Search Results

Search found 25579 results on 1024 pages for 'complex event processing'.

Page 769/1024 | < Previous Page | 765 766 767 768 769 770 771 772 773 774 775 776  | Next Page >

  • algorithm to find longest non-overlapping sequences

    - by msalvadores
    I am trying to find the best way to solve the following problem. By best way I mean less complex. As an input a list of tuples (start,length) such: [(0,5),(0,1),(1,9),(5,5),(5,7),(10,1)] Each element represets a sequence by its start and length, for example (5,7) is equivalent to the sequence (5,6,7,8,9,10,11) - a list of 7 elements starting with 5. One can assume that the tuples are sorted by the start element. The output should return a non-overlapping combination of tuples that represent the longest continuos sequences(s). This means that, a solution is a subset of ranges with no overlaps and no gaps and is the longest possible - there could be more than one though. For example for the given input the solution is: [(0,5),(5,7)] equivalent to (0,1,2,3,4,5,6,7,8,9,10,11) is it backtracking the best approach to solve this problem ? I'm interested in any different approaches that people could suggest. Also if anyone knows a formal reference of this problem or another one that is similar I'd like to get references. BTW - this is not homework. Edit Just to avoid some mistakes this is another example of expected behaviour for an input like [(0,1),(1,7),(3,20),(8,5)] the right answer is [(3,20)] equivalent to (3,4,5,..,22) with length 20. Some of the answers received would give [(0,1),(1,7),(8,5)] equivalent to (0,1,2,...,11,12) as right answer. But this last answer is not correct because is shorter than [(3,20)].

    Read the article

  • How to use a TFileStream to read 2D matrices into dynamic array?

    - by Robert Frank
    I need to read a large (2000x2000) matrix of binary data from a file into a dynamic array with Delphi 2010. I don't know the dimensions until run-time. I've never read raw data like this, and don't know IEEE so I'm posting this to see if I'm on track. I plan to use a TFileStream to read one row at a time. I need to be able to read as many of these formats as possible: 16-bit two's complement binary integer 32-bit two's complement binary integer 64-bit two's complement binary integer IEEE single precision floating-point For 32-bit two's complement, I'm thinking something like the code below. Changing to Int64 and Int16 should be straight forward. How can I read the IEEE? Am I on the right track? Any suggestions on this code, or how to elegantly extend it for all 4 data types above? Since my post-processing will be the same after reading this data, I guess I'll have to copy the matrix into a common format when done. I have no problem just having four procedures (one for each data type) like the one below, but perhaps there's an elegant way to use RTTI or buffers and then move()'s so that the same code works for all 4 datatypes? Thanks! type TRowData = array of Int32; procedure ReadMatrix; var Matrix: array of TRowData; NumberOfRows: Cardinal; NumberOfCols: Cardinal; CurRow: Integer; begin NumberOfRows := 20; // not known until run time NumberOfCols := 100; // not known until run time SetLength(Matrix, NumberOfRows); for CurRow := 0 to NumberOfRows do begin SetLength(Matrix[CurRow], NumberOfCols); FileStream.ReadBuffer(Matrix[CurRow], NumberOfCols * SizeOf(Int32)) ); end; end;

    Read the article

  • setting something disposed or invisible java

    - by OVERTONE
    this might be simple enough as just inserting the right method but i cant seem to get it right. i have a simple program with two buttons. each one changes the picture above them. but anytime i click the buttons i get some odd awt event queue error. i think its because im trying to add something to a frame after its already been made. package icnon; import javax.imageio.*; import javax.swing.*; import java.awt.*; import java.awt.event.*; public class FrameIconExample extends JFrame implements ActionListener { JLabel j; JPanel p, l, k; JButton picOne, picTwo; Container cPane; public FrameIconExample() { JButton picOne = new JButton("picOne"); JButton picTwo = new JButton("picTwo"); picOne.setName("picOne"); picTwo.setName("picTwo"); picOne.addActionListener(this); picTwo.addActionListener(this); JPanel p = new JPanel(new GridLayout(2, 1)); JPanel l = new JPanel(new FlowLayout()); JPanel k = new JPanel(new FlowLayout()); cPane = getContentPane(); j = new JLabel(new ImageIcon("../meet/src/images/beautiful-closeup-portrait-photography.jpg")); l.add(j); k.add(picOne); k.add(picTwo); p.add(l); p.add(k); add(p); } public static void main(String[] args) { FrameIconExample frame = new FrameIconExample(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(new Dimension(300, 800)); frame.setTitle("Frame Icon Example"); // Display the form frame.setVisible(true); } @Override public void actionPerformed(ActionEvent e) { JButton temp = (JButton) e.getSource(); String src = "../meet/src/images/Majken Kruse portrait - john.jpg"; //System.out.println(src + " " + temp.getName()); if(temp.getName().equalsIgnoreCase("picOne")) { src = "../meet/src/images/beautiful-closeup-portrait-photography.jpg"; System.out.println(src + " " + temp.getName()); Icon img; j = new JLabel(new ImageIcon(src)); l.add(j); System.out.println("1"); } if(temp.getName().equalsIgnoreCase("picTwo")) { src = "../icontest/images/Majken Kruse portrait - john.jpg"; System.out.println(src + " " + temp.getName()); Icon img; j = new JLabel(new ImageIcon(src)); l.add(j); System.out.println("2"); } } } its all just the one program so if you copy paste it into an editor you can see the stack trace. but the source of the image files wont be there. does anyone know how id do it? or where im goin wrong? stack trace: ../meet/src/images/beautiful-closeup-portrait-photography.jpg picOne Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at icnon.FrameIconExample.actionPerformed(FrameIconExample.java:68) at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.setPressed(Unknown Source) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source) at java.awt.Component.processMouseEvent(Unknown Source) at javax.swing.JComponent.processMouseEvent(Unknown Source) at java.awt.Component.processEvent(Unknown Source) at java.awt.Container.processEvent(Unknown Source) at java.awt.Component.dispatchEventImpl(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Window.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source)

