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• CI + Joomla 1.5

  - by DMin

  Hi, This is something that I just cooked up with Joomla and CodeIgniter(CI). I Wrote my database intensive application in CodeIgniter and frontend is Joomla. I'm using Jumi(Joomla Extention) so I can include the CI files inside joomla to basically insert the content generated by CI into Joomla articles. Problem is, you can't include CI files directly using JUMI from joomla because CI tends to route the pages so instead of seeing your joomla page with the CI content, you be redirected to the CI page itself. I did a little work around for this : Made an additional page that just basically does cURL to the CI page - gets the data and echos it out. From jumi, I include this cURL page instead. Couple of questions: I've seen at least a few posts that CI + Joomla is difficult to do(link). 1) Do you see any glaring security issues or possible performance issues? 2) Do you know of a better way to implement this? 3) What do you think of this? Do you think this is a good way to do this? There is one component out there that plugs CI with Joomla but it requires you to have a fresh CI install. It allows only one controller & the download link is down as well.

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• Is there a faster way to access a property member of a class using reflection?

  - by Ross Goddard

  I am currently using the following code to access the property of an object using reflection: Dim propInfo As Reflection.PropertyInfo = myType.GetProperty(propName) Dim objValue As Object = propInfo.GetValue(myObject, Nothing) I am having some issues with the speed since this type of code is being called many times and is causing some slowdown. I have been looking into using Refelction.Emit or dynamic methods, but I am not sure exactly how to make use of them. Background Information: I am creating a list of a subset of the properties of the object, associating then with some meta information (such as if they can be loaded from the database or xml, if they are editable, can the user see them). This is for later consumption so we can write code such as : foreach prop as BaseWrapper in graphNode.NodeProperties prop.LoadFromDataRow(dr) next The application makes heavy use of having access to this list. The problem is that on the initial load of a project, a larger number of objects are being created that make use of this, so for each object created it is looping through this code a number of times. I initially tried adding each property to the list manually, but this ran into problems with not everything being initialized at the correct time and some other issues. If there is no other good way, then I may have to rethink some of the design and see what else can be done to improve the performance.

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• Color banding only on Android 4.0+

  - by threeshinyapples

  On emulators running Android 4.0 or 4.0.3, I am seeing horrible colour banding which I can't seem to get rid of. On every other Android version I have tested, gradients look smooth. I have a SurfaceView which is configured as RGBX_8888, and the banding is not present in the rendered canvas. If I manually dither the image by overlaying a noise pattern at the end of rendering I can make the gradients smooth again, though obviously at a cost to performance which I'd rather avoid. So the banding is being introduced later. I can only assume that, on 4.0+, my SurfaceView is being quantized to a lower bit-depth at some point between it being drawn and being displayed, and I can see from a screen capture that gradients are stepping 8 values at a time in each channel, suggesting a quantization to 555 (not 565). I added the following to my Activity onCreate function, but it made no difference. getWindow().setFormat(PixelFormat.RGBA_8888); getWindow().addFlags(WindowManager.LayoutParams.FLAG_DITHER); I also tried putting the above in onAttachedToWindow() instead, but there was still no change. (I believe that RGBA_8888 is the default window format anyway for 2.2 and above, so it's little surprise that explicitly setting that format has no effect on 4.0+.) Which leaves the question, if the source is 8888 and the destination is 8888, what is introducing the quantization/banding and why does it only appear on 4.0+? Very puzzling. I wonder if anyone can shed some light?

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• Optimising ruby regexp -- lots of match groups

