Search Results

Search found 12768 results on 511 pages for 'little snitch'.

Page 405/511 | < Previous Page | 401 402 403 404 405 406 407 408 409 410 411 412  | Next Page >

• Way to store a large dictionary with low memory footprint + fast lookups (on Android)

  - by BobbyJim

  I'm developing an android word game app that needs a large (~250,000 word dictionary) available. I need: reasonably fast look ups e.g. constant time preferable, need to do maybe 200 lookups a second on occasion to solve a word puzzle and maybe 20 lookups within 0.2 second more often to check words the user just spelled. EDIT: Lookups are typically asking "Is in the dictionary?". I'd like to support up to two wildcards in the word as well, but this is easy enough by just generating all possible letters the wildcards could have been and checking the generated words (i.e. 26 * 26 lookups for a word with two wildcards). as it's a mobile app, using as little memory as possible and requiring only a small initial download for the dictionary data is top priority. My first naive attempts used Java's HashMap class, which caused an out of memory exception. I've looked into using the SQL lite databases available on android, but this seems like overkill. What's a good way to do what I need?

  Read the article

• Implementing a c/c++ style union as a column in MySQL

  - by user81338

  Friends, I have a strange need and cannot think my way through the problem. The great and mighty Google is of little help due to keyword recycling (as you'll see). Can you help? What I want to do is store data of multiple types in a single column in MySQL. This is the database equivalent to a C union (and if you search for MySQL and Union, you obviously get a whole bunch of stuff on the UNION keyword in SQL). [Contrived and simplified case follows] So, let us say that we have people - who have names - and STORMTROOPERS - who have TK numbers. You cannot have BOTH a NAME and a TK number. You're either BOB SMITH -or- TK409. In C I could express this as a union, like so: union { char * name; int tkNo; } EmperialPersonnelRecord; This makes it so that I am either storing a pointer to a char array or an ID in the type EmperialPersonnelRecord, but not both. I am looking for a MySQL equivalent on a column. My column would store either an int, double, or varchar(255) (or whatever combination). But would only take up the space of the largest element. Is this possible? (of course anything is possible given enough time, money and will - I mean is it possible if I am poor, lazy and on a deadline... aka "out of the box")

  Read the article

• [C#] Two System.Drawing methods manifest slow drawing or flickery: Solutions? or Other Options?

  - by Luke Mcneice

  Hi all, I am doing a little graphing via the System.Drawing and im having a few problems. I'm holding data in a Queue and i'm drawing(graphing) out that data onto three picture boxes this method fills the picture box then scrolls the graph across. so not to draw on top of the previous drawings (and graduly looking messier) i found 2 solutions to draw the graph. Call plot.Clear(BACKGOUNDCOLOR) before the draw loop [block commented] although this causes a flicker to appear from the time it takes to do the actual drawing loop. call plot.DrawLine(channelPen[5], j, 140, j, 0); just before each drawline [commented] although this causes the drawing to start ok then slow down very quickly to a crawl as if a wait command had been placed before the draw command. Here is the Code for reference: /*plotx.Clear(BACKGOUNDCOLOR) ploty.Clear(BACKGOUNDCOLOR) plotz.Clear(BACKGOUNDCOLOR)*/ for (int j = 1; j < 599; j++) { if (j > RealTimeBuffer.Count - 1) break; QueueEntity past = RealTimeBuffer.ElementAt(j - 1); QueueEntity current = RealTimeBuffer.ElementAt(j); if (j == 1) { //plotx.DrawLine(channelPen[5], 0, 140, 0, 0); //ploty.DrawLine(channelPen[5], 0, 140, 0, 0); //plotz.DrawLine(channelPen[5], 0, 140, 0, 0); } //plotx.DrawLine(channelPen[5], j, 140, j, 0); plotx.DrawLine(channelPen[0], j - 1, (((past.accdata.X - 0x7FFF) / 256) + 64), j, (((current.accdata.X - 0x7FFF) / 256) + 64)); //ploty.DrawLine(channelPen[5], j, 140, j, 0); ploty.DrawLine(channelPen[1], j - 1, (((past.accdata.Y - 0x7FFF) / 256) + 64), j, (((current.accdata.Y - 0x7FFF) / 256) + 64)); //plotz.DrawLine(markerPen, j, 140, j, 0); plotz.DrawLine(channelPen[2], j - 1, (((past.accdata.Z - 0x7FFF) / 256) + 94), j, (((current.accdata.Z - 0x7FFF) / 256) + 94)); } Is there any tricks to avoid these overheads? If not would there be any other/better solutions?

