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  • Java RMI Proxy issue

    - by Antony Lewis
    i am getting this error : java.lang.ClassCastException: $Proxy0 cannot be cast to rmi.engine.Call at Main.main(Main.java:39) my abstract and call class both extend remote. call: public class Call extends UnicastRemoteObject implements rmi.engine.Abstract { public Call() throws Exception { super(Store.PORT, new RClient(), new RServer()); } public String getHello() { System.out.println("CONN"); return "HEY"; } } abstract: public interface Abstract extends Remote { String getHello() throws RemoteException; } this is my main: public static void main(String[] args) { if (args.length == 0) { try { System.out.println("We are slave "); InetAddress ip = InetAddress.getLocalHost(); Registry rr = LocateRegistry.getRegistry(ip.getHostAddress(), Store.PORT, new RClient()); Object ss = rr.lookup("FILLER"); System.out.println(ss.getClass().getCanonicalName()); System.out.println(((Call)ss).getHello()); } catch (Exception e) { e.printStackTrace(); } } else { if (args[0].equals("master")) { // Start Master try { RMIServer.start(); } catch (Exception e) { e.printStackTrace(); } } Netbeans says the problem is on line 39 which is System.out.println(((Call)ss).getHello()); the output looks like this: run: We are slave Connecting 10.0.0.212:5225 $Proxy0 java.lang.ClassCastException: $Proxy0 cannot be cast to rmi.engine.Call at Main.main(Main.java:39) BUILD SUCCESSFUL (total time: 1 second) i am running a master in cmd listening on port 5225.

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  • import csv file/excel into sql database asp.net

    - by kiev
    Hi everyone! I am starting a project with asp.net visual studio 2008 / SQL 2000 (2005 in future) using c#. The tricky part for me is that the existing DB schema changes often and the import files columns will all have to me matched up with the existing db schema since they may not be one to one match on column names. (There is a lookup table that provides the tables schema with column names I will use) I am exploring different ways to approach this, and need some expert advice. Is there any existing controls or frameworks that I can leverage to do any of this? So far I explored FileUpload .NET control, as well as some 3rd party upload controls to accomplish the upload such as SlickUpload but the files uploaded should be < 500mb Next part is reading of my csv /excel and parsing it for display to the user so they can match it with our db schema. I saw CSVReader and others but for excel its more difficult since I will need to support different versions. Essentially The user performing this import will insert and/or update several tables from this import file. There are other more advance requirements like record matching but and preview of the import records, but I wish to get through understanding how to do this first. Update: I ended up using csvReader with LumenWorks.Framework for uploading the csv files.

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  • Handling close-to-impossible collisions on should-be-unique values

    - by balpha
    There are many systems that depend on the uniqueness of some particular value. Anything that uses GUIDs comes to mind (eg. the Windows registry or other databases), but also things that create a hash from an object to identify it and thus need this hash to be unique. A hash table usually doesn't mind if two objects have the same hash because the hashing is just used to break down the objects into categories, so that on lookup, not all objects in the table, but only those objects in the same category (bucket) have to be compared for identity to the searched object. Other implementations however (seem to) depend on the uniqueness. My example (that's what lead me to asking this) is Mercurial's revision IDs. An entry on the Mercurial mailing list correctly states The odds of the changeset hash colliding by accident in your first billion commits is basically zero. But we will notice if it happens. And you'll get to be famous as the guy who broke SHA1 by accident. But even the tiniest probability doesn't mean impossible. Now, I don't want an explanation of why it's totally okay to rely on the uniqueness (this has been discussed here for example). This is very clear to me. Rather, I'd like to know (maybe by means of examples from your own work): Are there any best practices as to covering these improbable cases anyway? Should they be ignored, because it's more likely that particularly strong solar winds lead to faulty hard disk reads? Should they at least be tested for, if only to fail with a "I give up, you have done the impossible" message to the user? Or should even these cases get handled gracefully? For me, especially the following are interesting, although they are somewhat touchy-feely: If you don't handle these cases, what do you do against gut feelings that don't listen to probabilities? If you do handle them, how do you justify this work (to yourself and others), considering there are more probable cases you don't handle, like a supernonva?

