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  • Optimizing MySQL for ALTER TABLE of InnoDB

    - by schuilr
    Sometime soon we will need to make schema changes to our production database. We need to minimize downtime for this effort, however, the ALTER TABLE statements are going to run for quite a while. Our largest tables have 150 million records, largest table file is 50G. All tables are InnoDB, and it was set up as one big data file (instead of a file-per-table). We're running MySQL 5.0.46 on an 8 core machine, 16G memory and a RAID10 config. I have some experience with MySQL tuning, but this usually focusses on reads or writes from multiple clients. There is lots of info to be found on the Internet on this subject, however, there seems to be very little information available on best practices for (temporarily) tuning your MySQL server to speed up ALTER TABLE on InnoDB tables, or for INSERT INTO .. SELECT FROM (we will probably use this instead of ALTER TABLE to have some more opportunities to speed things up a bit). The schema changes we are planning to do is adding a integer column to all tables and make it the primary key, instead of the current primary key. We need to keep the 'old' column as well so overwriting the existing values is not an option. What would be the ideal settings to get this task done as quick as possible?

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  • Set value of hidden field in a form using jQuery's ".val()" doesn't work !

    - by texens
    I've been trying to set the value of a hidden field in a form using jQuery, but without success. Here is a sample code that explains the problem. If I keep the input type to "text", it works without any trouble. But, changing the input type to "hidden", doesn't work ! <html> <head> <script type="text/javascript" src="jquery.js"></script> <script type="text/javascript"> $(document).ready(function(){ $("button").click(function(){ $("input:text#texens").val("tinkumaster"); }); }); </script> </head> <body> <p>Name: <input type="hidden" id="texens" name="user" value="texens" /></p> <button>Change value for the text field</button> </body> </html> I also tried the following workaround, by setting the input type to "text" and then using a "display:none" style for the input box. But, this also fails ! It seems jQuery has some trouble setting hidden or invisible input fields. Any ideas? Is there a workaround for this that actually works? Thanking in anticipation

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  • Where can I find a professional image gallery built on a javascript framework?

    - by user278457
    I'm looking to find a galleria replacement, hopefully using jQuery but other javascript frameworks such as prototype or mootools are fine too. I used galleria a while back, and I need a similar product now. Unfortunately, the devkick.com domain seems to have disappeared in the meantime and I'm wary of using products that aren't actively maintained. I'm willing to pay up to $50 per site for licensing costs, if the product meets my needs. I'm specifically looking for a gallery with the following features: Every image in the gallery preloads asap, not as the user clicks "next" Minimalist default css to keep my subsequent styling headaches down, preferably a "darkroom" style by default, much as galleria looks Each element that constructs the image gallery should be simple and logical to reference with CSS As easy to install as adding a css class to a single unordered list No dependencies other than the core jQuery/other library, including "easing" and other effects must be optional Works on browsers back to IE6, Firefox 3, Safari (and iPhone), Chrome, Opera Has a javascript API that lets me trigger callback functions on common events such as "user clicks next" or "image loads" degrades gracefully without javascript, either displays images as a list, or just displays the first image in the list bonus: The gallery can display other content, such as video or external sites, like the modal boxes at shadowbox-js.com well documented minimal bandwidth requirement - .js file should be ~10kb minified bonus: The gallery source is hosted on a reliable CDN like google's bonus: Thumbnails for images do not appear until the main image has loaded bonus: includes ability to set parameters with JSON to change common behaviours, such as slide/fade transitions or automatic image switch every X seconds

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  • NSOperation for animation loop causes strange scrolling behaviour

