Search Results

Search found 5612 results on 225 pages for 'communication protocol'.

Page 193/225 | < Previous Page | 189 190 191 192 193 194 195 196 197 198 199 200  | Next Page >

• How to write a generic USB Host Driver for Printers from various vendors?

  - by Ullas

  I want to develop a USB host on an embedded device that will talk to printers from various vendors. Drivers for the vendor specific printers would be available on PC which is ultimately communicating with printer but my device is facilitating this communication and needs to perform the basic handshaking/setup of the printer (i.e, it needs to know when the printer is connected, what are the socket IDs that needs to be opened for CTRL and DATA transmissions etc). All of these printers are supposed to comply with IEEE 1284.4 standards but I see that many of them vary quiet a bit. One approach I have is to take the USB traces of handshaking from each of these printers and write various sections of code respectively (I know, that sounds ridiculous!). Is there a generic way to do this? Is there any available forum where these standard informations are mentioned? For eg: EPSON uses 'EPSON-CTRL' and 'EPSON-DATA' for its control and data services which needs to be provided to get the socket ID for these services. I am pretty sure HPs, Canon's etc would have their own service names as well. As per the standards, this was supposed to be captured in IANA but I dont see anything there. Any help on this would be greatly appreciated. Thanks and regards, Ullas

  Read the article

• Response time increasing (worsening) over time with consistent load

  - by NJ

  Ok. I know I don't have a lot of information. That is, essentially, the reason for my question. I am building a game using Flash/Flex and Rails on the back-end. Communication between the two is via WebORB. Here is what is happening. When I start the client an operation calls the server every 60 seconds (not much, right?) which results in two database SELECTS and an UPDATE and a resulting response to the client. This repeats every 60 seconds. I deployed a test version on heroku and NewRelic's RPM told me that response time degraded over time. One client with one task every 60 seconds. Over several hours the response time drifted from 150ms to over 900ms in response time. I have been able to reproduce this in my development environment (my Macbook Pro) so it isn't a problem on Heroku's side. I am not doing anything sophisticated (by design) in the server app. An action gets called, gets some data from the database, performs an AR update and then returns a response. No caching, etc. Any thoughts? Anyone? I'd really appreciate it.

  Read the article

• My iPhone app ran fine in simulator but crashed in device (iPod touch 3.1.2) test, I got the followi

  - by Mickey Shine

  I was running myapp on an iPod touch and I noticed it missed some libraries. Is that the reason? [Session started at 2010-03-19 15:57:04 +0800.] GNU gdb 6.3.50-20050815 (Apple version gdb-1128) (Fri Dec 18 10:08:53 UTC 2009) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "--host=i386-apple-darwin --target=arm-apple-darwin".tty /dev/ttys007 Loading program into debugger… Program loaded. target remote-mobile /tmp/.XcodeGDBRemote-237-78 Switching to remote-macosx protocol mem 0x1000 0x3fffffff cache mem 0x40000000 0xffffffff none mem 0x00000000 0x0fff none run Running… [Switching to thread 11779] [Switching to thread 11779] sharedlibrary apply-load-rules all (gdb) continue warning: Unable to read symbols for "/Library/MobileSubstrate/MobileSubstrate.dylib" (file not found). 2010-03-19 15:57:18.892 myapp[2338:207] MS:Notice: Installing: com.yourcompany.myapp [myapp] (478.52) 2010-03-19 15:57:19.145 myapp[2338:207] MS:Notice: Loading: /Library/MobileSubstrate/DynamicLibraries/Backgrounder.dylib warning: Unable to read symbols for "/Library/MobileSubstrate/DynamicLibraries/Backgrounder.dylib" (file not found). warning: Unable to read symbols for "/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.1.2.sdk/usr/lib/libsubstrate.dylib" (file not found). MS:Warning: message not found [myappAppDelegate applicationWillResignActive:] MS:Warning: message not found [myappAppDelegate applicationDidBecomeActive:] 2010-03-19 15:57:19.550 myapp[2338:207] in FirstViewController 2010-03-19 15:57:20.344 myapp[2338:207] in load table view 2010-03-19 15:57:20.478 myapp[2338:207] in loading splash view 2010-03-19 15:57:22.793 myapp[2338:207] in set interface Program received signal: “0”. warning: check_safe_call: could not restore current frame

  Read the article

• mutableCopyWithZone updating a property value.