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  • Some questions about dotnetopenauth

    - by chobo2
    Hi I have a couple outstanding questions mainly reguarding twitter and facebook In the FacebookGraph class there are properties such as Id,name,etc. I am wondering how do I add to this list? Like what happens if I want a users hometown? I tried to add a property called hometown but it always is null. What should I store their id(1418) or the whole url(http://www.facebook.com/profile.php?id=1418) for lookup later in my db to grab their data and to see if they have an account with my site? Is it actually good to use this id as it seems like it is common knowledge. Can't someone just find the profile id or whatever and do a fake request on my site? how do you setup dotnetopenauth to deal with the case when a user goes to facebook and deletes access to my website. I know you can send a deauthorization code to your site and then delete their account but I don't know how to do that through dotnetopenauth Twitter Is it possible to do number 4 with twitter? Ajax Is it possible to make the openid stuff ajax? I don't see a sample anywhere in the dotnetopenauth samples.

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  • Model class for NSDictionary information with Lazy Loading

    - by samfu_1
    My application utilizes approx. 50+ .plists that are used as NSDictionaries. Several of my view controllers need access to the properties of the dictionaries, so instead of writing duplicate code to retrieve the .plist, convert the values to a dictionary, etc, each time I need the info, I thought a model class to hold the data and supply information would be appropriate. The application isn't very large, but it does handle a good deal of data. I'm not as skilled in writing model classes that conform to the MVC paradigm, and I'm looking for some strategies for this implementation that also supports lazy loading.. This model class should serve to supply data to any view controller that needs it and perform operations on the data (such as adding entries to dictionaries) when requested by the controller functions currently planned: returning the count on any dictionary adding one or more dictionaries together Currently, I have this method for supporting the count lookup for any dictionary. Would this be an example of lazy loading? -(NSInteger)countForDictionary: (NSString *)nameOfDictionary { NSBundle *bundle = [NSBundle mainBundle]; NSString *plistPath = [bundle pathForResource: nameOfDictionary ofType: @"plist"]; //load plist into dictionary NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] initWithContentsOfFile: plistPath]; NSInteger count = [dictionary count] [dictionary release]; [return count] }

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  • SQLAlchemy sessions - DetachedInstanceError?

    - by benjaminhkaiser
    I have a function that attempts to take a list of usernames, look each one up in a user table, and then add them to a membership table. If even one username is invalid, I want the entire list to be rolled back, including any users that have already been processed. I thought that using sessions was the best way to do this but I'm running into a DetachedInstanceError: DetachedInstanceError: Instance <Organization at 0x7fc35cb5df90> is not bound to a Session; attribute refresh operation cannot proceed Full stack trace is here. The error seems to trigger when I attempt to access the user (model) object that is returned by the query. From my reading I understand that it has something to do with there being multiple sessions, but none of the suggestions I saw on other threads worked for me. Code is below: def add_members_in_bulk(organization_eid, users): """Add users to an organization in bulk - helper function for add_member()""" """Returns "success" on success and id of first failed student on failure""" session = query_session.get_session() session.begin_nested() users = users.split('\n') for u in users: try: user = user_lookup.by_student_id(u) except ObjectNotFoundError: session.rollback() return u if user: membership.add_user_to_organization( user.entity_id, organization_eid, '', [] ) session.flush() session.commit() return 'success' here's the membership.add_user_to_organization: def add_user_to_organization(user_eid, organization_eid, title, tag_ids): """Add a User to an Organization with the given title""" user = user_lookup.by_eid(user_eid) organization = organization_lookup.by_eid(organization_eid) new_membership = OrganizationMembership( organization_eid=organization.entity_id, user_eid=user.entity_id, title=title) new_membership.tags = [get_tag_by_id(tag_id) for tag_id in tag_ids] crud.add(new_membership) and here is the lookup by ID query: def by_student_id(student_id, include_disabled=False): """Get User by RIN""" try: return get_query_set(include_disabled).filter(User.student_id == student_id).one() except NoResultFound: raise ObjectNotFoundError("User with RIN %s does not exist." % student_id)