    - by Tricky
    Hi, I've created an animation loop which I run as an operation in order to keep the rest of my interface responsive. Whilst almost there, there is still one remaining issue. My UIScrollViews don't seem to be reliably picking up when a user touch ends. What this means is, for example, if a user drags down on a scroll view, when they lift their fingers the scrollview doesn't bounce back into place and the scrollbar remains visible. As if the finger hasn't left the screen. It takes another tap on the scrollview for it to snap to its correct position and the scrollbar to fade away... Here's the loop I created in a subclassed NSOperation: (void)main { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSRunLoop *runLoop = [NSRunLoop currentRunLoop]; _displayLink = [[CADisplayLink displayLinkWithTarget: self selector: @selector(animationLoop:)] retain]; [_displayLink setFrameInterval: 1.0f]; [_displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode: NSRunLoopCommonModes]; while (![self isCancelled]) { NSAutoreleasePool *loopPool = [[NSAutoreleasePool alloc] init]; [runLoop runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]]; [loopPool drain]; } [_displayLink invalidate]; [pool release]; } DOes anyone have any idea what might be going on here, and even better how to fix it... Thanks!

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  • Putting a C++ Vector as a Member in a Class that Uses a Memory Pool

    - by Deep-B
    Hey, I've been writing a multi-threaded DLL for database access using ADO/ODBC for use with a legacy application. I need to keep multiple database connections for each thread, so I've put the ADO objects for each connection in an object and thinking of keeping an array of them inside a custom threadInfo object. Obviously a vector would serve better here - I need to delete/rearrange objects on the go and a vector would simplify that. Problem is, I'm allocating a heap for each thread to avoid heap contention and stuff and allocating all my memory from there. So my question is: how do I make the vector allocate from the thread-specific heap? (Or would it know internally to allocate memory from the same heap as its wrapper class - sounds unlikely, but I'm not a C++ guy) I've googled a bit and it looks like I might need to write an allocator or something - which looks like so much of work I don't want. Is there any other way? I've heard vector uses placement-new for all its stuff inside, so can overloading operator new be worked into it? My scant knowledge of the insides of C++ doesn't help, seeing as I'm mainly a C programmer (even that - relatively). It's very possible I'm missing something elementary somewhere. If nothing easier comes up - I might just go and do the array thing, but hopefully it won't come to that. I'm using MS-VC++ 6.0 (hey, it's rude to laugh! :-P ). Any/all help will be much appreciated.

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  • Apache attack on compromised server, iframe injected by string replace

    - by Quang-Tuan Luong
    My server has been compromised recently. This morning, I have discovered that the intruder is injecting an iframe into each of my HTML pages. After testing, I have found out that the way he does that is by getting Apache (?) to replace every instance of <body> by <iframe link to malware></iframe></body> For example if I browse a file residing on the server consisting of: </body> </body> Then my browser sees a file consisting of: <iframe link to malware></iframe></body> <iframe link to malware></iframe></body> I have immediately stopped Apache to protect my visitors, but so far I have not been able to find what the intruder has changed on the server to perform the attack. I presume he has modified an Apache config file, but I have no idea which one. In particular, I have looked for recently modified files by time-stamp, but did not find anything noteworthy. Thanks for any help. Tuan. PS: I am in the process of rebuilding a new server from scratch, but in the while, I would like to keep the old one running, since this is a business site.

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  • Qt/MFC Migration Framework tool: properly exiting DLL?

    - by User
    I'm using the Qt/MFC Migration Framework tool following this example: http://doc.qt.nokia.com/solutions/4/qtwinmigrate/winmigrate-qt-dll-example.html The dll I build is loaded by a 3rd party MFC-based application. The 3rd party app basically calls one of my exported DLL functions to startup my plugin and another function to shutdown my application. Currently I'm doing nothing in my shutdown function. When I load my DLL in the 3rd party app the startup function is called and my DLL starts successfully and I can see my message box. However if I shutdown my plugin and then try to start it again I get the following error: Debug Error! Program: <my 3rd party app> Module: 4.7.1 File: global\qglobal.cpp Line: 2262 ASSERT failure in QWidget: "Widgets must be created in the GUI thread.", file kernel\qwidget.cpp line 1233 (Press Retry to debug the application) Abort Retry Ignore This makes me think I'm not doing something to properly shutdown my plugin. What do I need to do to shut it down properly? UPDATE: http://doc.qt.nokia.com/solutions/4/qtwinmigrate/winmigrate-walkthrough.html says: The DLL also has to make sure that it can be loaded together with other Qt based DLLs in the same process (in which case a QApplication object will probably exist already), and that the DLL that creates the QApplication object remains loaded in memory to avoid other DLLs using memory that is no longer available to the process. So I wonder if there is some problem where I need to somehow keep the original DLL loaded no matter what?

