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  • GA written in Java

    - by EnderMB
    I am attempting to write a Genetic Algorithm based on techniques I had picked up from the book "AI Techniques for Game Programmers" that uses a binary encoding and fitness proportionate selection (also known as roulette wheel selection) on the genes of the population that are randomly generated within the program in a two-dimensional array. I recently came across a piece of pseudocode and have tried to implement it, but have come across some problems with the specifics of what I need to be doing. I've checked a number of books and some open-source code and am still struggling to progress. I understand that I have to get the sum of the total fitness of the population, pick a random number between the sum and zero, then if the number is greater than the parents to overwrite it, but I am struggling with the implementation of these ideas. Any help in the implementation of these ideas would be very much appreciated as my Java is rusty.

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  • Getting a UDP socket program in Python to accept messages from a Syslog client?

    - by Elvar
    I'm trying to write a Syslog listener and so far so good on getting it to accept incoming messages through TCP but I also want UDP to function. This is the UDP server code I'm using, which works using a python client app. I also have another app which also works just using the python client app. # Server program # UDP VERSION from socket import * # Set the socket parameters host = "localhost" port = 514 buf = 1024 addr = (host,port) # Create socket and bind to address UDPSock = socket(AF_INET,SOCK_DGRAM) UDPSock.bind(addr) # Receive messages while 1: data,addr = UDPSock.recvfrom(buf) if not data: print "Client has exited!" break else: print "\nReceived message '", data,"'" # Close socket UDPSock.close() Using this code I can send to the server and have it display the code. # Client program from socket import * # Set the socket parameters host = "localhost" port = 514 buf = 1024 addr = (host,port) # Create socket UDPSock = socket(AF_INET,SOCK_DGRAM) def_msg = "===Enter message to send to server==="; print "\n",def_msg # Send messages while (1): data = raw_input('>> ') if not data: break else: if(UDPSock.sendto(data,addr)): print "Sending message '",data,"'....." # Close socket UDPSock.close() I have tried the Kiwi Syslog Message Generator and Snare to send syslog messages to the UDP server and nothing comes up. Could someone help me understand?

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  • Why won't this SQL CAST work?

    - by Kev
    I have a nvarchar(50) column in a SQL Server 2000 table defined as follows: TaskID nvarchar(50) NULL I need to fill this column with some random SQL Unique Identifiers (I am unable to change the column type to uniqueidentifier). I tried this: UPDATE TaskData SET TaskID = CAST(NEWID() AS nvarchar) but I got the following error: Msg 8115, Level 16, State 2, Line 1 Arithmetic overflow error converting expression to data type nvarchar. I also tried: UPDATE TaskData SET TaskID = CAST(NEWID() AS nvarchar(50)) but then got this error: Msg 8152, Level 16, State 6, Line 1 String or binary data would be truncated. I don't understand why this doesn't work but this does: DECLARE @TaskID nvarchar(50) SET @TaskID = CAST(NEW() AS nvarchar(50)) I also tried CONVERT(nvarchar, NEWID()) and CONVERT(nvarchar(50), NEWID()) but got the same errors.

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  • How to check value of stored procedure output parameter

    - by Anna T
    I have a stored procedure that: A. inserts some rows into a "table variable" based on some joins B. selects all values from column x from that table into a string with comma separated values C. selects all from the "table variable" If I execute the procedure like this: EXEC CatalogGetFilmDetails2 2,111111; a table is returned as instructed per step C above. How can I execute it so that also the output parameter value is displayed? (see point B above). I need to check if it's calculated properly. And since the second parameter is of output type, meaning it's calculated inside the procedure, why is it mandatory to specify a value for it when executing the procedure? I normally use a random value for it, it anyway doesn't matter/impact the result. On the other hand if I try to execute it without the output parameter, it returns an error) Thank you very much! This is how the procedure starts: CREATE PROCEDURE CatalogGetFilmDetails2 (@FilmID int, @CommaSepString VARCHAR(50) OUTPUT) AS And this is how @CommaSepString is calculated: SELECT @CommaSepString = STUFF((SELECT ', ' + Categ FROM @Filme1 FOR XML PATH('')), 1,1,'')

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  • Integration (math) in C++

    - by Chris Thompson
    Hi all, I'm looking for a library to find the integral of a given set of random data (rather than a function) in C++ (or C, but preferably C++). There is another question asking about integration in C but the answers discuss more how to integrate a function (I think...). I understand that this can be done simply by calculating the area under the line segment between each pair of points from start to finish, but I'd rather not reinvent the wheel if this has already been done. I apologize in advance if this is a duplicate; I searched pretty extensively to no avail. My math isn't as strong as I'd like it so it's entirely possible I'm using the wrong terminology. Thanks in advance for any help! Chris

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  • How to find a duplicate element in an array of shuffled consecutive integers?

