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  • Best and easiest algorithm to search for a vertex on a Graph?

    - by Nazgulled
    Hi, After implementing most of the common and needed functions for my Graph implementation, I realized that a couple of functions (remove vertex, search vertex and get vertex) don't have the "best" implementation. I'm using adjacency lists with linked lists for my Graph implementation and I was searching one vertex after the other until it finds the one I want. Like I said, I realized I was not using the "best" implementation. I can have 10000 vertices and need to search for the last one, but that vertex could have a link to the first one, which would speed up things considerably. But that's just an hypothetical case, it may or may not happen. So, what algorithm do you recommend for search lookup? Our teachers talked about Breadth-first and Depth-first mostly (and Dikjstra' algorithm, but that's a completely different subject). Between those two, which one do you recommend? It would be perfect if I could implement both but I don't have time for that, I need to pick up one and implement it has the first phase deadline is approaching... My guess, is to go with Depth-first, seems easier to implement and looking at the way they work, it seems a best bet. But that really depends on the input. But what do you guys suggest?

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  • DNS-Based Environment Determination

    - by zvolkov
    Found the following here. The questions is: where can I find more details on how exactly implement this on Windows? Any guide or how-to anybody? Or maybe you can provide your invaluable suggestions? Specifically, how do I make so that "all QA servers would first resolve entries in qa.example.com first and then if that lookup failed they would try example.com" (I'm a dev, not a DNS specialist, but our IT Support has refused to help on this:() Use DNS Based Environment Determination for your servers. Do this by initially splitting your top level domain into a number of sub domains depending on their function, and then creating DNS Service Names in each of the sub domains pointing to the relevant server for that service. Based on the list above we would then have: * clientdb.prod.example.com for Production * clientdb.perf.example.com for Performance Testing * clientdb.qa.example.com for QA * clientdb.dev.example.com for Development Servers then resolve entries in their relevant sub domain by function. That is, all QA servers would first resolve entries in qa.example.com first and then if that lookup failed they would try example.com. This allows you to have a single configuration entry for your client database hostname (clientdb) that would resolve correctly in all environments. This technique has the added advantage of still having global services defined in a common top level domain. Here's one related (but not equivalent) SO question: http://stackoverflow.com/questions/774490/dns-resolving-based-on-client-ip This seems to be related to Providing "split horizon" DNS service. Reading that, I see that I will probably need separate DNS Server for each environment. Is this true or does Windows support some form of "tagging" the records to be visible depending on the requestor's IP? Also, cross-posted on ServerFault

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  • Pros/Cons of MySQL vs Postgresql for production Ruby on Rails environment?

    - by cakeforcerberus
    I will soon be switching from sqlite3 to either postgres or mysql. What should I consider when making this decision? Is mysql more suited for Rails than postgres in some areas and/or vice versa? Or, as I somewhat suspect, does it not really matter either way? Another factor that might play into my decision is the availability of tools to data pump my test data from the sqlite3 db to my new one. Is there anything that ActiveRecord provides natively to do this or any decent plugins/gems to help with this task? BONUS: How do I pronounce "Postgresql" and sound like I know what I'm talking about? :) Thanks Greg Smith for providing the following link that shows the most common pronunciations: http://www.postgresql.org/community/survey.33 UPDATE: Reference this question for more: http://stackoverflow.com/questions/110927/do-you-recommend-postgresql-over-mysql FYI: I ended up using MySQL. There is a neat plugin called yamldb that really saved me some time with the data transfer from my sqlite db to my new mysql one. Instructions on how to install and use it can be found here: http://accidentaltechnologist.com/ruby/change-databases-in-rails-with-yamldb/ Thanks Tom

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  • How do you deal with denormalization / secondary indexes in database sharding?

    - by Continuation
    Say I have a "message" table with 2 secondary indexes: "recipient_id" "sender_id" I want to shard the "message" table by "recipient_id". That way to retrieve all messages sent to a certain recipient I only need to query one shard. But at the same time, I want to be able to make a query that ask for all messages sent by a certain sender. Now I don't want to send that query to every single shard of the "message" table. One way to do this is to duplicate the data and have a "message_by_sender" table sharded by "sender_id". The problem with that approach is that every time a message has been sent, I need to insert the message into both "message" and "message_by_sender" tables. But what if after inserting into "message" the insertion into "message_by_sender" fail? In that case the message exists in "message" but not in "message_by_sender". How do I make sure that if a message exists in "message" then it also exists in "message_by_sender" without resorting to 2 phase commit? This must be a very common issue for anyone who shards their databases. How do you deal woth it?

