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  • Is it possible to create an Android Service that listens for hardware key presses?

    - by VoteBrian
    I'd like to run an Android background service that will act as a keylistener from the home screen or when the phone is asleep. Is this possible? From semi-related examples online, I put together the following service, but get the error, "onKeyDown is undefined for the type Service". Does this mean it can't be done without rewriting Launcher, or is there something obvious I'm missing? public class ServiceName extends Service { @Override public void onCreate() { //Stuff } public IBinder onBind(Intent intent) { //Stuff return null; } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if(event.getAction() == KeyEvent.ACTION_DOWN) { switch(keyCode) { case KeyEvent.KEYCODE_A: //Stuff return true; case KeyEvent.KEYCODE_B: //Stuff return true; //etc. } } return super.onKeyDown(keyCode, event); } } I realize Android defaults to the search bar when you type from the home screen, but this really is just for a very particular use. I don't really expect anyone but me to want this. I just think it'd be nice, for example, to use the camera button to wake the phone.

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  • anti-if campaign

    - by Andrew Siemer
    I recently ran against a very interesting site that expresses a very interesting idea - the anti-if campaign. You can see this here at www.antiifcampaign.com. I have to agree that complex nested IF statements are an absolute pain in the rear. I am currently on a project that up until very recently had some crazy nested IFs that scrolled to the right for quite a ways. We cured our issues in two ways - we used Windows Workflow Foundation to address routing (or workflow) concerns. And we are in the process of implementing all of our business rules utilizing ILOG Rules for .NET (recently purchased by IBM!!). This for the most part has cured our nested IF pains...but I find myself wondering how many people cure their pains in the manner that the good folks at the AntiIfCampaign suggest (see an example here) by creating numerous amounts of abstract classes to represent a given scenario that was originally covered by the nested IF. I wonder if another way to address the removal of this complexity might also be in using an IoC container such as StructureMap to move in and out of different bits of functionality. Either way... Question: Given a scenario where I have a nested complex IF or SWITCH statement that is used to evaluate a given type of thing (say evaluating an Enum) to determine how I want to handle the processing of that thing by enum type - what are some ways to do the same form of processing without using the IF or SWITCH hierarchical structure? public enum WidgetTypes { Type1, Type2, Type3, Type4 } ... WidgetTypes _myType = WidgetTypes.Type1; ... switch(_myType) { case WidgetTypes.Type1: //do something break; case WidgetTypes.Type2: //do something break; //etc... }

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  • algorithm - How to sort a 0/1 array with 2n/3 comparisons?

    - by Jackson Tale
    In Algorithm Design Manual, there is such an excise 4-26 Consider the problem of sorting a sequence of n 0’s and 1’s using comparisons. For each comparison of two values x and y, the algorithm learns which of x < y, x = y, or x y holds. (a) Give an algorithm to sort in n - 1 comparisons in the worst case. Show that your algorithm is optimal. (b) Give an algorithm to sort in 2n/3 comparisons in the average case (assuming each of the n inputs is 0 or 1 with equal probability). Show that your algorithm is optimal. For (a), I think it is fairly easy. I can choose a[n-1] as pivot, then do something like in quicksort partition, scan 0 to n - 2, find the middle point where left side is all 0 and right side is all 1, this take n - 1 comparisons. But for (b), I can't get a clue. It says "each of the n inputs is 0 or 1 with equal probability", so I guess I can assume the numbers of 0 and 1 equal? But how can I get a result which is related to 1/3? divide the whole array into 3 groups? Thanks