  - by Farcaller

  I'm working on a ruby baser lexer. To improve performance, I joined up all tokens' regexps into one big regexp with match group names. The resulting regexp looks like: /\A(?<__anonymous_-1038694222803470993>(?-mix:\n+))|\A(?<__anonymous_-1394418499721420065>(?-mix:\/\/[\A\n]*))|\A(?<__anonymous_3077187815313752157>(?-mix:include\s+"[\A"]+"))|\A(?<LET>(?-mix:let\s))|\A(?<IN>(?-mix:in\s))|\A(?<CLASS>(?-mix:class\s))|\A(?<DEF>(?-mix:def\s))|\A(?<DEFM>(?-mix:defm\s))|\A(?<MULTICLASS>(?-mix:multiclass\s))|\A(?<FUNCNAME>(?-mix:![a-zA-Z_][a-zA-Z0-9_]*))|\A(?<ID>(?-mix:[a-zA-Z_][a-zA-Z0-9_]*))|\A(?<STRING>(?-mix:"[\A"]*"))|\A(?<NUMBER>(?-mix:[0-9]+))/ I'm matching it to my string producing a MatchData where exactly one token is parsed: bigregex =~ "\n ... garbage" puts $~.inspect Which outputs #<MatchData "\n" __anonymous_-1038694222803470993:"\n" __anonymous_-1394418499721420065:nil __anonymous_3077187815313752157:nil LET:nil IN:nil CLASS:nil DEF:nil DEFM:nil MULTICLASS:nil FUNCNAME:nil ID:nil STRING:nil NUMBER:nil> So, the regex actually matched the "\n" part. Now, I need to figure the match group where it belongs (it's clearly visible from #inspect output that it's _anonymous-1038694222803470993, but I need to get it programmatically). I could not find any option other than iterating over #names: m.names.each do |n| if m[n] type = n.to_sym resolved_type = (n.start_with?('__anonymous_') ? nil : type) val = m[n] break end end which verifies that the match group did have a match. The problem here is that it's slow (I spend about 10% of time in the loop; also 8% grabbing the @input[@pos..-1] to make sure that \A works as expected to match start of string (I do not discard input, just shift the @pos in it). You can check the full code at GH repo. Any ideas on how to make it at least a bit faster? Is there any option to figure the "successful" match group easier?

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• Detecting well behaved / well known bots

  - by Simon_Weaver

  I found this question very interesting : Programmatic Bot Detection I have a very similar question, but I'm not bothered about 'badly behaved bots'. I am tracking (in addition to google analytics) the following per visit : Entry URL Referer UserAgent Adwords (by means of query string) Whether or not the user made a purchase etc. The problem is that to calculate any kind of conversion rate I'm ending up with lots of 'bot' visits that are greatly skewing my results. I'd like to ignore as many as possible bot visits, but I want a solution that I don't need to monitor too closely, and that won't in itself be a performance hog and preferably still work if someone has javascript disabled. Are there good published lists of the top 100 bots or so? I did find a list at http://www.user-agents.org/ but that appears to contain hundreds if not thousands of bots. I don't want to check every referer against thousands of links. Here is the current googlebot UserAgent. How often does it change? Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)

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• Database solution for 200million writes/day, monthly summarization queries

  - by sb

  Hello. I'm looking for help deciding on which database system to use. (I've been googling and reading for the past few hours; it now seems worthwhile to ask for help from someone with firsthand knowledge.) I need to log around 200 million rows (or more) per 8 hour workday to a database, then perform weekly/monthly/yearly summary queries on that data. The summary queries would be for collecting data for things like billing statements, eg. "How many transactions of type A did each user run this month?" (could be more complex, but that's the general idea). I can spread the database amongst several machines, as necessary, but I don't think I can take old data offline. I'll definitely need to be able to query a month's worth of data, maybe a year. These queries would be for my own use, and wouldn't need to be generated in real-time for an end-user (they could run overnight, if needed). Does anyone have any suggestions as to which databases would be a good fit? P.S. Cassandra looks like it would have no problem handling the writes, but what about the huge monthly table scans? Is anyone familiar with Cassandra/Hadoop MapReduce performance?

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• Aliasing `T*` with `char*` is allowed. Is it also allowed the other way around?

