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  • Why do I have to explicitly cast sometimes for varargs?

    - by Daniel Lew
    I've got a Class that uses reflection a lot, so I wrote a method to help out: private <T> T callMethod(String methodName, Class[] parameterTypes, Object[] args) { try { Class c = mVar.getClass(); Method m = c.getMethod(methodName, (Class[]) parameterTypes); return (T) m.invoke(mVar, args); } // Insert exception catching here [...] } This worked well for any method that had parameters, however I had to explicitly cast parameterTypes to Class[] in order for this to work for methods with no parameters (e.g., callMethod('funName', null, null);). I've been trying to figure out why this is the case. It seems to me that if parameterTypes, when null, had no concept of what type it is (Class[]), then I'd need to cast it for getMethod(). But if that's the case, why is getMethod() able to tell the difference between null, and (Class[]) null when the method is invoked?

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  • Refactoring common method header and footer

    - by David Wong
    I have the following chunk of header and footer code appearing in alot of methods. Is there a cleaner way of implementing this? Session sess = factory.openSession(); Transaction tx; try { tx = sess.beginTransaction(); //do some work ... tx.commit(); } catch (Exception e) { if (tx!=null) tx.rollback(); throw e; } finally { sess.close(); } The class in question is actually an EJB 2.0 SessionBean which looks like: public class PersonManagerBean implements SessionBean { public void addPerson(String name) { // boilerplate // dostuff // boilerplate } public void deletePerson(Long id) { // boilerplate // dostuff // boilerplate } }

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  • Linq Query to IEnumerable<T> Extension Method

    - by CSharpNoob
    Consider this, class Item { public string ID { get; set;} public string Description { get; set; } } class SaleItem { public string ID { get; set;} public string Discount { get; set; } } var itemsToRemoved = (List<Item>)ViewState["ItemsToRemove"]; // get only rows of ID var query = from i in itemsToRemoved select i.ID; var saleItems= (List<SaleItem>)ViewState["SaleItems"]; foreach (string s in query.ToArray()) { saleItems.RemoveItem(s); } How can I write this LINQ phrase using IEnumerable/List Extension methods // get only rows of ID var query = from i in items select i.ID; thanks in advance.

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  • Rails architecture questions

    - by justinbach
    I'm building a Rails site that, among other things, allows users to build their own recipe repository. Recipes are entered either manually or via a link to another site (think epicurious, cooks.com, etc). I'm writing scripts that will scrape a recipe from these sites given a link from a user, and so far (legal issues notwithstanding) that part isn't giving me any trouble. However, I'm not sure where to put the code that I'm writing for these scraper scripts. My first thought was to put it in the recipes model, but it seems a bit too involved to go there; would a library or a helper be more appropriate? Also, as I mentioned, I'm building several different scrapers for different food websites. It seems to me that the elegant way to do this would be to define an interface (or abstract base class) that determines a set of methods for constructing a recipe object given a link, but I'm not sure what the best approach would be here, either. How might I build out these OO relationships, and where should the code go?

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  • Would you make this method Static or not?

    - by Adam Drummond
    During a code review I presented a method quickly to the team that I had made static and one person agreed that there was no reason for it to not be static and a person disagreed saying that he would not make it static because it wasn't necessary and just to be on the safe side for future modifications and testing. So I did quite a bit of research and obviously it's a specialized case but I would like to know what you would do in this situation and why? (Its basically a helper method I call from a few different methods, a very low traffic page. More for my knowledge and learning on Static.) private IEnumerable<Category> GetCategoryByID(int id, Context context) { var categoryQuery = from selectAllProc in context.SelectAll_sp() where selectAllProc.CategoryID == id select selectAllProc; return categoryQuery; }

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  • Rails + simple role system through associative table

    - by user202411
    So I have the Ninja model which has many Hovercrafts through ninja_hovercrafts (which stores the ninja_id and the hovercraft_id). It is of my understanding that this kind of arrangement should be set in a way that the associative table stores only enough information to bind two different classes. But I'd like to use the associative table to work as a very streamlined authorization hub on my application. So i'd also like this table to inform my system if this binding makes the ninja the pilot or co-pilot of a given hovercraft, through a "role" field in the table. My questions are: Is this ugly? Is this normal? Are there methods built into rails that would help me to automagically create Ninjas and Hovercrafts associations WITH the role? For exemple, could I have a nested form to create both ninjas and hcs in a way that the role field in ninjas_hovercrafts would be also filled? If managing my application roles this way isn't a good idea, whats the non-resource heavy alternative (my app is being designed trying to avoid scalability problems such as excessive joins, includes, etc) thank you

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  • Weird <T> Activator Question.

