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  • C# app running as either Windows Form or as Console Application

    - by Aeolien
    I am looking to have one of my Windows Forms applications be run programmatically—from the command line. In preparation, I have separated the logic in its own class from the Form. Now I am stuck trying to get the application to switch back and forth based on the presence of command line arguments. Here is the code for the main class: static class Program { /// <summary> /// The main entry point for the application. /// </summary> [STAThread] static void Main() { string[] args = Environment.GetCommandLineArgs(); if (args.Length > 1) // gets passed its path, by default { CommandLineWork(args); return; } Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } private static void CommandLineWork(string[] args) { Console.WriteLine("It works!"); Console.ReadLine(); } where Form1 is my form and the It works! string is just a placeholder for the actual logic. Right now, when running this from within Visual Studio (with command line arguments), the phrase It works! is printed to the Output. However, when running the /bin/Debug/Program.exe file (or /Release for that matter) the application crashes. Am I going about this the right way? Would it make more sense (i.e. take less developer time) to have my logic class be a DLL that gets loaded by two separate applications? Or is there something entirely different that I'm not aware of? Thanks in advance!

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  • Type result with Ternary operator in C#

    - by Vaccano
    I am trying to use the ternary operator, but I am getting hung up on the type it thinks the result should be. Below is an example that I have contrived to show the issue I am having: class Program { public static void OutputDateTime(DateTime? datetime) { Console.WriteLine(datetime); } public static bool IsDateTimeHappy(DateTime datetime) { if (DateTime.Compare(datetime, DateTime.Parse("1/1")) == 0) return true; return false; } static void Main(string[] args) { DateTime myDateTime = DateTime.Now; OutputDateTime(IsDateTimeHappy(myDateTime) ? null : myDateTime); Console.ReadLine(); ^ } | } | // This line has the compile issue ---------------+ On the line indicated above, I get the following compile error: Type of conditional expression cannot be determined because there is no implicit conversion between '< null ' and 'System.DateTime' I am confused because the parameter is a nullable type (DateTime?). Why does it need to convert at all? If it is null then use that, if it is a date time then use that. I was under the impression that: condition ? first_expression : second_expression; was the same as: if (condition) first_expression; else second_expression; Clearly this is not the case. What is the reasoning behind this? (NOTE: I know that if I make "myDateTime" a nullable DateTime then it will work. But why does it need it? As I stated earlier this is a contrived example. In my real example "myDateTime" is a data mapped value that cannot be made nullable.)

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  • Best practice Unit testing abstract classes?

    - by Paul Whelan
    Hello I was wondering what the best practice is for unit testing abstract classes and classes that extend abstract classes. Should I test the abstract class by extending it and stubbing out the abstract methods and then test all the concrete methods? Then only test the methods I override and the abstract methods in the unit tests for objects that extend my abstract class. Should I have an abstract test case that can be used to test the methods of the abstract class and extend this class in my test case for objects that extend the abstract class? EDIT: My abstract class has some concrete methods. I would be interested to see what people are using. Thanks Paul

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  • Dynamically showing fields to a Dev Express Grid view on windows form

    - by Bhaskar
    In one of windows application in C# , I am using Dev Express Grid view control to bind some data and display it to user. I have custom business objects with properties defined for this purpose.Then I simple set the DataSource of the grid to the list of my custom business objects. A while ago , there came a requirement which means that the columns to be displayed on to the grid will be dynamic. This means I cannot know at design time which fields I will need to display. I was thinking of abandoning setting the DataSource and populating the grid manually by code. But I think this will cause many of the grid's features not to work properly, for example , grouping the data by drag n drop of fields to the header area etc. Is there any way to tell a grid at runtime to skip certain fields from a list of BO's when databinding to the grid ?