  - by Jim

  I have a Class that I need to copy with the ability to make changes the value of a variable on both Classes. Simply put the classes need to remain clones of each other at all times. My understanding of the documentation is that I can do this using a shallow copy of the Class which has also been declared mutable. By shallow copying the pointer value for the variable will be cloned so that it is an exact match in both classes. So when I update the variable in the original the copy will be updated simultaneously. Is this right? As you can see below I have used mutableCopyWithZone in the class I want to copy. I have tried both NSCopyObject and allocWithZone methods to get this to work. Although I'm able to copy the class and it appears as intended, when updating the variable it is not changing value in the copied Class. - (id)mutableCopyWithZone:(NSZone *)zone { //ReviewViewer *copy = NSCopyObject(self, 0, zone); ReviewViewer *copy = [[[self class] allocWithZone:zone] init]; copy->infoTextViews = [infoTextViews copy]; return copy; } infoTextViews is a property declared as nonatomic, retain in the header file of the class being copied. I have also implemented the NSMutableCopying protocol accordingly. Any help would be great.

  Read the article

• Still some questions about USB

  - by b-gen-jack-o-neill

  Hi, few days ago I asked here about implementing USB. Now, If I may, would like to ask few more questions, about thing I dind´t quite understood. So, first, If I am right, Windows has device driver for USB interface, for the physical device that sends and receives communication. But what this driver offers to system (user)? I mean, USB protocol is made so its devices are adressed. So you first adress device than send message to it. But how sophisticted is the device controller (HW) and its driver? Is it so sophisticated that it is a chip you just send device adress and data, and it writes the outcomming data out and incomming data to some internal register to be read, or thru DMA directly to memory? Or, how its drivers (SW) really work? Does its driver has some advanced functions like send _data to _device? Becouse I somewhat internally hope there is a way to directly send some data thru USB, maybe by calling USB drivers itself? Is there any good article, tutorial you know about to really explain how all this logic works? Thanks.

  Read the article

• 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?

  Read the article

• Iteration through the HtmlDocument.All collection stops at the referenced stylesheet?

  - by Jonas

  Since "bug in .NET" is often not the real cause of a problem, I wonder if I'm missing something here. What I'm doing feels pretty simple. I'm iterating through the elements in a HtmlDocument called doc like this: System.Diagnostics.Debug.WriteLine("*** " + doc.Url + " ***"); foreach (HtmlElement field in doc.All) System.Diagnostics.Debug.WriteLine(string.Format("Tag = {0}, ID = {1} ", field.TagName, field.Id)); I then discovered the debug window output was this: Tag = !, ID = Tag = HTML, ID = Tag = HEAD, ID = Tag = TITLE, ID = Tag = LINK, ID = ... when the actual HTML document looks like this: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <title>Protocol</title> <link rel="Stylesheet" type="text/css" media="all" href="ProtocolStyle.css"> </head> <body onselectstart="return false"> <table> <!-- Misc. table elements and cell values --> </table> </body> </html> Commenting out the LINK tag solves the issue for me, and the document is completely parsed. The ProtocolStyle.css file exist on disk and is loaded properly, if that would matter. Is this a bug in .NET 3.5 SP1, or what? For being such a web-oriented framework, I find it hard to believe there would be such a major bug in it.

  Read the article

• Setting up GCALDaemon in Eclipse

  - by amadib

  Hello, my eventual goal is to be able to use the authentication and communication to a GMail inbox. In my attempt, I stumbled up on GCALDaemon and am trying to set it up as a project within eclipse. However, I am running into problems running the project from the included .launch files. I am receiving the following errors after running with -Dlog4j.debug on log4j: Trying to find [log4j.xml] using context classloader sun.misc.Launcher$AppClassLoader@1ba34f2. log4j: Trying to find [log4j.xml] using sun.misc.Launcher$AppClassLoader@1ba34f2 class loader. log4j: Trying to find [log4j.xml] using ClassLoader.getSystemResource(). log4j: Trying to find [log4j.properties] using context classloader sun.misc.Launcher$AppClassLoader@1ba34f2. log4j: Trying to find [log4j.properties] using sun.misc.Launcher$AppClassLoader@1ba34f2 class loader. log4j: Trying to find [log4j.properties] using ClassLoader.getSystemResource(). log4j: Could not find resource: [null]. log4j:WARN No appenders could be found for logger (org.gcaldaemon.core.Configurator). log4j:WARN Please initialize the log4j system properly. FATAL | Service terminated! Thanks.