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  • Glassfish 3: How do I get and use a developers build so I can navigate a stack trace including Glas

    - by Thorbjørn Ravn Andersen
    I am migrating a JSF 1.1 application to JEE 6 Web profile, and doing it in steps. I am in the process of moving from JSP with JSF 1.1 to Facelets under JSF 1.2 using the jsf-facelets.jar for JSF 1.2, and received an "interesting" stack trace when trying to lookup a key in a Map using a "{Bean.foo.map.key}" where the stacktrace complained about "key" not being a valid integer. (After code introspection I am workarounding it using a number as the key). That bug is not what this question is about. In such a situation it is essential to be able to navigate the source of every line in the stack trace. In Eclipse I normally attach a source jar to every jar on the build path, but in this particular case the Glassfish server adapter creates a library automatically containing the jars. Also there is to my knowledge no debug build of Glassfish where sources are included in the bundle. Glassfish is a non-trivial Maven project, and a bit picky too. I am not very familiar with maven, but have managed to checkout the code from Subversion and build it for the 3.0 tag according to http://wiki.glassfish.java.net/Wiki.jsp?page=V3FullBuildInstructions#section-V3FullBuildInstructions-CheckoutTheWorkspace - it appears to be the code corresponding to the official released 3.0 version. After finishing the "mvn -U install" part, I have then tried to create Eclipse projects by first using "mvn -DdownloadSources=true eclipse:eclipse" and then import them in Eclipse JEE 3.5.2 and specifying the M2_REPO variable but many of the projects still have compilation errors, and I cannot locate any instructions from Oracle about how to do this. I'd appreciate some help in just getting a functional IDE workspace reflecting the 3.0 version of Glassfish. I have Eclipse 3.5.2, Netbeans 6.8 and 6.9 beta, and IntelliJ IDEA 9, and Linux/Windows/OS X do do it on.

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  • Lightweight HTTP application/server for static content

    - by PartlyCloudy
    Hi, I am in need of a scalable and performant HTTP application/server that will be used for static file serving/uploading. So I only need support for GET and PUT operations. However, there are a few extra features that I need: Custom authentication: I need to check credentials against a database for each request. Thus I must be able to integrate propietary database interaction. Support for signed access keys: The access to resources via PUT should be signed using a key like http://uri/?key=foo The key then contains information about the request like md5(user + path + secret) which allows me to block unwanted requests. The application/server should allow me to check for this. Performance: I'd like to avoid piping content as much as possible. Otherwise the whole application could be implemented in Perl/etc. in a few lines as CGI. Perlbal (in webserver mode) looks nice, however the single-threaded model does not fit with my database lookup and it does also not support query strings. Lighttp/Nginx/… have some modules for these tasks, however it is not feasible putting everything together without ending up writing own extensions/modules. So how would you solve this? Are there other leightweight webservers available for this? Should I implement an application inside of a webserver (i.e. CGI). How can I avoid/speed up piping content between the webserver and my application. Thanks in advance!

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  • one key multiple values from different sources c#

    - by user2964034
    I am trying to make a c# program that will compare two files for me, and tell me the differences of specific parts. I have been able to get the parts I need into variables while looping through, but I now want to add these to a key with 3 values per file, so a key with 6 values overall which I will then compare to eachother later on. But I can only add 3 values at a time using the loop I have, so I need to be able to add the last 3 values to the key without overwriting the first 3. example of data from file: [\Advanced\Rules\Correlation Rules\Suspect_portscan\]; CheckDescription =S Detect Port scans; Enabled =B 0; Priority =L 3; I have managed to get what I need into variables so I have: string SigName would be "Suspect_portscan" Int Enabled, Priority, Blocking as 0 3 and null respectivly. I then want to make a dictionary type thing, with a key which would be the SigName and the first 3 values as enabled, priority, blocking. Then when looping through the second file, I want to add the 2nd files settings for the enabled, priority, blocking for the same SigName (so to the key) in the last 3 value slots. I will then compare this against itself, like 'if signame(0) != signame(3)' so if file 1 enabled is not the same as file two enabled make a note and tell me. But the problem I have is not being able to get the data into a dictionary or lookup, I'm completely stumped. It seems like I should use a dictionary with a list for the values but I cant get it working on the second loop through. Thanks.

