Search Results

Search found 8567 results on 343 pages for 'thread safety'.

Page 151/343 | < Previous Page | 147 148 149 150 151 152 153 154 155 156 157 158  | Next Page >

• An algorithm Problem

  - by Vignesh

  For coverage, I've a set of run time variables of from my program execution. It happens that I get it from a series of executions(Automated testing). ie. its a vector<vector<var,value>> I've a limited set of variables with expected values and generate combination s, that is I have vector<vector<var,value>(smaller than the execution vector)>. Now I need to compare and tell which of the combination I generated were exactly executed in one of the tests. My algo is O(n^4). Is there any way to bring it down. Something like set intersection. I'm using java, and vectors because of thread safety.

  Read the article

• Webapp: safetly update a shared List/Map in the AppContext

  - by al nik

  I've Lists and Maps in my WebAppContext. Most of the time these are only read by multiple Threads but sometimes there's the need to update or add some data. I'm wondering what's the best way to do this without incurring in a ConcurrentModificationException. I think that using CopyOnWriteArrayList I can achieve what I want in terms of - I do not have to sync on every read operation- I can safety update the list while other threads are reading it. Is this the best solution? What about Maps?

  Read the article

• Best data-structure to use for two ended sorted list

  - by fmark

  I need a collection data-structure that can do the following: Be sorted Allow me to quickly pop values off the front and back of the list Remain sorted after I insert a new value Allow a user-specified comparison function, as I will be storing tuples and want to sort on a particular value Thread-safety is not required Optionally allow efficient haskey() lookups (I'm happy to maintain a separate hash-table for this though) My thoughts at this stage are that I need a priority queue and a hash table, although I don't know if I can quickly pop values off both ends of a priority queue. I'm interested in performance for a moderate number of items (I would estimate less than 200,000). Another possibility is simply maintaining an OrderedDictionary and doing an insertion sort it every-time I add more data to it. Furthermore, are there any particular implementations in Python. I would really like to avoid writing this code myself.

  Read the article

• Using read() directly into a C++ std:vector

  - by Joe

  I'm wrapping up user space linux socket functionality in some C++ for an embedded system (yes, this is probably reinventing the wheel again). I want to offer a read and write implementation using a vector. Doing the write is pretty easy, I can just pass &myvec[0] and avoid unnecessary copying. I'd like to do the same and read directly into a vector, rather than reading into a char buffer then copying all that into a newly created vector. Now, I know how much data I want to read, and I can allocate appropriately (vec.reserve). I can also read into &myvec[0], though this is probably a VERY BAD IDEA. Obviously doing this doesn't allow myvec.size to return anything sensible. Is there any way of doing this that 1) Doesn't completely feel yucky from a safety/C++ perspective and 2) Doesn't involve two copies of the data block - once from kernel to user space and once from a C char * style buffer into a C++ vector. Any thoughts collective?

  Read the article

• 'Why' and 'Where' Generics is actually used?

  - by NLV

  Hi all I know that generics are used to achieve type safety and i frequently read that they are largely used in custom collections. But why actually do we need to have it generic? For example, Why cant i use string[] instead of List<string> Lets consider i declare generic class and it has a property X T x; If i provide a method for the class which does x = x + 1; what does it mean actually? I dono what T is actually going to be and i dono what x = x + 1 going to perform actually? If i'm not able to do my own manipulations in my methods how the generics are going to be help me anyway? I've already studied lot of bookish answers. It would be much appreciated if any one can provide some clear insights in this. Regards NLV

  Read the article

• Ways to improve Java Generics and dont say get rid of wildcards and reification.

  - by mP

  Sometimes i like to write up template classes and use type parameters to make the abstract methods more type safe. Template<X> { abstract void doStuff( X ); // NOT public } While type safety is great etc, the problem remains that even though X is not visible to outside code, one must still include the type to avoid warnings. My solution in this case would be to make it possible to define a scope for type parameters (now they are always public). Would other original features besides the obvious would you like.

  Read the article

• Surface Detection in 2d Game?