  Read the article

• Is a web-server (e.g servlets) a good solution for an IM server?

  - by John

  I'm looking at a new app, broadly speaking an IM application with a strong client-server model - all communications go through a server so they can be logged centrally. The server will be Java in some form, clients could at this point be anything from a .NET Desktop app to Flex/Silverlight, to a simple web-interface using JS/AJAX. I had anticipated doing the server using standard J2EE so I get a thread-safe, multi-user server for 'free'... to make things simple let's say using Servlets (but in practice SpringMVC would be likely). This all seemed very neat but I'm concerned if the stateless nature of Servlets is the best approach. If my memory of servlets (been a year or two) is right, each time a client sent a HTTP request, typically a new message entered by the user, the servlet could not assume it had the user/chat in memory and might have to get it from the DB... regardless it has to look it up. Then it either has to use some PUSH system to inform other members of the chat, or cache that there are new messages, for other clients who poll the server using AJAX or similar - and when they poll it again has to lookup the chat, including new messages, and send the new data. I'm wondering if a better system would be the server is running core Java, and implements a socket-based communication with clients. This allows much more immediate data transfer and is more flexible if say the IM client included some game you could play. But then you're writing a custom server and sockets don't sound very friendly to a browser-based client on current browsers. Am I missing some big piece of the puzzle here, it kind of feels like I am? Perhaps a better way to ask the question would simply be "if the client was browser-based using HTML/JS and had to run on IE7+,FF2+ (i.e no HTML5), how would you implement the server?" edit: if you are going to suggest using XMPP, I have been trying to get my head around this in another question, so please consider if that's a more appropriate place to discuss this specifically.

  Read the article

• (Python/Pyramid) Better ways to have standard list/form editors?

  - by badcat

  I'm working on a number of Pyramid (former Pylons) projects, and often I have the need to display a list of some content (let's say user accounts, log entries or simply some other data). A user should be able to paginate through the list, click on a row and get a form where he/she can edit the contents of that row. Right now I'm always re-inventing the wheel by having Mako templates which use webhelpers for the pagination, Jquery UI for providing a dialog and I craft the editor form and AJAX requests on the client and server side by hand. As you may know, this eats up painfully much time. So what I'm wondering is: Is there a better way of providing lists, editor dialog and server/client communication about this, without having to re-invent the wheel every time? I heard Django takes off a big load of that by providing user accounts and other stuff out of the box; but in my case it's not just about user accounts, it can be any kind of data that is stored on the server-side in a SQL database, which should be able to be edited by a user. Thanks in advance!

  Read the article

• How would I construct a terminal command to download a folder with wget from a Media Temple (gs) ser

  - by racl101

  I'm trying to download a folder using wget on the Terminal (I'm usin a Mac if that matters) because my ftp client sucks and keeps timing out. It doesn't stay connected for long. So I was wondering if I could use wget to connect via ftp protocol to the server to download the directory in question. I have searched around in the internet for this and have attempted to write the command but it keeps failing. So assuming the following: ftp username is: [email protected] ftp host is: ftp.s12345.gridserver.com ftp password is: somepassword I have tried to write the command in the following ways: wget -r ftp://[email protected]:[email protected]/path/to/desired/folder/ wget -r ftp://serveradmin:[email protected]/path/to/desired/folder/ When I try the first way I get this error: Bad port number. When I try the second way I get a little further but I get this error: Resolving s12345.gridserver.com... 71.46.226.79 Connecting to s12345.gridserver.com|71.46.226.79|:21... connected. Logging in as serveradmin ... Login incorrect. What could I be doing wrong?

  Read the article

• Please suggest other ways of communicating between server & client.

