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  • How to provide js-ctypes in a spidermonkey embedding?

    - by Triston J. Taylor
    Summary I have looked over the code the SpiderMonkey 'shell' application uses to create the ctypes JavaScript object, but I'm a less-than novice C programmer. Due to the varying levels of insanity emitted by modern build systems, I can't seem to track down the code or command that actually links a program with the desired functionality. method.madness This js-ctypes implementation by The Mozilla Devs is an awesome addition. Since its conception, scripting has been primarily used to exert control over more rigorous and robust applications. The advent of js-ctypes to the SpiderMonkey project, enables JavaScript to stand up and be counted as a full fledged object oriented rapid application development language flying high above 'the bar' set by various venerable application development languages such as Microsoft's VB6. Shall we begin? I built SpiderMonkey with this config: ./configure --enable-ctypes --with-system-nspr followed by successful execution of: make && make install The js shell works fine and a global ctypes javascript object was verified operational in that shell. Working with code taken from the first source listing at How to embed the JavaScript Engine -MDN, I made an attempt to instantiate the JavaScript ctypes object by inserting the following code at line 66: /* Populate the global object with the ctypes object. */ if (!JS_InitCTypesClass(cx, global)) return NULL; /* I compiled with: g++ $(./js-config --cflags --libs) hello.cpp -o hello It compiles with a few warnings: hello.cpp: In function ‘int main(int, const char**)’: hello.cpp:69:16: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null] hello.cpp:80:20: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] hello.cpp:89:17: warning: NULL used in arithmetic [-Wpointer-arith] But when you run the application: ./hello: symbol lookup error: ./hello: undefined symbol: JS_InitCTypesClass Moreover JS_InitCTypesClass is declared extern in 'dist/include/jsapi.h', but the function resides in 'ctypes/CTypes.cpp' which includes its own header 'CTypes.h' and is compiled at some point by some command during 'make' to yeild './CTypes.o'. As I stated earlier, I am less than a novice with the C code, and I really have no idea what to do here. Please give or give direction to a generic example of making the js-ctypes object functional in an embedding.

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  • Creating a smart text generator

    - by royrules22
    I'm doing this for fun (or as 4chan says "for teh lolz") and if I learn something on the way all the better. I took an AI course almost 2 years ago now and I really enjoyed it but I managed to forget everything so this is a way to refresh that. Anyway I want to be able to generate text given a set of inputs. Basically this will read forum inputs (or maybe Twitter tweets) and then generate a comment based on the learning. Now the simplest way would be to use a Markov Chain Text Generator but I want something a little bit more complex than that as the MKC basically only learns by word order (which word is more likely to appear after word x given the input text). I'm trying to see if there's something I can do to make it a little bit more smarter. For example I want it to do something like this: Learn from a large selection of posts in a message board but don't weight it too much For each post: Learn from the other comments in that post and weigh these inputs higher Generate comment and post See what other users' reaction to your post was. If good weigh it positively so you make more posts that are similar to the one made, and vice versa if negative. It's the weighing and learning from mistakes part that I'm not sure how to implement. I thought about Artificial Neural Networks (mainly because I remember enjoying that chapter) but as far as I can tell that's mainly used to classify things (i.e. given a finite set of choices [x1...xn] which x is this given input) not really generate anything. I'm not even sure if this is possible or if it is what should I go about learning/figuring out. What algorithm is best suited for this? To those worried that I will use this as a bot to spam or provide bad answers to SO, I promise that I will not use this to provide (bad) advice or to spam for profit. I definitely will not post it's nonsensical thoughts on SO. I plan to use it for my own amusement. Thanks!

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  • How to replace custom IDs in the order of their appearance with a shell script?

    - by Péter Török
    I have a pair of rather large log files with very similar content, except that some identifiers are different between the two. A couple of examples: UnifiedClassLoader3@19518cc | UnifiedClassLoader3@d0357a JBossRMIClassLoader@13c2d7f | JBossRMIClassLoader@191777e That is, wherever the first file contains UnifiedClassLoader3@19518cc, the second contains UnifiedClassLoader3@d0357a, and so on. I want to replace these with identical IDs so that I can spot the really important differences between the two files. I.e. I want to replace all occurrences of both UnifiedClassLoader3@19518cc in file1 and UnifiedClassLoader3@d0357a in file2 with UnifiedClassLoader3@1; all occurrences of both JBossRMIClassLoader@13c2d7f in file1 and JBossRMIClassLoader@191777e in file2 with JBossRMIClassLoader@2 etc. Using the Cygwin shell, so far I managed to list all different identifiers occurring in one of the files with grep -o -e 'ClassLoader[0-9]*@[0-9a-f][0-9a-f]*' file1.log | sort | uniq However, now the original order is lost, so I don't know which is the pair of which ID in the other file. With grep -n I can get the line number, so the sort would preserve the order of appearance, but then I can't weed out the duplicate occurrences. Unfortunately grep can not print only the first match of a pattern. I figured I could save the list of identifiers produced by the above command into a file, then iterate over the patterns in the file with grep -n | head -n 1, concatenate the results and sort them again. The result would be something like 2 ClassLoader3@19518cc 137 ClassLoader@13c2d7f 563 ClassLoader3@1267649 ... Then I could (either manually or with sed itself) massage this into a sed command like sed -e 's/ClassLoader3@19518cc/ClassLoader3@2/g' -e 's/ClassLoader@13c2d7f/ClassLoader@137/g' -e 's/ClassLoader3@1267649/ClassLoader3@563/g' file1.log > file1_processed.log and similarly for file2. However, before I start, I would like to verify that my plan is the simplest possible working solution to this. Is there any flaw in this approach? Is there a simpler way?