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  • TinyMce imagemanager won't generate image path when used with an iframe

    - by Tom
    I have successfully setup tinymce to work on a page within an iframe. Everything works perfectly. However, when you use imagemanager to pick an image to be inserted or replaced in the editor it will not copy the path(and filename) of the image to the "Image URL" input in the "Insert/edit image" box. The box will either remain empty or keep the address of the previous image. The behaviour is the same with the filemanager plugin. tinyMCE.init( { mode : "none", editor_selector : "mceEditor", theme : "advanced", plugins : "filemanager,imagemanager,autoresize,safari,pagebreak,style,layer,table,save,advhr,advimage,advlink,emotions,iespell,insertdatetime,preview,media,searchreplace,print,contextmenu,paste,directionality,fullscreen,noneditable,visualchars,nonbreaking,xhtmlxtras,template,inlinepopups,spellchecker", theme_advanced_buttons1 : "insertfile,insertimage,advimage,imagemanager,bold,italic,underline,|,justifyleft,justifycenter,justifyright,justifyfull,nonbreaking,cut,copy,paste,pastetext,pasteword,|,search,replace,|,bullist,numlist", theme_advanced_buttons2 : "blockquote,|,link,unlink,anchor,image,cleanup,help,code,|,insertdate,inserttime,|,forecolor,backcolor,|,charmap,iespell,media,advhr", theme_advanced_layout_manager : "SimpleLayout", theme_advanced_buttons3 : "tablecontrols,|,hr,removeformat,visualaid,|,sub,sup,strikethrough", theme_advanced_buttons4 : "styleselect,formatselect,fontselect,fontsizeselect,|,undo,redo,|,spellchecker", theme_advanced_toolbar_location : "external", theme_advanced_toolbar_align : "left", theme_advanced_statusbar_location : "bottom", relative_urls : true, document_base_url : "http://devtom.ecitb.org.uk/", auto_resize : true, content_css : "/custom/css/style.css", extended_valid_elements : "iframe[height|width|src|frameborder|scrolling]", }); /* The following code comes from- http://tinymce.moxiecode.com/punbb/viewtopic.php?id=12966 Without it the editor only loads 10% of the time. With it, it's pretty much 100% consistent. The other changes mentioned in the post have also been implemented. */ var setupTiny = function() { var ifrObj = document.getElementById('pageEditIFrame'); var win = ifrObj; if (win.contentWindow) { win = win.contentWindow; } var d; if(ifrObj.contentDocument) { d = ifrObj.contentDocument; } else if (ifrObj.contentWindow) { d = ifrObj.contentWindow.document; } else if (ifrObj.document) { d = ifrObj.document; } textAreas.each(function(txtEl) { tinyMCE.execCommand('mceAddFrameControl', false, { element_id : txtEl, window : win, doc : d }); }); }; //Waiting 1 second seems to make the editor load more reliably. setTimeout("setupTiny();",1000);

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  • Simplifying Testing through design considerations while utilizing dependency injection

    - by Adam Driscoll
    We are a few months into a green-field project to rework the Logic and Business layers of our product. By utilizing MEF (dependency injection) we have achieved high levels of code coverage and I believe that we have a pretty solid product. As we have been working through some of the more complex logic I have found it increasingly difficult to unit test. We are utilizing the CompositionContainer to query for types required by these complex algorithms. My unit tests are sometimes difficult to follow due to the lengthy mock object setup process that must take place, just right, to allow for certain circumstances to be verified. My unit tests often take me longer to write than the code that I'm trying to test. I realize this is not only an issue with dependency injection but with design as a whole. Is poor method design or lack of composition to blame for my overly complex tests? I've tried base classing tests, creating commonly used mock objects and ensuring that I utilize the container as much as possible to ease this issue but my tests always end up quite complex and hard to debug. What are some tips that you've seen to keep such tests concise, readable, and effective?