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  • In Java it seems Public constructors are always a bad coding practice

    - by Adam Gent
    This maybe a controversial question and may not be suited for this forum (so I will not be insulted if you choose to close this question). It seems given the current capabilities of Java there is no reason to make constructors public ... ever. Friendly, private, protected are OK but public no. It seems that its almost always a better idea to provide a public static method for creating objects. Every Java Bean serialization technology (JAXB, Jackson, Spring etc...) can call a protected or private no-arg constructor. My questions are: I have never seen this practice decreed or written down anywhere? Maybe Bloch mentions it but I don't own is book. Is there a use case other than perhaps not being super DRY that I missed? EDIT: I explain why static methods are better. .1. For one you get better type inference. For example See Guava's http://code.google.com/p/guava-libraries/wiki/CollectionUtilitiesExplained .2. As a designer of the class you can later change what is returned with a static method. .3. Dealing with constructor inheritance is painful especially if you have to pre-calculate something.

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  • Reuse implemented business classes in a web applications

    - by Mohammad
    I have implemented my domain layer classes and i have used them in a java application. Now i want to use same classes in a java web application,but i dont know how can i do it? In the java aplication we make and run some objects in main(class and method) and use them while program is running. for example an object that hold a collection of data that will be needed for all user requests. My question is: How can i create and hold such objects and data that should be available for all users and clients.

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  • Scheme: what are the benefits of letrec?

    - by Ixmatus
    While reading "The Seasoned Schemer" I've begun to learn about letrec. I understand what it does (can be duplicated with a Y-Combinator) but the book is using it in lieu of recurring on the already defined function operating on arguments that remain static. An example of an old function using the defined function recurring on itself (nothing special): (define (substitute new old lat) (cond ((null? l) '()) ((eq? (car l) old) (cons new (substitute new old (cdr l)))) (else (cons (car l) (substitute new old (cdr l)))))) Now for an example of that same function but using letrec: (define (substitute new old lat) (letrec ((replace (lambda (l) (cond ((null? l) '()) ((eq? (car l) old) (cons new (replace (cdr l)))) (else (cons (car l) (replace (cdr l)))))))) (replace lat))) Aside from being slightly longer and more difficult to read I don't know why they are rewriting functions in the book to use letrec. Is there a speed enhancement when recurring over a static variable this way because you don't keep passing it?? Is this standard practice for functions with arguments that remain static but one argument that is reduced (such as recurring down the elements of a list)? Some input from more experienced Schemers/LISPers would help!

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  • Android: Deciding between SurfaceView and OpenGL (GLSurfaceView)

    - by Rich
    Is there a way to decide up front based on the expected complexity of a game/app in the planning phase whether to use regular Canvas drawing in a SurfaceView or to go with OpenGL? I've been playing around with a Canvas and only need 2D movement, and on a fairly new phone I'm getting pretty decent performance with a bunch of primitive objects and a few bitmaps running around the screen on a solid background. Is it fair to say that if I'm going to be drawing background images and increasing the number of objects being moved and drawn on top of them that I should go straight to OpenGL?

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  • Speeding up templates in GAE-Py by aggregating RPC calls

    - by Sudhir Jonathan
    Here's my problem: class City(Model): name = StringProperty() class Author(Model): name = StringProperty() city = ReferenceProperty(City) class Post(Model): author = ReferenceProperty(Author) content = StringProperty() The code isn't important... its this django template: {% for post in posts %} <div>{{post.content}}</div> <div>by {{post.author.name}} from {{post.author.city.name}}</div> {% endfor %} Now lets say I get the first 100 posts using Post.all().fetch(limit=100), and pass this list to the template - what happens? It makes 200 more datastore gets - 100 to get each author, 100 to get each author's city. This is perfectly understandable, actually, since the post only has a reference to the author, and the author only has a reference to the city. The __get__ accessor on the post.author and author.city objects transparently do a get and pull the data back (See this question). Some ways around this are Use Post.author.get_value_for_datastore(post) to collect the author keys (see the link above), and then do a batch get to get them all - the trouble here is that we need to re-construct a template data object... something which needs extra code and maintenance for each model and handler. Write an accessor, say cached_author, that checks memcache for the author first and returns that - the problem here is that post.cached_author is going to be called 100 times, which could probably mean 100 memcache calls. Hold a static key to object map (and refresh it maybe once in five minutes) if the data doesn't have to be very up to date. The cached_author accessor can then just refer to this map. All these ideas need extra code and maintenance, and they're not very transparent. What if we could do @prefetch def render_template(path, data) template.render(path, data) Turns out we can... hooks and Guido's instrumentation module both prove it. If the @prefetch method wraps a template render by capturing which keys are requested we can (atleast to one level of depth) capture which keys are being requested, return mock objects, and do a batch get on them. This could be repeated for all depth levels, till no new keys are being requested. The final render could intercept the gets and return the objects from a map. This would change a total of 200 gets into 3, transparently and without any extra code. Not to mention greatly cut down the need for memcache and help in situations where memcache can't be used. Trouble is I don't know how to do it (yet). Before I start trying, has anyone else done this? Or does anyone want to help? Or do you see a massive flaw in the plan?