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  • DataGrid: dynamic DataTemplate for dynamic DataGridTemplateColumn

    - by Lukas Cenovsky
    I want to show data in a datagrid where the data is a collection of public class Thing { public string Foo { get; set; } public string Bar { get; set; } public List<Candidate> Candidates { get; set; } } public class Candidate { public string FirstName { get; set; } public string LastName { get; set; } ... } where the number of candidates in Candidates list varies at runtime. Desired grid layout looks like this Foo | Bar | Candidate 1 | Candidate 2 | ... | Candidate N I'd like to have a DataTemplate for each Candidate as I plan changing it during runtime - user can choose what info about candidate is displayed in different columns (candidate is just an example, I have different object). That means I also want to change the column templates in runtime although this can be achieved by one big template and collapsing its parts. I know about two ways how to achieve my goals (both quite similar): Use AutoGeneratingColumn event and create Candidates columns Add Columns manually In both cases I need to load the DataTemplate from string with XamlReader. Before that I have to edit the string to change the binding to wanted Candidate. Is there a better way how to create a DataGrid with unknown number of DataGridTemplateColumn? Note: This question is based on dynamic datatemplate with valueconverter

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  • Grails or Play! for an ex-RoR developer ?

    - by Kedare
    Hello, I plan to begin learning a Java web framework (I love the Java API), I already used Rails and Django. I want something close to Java, but without all the complexity of J2EE. I've found 2 framework that could be good for me : Grails : Grails looks great, it use Groovy that is better than Java for web application (I think..), but it's slower, that use pure-java components (Hibernate, Strut, Spring), it looks pretty simple to deploy (send .war and it's ok !), the GSP is great ! It's a bit harder to debug (need to restart the server at each modification, and the stacktrace is a mix of Java and Groovy stack that is not always understandable..) Play! : This framework also looks great, it's faster than Grails (It's use directly Java), but I don't really like how it use Java, it modify the source code to transform the properties call as setXXX/getXXX, I'm not kind of that... The framework also have caching function that Grails don't (alreary) has. I don't really like the Template Engine. It's also easer to debug (no need to restart the server, and the stacktrace is clear) What do you recommend for ? I am looking for something easy to learn (I used a lot ruby and java, but a little bit java (But I love the Java API)), that is full featured (That's no a problem with all the Java Library availables, but if it's bundle and integrated I prefer), that scale and that is not too slow (faster than ruby), and if possible I would want something with a decent community to easily find support and answer to my questions ;) PS: No JRuby on Rails Thank you !

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  • Does ASP.NET need to be configured for Full Trust to implement 'PageHandlerFactory' ?

    - by Kev
    Our hosting platform (running IIS6/ASP.NET 2.0) is configured to run under partial trust. In the machine wide web.config file we set the ASP.NET trust level to Medium (and lock to prevent overrides) and use a modified policy file. When trying to add a custom HttpHandler to handle .aspx requests for a website running in this configuration I get the following security exception: Security Exception Description: The application attempted to perform an operation not allowed by the security policy. To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file. Exception Details: System.Security.SecurityException: Request failed. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [SecurityException: Request failed.] System.Reflection.Assembly._GetType(String name, Boolean throwOnError, Boolean ignoreCase) +0 System.Reflection.Assembly.GetType(String name, Boolean throwOnError, Boolean ignoreCase) +42 System.Web.Compilation.CompilationUtil.GetTypeFromAssemblies(AssemblyCollection assembliesCollection, String typeName, Boolean ignoreCase) +172 System.Web.Compilation.BuildManager.GetType(String typeName, Boolean throwOnError, Boolean ignoreCase) +291 System.Web.Configuration.ConfigUtil.GetType(String typeName, String propertyName, ConfigurationElement configElement, XmlNode node, Boolean checkAptcaBit, Boolean ignoreCase) +52 I'm using a class derived from PageHandlerFactory, for example: public class MyPageHandlerFactory : PageHandlerFactory { public override System.Web.IHttpHandler GetHandler(System.Web.HttpContext context, string requestType, string virtualPath, string path) { // CustomPageHandler derives from System.Web.UI.Page return new CustomPageHandler(); } } My web.config httpHandler configuration is as follow: <httpHandlers> <add verb="*" path="*.aspx" type="MyPageHandler.MyPageHandlerFactory" /> </httpHandlers> The documentation for PageHandlerFactory shows that PageHandlerFactory is decorated with the following attributes: [PermissionSetAttribute(SecurityAction.LinkDemand, Unrestricted = true)] [PermissionSetAttribute(SecurityAction.InheritanceDemand, Unrestricted = true)] public class PageHandlerFactory : IHttpHandlerFactory Does this mean that I need to set ASP.NET to run at Full Trust to be able to create my own PageHandlerFactory classes?