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  • Getting my foot in the SCADA door, how?

    - by bibby
    I keep hearing that I should learn SCADA and its PLC language to upgrade my career. While I enjoy currently being a web and mobile development privateer, the prospects of working for a municipality or industrial entity has its appeals (since I am trying to grow a family). Over the years, I've tought myself to skillfully use php, javascript, java, perl, awk, bash. Surely, these language skills can tranfer somewhat to SCADA's logic controller language. Without any formal training in CS (music major!) other than at the workplace, I wouldn't have been able to pick up those languages and run with them had it not been for their open documentation and free-to-install or already-installed interpreters/compilers. I can't see that this is true with SCADA, and I'm hoping that I'm wrong. Ideally, I'd like to be able to apply for a job that requires [A,B,C] and suggest that they hire me because I already know [A & B]; that they wouldn't have to do a ground-up training with someone that's never programmed before. So, finally, the question; How do I "learn" SCADA? Are there sites and docs? What's going to help me get my foot in the door? Any insight is appreciated. Thanks!

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  • Find all compilation errors in a Delphi project

    - by awmross
    I am doing some refactoring of my Delphi project. I want to be able to make a change, then see all the places in the project that break due to that change. Similar to how Eclipse lists all the compile errors for a project (in Java). In Delphi, I can make a change, then recompile my project, but the compiler stops when it finds the first Unit that does not compile. I have to fix that Unit, compile again, which will then show me the next error, etc etc. I want to be able to see all the compile errors in the project at once. Then I can decide if the change is worth doing or not. For example, if the change will require hand fixing of 50 separate source files, it's not worth doing. But if it only breaks 2 files then that's an easy change to make. Is there any way to do this in Delphi? Can I tell the compiler to keep going even after finding a Unit that does not compile? I am using Delphi 2010

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  • Filtering most out of XML with XSL?

    - by Gnudiff
    I need to transform a lot of XML files (Fedora export) into a different kind of XML. Trying to do it with XSL stylesheets and checking with the msxsl transformer. Supposedly I have xml file like this (assuming there are actually other nodes inside AAA, OBJ, amd all other nodes), Source.XML: <DOC> <AAA> <STUFF>example</STUFF> <OBJ> <OBJVERS id="A1" CREATED="2008-02-18T13:28:08.245Z"/> <OBJVERS id="A2" CREATED="2008-02-19T10:42:41.965Z"/> <OBJVERS id="A13" CREATED="2009-03-16T12:43:11.703Z"/> </OBJ> </AAA> <FFF/> <GGG/> <DDD> <FILE /> </DDD> </DOC> Which I need to look something like this (Target.XML): <MYOBJ> <ELEM>contents of OBJVERS with the biggest id OR creation date (whichever is easier to do) go here</ELEM> <IMAGE> contents of <FILE> node go here</IMAGE> </MYOBJ> The main problem that I have is that since I am new to XSL (and for this particular task do not have enough time to learn it properly) is that I can't understand how to tell XSL processor not to process anything else, I keep getting output from , for example. Update: basically, I solved this problem meanwhile. I will post my own answer and close the question. Update2: OK, Andrew's answer works, too, so I am just accepting it. :)

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  • Working with a database

    - by Susan
    I have an existing program for a bank account, the user can create an account then withdraw or deposit money to the account. As a transaction is processed, labels are being used to show the current information such as (Beginning Balance, Transaction Fee, Withdrawal Amount, and Ending Balance). Now, I need to be able to keep track of the transactions being processed in a SQL database. I know how to add a database to the project and then set it up to display all of the data from the table in a gridview. This is assuming that I manually entered data into the table; however, the table should be blank when the program starts and as I process transactions, then the data should be written to the table. How do I bind my existing fields (labels) to a datatable and send the text to the table. The book that I have is all related to just displaying the data that is already in the table and I have been through a couple of tutorial online and they seem to be about the same subject. I haven't found anything on how to do what I am looking for. Can someone help me out here. I don't mind references to other websites that might have the answer. Thanks, Susan

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  • A linked list with multiple heads in Java