    - by SysAdmin
    I recently came across a question somewhere Suppose you have an array of 1001 integers. The integers are in random order, but you know each of the integers is between 1 and 1000 (inclusive). In addition, each number appears only once in the array, except for one number, which occurs twice. Assume that you can access each element of the array only once. Describe an algorithm to find the repeated number. If you used auxiliary storage in your algorithm, can you find an algorithm that does not require it? what i am interested to know is the second part. i.e without using auxiliary storage . do you have any idea?

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  • how to click on a button in python

    - by Ciobanu Alexandru
    Trying to build some bot for clicking "skip-ad" button on a page. So far, i manage to use Mechanize to load a web-driver browser and to connect to some page but Mechanize module do not support js directly so now i need something like Selenium if i understand correct. I am also a beginner in programming so please be specific. How can i use Selenium or if there is any other solution, please explain details. This is the inner html code for the button: <a id="skip-ad" class="btn btn-inverse" onclick="open_url('http://imgur.com/gallery/tDK9V68', 'go'); return false;" style="font-weight: bold; " target="_blank" href="http://imgur.com/gallery/tDK9V68"> … </a> And this is my source so far: #!/usr/bin/python # FILENAME: test.py import mechanize import os, time from random import choice, randrange prox_list = [] #list of common UAS to apply to each connection attempt to impersonate browsers user_agent_strings = [ 'Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1468.0 Safari/537.36', 'Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.1) Gecko/2008071615 Fedora/3.0.1-1.fc9 Firefox/3.0.1', 'Opera/9.80 (Windows NT 6.0) Presto/2.12.388 Version/12.14', 'Opera/9.80 (Macintosh; Intel Mac OS X 10.6.8; U; fr) Presto/2.9.168 Version/11.52', 'Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:23.0) Gecko/20131011 Firefox/23.0', 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; Media Center PC 6.0; InfoPath.3; MS-RTC LM 8; Zune 4.7', 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0; .NET CLR 2.0.50727; SLCC2; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; Zune 4.0; Tablet PC 2.0; InfoPath.3; .NET4.0C; .NET4.0E)', 'Mozilla/5.0 (compatible; MSIE 10.6; Windows NT 6.1; Trident/5.0; InfoPath.2; SLCC1; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET CLR 2.0.50727) 3gpp-gba UNTRUSTED/1.0', 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.0; Trident/5.0; chromeframe/11.0.696.57)', 'Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; InfoPath.1; SV1; .NET CLR 3.8.36217; WOW64; en-US)', 'Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; GTB7.4; InfoPath.2; SV1; .NET CLR 3.3.69573; WOW64; en-US)' ] def load_proxy_list(target): #loads and parses the proxy list file = open(target, 'r') count = 0 for line in file: prox_list.append(line) count += 1 print "Loaded " + str(count) + " proxies!" load_proxy_list('proxies.txt') #for i in range(1,(len(prox_list) - 1)): # depreceated for overloading for i in range(1,30): br = mechanize.Browser() #pick a random UAS to add some extra cover to the bot br.addheaders = [('User-agent', choice(user_agent_strings))] print "----------------------------------------------------" #This is bad internet ethics br.set_handle_robots(False) #choose a proxy proxy = choice(prox_list) br.set_proxies({"http": proxy}) br.set_debug_http(True) try: print "Trying connection with: " + str(proxy) #currently using: BTC CoinURL - Grooveshark Broadcast br.open("http://cur.lv/4czwj") print "Opened successfully!" #act like a nice little drone and view the ads sleep_time_on_link = randrange(17.0,34.0) time.sleep(sleep_time_on_link) except mechanize.HTTPError, e: print "Oops Request threw " + str(e.code) #future versions will handle codes properly, 404 most likely means # the ad-linker has noticed bot-traffic and removed the link # or the used proxy is terrible. We will either geo-locate # proxies beforehand and pick good hosts, or ditch the link # which is worse case scenario, account is closed because of botting except mechanize.URLError, e: print "Oops! Request was refused, blacklisting proxy!" + str(e) prox_list.remove(proxy) del br #close browser entirely #wait between 5-30 seconds like a good little human sleep_time = randrange(5.0, 30.0) print "Waiting for %.1f seconds like a good bot." % (sleep_time) time.sleep(sleep_time)