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  • Add Keyboard Binding To Existing Emacs Mode

    - by Sean M
    I'm attempting my first modification of emacs. I recorded a little keyboard macro and had emacs spit it out as elisp, resulting in: (setq add-docstring "\C-rdef\C-n\C-a\C-m\C-p\C-i\C-u6\"\C-u3\C-b") (global-set-key "\C-c\C-d" 'add-docstring) Searching the emacs reference, though, revealed that C-c C-d is already bound in diff mode. I don't plan on using diff mode, but the future is unknowable and I'd like to not lay a trap for myself. So I'd like this keybinding to only operate in python mode, where it tries to help me add docstrings. In my /usr/share/emacs/23.whatever/list/progmodes, I found python.elc and python.el.gz. I unzipped python.el.gz and got a readable version of the elisp file. Now, though, the documentation becomes opaque to me. How can I add my key binding to the python mode, instead of globally? Is it possible, for bonus points, to apply the changes to python mode without restarting emacs or closing open files? It's the self-modifying editor, I figure there's a good chance that it's possible.

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  • Long running transactions with Spring and Hibernate?

    - by jimbokun
    The underlying problem I want to solve is running a task that generates several temporary tables in MySQL, which need to stay around long enough to fetch results from Java after they are created. Because of the size of the data involved, the task must be completed in batches. Each batch is a call to a stored procedure called through JDBC. The entire process can take half an hour or more for a large data set. To ensure access to the temporary tables, I run the entire task, start to finish, in a single Spring transaction with a TransactionCallbackWithoutResult. Otherwise, I could get a different connection that does not have access to the temporary tables (this would happen occasionally before I wrapped everything in a transaction). This worked fine in my development environment. However, in production I got the following exception: java.sql.SQLException: Lock wait timeout exceeded; try restarting transaction This happened when a different task tried to access some of the same tables during the execution of my long running transaction. What confuses me is that the long running transaction only inserts or updates into temporary tables. All access to non-temporary tables are selects only. From what documentation I can find, the default Spring transaction isolation level should not cause MySQL to block in this case. So my first question, is this the right approach? Can I ensure that I repeatedly get the same connection through a Hibernate template without a long running transaction? If the long running transaction approach is the correct one, what should I check in terms of isolation levels? Is my understanding correct that the default isolation level in Spring/MySQL transactions should not lock tables that are only accessed through selects? What can I do to debug which tables are causing the conflict, and prevent those tables from being locked by the transaction?

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  • Stored procedure using cursor in mySql.

    - by RAVI
    I wrote a stored procedure using cursor in mysql but that procedure is taking 10 second to fetch the result while that result set have only 450 records so, I want to know that why that proedure is taking that much time to fetch tha record. procedure as below: DELIMITER // DROP PROCEDURE IF EXISTS curdemo123// CREATE PROCEDURE curdemo123(IN Branchcode int,IN vYear int,IN vMonth int) BEGIN DECLARE EndOfData,tempamount INT DEFAULT 0; DECLARE tempagent_code,tempplantype,tempsaledate CHAR(12); DECLARE tempspot_rate DOUBLE; DECLARE var1,totalrow INT DEFAULT 1; DECLARE cur1 CURSOR FOR select SQL_CALC_FOUND_ROWS ad.agentCode,ad.planType,ad.amount,ad.date from adplan_detailstbl ad where ad.branchCode=Branchcode and (ad.date between '2009-12-1' and '2009-12-31')order by ad.NUM_ID asc; DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET EndOfData = 1; DROP TEMPORARY TABLE IF EXISTS temptable; CREATE TEMPORARY TABLE temptable (agent_code varchar(15), plan_type char(12),sale double,spot_rate double default '0.0', dATE DATE); OPEN cur1; SET totalrow=FOUND_ROWS(); while var1 <= totalrow DO fetch cur1 into tempagent_code,tempplantype,tempamount,tempsaledate; IF((tempplantype='Unit Plan' OR tempplantype='MIP') OR tempplantype='STUP') then select spotRate into tempspot_rate from spot_amount where ((monthCode=vMonth and year=vYear) and ((agentCode=tempagent_code and branchCode=Branchcode) and (planType=tempplantype))); INSERT INTO temptable VALUES(tempagent_code,tempplantype,tempamount,tempspot_rate,tempsaledate); else INSERT INTO temptable(agent_code,plan_type,sale,dATE) VALUES(tempagent_code,tempplantype,tempamount,tempsaledate); END IF; SET var1=var1+1; END WHILE; CLOSE cur1; select * from temptable; DROP TABLE temptable; END // DELIMITER ;