  Read the article

• Java if statement strings and more

  - by user1820578

  I have decided to try and learn a little in java tonight and i have just been trying some stuff with things i have learned. My question is in an if statement how to i make two stings to be true. Here is what i have so far. if ("male".equals(gender)) && ("brendan".equals(name)) the problem i am pretty sure is the && but i am not sure. also my other question is with gender it should either be male or female. I want to have if statement with male and another for female. For this do i just do another if. For eg if ("male".equals(gender)) && ("brendan".equals(name)) { System.out.println("blah blah"); } else { System.out.println(" wrong wrong"); } if ("female".equals(gender)) { System.out.println("blah blah2"); } else { System.out.println(" wrong wrong 2"); } hope that makes sense. Any help would be great.

  Read the article

• Why does Android allocate more memory than needed when loading images

  - by Simon

  Folks, I don't think that this is a duplicate and is NOT one of those how do I avoid OOMs questions. This is a genuine quest for knowledge so hold off on those down votes please... Imagine I have a JPEG of 500x500 pixels. I load it as ARGB_8888 which is as "bad as it gets". I would expect Android to allocate 500x500x4 bytes = a little under 1MB however, look at a heap dump and you will see that Android allocates significantly more, often factors of 5-10 times greater. You frequently see questions on here about OOMS where the stack trace shows a heap request of say 15MB and it is ALWAYS much larger than is required simply to hold the bytes of the image. The OP usually catches some downvotes then is bombarded with stock answers and comments about using less memory (thanks Romain!) and in scaling. I think there is more than meets the eye here. Anybody know why this is? If there is no apparent answer, I will put together an SSCCE if it helps. PS. I assume that JPEG vs PNG etc is irrelevant since we're talking about the memory usage of the backing bitmap which is simply x times y times BPP - or am I being slow?

  Read the article

• Sqlite iPhone data insertion problem

  - by Asad Khan

  Hi I have a function which basically tries to insert some data returned from a REST call. - (void)syncLocalDatabase{ NSString *file = [[NSBundle mainBundle] pathForResource:@"pickuplines" ofType:@"db"]; NSMutableString *query = [[NSMutableString alloc] initWithFormat:@""]; sqlite3 *database = NULL; char *errorMsg = NULL; if (sqlite3_open([file UTF8String], &database) == SQLITE_OK) { for(PickUpLine *pickupline in pickUpLines){ [query appendFormat:@"INSERT INTO pickuplines VALUES(%d,%d,%d,'%@','YES')", pickupline.line_id, pickupline.thumbsUps, pickupline.thumbsDowns, [pickupline.line stringByReplacingOccurrencesOfString:@"'" withString:@"`"]]; NSLog(query); int result = sqlite3_exec(database, [query UTF8String], NULL, NULL, &errorMsg); if (result!=SQLITE_OK) { printf("\n%s",errorMsg); sqlite3_free(errorMsg); } //sqlite3_step([query UTF8String]); [query setString:@""]; }//end for }//end if [query release]; sqlite3_close(database); } everything seems fine query string in log statement is also fine but the data does not gets inserted. Where as a counterpart of this function for select statement works well. Here is the counter part - (void)loadLinesFromDatabase{ NSString *file = [[NSBundle mainBundle] pathForResource:@"pickuplines" ofType:@"db"]; sqlite3 *database = NULL; if (sqlite3_open([file UTF8String], &database) == SQLITE_OK) { sqlite3_exec(database, "SELECT * FROM pickuplines", MyCallback, linesFromDatabase, NULL); } sqlite3_close(database); } I have implemented callback & it works fine. I am a little new to Sqlite can someone please point out what am I doing wrong. Thanx

  Read the article

• What's the best way of accessing a DRb object (e.g. Ruby Queue) from Scala (and Java)?