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  • VB.NET, templates, reflection, inheritance, feeling adrift

    - by brovar
    I've just made myself up a problem and am now wondering how to solve it. To begin with, I'm using some third-party components, including some calendar controls like schedule and timeline. They're used in the project classes more or less like that: Friend Class TimeBasedDataView 'some members End Class Friend Class ScheduleDataView Inherits TimeBasedDataView Public Schedule As Controls.Schedule.Schedule 'and others End Class Friend Class TimeLineDataView Inherits TimeBasedDataView Public TimeLine As Controls.TimeLine.TimeLine 'and others End Class (Hmm, code coloring fail, never mind...) Now, to allow managing the look of data being presented there are some mechanisms including so called Style Managers. A lot of code in them repeats, varying almost only with the control it maintains: Friend Class TimeLineStyleManager Private m_TimeLine As TimeLineDataView Private Sub Whatever() m_TimeLine.TimeLine.SomeProperty = SomeValue End Sub End Class Friend Class ScheduleStyleManager Private m_Schedule As ScheduleDataView Private Sub Whatever() m_Schedule.Schedule.SomeProperty = SomeValue End Sub End Class I was wondering if I could create some base class for those managers, like Friend Class TimeBasedCtrlStyleManagerBase(Of T As TimeBasedDataView) Private m_Control As T 'and others End Class which would unify these two, but I've got lost when it came to maintaining two components that have nothing in common (except their properties' names, etc.). Type reflection maybe? I'll be grateful for any advice ;)

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  • What do these errors mean? ISOC++ forbids assignment of arrays...

    - by xunlinkx
    I'm trying to compile some code on one of our systems for our DBA...I've edited the makefiles to include the pertinent libraries listed in the documentation, but I keep getting these errors... Can you discern any obvious problems from my command lines in reference to the errors listed? Thank you! make -f /u01/app/banner/ban8/TEST3/links/Makefile_tm_linux64_redhat5_ban8.mk gcc -m64 -D_NOFIXARGPTR -fpic -shared -DTMCILIB_EXPORTS -D_TMUNICODE -I/usr/local/ban_icu -I/usr/local/src/icu/source/i18n/ -I/usr/local/src/icu/source/common/ -I/usr/local/src/icu/source/extra/ustdio/ -I/usr/local/src/icu/source/io -L/usr/lib64 -L/usr/lib -L/usr/local/src/icu/source/data/ -L/usr/local/src/icu/source/data/out/ -L/usr/local/src/icu/source/tools/toolutil/ -L/usr/lib/im/icuconv/ -L/usr/local/lib/ -L. -licui18n -licudata -licuuc -licu-toolutil -licuio msgfmttm.cpp umsgtm.cpp tmcilib.cpp -o /u01/app/banner/ban8/TEST3/general/exe/libtmciuc.so umsgtm.cpp: In function ‘void fixArgPtr(const UChar*, __va_list_tag (*)[1])’: umsgtm.cpp:158: error: array must be initialized with a brace-enclosed initializer umsgtm.cpp:194: error: ISO C++ forbids assignment of arrays umsgtm.cpp: In function ‘int32_t tmumsg_vformat(void*, UChar, int32_t, __va_list_tag*, UErrorCode*)’: umsgtm.cpp:305: error: cannot convert ‘__va_list_tag**’ to ‘__va_list_tag ()[1]’ for argument ‘2’ to ‘void fixArgPtr(const UChar, __va_list_tag (*)[1])’ tmcilib.cpp: In function ‘int tmprintf(TMBundle*, const UChar*, ...)’: tmcilib.cpp:743: error: array must be initialized with a brace-enclosed initializer tmcilib.cpp: In function ‘int tmfprintf(TMBundle*, UFILE*, const UChar*, ...)’: tmcilib.cpp:757: error: array must be initialized with a brace-enclosed initializer tmcilib.cpp: In function ‘int tmsprintf(TMBundle*, UChar*, const UChar*, ...)’: tmcilib.cpp:808: error: array must be initialized with a brace-enclosed initializer