  - by GamiShini

  I'm working on a 2D Platform game, and I was wondering what's the best (performance-wise) way to implement Surface (Collision) Detection. So far I'm thinking of constructing a list of level objects constructed of a list of lines, and I draw tiles along the lines. ( http://img375.imageshack.us/img375/1704/lines.png ). I'm thinking every object holds the ID of the surface that he walks on, in order to easily manipulate his y position while walking up/downhill. Something like this: //Player/MovableObject class MoveLeft() { this.Position.Y = Helper.GetSurfaceById(this.SurfaceId).GetYWhenXIs(this.Position.X) } So the logic I use to detect "droping/walking on surface" is a simple point (player's lower legs)-touches-line (surface) check (with some safety approximation - let`s say 1-2 pixels over the line). Is this approach OK? I`ve been having difficulty trying to find reading material for this problem, so feel free to drop links/advice.

  Read the article

• Perfect hash in Scala.

  - by Lukasz Lew

  I have some class C: class C (...) { ... } I want to use it to index an efficient map. The most efficient map is an Array. So I add a "global" "static" counter in companion object to give each object unique id: object C { var id_counter = 0 } In primary constructor of C, with each creation of C I want to remember global counter value and increase it. Question 1: How to do it? Now I can use id in C objects as perfect hash to index array. But array does not preserve type information like map would, that a given array is indexed by C's id. Question 2: Is it possible to have it with type safety?

  Read the article

• Problem at JUnit test with generics

  - by Tom Brito

  In my utility method: public static <T> T getField(Object obj, Class c, String fieldName) { try { Field field = c.getDeclaredField(fieldName); field.setAccessible(true); return (T) field.get(obj); } catch (Exception e) { e.printStackTrace(); fail(); return null; } } The line return (T) field.get(obj); gives the warning "Type safety: Unchecked cast from Object to T"; but I cannot perform instanceof check against type parameter T, so what am I suppose to do here?

  Read the article

• Should I use C++0x Features Now?

  - by svu2g

  With the official release of VS 2010, is it safe for me to start using the partially-implemented C++0x feature set in my new code? The features that are of interest to me right now are both implemented by VC++ 2010 and recent versions of GCC. These are the only two that I have to support. In terms of the "safety" mentioned in the first sentence: can I start using these features (e.g., lambda functions) and still be guaranteed that my code will compile in 10 years on a compiler that properly conforms to C++0x when it is officially released? I guess I'm asking if there is any chance that VC++ 2010 or GCC will end up like VC++ 6; it was released before the language was officially standardized and consequently allowed grossly ill-formed code to compile. After all, Microsoft does say that "10 is the new 6". ;)

  Read the article

• Heavy use of templates for mobile platforms

  - by Chris P. Bacon

  I've been flicking through the book Modern C++ Design by Andrei Alexandrescu and it seems interesting stuff. However it makes very extensive use of templates and I would like to find out if this should be avoided if using C++ for mobile platform development (Brew MP, WebOS, iOS etc.) due to size considerations. In Symbian OS C++ the standard use of templates is discouraged, the Symbian OS itself uses them but using an idiom known as thin templates where the underlying implementation is done in a C style using void* pointers with a thin template layered on top of this to achieve type safety. The reason they use this idiom as opposed to regular use of templates is specifically to avoid code bloating. So what are opinions (or facts) on the use of templates when developing applications for mobile platforms.

  Read the article

• Help me understand Dispose() implementation code from MSDN

  - by Benny

  the following code is from MSDN: Idisposable pattern protected virtual void Dispose(bool disposing) { // If you need thread safety, use a lock around these // operations, as well as in your methods that use the resource. if (!_disposed) { if (disposing) { if (_resource != null) _resource.Dispose(); Console.WriteLine("Object disposed."); } // Indicate that the instance has been disposed. _resource = null; _disposed = true; } } why the following statement: _resource = null; _disposed = true; are not enclosed by if (disposing) statement block? for me i would probably write like this: if (disposing) { if (_resource != null) { _resource.Dispose(); _resource = null; _disposed = true; } Console.WriteLine("Object disposed."); } anything wrong with my version?

  Read the article

• Server-side application configuration security. Best practices

  - by Andrew Florko

  We publish server-side application to our customer workstation and customer's security guys are concerned about configuration connection strings safety. Connection strings are stored as plain text right now, but as configuration file is not in the public/shared folder we supposed that workstation security itself is enough. What are the ways to improve connection strings security further? It is a big step forward to encrypt password and keep a decryption key on the same workstation? What are the steps we can take to keep connection strings (and alike) information more and more securable? Thank you in advance!