  - by Tom Morris

  I have built a variety of little scripts using Ruby's very simple Queue class, and share the Queue between Ruby and JRuby processes using DRb. It would be nice to be able to access these from Scala (and maybe Java) using JRuby. I've put together something Scala and the JSR-223 interface to access jruby-complete.jar. import javax.script._ class DRbQueue(host: String, port: Int) { private var engine = DRbQueue.factory.getEngineByName("jruby") private var invoker = engine.asInstanceOf[Invocable] engine.eval("require \"drb\" ") private var queue = engine.eval("DRbObject.new(nil, \"druby://" + host + ":" + port.toString + "\")") def isEmpty(): Boolean = invoker.invokeMethod(this.queue, "empty?").asInstanceOf[Boolean] def size(): Long = invoker.invokeMethod(this.queue, "length").asInstanceOf[Long] def threadsWaiting: Long = invoker.invokeMethod(this.queue, "num_waiting").asInstanceOf[Long] def offer(obj: Any) = invoker.invokeMethod(this.queue, "push", obj.asInstanceOf[java.lang.Object]) def poll(): Any = invoker.invokeMethod(this.queue, "pop") def clear(): Unit = { invoker.invokeMethod(this.queue, "clear") } } object DRbQueue { var factory = new ScriptEngineManager() } (It conforms roughly to java.util.Queue interface, but I haven't declared the interface because it doesn't implement the element and peek methods because the Ruby class doesn't offer them.) The problem with this is the type conversion. JRuby is fine with Scala's Strings - because they are Java strings. But if I give it a Scala Int or Long, or one of the other Scala types (List, Set, RichString, Array, Symbol) or some other custom type. This seems unnecessarily hacky: surely there has got to be a better way of doing RMI/DRb interop without having to use JSR-223 API. I could either make it so that the offer method serializes the object to, say, a JSON string and takes a structural type of only objects that have a toJson method. I could then write a Ruby wrapper class (or just monkeypatch Queue) to would parse the JSON. Is there any point in carrying on with trying to access DRb from Java/Scala? Might it just be easier to install a real message queue? (If so, any suggestions for a lightweight JVM-based MQ?)

  Read the article

• Technique for selectively formatting data in a PowerShell pipeline and output as HTML

  - by halr9000

  Say that you want to do some fancy formatting of some tabular output from powershell, and the destination is to be html (either for a webserver, or to be sent in an email). Let's say for example that you want certain numeric values to have a different background color. Whatever. I can think of two solid programmatic ways to accomplish this: output XML and transform with XSLT, or output HTML and decorate with CSS. XSLT is probably the harder of the two (I say that because I don't know it), but from what little I recall, it has the benefit of bring able to embed the selection criteria (xpath?) for aforementioned fancy formatting. CSS on the other hand needs a helping hand. If you wanted a certain cell to be treated specially, then you would need to distinguish it from its siblings with a class, id, or something along those lines. PowerShell doesn't really have a way to do that natively, so that would mean parsing the HTML as it leaves convertto-html and adding, for example, a "emphasis" class: <td class="emphasis">32MB</td> I don't like the idea of the required text parsing, especially given that I would rather be able to somehow emphasize what needs emphasizing in Powershell before it hits HTML. Is XSLT the best way? Have suggestions for how to markup the HTML after it leaves convertto-html or ideas of a different way?

  Read the article

• How do I use a jQuery not selector to select relative URLs?

  - by Matt

  I'm working on a little jQuery script to add Google Analytics pageTracker onclick data to all relative URLs on my forum, allowing me to track clicks to external sites. I don't want to add the onclick to internal links on forum.sitename or sitename, and I don't want to add them to any hrefs marked # or that start with /. My script below works nicely, but for one minor problem! All of the forum's URLs are relative and don't start with /. I appear to have no way to change that, so need to modify the jQuery below to prevent it adding the onclick to links like as it currently does. What I want to do, is to write a .not() function like .not("[href!^=http") to prevent jQuery from adding the onclick to any hrefs which do not start with http. However, .not() appears not to support this. I'm new to jQuery and can't figure this out. Any pointers would be massively appreciated. $(document).ready(function(){ // Get URL from a href var URL = $("a").attr('href'); // Add pageTracker data for GA tracking $("a") .not("[href^=#]") .not("[href^=http://forum.sitename]") .not("[href^=http://www.sitename]") .attr("onclick","pageTracker._trackEvent('Outgoing_Links', 'Forum', " + URL + ");") ; }); Thanks!