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  • Interactive Web Collaboration Platform

    - by user1477586
    I am currently unsatisfied with most, if not all, web-based collaboration tools I've ever used. Examples of what I'm considering a "web-based collaboration tool" are TWiki, WebEx, etc. What I have in mind of developing is to develop my own. The target "market" is for software/hardware developers who will likely be working on separate projects linked by a common goal. Example: You work at a company who is designing a brand new printer. So, one man is working on the ink cartridge, another on the paper feed, one on the circuitry of the printer and one more is working on the drivers. What I would like to make (unless it already exists) is a website that, upon loading, presents the user with a web that has each project within it's own bubble, graphically. These bubbles would all be linked to the central bubble of "[Company Name]". Upon selecting an individual bubble the browser would focus and zoom in on that project bubble and expand more information (in bullets or with more affiliated bubbles) about subprojects, progress, setbacks, etc. Then, at a terminal "node" (i.e. a bubble with no sub-bubbles) a selection would then load a page with information relevant to that node. That's a lot of monologue. In short, I want to know how I might approach this. My background is with algorithmic use of Python and C++. I've never done interactive web design like this; though, I have gone through the W3C tutorials on HTML4/5. I'm willing to learn a new language I'm just wondering which language/set of languages seem(s) most appropriate for this project. Thanks, world, for imparting your knowledge to me. An example of what the start page might look like is:

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  • Vertical-Align: A Full Explanation

    - by Livvy Jeffs
    I've been struggling with vertical alignments, a seemingly simple enough process that has a lot of idiosyncrasies throughout different languages and element types. I've done a lot of reading through stackexchange and can't seem to find a common thread of understanding. Here are the rules that I have been able to gather: 1) Vertical-align does not work in <\div>s, you have to set div {display: table-cell; vertical-align: middle} This seems like a big hassle, especially since table-cells override the height limitation even when overflow is set to hidden and expands to fit content, which means the vertical "center" is variable. I just read some source-code from Pinterest where button {vertical-align: middle}, but no other vertical-align commands seem to work. It seems as if button is by default aligned in the middle. Can someone provide a clear explanation for the vertical-align attribute? What html elements respond to vertical-align? Which html elements have default vertical-align attributes? Which html elements have non-overridable vertical-align attributes? And any clues as to understanding the idiosyncracies would help as well! Thanks in advance!

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  • How do I begin reading source code?

    - by anonnoir
    I understand the value of reading source code, and I am trying my best to read as much as I can. However, every time I try getting into a 'large' (i.e. complete) project of sorts, I am overwhelmed. For example, I use Anki a lot when revising languages. Also, I'm interested in getting to know how an audio player works (because I have some project ideas), hence quodlibet on Google Code. But whenever I open the source code folders for the above programs, there are just so many files that I don't know where or what to begin with. I think that I should start with files marked init.py but I can't see the logical structure of the programs, or what reasoning was applied when the original writer divided his modules the way he did. Hence, my questions: How/where should I begin reading source? Any general tips or ideas? How does a programmer keep in mind the overall structure and logic of the program, especially for large projects, and is it common not to document that structure? As an open source reader, must I look through all of the code and get a bird's eye view of the code and libraries, before even being able to proceed? Would an IDE like Eclipse SDK (with PyDev) help with code-reading? Thanks for the help; I really appreciate your helping me.

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  • Alternate cause of BadImageFormatException in .NET Assembly?

    - by Phillip Knauss
    I'm working on a .NET 3.5 console application in C# which uses a VC++ unmanaged DLL. It ran without a problem when I worked on it a few weeks ago, but I'm coming back to it today and am now getting a BadImageFormatException ("An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)). My development workstation is running 64bit Windows 7, and I do a fair amount of work with unmanaged code, so I immediately checked that the .NET assembly and the VC++ library both had x86 targets. They did. Just to be sure, I cleaned and rebuilt the VC++ library and the .NET assembly, to no avail. Neither system is doing anything particularly unusual. The VC++ library loads a binary data file and does some mathematical processing on its contents. The .NET assembly has the DllImports for the library and some code to wire it up. This all worked a few weeks ago. So now I'm left wondering if there's some other cause of BadImageFormatException that's less common than an x86/x64 conflict that I might be running into. Thanks.