  - by StackedCrooked

  Note: This question has been renamed and reduced to make it more focused and readable. Most of the comments refer to the old text. According to the standard objects of different type may not share the same memory location. So this would not be legal: int i = 0; short * s = reinterpret_cast<short*>(&i); // BAD! The standard however allows an exception to this rule: any object may be accessed through a pointer to char or unsigned char: int i = 0; char * c = reinterpret_cast<char*>(&i); // OK However, it is not clear to me if this is also allowed the other way around. For example: char * c = read_socket(...); unsigned * u = reinterpret_cast<unsigned*>(c); // huh? Summary of the answers The answer is NO for two reasons: You an only access an existing object as char*. There is no object in my sample code, only a byte buffer. The pointer address may not have the right alignment for the target object. In that case dereferencing it would result in undefined behavior. On the Intel and AMD platforms it will result performance overhead. On ARM it will trigger a CPU trap and your program will be terminated! This is a simplified explanation. For more detailed information see answers by @Luc Danton, @Cheers and hth. - Alf and @David Rodríguez.

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• What is better for a student programming in C++ to learn for writing GUI: C# vs QT?

  - by flashnik

  I'm a teacher(instructor) of CS in the university. The course is based on Cormen and Knuth and students program algorithms in C++. But sometimes it is good to show how an algorithm works or just a result of task through GUI. Also in my opinion it's very imporant to be able to write full programs. They will have courses concerning GUI but a three years, later, in fact, before graduatuion. I think that they should be able to write simple GUI applications earlier. So I want to teach them it. How do you think, what is more useful for them to learn: programming GUI with QT or writing GUI in C# and calling unmanaged C++ library? Update. For developing C++ applications students use MS Visual studio, so C# is already installed. But QT AFAIK also can be integrated into VS. I have following pros of C# (some were suggested there in answers): The need to make an additional layer. It's more work, but it forces you explicitly specify contract between GUI and processing data. The border between GUI and algorithms becomes very clear. It's more popular among employers. At least, in Russia where we live. It's rather common to write performance-critical algorithms in C++ and PInvoke them from well-looking C# application/ASP.Net website. Maybe it is not so widespread in the rest of the world but in Russia Windows is very popular, especially in companies and corporations due to some reasons, so most of b2b applications are Windows applications. Rapid development. It's much quicker to code in .Net then in C++ due to many reasons. And the con is that it's a new language with own specific for students. And the mess with invoking calls to library.

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• Using same log4j logger in standalone java application

  - by ktaylorjohn

  I have some code which is a standalone java application comprising of 30+ classes. Most of these inherit from some other base classes. Each and every class has this method to get and use a log4j logger public static Logger getLogger() { if (logger != null) return logger; try { PropertyUtil propUtil = PropertyUtil.getInstance("app-log.properties"); if (propUtil != null && propUtil.getProperties() != null) PropertyConfigurator.configure(propUtil.getProperties ()); logger = Logger.getLogger(ExtractData.class); return logger; } catch (Exception exception) { exception.printStackTrace(); } } A) My question is whether this should be refactored to some common logger which is initialized once and used across by all classes? Is that a better practice? B) If yes, how can this be done ? How can I pass the logger around ? C) This is actually being used in the code not as Logger.debug() but getLogger().debug(). What is the impact of this in terms of performance?

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• Rendering ListBox takes too long on Windows Phone

  - by Bhawk1990

  I am working on a Windows Phone 7 Application using Local SQLite Database and I'm having an issue with the rendering time of pages that use DataBinding. Currently it takes 60-70ms to retrieve the data from the database. Then it takes about 3100ms to render the data retrieved using a ListBox with DataBinding. Here you can see the DataTemplate of the ListBox: <DataTemplate x:Key="ListBoxItemTemplate"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="68" /> <ColumnDefinition /> </Grid.ColumnDefinitions> <TextBlock x:Name="TimeColumn" Text="{Binding TimeSpan}" Grid.Column="0" Grid.Row="0" Foreground="White" HorizontalAlignment="Center" VerticalAlignment="Center" /> <TextBlock Text="{Binding Stop.StopName}" Grid.Column="1" Grid.Row="0" Margin="15,0,0,0" TextWrapping="NoWrap" Foreground="Black" HorizontalAlignment="Left" VerticalAlignment="Center" /> </Grid> </DataTemplate> Comment: I have tried it using Canvas instead of Grid too, same result. Then, the database loads data into a CSList (using ViciCoolStorage) and that gets Binded to the ListBox: StationList.ItemsSource = App.RouteViewModel.RouteStops; Comment: I have tried to add the elements of the CSList to an ObservableCollection and bind that to the interface but didn't seem to change anything. Question: Am I doing something wrong that results in a huge load time - even if just loading 10 elements -, or this is normal? Do you have any recommendations to get a better performance with DataBinding? Thank you for your answers in advance!