  Read the article

• Preventing a heavy process from sinking in the swap file

  - by eran

  Our service tends to fall asleep during the nights on our client's server, and then have a hard time waking up. What seems to happen is that the process heap, which is sometimes several hundreds of MB, is moved to the swap file. This happens at night, when our service is not used, and others are scheduled to run (DB backups, AV scans etc). When this happens, after a few hours of inactivity the first call to the service takes up to a few minutes (consequent calls take seconds). I'm quite certain it's an issue of virtual memory management, and I really hate the idea of forcing the OS to keep our service in the physical memory. I know doing that will hurt other processes on the server, and decrease the overall server throughput. Having that said, our clients just want our app to be responsive. They don't care if nightly jobs take longer. I vaguely remember there's a way to force Windows to keep pages on the physical memory, but I really hate that idea. I'm leaning more towards some internal or external watchdog that will initiate higher-level functionalities (there is already some internal scheduler that does very little, and makes no difference). If there were a 3rd party tool that provided that kind of service is would have been just as good. I'd love to hear any comments, recommendations and common solutions to this kind of problem. The service is written in VC2005 and runs on Windows servers.

  Read the article

• Android Layout + Programming

  - by MD

  I'm trying to create a "scrollable" layout in Android. Even using developers.android.com, though, I feel a little bit lost at the moment. I'm somewhat new to Java, but not so much that I feel I should be having these issues--being new to Android is the bigger problem right now. The layout I'm trying to create should scroll in a sort of a "grid". I THINK what I'm looking for is the Gallery view, but I'm really lost as to how to implement it at the moment. I want it to "snap" to center the frame, like in the actual Gallery application. Essentially, if I had a photo gallery of 9 pictures, the idea is to scroll between them up/down AND side to side, in a 3x3 manner. Doesn't need to dynamically adjust, or anything like that, I just want a grid I can scroll through. I'm also not asking for anyone to give me explicit code for it--I'm trying to learn, more than anything. But pointing me in the right direction for helpful layout programming resources would be greatly appreciated, and confirming if it's a Gallery view I'm looking for would also be really helpful. Thanks in advance.

  Read the article

• MemoryFailPoint fires to early in WinXP 64

  - by msedi

  Hello, I have created a volume class (called VoxelVolume) with a self-organizing memory management, since the GC in C# didn't provide a good mechanism for managing contents of the volume for mapping, unmapping and remapping. Although I could have used the mechanisms of virtual memory, the problem is that the files are often too large to fit into the page file and I don't want to force the users to increase the pagefile size. Currently this system is working quite well and there is no problem in lacking resources and OutOfMemoryExceptions since the InsufficientMemoryException using the MemoryFailPoint works quite well. This was all testes on a 32bit WinXP system with 2GB of main memory. Running the same mechanism on 64bit system with 32GB of main memory also works well, but when the application runs the MemoryFailPoint suddenly throws an exception although 24GB of main memory are still free. Another point is when the MemoryFailPoint has fired once, it fires everytime and there is no chance to get rid of it. What I have read so far, that there is a small object and a large object heap (SOH and LOH). But only for the SOH the GC takes real care of and I can free the SOH from unused objects by applying GC.Collect() and GC.WaitForPendingFinalizers. The MemoryFailPoint is obviously the only way to get a little bit of control for the LOH, but since there is enough memory left on the system I see no reason why the MemoryFilePoint should fire. Is there any experience around here using the MemoryFailPoint? Thank you for your help Martin

  Read the article

• SharePoint webpart with button to auto-login to 3rd party website

  - by JCdowney

  I have been tasked with creating a SharePoint 2007 webpart that logs the user directly into our website (which uses forms authentication). Most likely the username and password will be same in the SharePoint account as in our website. Ideally we would like it to be fully integrated in that the webpart looks up the SP login & password, somehow encodes that using SHA1, MD5 or similar encryption, then passes that along to our login page on the query string. However given we have little experience with SharePoint, and that it's probably impossible to programmatically access the SP username/password from a webpart we realize this isn't very likely to be possible and if so would probably require a lot of development time. Another option would be to load a login form from the website within an iframe in the webpart, which would show the login & password first but store a "remember me" cookie after the first login, and on each subsequent load display just a button that logs them in directly using the cookie. Has anyone done something similar before? I'm in over my head, any guidance would be much appreciated! :)