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  • How to build boost foreach cycle

    - by Ockonal
    Hi guys! I have some abstract class called IClass (has pure virtual function). There are some classes which inherit IClass: CFirst, CSecond. I want to add objects of classes which inherit into boost::ptr_vector: class IClass { virtual void someFunc() = 0; }; class CFirst : public IClass { }; class CSecond : public IClass { }; boost::ptr_vector<IClass> objectsList; objectsList.push_back(new CFirst()); objectsList.push_back(new CSecond()); And now my goal is to call function (which is declarated in IClass) from all objects in objectsList. I'd prefer to use BOOST_FOREACH: foreach(IClass tempObj, objectsList) { tempObj.someFunc(); } The problem is that IClass - abstract class, so I can't make instance of it for the foreach-cycle. What should I do?

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  • Why this code showing error in W3C validator?

    - by metal-gear-solid
    Why this code showing error in W3C validator "character data is not allowed here" <blockquote>all visible objects, man, are but as pasteboard masks. But in each event -- in the living act, the undoubted deed -- there, some unknown but still reasoning thing puts forth the mouldings of its feature from behind the unreasoning mask. If man will strike, strike through the mask. All visible objects, man, are but as pasteboard masks. But in each event -- in the living act, the undoubted deed -- there, some unknown but still reasoning thing puts forth the mouldings of its feature from behind the unreasoning mask. If man will strike, strike through the mask.</blockquote> It does not giving any error in this validator http://www.onlinewebcheck.com/ and not in https://addons.mozilla.org/en-US/firefox/addon/249/

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  • How do I find the "concrete class" of a django model baseclass

    - by Mr Shark
    I'm trying to find the actual class of a django-model object, when using model-inheritance. Some code to describe the problem: class Base(models.model): def basemethod(self): ... class Child_1(Base): pass class Child_2(Base): pass If I create various objects of the two Child classes and the create a queryset containing them all: Child_1().save() Child_2().save() (o1, o2) = Base.objects.all() I want to determine if the object is of type Child_1 or Child_2 in basemethod, I can get to the child object via o1.child_1 and o2.child_2 but that reconquers knowledge about the childclasses in the baseclass. I have come up with the following code: def concrete_instance(self): instance = None for subclass in self._meta.get_all_related_objects(): acc_name = subclass.get_accessor_name() try: instance = self.__getattribute__(acc_name) return instance except Exception, e: pass But it feels brittle and I'm not sure of what happens when if I inherit in more levels.

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  • An Efficient data structure for Sorted List

    - by holydiver
    I want to save my objects according to a key in the attributes of my object in a sorted fashion. Later on I'll access these objects sequentially from max key to min key. I'll do some search tasks as well. I consider to use either AVL tree or RB Tree. As far as i know they are nearly equivalent in theory(Both have O(logn)). But in practice which one might be better in performance in my situation. And is there a better alternative than those, considering that I'll mostly do insert and sequentially access to the ds.

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  • Why aren't my coordinates matching my JFrame size?