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  • Retrieve only the superclass from a class hierarchy

    - by user1792724
    I have an scenario as the following: @Entity @Table(name = "ANIMAL") @Inheritance(strategy = InheritanceType.JOINED) public class Animal implements Serializable { @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "S_ANIMAL") @SequenceGenerator(name = "S_ANIMAL", sequenceName = "S_ANIMAL", allocationSize = 1) public int getNumero() { return numero; } public void setNumero(int numero) { this.numero = numero; } . . . } and as the subclass: @Entity @Table(name = "DOG") public class Dog extends Animal { private static final long serialVersionUID = -7341592543130659641L; . . . } I have a JPA Select statement like this: SELECT a FROM Animal a; I'm using Hibernate 3.3.1 As I can see the framework retrieves instances of Animal and also of Dog using a left outer join. Is there a way to Select only the "part" Animal? I mean, the previous Select will get all the Animals, those that are only Animals but not Dogs and those that are Dogs. I want them all, but in the case of Dogs I want to only retrieve the "Animal part" of them. I found the @org.hibernate.annotations.Entity(polymorphism = PolymorphismType.EXPLICIT) but as I could see this only works if Animal isn't an @Entity. Thanks a lot.

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  • mmap() for large file I/O?

    - by Boatzart
    I'm creating a utility in C++ to be run on Linux which can convert videos to a proprietary format. The video frames are very large (up to 16 megapixels), and we need to be able to seek directly to exact frame numbers, so our file format uses libz to compress each frame individually, and append the compressed data onto a file. Once all frames are finished being written, a journal which includes meta data for each frame (including their file offsets and sizes) is written to the end of the file. I'm currently using ifstream and ofstream to do the file i/o, but I am looking to optimize as much as possible. I've heard that mmap() can increase performance in a lot of cases, and I'm wondering if mine is one of them. Our files will be in the tens to hundreds of gigabytes, and although writing will always be done sequentially, random access reads should be done in constant time. Any thoughts as to whether I should investigate this further, and if so does anyone have any tips for things to look out for? Thanks!

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  • NSString simple pattern matching

    - by SirRatty
    Hi all, Mac OS 10.6, Cocoa project, 10.4 compatibility required. (Please note: my knowledge of regex is quite slight) I need to parse NSStrings, for matching cases where the string contains an embedded tag, where the tag format is: [xxxx] Where xxxx are random characters. e.g. "The quick brown [foxy] fox likes sox". In the above case, I need to grab the string "foxy". (Or nil if no tag is found.) Each string will only have one tag, and the tag can appear anywhere within the string, or may not appear at all. Could someone please help with a way to do that, preferably without having to include another library such as RegexKit. Thank you for any help.

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  • Reading a client's header from Python CGI script?

    - by jawonlee
    I'm writing a very simple web service, written in Python and run as CGI on an Apache server. According to Python docs (somewhere... I forgot where), I can use sys.stdin to read the data POSTed by a random client, and this has been working fine. However, I would like to be able to read the HTTP header information as well - incoming IP, user agent, and so on. I'd also like to keep it very simple for now, by using only Python libraries (so no mod-python). How do I do this?

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  • Some process does ICMP port scan on my OSX box and I am afraid my Mac got a virus

    - by Jamgold
    I noticed that my 10.6.6 box has some process send out ICMP messages to "random" hosts, which concerns me a lot. when doing a tcpdump icmp I see a lot of the following 15:41:14.738328 IP macpro bzq-109-66-184-49.red.bezeqint.net: ICMP macpro udp port websm unreachable, length 36 15:41:15.110381 IP macpro 99-110-211-191.lightspeed.sntcca.sbcglobal.net: ICMP macpro udp port 54045 unreachable, length 36 15:41:23.458831 IP macpro 188.122.242.115: ICMP macpro udp port websm unreachable, length 36 15:41:23.638731 IP macpro 61.85-200-21.bkkb.no: ICMP macpro udp port websm unreachable, length 36 15:41:27.329981 IP macpro c-98-234-88-192.hsd1.ca.comcast.net: ICMP macpro udp port 54045 unreachable, length 36 15:41:29.349586 IP macpro c-98-234-88-192.hsd1.ca.comcast.net: ICMP macpro udp port 54045 unreachable, length 36 I got suspicious when my router notified me about a lot of ICMP messages that don't get a response Does anyone know how to trace which process (or worse kernel module) might be responsible for this? I rebooted and logged in with a virgin user account and tcpdump showed the same results. Any dtrace magic welcome. Thanks in advance

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  • JTextArea thread safe?