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  • How can I test this SQL Server performance Utility?

    - by Martin Smith
    As part of my MSc I need to do a three month project later this year. I have decided to do something which will likely be useful for me in the workplace and spend the time getting to understand SQL Server internals. The deliverable for this project will be a performance advisor looking at a variety of different rules. Some static such as finding redundant indexes, some more dynamic such as using XEvents to find outlying invocations of stored procedure execution times when certain parameters are passed. I am struggling to come up with a good way of testing this though. I can obviously design a "bad" database and a synthetic workload that my tool will pick up issues on but I also need to demonstrate that it has real world utility. Looking at the self tuning database literature it is common to use TPC benchmarks but I've had a look at the TPCC site and it looks very time consuming to implement and not that good a fit to my project's testing needs in any event (I would still be able to "rig" it by the decisions I made on indexing or physical architecture). Plan A would be to find willing beta tester(s) but in the event that isn't possible I will need a fallback plan. The best idea I have come up with so far is to use the various MS sample applications as examples of real world applications. e.g. http://msftdpprodsamples.codeplex.com/ http://www.asp.net/community/projects/ Does anyone have any better suggestions?

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  • A simple WCF Service (POX) without complex serialization

    - by jammer59
    I'm a complete WCF novice. I'm trying to build a deploy a very, very simple IIS 7.0 hosted web service. For reasons outside of my control it must be WCF and not ASMX. It's a wrapper service for a pre-existing web application that simply does the following: 1) Receives a POST request with the request body XML-encapsulated form elements. Something like valuevalue. This is untyped XML and the XML is atomic (a form) and not a list of records/objects. 2) Add a couple of tags to the request XML and the invoke another HTTP-based service with a simple POST + bare XML -- this will actually be added by some internal SQL ops but that isn't the issue. 3) Receive the XML response from the 3rd party service and relay it as the response to the original calling client in Step 1. The clients (step 1) will be some sort of web-based scripting but could be anything .aspx, python, php, etc. I can't have SOAP and the usual WCF-based REST examples with their contracts and serialization have me confused. This seems like a very common and very simple problem conceptually. It would be easy to implement in code but IIS-hosted WCF is a requirement. Any pointers?

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  • Requested Service not found - .NET Remoting

    - by bharat
    I am Getting this exception System.Runtime.Remoting.RemotingException occurred Message="Object '/55337266_9751_4f58_8446_c54ff254222e/rkutlpt5hvsxipmzhb+jkqyl_98.rem' has been disconnected or does not exist at the server." Source="mscorlib" StackTrace: Server stack trace: at System.Runtime.Remoting.Channels.ChannelServices.CheckDisconnectedOrCreateWellKnownObject(IMessage msg) at System.Runtime.Remoting.Channels.ChannelServices.DispatchMessage(IServerChannelSinkStack sinkStack, IMessage msg, IMessage& replyMsg) Exception rethrown at [0]: at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) at Common.Interface.Repository.NA.INRR.GetNRun(Int32 NetworkRunId) at Module.NA.ViewModel.NRDViewModel.get_AS() InnerException: Most of the times i am getting this exception this is my remotingDomain method string tcpURL; TcpChannel channel; channel = new TcpChannel(); ChannelServices.RegisterChannel(channel, false); //-- // Remote domain objects //-- tcpURL = string.Format("tcp://{0}:{1}/DomainComposition", ServerName, TcpPort); RemotingConfiguration.RegisterWellKnownClientType(typeof(DomainComposition), tcpURL); //-- // Remote repository objects //-- tcpURL = string.Format("tcp://{0}:{1}/RepositoryComposition", ServerName, TcpPort); RemotingConfiguration.RegisterWellKnownClientType(typeof(RepositoryComposition), tcpURL); //-- // Remote utility objects //-- tcpURL = string.Format("tcp://{0}:{1}/UtilityComposition", ServerName, TcpPort); RemotingConfiguration.RegisterWellKnownClientType(typeof(UtilityComposition), tcpURL); this.Domain = new DomainComposition(); this.Repository = new RepositoryComposition(); this.Utility = new UtilityComposition(); How to Check if the object is disconnect then re initiate the service