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• How security of the systems might be improved using database procedures?

  - by Centurion

  The usage of Oracle PL/SQL procedures for controlling access to data often emphasized in PL/SQL books and other sources as being more secure approach. I'v seen several systems where all business logic related with data is performed through packages, procedures and functions, so application code becomes quite "dumb" and is only responsible for visualization part. I even heard some devs call such approaches and driving architects as database nazi :) because all logic code resides in database. I do know about DB procedure performance benefits, but now I'm interested in a "better security" when using thick client model. I assume such design mostly used when Oracle (and maybe MS SQL Server) databases are used. I do agree such approach improves security but only if there are not much users and every system user has a database account, so we might control and monitor data access through standard database user security. However, how such approach could increase the security for an average web system where thick clients are used: for example one database user with DML grants on all tables, and other users are handled using "users" and"user_rights" tables? We could use DB procedures, save usernames into context use that for filtering but vulnerability resides at the root - if the main database account is compromised than nothing will help. Of course in a real system we might consider at least several main users (for example frontend_db_user, backend_db_user).

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• Good Hosting Providers With Zend Framework Support

  - by manyxcxi

  I currently use ixwebhosting for my hosting services. They're cheap and work (most of the time). The databases are horribly slow, the servers are horribly slow, and their support (though usually prompt) is tough to deal with. That being said, they're cheap, I've got like 20 domains hosted in my account, none of them are high volume, and they work JUST good enough- until today. This isn't meant to be a condemnation of ixwh though. Their prices are very low for what they do offer and most things work just fine, most of the time. I need to be able to host web apps written with Zend Framework in a fairly easy fashion. The server performance can't be worse than what I've already had (a pretty low hurdle to clear), and I don't want to spend $30/mo. These are not money making websites- they're projects. My requirements are PHP 5.3, ZF support, MySQL databases, multiple domains- not much. Who should I look at, and who should I look out for? Also- I put this on SO instead of SF because of the Zend Framework specific requirement. If I'm wrong, do as you wish.

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• Is there a Java data structure that is effectively an ArrayList with double indicies and built-in in

  - by Bob Cross

  I am looking for a pre-built Java data structure with the following characteristics: It should look something like an ArrayList but should allow indexing via double-precision rather than integers. Note that this means that it's likely that you'll see indicies that don't line up with the original data points (i.e., asking for the value that corresponds to key "1.5"). As a consequence, the value returned will likely be interpolated. For example, if the key is 1.5, the value returned could be the average of the value at key 1.0 and the value at key 2.0. The keys will be sorted but the values are not ensured to be monotonically increasing. In fact, there's no assurance that the first derivative of the values will be continuous (making it a poor fit for certain types of splines). Freely available code only, please. For clarity, I know how to write such a thing. In fact, we already have an implementation of this and some related data structures in legacy code that I want to replace due to some performance and coding issues. What I'm trying to avoid is spending a lot of time rolling my own solution when there might already be such a thing in the JDK, Apache Commons or another standard library. Frankly, that's exactly the approach that got this legacy code into the situation that it's in right now.... Is there such a thing out there in a freely available library?

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• C Population Count of unsigned 64-bit integer with a maximum value of 15

  - by BitTwiddler1011

  I use a population count (hamming weight) function intensively in a windows c application and have to optimize it as much as possible in order to boost performance. More than half the cases where I use the function I only need to know the value to a maximum of 15. The software will run on a wide range of processors, both old and new. I already make use of the POPCNT instruction when Intel's SSE4.2 or AMD's SSE4a is present, but would like to optimize the software implementation (used as a fall back if no SSE4 is present) as much as possible. Currently I have the following software implementation of the function: inline int population_count64(unsigned __int64 w) { w -= (w 1) & 0x5555555555555555ULL; w = (w & 0x3333333333333333ULL) + ((w 2) & 0x3333333333333333ULL); w = (w + (w 4)) & 0x0f0f0f0f0f0f0f0fULL; return int(w * 0x0101010101010101ULL) 56; } So to summarize: (1) I would like to know if it is possible to optimize this for the case when I only want to know the value to a maximum of 15. (2) Is there a faster software implementation (for both Intel and AMD CPU's) than the function above?