  Read the article

• Entity Framework and WCf

  - by Nihilist

  Hi I am little confused on designing WCf services with EF. When using WCf and EF, where do we draw this line on what properties to return and what not to with the entity. Here is my scenario I have User. Here are the relations. User [1 to many] Address, User [ 1 to many] Email, User [ 1 to many] Phone So now on the webform, on page1 I can edit user information. say I can edit few properties on the user entity and can also edit address, phone, email entities[ like add / delete and update any] On page2, i can only update user properties and nothing related to navigation properties [ address, email, phone]. So when I return the User Entity [ OR DTO] should i be returning the navigation properties too? Or should the client make multiple calls to get navigation properites. Also, how does it go with Save? Like should the client make multiple calls to save user and related entites or just one call to save the graph? Lets say, if I just have a Save(User user) [ where user has all the related entities too] both page1 and page2 will call save and pass me the user. but one page1 i will need a lot more information. but on page2 i just need the user primitive properties. So my question is, where do we draw this line, how do we design theses services ? Is the WCF operation designed on the page and the fields it has ? I am hoping i explained my problem well enough.

  Read the article

• Static Vs Non-Static Method Performance C#

  - by dotnetguts

  Hello All, I have few global methods declared in public class in my asp.net web application. I have habbit of declaring all global methods in public class in following format public static string MethodName(parameters) { } I want to know how it would impact on performance point of view? 1) Which one is Better? Static Method or Non-Static Method? 2) Reason why it is better? Following link shows Non-Static methods are good because, static methods are using locks to be Thread-safe. The always do internally a Monitor.Enter() and Monitor.exit() to ensure Thread-safety. http://bytes.com/topic/c-sharp/answers/231701-static-vs-non-static-function-performance And Following link shows Static Methods are good static methods are normally faster to invoke on the call stack than instance methods. There are several reasons for this in the C# programming language. Instance methods actually use the 'this' instance pointer as the first parameter, so an instance method will always have that overhead. Instance methods are also implemented with the callvirt instruction in the intermediate language, which imposes a slight overhead. Please note that changing your methods to static methods is unlikely to help much on ambitious performance goals, but it can help a tiny bit and possibly lead to further reductions. http://dotnetperls.com/static-method I am little confuse which one to use? Thanks

  Read the article

• Are UTF16 (as used by for example wide-winapi functions) characters always 2 byte long?

  - by Cray

  Please clarify for me, how does UTF16 work? I am a little confused, considering these points: There is a static type in C++, WCHAR, which is 2 bytes long. (always 2 bytes long obvisouly) Most of msdn and some other documentation seem to have the assumptions that the characters are always 2 bytes long. This can just be my imagination, I can't come up with any particular examples, but it just seems that way. There are no "extra wide" functions or characters types widely used in C++ or windows, so I would assume that UTF16 is all that is ever needed. To my uncertain knowledge, unicode has a lot more characters than 65535, so they obvisouly don't have enough space in 2 bytes. UTF16 seems to be a bigger version of UTF8, and UTF8 characters can be of different lengths. So if a UTF16 character not always 2 bytes long, how long else could it be? 3 bytes? or only multiples of 2? And then for example if there is a winapi function that wants to know the size of a wide string in characters, and the string contains 2 characters which are each 4 bytes long, how is the size of that string in characters calculated? Is it 2 chars long or 4 chars long? (since it is 8 bytes long, and each WCHAR is 2 bytes)

  Read the article

• How do I toggle CSS with jQuery?

  - by marcamillion

  I have the following code: $('#bc' + $.trim($this) + ' span.dashed-circle').css({ 'border' : '5px solid #000'}); That is triggered by a click.function(). I would like that to be a toggle - so when I click the element, it changes the border to what I have above...but when it is clicked again it disappears or rather sets the border to ' '. Thoughts? Edit: I should have been explicit...but I don't want to create a CSS class. The reason being is because when I do that, it messes up the formatting of the element being styled. I am sure that it is some small quirk somewhere that would fix it, but I am not interested in wading through the entire code base to fix little positioning issues with a new class. I would much rather just edit the css attribute directly - because it doesn't interfere with the layout. Edit2: Here is the jsfiddle of the code I am trying to edit. If you notice, I have the CSS attributes last. But how do I let that be toggled ? Edit3: If anyone is interested...the UI that this will be used in is for my webapp - http://www.compversions.com

  Read the article

• Concurrent Programming:Should I write a sequential program first, then add thread safety?

