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  • Strange Matlab error: "??? Subscript indices must either be real positive integers or logicals"

    - by Roee Adler
    I have a function func that returns a vector a. I usually plot a and then perform further analysis on it. I have a certain scenario when once I try to plot a, I get a "??? Subscript indices must either be real positive integers or logicals" error. Take a look at the following piece of code to see the vector's behavior: K>> a a = 5.7047 6.3529 6.4826 5.5750 4.1488 5.8343 5.3157 5.4454 K>> plot(a) ??? Subscript indices must either be real positive integers or logicals. K>> for i=1:length(a); b(i) = a(i); end; K>> b b = 5.7047 6.3529 6.4826 5.5750 4.1488 5.8343 5.3157 5.4454 K>> plot(b) ??? Subscript indices must either be real positive integers or logicals. The scenario where this happens is when I call function func from within another function (call it outer_func), and return the result directly as outer_func's result. When debugging inside outer_func, I can plot a properly, but outside the scope of outer_func, its result has the above behavior. What can cause this? Where do I start from?

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  • Designing DAOs around a JSON API for iPhone Development

    - by Bob Spryn
    So I've been trying to design a clean way of grabbing data for my models in iPhone land. All the data for my application is coming from JSON API's. So right now when a VC needs some models, it does the JSON call itself (asynch) and when it receives the data, it builds the models. It works, but I'm trying to think of a cleaner method whereby the DAO's retrieve the information for me and return the models, all in an async manner. My initial thought is build a protocol for my DAOs, such that the VC would instantiate a DAO and make itself the delegate. When you requested data [DAOinstance getAllUsers] the DAO would do all the network request stuff, and then when it had the data, it would call a method on its delegate (the VC) to pass the data. So I think that's a cool solution, but realized that if I needed to use the same DAO for different purposes in the same VC, my delegate method would have to branch logic depending on which DAO instance initiated the request. So my second thought was to be able to pass 'handler' selectors to the DAO object a la typical javascript patterns. So instead of an official protocol, I would say something like [DAOinstance getAllUsersWithSelector:"TheHandlerFunctionOnMyVC:"] Then when the DAO completed its network activities, it would call the passed selector on the VC, and pass the data back. So am I headed in the wrong direction entirely here? Seems like maybe an ok way to go. Any pointers or articles on designing this kind of data layer would be sweet. Thanks! Bob

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  • Django sitemap intermittent www

    - by Jen Z
    The automatic sitemap for my Django site fluctuates between including the www on urls and leaving it out (I'm aiming to have it in all the time). This has ramifications in google not indexing my pages properly so I'm trying to narrow down what would be causing this issue. I have set PREPEND_WWW = True and my site record in the sites framework is set to include the www e.g. it's set to www.example.com as opposed to example.com. I'm using memcached but pages should expire from the cache after 48 hours so I wouldn't have thought that would be causing the issue? You can see the problem in effect at http://www.livingspaceltd.co.uk/sitemap.xml (refresh the page a few times). My sitemaps setup is fairly prosaic so I'm doubtful that that is the issue, but in case it's something obvious I'm missing here's the code: ***urls.py*** sitemaps = { 'subpages': Subpages_Sitemap, 'standalone_pages': Standalone_Sitemap, 'categories': Categories_Sitemap, } urlpatterns = patterns('', (r'^sitemap\.xml$', 'django.contrib.sitemaps.views.sitemap', {'sitemaps': sitemaps}), ... ***sitemaps.py*** # -*- coding: utf-8 -*- from django_ls.livingspace.models import Page, Category, Standalone_Page, Subpage from django.contrib.sitemaps import Sitemap class Subpages_Sitemap(Sitemap): changefreq = "monthly" priority = 0.4 def items(self): return Subpage.objects.filter(restricted_to__isnull=True) class Standalone_Sitemap(Sitemap): changefreq = "weekly" priority = 1 def items(self): return Standalone_Page.objects.all() class Categories_Sitemap(Sitemap): changefreq = "weekly" priority = 0.7 def items(self): return Category.objects.all()