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  • Firebird Data Access Designer (DDEX) installation

    - by persian Dev
    hi i want to use firebird library , and i followed its instruction as below , but i get "The referenced component 'FirebirdSql.Data.Firebird' could not be found." error. instruction : Prerequisites Make sure that you have Visual Studio .NET 2005 Standard or higher edition. Express editions are not supported. Registry update Remember to update the path in FirebirdDDEXProviderPackageLess32.reg or FirebirdDDEXProviderPackageLess64.reg, places where to update it are marked %Path%. Install the .reg file into the registry. Machine.config update Add the following two sections to machine.config (located usually at C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\CONFIG\machine.config and C:\WINDOWS\Microsoft.NET\Framework64\v2.0.50727\CONFIG\machine.config on 64-bit system). <configuration> ... <configSections> ... <section name="firebirdsql.data.firebirdclient" type="System.Data.Common.DbProviderConfigurationHandler, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" /> ... </configSections> ... <system.data> <DbProviderFactories> ... <add name="FirebirdClient Data Provider" invariant="FirebirdSql.Data.FirebirdClient" description=".Net Framework Data Provider for Firebird" type="FirebirdSql.Data.FirebirdClient.FirebirdClientFactory, FirebirdSql.Data.FirebirdClient, Version=%Version%, Culture=%Culture%, PublicKeyToken=%PublicKeyToken%" /> ... </DbProviderFactories> </system.data> ... </configuration> And subst: %Version% With the version of the provider assembly that you have in the GAC. %Culture% With the culture of the provider assembly that you have in the GAC. %PublicKeyToken% With the PublicKeyToken of the provider assembly that you have in the GAC.

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  • Assembly reference from ASP.NET App_Code directory

    - by Gerald Schneider
    I have trouble getting a custom ObjectDataSource for an asp:ListView control to work. I have the class for the DataSource in the App_Code directory of the web application (as required by the asp:ListView control). using System; using System.Collections.Generic; using System.ComponentModel; using System.Configuration; using System.Data; using System.Data.Common; using System.Web; using System.DirectoryServices; [DataObject] public class UsersDAL { [DataObjectMethod(DataObjectMethodType.Select)] public List<User> LoadAll(int startIndex, int maxRows, string sortedBy) { List<User> users = new List<User>(); DirectoryEntry entry; return users; } } As soon as I add using System.DirectoryServices; the page crashes with this message: Compiler Error Message: CS0234: The type or namespace name 'DirectoryServices' does not exist in the namespace 'System' (are you missing an assembly reference?) Without the usage of System.DirectoryServices the page loads without problems. The reference is there, it is working in classes outside the App_Code directory.

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  • Java: dangerous self-returning-recursive function by IOException?

    - by HH
    I had very errorsome Exception handling with if-clauses. An exception occurs if not found path. An exception returns the function again. The function is recursive. Safe? $ javac SubDirs.java $ java SubDirs Give me an path. . HELLO com TOASHEOU google common annotations base collect internal Give me an path. IT WON'T FIND ME, SO IT RETURNS ITSELF due to Exception caught Give me an path. $ cat SubDirs.java import java.io.*; import java.util.*; public class SubDirs { private List<File> getSubdirs(File file) throws IOException { List<File> subdirs = Arrays.asList(file.listFiles(new FileFilter() { public boolean accept(File f) { return f.isDirectory(); } })); subdirs = new ArrayList<File>(subdirs); List<File> deepSubdirs = new ArrayList<File>(); for(File subdir : subdirs) { deepSubdirs.addAll(getSubdirs(subdir)); } subdirs.addAll(deepSubdirs); return subdirs; } public static void search() { try{ BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); String s; System.out.println("Give me an path."); while ((s = in.readLine()) != null && s.length() != 0){ SubDirs dirs = new SubDirs(); List<File> subDirs = dirs.getSubdirs(new File(s)); for ( File f : subDirs ) { System.out.println(f.getName()); } System.out.println("Give me an path."); } }catch(Exception e){ // Simple but is it safe? search(); } } public static void main(String[] args) throws IOException { search(); } }

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  • F# passing an operator with arguments to a function