    - by Dhaivat Pandya
    Hello everyone, I have some code that does some initialization (including making a JTextArea object), starts three seperate threads, and then these threads try to update the JTextArea (i.e. append() to it), but its not working at all. Nothing shows up on the JTextArea (however, during the initialzation, I print some test lines onto it, and that works fine). What's going on? How can I fix this? Also, each of those threads sleeps a random amount of time every time it has to update the JTextArea. Sorry I haven't provided any code, its all spread out over several files.

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  • Are there any widely-agreed upon guidelines for rating your language knowledge on a scale?

    - by DVK
    The question was imagined after a co-worker was complaining for an hour about some guy who could not answer basic Java questions on an interview after self-identifying himself as "8 out of 10" on Java. While that was an obvious fib, I personally always had major trouble defining my specific language skills on a sliding scale unless I'm given specific guidelines (remember 40 standard libraries by heart? Able to solve 10 random Project Euler problems in <30 mins each? Can write implementation of A, B and C data-structures from scratch in 30 mins? Know 30% of standard? Can answer 50% of questions on StackOverflow pertaining to the language?) So, I was wondering - is there some sort of commonly accepted methodology for translating such tangible benchmarks into "rate yourself on a language between 1-10"? "Kernighan gets an A, God gets a B, everyone else gets C and less" type jokes are not helpful :)

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  • R counting the occurrences of similar rows of data frame

    - by Matt
    I have data in the following format called DF (this is just a made up simplified sample): eval.num, eval.count, fitness, fitness.mean, green.h.0, green.v.0, offset.0 random 1 1 1500 1500 100 120 40 232342 2 2 1000 1250 100 120 40 11843 3 3 1250 1250 100 120 40 981340234 4 4 1000 1187.5 100 120 40 4363453 5 1 2000 2000 200 100 40 345902 6 1 3000 3000 150 90 10 943 7 1 2000 2000 90 90 100 9304358 8 2 1800 1900 90 90 100 284333 However, the eval.count column is incorrect and I need to fix it. It should report the number of rows with the same values for (green.h.0, green.v.0, and offset.0) by only looking at the previous rows. The example above uses the expected values, but assume they are incorrect. How can I add a new column (say "count") which will count all previous rows which have the same values of the specified variables? I have gotten help on a similar problem of just selecting all rows with the same values for specified columns, so I supposed I could just write a loop around that, but it seems inefficient to me.

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  • rails 3.0.3 - ActiveRecord::Relation, undefined method error

    - by brg
    I am having this unexplained ActiveRecord::Relation, undefined method error . I don't know why, since my model association are well defined and the event table has the foreign keys for the user table. I tried using this fix but it failed: Rails 3 ActiveRecord::Relation random associations behavior event.rb class Event < ActiveRecord::Base belongs_to :user attr_accessible :event_name, :Starts_at, :finish, :tracks end user.rb class User < ActiveRecord::Base has_many :events, :dependent = :destroy attr_accessible :name, :event_attributes accepts_nested_attributes_for :events, :allow_destroy = true end schema.rb ActiveRecord::Schema.define(:version = 20101201180355) do create_table "events", :force = true do |t| t.string "event_name" t.string "tracks" t.datetime "starts_at" t.datetime "finish" t.datetime "created_at" t.datetime "updated_at" t.integer "user_id" end end error message NoMethodError in Users#index undefined method `events' for # Extracted source (around line #10): 7: <%= sortable "Tracks" % 8: 10: <% @users.events.each do |event| % 11: <% debugger % 12: 13: <%= event.starts_at % Trace of template inclusion: app/views/users/index.html.erb Rails.root: C:/rails_project1/events_manager Application Trace | Framework Trace | Full Trace app/views/users/_event_user.html.erb:10:in _app_views_users__event_user_html_erb__412443848_34308540_1390678' app/views/users/index.html.erb:7:in_app_views_users_index_html_erb___603337143_34316016_0'

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  • Why does the VBA Editor open on its own sometimes?