    - by Emile
    Hi, I have a list in which I'd like to keep several head pointers. I've tried to create multiple ListIterators on the same list but this forbid me to add new elements in my list... (see Concurrent Modification exception). I could create my own class but I'd rather use a built-in implementation ;) To be more specific, here is an inefficient implementation of two basic operations and the one wich doesn't work : class MyList <E { private int[] _heads; private List<E _l; public MyList ( int nbHeads ) { _heads = new int[nbHeads]; _l = new LinkedList<E(); } public void add ( E e ) { _l.add(e); } public E next ( int head ) { return _l.get(_heads[head++]); // ugly } } class MyList <E { private Vector<ListIterator<E _iters; private List<E _l; public MyList ( int nbHeads ) { _iters = new Vector<ListIterator<E(nbHeads); _l = new LinkedList<E(); for( ListIterator<E iter : _iters ) iter = _l.listIterator(); } public void add ( E e ) { _l.add(e); } public E next ( int head ) { // ConcurrentModificationException because of the add() return _iters.get(head).next(); } } Emile

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  • How can I modify a scalar reference passed to a subroutine reference

    - by Mark
    I have a function to convert documents into different formats, which then calls another function based on the type document. It's pretty straight forward for everything aside from HTML documents which require a bit of cleaning up, and that cleaning up is different based on where it's come from. So I had the idea that I could pass a reference to a subroutine to the convert function so the caller has the opportunity to modify the HTML, kinda like so (I'm not at work so this isn't copy-and-pasted): package Converter; ... sub convert { my ($self, $filename, $coderef) = @_; if ($filename =~ /html?$/i) { $self->_convert_html($filename, $coderef); } } sub _convert_html { my ($self, $filename, $coderef) = @_; my $html = $self->slurp($filename); $coderef->(\$html); #this modifies the html $self->save_to_file($filename, $html); } which is then called by: Converter->new->convert("./whatever.html", sub { s/<html>/<xml>/i }); I've tried a couple of different things along these lines but I keep on getting 'Use of uninitialized value in substitution (s///)'. Is there any way of doing what I'm trying to do? Thanks

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  • Optimizing processing and management of large Java data arrays

    - by mikera
    I'm writing some pretty CPU-intensive, concurrent numerical code that will process large amounts of data stored in Java arrays (e.g. lots of double[100000]s). Some of the algorithms might run millions of times over several days so getting maximum steady-state performance is a high priority. In essence, each algorithm is a Java object that has an method API something like: public double[] runMyAlgorithm(double[] inputData); or alternatively a reference could be passed to the array to store the output data: public runMyAlgorithm(double[] inputData, double[] outputData); Given this requirement, I'm trying to determine the optimal strategy for allocating / managing array space. Frequently the algorithms will need large amounts of temporary storage space. They will also take large arrays as input and create large arrays as output. Among the options I am considering are: Always allocate new arrays as local variables whenever they are needed (e.g. new double[100000]). Probably the simplest approach, but will produce a lot of garbage. Pre-allocate temporary arrays and store them as final fields in the algorithm object - big downside would be that this would mean that only one thread could run the algorithm at any one time. Keep pre-allocated temporary arrays in ThreadLocal storage, so that a thread can use a fixed amount of temporary array space whenever it needs it. ThreadLocal would be required since multiple threads will be running the same algorithm simultaneously. Pass around lots of arrays as parameters (including the temporary arrays for the algorithm to use). Not good since it will make the algorithm API extremely ugly if the caller has to be responsible for providing temporary array space.... Allocate extremely large arrays (e.g. double[10000000]) but also provide the algorithm with offsets into the array so that different threads will use a different area of the array independently. Will obviously require some code to manage the offsets and allocation of the array ranges. Any thoughts on which approach would be best (and why)?

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  • Cocos2d shake/accelerometer issue.