  - by evthim

  I'm working on a project where we have to create a number of threads(actual number will be inputted in by testers (TA's)). I'm having trouble not only with the programming but also with the design, I can't wrap my head around all of the threads that will be invoked and where I might cause errors. The project is due soon so I don't want to waste time on this if it'll actually set me back, but I was wondering if I should write the program like only one thread will be running and everything should be sequential and then later go back and try to add the thread safety parts of the code? Would that take twice the original amount of time? Project Description: Note:I'm going to be as vague as possible so I don't violate any honor codes, sorry :( your program should accept n number of objectA threads, m number of objectB threads, and r number of objectC objectB threads interact with code in objectA. objectA threads interact with code in objectB and objectC objectB and objectC don't directly interact, but do so indirectly through objectA -ex: objectB needs something from objectA. objectA gets the result for that something by calling objectC my confusion stems mostly from the fact that all of this interactions will be done by m+n threads and there are various restrictions throughout the descriptions, like objectB can request something from objectA, and objectA has to wait for objectC to finish that something before returning it to objectB. Also each objectA thread can only work on one instruction from objectB at a time, etc. etc. I just want to know if I write the code so that there is only 1 objectA, 1 objectB and 1 object C, can I go back and easily modify it so that those 1's can be changed to m, n and r? Sorry again, if my description is a little bit confusing.

  Read the article

• php and mysql site design question

  - by Jacksta

  I am trying to build a website with mysql and php. This is the first site I have attempted so I want to write a little plan and get some feedback. The site allows users to add some text in a text field as a “comment”. Once the comment has been entered into the site it is added to the database where it can be voted for by other users. When a new comment has been added to the database it needs to create a new page, e.g. www.xxxxx.com/commentname or www.xxxxxx.com/?id=99981. There will be a list of "Comments" in the database along with the number of votes for each comment. The home page will have two functions. 1) Allow users to add a "comment" 2) Display two tables, each with 20 rows containing most "popular comments" and "recent comments" Each comment will generate its one page where the comment will be displayed. Here users can read the comment and Vote for the comment if they wish. Please help me out by explaining how to do the following. -Generate a new page whenever a comment is added to the database -Add a vote to the vote count in the comment database. -Display the top 20 most popular comments as per number of votes.

  Read the article

• Why doesn't java.lang.Number implement Comparable?

  - by Julien Chastang

  Does anyone know why java.lang.Number does not implement Comparable? This means that you cannot sort Numbers with Collections.sort which seems to me a little strange. Post discussion update: Thanks for all the helpful responses. I ended up doing some more research about this topic. The simplest explanation for why java.lang.Number does not implement Comparable is rooted in mutability concerns. For a bit of review, java.lang.Number is the abstract super-type of AtomicInteger, AtomicLong, BigDecimal, BigInteger, Byte, Double, Float, Integer, Long and Short. On that list, AtomicInteger and AtomicLong to do not implement Comparable. Digging around, I discovered that it is not a good practice to implement Comparable on mutable types because the objects can change during or after comparison rendering the result of the comparison useless. Both AtomicLong and AtomicInteger are mutable. The API designers had the forethought to not have Number implement Comparable because it would have constrained implementation of future subtypes. Indeed, AtomicLong and AtomicInteger were added in Java 1.5 long after java.lang.Number was initially implemented. Apart from mutability, there are probably other considerations here too. A compareTo implementation in Number would have to promote all numeric values to BigDecimal because it is capable of accommodating all the Number sub-types. The implication of that promotion in terms of mathematics and performance is a bit unclear to me, but my intuition finds that solution kludgy.

  Read the article

• What are some of the core principles needed to master Multi threading using Delphi?

  - by Gary Becks

  I am kind of new to programming in general (about 8 months with on and off in delphi and a little python here and there) and I am in the process of buying some books. I am interested in learning about concurrent programming and building multi threaded apps using Delphi. Whenever I do a search for "multithreading delphi" or "delphi multithreading tutorial" I seem to get conflicting results as some of the stuff is about using certain libraries (omnithread library) and other stuff seems to be more geared towards programmers with more experience. I have studied quite a few books on delphi and for the most part they seem to kind of skim the surface and not really go into depth on the subject. I have a friend who is a programmer (he uses c++) who recommends I learn what is actually going on with the underlying system when using threads as opposed to jumping into how to actually implement them in my programs first. On amazon.com there are quite a few books on concurrent programming but none of them seem to be made with Delphi in mind. Basically I need to know what are the main things I should be focused on learning before jumping into using threads, if I can/should attempt to learn them using books that are not specifically aimed at delphi developers (don't want to confuse myself reading books with a bunch of code examples in other languages right now) and if there are any reliable resources/books on the subject that anyone here could recommend. Thanks in advance.