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  • Java webapp: how to implement a web bug (1x1 pixel)?

    - by NoozNooz42
    In the accepted answer in the following question, a SO regular with 13K+ rep suggests to use a "web bug" (non-cacheable 1x1 img) to be able to track requests in the logs: http://stackoverflow.com/questions/1784893 How can I do this in Java? Basically, I've got two issues: how to make sure the 1x1 image is not cacheable (how to set the header)? how to make sure the query for these 1x1 image will appear in the logs? I'm looking for exact piece of code because I know how to write a .jsp/servlet and I know how to serve an 1x1 image :) My question is really about the exact .jsp/servlet that I should write and how/what needs to be done so that Tomcat logs the request. For example I plan to use the following mapping: <servlet-mapping> <servlet-name>WebBugServlet</servlet-name> <url-pattern>/webbug*</url-pattern> </servlet-mapping> and then use an img tag referencing a "webbug.png" (or .gif), so how do I write the .jsp/servlet? What/where should I look for in the logs?

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  • Scapy install issues. Nothing seems to actually be installed?

    - by Chris
    I have an apple computer running Leopard with python 2.6. I downloaded the latest version of scapy and ran "python setup.py install". All went according to plan. Now, when I try to run it in interactive mode by just typing "scapy", it throws a bunch of errors. What gives! Just in case, here is the FULL error message.. INFO: Can't import python gnuplot wrapper . Won't be able to plot. INFO: Can't import PyX. Won't be able to use psdump() or pdfdump(). ERROR: Unable to import pcap module: No module named pcap/No module named pcapy ERROR: Unable to import dnet module: No module named dnet Traceback (most recent call last): File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/runpy.py", line 122, in _run_module_as_main "__main__", fname, loader, pkg_name) File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/runpy.py", line 34, in _run_code exec code in run_globals File "/Users/owner1/Downloads/scapy-2.1.0/scapy/__init__.py", line 10, in <module> interact() File "scapy/main.py", line 245, in interact scapy_builtins = __import__("all",globals(),locals(),".").__dict__ File "scapy/all.py", line 25, in <module> from route6 import * File "scapy/route6.py", line 264, in <module> conf.route6 = Route6() File "scapy/route6.py", line 26, in __init__ self.resync() File "scapy/route6.py", line 39, in resync self.routes = read_routes6() File "scapy/arch/unix.py", line 147, in read_routes6 lifaddr = in6_getifaddr() File "scapy/arch/unix.py", line 123, in in6_getifaddr i = dnet.intf() NameError: global name 'dnet' is not defined

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  • PHP Database connection practice

    - by Phill Pafford
    I have a script that connects to multiple databases (Oracle, MySQL and MSSQL), each database connection might not be used each time the script runs but all could be used in a single script execution. My question is, "Is it better to connect to all the databases once in the beginning of the script even though all the connections might not be used. Or is it better to connect to them as needed, the only catch is that I would need to have the connection call in a loop (so the database connection would be new for X amount of times in the loop). Yeah Example Code #1: // Connections at the beginning of the script $dbh_oracle = connect2db(); $dbh_mysql = connect2db(); $dbh_mssql = connect2db(); for ($i=1; $i<=5; $i++) { // NOTE: might not use all the connections $rs = queryDb($query,$dbh_*); // $dbh can be any of the 3 connections } Yeah Example Code #2: // Connections in the loop for ($i=1; $i<=5; $i++) { // NOTE: Would use all the connections but connecting multiple times $dbh_oracle = connect2db(); $dbh_mysql = connect2db(); $dbh_mssql = connect2db(); $rs_oracle = queryDb($query,$dbh_oracle); $rs_mysql = queryDb($query,$dbh_mysql); $rs_mssql = queryDb($query,$dbh_mssql); } now I know you could use a persistent connection but would that be one connection open for each database in the loop as well? Like mysql_pconnect(), mssql_pconnect() and adodb for Oracle persistent connection method. I know that persistent connection can also be resource hogs and as I'm looking for best performance/practice.