  - by Geo

  I'm writing a TCP chat server ( programming language does not mather ). It's a school project for my nephew, so it won't be released, and all questions I'm asking are just for my knowledge :). . Some of the things it will support: chatting between users ( doh ), it will be multithreaded sending each other files I know I could easily get away with all the stuff above if I go with serialization, and just send objects from client to server and back. But, if I do that, it will be limited to a specific programming language ( meaning clients written in other programming languages may not be able to deserialize the objects ). What would be the way to go so that other clients written in other languages could be supported? One way to go, off the top of my head, would be to go in this direction: the server & the client communicate by sending messages & chunks ( in lieu of other names ). Here's what I mean by this: every time the client/server wants to send something ( text message or file ) it will first send a simple text message ( newline terminated ) with the number of the chunks it will send. Example: command 4,20,30,40,50 Where command would be something like instant-message or file,4 would be the number of chunks to be sent, 20 would be the size in bytes of the first chunk, 30 of the 2nd, and so forth. after the message was sent, the client/server will start sending chunks ( of sizes mentioned in the sent message ). What do you think about implementing the client/server communication this way? What better options are there?

  Read the article

• Passing HTML form data in the URL on local machine (file://)

  - by atzz

  Hi, I'm building a small HTML/JS application for primary use on local machine (i.e. everything is accessed via file:// protocol, though maybe in the future it will be hosted on a server within intranet). I'm trying to make a form with method="get" and action="target.html", in the hope that the browser will put form data in the URL (like, file://<path>/target.html?param1=aaa&param2=bbb). However, it's not happening (target.html opens fine, but no parameters is passed). What am I doing wrong? Is it possible to use forms over file:// at all? I can always build the url manually (via JS), but being lazy I'd prefer the browser do it for me. ;) Here is my sample form: <form name='config' action="test_form.html" method="get" enctype="application/x-www-form-urlencoded"> <input type="text" name="param1"> <input type="text" name="param2"> <input type="submit" value="Go"> </form>

  Read the article

• What kind of online hosting do I need for a WCF-based service?

  - by mafutrct

  First of all, I'm not sure if SO is the right place to ask. Please migrate me if needed. I would like to host a WCF-based service so it is available for everyone. While hosting it on my personal, local servers succeeded, I would prefer to move it to an external service provider for various reasons. I'll be blunt: I have no clue about hosting providers. I know there are webhosters, virtual and root servers and several other services. What I would like to know is what kind of hosting I need in my case. I understand that a root server would easily fulfill my requirements, but that is not exactly cheap. The program I'd like to run on the server requires .NET 4, preferably on a windows machine. Access to a folder in the file system is much appreciated (1 GB storage is enough by far). Communication with clients (in form of an applications written in .NET) via opening a port on the server. Traffic is low (<<1 GB/month?) There is no website. Having the provider perform updates would be nice. My understanding is that a virtual server would be a possible solution. Prices seem start at around 5€/month, which is ok for me. However, I read that for these cheap solutions RAM is severely limited (~400 MB), and I'm not confident that is enough to run windows and a .NET application.

  Read the article

• In C/C++,how to link dynamic link lib which compiled in GCC/G++ in MS VStudio?

  - by coanor

  These days, I use Flex & Bison generated some codes to develop a SQL-parser alike tools, these code can't compiled silently(may be this another topic) in VS2005,but GCC/G++ works well, then I compiled these code with mingw in dll(in windows xp), and then linked these function facades in VS2005, but it seems can't link the dll during linking. Does MS VS2005 recognize the dll which compiled using mingw on windows? Is there anything I need to do additional? For example, adding something in the include-file that declare the exported APIs? Does any one can give some advices? The condition is, as in VS2005, if you want to export some APIs, you may show a *.def file to tell nmake which API you want to export, and then you may create a(or some) *.h file to declare somthing about these APIs(adding some stdcall alike prefix as a call protocal) and some data-type definition. But with GCC/G++, you do not need to do such boring things, just use [ar], you can get these APIs, so my *.h file do not add call protocol and no *.def, just like common function declaration. After *.dll generated, add the *.h file and [mv] generated *.dll in VS2005 project directory, then set the linking *.dll in project setting. Does these steps generated my Question? BTW, I found and tested VC6-compiled dll can be linked with mingw in Windows XP, but the reverse can't work. Anyway, forgive my poor English, and thanks for your concern.