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  • Advanced All In One .NET Framework

    - by alfredo dobrekk
    Hi, i m starting a new project that would basically take input from user and save them to database among about 30 screens, and i would like to find a framework that will allow the maximum number of these features out of the box : .net c#. windows form. unit testing continuous integration screens with lists, combo boxes, text boxes, add, delete, save, cancel that are easy to update when you add a property to your classes or a field to your database. auto completion on controls to help user find its way use of an orm like nhibernate easy multithreading and display of wait screens for user easy undo redo tabbed child windows search forms ability to grant access to some functionnalities according to user profiles mvp/mvvm or whatever design patterns either some code generation from database to c# classe or generation of database schema from c# classes some kind of database versioning / upgrade to easily update database when i release patches to application once in production automatic control resizing code metrics analysis some code generator i can use against my entities that would generate some rough form i can rearrange after code documentation generator ... Any ideas ? I know its lot but i really would like to use existing code to build upon so i can focus on business rules. Could splitting the requirements on 3 or 4 existing open source framework be possible ? Do u have any suggestion to add to the list before starting ? What open source tools would u use to achieve these ?

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  • MySQL DDL error creating tables

    - by Alexandstein
    I am attempting to create tables for a MySQL database, but I am having some syntactical issues. It would seem that syntax checking is behaving differently between tables for some reason. While I've gotten all the other tables to go through, the table, 'stock' doesn't seem to be working, despite seeming to use the same syntax patterns. CREATE TABLE users ( user_id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, username VARCHAR(30) NOT NULL, password CHAR(41) NOT NULL, date_joined DATETIME NOT NULL, funds DOUBLE UNSIGNED NOT NULL, PRIMARY KEY(user_id), UNIQUE KEY(username) ); CREATE TABLE owned_stocks ( id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, user_id SMALLINT UNSIGNED NOT NULL, paid_price DOUBLE UNSIGNED NOT NULL, quantity MEDIUMINT UNSIGNED NOT NULL, purchase_date DATETIME NOT NULL, PRIMARY KEY(id) ); CREATE TABLE tracking_stocks ( ticker VARCHAR(5) NOT NULL, user_id SMALLINT UNSIGNED NOT NULL, PRIMARY KEY(ticker) ); CREATE TABLE stocks ( ticker VARCHAR(5) NOT NULL, last DOUBLE UNSIGNED NOT NULL, high DOUBLE UNSIGNED NOT NULL, low DOUBLE UNSIGNED NOT NULL, company_name VARCHAR(30) NOT NULL, last_updated INT UNSIGNED NOT NULL, change DOUBLE NOT NULL, percent_change DOUBLE NOT NULL, PRIMARY KEY(ticker) ); Am I just missing a really obvious syntactical issue? ERROR: #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'change DOUBLE NOT NULL, percent_change DOUBLE NOT NULL, last DOUBLE' at line 4

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  • How to use a Base ViewModel in Asp.net MVC 2

    - by Picflight
    As I familiarize myself with Asp.Net MVC, I am using MVC 2, I have noticed the use of a BaseViewData class in the Kigg project which I am unsure how to implement. I want each of my ViewModels to have certain values available. Using an iterface comes to mind but I am wondering what the best practice is and how does Kigg do it? Kigg public abstract class BaseViewData { public string SiteTitle { get; set; } // ...other properties } public class UserListViewData : BaseViewData { public string Title { get; set; } // .. other stuff } In my WebForms application I use a BasePage that inherits from System.Web.UI.Page. So, in my MVC project, I have this: public abstract class BaseViewModel { public int SiteId { get; set; } } public class UserViewModel : BaseViewModel { // Some arbitrary ViewModel } Referencing the Kigg methodology, how do I make sure that each of my ViewModel that inherits from the BaseViewModel have the SiteId property? What is the best practice, samples or patterns I should be using?