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• Do I need to using locking against integers in c++ threads

  - by Shane MacLaughlin

  The title says it all really. If I am accessing a single integer type (e.g. long, int, bool, etc...) in multiple threads, do I need to use a synchronisation mechanism such as a mutex to lock them. My understanding is that as atomic types, I don't need to lock access to a single thread, but I see a lot of code out there that does use locking. Profiling such code shows that there is a significant performance hit for using locks, so I'd rather not. So if the item I'm accessing corresponds to a bus width integer (e.g. 4 bytes on a 32 bit processor) do I need to lock access to it when it is being used across multiple threads? Put another way, if thread A is writing to integer variable X at the same time as thread B is reading from the same variable, is it possible that thread B could end up a few bytes of the previous value mixed in with a few bytes of the value being written? Is this architecture dependent, e.g. ok for 4 byte integers on 32 bit systems but unsafe on 8 byte integers on 64 bit systems? Edit: Just saw this related post which helps a fair bit.

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• Moving x,y position of all array objects every frame in actionscript 3?

  - by Dylan Gallardo

  I have my code setup so that I have an movieclip in my library a class called "block" being duplicated multiple times and added into an array like this: function makeblock(e:Event){ newblock=new block; newblock.x=10; newblock.y=10; addChild(newblock); myarray[counter] = newblock; //adds a newblock object into array counter += 1; } Then I have a loop with a currently primitive way of handling my problem: stage.addEventListener(Event.ENTER_FRAME, gameloop); function gameloop(evt:Event):void { if (moveright==true){ myarray[0].x += 5; myarray[1].x += 5; myarray[2].x += 5 -(and so on)- My question is how can I change x,y values every frame for new objects duplicated into the array, along with the previous ones that were added. Of course with a more elegant way than writing it out myself... array[0].x += 5, array[1], array[2], array[3] etc. Ideally I would like this to go up to 500 or more array objects for one array so obviously I don't want to be writing it out individually haha, I also need it to be consistent with performance so using a for loop or something to loop through the whole array and move each x += 5 wouldn't work would it? Anyway, if anyone has any ideas that'd be great!

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• Domain model for an online WYSYWG webpage generator / runtime

  - by CharlieBrown

  Hi all, I'm using C#, MVC, NHibernate and StructureMap as my IoC container, and need some ideas regarding my domain model. The application I'm working has two parts: an Authoring part and a Runtime part. The idea is to allow the user to create a webpage in Authoring (mostly a form actually) by choosing from a set of predefined controls. That webpage will be later used as a form in a call center environment (Runtime part), or may be used in an intranet portal, etc. Basically something similar to what a CMS would do. The difference is, of course, that the webpage/form the author generates will be used and fulfilled in runtime, and that authros should be able to freely create the webpage they want without limitations. I have a draft working model that allows a RunController to iterate over the ScriptPage (my class for the "generated webpage") Controls collection and uses partial views to render each of them. Works kind of fine. Basically I have a common ScriptControl class, and then I can create for example a TextInputControl or a DropDownControl by inheriting from that base class. I can also figure out the Authoring part of the app, although that will surely be fun in itself for sure. :) The biggest problem I have now is persistance. In order to be flexible, I want to be able to add more controls, and template controls (think of an Address composite control) in sepparate DLLs, so I think having a relational model that handles very possible control is not the way to go. My current thinking is using a kind of ObjectStore: binary-serializing the ScriptPage object that contains the List collection and deserializing at Runtime, but I'm not sure how good will it work with NHibernate and how good the performance will be. Serializing a small "page" with 10 controls results in 7964 bytes, for example. Any ideas out there? Thanks in advance, excuse the length. ;)

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• Faster way to convert from a String to generic type T when T is a valuetype?