    Read the article

  • Aligning messageformat on printing a JTable.

    - by DanielFH
    I'm using this for the moment to print out my table, and it works. But I'm not really happy with the layout of the messageformatting, I would like to have both pagenumber and date in the footer, and date format aligned to the left side of the table, and page to the right. How can I do that? Been reading some stuff about overriding the PrintTable method, but seems to get pretty complex from what I've read. Hope you can help me with this issue, thank you. :) import javax.print.attribute.HashPrintRequestAttributeSet; import javax.print.attribute.PrintRequestAttributeSet; import javax.print.attribute.standard.OrientationRequested; import javax.swing.JTable; import dk.beesys.rims.ui.WindowInventory; public class Print { private static Print INSTANCE; public static Print getInstance() { if (INSTANCE == null) { INSTANCE = new Print(); } return INSTANCE; } private Print(){ } public void printList(java.awt.event.ActionEvent ignore) { String strDate = MessageFormat.format("{0,date,short} {0,time,short}", new Date()); MessageFormat header = new MessageFormat("- {0} -"); MessageFormat footer = new MessageFormat("Printed: " + strDate); PrintRequestAttributeSet aset = new HashPrintRequestAttributeSet(); aset.add(OrientationRequested.LANDSCAPE); try { WindowInventory.getInstance().getTable().print(JTable.PrintMode.FIT_WIDTH, header, footer, true, aset, true); } catch (java.awt.print.PrinterException e) { System.err.format("Cannot print %s%n", e.getMessage()); } }

    Read the article

  • Four-color theorem in Prolog (using a dynamic predicate)

    - by outa
    Hi, I'm working on coloring a map according to the four-color theorem (http://en.wikipedia.org/wiki/Four_color_theorem) with SWI-Prolog. So far my program looks like this: colour(red). colour(blue). map_color(A,B,C) :- colour(A), colour(B), colour(C), C \= B, C \= A. (the actual progam would be more complex, with 4 colors and more fields, but I thought I'd start out with a simple case) Now, I want to avoid double solutions that have the same structure. E.g. for a map with three fields, the solution "red, red, blue" would have the same structure as "blue, blue, red", just with different color names, and I don't want both of them displayed. So I thought I would have a dynamic predicate solution/3, and call assert(solution(A,B,C)) at the end of my map_color predicate. And then, for each solution, check if they already exist as a solution/3 fact. The problem is that I would have to assert something like solution(Color1,Color1,Color2), i.e. with variables in order to make a unification check. And I can't think of a way to achieve this. So, the question is, what is the best way to assert a found solution and then make a unification test so that "red, red, blue" would unify with "blue, blue, red"?