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  • prevent escaping special characters on textnode(JS-HTML)

    - by UnLoCo
    Hello i followed this snippet http://bytes.com/topic/javascript/answers/504399-get-all-text-nodes var xPathResult = document.evaluate( './/text()[normalize-space(.) != ""]', document.body, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null ); for (var i = 0, l = xPathResult.snapshotLength; i < l; i++) { var textNode = xPathResult.snapshotItem(i); textNode.data = textNode.data.replace(/somePattern/g, 'replacement'); } i want to replace certain patterns like for example |12| with a corresponding emoticon ! but when i do textNode.data.replace("|12|",'<.img src="favicon.ico"/>'); for example the text show is ..<.img src="favicon.ico"/>.. as i inspect the html i find that <.img src="favicon.ico"/> became escaped to &lt;img src="favicon.ico"/&gt; is it possible to prevent this and to let the image show ?? Thank You Note: added extra point here &lt;.img src="favicon.ico"/&gt; in purpose

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  • Database Functional Programming in Clojure

    - by Ralph
    "It is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail." - Abraham Maslow I need to write a tool to dump a large hierarchical (SQL) database to XML. The hierarchy consists of a Person table with subsidiary Address, Phone, etc. tables. I have to dump thousands of rows, so I would like to do so incrementally and not keep the whole XML file in memory. I would like to isolate non-pure function code to a small portion of the application. I am thinking that this might be a good opportunity to explore FP and concurrency in Clojure. I can also show the benefits of immutable data and multi-core utilization to my skeptical co-workers. I'm not sure how the overall architecture of the application should be. I am thinking that I can use an impure function to retrieve the database rows and return a lazy sequence that can then be processed by a pure function that returns an XML fragment. For each Person row, I can create a Future and have several processed in parallel (the output order does not matter). As each Person is processed, the task will retrieve the appropriate rows from the Address, Phone, etc. tables and generate the nested XML. I can use a a generic function to process most of the tables, relying on database meta-data to get the column information, with special functions for the few tables that need custom processing. These functions could be listed in a map(table name -> function). Am I going about this in the right way? I can easily fall back to doing it in OO using Java, but that would be no fun. BTW, are there any good books on FP patterns or architecture? I have several good books on Clojure, Scala, and F#, but although each covers the language well, none look at the "big picture" of function programming design.

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  • Does a CS PhD Help for Software Engineering Career?

    - by SiLent SoNG
    I would like to seek advice on whether or not to take a PhD offer from a good university. My only concern is the PhD will take at least 4 year's commitment. During the period I won't have good monetary income. I am also concerned whether the PhD will help my future career development. My career goal is software engineering only. Some of the PhD info: The PhD is CS related. The research area is Information Retrieval, Machine Learning, and Nature Language Processing. More specifically, the research topic is Deep Web search. Some of backgrounds: I worked in Oracle for 3 years in database development after obtained a CS degree from some good university. In last year I received an email telling an interesting project from a professor and thereafter I was lured into his research team. The team consists of 4 PhD students; those students have little or no industry experiences and their coding skills are really really bad. By saying bad I mean they do not know some common patterns and they do not know pitfalls of the programming languages as well as idioms for doing things right. I guess a at least 4 year commitment is worth of serious consideration. I am 27 at this moment. If I take the offer, that implies I will be 31+ upon graduation. Wah... becoming.. what to say, no longer young. Hence, here I am seeking advice on whether it is good or not to take the PhD offer, and whether a CS PhD is good for my future career growth as a software engineer? I do not intent to go for academia.

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  • How can I superimpose modified loess lines on a ggplot2 qplot?