  - by Kumba

  Does anyone know of a fast way in VB to go from a string to a generic type T constrained to a valuetype (Of T as Structure), when I know that T will always be some number type? This is too slow for my taste: Return DirectCast(Convert.ChangeType(myStr, GetType(T)), T) But it seems to be the only sane method of getting from a String -- T. I've tried using Reflector to see how Convert.ChangeType works, and while I can convert from the String to a given number type via a hacked-up version of that code, I have no idea how to jam that type back into T so it can be returned. I'll add that part of the speed penalty I'm seeing (in a timing loop) is because the return value is getting assigned to a Nullable(Of T) value. If I strongly-type my class for a specific number type (i.e., UInt16), then I can vastly increase the performance, but then the class would need to be duplicated for each numeric type that I use. It'd almost be nice if there was converter to/from T while working on it in a generic method/class. Maybe there is and I'm oblivious to its existence?

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• Planning a programming project by example (C# or C++)

  - by Lunan

  I am in the last year of undergraduate degree and i am stumped by the lack of example in c++ and c# large project in my university. All the mini project and assignment are based on text based database, which is so inefficient, and console display and command, which is frustrating. I want to develop a complete prototype of corporate software which deals in Inventory, Sales, Marketing, etc. Everything you would usually find in SAP. I am grateful if any of you could direct me to a books or article or sample program. Some of the question are : How to plan for this kind of programming? should i use the concept of 1 object(such as inventory) have its own process and program and have an integrator sit for all the program, or should i integrate it in 1 big program? How to build and address a database? i have little bit knowledge in database and i know SQL but i never address database in a program before. Database are table, and how do you suppose to represent a table in a OOP way? For development type, which is better PHP and C++ or C# and ASP.NET? I am planning to use Web Interface to set form and information, but using a background program to handle the compute. .NET is very much integrated and coding should be much faster, but i really wonder about performance if compared to PHP and C++ package thank you for the info

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• Java: multi-threaded maps: how do the implementations compare?

  - by user346629

  I'm looking for a good hash map implementation. Specifically, one that's good for creating a large number of maps, most of them small. So memory is an issue. It should be thread-safe (though losing the odd put might be an OK compromise in return for better performance), and fast for both get and put. And I'd also like the moon on a stick, please, with a side-order of justice. The options I know are: HashMap. Disastrously un-thread safe. ConcurrentHashMap. My first choice, but this has a hefty memory footprint - about 2k per instance. Collections.sychronizedMap(HashMap). That's working OK for me, but I'm sure there must be faster alternatives. Trove or Colt - I think neither of these are thread-safe, but perhaps the code could be adapted to be thread safe. Any others? Any advice on what beats what when? Any really good new hash map algorithms that Java could use an implementation of? Thanks in advance for your input!

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• JMS message. Model to include data or pointers to data?

  - by John

  I am trying to resolve a design difference of opinion where neither of us has experience with JMS. We want to use JMS to communicate between a j2ee application and the stand-alone application when a new event occurs. We would be using a single point-to-point queue. Both sides are Java-based. The question is whether to send the event data itself in the JMS message body or to send a pointer to the data so that the stand-alone program can retrieve it. Details below. I have a j2ee application that supports data entry of new and updated persons and related events. The person records and associated events are written to an Oracle database. There are also stand-alone, separate programs that contribute new person and event records to the database. When a new event occurs through any of 5-10 different application functions, I need to notify remote systems through an outbound interface using an industry-specific standard messaging protocol. The outbound interface has been designed as a stand-alone application to support scalability through asynchronous operation and by moving it to a separate server. The j2ee application currently has most of the data in memory at the time the event is entered. The data would consist of approximately 6 different objects; a person object and some with multiple instances for an average size in the range of 3000 to 20,000 bytes. Some special cases could be many times this amount. From a performance and reliability perspective, should I model the JMS message to pass all the data needed to create the interface message, or model the JMS message to contain record keys for the data and have the stand-alone Java application retrieve the data to create the interface message?