    - by AsLanFromNarnia
    I want to do some drawing in a JPanel but the enclosing JFrame size doesn't seem to match where I've asked the coordinates to be drawn. In my example code, the JFrame size is set to (700, 700) and the last point is drawn at (600, 600). I would expect this point to be drawn 100 pixels away from the right and bottom edges but it isn't (please see screenshot). Here's the code I'm using: import java.awt.Graphics; import javax.swing.JFrame; import javax.swing.JPanel; public class Scratch extends JPanel { static int frameWidth = 700; static int frameHeight = 700; public static void main(String[] args) { JFrame frame = new JFrame(); frame.setSize(frameWidth, frameHeight); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Scratch scratch = new Scratch(); frame.getContentPane().add(scratch); frame.setVisible(true); } @Override public void paintComponent(Graphics g) { g.drawRect(100, 100, 1, 1); g.drawString("100", 100, 100); g.drawRect(200, 200, 1, 1); g.drawString("200", 200, 200); g.drawRect(300, 300, 1, 1); g.drawString("300", 300, 300); g.drawRect(400, 400, 1, 1); g.drawString("400", 400, 400); g.drawRect(500, 500, 1, 1); g.drawString("500", 500, 500); g.drawRect(600, 600, 1, 1); g.drawString("600", 600, 600); } }

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  • Finding the index of a queue that holds a member of a containing object for a given value

    - by Luke Mcneice
    I have a Queue that contains a collection of objects, one of these objects is a class called GlobalMarker that has a member called GlobalIndex. What I want to be able to do is find the index of the queue where the GlobalIndex contains a given value (this will always be unique). Simply using the Contains method shown below returns a bool. How can I obtain the queue index of this match? RealTimeBuffer .OfType<GlobalMarker>() .Select(o => o.GlobalIndex) .Contains(INT_VALUE);

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  • Accessing running task scheduled with java.util.Timer

    - by jbatista
    I'm working on a Java project where I have created a class that looks like this (abridged version): public class Daemon { private static Timer[] timerarray=null; private static Daemon instance=null; protected Daemon() { ArrayList<Timer> timers = new ArrayList<Timer>(); Timer t = new Timer("My application"); t.schedule(new Worker(), 10000,30000); timers.add(t); //... timerarray = timers.toArray(new Timer[]{}); } public static Daemon getInstance() { if(instance==null) instance=new Daemon(); return instance; } public SomeClass getSomeValueFromWorker() { return theValue; } ///////////////////////////////////////////// private class Worker extends TimerTask { public Worker() {} public void run() { // do some work } public SomeReturnClass someMethod(SomeType someParameter) { // return something; } } ///////////////////////////////////////////// } I start this class, e.g. by invoking daemon.getInstance();. However, I'd like to have some way to access the running task objects' methods (for example, for monitoring the objects' state). The Java class java.util.Timer does not seem to provide the means to access the running object, it just schedules the object instance extending TimerTask. Are there ways to access the "running" object instanciated within a Timer? Do I have to subclass the Timer class with the appropriate methods to somehow access the instance (this "feels" strange, somehow)? I suppose someone might have done this before ... where can I find examples of this "procedure"? Thank you in advance for your feedback.

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  • Recommendations for an in memory database vs thread safe data structures

    - by yx
    TLDR: What are the pros/cons of using an in-memory database vs locks and concurrent data structures? I am currently working on an application that has many (possibly remote) displays that collect live data from multiple data sources and renders them on screen in real time. One of the other developers have suggested the use of an in memory database instead of doing it the standard way our other systems behaves, which is to use concurrent hashmaps, queues, arrays, and other objects to store the graphical objects and handling them safely with locks if necessary. His argument is that the DB will lessen the need to worry about concurrency since it will handle read/write locks automatically, and also the DB will offer an easier way to structure the data into as many tables as we need instead of having create hashmaps of hashmaps of lists, etc and keeping track of it all. I do not have much DB experience myself so I am asking fellow SO users what experiences they have had and what are the pros & cons of inserting the DB into the system?

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  • Explanation of contribute_to_class

    - by anon.
    I'm attempted to extend code, and have come across an issue, I don't understand a line of code. I know the outcome of it - but I don't understand how it happens and am naturally enough scared to change it. The line of code I've come across is this: MyGenericRelation().contribute_to_class(model, 'field_name') The result of this code is a field with 'field_name' is added to the 'model' and from what I gather the objects inside the field are a list of type X (part of MyGenericRelation). I'm wondering if anyone can explain how this works. As in, why do I get a list of X objects attached to 'field_name' and if does it have to be generic relations prior to contribute_to_class or would using an actual model type, say 'Y' just give me a list of Y's. To be honest, I am more interested in the affect and functionality of the contribute_to_class method.