    - by briandk
    Background Right now, I'm creating a multiple-predictor linear model and generating diagnostic plots to assess regression assumptions. (It's for a multiple regression analysis stats class that I'm loving at the moment :-) My textbook (Cohen, Cohen, West, and Aiken 2003) recommends plotting each predictor against the residuals to make sure that: The residuals don't systematically covary with the predictor The residuals are homoscedastic with respect to each predictor in the model On point (2), my textbook has this to say: Some statistical packages allow the analyst to plot lowess fit lines at the mean of the residuals (0-line), 1 standard deviation above the mean, and 1 standard deviation below the mean of the residuals....In the present case {their example}, the two lines {mean + 1sd and mean - 1sd} remain roughly parallel to the lowess {0} line, consistent with the interpretation that the variance of the residuals does not change as a function of X. (p. 131) How can I modify loess lines? I know how to generate a scatterplot with a "0-line,": # First, I'll make a simple linear model and get its diagnostic stats library(ggplot2) data(cars) mod <- fortify(lm(speed ~ dist, data = cars)) attach(mod) str(mod) # Now I want to make sure the residuals are homoscedastic qplot (x = dist, y = .resid, data = mod) + geom_smooth(se = FALSE) # "se = FALSE" Removes the standard error bands But does anyone know how I can use ggplot2 and qplot to generate plots where the 0-line, "mean + 1sd" AND "mean - 1sd" lines would be superimposed? Is that a weird/complex question to be asking?

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  • How do I get started designing and implementing a script interface for my .NET application?

    - by Peter Mortensen
    How do I get started designing and implementing a script interface for my .NET application? There is VSTA (the .NET equivalent of VBA for COM), but as far as I understand I would have to pay a license fee for every installation of my application. It is an open source application so this will not work. There is also e.g. the embedding of interpreters (IronPython?), but I don't understand how this would allow exposing an "object model" (see below) to external (or internal) scripts. What is the scripting interface story in .NET? Is it somehow trivial in .NET to do this? Background: I have once designed and implemented a fairly involved script interface for a Macintosh application for acquisition and analysis of data from a mass spectrometer (Mac OS, System 7) and later a COM interface for a Windows application. Both were designed with an "object model" and classes (that can have properties). These are overloaded words, but in a scripting interface context object model is essentially a containment hiarchy of objects of specific classes. Classes have properties and lists of contained objects. E.g. like in the COM interfaces exposed in Microsoft Office applications, where the application object can be used to add to its list of documents (with the side effect of creating the GUI representation of a document). External scripts can create new objects in a container and navigate through the content of the hiarchy at any given time. In the Macintosh case scripts could be written in e.g. AppleScript or Frontier. On the Macintosh the implementation of a scripting interface was very complicated. Support for it in Metroworks' C++ class library (the name escapes me right now) made it much simpler.

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  • writing into csv file

    - by arin
    I recived alarms in a form of text as the following NE=JKHGDUWJ3 Alarm=Data Center STALZ AC Failure Occurrence=2012/4/3 22:18:19 GMT+02:00 Clearance=Details=Cabinet No.=0, Subrack No.=40, Slot No.=0, Port No.=5, Board Type=EDS, Site No.=49, Site Type=HSJYG500 GSM, Site Name=Google1 . I need to fill it in csv file so later I can perform some analysis I came up with this namespace AlarmSaver { public partial class Form1 : Form { string filesName = "c:\\alarms.csv"; public Form1() { InitializeComponent(); } private void buttonSave_Click(object sender, EventArgs e) { if (!File.Exists(filesName)) { string header = "NE,Alarm,Occurrence,Clearance,Details"; File.AppendAllText(filesName,header+Environment.NewLine); } StringBuilder sb = new StringBuilder(); string line = textBoxAlarm.Text; int index = line.IndexOf(" "); while (index > 0) { string token = line.Substring(0, index).Trim(); line = line.Remove(0, index + 2); string[] values = token.Split('='); if (values.Length ==2) { sb.Append(values[1] + ","); } else { if (values.Length % 2 == 0) { string v = token.Remove(0, values[0].Length + 1).Replace(',', ';'); sb.Append(v + ","); } else { sb.Append("********" + ","); string v = token.Remove(0, values[0].Length + 1 + values[1].Length + 1).Replace(',', ';'); sb.Append(v + ","); } } index = line.IndexOf(" "); } File.AppendAllText(filesName, sb.ToString() + Environment.NewLine); } } } the results are as I want except when I reach the part of Details=Cabinet No.=0, Subrack No.=40, Slot No.=0, Port No.=5, Board Type=KDL, Site No.=49, Site Type=JDKJH99 GSM, Site Name=Google1 . I couldnt split them into seperate fields. as the results showing is as I want to split the details I want each element in details to be in a column to be somthin like its realy annoying :-) please help , thank you in advance