    - by j-t-s
    Hello, I'm sorry, but a while ago I wrote a piece of code that was so nice. And now I'm trying to remember it for a new project. All I can remember about it is that it looked something like this: public static Create<T>() *something missing here* : *Something missing here* { // add methods etc here. I also think I remember something like " Activator.CreateInstance" being used. But I'm not sure. } Has anybody written code like this before? Basically what it did was it created a control and passed it back to another project. Thank you jt

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  • C5 Generics Collection IntervalHeap<T> -- getting an IPriorityQueueHandle from a T for Replace or De

    - by Jared Updike
    I'm using the Generics Collection library C5 (server down :-( ) and I have an IntervalHeap(T) and I need to Delete or Replace a T that is not the Max or Min. How do I get an IPriorityQueueHandle from my T? The C5 library source code shows that IPriorityQueueHandle(T) has no methods or properties to implement and the compiler thinks my implementation of IPriorityQueueHandle(T) for my T is acceptable. I try to use a T like this: q.Replace(t, t); and the C5 library throws an InvalidCastException because it cannot convert my T to a (Handle).

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  • C++ - how does Sleep() and cin work?

    - by quano
    Just curious. How does actually the function Sleep() work (declared in windows.h)? Maybe not just that implementation, but anyone. With that I mean - how is it implemented? How can it make the code "stop" for a specific time? Also curious about how cin and those actually work. What do they do exactly? The only way I know how to "block" something from continuing to run is with a while loop, but considering that that takes a huge amount of processing power in comparison to what's happening when you're invoking methods to read from stdin (just compare a while (true) to a read from stdin), I'm guessing that isn't what they do.

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  • Difference between var and Class class in object creation

    - by Divine
    Its a silly question, however shocked to see different behaviors. Learning a lot. Lets say I have two classes below Class A { public void Display() { } } Class B : A { public void Display() { } } Class C : B { public void Display() { } } Class Final { static void Main() { var c = new C(); // B c = new C(); //My doubt is, both of the above gives different results. May I know B c = new C() creates object of B or C? What I understood is, it creates object of B. Then why we say "new C()"? I agree with C c = new C(); But I thought, B b = new C(); creates object of B. Where we use this style? Only when utilizing runtime polymorphism? (Overriding methods)? } }

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  • Looking for Info on a Javascript Testing framework

    - by DaveDev
    Hi Can somebody fill me in on JavaScript Testing Frameworks? I'm working on a project now and as the JS (Mostly jQuery) libraries grow, it's getting more and more difficult to introduce change or refactor, because I have no way of guaranteeing the accuracy of the code without manually testing everything. I don't really know anything about JavaScript Testing Frameworks, or how they integrate/operate in a .Net project, so I thought I'd ask here. What would a good testing framework be for .Net? What does a JavaScript test look like? (e.g. with NUnit, I have [TestFixture] classes & [Test] methods in a ProjectTests assembly) How do I run a javascript test? What are the conceptual differences between testing JS & testing C#? Is there anything else that would be worth knowing? Thanks Dave

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  • nodejs, mongodb - How do I operate on data from multiple queries?

    - by Ryan
    Hi all, I'm new to JS in general, but I am trying to query some data from MongoDB. Basically, my first query retrieves information for the session with the specified session id. The second query does a simple geospacial query for documents with a location near the specified location. I'm using the mongodb-native javascript driver. All of these query methods return their results in callbacks, so they're non-blocking. This is the root of my troubles. What I'm needing to do is retrieve the results of the second query, and create an Array of sessionIds of all the returned documents. Then I'm going to pass those to a function later. But, I can't generate this array and use it anywhere outside the callback. Does anyone have any idea how to properly do this? http://dpaste.org/wXiE/

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  • Get controller method caller (3rd party webservice)

    - by bastijn
    Is it possible to retrieve the URL of a 3rd party webservice calling my controller method? Things like Request.Current.Url refer to my own URL (/someController/someAction/). The 3rd party webservice is sending HTTP POST data to my /someController/someAction and I wish to send back a HTTP POST message to the caller of the method, the 3rd party webservice, without using return Content["some response"] which will force me to exit the method. Since the answer is plain text I would like to send it using HTTP Post. What I actually try to do is respond to the calling webservice without exiting my method (return Content() will exit) so I can call other methods to process the data send to me by the webservice. I want to first tell the webservice I received their stuff and than process, in this way when a processing error occurs the webservice at least will not resend old data. Is there another way to do this than building your own HTTP post?