    - by Kevin Finn
    I've created a small script in Outlook 2003 VBA that watches for new appointments, and sets them to tentative and no reminder as I create them. However, I now find that seemingly at random, the VBA editor will open itself. It doesn't happen when I actually use the new script, but it did happen this morning when I un-hibernated my laptop, for example. The editor doesn't pop up any runtime errors or highlight any lines in the script, it's just there as if I had pressed Alt-F11 to launch it. Sometimes I close other apps and see that it's been sitting back there for a while. This behavior has only been occurring since I created this new script. Any ideas why this would occur? Thanks!

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  • Regex in Flex 3: How to Wrap Quotations Around a Dynamic String?

    - by Laxmidi
    Hi, I need some Regex help. I need to find beacon_ followed by an alphanumeric code and then wrap it in quotation marks. For something static, like the example, below it's straight forward. myReturn = myReturn.replace( 'id=beacon_80291ee9b3', 'id="beacon_80291ee9b3"'); But, my problem is that the part after beacon is a random alphanumeric code. (However, it is always the same length). For example, the beacon part could be: beacon_c8ac873136 beacon_dc83b5953e beacon_7a910d03d8 etc. The haystack that I'll search will look like: myReturn = "blah blah id=beacon_80291ee9b3 blah blah"; Thanks. -Laxmidi

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  • How do we achieve "substring-match" under O(n) time?

    - by Pacerier
    I have an assignment that requires reading a huge file of random inputs, for example: Adana Izmir Adnan Menderes Apt Addis Ababa Aden ADIYAMAN ALDAN Amman Marka Intl Airport Adak Island Adelaide Airport ANURADHAPURA Kodiak Apt DALLAS/ADDISON Ardabil ANDREWS AFB etc.. If I specify a search term, the program is supposed to find the lines whereby a substring occurs. For example, if the search term is "uradha", the program is supposed to show ANURADHAPURA. If the search term is "airport", the program is supposed to show Amman Marka Intl Airport, Adelaide Airport A quote from the assignment specs: "You are to program this application taking efficiency into account as though large amounts of data and processing is involved.." I could easily achieve this functionality using a loop but the performance would be O(n). I was thinking of using a trie but it seems to only work if the substring starts from index 0. I was wondering what solutions are there which gives a performance better than O(n)?

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  • Getting all objects with a certain element inside a collection of strings with criteria API.

    - by Jens Jansson
    Hey. I'm trying to build a Hibernate Criteria query to find entities that have a specific element inside a collection. We can take as an example a Book -object that looks like this: public class Book { private Long id; private String title; private Set<String> authors = new HashSet<String>(); } The entity is mapped like this: <class name="Book" table="Book"> <id name="id" column="BOOK_ID"> <generator class="native"/> </id> <property name="title"/> <set name="authors" table="Book_Authors"> <key column="BOOK_ID"/> <element type="string" column="AUTHORS"/> </set> </class> Now I would like to find out which books are written by Matt. With pure SQL I can do a query like this: String author = "Matt"; String query = "SELECT * FROM Book " + "WHERE BOOK_ID IN " + "(SELECT BOOK_ID FROM Book_Authors " + "WHERE authors = :author )"; List<Book> result = session.createSQLQuery(query) .addEntity(Book.class) .setParameter("author", author) .list(); This works all good and well, and I get out all books that Matt has been a part of writing. The project I work in, however, uses the Criteria API instead of raw SQL, and I haven't found a way to express the same query in that form. I've taken a look on the Restrictions API and the closest I've found is Restions.in(propertyName, collection) but that works the other way around (one value in object, many values to match against). Any ideas?