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  • Deterministic and non uniform long string generation from seed

    - by Limonup
    I had this weird idea for an encryption that I wanted to try out, it may be bad, and it may have done before, but I'm just doing it for fun. The short version of the question is: Is it possible to generate a long, deterministic and non-uniformly distributed string/sequence of numbers from a small seed? Long(er) version: I was thinking to encrypt a text by changing encoding. The new encoding would be generated via Huffman algorithm. To work well, the Huffman algorithm would need a fairly long text with non uniform distribution. Then characters can have different bit-lengths which would be the primary strength of this encryption. The problem is that its impractical to enter in/remember a long text each time you want to decrypt the text. So I was wondering if it was possible to generate a text from password seed? It doesn't matter what the text is, as long as it has non uniform distribution of characters and that the exact same sequence can be recreated each time you give it the same seed. Preferably, are there any functions/extensions in Python that can do this? EDIT: To expand on the "strength" of varying bit length: if I have a string "test", ASCII values 116, 101, 115, 116, which gives bit values of 1110100 1100101 1110011 1110100 Then, say my Huffman algorithm generates encoding like t = 101 e = 1100111 s = 10001 The final string is 101 1100111 10001 101, if we encode this back to ASCII, we get 1011100 1111000 1101000, which is 3 entirely different characters. Obviously its impossible to perform any kind of frequency analysis or something like that on this.

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  • Generic dataset handling library

    - by Pep.
    Hello, I want to build a generic Perl module for handling and analysing biomedical character separated datasets and which can, most certain, be used on any kind of datasets that contain a mixture of categorical (A,B,C,..) and continuous (1.2,3,881..) and identifier (XXX1,XXX2...). The plan is to have people initialize the module and then use some arguments to point to the data file(s), the place were the analysis reports should be placed and the structure of the data. By structure of data I mean which variable is in which place and its name/type. And this is where I need some enlightenment. I am baffled how to do this in a clean way. Obviously, having people create a simple schema file, be it XML or some other format would be the cleanest but maybe not all people enjoy doing something like this. The solutions I can think of are: Create a configuration file in XML or similar and with a prespecified format. Pass the information during initialization of the module. Use the first row of the data as headers and try to guess types (ouch) Surely there must be a "canonical" way of doing this that is also usable and efficient. Thanks p.

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  • html body inside if condition

    - by gautam
    Hi, i have two different bodies for different conditions. can i do like this.... <% if(yes) %> <body onload="JavaScript:timedRefresh(120000);"> <% } else { %> <body> <% } %> Please help me... Thanks in advance.. I want to compare my title in if condition how can i do??? currently i am doing like this: <head> <title> <tiles:getAsString name="title"/> </title> </head> <% if(%><tiles:getAsString name="title"/><%.equals("Trade Confirmation Analysis Screen")) %> <body onload="JavaScript:timedRefresh(120000);"> <%else { %> <body> <% } %> Its giving me error..Unable to compile class for JSP:

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  • Which to use, XMP or RDF?

    - by zotty
    What's the difference between RDF and XMP? From what I can tell, XMP is derived from RDF... so what does it offer that RDF doesn't? My particular situation is this: I've got some images which need tagging with details of how an experiment was performed, and what sort of data analysis has been performed on the images. A colleague of mine is pushing for XMP, but he's thinking of the images as photos - they're not really, they're just bits of data. From what I've seen (mainly by opening images in notepad++) the XMP data looks very similar to RDF - even so far as using RDF in the tag names (e.g. <rdf:Seq>). I'd like this data to be usable by other people who use similar instruments for similar experiments, so creating a mini standard (schema?) seems like the way to go. Apologies for the lack of fundemental understanding - I'm a Doctor, not a programmer! If it makes any difference, the language of choice will be C#. Edit for more information: First off, thanks for the excellent replies - thinking of XMP as a vocabulary for RDF makes things a lot clearer. The sort of data I'll be storing wont be avaliable in any of the pre-defined sets. It'll detail experimental set ups, locations and results. I think using RDF is the way to go.