    - by Ryan Poolos
    So I a little backstory. I wanted to implement a particle effect and sound effect that both last about 3 sec or so when the user shakes their iDevice. But first issue arrived when the build in UIEvent for shakes refused to work. So I took the advice of a few Cocos veterans to just use some script to get "violent" accelerometer inputs as shakes. Worked great until now. The problem is that if you keep shaking it just stacks the particle and sounds over and over. Now this wouldn't be that big of a deal except it happens even if you are careful to try and not do so. So what I am hoping to do is disable the accelerometer when the particle effect/sound effect start and then reenable it as soon as they finish. Now I don't know if I should do this by schedule, NStimer, or some other function. I am open to ALL suggestions. here is my current "shake" code. - (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration { const float violence = 1; static BOOL beenhere; BOOL shake = FALSE; if (beenhere) return; beenhere = TRUE; if (acceleration.x > violence * 1.5 || acceleration.x < (-1.5* violence)) shake = TRUE; if (acceleration.y > violence * 2 || acceleration.y < (-2 * violence)) shake = TRUE; if (acceleration.z > violence * 3 || acceleration.z < (-3 * violence)) shake = TRUE; if (shake) { id particleSystem = [CCParticleSystemQuad particleWithFile:@"particle.plist"]; [self addChild: particleSystem]; // Super simple Audio playback for sound effects! [[SimpleAudioEngine sharedEngine] playEffect:@"Sound.mp3"]; shake = FALSE; } beenhere = FALSE; }

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  • Email Tracking - GMail

    - by Abs
    Hello all, I am creating my own email tracking system for email marketing tracking. I have been able to determine each persons email client they are using by using the http referrer but for some reason GMAIL does not send a HTTP_REFERRER at all! So I am trying to find another way of identifying when gmail requests a transparent image from my server. I get the following headers print_r($_SERVER);: DOCUMENT_ROOT = /usr/local/apache/htdocs GATEWAY_INTERFACE = CGI/1.1 HTTP_ACCEPT = */* HTTP_ACCEPT_CHARSET = ISO-8859-1,utf-8;q=0.7,*;q=0.3 HTTP_ACCEPT_ENCODING = gzip,deflate,sdch HTTP_ACCEPT_LANGUAGE = en-GB,en-US;q=0.8,en;q=0.6 HTTP_CONNECTION = keep-alive HTTP_COOKIE = __utmz=156230011.1290976484.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utma=156230011.422791272.1290976484.1293034866.1293050468.7 HTTP_HOST = xx.xxx.xx.xxx HTTP_USER_AGENT = Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.237 Safari/534.10 PATH = /bin:/usr/bin QUERY_STRING = i=MTA= REDIRECT_STATUS = 200 REMOTE_ADDR = xx.xxx.xx.xxx REMOTE_PORT = 61296 REQUEST_METHOD = GET Is there anything of use in that list? Or is there something else I can do to actually get the http referrer, if not how are other ESPs managing to find whether gmail was used to view an email? Btw, I appreciate it if we can hold back on whether this is ethical or not as many ESPs do this already, I just don't want to pay for their service and I want to do it internally. Thanks all for any implementation advice. Update Just thought I would update this question and make it clearer in light of the bounty. I would like to find out when a user opens my email when sent to a GMail inbox. Assume, I have the usual transparent image tracking and the user does not block images. I would like to do this with the single request and the header details I get when the transparent image is requested.

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  • How to cache pages using background jobs ?

    - by Alexandre
    Definitions: resource = collection of database records, regeneration = processing these records and outputting the corresponding html Current flow: Receive client request Check for resource in cache If not in cache or cache expired, regenerate Return result The problem is that the regeneration step can tie up a single server process for 10-15 seconds. If a couple of users request the same resource, that could result in a couple of processes regenerating the exact same resource simultaneously, each taking up 10-15 seconds. Wouldn't it be preferrable to have the frontend signal some background process saying "Hey, regenerate this resource for me". But then what would it display to the user? "Rebuilding" is not acceptable. All resources would have to be in cache ahead of time. This could be a problem as the database would almost be duplicated on the filesystem (too big to fit in memory). Is there a way to avoid this? Not ideal, but it seems like the only way out. But then there's one more problem. How to keep the same two processes from requesting the regeneration of a resource at the same time? The background process could be regenerating the resource when a frontend asks for the regeneration of the same resource. I'm using PHP and the Zend Framework just in case someone wants to offer a platform-specific solution. Not that it matters though - I think this problem applies to any language/framework. Thanks!