    Read the article

  • Running game, leaving game and continuing animation

    - by Madrusec
    I have been trying to learn some Actionscript recently and have been trying to run an interactive story that at one point turns into an extremel simple shooter game. After the player either wins or looses, then he/she is taken to the rest of the animated story. So I have everything up to the point where the games runs (successfully) but for some reason I am unable to have flash run the rest of the frames, most of which have no code at all. This is the code for scene 1: stop (); import flash.display.MovieClip; import flash.events.MouseEvent; import flash.utils.Timer; import flash.events.TimerEvent; var stoneInGame:uint; var stoneMaker: Timer; var container_mc: MovieClip; var cursor:MovieClip; var score:int; var anxiety:int; var anxiety_mc :MovieClip = new mcAnxiety(); //stage.addChild( anxiety_mc ); function initializeGame():void { stoneInGame = 10; stoneMaker = new Timer(1000, stoneInGame); container_mc = new MovieClip(); addChild(container_mc); container_mc.addChild(anxiety_mc); anxiety_mc.x = 497; anxiety_mc.y = 360; stoneMaker.addEventListener(TimerEvent.TIMER, createStones); stoneMaker.start(); cursor = new Cursor(); addChild(cursor); cursor.enabled = false; Mouse.hide(); stage.addEventListener(MouseEvent.MOUSE_MOVE, dragCursor); score = 0; anxiety = anxiety_mc.totalFrames; anxiety_mc.gotoAndStop(anxiety); } function dragCursor(event:MouseEvent):void { cursor.x = this.mouseX; cursor.y = this.mouseY; } function createStones(event:TimerEvent):void { var stone:MovieClip; stone = new Stone(); stone.x = Math.random() * stage.stageWidth; stone.y = Math.random() * stage.stageHeight; container_mc.addChild(stone); } function increaseScore():void { score ++; if(score >= stoneInGame) { dragCursor.stop(); createStones.stop(); stoneMaker.stop(); trace("you wind!"); } } function decreaseAnxiety():void { anxiety--; if(anxiety <= 0) { stoneMaker.stop(); trace("you lose!"); } else { anxiety_mc.gotoAndStop(anxiety); } increaseScore(); } initializeGame(); So what I tried to do was adding gotoAndPlay() inside both the decreaseAnxiety and increaseScore functions after the trace statements and referenced a frame where I have more keyframes that continue a story. However, Flash just goes back to the beginning of the timeline and I even the functions that change and control the cursor seem to be running. This leads me to believe that I need to make sure that I tell flash o stup running certain functions before jumping to another frame. However, it seems to me that I would still have the same issue and not be able to continue in the timeline. Is there something I am missing? How can I jump out of all this code once the game finishes and simply continue playing the rest of the frames? Any pointers would be greatly appreciated. Thank you

    Read the article

  • DBD::CSV: Problem with userdefined functions

    - by sid_com
    From the SQL::Statement::Functions documentation: Creating User-Defined Functions ... More complex functions can make use of a number of arguments always passed to functions automatically. Functions always receive these values in @_: sub FOO { my( $self, $sth, $rowhash, @params ); } #!/usr/bin/env perl use 5.012; use warnings; use strict; use DBI; my $dbh = DBI->connect( "DBI:CSV:", undef, undef, { RaiseError => 1, } ); my $table = 'wages'; my $array_ref = [ [ 'id', 'number' ], [ 0, 6900 ], [ 1, 3200 ], [ 2, 1800 ], ]; $dbh->do( "CREATE TEMP TABLE $table AS import( ? )", {}, $array_ref ); sub routine { my $self = shift; my $sth = shift; my $rowhash = shift; # return $_[0] / 30; }; $dbh->do( "CREATE FUNCTION routine" ); my $sth = $dbh->prepare( "SELECT id, routine( number ) AS result FROM $table" ); $sth->execute(); $sth->dump_results(); When I try this I get an error-message: DBD::CSV::st execute failed: Use of uninitialized value $_[0] in division (/) at ./so.pl line 27. [for Statement "SELECT id, routine( number ) AS result FROM "wages""] at ./so.pl line 34. When I comment out the third argument I works as expected ( because it looks as if the third argument is missing ): #!/usr/bin/env perl ... sub routine { my $self = shift; my $sth = shift; #my $rowhash = shift; return $_[0] / 30; }; ... 0, 230 1, 106.667 2, 60 3 rows Is this a bug?

    Read the article

  • What's the proper approach for writing multi-path "story" flows?

    - by Basiclife
    Hi, I wonder if you can help me. I'm writing a game (2d) which allows players to take multiple routes, some of which branch/merge - perhaps even loop. Each section of the game will decide which section is loaded next. I'm calling each section an IStoryElement - And I'm wondering how best to link these elements up in a way that is easily changed/configured and at the same time, graphable I'm going to have an engine/factory assembly which will load the appropriate StoryElement(s) based on various config options. I initially planned to give each StoryElement a NextElement() As IStoryElement property and a Completed() event. When the vent fires, the engine reads the NextElement property to find the next StoryElement. The downside to this is that if I ever wanted to graph all the routes through the game, I would be unable to - I couldn't determine all possible targets for each StoryElement. I considered a couple of other solutions but they all feel a little clunky - eg Do I need an additional layer of abstraction? ie StoryElementPlayers or similar - Each one would be responsible for stringing together multiple StoryElement perhaps a Series and a ChoicePlayer with each responsible for graphing its own StoryElement - But this will just move the problem up a layer. In short, I need some way of emulating a simple but dynamic workflow (but I'd rather not actually use WWF). Is there a pattern for something this simple? All the ones I've managed to find relate to more advanced control flow (parallel processing, etc.)