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  • c program pointer

    - by sandy101
    Hello , I am trying some programs in c face a problem with this program #include<stdio.h> int main() { int a=9,*x; float b=3.6,*y; char c='a',*z; printf("the value is %d\n",a); printf("the value is %f\n",b); printf("the value is %c\n",c); x=&a; y=&b; z=&c; printf("%u\n",a); printf("%u\n",b); printf("%u\n",c); x++; y++; z++; printf("%u\n",a); printf("%u\n",b); printf("%u\n",c); return 0; } can any one tell me what is the problem with this and i also want to know that when in the above case if the pointer value is incremented then will it over write the previous value address as suppose that the value we got in the above program (without the increment in the pointer value )is 65524 65520 65519 and after the increment the value of the pointer is 65526(as 2 increment for the int ) 65524(as 4 increment for the float ) 65520(as 1 increment for the char variable ) then if in that case will the new pointer address overwrite the content of the previous address and what value be contained at the new address ......plz help

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  • Abstracting the interpretation of MVC checkboxes values received by the FormsCollection object

    - by Simon_Weaver
    In ASP.NET MVC a checkbox is generated by the HtmlHelper code here: <%= Html.CheckBox("List_" + mailingList.Key, true) %> as this HTML: <input id="List_NEW_PRODUCTS" name="List_NEW_PRODUCTS" type="checkbox" value="true" /> <input name="List_NEW_PRODUCTS" type="hidden" value="false" /> In case you're wondering why is there an extra hidden field? - then read this. Its definitely a solution that makes you first think 'hmmmmm' but then you realize its a pretty elegant one. The problem I have is when I'm trying to parse the data on the backend. Well its not so much of a problem as a concern if anything in future were to change in the framework. If I'm using the built in binding everything is great - its all done for me. But in my case I'm dynamically generating checkboxes with unknown names and no corresponding properties in my model. So i end up having to write code like this : if (forms["List_RETAIL_NOTIFICATION"] == "true,false") { } or this: if (forms.GetValues("List_RETAIL_NOTIFICATION")[0] == "true") { } Both of which i still look at and cringe - especially since theres no guarantee this will always be the return value. I'm wondering if theres a way to access the layer of abstraction used by the model binders - or if I'm stuck with my controller 'knowing' this much about HTTP POST hacks. Yes I'm maybe being a little picky - but perhaps theres a better clever way using the model binders that I can employ to read dynamically created checkbox parameters. In addition i was hoping this this post might help others searcheing for : "true,false". Even though I knew why it does this I just forgot and it took me a little while to realize 'duh'. FYI: I tried another few things, and this is what I found : forms["List_RETAIL_NOTIFICATION"] evaluates to "true,false" forms.GetValues("List_RETAIL_NOTIFICATION")[0] evaluates to "true" (forms.GetValue("List_RETAIL_NOTIFICATION").RawValue as string[])[0] evaluates to "true" forms.GetValues("List_RETAIL_NOTIFICATION").FirstOrDefault() evaluates to "true"

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  • Suggestions on error handling of Win32 C++ code: AtlThrow vs. STL exceptions

    - by EmbeddedProg
    In writing Win32 C++ code, I'd appreciate some hints on how to handle errors of Win32 APIs. In particular, in case of a failure of a Win32 function call (e.g. MapViewOfFile), is it better to: use AtlThrowLastWin32 define a Win32Exception class derived from std::exception, with an added HRESULT data member to store the HRESULT corresponding to value returned by GetLastError? In this latter case, I could use the what() method to return a detailed error string (e.g. "MapViewOfFile call failed in MyClass::DoSomething() method."). What are the pros and cons of 1 vs. 2? Is there any other better option that I am missing? As a side note, if I'd like to localize the component I'm developing, how could I localize the exception what() string? I was thinking of building a table mapping the original English string returned by what() into a Unicode localized error string. Could anyone suggest a better approach? Thanks much for your insights and suggestions.