    - by dan
    Can you pass in an operation like "divide by 2" or "subtract 1" using just a partially applied operator, where "add 1" looks like this: List.map ((+) 1) [1..5];; //equals [2..6] // instead of having to write: List.map (fun x-> x+1) [1..5] What's happening is 1 is being applied to (+) as it's first argument, and the list item is being applied as the second argument. For addition and multiplication, this argument ordering doesn't matter. Suppose I want to subtract 1 from every element (this will probably be a common beginners mistake): List.map ((-) 1) [1..5];; //equals [0 .. -4], the opposite of what we wanted 1 is applied to the (-) as its first argument, so instead of (list_item - 1), I get (1 - list_item). I can rewrite it as adding negative one instead of subtracting positive one: List.map ((+) -1) [1..5];; List.map (fun x -> x-1) [1..5];; // this works too I'm looking for a more expressive way to write it, something like ((-) _ 1), where _ denotes a placeholder, like in the Arc language. This would cause 1 to be the second argument to -, so in List.map, it would evaluate to list_item - 1. So if you wanted to map divide by 2 to the list, you could write: List.map ((/) _ 2) [2;4;6] //not real syntax, but would equal [1;2;3] List.map (fun x -> x/2) [2;4;6] //real syntax equivalent of the above Can this be done or do I have to use (fun x -> x/2)? It seems that the closest we can get to the placeholder syntax is to use a lambda with a named argument.

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  • Create a dynamic project template in VS 2010?

    - by jonhobbs
    This might sound a bit of an odd question but I know what I want to achieve, just don't know if it's possible. Firstly, I'd like to be able to create a visual studio project that the 2 developers that work with me can use as a basis for all new websites. I want to drop all the common files that we use in there, like jQuery, CMS files etc. so that every time they start a new project they don't have to worry about all of that stuff. I guess to do this I just set up a project and "File Export Template" ? Now, here's the tricky bit... When you open up one of the default templates in VS it asks you a few questions, such as if you want to use a master page or if you want to use code behind etc. What I would like to do is set up something similar so that when you use the project template it asks you what version of jQuery you want to use so that it can import the right file, or for example it might ask you if you want to include certain user controls that the CMS contains. If you tick the box then the folder with the necessary user controls would be put in your new project for you. I know MS can do this but can a user like me include functionality like that in my own project template? Hope that makes sense.

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  • Worklight client-side API to overrideBackButton doesn't work

    - by user2503429
    I want to make something happen when back button is pressed so I put this code in Myhtml.js file : function wlCommonInit(){ /* * Application is started in offline mode as defined by a connectOnStartup property in initOptions.js file. * In order to begin communicating with Worklight Server you need to either: * * 1. Change connectOnStartup property in initOptions.js to true. * This will make Worklight framework automatically attempt to connect to Worklight Server as a part of application start-up. * Keep in mind - this may increase application start-up time. * * 2. Use WL.Client.connect() API once connectivity to a Worklight Server is required. * This API needs to be called only once, before any other WL.Client methods that communicate with the Worklight Server. * Don't forget to specify and implement onSuccess and onFailure callback functions for WL.Client.connect(), e.g: * * WL.Client.connect({ * onSuccess: onConnectSuccess, * onFailure: onConnectFailure * }); * */ // Common initialization code goes here } WL.App.overrideBackButton(backFunc); function backFunc(){ alert('You will back to previous page'); } but after build and deploy the app and I running it, nothing happened after I pressed back button, anybody have the solution ?

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  • Am I correctly extracting JPEG binary data from this mysqldump?