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  • What's causing "Unable to retrieve native address from ByteBuffer object"?

    - by r0u1i
    As a very novice Java programmer, I probably should not mess with that kind of things. Unfortunately, I'm using a library which have a method that accepts a ByteBuffer object and throws when I try to use it: Exception in thread "main" java.lang.NullPointerException: Unable to retrieve native address from ByteBuffer object Is it because I'm not using a non-direct buffer? edit: There's not a lot of my code there. The library I'm using is jNetPcap, and I'm trying to dump a packet to file. My code takes an existing packet, and extract a ByteBuffer out of it: byte[] bytes = m_packet.getByteArray(0, m_packet.size()); ByteBuffer buffer = ByteBuffer.wrap(bytes); Then it calls on of the dump methods of jNetPcap that takes a ByteBuffer.

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  • how to save state of dynamically created editTexts

    - by user922531
    I'm stuck at how to save the state of my EditTexts on screen orientation. Currently if text is inputted into the EditTexts and the screen is orientated, the fields are wiped (as expected). I am already calling onSaveInstanceState and saving a String, but I have no clue on how to save the EditTexts which are created in code and then retrieve them and add them to the EditTexts when redrawing the activity. Snippet of my code: My main activity is as follows: public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // get the multidim array b = getIntent().getBundleExtra("obj"); m = (Methods) b.getSerializable("Methods"); // method to draw the layout InitialiseUI(); // Restore UI state from the savedInstanceState. if (savedInstanceState != null) { String strValue = savedInstanceState.getString("light"); if (strValue != null) { FLight = strValue; } } try { mCamera = Camera.open(); if (FLight.equals("true")) { flashLight(); } } catch (Exception e) { Log.d(TAG, "Thrown exception onCreate() camera: " + e); } } // end onCreate /** Called when the back button is pressed. */ @Override public void onResume() { super.onResume(); try { mCamera = Camera.open(); if (FLight.equals("true")) { flashLight(); } } catch (Exception e) { Log.d(TAG, "Thrown exception onCreate() camera: " + e); } } // end onCreate /** saves data before leaving the screen */ @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putString("light", FLight); } /** called when exiting / leaving the screen */ @Override protected void onPause() { super.onPause(); Log.d(TAG, "onPause()"); if (mCamera != null) { mCamera.stopPreview(); mCamera.release(); mCamera = null; } } /* * set up the UI elements - add click listeners to buttons used in * onCreate() and onConfigurationChanged() * * Set the editTexts fields to show the previous readings as Hints */ public void InitialiseUI() { Log.d(TAG, "Start of InitialiseUI, Main activity"); // get a reference to the TableLayout final TableLayout myTLreads = (TableLayout) findViewById(R.id.myTLreads); // Create arrays to hold the TVs and ETs final TextView[] myTextViews = new TextView[m.getNoRows()]; // create an empty array; final EditText[] myEditTexts = new EditText[m.getNoRows()]; // create an empty array; for(int i =0; i<=m.getNoRows()-1;i++ ){ TableRow tr=new TableRow(this); tr.setLayoutParams(new LayoutParams( LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT)); // create a new textview / editText final TextView rowTextView = new TextView(this); final EditText rowEditText = new EditText(this); // setWidth is needed otherwise my landscape layout is OFF rowEditText.setWidth(400); // this stops the keyboard taking up the whole screen in landscape layout rowEditText.setImeOptions(EditorInfo.IME_FLAG_NO_EXTRACT_UI); // add some padding to the right of the TV rowTextView.setPadding(0,0,10,0); // set colors to white rowTextView.setTextColor(Color.parseColor("#FFFFFF")); rowEditText.setTextColor(Color.parseColor("#FFFFFF")); // if readings already sent today set color to yellow if(m.getTransmit(i+1)==false){ rowEditText.setEnabled(false); rowEditText.setHintTextColor(Color.parseColor("#FFFF00")); } // set the text of the TV to the meter name rowTextView.setText(m.getMeterName(i+1)); // set the hint of the ET to the last submitted reading rowEditText.setHint(m.getLastReadString(i+1)); // add the textview to the linearlayout rowEditText.setInputType(InputType.TYPE_CLASS_PHONE);//InputType.TYPE_NUMBER_FLAG_DECIMAL); tr.addView(rowTextView); tr.addView(rowEditText); myTLreads.addView(tr); // add a reference to the textView myTextViews[i] = rowTextView; myEditTexts[i] = rowEditText; } final Button submit = (Button) findViewById(R.id.submitReadings); // add a click listener to the button try { submit.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { Log.d(TAG, "Submit button clicked, Main activity"); preSubmitCheck(m.getAccNo(), m.getPostCode(), myEditTexts); // method to do HTML getting and sending } }); } catch (Exception e) { Log.d(TAG, "Exceptions (submit button)" + e.toString()); } }// end of InitialiseUI I don't need to do anything with these values until a button is clicked. Would it be easier if they were a ListView, i'm guessing I would still have the problem of saving them and retrieving them on rotation. If it helps I have an object m which is a string[][] I could temporarily somehow store them in