    Read the article

  • How to optimize paging for large in memory database

    - by snakefoot
    I have an application where the entire database is implemented in memory using a stl-map for each table in the database. Each item in the stl-map is a complex object with references to other items in the other stl-maps. The application works with a large amount of data, so it uses more than 500 MByte RAM. Clients are able to contact the application and get a filtered version of the entire database. This is done by running through the entire database, and finding items relevant for the client. When the application have been running for an hour or so, then Windows 2003 SP2 starts to page out parts of the RAM for the application (Eventhough there is 16 GByte RAM on the machine). After the application have been partly paged out then a client logon takes a long time (10 mins) because it now generates a page fault for each pointer lookup in the stl-map. I can see it is possible to tell Windows to lock memory in RAM, but this is generally only recommended for device drivers, and only for "small" amounts of memory. I guess a poor mans solution could be to loop through the entire memory database, and thus tell Windows we are still interested in keeping the datamodel in RAM. I guess another poor mans solution could be to disable the pagefile completely on Windows. I guess the expensive solution would be a SQL database, and then rewrite the entire application to use a database layer. Then hopefully the database system will have implemented means to for fast access. Are there other more elegant solutions ?

    Read the article

  • How can I determine the "correct" number of steps in a questionnaire where branching is used?

    - by Mike Kingscott
    I have a potential maths / formula / algorithm question which I would like help on. I've written a questionnaire application in ASP.Net that takes people through a series of pages. I've introduced conditional processing, or branching, so that some pages can be skipped dependent on an answer, e.g. if you're over a certain age, you will skip the page that has Teen Music Choice and go straight to the Golden Oldies page. I wish to display how far along the questionnaire someone is (as a percentage). Let's say I have 10 pages to go through and my first answer takes me straight to page 9. Technically, I'm now 90% of the way through the questionnaire, but the user can think of themselves as being on page 2 of 3: the start page (with the branching question), page 9, then the end page (page 10). How can I show that I'm on 66% and not 90% when I'm on page 9 of 10? For further information, each Page can have a number of questions on that can have one or more conditions on them that will send the user to another page. By default, the next page will be the next one in the collection, but that can be over-ridden (e.g. entire sets of pages can be skipped). Any thoughts? :-s

    Read the article

  • Building a calendar navigation in Rails (controller and view links)

    - by user532339
    Trying to get the next month when clicking the link_to. I've done the following in the view. <%= form_tag rota_days_path, :method => 'get' do %> <p> <%= hidden_field_tag(:next_month, @t1) %> <%= link_to 'Next Month', rota_days_path(:next_month => @next_month)%> </p> <% end %> class RotaDaysController < ApplicationController # GET /rota_days # GET /rota_days.json # load_and_authorize_resource respond_to :json, :html def index @rota_days = RotaDay.all @hospitals = Hospital.all @t1 = Date.today.at_beginning_of_month @t2 = Date.today.end_of_month @dates = (@t1..@t2) #Concat variable t1 + t2 together # @next_month = Date.today + 1.month(params[: ??? ] #Old if params[:next_month] # @next_month = Date.today >> 1 @next_month = params[:next_month] + 1.month @t1 = @next_month.at_beginning_of_month @t2 = @next_month.end_of_month @dates = (@t1..@t2) end @title = "Rota" respond_to do |format| format.html # index.html.erb format.json { render json: @rota_days } end end I have identified that the reason why this may not be working is in because of the following in my controller @next_month = params[:next_month] + 1.month the last two called methods is defined only on time/date objects. but not on fixnum/string objects. I understand I am missing something from this Update I have found that the actual issue is that the `params[:next_month] is a string and I am trying to add a date to to it. Which means I need to convert the string to a date/time object. Console output: Started GET "/rota_days" for 127.0.0.1 at 2012-12-14 22:14:36 +0000 Processing by RotaDaysController#index as HTML User Load (0.0ms) SELECT `users`.* FROM `users` WHERE `users`.`id` = 1 LIMIT 1 RotaDay Load (0.0ms) SELECT `rota_days`.* FROM `rota_days` Hospital Load (1.0ms) SELECT `hospitals`.* FROM `hospitals` Rendered rota_days/index.html.erb within layouts/application (23.0ms) Role Load (0.0ms) SELECT `roles`.* FROM `roles` INNER JOIN `roles_users` ON `roles`.`id` = `roles_users`.`role_id` WHERE `roles_users`.`user_id` = 1 AND `roles`.`name` = 'Administrator' LIMIT 1 Completed 200 OK in 42ms (Views: 39.0ms | ActiveRecord: 1.0ms)

    Read the article

  • How to replace auto-implemented c# get body at runtime or compile time?