  Read the article

• How long until programming becomes a professionally certified (and respected as such) skill such as

  - by Michael Campbell

  Given Toyota's recent issues and the ENORMOUS amount of safety that is being relegated to computers, how long do you think it will be before programming, or perhaps programming certain things (embedded transportation software, (air) traffic control, electrical grid, hospital equipment, nuclear plant security, planes, etc.) becomes regulated? And/or, how long before there will be certain regulated certifications before you can call yourself a "software developer", like Architects and Engineers have now? (NB: I'm from the US, so I don't know how it works in other countries; please forgive my ignornace.)

  Read the article

• Linq query joining with a subquery

  - by Alan Fisher

  I am trying to reproduce a SQL query using a LINQ to Entities query. The following SQL works fine, I just don't see how to do it in LINQ. I have tried for a few hours today but I'm just missing something. SELECT h.ReqID, rs.RoutingSection FROM ReqHeader h JOIN ReqRoutings rr ON rr.ReqRoutingID = (SELECT TOP 1 r1.ReqRoutingID FROM ReqRoutings r1 WHERE r1.ReqID = h.ReqID ORDER BY r1.ReqRoutingID desc) JOIN ReqRoutingSections rs ON rs.RoutingSectionID = rr.RoutingSectionID Edit*** Here is my table scema- Requisitions: ReqID PK string ReqDate datetime etc... ReqRoutings: ID PK int ReqID FK RoutingSection FK int RoutingDate ReqRoutingSections: Id PK int RoutingSection string The idea is that each Requisition can be routed many times, for my query I need the last RoutingSection to be returned along with the Requisition info. Sample data: Requisitions: - 1 record ReqID 123456 ReqDate '12/1/2012' ReqRoutings: -- 3 records id 1 ReqID 123456 RoutingSection 3 RoutingDate '12/2/2012' id 2 ReqID 123456 RoutingSection 2 RoutingDate '12/3/2012' id 3 ReqID 123456 RoutingSection 4 RoutingDate '12/4/2012' ReqRoutingSections: -- 3 records id 2 Supervision id 3 Safety id 4 Qaulity Control The results of the query would be ReqID = '123456' RoutingSection = 'QualityControl' -- Last RoutingSection requisition was routed to

  Read the article

• Lazy evaluation with ostream C++ operators

  - by SavinG

  I am looking for a portable way to implement lazy evaluation in C++ for logging class. Let's say that I have a simple logging function like void syslog(int priority, const char *format, ...); then in syslog() function we can do: if (priority < current_priority) return; so we never actually call the formatting function (sprintf). On the other hand, if we use logging stream like log << LOG_NOTICE << "test " << 123; all the formating is always executed, which may take a lot of time. Is there any possibility to actually use all the goodies of ostream (like custom << operator for classes, type safety, elegant syntax...) in a way that the formating is executed AFTER the logging level is checked ?

  Read the article

• Set Page Output Cache VaryByCustom value programmatically

  - by Chris Marisic

  I want to use an Enum value for the types of VaryByCustom parameters I will support, is it possible to do this? I tried setting it in the page itself <%@ OutputCache Duration="600" VaryByParam="none" VaryByCustom='<%=VaryByCustomType.IsAuthenticated.ToString(); %>' %> But this returned the entire literal string "<%=VaryByCustomType.IsAuthenticated.ToString(); %>" inside my global.asax is there any way to do this either on the page itself or from the codebehind? Or is this just something I have to accept is purely magic strings and nothing I can do to add type safety to it?

  Read the article

• How do I handle user authorization the safest way?

  - by Irro

  I'm developing a small website where I'm going to allow user to create accounts but I'm quite clueless when it comes to safety around authorizations. I have built my project in PHP with codeigniter and found a library (Tank Auth) that could handle authorization for me. It stores password in a safe way but I'm still worried about the part when the user sends their password to my server. One easy way to do it would be to send the password in a post-request but I would guess that it's quite easy to sniff such a password. Should I do something with the password on the client side before sending it to my server? And is there any good javascript libraries for this?

  Read the article

• Which are the best techniques to protect a 'homemade' framework from unlogged visitors?