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  • figuring out which field to look for a value in with SQL and perl

    - by Micah
    I'm not too good with SQL and I know there's probably a much more efficient way to accomplish what I'm doing here, so any help would be much appreciated. Thanks in advance for your input! I'm writing a short program for the local school high school. At this school, juniors and seniors who have driver's licenses and cars can opt to drive to school rather than ride the bus. Each driver is assigned exactly one space, and their DLN is used as the primary key of the driver's table. Makes, models, and colors of cars are stored in a separate cars table, related to the drivers table by the License plate number field. My idea is to have a single search box on the main GUI of the program where the school secretary can type in who/what she's looking for and pull up a list of results. Thing is, she could be typing a license plate number, a car color, make, and model, someone driver's name, some student driver's DLN, or a space number. As the programmer, I don't know what exactly she's looking for, so a couple of options come to mind for me to build to be certain I check everywhere for a match: 1) preform a couple of SELECT * FROM [tablename] SQL statements, one per table and cram the results into arrays in my program, then search across the arrays one element at a time with regex, looking for a matched pattern similar to the search term, and if I find one, add the entire record that had a match in it to a results array to display on screen at the end of the search. 2) take whatever she's looking for into the program as a scaler and prepare multiple select statements around it, such as SELECT * FROM DRIVERS WHERE DLN = $Search_Variable SELECT * FROM DRIVERS WHERE First_Name = $Search_Variable SELECT * FROM CARS WHERE LICENSE = $Search_Variable and so on for each attribute of each table, sticking the results into a results array to show on screen when the search is done. Is there a cleaner way to go about this lookup without having to make her specify exactly what she's looking for? Possibly some kind of SQL statement I've never seen before?

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  • Java and Jasper

    - by bhargava
    Hey Guys, I have integrated Jasper Reports on my netbeans platform and i am able to generate reports using the following code. Map<String, Object> params = new HashMap<String, Object>(); Connection conn = DriverManager.getConnection("databaseUrl", "userid","password"); JasperReport jasperReport = JasperCompileManager.compileReport(reportSource); JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, params, conn); JasperExportManager.exportReportToHtmlFile(jasperPrint, reportDest); JasperViewer.viewReport(jasperPrint); This stuff works perfect. But not i am trying to integrate Jasper with GWT.I have my server as glass fish server. I am getting the Connection object using the followind code. public static Connection getConnection() { try { String JNDI = "JNDI name"; InitialContext initCtx = new InitialContext(); javax.sql.DataSource ds = (javax.sql.DataSource) initCtx.lookup(JNDI); Connection conn = (Connection) ds.getConnection(); return conn; } catch (Exception ex) { ex.printStackTrace(); } return null; } and then Map params = new HashMap(); JasperReport jasperReport = JasperCompileManager.compileReport(reportSource); JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, params, getConnection()); JasperExportManager.exportReportToHtmlFile(jasperPrint, reportDest); JasperViewer.viewReport(jasperPrint); but i always get Error.I am implementing this on Server.I am having RPC calls to get this method to work when a button is clicked. Can you please help me how to work on this.(That is to integrate Jasper reports with GWT). I would highly appreciate any explanation with some code as i am just a beginner. Thanks

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  • Why can't I open a JBoss vfs:/ URL?