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  • Enumerable Contains Enumerable

    - by Tim
    For a method I have the following parameter IEnumerable<string> tags and with to query a list of objects, let's call them Post, that contains a property IEnumerable<string> Tags { get; set; }. My question is: How do I use linq to query for objects that contains all the tags from the tags parameter? private List<Post> posts = new List<Post>(); public IEnumerable<Post> GetPostsWithTags(IEnumerable<string> tags) { return ???; }

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  • MVC validation error with strongly typed view

    - by Remnant
    I have a simple form that I would like to validate on form submission. Note I have stripped out the html for ease of viewing <%=Html.TextBox("LastName", "")%> //Lastname entry <%=Html.ValidationMessage("LastName")%> <%=Html.TextBox("FirstName", "")%>//Firstname entry <%=Html.ValidationMessage("FirstName")%> <%=Html.DropDownList("JobRole", Model.JobRoleList)%> //Dropdownlist of job roles <% foreach (var record in Model.Courses) // Checkboxes of different courses for user to select { %> <li><label><input type="checkbox" name="Courses" value="<%=record.CourseName%>" /><%= record.CourseName%></label></li> <% } %> On submission of this form I would like to check that both FirstName and LastName are populated (i.e. non-zero length). In my controller I have: public ActionResult Submit(string FirstName, string LastName) { if (FirstName.Trim().Length == 0) ModelState.AddModelError("FirstName", "You must enter a first name"); if (LastName.Trim().Length == 0) ModelState.AddModelError("LastName", "You must enter a first name"); if (ModelState.IsValid) { //Update database + redirect to action } return View(); //If ModelState not valid, return to View and show error messages } Unfortunately, this code logic produces an error that states that no objects are found for JobRole and Courses. If I remove the dropdownlist and checkboxes then all works fine. The issue appears to be that when I return the View the view is expecting objects for the dropwdownlist and checkboxes (which is sensible as that is what is in my View code) How can I overcome this problem? Things I have considered: In my controller I could create a JobRoleList object and Course object to pass to the View so that it has the objects to render. The issue with this is that it will overwrite any dropdownlist / checkbox selections that the user has already made. In the parameters of my controller method Submit I could aslo capture the JobRoleList object and Course object to pass back to the View. Again, not sure this would capture any items the user has already selected. I have done much googling and reading but I cannot find a good answer. When I look at examples in books or online (e.g. Nerddinner) all the validation examples involve simple forms with TextBox inputs and don't seems to show instances with multiple checkboxes and dropdownlists. Have I missed something obvious here? What would be best practice in this situation? Thanks

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  • Why is django admin not accepting Nullable foreign keys?

    - by p.g.l.hall
    Here is a simplified version of one of my models: class ImportRule(models.Model): feed = models.ForeignKey(Feed) name = models.CharField(max_length=255) feed_provider_category = models.ForeignKey(FeedProviderCategory, null=True) target_subcategories = models.ManyToManyField(Subcategory) This class manages a rule for importing a list of items from a feed into the database. The admin system won't let me add an ImportRule without selecting a feed_provider_category despite it being declared in the model as nullable. The database (SQLite at the moment) even checks out ok: >>> .schema ... CREATE TABLE "someapp_importrule" ( "id" integer NOT NULL PRIMARY KEY, "feed_id" integer NOT NULL REFERENCES "someapp_feed" ("id"), "name" varchar(255) NOT NULL, "feed_provider_category_id" integer REFERENCES "someapp_feedprovidercategory" ("id"), ); ... I can create the object in the python shell easily enough: f = Feed.objects.get(pk=1) i = ImportRule(name='test', feed=f) i.save() ...but the admin system won't let me edit it, of course. How can I get the admin to let me edit/create objects without specifying that foreign key?