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  • How to get resultset with stored procedure calls over two linked servers?

    - by räph
    I have problems filling a temporary table with the resultset from a procedure call on a linked server, in which again a procedure on another server is called. I have a Stored Procedure sproc1 with the following code, which calls another procedure sproc2 on a linked server. SET @sqlCommand = 'INSERT INTO #tblTemp ( ModuleID, ParamID) ' + '( SELECT * FROM OPENQUERY(' + @targetServer + ', ' + '''SET FMTONLY OFF; EXEC ' + @targetDB + '.usr.sproc2 ' + @param + ''' ) )' exec ( @sqlCommand ) Now in the called sproc2 I again call a third procedure sproc3 on another linked server, which returns my resultset. SET @sqlCommand = 'EXEC ' + @targetServer +'.database.usr.sproc3 ' + @param exec ( @sqlCommand ) The whole thing doen't work, as I get an SQL error 7391 The operation could not be performed because OLE DB provider "%ls" for linked server "%ls" was unable to begin a distributed transaction. I already checked the hints at this microsoft article, but without success. But maybe, I can change the code in sproc1. Would there be some alternative to the temp table and the open query? Just calling stored procedures from server A to B to C and returning the resultset is working (I do this often in the application). But this special case with the temp table and openquery doesn't work! Or is it just not possible what I am trying to do? The microsft article states: Check the object you refer on the destination server. If it is a view or a stored procedure, or causes an execution of a trigger, check whether it implicitly references another server. If so, the third server is the source of the problem. Run the query directly on the third server. If you cannot run the query directly on the third server, the problem is not actually with the linked server query. Resolve the underlying problem first. Is this my case? PS: I can't avoid the architecture with the three servers.

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  • Using unset member variables within a class or struct

    - by Doug Kavendek
    It's pretty nice to catch some really obvious errors when using unset local variables or when accessing a class or struct's members directly prior to initializing them. In visual studio 2008 you get an "uninitialized local variable used" warning at compile-time and get a run-time check failure at the point of access when debugging. However, if you access an uninitialized struct's member variable through one of its functions, you don't get any warnings or assertions. Obviously the easiest solution is don't do that, but nobody's perfect. For example: struct Test { float GetMember() const { return member; } float member; }; Test test; float f1 = test.member; // Raises warning, asserts in VS debugger at runtime float f2 = test.GetMember(); // No problem, just keeps on going This surprised me, but it makes some sense -- the compiler can't assume calling a function on an unused struct is an error, or how else would you initialize or construct it? And anything fancier just quickly brings up so many other complications that it makes sense that it wouldn't bother classifying which functions are ok to call and when, especially just as a debugging help. I know I can set up my own assertions or error checking within the class itself, but that can complicate some simpler structs. Still, it would seem like within the context of the function call, wouldn't it know insides GetMember() that member wasn't initialized yet? I'm assuming it's not only relying on static compile-time deduction, given the Run-Time Check Failure #3 it raises during execution, so based on my current understanding of it it would seem reasonable for the same checks to apply. Is this just a limitation of this specific compiler/debugger (Visual Studio 2008), or more tied to how C++ works?

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  • jQuery image hover color overlay

    - by Ryan Max
    I can't seem to find any examples of this having been done anywhere on the internet before but here is what I am going to attempt to do...I'm trying to go about the cleanest possible way of laying this out. So I have an image gallery where the images are all different sizes. I want to make it so that when you mouseover the image, it turns a shade of orange. Just a simple hover effect. I want to do this without using an image swap, otherwise I'd have to create an orange colored hover-image for each individual gallery image, I'd like this to be a bit more dynamic. My plan is just to position an empty div over the image absolutely with a background color, width and height 100% and opacity: 0. Then using jquery, on mouseover I'd have the opacity fade to 0.3 or so, and fade back to zero on mouseout. My question is, what would be the best way to layout the html and css to do this efficiently and cleanly. Here's a brief, but incomplete setup: <li> <a href="#"> <div class="hover">&nbsp;</div> <img src="images/galerry_image.png" /> </a> </li> .hover { width: 100%; height: 100%; background: orange; opacity: 0; }

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  • PySide Qt script doesn't launch from Spyder but works from shell

    - by Maxim Zaslavsky
    I have a weird bug in my project that uses PySide for its Qt GUI, and in response I'm trying to test with simpler code that sets up the environment. Here is the code I am testing with: http://stackoverflow.com/a/6906552/130164 When I launch that from my shell (python test.py), it works perfectly. However, when I run that script in Spyder, I get the following error: Traceback (most recent call last): File "/home/test/Desktop/test/test.py", line 31, in <module> app = QtGui.QApplication(sys.argv) RuntimeError: A QApplication instance already exists. If it helps, I also get the following warning: /usr/lib/pymodules/python2.6/matplotlib/__init__.py:835: UserWarning: This call to matplotlib.use() has no effect because the the backend has already been chosen; matplotlib.use() must be called *before* pylab, matplotlib.pyplot, or matplotlib.backends is imported for the first time. Why does that code work when launched from my shell but not from Spyder? Update: Mata answered that the problem happens because Spyder uses Qt, which makes sense. For now, I've set up execution in Spyder using the "Execute in an external system terminal" option, which doesn't cause errors but doesn't allow debugging, either. Does Spyder have any built-in workarounds to this?