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  • Serial: write() throttling?

    - by damian
    Hi everyone, I'm working on a project sending serial data to control animation of LED lights, which need to stay in sync with a sound engine. There seems to be a large serial write buffer (OSX (POSIX) + FTDI chipset usb serial device), so without manually restricting the transmission rate, the animation system can get several seconds ahead of the serial transmission. Currently I'm manually restricting the serial write speed to the baudrate (8N1 = 10 bytes serial frame per 8 bytes data, 19200 bps serial - 1920 bytes per second max), but I am having a problem with the sound drifting out of sync over time - it starts fine, but after 10 minutes there's a noticeable (100ms+) lag between the sound and the lights. This is the code that's restricting the serial write speed (called once per animation frame, 'elapsed' is the duration of the current frame, 'baudrate' is the bps (19200)): void BufferedSerial::update( float elapsed ) { baud_timer += elapsed; if ( bytes_written > 1024 ) { // maintain baudrate float time_should_have_taken = (float(bytes_written)*10)/float(baudrate); float time_actually_took = baud_timer; // sleep if we have > 20ms lag between serial transmit and our write calls if ( time_should_have_taken-time_actually_took > 0.02f ) { float sleep_time = time_should_have_taken - time_actually_took; int sleep_time_us = sleep_time*1000.0f*1000.0f; //printf("BufferedSerial::update sleeping %i ms\n", sleep_time_us/1000 ); delayUs( sleep_time_us ); // subtract 128 bytes bytes_written -= 128; // subtract the time it should have taken to write 128 bytes baud_timer -= (float(128)*10)/float(baudrate); } } } Clearly there's something wrong, somewhere. A much better approach would be to be able to determine the number of bytes currently in the transmit queue, and try and keep that below a fixed threshold. Any advice appreciated.

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  • C# reference collection for storing reference types

    - by ivo s
    I like to implement a collection (something like List<T>) which would hold all my objects that I have created in the entire life span of my application as if its an array of pointers in C++. The idea is that when my process starts I can use a central factory to create all objects and then periodically validate/invalidate their state. Basically I want to make sure that my process only deals with valid instances and I don't re-fetch information I already fetched from the database. So all my objects will basically be in one place - my collection. A cool thing I can do with this is avoid database calls to get data from the database if I already got it (even if I updated it after retrieval its still up-to-date if of course some other process didn't update it but that a different concern). I don't want to be calling new Customer("James Thomas"); again if I initted James Thomas already sometime in the past. Currently I will end up with multiple copies of the same object across the appdomain - some out of sync other in sync and even though I deal with this using timestamp field on the MSSQL server I'd like to keep only one copy per customer in my appdomain (if possible process would be better). I can't use regular collections like List or ArrayList for example because I cannot pass parameters by their real local reference to the their existing Add() methods where I'm creating them using ref so that's not to good I think. So how can this be implemented/can it be implemented at all ? A 'linked list' type of class with all methods working with ref & out params is what I'm thinking now but it may get ugly pretty quickly. Is there another way to implement such collection like RefList<T>.Add(ref T obj)? So bottom line is: I don't want re-create an object if I've already created it before during the entire application life unless I decide to re-create it explicitly (maybe its out-of-date or something so I have to fetch it again from the db). Is there alternatives maybe ?

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  • What java web application framework to use?

    - by frohiky
    One of the main products of my company is an Oracle Forms (and Reports) based application, that "needs" to be re-written in another technology. Why? Users want a more rich interface experience, and we want, preferably, to reduce costs with an open source application server. For this (HUGE) project, we intend to use a java web application framework, keep these points in mind: We have: hundreds of tables on our database (the ORM must be as flexible as possible); some logic which is (and will still be) based on PL/SQL procedures/functions/packages; a lot of CRUDs (the application itself is of an considerable size); a demand to work with/generate documents and workflows; an intranet based user environment; We want: to offer a RIA interface experience; use (if possible) an open source app server; a rapid (as possible) development framework; a somewhat mature framework with a "wise" roadmap (and a considerable community support); a MVC approach combined with JS or GWT widgets (e.g. Vaadin or SmartGWT); Well, in the past weeks I've read a lot of posts, Q&As on stackoverflow, and much more: Wicket, JSF, Tapestry, Grails, GWT, Struts2, Play, Spring, Seam, Echo, .... the list goes on! I've even researched about Alfresco..! The obvious question: Which one to use? At this time, any insight, recommendation, shared experience, advice will be more then welcome!