  Read the article

• How difficult is it to write our own Robots API, similar to G Wave Robots API ? Please read the deta

  - by user169650

  Consider the following entities : a) My own Wave-server b) My own Robots API c) Tomcat d) Google wave server/any other wave server Let us consider that a and d interact with one another via Google wave federation protocol. Now, I want to write my own Robots API in Java (similar to that of G Wave Robots API) using which I want to create Robots; which I want to host in entity c), which may in-turn connect to a) for listening to events and responding with operations. Let us consider that a) is already in place, i.e. implemented. Let us also consider that the Robot running on tomcat and entity a) are co-located, so that we do not need to use JSON-RPC for receiving events/sending operations; instead we can use Java interfaces. Now, my questions are : 1.How much of an effort is it to write my own Robots API to run on a tomcat container ? 2.What are the salient points to be taken care of ? Am I missing some important point here ? 3.How can I reuse some of the classes/packages/interfaces (e.g. com.google.wave.api.AbstractRobot, com.google.wave.api.event) with little/no changes at all ?

  Read the article

• Mercurial "server"

  - by user85116

  I've been using mercurial for a little while, but mainly for my own usage. Now though, I have a project I'm working on where two of us are building the same project, and we will probably be modifiying each other's files. I would like to setup a mercurial repo on a server, make that repo the "server", so my changes and the other editor's changes both push to that server (so basically the subversion / cvs model); I like mercurial though, and don't want to switch to something like subversion. Here in my own network, everything is done on linux, and my "server" has openssh installed. So pushing my changes (I work on multiple computers) from one computer to the server is just a matter of "hg push"; the protocol used is ssh for transfering the changes. The problem is that I use linux, the server will be windows (so no openssh, right?) and the other editor will be using windows too. As far as I know, the best way of working in mercurial in these types of setups is for the repo to pull changes from the source, rather then the source pushing to the "server". I'm behind several firewall's (not entirely my network) and my computer won't be visible from the server, and I'm assuming the other editor will be behind a firewall too (so we can't just start up the local mercurial http server and get the "server" computer to pull from that). What's the best way for both editors to get our changes to the server repo? (I should add that the server is a server on the internet, so just as visible as something like google.com. It's a hosted windows server, but I would probably have permission to install software if needed for this)

  Read the article

• NHibernate Native SQL multiple joins

  - by Chris

  Hi all, I"m having some problems with Nhibernate and native sql. I've got an entity with alot of collections and I am doing an SQL Fulltext search on it. So when returning 100 or so entities, I dont want all collections be lazy loaded. For this I changed my SQL query: SELECT Query.* FROM (SELECT {spr.*}, {adr.*}, {adrt.*}, {cty.*}, {com.*}, {comt.*}, spft.[Rank] AS [Rak], Row_number() OVER(ORDER BY spft.[Rank] DESC) AS rownum FROM customer spr INNER JOIN CONTAINSTABLE ( customerfulltext , computedfulltextindex , '" + parsedSearchTerm + @"' ) AS spft ON spr.customerid = spft.[Key] LEFT JOIN [Address] adr ON adr.customerid = spr.customerid INNER JOIN [AddressType] adrt ON adrt.addresstypeid = adr.addresstypeid INNER JOIN [City] cty ON cty.cityid = adr.cityid LEFT JOIN [Communication] com ON com.customerid = spr.customerid INNER JOIN [CommunicationType] comt ON comt.communicationtypeid = com.communicationtypeid) as Query ORDER BY Query.[Rank] DESC This is how I setup the query: var items = GetCurrentSession() .CreateSQLQuery(query) .AddEntity("spr", typeof(Customer)) .AddJoin("adr", "spr.addresses") .AddJoin("adrt", "adr.Type") .AddJoin("cty", "adr.City") .AddJoin("com", "spr.communicationItems") .AddJoin("comt", "com.Type") .List<Customer>(); What happens now is, that the query returns customers twice (or more), I assume this is because of the joins since for each customer address, communicationItem (e.g. phone, email), a new sql row is returned. In this case I thought I could use the DistinctRootEntityResultTransformer. var items = GetCurrentSession() .CreateSQLQuery(query) .AddEntity("spr", typeof(Customer)) .AddJoin("adr", "spr.addresses") .AddJoin("adrt", "adr.Type") .AddJoin("cty", "adr.City") .AddJoin("com", "spr.communicationItems") .AddJoin("comt", "com.Type") .SetResultTransformer(new DistinctRootEntityResultTransformer()) .List<Customer>(); Doing so an exception is thrown. This is because I try to list customers .List<Customer>() but the transformer returns only entities of the last join added. E.g. in the case above, the entity with alias "comt" is returned when doing .List() instead of .List(). If I would switch last join with the join alias "cty", then the transformer returns a list of cities only... Anyone knows how I can return a clean list of customers in this case?

