implementations of IWebDriver. So is there any way I can use IWebDriver and INavigation in conjunction with ISelenium DefaultSelenium ?

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• Compiler reordering around mutex boundaries?

  - by shojtsy

  Suppose I have my own non-inline functions LockMutex and UnlockMutex, which are using some proper mutex - such as boost - inside. How will the compiler know not to reorder other operations with regard to calls to the LockMutex and UnlockMutex? It can not possibly know how will I implement these functions in some other compilation unit. void SomeClass::store(int i) { LockMutex(_m); _field = i; // could the compiler move this around? UnlockMutex(_m); } ps: One is supposed to use instances of classes for holding locks to guarantee unlocking. I have left this out to simplify the example.

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