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  • Nonstatic conversion functions; Casting different types, e.g. DirectX vector to OpenGL vector

    - by Markus
    I am currently working on a game "engine" that needs to move values between a 3D engine, a physics engine and a scripting language. Since I need to apply vectors from the physics engine to 3D objects very often and want to be able to control both the 3D, as well as the physics objects through the scripting system, I need a mechanism to convert a vector of one type (e.g. vector3d<float>) to a vector of the other type (e.g. btVector3). Unfortunately I can make no assumptions on how the classes/structs are laid out, so a simple reinterpret_cast probably won't do. So the question is: Is there some sort of 'static'/non-member casting method to achieve basically this: vector3d<float> operator vector3d<float>(btVector3 vector) { // convert and return } btVector3 operator btVector3(vector3d<float> vector) { // convert and return } Right now this won't compile since casting operators need to be member methods. (error C2801: 'operator foo' must be a non-static member)

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  • What's the best way to call jQuery scripts, in HTML/PHP template, or seperate js file?

    - by j-man86
    StackOverflow is telling me this is a subjective question, but I think it's a matter of fact! I have a number of scripts that I'm using on different parts of my site. In terms of making fewer http requests, I know it's better to combine all of these scripts into one .js file. However, isn't a waste of time for a page to call a .js full of 10 or 15 different functions when it's only using one? The other method I am using is to use PHP conditional statements... <?php if( is_page() ) { > $(document).ready(function(){ ... }); <?php } ?> What's the best method or comination of these methods?

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  • Opinions on platform game actor/background collision resolving

    - by Kawa
    Imagine the following scenario: I have a level whose physical structure is built up from a collection of bounding rectangles, combined with prerendered bitmap backgrounds. My actors, including the player character, all have their own bounding rectangle. If an actor manages to get stuck inside a level block, partially or otherwise, it'll need to be shifted out again, so that it is flush against the block. The untested technique I thought up during bio break is as follows: If an actor's box is found to intersect a level box, determine where the centerpoints of each rect are. If the actor's center is higher than the level box's, move the actor so that the bottom of the actor's rect is flush with the top of the level's rect, and vice versa if it's lower. Then do a similar thing horizontally. Opinions on that? Suggestions on better methods? Actually, the bounding rects are XNA BoundingBlocks with their Z spanning from -1 to 1, but it's still 2D gameplay.

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  • Seam + hibernate + jsf on weblogic

    - by Kiva
    I'm making a little project with Seam, Hibernate and JSF. This project run on JBoss 5.1. My boss wants to deploy this project on WebLogic. I read on the seam documentation that seam and WebLogic don't work fine together. I would like to know if I can use Hibernate (with JPA) and JSF on WebLogic and what framework (struts, spring?) I can use to replace Seam. Edit: I read in the seam documentation (chapter 39, weblogic integration) and I find that: For several releases of Weblogic there has been an issue with how Weblogic generates stubs and compiles EJB's that use variable arguments in their methods. This is confirmed in the Weblogic 9.X and 10.0.MP1 versions. Unfortunately the 10.3 version only partially addresses the issue as detailed below. So, I want to know if other problems like this exist. Edit 2: I use Weblogic 10.3