    - by qstarin
    I've been trying to figure this out all night, but I guess my knowledge of the .Net Framework just isn't that deep and the problem doesn't exactly Google well, but if I can get a nod in the right direction I'm sure I can implement it, one way or another. I'd like to be able to declare a property decorated with a custom attribute as such: public MyClass { [ReplaceWithExpressionFrom(typeof(SomeOtherClass))] public virtual bool MyProperty { get; } } public SomeOtherClass : IExpressionHolder<MyClass, bool> { ... } public interface IExpressionHolder<TArg, TResult> { Expression<Func<TArg, TResult>> Expression { get; } } And then somehow - this is the part I'm having trouble figuring - replace the automatically generated implementation of that getter with a piece of custom code, something like: Type expressionHolderType = LookupAttributeCtorArgTypeInDeclarationOfPropertyWereReplacing(); return ReplaceWithExpressionFromAttribute.GetCompiledExpressionFrom(expressionHolderType)(this); The main thing I'm not sure how to do is replace the automatic implementation of the get. The first thing that came to mind was PostSharp, but that's a more complicated dependency than I care for. I'd much prefer a way to code it without using post-processing attached to the build (I think that's the jist of how PostSharp sinks its hooks in anyway). The other part of this I'm not so sure about is how to retrieve the type parameter passed to the particular instantiation of the ReplaceWithExpressionFrom attribute (where it decorates the property whose body I want to replace; in other words, how do I get typeof(SomeOtherClass) where I'm coding the get body replacement). I plan to cache compiled expressions from concrete instances of IExpressionHolder, as I don't want to do that every time the property gets retrieved. I figure this has just got to be possible. At the very least I figure I should be able to search an assembly for any method decorated with the attribute and somehow proxy the class or just replace the IL or .. something? And I'd like to make the integration as smooth as possible, so if this can be done without explicitly calling a registration or initialization method somewhere that'd be super great. Thanks!

    Read the article

  • My project is no longer used - how should I feel?

    - by flybywire
    For the last two years I have been developing and supporting an important project for a big customer. The project included mining data from the customer's existing systems, processing, and displaying and updating in the customer's public home page. The project was defined as crucial by the customer and I was payed good money and flown at the customer's expense to meet key employees. Some months ago, when the project was finished and in maintainance mode, I informed the customer that I am no longer interested in doing it as I had a new opportunity that would not be compatible with my existing customer. I was payed to train one of their employees, flown to meet him, make sure everything works and that he can be safely left in charge of the project. We finished in good terms after I complied with all my obligations and they payed me all they owed me. Some days ago, just out of curiosity, I entered to their website to see how the data continues to be updated and much to my dismay I discovered that the day after my contract was finished my system was "turned off" and it ceased to feed data to the public website. Let's put it clear, there is no issue of money or broken contract here. They are in they full right to do whatever they want with my software. But it is an issue of broken "programmer's ego". Should I feel bad about it (I do). Should I care and check out with my customer if they need some help? Or is it none of my matters?

    Read the article

  • Is there a more elegant solution than an if-statement with no else clause?

    - by Jay
    In the following code, if Control (the element that trigers Toggle's first OL) is not Visible it should be set Visible and all other Controls (Controls[i]) so be Hidden. .js function Toggle(Control){ var Controls=document.getElementsByTagName("ol",document.getElementById("Quote_App")); var Control=Control.getElementsByTagName("ol")[0]; if(Control.style.visibility!="visible"){ for(var i=0;i<Controls.length;i++){ if(Controls[i]!=Control){ Reveal("hide",20,0.3,Controls[i]); }else{ Reveal("show",20,0.3,Control); }; }; }else{ Reveal("hide",20,0.3,Control); }; }; Although the function [Toggle] works fine, it is actually setting Controls[i] to Hidden even if it is already. This is easily rectified by adding an If statement as in the code below, surely there is a more elegant solution, maybe a complex If condition? .js function Toggle(Control){ var Controls=document.getElementsByTagName("ol",document.getElementById("Quote_App")); var Control=Control.getElementsByTagName("ol")[0]; if(Control.style.visibility!="visible"){ for(var i=0;i<Controls.length;i++){ if(Controls[i]!=Control){ if(Controls[i].style.visibility=="visible"){ Reveal("hide",20,0.3,Controls[i]); }; }else{ Reveal("show",20,0.3,Control); }; }; }else{ Reveal("hide",20,0.3,Control); }; }; Your help is appreciated always.