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  • 1k of Program Space, 64 bytes of RAM. Is 1 wire communication possible?

    - by Earlz
    (If your lazy see bottom for TL;DR) Hello, I am planning to build a new (prototype) project dealing with physical computing. Basically, I have wires. These wires all need to have their voltage read at the same time. More than a few hundred microseconds difference between the readings of each wire will completely screw it up. The Arduino takes about 114 microseconds. So the most I could read is 2 or 3 wires before the latency would skew the accuracy of the readings. So my plan is to have an Arduino as the "master" of an array of ATTinys. The arduino is pretty cramped for space, but it's a massive playground compared to the tinys. An ATTiny13A has 1k of flash ROM(program space), 64 bytes of RAM, and 64 bytes of (not-durable and slow) EEPROM. (I'm choosing this for price as well as size) The ATTinys in my system will not do much. Basically, all they will do is wait for a signal from the Master, and then read the voltage of 1 or 2 wires and store it in RAM(or possibly EEPROM if it's that cramped). And then send it to the Master using only 1 wire for data.(no room for more than that!). So far then, all I should have to do is implement trivial voltage reading code (using built in ADC). But this communication bit I'm worried about. Do you think a communication protocol(using just 1 wire!) could even be implemented in such constraints? TL;DR: In less than 1k of program space and 64 bytes of RAM(and 64 bytes of EEPROM) do you think it is possible to implement a 1 wire communication protocol? Would I need to drop to assembly to make it fit? I know that currently my Arduino programs linking to the Wiring library are over 8k, so I'm a bit concerned.

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  • Parse JSON into a ListView friendly output

    - by Thomas McDonald
    So I have this JSON, which then my activity retrieves to a string: {"popular": {"authors_last_month": [ { "url":"http://activeden.net/user/OXYLUS", "item":"OXYLUS", "sales":"1148", "image":"http://s3.envato.com/files/15599.jpg" }, { "url":"http://activeden.net/user/digitalscience", "item":"digitalscience", "sales":"681", "image":"http://s3.envato.com/files/232005.jpg" } { ... } ], "items_last_week": [ { "cost":"4.00", "thumbnail":"http://s3.envato.com/files/227943.jpg", "url":"http://activeden.net/item/christmas-decoration-balls/75682", "sales":"43", "item":"Christmas Decoration Balls", "rating":"3", "id":"75682" }, { "cost":"30.00", "thumbnail":"http://s3.envato.com/files/226221.jpg", "url":"http://activeden.net/item/xml-flip-book-as3/63869", "sales":"27", "item":"XML Flip Book / AS3", "rating":"5", "id":"63869" }, { ... }], "items_last_three_months": [ { "cost":"5.00", "thumbnail":"http://s3.envato.com/files/195638.jpg", "url":"http://activeden.net/item/image-logo-shiner-effect/55085", "sales":"641", "item":"image logo shiner effect", "rating":"5", "id":"55085" }, { "cost":"15.00", "thumbnail":"http://s3.envato.com/files/180749.png", "url":"http://activeden.net/item/banner-rotator-with-auto-delay-time/22243", "sales":"533", "item":"BANNER ROTATOR with Auto Delay Time", "rating":"5", "id":"22243"}, { ... }] } } It can be accessed here as well, although it because it's quite a long string, I've trimmed the above down to display what is needed. Basically, I want to be able to access the items from "items_last_week" and create a list of them - originally my plan was to have the 'thumbnail' on the left with the 'item' next to it, but from playing around with the SDK today it appears too difficult or impossible to achieve this, so I would be more than happy with just having the 'item' data from 'items_last_week' in the list. Coming from php I'm struggling to use any of the JSON libraries which are available to Java, as it appears to be much more than a line of code which I will need to deserialize (I think that's the right word) the JSON, and they all appear to require some form of additional class, apart from the JSONArray/JSONObject script I have which doesn't like the fact that items_last_week is nested (again, I think that's the JSON terminology) and takes an awful long time to run on the Android emulator. So, in effect, I need a (preferably simple) way to pass the items_last_week data to a ListView. I understand I will need a custom adapter which I can probably get my head around but I cannot understand, no matter how much of the day I've just spent trying to figure it out, how to access certain parts of a JSON string..