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  • Webfaction apache + mod_wsgi + django configuration issue

    - by Dmitry Guyvoronsky
    A problem that I stumbled upon recently, and, even though I solved it, I would like to hear your opinion of what correct/simple/adopted solution would be. I'm developing website using Django + python. When I run it on local machine with "python manage.py runserver", local address is http://127.0.0.1:8000/ by default. However, on production server my app has other url, with path - like "http://server.name/myproj/" I need to generate and use permanent urls. If I'm using {% url view params %}, I'm getting paths that are relative to / , since my urls.py contains this urlpatterns = patterns('', (r'^(\d+)?$', 'myproj.myapp.views.index'), (r'^img/(.*)$', 'django.views.static.serve', {'document_root': settings.MEDIA_ROOT + '/img' }), (r'^css/(.*)$', 'django.views.static.serve', {'document_root': settings.MEDIA_ROOT + '/css' }), ) So far, I see 2 solutions: modify urls.py, include '/myproj/' in case of production run use request.build_absolute_uri() for creating link in views.py or pass some variable with 'hostname:port/path' in templates Are there prettier ways to deal with this problem? Thank you. Update: Well, the problem seems to be not in django, but in webfaction way to configure wsgi. Apache configuration for application with URL "hostname.com/myapp" contains the following line WSGIScriptAlias / /home/dreamiurg/webapps/pinfont/myproject.wsgi So, SCRIPT_NAME is empty, and the only solution I see is to get to mod_python or serve my application from root. Any ideas?

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  • Are functional programming languages good for practical tasks?

    - by Clueless
    It seems to me from my experimenting with Haskell, Erlang and Scheme that functional programming languages are a fantastic way to answer scientific questions. For example, taking a small set of data and performing some extensive analysis on it to return a significant answer. It's great for working through some tough Project Euler questions or trying out the Google Code Jam in an original way. At the same time it seems that by their very nature, they are more suited to finding analytical solutions than actually performing practical tasks. I noticed this most strongly in Haskell, where everything is evaluated lazily and your whole program boils down to one giant analytical solution for some given data that you either hard-code into the program or tack on messily through Haskell's limited IO capabilities. Basically, the tasks I would call 'practical' such as Aceept a request, find and process requested data, and return it formatted as needed seem to translate much more directly into procedural languages. The most luck I have had finding a functional language that works like this is Factor, which I would liken to a reverse-polish-notation version of Python. So I am just curious whether I have missed something in these languages or I am just way off the ball in how I ask this question. Does anyone have examples of functional languages that are great at performing practical tasks or practical tasks that are best performed by functional languages?

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  • Loading enumerations from database

    - by Mosh
    Hello, I have a problem with mapping .NET enumerations to database tables. Imagine I have a table called Statuses with the following values: StatusID | Name 1 Draft 2 Ready ... ... In the application layer, I can either use a Repository to get all Statuses as an IList object. However, the problem with this approach is that I cannot reference a certain status in my business logic. For example, how can I implement something like this? if (myObject.Status is Ready) do this else if (myObject.Status is Draft) do that... Since the statuses are loaded dynamically, I cannot tell for sure what particular Status object in the List represents the Draft or Ready status. Alternatively, I could just use an enumeration like public enum Statuses { Draft, Ready }; Then I could easily use an enumeration in my business logic. if (myObject.Status == Statuses.Draft) // do something... However, the problem with this approach is that every time the user wants to modify the list of Statuses (adding a new status, or renaming an existing status) the application has to be re-compiled. We cannot load the statuses dynamically from the database. Has anyone else come across a similar situation? Any solutions/patterns? Cheers, Mosh