  Read the article

• My iPhone app runs fine in simulator but quit in device (iPod touch 3.1.2) test, I got the following

  - by Mickey Shine

  I was running myapp on an iPod touch and I noticed it missed some libraries. Is that the reason? [Session started at 2010-03-19 15:57:04 +0800.] GNU gdb 6.3.50-20050815 (Apple version gdb-1128) (Fri Dec 18 10:08:53 UTC 2009) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "--host=i386-apple-darwin --target=arm-apple-darwin".tty /dev/ttys007 Loading program into debugger… Program loaded. target remote-mobile /tmp/.XcodeGDBRemote-237-78 Switching to remote-macosx protocol mem 0x1000 0x3fffffff cache mem 0x40000000 0xffffffff none mem 0x00000000 0x0fff none run Running… [Switching to thread 11779] [Switching to thread 11779] sharedlibrary apply-load-rules all (gdb) continue warning: Unable to read symbols for "/Library/MobileSubstrate/MobileSubstrate.dylib" (file not found). 2010-03-19 15:57:18.892 myapp[2338:207] MS:Notice: Installing: com.yourcompany.myapp [myapp] (478.52) 2010-03-19 15:57:19.145 myapp[2338:207] MS:Notice: Loading: /Library/MobileSubstrate/DynamicLibraries/Backgrounder.dylib warning: Unable to read symbols for "/Library/MobileSubstrate/DynamicLibraries/Backgrounder.dylib" (file not found). warning: Unable to read symbols for "/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.1.2.sdk/usr/lib/libsubstrate.dylib" (file not found). MS:Warning: message not found [myappAppDelegate applicationWillResignActive:] MS:Warning: message not found [myappAppDelegate applicationDidBecomeActive:] 2010-03-19 15:57:19.550 myapp[2338:207] in FirstViewController 2010-03-19 15:57:20.344 myapp[2338:207] in load table view 2010-03-19 15:57:20.478 myapp[2338:207] in loading splash view 2010-03-19 15:57:22.793 myapp[2338:207] in set interface Program received signal: “0”. warning: check_safe_call: could not restore current frame

  Read the article

• Creating a assertClass() method in JUnit

  - by Mike

  Hi, I'm creating a test platform for a protocol project based on Apache MINA. In MINA when you receive packets the messageReceived() method gets an Object. Ideally I'd like to use a JUnit method assertClass(), however it doesn't exist. I'm playing around trying to work out what is the closest I can get. I'm trying to find something similar to instanceof. Currently I have: public void assertClass(String msg, Class expected, Object given) { if(!expected.isInstance(given)) Assert.fail(msg); } To call this: assertClass("Packet type is correct", SomePacket.class, receivedPacket); This works without issue, however in experimenting and playing with this my interest was peaked by the instanceof operator. if (receivedPacket instanceof SomePacket) { .. } How is instanceof able to use SomePacket to reference the object at hand? It's not an instance of an object, its not a class, what is it?! Once establishing what type SomePacket is at that point is it possible to extend my assertClass() to not have to include the SomePacket.class argument, instead favouring SomePacket?

  Read the article

• Parallel programming, are we not learning from history again?

  - by mezmo

  I started programming because I was a hardware guy that got bored, I thought the problems being solved in the software side of things were much more interesting than those in hardware. At that time, most of the electrical buses I dealt with were serial, some moving data as fast as 1.5 megabit!! ;) Over the years these evolved into parallel buses in order to speed communication up, after all, transferring 8/16/32/64, whatever bits at a time incredibly speeds up the transfer. Well, our ability to create and detect state changes got faster and faster, to the point where we could push data so fast that interference between parallel traces or cable wires made cleaning the signal too expensive to continue, and we still got reasonable performance from serial interfaces, heck some graphics interfaces are even happening over USB for a while now. I think I'm seeing a like trend in software now, our processors were getting faster and faster, so we got good at building "serial" software. Now we've hit a speed bump in raw processor speed, so we're adding cores, or "traces" to the mix, and spending a lot of time and effort on learning how to properly use those. But I'm also seeing what I feel are advances in things like optical switching and even quantum computing that could take us far more quickly that I was expecting back to the point where "serial programming" again makes the most sense. What are your thoughts?