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  • SQL Server search filter and order by performance issues

    - by John Leidegren
    We have a table value function that returns a list of people you may access, and we have a relation between a search and a person called search result. What we want to do is that wan't to select all people from the search and present them. The query looks like this SELECT qm.PersonID, p.FullName FROM QueryMembership qm INNER JOIN dbo.GetPersonAccess(1) ON GetPersonAccess.PersonID = qm.PersonID INNER JOIN Person p ON p.PersonID = qm.PersonID WHERE qm.QueryID = 1234 There are only 25 rows with QueryID=1234 but there are almost 5 million rows total in the QueryMembership table. The person table has about 40K people in it. QueryID is not a PK, but it is an index. The query plan tells me 97% of the total cost is spent doing "Key Lookup" witht the seek predicate. QueryMembershipID = Scalar Operator (QueryMembership.QueryMembershipID as QM.QueryMembershipID) Why is the PK in there when it's not used in the query at all? and why is it taking so long time? The number of people total 25, with the index, this should be a table scan for all the QueryMembership rows that have QueryID=1234 and then a JOIN on the 25 people that exists in the table value function. Which btw only have to be evaluated once and completes in less than 1 second.

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  • Password hashing, salt and storage of hashed values

    - by Jonathan Leffler
    Suppose you were at liberty to decide how hashed passwords were to be stored in a DBMS. Are there obvious weaknesses in a scheme like this one? To create the hash value stored in the DBMS, take: A value that is unique to the DBMS server instance as part of the salt, And the username as a second part of the salt, And create the concatenation of the salt with the actual password, And hash the whole string using the SHA-256 algorithm, And store the result in the DBMS. This would mean that anyone wanting to come up with a collision should have to do the work separately for each user name and each DBMS server instance separately. I'd plan to keep the actual hash mechanism somewhat flexible to allow for the use of the new NIST standard hash algorithm (SHA-3) that is still being worked on. The 'value that is unique to the DBMS server instance' need not be secret - though it wouldn't be divulged casually. The intention is to ensure that if someone uses the same password in different DBMS server instances, the recorded hashes would be different. Likewise, the user name would not be secret - just the password proper. Would there be any advantage to having the password first and the user name and 'unique value' second, or any other permutation of the three sources of data? Or what about interleaving the strings? Do I need to add (and record) a random salt value (per password) as well as the information above? (Advantage: the user can re-use a password and still, probably, get a different hash recorded in the database. Disadvantage: the salt has to be recorded. I suspect the advantage considerably outweighs the disadvantage.) There are quite a lot of related SO questions - this list is unlikely to be comprehensive: Encrypting/Hashing plain text passwords in database Secure hash and salt for PHP passwords The necessity of hiding the salt for a hash Clients-side MD5 hash with time salt Simple password encryption Salt generation and Open Source software I think that the answers to these questions support my algorithm (though if you simply use a random salt, then the 'unique value per server' and username components are less important).

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  • How to increase the performance of a loop which runs for every 'n' minutes.

    - by GustlyWind
    Hi Giving small background to my requirement and what i had accomplished so far: There are 18 Scheduler tasks run at regular intervals (least being 30 mins) takes input of nearly 5000 eligible employees run into a static method for iteration and generates a mail content for that employee and mails. An average task takes about 9 min multiplied by 18 will be roughly 162 mins meanwhile there would be next tasks which will be in queue (I assume). So my plan is something like the below loop try { // Handle Arraylist of alerts eligible employees Iterator employee = empIDs.iterator(); while (employee.hasNext()) { ScheduledImplementation.getInstance().sendAlertInfoToEmpForGivenAlertType((Long)employee.next(), configType,schedType); } } catch (Exception vEx) { _log.error("Exception Caught During sending " + configType + " messages:" + configType, vEx); } Since I know how many employees would come to my method I will divide the while loop into two and perform simultaneous operations on two or three employees at a time. Is this possible. Or is there any other ways I can improve the performance. Some of the things I had implemented so far 1.Wherever possible made methods static and variables too Didn't bother to catch exceptions and send back because these are background tasks. (And I assume this improves performance) Get the DB values in one query instead of multiple hits. If am successful in optimizing the while loop I think i can save couple of mins. Thanks

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  • What should a self-taught programmer with no degree learn/read?