    - by skiphoppy
    We are upgrading our application from JBoss 4 to JBoss 6. A couple of pieces of our application get delivered to the client in an unusual way: jars are looked up inside of our application and sent to the client from a servlet, where the client extracts them in order to run certain support functions. In JBoss 4 we would look these jars up with the classloader and find a jar:// URL which would be used to read the jar and send its contents to the client. In JBoss 6 when we perform the lookup we get a vfs:/ URL. I understand that this is from the org.jboss.vfs package. Unfortunately when I call openStream() on this URL and read from the stream, I immediately get an EOF (read() returns -1). What gives? Why can't I read the resource this URL refers to? I've tried trying to access the underlying VFS packages to open the file through the JBoss VFS API, but most of the API appears to be private, and I couldn't find a routine to translate from a vfs:/ URL to a VFS VirtualFile object, so I couldn't get anywhere. I can try to find the file on disk within JBoss, but that approach sounds very failure prone on upgrade. Our old approach was to use Java Web Start to distribute the jars to the client and then look them up within Java Web Start's cache to extract them. But that broke on every minor upgrade of Java because the layout of the cache changed.

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  • Quick questions re moving to InfoPath forms

    - by sweissman
    Hi there: I’ve been asked to look into how best to move forms into InfoPath and have a couple of basic questions about your experiences so I can get an insider’s lay of the land. Even some short, quick bullets would be really helpful -- thank you! Are you starting from scratch in InfoPath, or are you converting from paper or a different e-format? (Jetform, PDF, etc.) Are you trying to re-create the layout of a specific paper form, or is a regular online form OK? (trying to learn what the latest thinking is about this) Do you need only simple fill and submit capabilities, or do you need programming for calculations, validation, database lookup/entry/reporting, etc. as well? (don’t know how much harder it is to do all this vs. not) How long does each form take to finish? (I know it depends, but is there a rough guideline for planning purposes?) Who’s doing the actual work? (by title or function) What is especially straightforward or challenging about moving to InfoPath forms? (forewarned is forearmed!)

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  • Schema for storing "binary" values, such as Male/Female, in a database

    - by latentflip
    Intro I am trying to decide how best to set up my database schema for a (Rails) model. I have a model related to money which indicates whether the value is an income (positive cash value) or an expense (negative cash value). I would like separate column(s) to indicate whether it is an income or an expense, rather than relying on whether the value stored is positive or negative. Question: How would you store these values, and why? Have a single column, say Income, and store 1 if it's an income, 0 if it's an expense, null if not known. Have two columns, Income and Expense, setting their values to 1 or 0 as appropriate. Something else? I figure the question is similar to storing a person's gender in a database (ignoring aliens/transgender/etc) hence my title. My thoughts so far Lookup might be easier with a single column, but there is a risk of mistaking 0 (false, expense) for null (unknown). Having seperate columns might be more difficult to maintain (what happens if we end up with a 1 in both columns? Maybe it's not that big a deal which way I go, but it would be great to have any concerns/thoughts raised before I get too far down the line and have to change my code-base because I missed something that should have been obvious! Thanks, Philip

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  • Dictionaries with more than one key per value in Python

    - by nickname
    I am attempting to create a nice interface to access a data set where each value has several possible keys. For example, suppose that I have both a number and a name for each value in the data set. I want to be able to access each value using either the number OR the name. I have considered several possible implementations: Using two separate dictionaries, one for the data values organized by number, and one for the data values organized by name. Simply assigning two keys to the same value in a dictionary. Creating dictionaries mapping each name to the corresponding number, and vice versa Attempting to create a hash function that maps each name to a number, etc. (related to the above) Creating an object to encapsulate all three pieces of data, then using one key to map dictionary keys to the objects and simply searching the dictionary to map the other key to the object. None of these seem ideal. The first seems ugly and unmaintainable. The second also seems fragile. The third/fourth seem plausible, but seem to require either much manual specification or an overly complex implementation. Finally, the fifth loses constant-time performance for one of the lookups. In C/C++, I believe that I would use pointers to reference the same piece of data from different keys. I know that the problem is rather similar to a database lookup problem by a non-key column, however, I would like (if possible), to maintain the approximate O(1) performance of Python dictionaries. What is the most Pythonic way to achieve this data structure?