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  • Raw types and subtyping

    - by Dmitrii
    We have generic class SomeClass<T>{ } We can write the line: SomeClass s= new SomeClass<String>(); It's ok, because raw type is supertype for generic type. But SomeClass<String> s= new SomeClass(); is correct to. Why is it correct? I thought that type erasure was before type checking, but it's wrong. From Hacker's Guide to Javac When the Java compiler is invoked with default compile policy it performs the following passes: parse: Reads a set of *.java source files and maps the resulting token sequence into AST-Nodes. enter: Enters symbols for the definitions into the symbol table. process annotations: If Requested, processes annotations found in the specified compilation units. attribute: Attributes the Syntax trees. This step includes name resolution, type checking and constant folding. flow: Performs data ow analysis on the trees from the previous step. This includes checks for assignments and reachability. desugar: Rewrites the AST and translates away some syntactic sugar. generate: Generates Source Files or Class Files. Generic is syntax sugar, hence type erasure invoked at 6 pass, after type checking, which invoked at 4 pass. I'm confused.

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  • What can cause my code to run slower when the server JIT is activated?

    - by durandai
    I am doing some optimizations on an MPEG decoder. To ensure my optimizations aren't breaking anything I have a test suite that benchmarks the entire codebase (both optimized and original) as well as verifying that they both produce identical results (basically just feeding a couple of different streams through the decoder and crc32 the outputs). When using the "-server" option with the Sun 1.6.0_18, the test suite runs about 12% slower on the optimized version after warmup (in comparison to the default "-client" setting), while the original codebase gains a good boost running about twice as fast as in client mode. While at first this seemed to be simply a warmup issue to me, I added a loop to repeat the entire test suite multiple times. Then execution times become constant for each pass starting at the 3rd iteration of the test, still the optimized version stays 12% slower than in the client mode. I am also pretty sure its not a garbage collection issue, since the code involves absolutely no object allocations after startup. The code consists mainly of some bit manipulation operations (stream decoding) and lots of basic floating math (generating PCM audio). The only JDK classes involved are ByteArrayInputStream (feeds the stream to the test and excluding disk IO from the tests) and CRC32 (to verify the result). I also observed the same behaviour with Sun JDK 1.7.0_b98 (only that ist 15% instead of 12% there). Oh, and the tests were all done on the same machine (single core) with no other applications running (WinXP). While there is some inevitable variation on the measured execution times (using System.nanoTime btw), the variation between different test runs with the same settings never exceeded 2%, usually less than 1% (after warmup), so I conclude the effect is real and not purely induced by the measuring mechanism/machine. Are there any known coding patterns that perform worse on the server JIT? Failing that, what options are available to "peek" under the hood and observe what the JIT is doing there?

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  • How to replace pairs of strings in two files to identical IDs?

    - by Péter Török
    Sorry if the title is not very intelligible, I couldn't come up with anything better. Hopefully my explanation is clear enough: I have a pair of rather large log files with very similar content, except that some strings are different between the two. A couple of examples: UnifiedClassLoader3@19518cc | UnifiedClassLoader3@d0357a JBossRMIClassLoader@13c2d7f | JBossRMIClassLoader@191777e That is, wherever the first file contains UnifiedClassLoader3@19518cc, the second contains UnifiedClassLoader3@d0357a, and so on. [Update] There are about 40 distinct pairs of such identifiers.[/Update] I want to replace these with identical IDs so that I can spot the really important differences between the two files. I.e. I want to replace all occurrences of both UnifiedClassLoader3@19518cc in file1 and UnifiedClassLoader3@d0357a in file2 with UnifiedClassLoader3@1; all occurrences of both JBossRMIClassLoader@13c2d7f in file1 and JBossRMIClassLoader@191777e in file2 with JBossRMIClassLoader@2 etc. Using the Cygwin shell, so far I managed to list all different identifiers occurring in one of the files with grep -o -e 'ClassLoader[0-9]*@[0-9a-f][0-9a-f]*' file1.log | sort | uniq However, now the original order is lost, so I don't know which is the pair of which ID in the other file. With grep -n I can get the line number, so the sort would preserve the order of appearance, but then I can't weed out the duplicate occurrences. Unfortunately grep can not print only the first match of a pattern. I figured I could save the list of identifiers produced by the above command into a file, then iterate over the patterns in the file with grep -n | head -n 1, concatenate the results and sort them again. The result would be something like 2 ClassLoader3@19518cc 137 ClassLoader@13c2d7f 563 ClassLoader3@1267649 ... Then I could (either manually or with sed itself) massage this into a sed command like sed -e 's/ClassLoader3@19518cc/ClassLoader3@2/g' -e 's/ClassLoader@13c2d7f/ClassLoader@137/g' -e 's/ClassLoader3@1267649/ClassLoader3@563/g' file1.log > file1_processed.log and similarly for file2. However, before I start, I would like to verify that my plan is the simplest possible working solution to this. Is there any flaw in this approach? Is there a simpler way?