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  • Unmanaged Struct Instance in Managed Class

    - by HeHasMoments
    Hi, I've got a fairly specific problem i've been struggling with for a couple of days. I'm using a native C++, one of the methods takes a ptr to a struct containing fixed size char arrays. e.g. struct userData { char data1[10]; char data2[10]; }; method: short AddItem(long id, userData* data); I'm trying to call to call this from Managed VC++ but I need to have an instance of userData I can keep hold of in my managed class. Can anyone help with how to achieve this? Thanks

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  • Dynamically adding a Button to a PlaceHolder in a DataGrid

    - by hrnt
    I have basically something like this: <asp:datagrid id="DGrid" runat="server" AutoGenerateColumns="false"> <asp:TemplateColumn HeaderText="Stuff"> <ItemTemplate> <asp:PlaceHolder id="PH" runat="server" /> </ItemTemplate> </asp:TemplateColumn> </asp:datagrid> I need to add a Button to the PlaceHolder depending on the values of the data I am binding. At the moment I am adding the Button after the data is bound in Page_Load. The problem is that the data binding methods are not called in postbacks, so the Button disappears when I click on it. Any suggestions on how to do this? Problem is that I need to know some attributes of the grid item to create the Button, so I cannot create it before the data has been bound.

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  • biginteger calculation problem

    - by murali
    I am using the following code but the parameters are not passed to the methods. BigInteger p = BigInteger.valueOf(0); BigInteger u1 = obj.bigi_calc(g1, l); In this g1,l are long values. The method is private BigInteger bigi_calc(long g1, long l){ BigInteger cal = BigInteger.valueOf(g1); BigInteger cal1= BigInteger.valueOf(l); for(BigInteger f = BigInteger.ONE;f.compareTo(cal1)>0;f=f.add(BigInteger.ONE)){ //BigInteger p= BigInteger.valueOf(0); p = cal.multiply(cal1); System.out.println("check p"+p); } // System.out.println("check p"+p); return p; } The elipse shows that it may be out of sync, but the parameters are not passed to the functions. Can you please help me to solve this problem?

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  • How do I catch the exception in windows application in c#?

    - by user291169
    Where should we catch exception • In Layer Boundary (UI-BLL & BLL-DAL) • In that methods where there is no interaction between Layers only some business logic present How do I write exception in Save/Delete where some DML statement executing? • What should I write in DAL end? • What should I write in BLL end? • What should I write in UI end? In Get/Load method How do we handle exception • What should I write in BLL end? • What should I write in UI end? Should I catch System exception?

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  • Receiving SQL Server events from a CLR function

    - by Pablo Lerner
    I wrote a CLR class with several methods, which are linked as functions in a SQL Server 2005 database. When several of these functions are used in scope of one transaction or connection, I need another one to be automatically executed to clean up some stuff, at the time of transaction or connection close (either time is good for now, later I will decide which is best). I figure that receiving events from another new CLR functions can do, but I don't know how to achieve that. Can anyone point me to information on modules, documents or whatever, that can help me understand how to receive transaction or connection closing events in a CLR class, or how to execute a particular function when these events occur?

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  • Setting many key/value pairs

    - by Andrew
    Hi, I'm working on a rake task which imports from a JSON feed into an ActiveRecord called Person. Person has quite a few attributes and rather than write lines of code for setting each attribute I'm trying different methods. The closest I've got is shown below. This works nicely as far as outputing to screen but when I check the values have actually been set on the ActiveRecord itself it's always nil. So it looks like I can't use .to_sym to solve my problem? Any suggestions? I should also mention that I'm just starting out with Ruby, have been doing quite a bit of Objective-c and now need to embrace the Interwebs :) http = Net::HTTP.new(url.host, url.port) http.read_timeout = 30 json = http.get(url.to_s).body parsed = JSON.parse(json) if parsed.has_key? 'code' updatePerson = Person.find_or_initialize_by_code(parsed['code']) puts updatePerson.code parsed.each do |key, value| puts "#{key} is #{value}" symkey = key.to_sym updatePerson[:symkey] = value.to_s updatePerson.save puts "#{key}....." # shows the current key puts updatePerson[:symkey] # shows the correct value puts updatePerson.first_name # a sample key, it's returning nil end

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