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  • design pattern for related inputs

    - by curiousMo
    My question is a design question : let's say i have a data entry web page with 4 drop down lists, each depending on the previous one, and a bunch of text boxes. ddlCountry (DropDownList) ddlState (DropDownList) ddlCity (DropDownList) ddlBoro (DropDownList) txtAddress (TxtBox) txtZipcode(TxtBox) and an object that represents a datarow with a value for each: countrySeqid stateSeqid citySeqid boroSeqid address zipCode naturally the country, state, city and boro values will be values of primary keys of some lookup tables. when the user chooses to edits that record, i would load it from database and load it into the page. the issue that I have is how to streamline loading the DropDownLists. i have some code that would grab the object,look thru its values and move them to their corresponding input controls in one shot. but in this case i will have to load the ddlCountry with possible values, then assign values, then do the same thing for the rest of the ddls. I guess i am looking for an elegant solution. i am using asp.net, but i think it is irrelevant to the question. i am looking more into a design pattern.

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  • RPC command to initiate a software install

    - by ericmayo
    I was recently working with a product from Symantech called Norton EndPoint protection. It consists of a server console application and a deployment application and I would like to incorporate their deployment method into a future version of one of my products. The deployment application allows you to select computer workstations running Win2K, WinXP, or Win7. The selection of workstations is provided from either AD (Active Directory) or NT Domain (WINs/DNS NetBIOS lookup). From the list, one can click and choose which workstations to deploy the end point software which is Symantech's virus & spyware protection suite. Then, after selecting which workstations should receive the package, the software copies the setup.exe program to each workstation (presumable over the administrative share \pcname\c$) and then commands the workstation to execute setup.exe resulting in the workstation installing the software. I really like how their product works but not sure what they are doing to accomplish all the steps. I've not done any deep investigations into this such as sniffing the network, etc... and wanted to check here to see if anyone is familiar with what I'm talking about and if you know how it's accomplished or have ideas how it could be accomplished. My thinking is that they are using the admin share to copy the software to the selected workstations and then issuing an RPC call to command the workstation to do the install. What's interesting is that the workstations do this without any of the logged in users knowing what's going on until the very end where a reboot is necessary. At which point, the user gets a pop-up asking to reboot now or later, etc... My hunch is that the setup.exe program is popping this message. To the point: I'm looking to find out the mechanism by which one Windows based machine can tell another to do some action or run some program. My programming language is C/C++ Any thoughts/suggestions appreciated.

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  • Domain Authentication from .NET Client over VPN

    - by Holy Christ
    I am writing a ClickOnce WPF app that will sometimes be used over VPN. The app uses resources available only to domain authenticated users. Some of the things include accessing SSRS Reports, accessing LDAP to lookup user information, hitting web services, etc. When a user logs in from a machine that is not authenticated on the domain, I need to somehow get his credentials, authenticate him on the domain, and store his credentials. What is the recommended approach for authenticating domain users over VPN? How can I securely store the credentials? I've found several articles but, not much posted recently and a lot of the solutions seem kinda hacky, or aren't very secure (ie - storing strings clear text in memory). It would be cool if I could use the ActiveDicrtoryMembershipProvider, but that seems to be geared for use in web apps. EDIT: The above is kind of a workaround. The user must enter their domain credentials to authenticate on the VPN. It would be ideal to access the credentials the user has already entered to login to the VPN instead of the WindowsIdentity.GetCurrent() (which returns the user logged into the computer). Any ideas on how that could work? We use Juniper Networks to connect to the VPN. Thanks!

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  • Why would the same web form control render different "onclick" logic based on the page structure?

    - by zk812
    It was hard to title this question. :) I have a user control that is used to display a list of lookup items in my database and a delete button for each item (Editor User Control below). The delete button has an onClientClick event used to display a confirmation dialog in JavaScript. On page one, the confirmation pops up and functions correctly. The overall structure is: Master Page Page Editor User Control List of items with delete button On page two, the confirmation pops up but regardless of the answer, the page posts back anyway. The structure of this page is: Master Page Page User Control Editor User Control List of items with delete button For some reason, this makes a difference in how the delete button is rendered. Page one: <input type="image" name="ctl00...RequestTypesDataList$ctl01$ctl01" src="Images/Disable.png" alt="Delete" onclick="return ProcessDeleteCommand(1);" /> Page two: <input type="image" name="ctl00...RequestTypesDataList$ctl07$ctl01" src="Images/Disable.png" alt="Delete" onclick="return ProcessDeleteCommand(2);WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions(&quot;ctl00$ContentPlaceHolder1$RequestCreator1$RequestTypeEditor1$RequestTypesDataList$ctl07$ctl01&quot;, &quot;&quot;, true, &quot;&quot;, &quot;&quot;, false, false))" /> Does anyone know why page two renders WebForm_DoPostBackWithOptions after my JS check? It's causing the postback regardless of the confirmation choice.