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  • What do you do when your boss doesn't care about code quality?

    - by Chad Johnson
    My boss (a proprietor) is a developer like me. He comes, however, from a C background and severely lacks knowledge of the benefits of proper object-oriented design. That, or he simply ignores them. So my co-worker developed this feature prototype in a week, and it's not release-ready--at least not from a good code standpoint. It works; it does the job--but it'sa freaking prototype. It's totally not scalable. My boss wants to wow clients and "just get the feature out." I understand that. But, we could take two weeks and finish this shit up, or we could take three and finish this shit up AND do it so that it's scalable. I just KNOW we are going to want to add onto this feature in the coming months, and then, a customer is going to "need it in a week," and so even though we've agreed to refactor when we want to add onto the feature, IT WILL NEVER HAPPEN! This ALWAYS happens. I'm the code quality assurance guy, but my boss seems to see me as a radical and thinks I just waste time, whereas I actually am trying to follow good, known solid design patterns. He just wants his stinking feature though, and he doesn't want to spend the time or money to do things well. He pretty much listens to what I have to say, and then he ultimately just makes the decision to take the shortest path (which cuts corners a lot). I often develop large, important features for our software. THOSE THINGS TAKE TIME! They're not happy with the time it's taken with past projects, though, but the features I've put in all work really damn well and are very scalable. How do you all deal with this kind of situation?

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  • How to classify NN/NNP/NNS obtained from POS tagged document as a product feature

    - by Shweta .......
    I'm planning to perform sentiment analysis on reviews of product features (collected from Amazon dataset). I have extracted review text from the dataset and performed POS tagging on that. I'm able to extract NN/NNP as well. But my doubt is how do I come to know that extracted words classify as features of the products? I know there are classifiers in nltk but I don't know how I should use it for my project. I'm assuming there are 2 ways of finding whether the extracted word is a product feature or not. One is to compare with a bag of words and find out if my word exists in that. Doubt: How do I create/get bag of words? Second way is to implement some kind of apriori algorithm to find out frequently occurring words as features. I would like to know which method is good and how to go about implementing it. Some pointers to available softwares or code snippets would be helpful! Thanks!

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  • Should a Trim method generally in the Data Access Layer or with in the Domain Layer?

    - by jpierson
    I'm dealing with a database that contains data with inconsistencies such as white leading and trailing white space. In general I see a lot of developers practice defensive coding by trimming almost all strings that come from the database that may have been entered by a user at some point. In my oppinoin it is better to do such formating before data is persisted so that it is done only once and then the data can be in a consistent and reliable state. Unfortunatley this is not the case however which leads me to the next best solution, using a Trim method. If I trim all data as part of my data access layer then I don't have to concern myself with defensive trimming within the business objects of my domain layer. If I instead put the trimming responsibility in my business objects, such as with set accessors of my C# properties, I should get the same net results however the trim will be operating on all values assigned to my business objects properties not just the ones that come from the inconsistent database. I guess as a somewhat philisophical question that may determine the answer I could ask "Should the domain later be responsible for defensive/coercive formatting of data?" Would it make sense to have a set accessor for a PhoneNumber property on a business object accept a unformatted or formatted string and then attempt to format it as required or should this responsibility be pushed to the presentation and data access layers leaving the domain layer more strict in the type of data that it will accept? I think this may be the more fundamental question. Update: Below are a few links that I thought I should share about the topic of data cleansing. Information service patterns, Part 3: Data cleansing pattern LINQ to SQL - Format a string before saving? How to trim values using Linq to Sql?

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