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  • Switching textstorage of NSTextViews back and forth

    - by Jakob Dam Jensen
    I'm trying to make a feature in a product which gives the user the ability to split a textview into two. The way this is done is by removing the textview from it's superview, making a NSSplitView and adding the textview as well as a new NSTextView instance to this splitview. Lastly I make these two textviews share the same textstorage in order to make them share the same content. It works great. But the problem is when I want to make one of the two textviews change textstorage. The replaceTextStorage method in NSLayoutManager causes both NSTextView to change textStorage. The API documentation states: replaceTextStorage: All NSLayoutManager objects sharing the original NSTextStorage object then share the new one. This method makes all the adjustments necessary to keep these relationships intact, unlike setTextStorage:. So it makes sense that it would do this. But the question is how do I make it possible to have two (or more) textviews first share the same storage and after that having them using their own? I've tried replacing the layoutManager and even making new instances of NSTextViews but no luck... Any suggestions?

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  • Do I need Response.End() in ASP.Net 2.0

    - by Hamish Grubijan
    Hi, I am just starting with ASP.Net. I copied a ex-co-worker's code (from .Net 1.1 era) and it has a Response.End(); in case of an error. There is also a: catch (Exception ex) { Response.Write(ex.Message); Response.End(); } at the end of Page_Load(object sender, System.EventArgs e) which always appends "Thread was aborted." or something like that at the end. I suspect that this worked differently before, or the error conditions were not tested very well. Anyhow, I was able to stop using Response.End(); in case when I do not like the GET parameters, and use return; instead. It seemed to do the right think in a simple case. Is this Ok in general? There are some problems with the code I copied, but I do not want to do a rewrite; I just want to get it running first and find wrinkles later. The Response.End(); caused a mental block for me, however, so I want to figure it out. I want to keep the catch all clause just in case, at least for now. I could also end the method with: catch (System.Threading.ThreadAbortException) { Response.End(); } catch (Exception ex) { Response.Write(ex.Message); Response.End(); } but that just seems extremely stupid, once you think about all of the exceptions being generated. Please give me a few words of wisdom. Feel free to ask if something is not clear. Thanks! P.S. Ex-coworker was not fired and is a good coder - one more reason to reuse his example.

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  • generating and unmarshalling java classes while unmarshalling input contains a DTD

    - by Hans Westerbeek
    Hi, For a Spring-based project, I have the following situation to solve: I have XML files coming in whose contents I will have to parse at runtime. Those XML files come with a DTD reference. I need to generate the classes that the unmarshaller churns out using the right at build time, using the Maven2 plugin for the unmarshalling library of choice. This is also not very hard to do, once I have generated an XSD from the DTD. I want to use spring-oxm's UnMarshaller interface to do the unmarshalling at runtime. This I understand how to do. The xml files come in with a DTD reference, and all unmarshalling libraries out there want to do unmarshalling based on an XSD. Now, as described in the castor documentation, I can convert the DTD to an XSD and keep it on the classpath. However, when an actual XML file comes into the system it will still have that DTD reference at the top, and there's nothing I can really do about that (except for string replacing which feels hacky in this case). Will this cause the unmarshaller, like Castor to fail? Am I right in suspecting that this DTD reference will cause the unmarshalling to fail? Could I do pure DTD-based unmarshalling? Or can this somehow be prevented by providing detailed configuration to the unmarshaller? Until now, I have tried castor, xmlbeans and xstream. Which would fit my purposes best? Has anyone else been in this situation? Did you also end up just doing manual DOM or SAX parsing?

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