    Read the article

  • Thread mutex behaviour

    - by Alberteddu
    Hi there, I'm learning C. I'm writing an application with multiple threads; I know that when a variable is shared between two or more threads, it is better to lock/unlock using a mutex to avoid deadlock and inconsistency of variables. This is very clear when I want to change or view one variable. int i = 0; /** Global */ static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; /** Thread 1. */ pthread_mutex_lock(&mutex); i++; pthread_mutex_unlock(&mutex); /** Thread 2. */ pthread_mutex_lock(&mutex); i++; pthread_mutex_unlock(&mutex); This is correct, I think. The variable i, at the end of the executions, contains the integer 2. Anyway, there are some situations in which I don't know exactly where to put the two function calls. For example, suppose you have a function obtain(), which returns a global variable. I need to call that function from within the two threads. I have also two other threads that call the function set(), defined with a few arguments; this function will set the same global variable. The two functions are necessary when you need to do something before getting/setting the var. /** (0) */ /** Thread 1, or 2, or 3... */ if(obtain() == something) { if(obtain() == somethingElse) { // Do this, sometimes obtain() and sometimes set(random number) (1) } else { // Do that, just obtain(). (2) } } else { // Do this and do that (3) // If # of thread * 3 > 10, then set(3*10) For example. (4) } /** (5) */ Where I have to lock, and where I have to unlock? The situation can be, I think, even more complex. I will appreciate an exhaustive answer. Thank you in advance. —Alberto

    Read the article

  • [C#] how to do Exception Handling & Tracing

    - by shrimpy
    Hi all, i am reading some C# books, and got some exercise don't know how to do, or not sure what does the question mean. Problem: After working for a company for some time, your skills as a knowledgeable developer are recognized, and you are given the task of “policing” the implementation of exception handling and tracing in the source code (C#) for an enterprise application that is under constant incremental development. The two goals set by the product architect are: 100% of methods in the entire application must have at least a standard exception handler, using try/catch/finally blocks; more complex methods must also have additional exception handling for specific exceptions All control flow code can optionally write “tracing” information to assist in debugging and instrumentation of the application at run-time in situations where traditional debuggers are not available (eg. on staging and production servers). (i am not quite understand these criterias, i came from the java world, java has two kind of exception, check and unchecked exception. Developer must handle checked exception, and do logging. about unchecked exception, still do logging maybe, but most of the time we just throw it. however here comes to C#, what should i do????) Question for Problem: List rules you would create for the development team to follow, and the ways in which you would enforce rules, to achieve these goals. How would you go about ensuring that all existing code complies with the rules specified by the product architect; in particular, what considerations would impact your planning for the work to ensure all existing code complies?

    Read the article

  • Use of properties vs backing-field inside owner class

    - by whatispunk
    I love auto-implemented properties in C# but lately there's been this elephant standing in my cubicle and I don't know what to do with him. If I use auto-implemented properties (hereafter "aip") then I no longer have a private backing field to use internally. This is fine because the aip has no side-effects. But what if later on I need to add some extra processing in the get or set? Now I need to create a backing-field so I can expand my getters and setters. This is fine for external code using the class, because they won't notice the difference. But now all of the internal references to the aip are going to invoke these side-effects when they access the property. Now all internal access to the once aip must be refactored to use the backing-field. So my question is, what do most of you do? Do you use auto-implemented properties or do you prefer to always use a backing-field? What do you think about properties with side-effects?

    Read the article

  • C# expression tree for ordinary code

    - by rwallace
    It's possible to create an expression tree, if you declare it as such. But is it possible to get an expression tree for an ordinary chunk of code such as a method or property getter? What I'm trying to do is, let's say for an order processing system, I have a class for order items: class Item : Entity { [Cascade] public Document document { get; set; } public int line { get; set; } public Product product { get; set; } public string description { get; set; } public decimal qty { get; set; } public decimal price { get; set; } public decimal net { get { return qty * price; } } public VatCode vat_code { get; set; } } where the net value equals qty * price, so I'd like to declare it as such, either with a property or method, and then also have the framework introspect that expression so it can generate appropriate SQL for defining a corresponding calculated column in a corresponding database view. The most obvious way to do this would be to get the expression tree for a property getter or a method, but I can't find any indication how to do this, or that it is possible. (I have found a way to get a method body as a byte stream, but that's not what's desired here.) If that isn't possible, I suppose the recommended solution would be to declare something like a static field that is an expression tree, and compile/run it at run time for internal use, and also introspect as normal for SQL generation?

    Read the article

  • Fundamentals of Deserialization in .NET?

    - by Codehelp
    I have been working with XML for past couple of months with .NET Basically all the work I do involve XML in oneway of another so I thought it would be good to learn the serialization and deserialization part of the game. My work mostly involves the 'Deserialization' part of it. Almost every time I have an XML file which has to be used by the application that I write. An object form of the XML is the best way to use. Now initially the XML was very straight forward, just a couple of tags which would translate into a class very easily using XSD.exe tool. Things grew a bit complex with nesting of tags and I found Xsd2Code gen tool work fine. During this whole process I have been able to do my work with a lot of help from Stackoverflow community, thanks for that, but I think I have missed the forest for the trees. I need to know how Deserialization works in .NET Fundamentally, I would like to know what happens behind the scenes in taking a XML and converting it into a usable object. Code samples have helped me in the past, and as mentioned earlier the problem get's solved but the learning does not happen. So, if anyone can guide to resources that can get me started on the Deserialization part of the game, I would be thankful to them. Regards.