    - by Glenn
    I have a very old .sql backup of a vbulletin site that I ran around 8 years ago. I am trying to see the file attachments that are stored in the DB. The script below extracts them all and is verified to be JPEG by hex dumping and checking the SOI (start of image) and EOI (end of image) bytes (FFD8 and FFD9, respectively) according to the JPEG wiki page. But when I try to open them with evince, I get this message "Error interpreting JPEG image file (JPEG datastream contains no image)" What could be going on here? Some background info: sqldump is around 8 years old vbulletin 2.x was the software that stored the info most likely php 4 was used most likely mysql 4.0, possibly even 3.x the column datatype these attachments are stored in is mediumtext My Python 3.1 script: #!/usr/bin/env python3.1 import re trim_l = re.compile(b"""^INSERT INTO attachment VALUES\('\d+', '\d+', '\d+', '(.+)""") trim_r = re.compile(b"""(.+)', '\d+', '\d+'\);$""") extractor = re.compile(b"""^(.*(?:\.jpe?g|\.gif|\.bmp))', '(.+)$""") with open('attachments.sql', 'rb') as fh: for line in fh: data = trim_l.findall(line)[0] data = trim_r.findall(data)[0] data = extractor.findall(data) if data: name, data = data[0] try: filename = 'files/%s' % str(name, 'UTF-8') ah = open(filename, 'wb') ah.write(data) except UnicodeDecodeError: continue finally: ah.close() fh.close() update The JPEG wiki page says FF bytes are section markers, with the next byte indicating the section type. I see some that are not listed in the wiki page (specifically, I see a lot of 5C bytes, so FF5C). But the list is of "common markers" so I'm trying to find a more complete list. Any guidance here would also be appreciated.

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  • Add new types to Go

    - by nevalu
    I'm trying add new types for that been managed/used as in Go core types. To create new types is anything very interesting to validate data before of send it to a non-SQL DBMS or to check data from a form. Go uses univeral constants to define them at global level: var DateType = universe.DefineType("date", universePos, &dateType{}) In this case they're defined to be called from a package like types: var Date = &dateType{} I get these errors: test.go:58: o.lit undefined (cannot refer to unexported field lit) test.go:62: *dateType is not Type missing Pos() token.Position The code is based on: http://github.com/tav/go/blob/master/src/pkg/exp/eval/value.go http://github.com/tav/go/blob/master/src/pkg/exp/eval/type.go package main import ( "exp/eval" "fmt" // "go/token" ) // http://github.com/tav/go/blob/master/src/pkg/exp/eval/value.go type DateValue interface { eval.Value Get(*eval.Thread) string Set(*eval.Thread, string) } /* Date */ type dateV string func (v *dateV) String() string { return fmt.Sprint(*v) } func (v *dateV) Assign(t *eval.Thread, o eval.Value) { *v = dateV(o.(DateValue).Get(t)) } func (v *dateV) Get(*eval.Thread) string { return string(*v) } func (v *dateV) Set(t *eval.Thread, x string) { *v = dateV(x) } // http://github.com/tav/go/blob/master/src/pkg/exp/eval/type.go type Type interface { eval.Type // isDate returns true if this is a date type. isDate() bool } /* Common type */ type commonType struct{} // added func (commonType) isDate() bool { return false } /* Date */ type dateType struct { commonType } // * It should not be an universal constant //var universePos = token.Position{"<universe>", 0, 0, 0} // added //var DateType = universe.DefineType("date", universePos, &dateType{}) var Date = &dateType{} func (t *dateType) compat(o Type, conv bool) bool { t2, ok := o.lit().(*dateType) return ok && t == t2 } func (t *dateType) lit() Type { return t } func (t *dateType) isDate() bool { return true } func (t *dateType) String() string { return "<date>" } func (t *dateType) Zero() eval.Value { res := dateV("") return &res } /* Named types */ /* type NamedType struct { eval.NamedType Def Type }*/ type NamedType struct { // added // token.Position Name string // Underlying type. If incomplete is true, this will be nil. // If incomplete is false and this is still nil, then this is // a placeholder type representing an error. Def Type // True while this type is being defined. incomplete bool methods map[string]eval.Method } func (t *NamedType) isDate() bool { return t.Def.isDate() } /* *********************** */ func main() { print("foo") }

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  • shared memory STL maps

    - by user306963
    Hello, I am writing an Apache module in C++. I need to store the common data that all childs need to read as a portion of shared memory. Structure is kind of map of vectors, so I want to use STL map and vectors for it. I have written a shared allocator and a shared manager for the purpose, they work fine for vectors but not for maps, below is the example: typedef vector<CustomersData, SharedAllocator<CustomersData> > CustomerVector; CustomerVector spData; //this one works fine typedef SharedAllocator< pair< const int, CustomerVector > > PairAllocator; typedef map< int, CustomerVector, less<int>, PairAllocator > SharedMap; SharedMap spIndex; //this one doesn't work I get compile time errors when I try to use the second object (spIndex), which are someting like: ../SpatialIndex.h:97: error: '((SpatialIndex*)this)-SpatialIndex::spIndex' does not have class type It looks like the compiler cannot determine a type for SharedMap template type, which is strange in my opinion, it seems to me that all the template parameters have been specified. Can you help? Thanks Benvenuto

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  • How does a java web project architecture look like without EJB3 ?