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  • Entity Framework in layered architecture

    - by Kamyar
    I am using a layered architecture with the Entity Framework. Here's What I came up with till now (All the projects Except UI are class library): Entities: The POCO Entities. Completely persistence ignorant. No Reference to other projects. Generated by Microsoft's ADO.Net POCO Entity Generator. DAL: The EDMX (Entity Model) file with the context class. (t4 generated). References: Entities BLL: Business Logic Layer. Will implement repository pattern on this layer. References: Entities, DAL. This is where the objectcontext gets populated: var ctx=new DAL.MyDBEntities(); UI: The presentation layer: ASP.NET website. References: Entities, BLL + a connection string entry to entities in the config file (question #2). Now my three questions: Is my layer discintion approach correct? In my UI, I access BLL as follows: var customerRep = new BLL.CustomerRepository(); var Customer = customerRep.GetByID(myCustomerID); The problem is that I have to define the entities connection string in my UI's web.config/app.config otherwise I get a runtime exception. IS defining the entities connectionstring in UI spoils the layers' distinction? Or is it accesptible in a muli layered architecture. Should I take any additional steps to perform chage tracking, lazy loading, etc (by etc I mean the features that Entity Framework covers in a conventional, 1 project, non POCO code generation)? Thanks and apologies for the lengthy question.

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  • EF 4 Self Tracking Entities does not work as expected.

    - by ashraf
    I am using EF4 Self Tracking Entities (VS2010 Beta 2 CTP 2 plus new T4 generator). But when I try to update entity information it does not update to database as expected. I setup 2 service calls. one for GetResource(int id) which return a resource object. the second call is SaveResource(Resource res); here is the code. public Resource GetResource(int id) { using (var dc = new MyEntities()) { return dc.Resources.Where(d => d.ResourceId == id).SingleOrDefault(); } } public void SaveResource(Resource res) { using (var dc = new MyEntities()) { dc.Resources.ApplyChanges(res); dc.SaveChanges(); // Nothing save to database. } } //Windows Console Client Calls var res = service.GetResource(1); res.Description = "New Change"; // Not updating... service.SaveResource(res); // does not change anything. It seems to me that ChangeTracker.State is always show as "Unchanged". anything wrong in this code?

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  • JavaScript on Android randomly stops working

    - by AndersWid
    Hi! I have an application that uses a WebView and a html-page with javascript functions. Randomly the JavaScript functions doesn't seem to be called. It works up to a random point (I have looked at this bug all day) can only be produced on hardware (HTC Legend) not on emulator. Basicly I'm using callback to javaScript whenever the user presses a button, these callbacks tell the html to redraw using javaScript functions. mHandler.post(new Runnable() { public void run() { mWebView.loadUrl("javascript:getDataLine()"); } }); The first line in this javaScript code is an alert that says that it has started, so that I can see that it's working. Settings alerts or console.log's everywhere won't help as it seems the problem is in the webview or in Android itself. I need a way to see what's going on in the background. Maybe see if a previous call failed and stalled the thread or something.

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  • NHibernate collections: many-to-many relationships

    - by Brad Heller
    I've got two models, a Product model and a ShoppingCart model. The ShoppingCart model has a collection of products as a property called Products (List). Here is the mapping for my ShoppingCart model. <class name="MyProject.ShoppingCart, MyProject" table="ShoppingCarts"> <id name="Id" column="Id"> <generator class="native" /> </id> <many-to-one name="Company" class="MyProject.Company, MyProject" column="CompanyId" /> <property name="ExternalId" column="GUID" generated="insert" /> <property name="Name" column="Name" /> <property name="Total" column="Total" /> <property name="CreationDate" column="CreationDate" generated="insert" /> <property name="UpdatedDate" column="UpdatedDate" generated="always" /> <bag name="Products" table="ShoppingCartContents" lazy="false"> <key column="ShoppingCartId" /> <many-to-many column="ProductId" class="MyProjectMyProject.Product, MyProject" fetch="join" /> </bag> </class> When I try to save to the DB, the ShoppingCart is saved, but the mapping rows in ShoppingCartContents aren't save, making me thing that there's an issue with the mapping. Where am I going wrong here?

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  • Efficient synchronization of querying an array of resources

    - by Erel Segal Halevi
    There is a list of N resources, each of them can be queried by at most a single thread at a time. There are serveral threads that need to do the same thing at approximately the same time: query each of the resources (each thread has a different query), in arbitrary order, and collect the responses. If each thread loops over the resources in the same order, from 0 to N-1, then they will probably have to wait for each other, which is not efficient. I thought of letting the threads loop over the resources in a random permutation, but this seems too complex and also not so efficient, for example, for 2 resources and 2 threads, in half the cases they will choose the same order and wait for each other. Is there a simple and more efficient way to solve this?

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