  Read the article

• How do I serialise a graph in Java without getting StackOverflowException?

  - by Tim Cooper

  I have a graph structure in java, ("graph" as in "edges and nodes") and I'm attempting to serialise it. However, I get "StackOverflowException", despite significantly increasing the JVM stack size. I did some googling, and apparently this is a well known limitation of java serialisation: that it doesn't work for deeply nested object graphs such as long linked lists - it uses a stack record for each link in the chain, and it doesn't do anything clever such as a breadth-first traversal, and therefore you very quickly get a stack overflow. The recommended solution is to customise the serialisation code by overriding readObject() and writeObject(), however this seems a little complex to me. (It may or may not be relevant, but I'm storing a bunch of fields on each edge in the graph so I have a class JuNode which contains a member ArrayList<JuEdge> links;, i.e. there are 2 classes involved, rather than plain object references from one node to another. It shouldn't matter for the purposes of the question). My question is threefold: (a) why don't the implementors of Java rectify this limitation or are they already working on it? (I can't believe I'm the first person to ever want to serialise a graph in java) (b) is there a better way? Is there some drop-in alternative to the default serialisation classes that does it in a cleverer way? (c) if my best option is to get my hands dirty with low-level code, does someone have an example of graph serialisation java source-code that can use to learn how to do it?

  Read the article

• Why are (almost) all the on-line games written in ActionScript (Flash) not Java?

  - by MasterPeter

  I absolutely love good defender games (e.g. Gemcraft, Protector: reclaiming the throne) as they can be intellectually quite challenging; it's like playing chess but a little less thinking a bit more action. Sadly, there are not that many good ones out there and I thought I would create one myself and share it with the rest of the world by making it available on-line. I have never worked with ActionScript but when it comes to on-line games, this is the main choice. I have tried to find a decent 2D game in the form of a Java applet but to no avail. Why is this so? I could write the game, most comfortably, in Delphi for Win32 but then people would need to download the executable, which could deter some form downloading it, and also it would only work on Windows. I am also familiar with Java, having worked with Java for the last four years or so. Although I don't have much experience with games programming. Should I note be deterred by the fact that all online games are written for in Flash and create my defender game as a Java applet, or should I consider learning ActionScript and games development for the ActionScript Virtual Machine (AS3 looks very much like Java... but still, it's an entirely new technology to me and I might never use it professionally.) Could you, please, just answer the the question in the title? Why Flash, not Java applets? Is it only 'politics'?

  Read the article

• What different terms mean the same thing (or don't, but people think they do)?

  - by Matthew Jones

  One of the pitfalls I run into on a daily basis is customers saying one thing while meaning another. Usually, this is just due to a miscommunication somewhere, but occasionally they are, in fact, saying the same thing I am just using a different term. For example, one of my customers the other day mentioned a feature he called, "find as you type." Being a little confused, I asked him what he meant, and he described the feature in Google where, once you start typing a search query, Google suggests other, popular queries that match the letters you have typed. Click! He meant AutoComplete! He was not wrong, it is just that I had never heard that term before. In the spirit of reducing confusion, what terms can you think of that are different but mean, essentially, the same thing? Also, what terms do people think mean the same thing, but don't. Please differentiate between the two. Please only one set of terms per answer, so we can vote on the best ones.

  Read the article

• efficient android rendering

  - by llll

  I've read quite a few tutorials on game programming on android, and all of them provide basically the same solution as to drawing the game, that is having a dedicated thread spinning like this: public void run() { while(true) { if(!surfaceHolder.getSurface().isValid()) continue; Canvas canvas = surfaceHolder.lockCanvas(); drawGame(canvas); /* do actual drawing here */ surfaceHolder.unlockCanvasAndPost(canvas); } } now I'm wondering, isn't this wasteful? Suppose I've a game with very simple graphics, so that the actual time in drawGame is little; then I'm going to draw the same things on and on, stealing cpu from the other threads; a possibility could be skipping the drawing and sleeping a bit if the game state hasn't changed, which I could check by having the state update thread mantaining a suitable status flag. But maybe there are other options. For example, couldn'it be possible to synchronize with rendering, so that I don't post updates too often? Or am I missing something and that is precisely what lockCanvas does, that is it blocks and burns no cpu until proper time? Thanks in advance L.

  Read the article

< Previous Page | 401 402 403 404 405 406 407 408 409 410 411 412  | Next Page >