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  • P/Invoke declarations should not be safe-critical

    - by Bobrovsky
    My code imports following native methods: DeleteObject, GetFontData and SelectObject from gdi32.dll GetDC and ReleaseDC from user32.dll I want to run the code in full trust and medium trust environments (I am fine with exceptions being thrown when these imported methods are indirectly used in medium trust environments). When I run Code Analysis on the code I get warnings like: CA5122 P/Invoke declarations should not be safe-critical. P/Invoke method 'GdiFont.DeleteObject(IntPtr)' is marked safe-critical. Since P/Invokes may only be called by critical code, this declaration should either be marked as security critical, or have its annotation removed entirely to avoid being misleading. Could someone explain me (in layman terms) what does this warning really mean? I tried putting these imports in static SafeNativeMethods class as internal static methods but this doesn't make the warnings go away. I didn't try to put them in NativeMethods because after reading this article I am unsure that it's the right way to go because I don't want my code to be completely unusable in medium trust environments (I think this will be the consequence of moving imports to NativeMethods). Honestly, I am pretty much confused about the real meaning of the warning and consequences of different options to suppressing it. Could someone shed some light on all this? EDIT: My code target .NET 2.0 framework. Assembly is marked with [assembly: AllowPartiallyTrustedCallers] Methods are declared like this: [DllImport("gdi32")] internal static extern int DeleteObject(HANDLE hObject);

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  • R: Using sapply on vector of POSIXct

    - by Chris
    I have what may be a very simple question. I want to process a column of POSIXct objects from a dataframe and generate a vector of datetime strings. I tried to use the following sapply call dt <- sapply(df$datetime, function(x) format(x,"%Y-%m-%dT%H:%M:%S")) but to no avail. I keep getting the following error Error in prettyNum(.Internal(format(x, trim, digits, nsmall, width, 3L, : invalid 'trim' argument When I apply this function to a single POSIXct object from the column, I have no problem. So I'm stumped at the moment about what the problem is. Do I need to do something special with POSIXct objects?

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  • Castle ActiveRecord: session error search and access to lazy loading property in different threads

    - by sc911
    Hi *, I've got a problem with an multi-threaded desktop application using Castle ActiveRecord in C#: To keep the GUI alive while searching for the objects based on userinput I'm using the BackgroundWorker for the search-function. Some of the properties of the objects, especially some HasMany-Relations, are marked as Lazy. Now, when the search is finished and the user selects an resulting object, some of the properties of this object should be displayed. But as the search was done by the BackgroundWorker in a different thread, accessing the properties fails as the session for the lazy-access is no longer available. What will be the best way to do the search in an extra thread to keep the GUI alive and to access all properties correctly including those marked as lazy? Thanks for any advise! Regards sc911

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  • to connect matlab with java

    - by user304005
    Through the below given code I was able to connect to matlab. But I was not able to execute the script file containing matlab code...Please help me to modify the code so as to execute the matlab code.... Here luck2 is a .m file.... import java.io.InputStreamReader; import java.io.*; public class matlab { private static File myMATLABScript; public static String runScript(File luck2) { String output = "" ; String error = ""; try { String commandToRun ="C:\\Program Files\\MATLAB\\R2009a\\bin\\matlab -nodisplay <" + "Z:\\sem\\java\\luck2"; //String commandToRun = "matlab -nosplash -r myMATLABScript -nodisplay -nodesktop < " + opentxt; System.out.println(commandToRun); Process p = Runtime.getRuntime().exec(commandToRun); String s; BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream())); BufferedReader stdError = new BufferedReader(new InputStreamReader(p.getErrorStream())); System.out.println("\nHere is the standard output of the command:\n"); while ((s = stdInput.readLine()) != null) { System.out.println("haiiiiiiiiiiii"); output = s + "\n"; System.out.println(s); } while ((s = stdError.readLine()) != null) { error = s + "\n"; System.out.println(s); } } catch (Exception e) { System.out.println("exception happened here what I know:"); e.printStackTrace(); System.exit(-1); } return output + error; } public static void main(String[] args) throws IOException { matlab m = new matlab(); matlab.runScript(myMATLABScript); //matlab.runScript(); } }

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