    Read the article

  • How can I spot subtle Lisp syntax mistakes?

    - by Marius Andersen
    I'm a newbie playing around with Lisp (actually, Emacs Lisp). It's a lot of fun, except when I seem to run into the same syntax mistakes again and again. For instance, here's something I've encountered several times. I have some cond form, like (cond ((foo bar) (qux quux)) ((or corge (grault warg)) (fred) (t xyzzy))) and the default clause, which returns xyzzy, is never carried out, because it's actually nested inside the previous clause: (cond ((foo bar) (qux quux)) ((or corge (grault warg)) (fred)) (t xyzzy)) It's difficult for me to see such errors when the difference in indentation is only one space. Does this get easier with time? I also have problems when there's a large distance between the (mal-)indented line and the line it should be indented against. let forms with a lot of complex bindings, for example, or an unless form with a long conditional: (defun test () (unless (foo bar (qux quux) (or corge (grault warg) (fred)))) xyzzy) It turns out xyzzy was never inside the unless form at all: (defun test () (unless (foo bar (qux quux) (or corge (grault warg) (fred))) xyzzy)) I auto-indent habitually and use parenthesis highlighting to avoid counting parentheses. For the most part it works like a breeze, but occasionally, I discover my syntax mistakes only by debugging. What can I do?

    Read the article

  • Need help with a memory management problem in my game model

    - by user309030
    Hi, I'm a beginner level programmer trying to make a game app for the iphone and I've encountered a possible issue with the memory management (exc_bad_access) of my program so far. I've searched and read dozens of articles regarding memory management (including apple's docs) but I still can't figure out what exactly is wrong with my codes. So I would really appreciate it if someone can help clear up the mess I made for myself. //in the .h file @property(nonatomic,retain) NSMutableArray *fencePoleArray; @property(nonatomic,retain) NSMutableArray *fencePoleImageArray; @property(nonatomic,retain) NSMutableArray *fenceImageArray; //in the .m file - (void)viewDidLoad { [super viewDidLoad]; self.gameState = gameStatePaused; fencePoleArray = [[NSMutableArray alloc] init]; fencePoleImageArray = [[NSMutableArray alloc] init]; fenceImageArray = [[NSMutableArray alloc] init]; mainField = CGRectMake(10, 35, 310, 340); .......... [NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:@selector(gameLoop) userInfo:nil repeats:YES]; } So basically, the player touches the screen to set up the fences/poles -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { if(.......) { ....... } else { UITouch *touch = [[event allTouches] anyObject]; currentTapLoc = [touch locationInView:touch.view]; NSLog(@"%i, %i", (int)currentTapLoc.x, (int)currentTapLoc.y); if(CGRectContainsPoint(mainField, currentTapLoc)) { if([self checkFence]) { onFencePole++; //this 3 set functions adds their respective objects into the 3 NSMutableArrays using addObject: [self setFencePole]; [self setFenceImage]; [self setFencePoleImage]; ....... } } else { ....... } } } } The setFence function (setFenceImage and setFencePoleImage is similar to this) -(void)setFencePole { Fence *fencePole; if (!elecFence) { fencePole = [[Fence alloc] initFence:onFencePole fenceType:1 fencePos:currentTapLoc]; } else { fencePole = [[Fence alloc] initFence:onFencePole fenceType:2 fencePos:currentTapLoc]; } [fencePoleArray addObject:fencePole]; [fencePole release]; and whenever I press a button in the game, endOpenState is called to clear away all the extra images(fence/poles) on the screen and also to remove all existing objects in the 3 NSMutableArray. Point is to remove all the objects in the NSMutableArrays but keep the array itself so it can be reused later. -(void)endOpenState { ........ int xMax = [fencePoleArray count]; int yMax = [fenceImageArray count]; for (int x = 0; x < xMax; x++) { [[fencePoleImageArray objectAtIndex:x] removeFromSuperview]; } for (int y = 0; y < yMax; y++) { [[fenceImageArray objectAtIndex:y] removeFromSuperview]; } [fencePoleArray removeAllObjects]; [fencePoleImageArray removeAllObjects]; [fenceImageArray removeAllObjects]; ........ } The crash happens here at the checkFence function. -(BOOL)checkFence { if (onFencePole == 0) { return YES; } else if (onFencePole >= 1 && onFencePole < currentMaxFencePole - 1) { CGPoint tempPoint1 = currentTapLoc; CGPoint tempPoint2 = [[fencePoleArray objectAtIndex:onFencePole-1] returnPos]; // the crash happens at this line if ([self checkDistance:tempPoint1 point2:tempPoint2]) { return YES; } else { return NO; } } else if (onFencePole == currentMaxFencePole - 1) { ...... } else { return NO; } } So the problem here is, everything works fine until checkFence is called the 2nd time after endOpenState is called. So its like tap_screen - tap_screen - press_button_to_call_endOpenState - tap screen - tap_screen - crash What I'm thinking of is that fencePoleArray got messed up when I used [fencePoleArray removeAllObjects] because it doesn't crash when I comment it out. It would really be great if someone can explain to me what went wrong. And thanks in advance.