  - by Hermet

  First of all, I would like to say that I have used the search box looking for a similar question unsuccessfully, maybe because of my poor english skills. The way I currently do this is checking in every single page that a session has been opened. If not, the user gets redirected to a 404 page, to seem like the file which has been requested doesn't exist. I really don't know if this is sure or there's a better and more safety way and I'm currently working with kind of confidential data that should never become public. Could you give me some tips? Or leave a link where I could find some? Thank you very much, and again excuse me for kicking the dictionary.

  Read the article

• How to avoid Eclipse warnings when using legacy code without generics?

  - by Paul Crowley

  I'm using JSON.simple to generate JSON output from Java. But every time I call jsonobj.put("this", "that"), I see a warning in Eclipse: Type safety: The method put(Object, Object) belongs to the raw type HashMap. References to generic type HashMap should be parameterized The clean fix would be if JSONObject were genericized, but since it isn't, I can't add any generic type parameters to fix this. I'd like to switch off as few warnings as possible, so adding "@SuppressWarnings("unchecked")" to lots of methods is unappealing, but do I have any other option besides putting up with the warnings?

  Read the article

• MD5 password twice

  - by NoviceCoding

  I know MD5's safety is under question lately and this is the reason a lot of people are using salt (I dont understand this at all btw) but I was wondering if you wanted to easily implement a safe system in php can you just md5 something twice? like test 098f6bcd4621d373cade4e832627b4f6 fb469d7ef430b0baf0cab6c436e70375 So basically: $val = 'test'; $val = md5($val); $val = md5($val); Would that solve the whole rainbow security stuff? Is there an easy/noob proof way of making secure database passwords in php?

  Read the article

• Example of contravariance

  - by Misha

  I am thinking of the following example to illustrate why contravariance is useful. Let's consider a GUI framework with Widgets, Events, and Event Listeners. abstract class Event; class KeyEvent extends Event class MouseEvent extends Event trait EventListener[-Event] { def listen(e:Event) } Let Widgets define the following methods: def addKeyEventListener(listener:EventListener[KeyEvent]) def addMouseEventListener(listener:EventListener[MouseEvent]) These methods accept only "specific" event listeners, which is fine. However I would like to define also "kitchen-sink" listeners, which listen to all events, and pass such listeners to the "add listener" methods above. For instance, I would like to define LogEventListener to log all incoming events class LogEventListener extends EventListener[Event] { def listen(e:Event) { log(event) } } Since the trait EventListener is contravariant in Event we can pass LogEventListener to all those "add listener" methods without losing their type safety. Does it make sense ?

  Read the article

• How do I use Declarations (type, inline, optimize) in Scheme?

  - by kunjaan

  How do I declare the types of the parameters in order to circumvent type checking? How do I optimize the speed to tell the compiler to run the function as fast as possible like (optimize speed (safety 0))? How do I make an inline function in Scheme? How do I use an unboxed representation of a data object? And finally are any of these important or necessary? Can I depend on my compiler to make these optimizations? thanks, kunjaan.

  Read the article

• C++ Typing and OOP child classes

  - by Zack

  I'm a bit confused: If I have a base class A, and a class B which extends A, can a variable of the type A hold a value of the type B and vice versa? If yes, why? Aren't they completely different even if B is derived from A? How about type-safety? If this is possible, what things do I have to mind when taking use of this? How would this work out in terms of performance? Note: Sorry if I asked too many questions, just ignore them and just look out for those "marked" with the list decoration dot :) Also, this is not my homework. I'm a hobby programmer and have skills in scripting languages with OOP, yet I'm relatively new to OOP typing in C++.

  Read the article

• Emulating a transaction-safe SEQUENCE in MySQL

  - by Michael Pliskin

  We're using MySQL with InnoDB storage engine and transactions a lot, and we've run into a problem: we need a nice way to emulate Oracle's SEQUENCEs in MySQL. The requirements are: - concurrency support - transaction safety - max performance (meaning minimizing locks and deadlocks) We don't care if some of the values won't be used, i.e. gaps in sequence are ok. There is an easy way to archieve that by creating a separate InnoDB table with a counter, however this means it will take part in transaction and will introduce locks and waiting. I am thinking to try a MyISAM table with manual locks, any other ideas or best practices?

  Read the article

< Previous Page | 147 148 149 150 151 152 153 154 155 156 157 158  | Next Page >