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• Thread-Safe lazy instantiating using MEF

  - by Xaqron

  // Member Variable private static readonly object _syncLock = new object(); // Now inside a static method foreach (var lazyObject in plugins) { if ((string)lazyObject.Metadata["key"] = "something") { lock (_syncLock) { // It seems the `IsValueCreated` is not up-to-date if (!lazyObject.IsValueCreated) lazyObject.value.DoSomething(); } return lazyObject.value; } } Here I need synchronized access per loop. There are many threads iterating this loop and based on the key they are looking for, a lazy instance is created and returned. lazyObject should not be created more that one time. Although Lazy class is for doing so and despite of the used lock, under high threading I have more than one instance created (I track this with a Interlocked.Increment on a volatile static int and log it somewhere). The problem is I don't have access to definition of Lazy and MEF defines how the Lazy class create objects. I should notice the CompositionContainer has a thread-safe option in constructor which is already used. My questions: 1) Why the lock doesn't work ? 2) Should I use an array of locks instead of one lock for performance improvement ?

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• Adding variably named fields to Python classes

  - by Carson Myers

  I have a python class, and I need to add an arbitrary number of arbitrarily long lists to it. The names of the lists I need to add are also arbitrary. For example, in PHP, I would do this: class MyClass { } $c = new MyClass(); $n = "hello" $c.$n = array(1, 2, 3); How do I do this in Python? I'm also wondering if this is a reasonable thing to do. The alternative would be to create a dict of lists in the class, but since the number and size of the lists is arbitrary, I was worried there might be a performance hit from this. If you are wondering what I'm trying to accomplish, I'm writing a super-lightweight script interpreter. The interpreter walks through a human-written list and creates some kind of byte-code. The byte-code of each function will be stored as a list named after the function in an "app" class. I'm curious to hear any other suggestions on how to do this as well.

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• Stream buffering issue

  - by Kolyunya

  The mod_rewrite documentation states that it is a strict requirement to disable in(out)put buffering in a rewrite program. Keeping that in mind I've written a simple program (I do know that it lacks the EOF check but this is not an issue and it saves one condition check per loop): #include <stdio.h> #include <stdlib.h> int main ( void ) { setvbuf(stdin,NULL,_IOLBF,4200); setvbuf(stdout,NULL,_IOLBF,4200); int character; while ( 42 ) { character = getchar(); if ( character == '-' ) { character = '_'; } putchar(character); } return 42 - 42; } After making some measurements I was shocked - it was over 9,000 times slower than the demo Perl script provided by the documentation: #!/usr/bin/perl $| = 1; # Turn off I/O buffering while (<STDIN>) { s/-/_/g; # Replace dashes with underscores print $_; } Now I have two related questions: Question 1. I believe that the streams may be line buffered since Apache sends a new line after each path. Am I correct? Switching my program to setvbuf(stdin,NULL,_IOLBF,4200); setvbuf(stdout,NULL,_IOLBF,4200); makes it twice as fast as Perl one. This should not hit Apache's performance, should it? Question 2. How can one write a program in C which will use unbuffered streams (like Perl one) and will perform as fast as Perl one?

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• VB6 Game Development : Don't ask me why :-)

  - by CVS-2600Hertz-wordpress-com

  Hi All, I am developing a game in VB6 (plz don't ask me why :) ). The storyboard is ready and a rough implementation is underway. I am following a "pure-software-rendering" approach. (i.e. no DirectX, no openGL etc.) Amongst many others, the following "serious" problems exist: 2D alpha transparency reqd. to implement overlays. Parallax implementation to give depth-of-field illusion. Capturing mouse-scroll events globally (as in FPS-es; mapping them to changing weapon). Async sound play with absolute "zero-lag". Any ideas anyone. Please suggest any well documented library/ocx or sample-code. Plz do provide solutions with max performance and with as little overhead as possible. Also, anyone who has developed any games, and would be open to sharing her/his code would be highly appreciated. (any well-acknowledged VB games whose source-code i can study??) Thank You

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