    Read the article

  • Scheme Function to reverse elements of list of 2-list

    - by sudhirc
    This is an exercise from EOPL. Procedure (invert lst) takes lst which is a list of 2-lists and returns a list with each 2-list reversed. (define invert (lambda (lst) (cond((null? lst ) '()) ((= 2 (rtn-len (car lst))) ( cons(swap-elem (car lst)) (invert (cdr lst)))) ("List is not a 2-List")))) ;; Auxiliry Procedure swap-elements of 2 element list (define swap-elem (lambda (lst) (cons (car (cdr lst)) (car lst)))) ;; returns lengh of the list by calling (define rtn-len (lambda (lst) (calc-len lst 0))) ;; calculate length of the list (define calc-len (lambda (lst n) (if (null? lst) n (calc-len (cdr lst) (+ n 1))))) This seems to work however looks very verbose. Can this be shortened or written in more elegant way ? How I can halt the processing in any of the individual element is not a 2-list? At the moment execution proceed to next member and replacing current member with "List is not a 2-List" if current member is not a 2-list.

    Read the article

  • jQuery validate problem

    - by tohop
    Hi there. I have a jquery dialog box that pops up and takes user data through a form. Once the user is finished s/he clicks the 'ok' button. This dialog box has a few 'tabs' such that when 'ok' is clicked, we want to validate all the data given in each tab. If anything is invalid, we take the user to that tab and tell them what's wrong. However, it takes 2 clicks of 'ok' to achieve this. Here is the offending jquery: if(errors){ // display the tab with the error jQuery('#recording_tabs > div').each( function(i){ alert('we are here'); if(jQuery(this).find('*').not('label').hasClass('invalid')){ jQuery('#recording_tabs').tabs('option','selected', i); return false;// prevent further processing } }); } So what happens in the above code is that when we click 'ok' we get a 'we are here' alert for each div (tab) and then nothing happens. Clicking 'ok' again gives us the 'we are here' alert up until we are taken to the tab with the errors. So obviously the first time round the inner if statement is false for each tab which probably means jQuery hasn't registered the 'invalid' classes in time. So I tried a blank each() statement just before the main one in the hope that it would fix the problem jQuery('#recording_tabs > div').each( function(i){} ); But I got the same result. Can anyone spot anything I am missing?

    Read the article

  • iphone viewWillAppear not firing

    - by chzk
    I've read numerous posts about people having problems with viewWillAppear when you do not create your view heirarchy JUST right. My problem is I can't figure out what that means. If I create a RootViewController and call addSubView on that controller, I would expect the added view(s) to be wired up for viewWillAppear events. Does anyone have an example of a complex programmatic view heirarchy that successfully recieves viewWillAppear events at every level? Apple Docs state: Warning: If the view belonging to a view controller is added to a view hierarchy directly, the view controller will not receive this message. If you insert or add a view to the view hierarchy, and it has a view controller, you should send the associated view controller this message directly. Failing to send the view controller this message will prevent any associated animation from being displayed. The problem is that they don't describe how to do this. What the hell does "directly" mean. How do you "indirectly" add a view. I am fairly new to Cocoa and iPhone so it would be nice if there were useful examples from Apple besides the basic Hello World crap. Any help is greatly appreciated...

    Read the article

  • Is using advanced constructs (function, new, function calls) in JSON safe?

    - by Vilx-
    JSON is a nice way to pass complex data from my server side code to client side JavaScript. For example, in PHP I can write: <script type="text/javascript> var MyComplexVariable = <?= BigFancyObjectGraph.GetJSON() ?>; DoMagic(MyComplexVariable); </script> This is pretty cool, but sometimes you want to pass more than basic date, like dates or even function definitions. There is a simple and straightforward way of doing it too, like: <script type="text/javascript> var MyComplexVariable = { 'SimpleProperty' : 42, 'FunctionProperty' : function() { return 6*7; }, 'DateProperty' : new Date(989539200000), 'ArbitraryProperty' : GetTheMeaningOfLifeUniverseAndEverything() }; DoMagic(MyComplexVariable); </script> And this works like a charm on all browsers I've seen so far. But according to JSON.org such syntax is invalid. On the other hand, I've seen this syntax being used in very many places, including some popular JavaScript frameworks. So... Can I expect any problems if I use "unsupported" JSON features like the above? Why is it wrong or not?

    Read the article

< Previous Page | 765 766 767 768 769 770 771 772 773 774 775 776  | Next Page >