  Read the article

• How do I deal with different requests that map to the same response?

  - by daxim

  I'm designing a Web service. The request is idempotent, so I chose the GET method. The response is relatively expensive to calculate and not small, so I want to get caching (on the protocol level) right. (Don't worry about memoisation at my part, I have that already covered; my question here is actually also paying attention to the Web as a whole.) There's only one mandatory parameter and a number of optional parameter with default values if missing. For example, the following two map to the same representation of the response. (If this is a dumb way to go about it the interface, propose something better.) GET /service?mandatory_parameter=some_data HTTP/1.1 GET /service?mandatory_parameter=some_data;optional_parameter=default1;another_optional_parameter=default2;yet_another_optional_parameter=default3 HTTP/1.1 However, I imagine clients do not know this and would treat them separate and therefore waste cache storage. What should I do to avoid violating the golden rule of caching? Make up a canonical form, document it (e.g. all parameters are required after all and need to be sorted in a specific order) and return a client error unless the required form is met? Instead of an error, redirect permanently to the canonical form of a request? Or is it enough to not mind how the request looks like, and just respond with the same ETag for same responses?

  Read the article

• java packets byte

  - by user303289

  Guys, I am implementing a protocol in one of the wireless project. I am stucked at one point. In of the java file i am suppose to receive a packet and that packet is 12 byte packet and I have to write different functions for reading different parts of packets and convert it to diferent type. Like I want first four byte in one of the function and convert it to int, next two bytes in string. and again next two in string, last two hop in string and followed by last two int. I want follwing function to implement: // here is the interface /* FloodingData should use methods defined in this class. */ class FloodingPacket{ public static void main(String arg[]){ byte FloodingPack[]; // just for example to test in code FloodingPack=new byte[12]; interface IFloodingPacket { // Returns the unique sequence number for the packet int getSequenceNumber() ; // Returns the source address for the packet String getSourceAddress(); // Returns the destination address for the packet String getDestinationAddress(); // Returns the last hop address for the packet String getLastHopAddress(); // Sets the last hop address to the address of the node // which the packet was received from void updateLastHopAddress(); // Returns the entire packet in bytes (for sending) byte[] getBytes(); // Sets the bytes of the packet (for receiving) void setBytes(byte[] packet); }

  Read the article

• C# Reflection StackTrack get value

  - by John

  I'm making pretty heavy use of reflection in my current project to greatly simplify communication between my controllers and the wcf services. What I want to do now is to obtain a value from the Session within an object that has no direct access to HttpSessionStateBase (IE: Not a controller). For example, a ViewModel. I could pass it in or pass a reference to it etc. but that is not optimal in my situation. Since everything comes from a Controller at some point in my scenario I can do the following to walk the sack to the controller where the call originated, pretty simple stuff: var trace = new System.Diagnostics.StackTrace(); foreach (var frame in trace.GetFrames()) { var type = frame.GetMethod().DeclaringType; var prop = type.GetProperty("Session"); if(prop != null) { // not sure about this part... var value = prop.GetValue(type, null); break; } } The trouble here is that I can't seem to work out how to get the "instance" of the controller or the Session property so that I can read from it.

  Read the article

• Android - How to decide wether to run a Service in a separate Process?

  - by pableu

  I am working on an Android application that collects sensor data over the course of multiple hours. For that, we have a Service that collects the Sensor Data (e.g. Acceleration, GPS, ..), does some processing and stores them remotely on a server. Currently, this Service runs in a separate process (using android:service=":background" in the manifest). This complicates the communication between the Activities and the Service, but my predecessors created the Application this way because they thought that separating the Service from the Activities would make it more stable. I would like some more factual reasons for the effort of running a separate process. What are the advantages? Does it really run more stable? Is the Service less likely to be killed by the OS (to free up resources) if it's in a separate process? Our Application uses startForeground() and friends to minimize the chance of getting killed by the OS. The Android docs are not very specific about this, the mostly state that it depends on the Application's purpose ;-) TL;DR What are objective reasons to put a long-running Service in a separate process (in Android)?

  Read the article

< Previous Page | 189 190 191 192 193 194 195 196 197 198 199 200  | Next Page >