    - by sjbotha
    I am a self-taught programmer and I do do not have any degrees. I started pretty young and I've got about 7 years of actual programming work experience. I believe I'm a pretty good programmer, but I admit that I have not played much with algorithms or delved into any really low-level aspects of programming such as how compilers work. I have worked with other programmers with and without degrees. Some were good and some not; having a degree didn't seem to make any difference as to which pot they fell into. Since then I've come to realize that it does depend on the school where the degree is obtained. Some people suggest that you really should get a degree; that there are things you'll learn in the process that you won't learn in the real world. Of course there is personal growth and discipline learned from completing a task of that magnitude, but let's just concentrate on the technical knowledge. What would I have been taught in a GOOD CS course that would aid me today and what can I read to fill the gap? I've heard the book "Algorithms" mentioned and I plan on reading that. What other books would you recommend? Edit: Clarification on 'actual work experience': Have worked for 2 small companies on teams with fewer than 5 people. About 2 years experience with Perl, Python, PHP, C, C++. About 5 years experience in Java, Applets, RMI, T-SQL, PL/SQL, VB6. 7 years experience in HTML, Javascript, bash, SQL. Most recently in Java designed and helped build an N-tier Java app with web frontend and RMI.

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  • How can I provide users with the functionality of the DBUnit DatabaseOperation methods from a web in

    - by reckoner
    I am currently updating a java-based web application which allows database developers to create stored procedure regression test suites for database testing. Currently, for test setup, execution and clean-up stages, the user is provided with text boxes where they are able to enter SQL code which is executed by the isql command. I would like to extend the application to use DB Unit’s DatabaseOperation methods to provide more ways to setup the state of the database than just SQL statements. The main reason for using Db Unit rather than just SQL statements is to be able to create and store xml and xls DataSets on a server where they can be associated with their test cases and used for data setup. My question is: How can I provide users with the functionality of the DBUnit DatabaseOperation methods from a web interface? I have considered: Creating a simple programming language and a parser to read some simple syntax involving the DB Unit method names which accept a parameter being the file location to an xml or xls DataSet. I was thinking of allowing the user to register the files they need with the web app which would catalogue them and provide each file with an identifier which could passed as a parameter to the methods in this simple programming language. Creating an XML DTD which provides the user with the ability to specify operations and parameters. If I went this approach, how can I execute the methods and their parameters that I parse from the XML document? Creating a table in the database which stores the method and a FK relation to a catalogued DataSet file, however I don’t think this would be good solution due to the fact that data entry would be tedious. Thanks for your help.

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  • uiview's controls unresponsive.. or how to foul up a view hierarchy

    - by user293139
    Hello all, I'm working on an app that has two sections, a config section and a results section. My config section needs to be 2 separate views (horizontal and vert, and yes, I can hear the intake of breath from here), with one rotatable view for the results. b/c of layout restraints and a lot of pain around rotation, I'm not using a navigation controller. I've been experiencing the joys of rotation experimentation and have settled upon keeping my views contained as subviews of my view controller. i.e. view controller.view.subviews = configH, configV, and results. I then use the controller.view bringSubviewToFront to bring the either the configH, configV, or the result view to the front. Rotation works-queue(humor intended) the angelic choirs... almost. What's happening is that my configV button's are responsive, but when the device (or simulator) is rotated, my configH controls are not. (configV is the second subview added, but the first one to be brought to the front because app comes up in portrait mode) The controls on the results view also work. Plan B was to assign the controller.view to configH, configV, or results. All of my controls now work, but rotation is now fouled up. Question 1: Is there a better way to do this? (a horizontal and vertical config view and a rotatable results view) Question 2: Does the above suggest a design issue, or is it more likely that my addled brain is just missing something in my own code. (nothing from the peanut gallery please) many thanks!

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  • How can I automatically elevate a COM interface used for automation?

    - by Jim Flood
    I have a Windows service built with ATL to expose a LocalServer32 COM interface for a set of admin commands used for configuring the service, and these can be used from VBScript for example: Set myObj = WScript.CreateObject("MySvc.Administrator") myObj.DoSomething() I want DoSomething to run elevated, and I would like the UAC prompt to come up automatically when this is called by the VBScript. Is this possible? I know I can run the script in an elevated command shell, and that I can use objShell.ShellExecute WScript.FullName, Chr(34) & WScript.ScriptFullName & Chr(34), vbNullString, "runas" for example, to run the VBScript itself elevated, and either of those work fine -- the COM method finds itself elevated. However, AFAIK getting an elevated Explorer window on the desktop is convoluted (it's not as simple as right-clicking Start/Accessories/Windows Explorer/Run as Administrator, which doesn't actually elevate.) I want a user in the local admin group to be able to drag-and-drop files and folders onto the script, and then have the script call the admin COM interface with those pathnames as arguments. (And I am hoping for something simpler than monkeying around with the args and using ShellExecute "runas".) I've tried setting UAC Execution Level to requireAdministrator in the service EXE's manifest, and setting Elevated/Enabled = 1 and LocalizedString in the registry for the MySvc.Administrator class, and these don't do the trick.

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