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  • Geohashing - recursively find neighbors of neighbors

    - by itsme
    I am now looking for an elegant algorithm to recursively find neighbors of neighbors with the geohashing algorithm (http://www.geohash.org). Basically take a central geohash, and then get the first 'ring' of same-size hashes around it (8 elements), then, in the next step, get the next ring around the first etc. etc. Have you heard of an elegant way to do so? Brute force could be to take each neighbor and get their neighbors simply ignoring the massive overlap. Neighbors around one central geohash has been solved many times (here e.g. in Ruby: http://github.com/masuidrive/pr_geohash/blob/master/lib/pr_geohash.rb) Edit for clarification: Current solution, with passing in a center key and a direction, like this (with corresponding lookup-tables): def adjacent(geohash, dir) base, lastChr = geohash[0..-2], geohash[-1,1] type = (geohash.length % 2)==1 ? :odd : :even if BORDERS[dir][type].include?(lastChr) base = adjacent(base, dir) end base + BASE32[NEIGHBORS[dir][type].index(lastChr),1] end (extract from Yuichiro MASUI's lib) I say this approach will get ugly soon, because directions gets ugly once we are in ring two or three. The algorithm would ideally simply take two parameters, the center area and the distance from 0 being the center geohash only (["u0m"] and 1 being the first ring made of 8 geohashes of the same size around it (= [["u0t", "u0w"], ["u0q", "u0n"], ["u0j", "u0h"], ["u0k", "u0s"]]). two being the second ring with 16 areas around the first ring etc. Do you see any way to deduce the 'rings' from the bits in an elegant way?

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  • MVC design for archived data view

    - by Hemant Tank
    Implementation of a standard archive process in ASP.Net MVC. Backend SQL Server 2005 We've an existing web app built in MVC. We've an Entity "Claim" and it has some child entities like ClaimDetails, Files, etc... A pretty standard setup in DB. Each entity has its own table and are linked via FK. Now, we need to have an "Archive" feature in web app which will allow admin to archive a Claim and its child entities. An archived Claim shud become readonly when visited again. Here're some points on which I need your valued opinion - To keep it simple and scalable (for a few million records) for now we plan to simply add a bit field "Archived" to the Claim table in db. And change the behavior accordingly in the web app. We've a 'Manage claim' page which renders a bunch of diff views for Claim and its child entities. Now, for a readonly view we can either use the same views or have a separate set of views. What do you suggest? At controller level, we can identify archived claim and select which view to render. At model level, though it'd be great to be able to use the same model used for Manage Claim - but it might not get us the "text" of some lookup fields. For example, Claim.BrandId is rendered as a dropdown in Manage claim (requires only BrandId) but for readonly view we need 'BrandText'. Any existing ref or architecture level example would be great. Here's my prev SO post but its more about db level changes: Design a process to archive data (SQL Server 2005) Thank you.

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  • Computation overhead in C# - Using getters/setters vs. modifying arrays directly and casting speeds