    - by Hendrik
    A friend and I are building a fairly complex website based on java. (PHP would have been more obvious but we chose for java because the educational aspect of this project is important to us) We have already decided to use JSF (with richfaces) for the front end and JPA for the backend and so far we have decided not to use EJB3 for the business layer. The reason we've decided not to use EJB3 is because - and please correct me if I am wrong - if we use EJB3 we can only run it on a full blown java application server like jboss and if we don't use EJB3 we can still run it on a lightweight server like tomcat. We want to keep speed and cost of our future web server in mind. So far i've worked on two JEE projects and both used the full stack with web business logic factories/persistence service entities with every layer a seperate module. Now here is my question, if you dont use EJB3 in the business logic layer. What does the layer look like? Please tell what is common practice when developing java web projects without ejb3? Do you think business logic layer can be thrown out altogether and have business logic in the backing beans? If you keep the layer, do you have all business methods static? Or do you initialize each business class as needed in the backing beans in every session as needed?

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  • Is jQuery always the answer?

    - by Kibbee
    I've come across a couple questions, such as this one, and I really have to wonder why "Use jQuery" seems to be the answer when somebody asks how to do something in JavaScript. I understand that jQuery can save you a lot of time, and can help you out a lot, especially when you are doing a lot of fancy JavaScript in your site. However, in instances like this, and in many other instances, it seems like it's just jumping around the problem instead of answering the question. I also feel like this builds too much dependency into libraries. I've seen way too many developers that simply rely too much on libraries, and if they encounter a situation where they didn't have the library, they would be completely unable to function. I feel like there are already enough developers who don't know JavaScript, without just telling everybody to not learn JavaScript, and use jQuery. So, just to reiterate the question. Do you think there's too much of a tendency to use jQuery, for small pieces of JavaScript, when most of the functionality of jQuery isn't being used. Should developers be fluent in the use of bare JavaScript so they don't get too dependent on using libraries? [Additional related conversation topic] Does the existence of jQuery give too much slack to web browser developers who write the JavaScript engines? If we just have workarounds to cover all the inconsistencies in JavaScript, what pressure is there on browser makers to ensure that their JavaScript library works as it should. I feel like this extrapolates the same problem discussed in SO Podcast #36 of "be conservative in what you send, liberal in what you accept". By being so liberal with bad JavaScript engines, and using a common library to work around the flaws, we are promoting their use, and extending the problem.

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  • Linq-to-SQL produces bad SQL?

    - by strager
    I am trying to run a Linq-to-SQL query, but when the query is evaluated, I get the following exception: System.Data.OleDb.OleDbException was unhandled Message=The SELECT statement includes a reserved word or an argument name that is misspelled or missing, or the punctuation is incorrect. Source=Microsoft JET Database Engine ErrorCode=-2147217900 StackTrace: at System.Data.OleDb.OleDbCommand.ExecuteCommandTextErrorHandling(OleDbHResult hr) at System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARAMS dbParams, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) at System.Data.OleDb.OleDbCommand.ExecuteReader(CommandBehavior behavior) at System.Data.OleDb.OleDbCommand.ExecuteDbDataReader(CommandBehavior behavior) at System.Data.Common.DbCommand.ExecuteReader() at System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult) at System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries) at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) at System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression) at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source) at xxx.InventoryPopulator`2.Clear(String barcode) in F:\Projects\C#\xxx\xxx\InventoryPopulator.cs:line 38 [..etc..] InnerException: The debugger shows my query is: SELECT [t0].[SupplierID] AS [Id], [t0].[SupplierSKU] AS [Sku], [t0].[LocalSKU] AS [LocalSku], [t0].[ManufacturersBarcode] AS [Barcode], [t0].[QuantityAvailable] FROM [inventorySupplier] AS [t0] WHERE [t0].[ManufacturersBarcode] = @p0 And the Linq query which generates the above is: var items = from item in this.supplierItems where item.Barcode == barcode select item; How do I fix my query?

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