    - by Jeffrey Kern
    I was going to write a long-winded post, but I'll boil it down here: I'm trying to emulate the graphical old-school style of the NES via XNA. However, my FPS is SLOW, trying to modify 65K pixels per frame. If I just loop through all 65K pixels and set them to some arbitrary color, I get 64FPS. The code I made to look-up what colors should be placed where, I get 1FPS. I think it is because of my object-orented code. Right now, I have things divided into about six classes, with getters/setters. I'm guessing that I'm at least calling 360K getters per frame, which I think is a lot of overhead. Each class contains either/and-or 1D or 2D arrays containing custom enumerations, int, Color, or Vector2D, bytes. What if I combined all of the classes into just one, and accessed the contents of each array directly? The code would look a mess, and ditch the concepts of object-oriented coding, but the speed might be much faster. I'm also not concerned about access violations, as any attempts to get/set the data in the arrays will done in blocks. E.g., all writing to arrays will take place before any data is accessed from them. As for casting, I stated that I'm using custom enumerations, int, Color, and Vector2D, bytes. Which data types are fastest to use and access in the .net Framework, XNA, XBox, C#? I think that constant casting might be a cause of slowdown here. Also, instead of using math to figure out which indexes data should be placed in, I've used precomputed lookup tables so I don't have to use constant multiplication, addition, subtraction, division per frame. :)

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  • Javascript, IE, Strings, and Performance problems

    - by Infinity
    Hey guys, So we have this product, and it's really slow in IE. We've already applied a lot of the practices advised by the IE guys themselves (like this, and this), and try to sacrifice clean code for performance in the critical parts like DOM manipulation. However, as you can see in this IE profiler screenshot.. Just "String" is the biggest offender. Almost 750ms of exclusive time. Does this mean IE is spending 750ms just instantiating Strings? I also read this stuff on the Opera dev blog: A build script can remove whitespace, comments, replace strings with Array lookups (to avoid MSIE creating a string object for every single instance of a string — even in conditions) But no more info regarding this. Anyone can clarify? It seems like IE has to create a full String instance every time you have " " in your code, which could explain this, but I don't know what the array lookup optimization would look like. BTW- we don't really do much of string concatenation anywhere in the code. The library we use is MooTools 1.2.4 Any suggestions will be appreciated! Thx

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  • Rails: RESTful Find, Initialize, or Create

    - by Andrew
    I have an app that has Cities in it. I'm looking for some suggestions on how to RESTfully structure a controller so that I can lookup, initialize, and create city records via AJAX requests. For instance: Given a text field city_name A user enters the name of a City, like "Paris, France" The app checks this location to see if there is such a city in the database already If there is, it returns the city object If there is not, it returns a new record initialized with the name "Paris" and the country "France", and prompts the user to confirm they want to add this city to the database If the user says "Yes" the record is saved. If not the record is discarded and the form is cleared. Now, my first approach was to change the Create action to use find_or_create, so that an AJAX post to cities_path would result in either returning the existing city or creating it and returning it. That works ok... However, it would be better to setup controller actions that would take a string input, find , or else initialize and return, then only create if the user confirms the generated record is correct. The ideal scenario would put this all in one action so AJAX request can go to that url, the server responds with JSON objects, and javascript can handle things from there. I'd like to keep all the user-interaction logic client side, and also minimize the number of requests it takes to achieve this. Any suggestions on the cleanest, most RESTful way to accomplish this?

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  • Shaping EF LINQ Query Results Using Multi-Table Includes

    - by sisdog
    I have a simple LINQ EF query below using the method syntax. I'm using my Include statement to join four tables: Event and Doc are the two main tables, EventDoc is a many-to-many link table, and DocUsage is a lookup table. My challenge is that I'd like to shape my results by only selecting specific columns from each of the four tables. But, the compiler is giving a compiler is giving me the following error: 'System.Data.Objects.DataClasses.EntityCollection does not contain a definition for "Doc' and no extension method 'Doc' accepting a first argument of type 'System.Data.Objects.DataClasses.EntityCollection' could be found. I'm sure this is something easy but I'm not figuring it out. I haven't been able to find an example of someone using the multi-table include but also shaping the projection. Thx,Mark var qry= context.Event .Include("EventDoc.Doc.DocUsage") .Select(n => new { n.EventDate, n.EventDoc.Doc.Filename, //<=COMPILER ERROR HERE n.EventDoc.Doc.DocUsage.Usage }) .ToList(); EventDoc ed; Doc d = ed.Doc; //<=NO COMPILER ERROR SO I KNOW MY MODEL'S CORRECT DocUsage du = d.DocUsage;

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