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  • Load random swf object with jquery

    - by Eggnog
    I'm working on a site that utilizes full screen background video. I have three flash videos I'd like to load into the page which would be displayed randomly on page refresh. I know you can achieve this through action script loading the movies into one main .swf, but I'm rubbish with Flash and am looking for an alternative solution. My search so far has uncovered a method using jquery. Unfortunately my attempts to implement it have failed. I'm hoping someone more knowledgeable than myself can tell me if this technique is valid or what I'm doing wrong. Here's my code to date: <script type="text/javascript" src="files/js/swfobject.js"></script> <script type="text/javascript"> $(document).ready(function() { var sPath; var i = Math.floor(Math.random()*2); switch(i) { case 0: sPath = "flash/homepage_video.swf"; break; case 1: sPath = "flash/homepage_video.swf"; break; } // load the flash version of the image var so = new SWFObject(sPath, "flash-background", "100%", "100%"); so.addParam("scale", "exactFit"); so.addParam("movie", sPath); // NOTE: the sPath variable is also used here so.addParam("quality", "high"); so.addParam("wmode", "transparent"); so.write("homeBackground"); // NOTE: The value in this call to write() MUST match the name of the // HTML element (<div>) you're expecting the swf to show up in }); </script> <body> <div id="homeBackground"> <p>This is alternative content</p> </div> </body> I'm open to other suggestions that don't involve jquery (php perhaps). Thanks.

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  • Lock-Free Data Structures in C++ Compare and Swap Routine

    - by slf
    In this paper: Lock-Free Data Structures (pdf) the following "Compare and Swap" fundamental is shown: template <class T> bool CAS(T* addr, T exp, T val) { if (*addr == exp) { *addr = val; return true; } return false; } And then says The entire procedure is atomic But how is that so? Is it not possible that some other actor could change the value of addr between the if and the assignment? In which case, assuming all code is using this CAS fundamental, it would be found the next time something "expected" it to be a certain way, and it wasn't. However, that doesn't change the fact that it could happen, in which case, is it still atomic? What about the other actor returning true, even when it's changes were overwritten by this actor? If that can't possibly happen, then why? I want to believe the author, so what am I missing here? I am thinking it must be obvious. My apologies in advance if this seems trivial.

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  • Do I need to write a trigger for such a simple constraint?

    - by Paul Hanbury
    I really had a hard time knowing what words to put into the title of my question, as I am not especially sure if there is a database pattern related to my problem. I will try to simplify matters as much as possible to get directly to the heart of the issue. Suppose I have some tables. The first one is a list of widget types: create table widget_types ( widget_type_id number(7,0) primary key, description varchar2(50) ); The next one contains icons: create table icons ( icon_id number(7,0) primary key, picture blob ); Even though the users get to select their preferred widget, there is a predefined subset of widgets that they can choose from for each widget type. create table icon_associations ( widget_type_id number(7,0) references widget_types, icon_id number(7,0) references icons, primary key (widget_type_id, icon_id) ); create table icon_prefs ( user_id number(7,0) references users, widget_type_id number(7,0), icon_id number(7,0), primary key (user_id, widget_type_id), foreign key (widget_type_id, icon_id) references icon_associations ); Pretty simple so far. Let us now assume that if we are displaying an icon to a user who has not set up his preferences, we choose one of the appropriate images associated with the current widget. I'd like to specify the preferred icon to display in such a case, and here's where I run into my problem: alter table icon_associations add ( is_preferred char(1) check( is_preferred in ('y','n') ) ) ; I do not see how I can enforce that for each widget_type there is one, and only one, row having is_preferred set to 'y'. I know that in MySQL, I am able to write a subquery in my check constraint to quickly resolve this issue. This is not possible with Oracle. Is my mistake that this column has no business being in the icon_associations table? If not where should it go? Is this a case where, in Oracle, the constraint can only be handled with a trigger? I ask only because I'd like to go the constraint route if at all possible. Thanks so much for your help, Paul

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  • Android Camera intent creating two files

    - by Kyle Ramstad
    I am making a program that takes a picture and then shows it's thumbnail. When using the emulator all goes well and the discard button deletes the photo. But on a real device the camera intent saves the image at the imageUri variable and a second one that is named like if I had just opened up the camera and took a picture by itself. private static final int CAMERA_PIC_REQUEST = 1337; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.camera); //start camera values = new ContentValues(); values.put(MediaStore.Images.Media.TITLE, "New Picture"); values.put(MediaStore.Images.Media.DESCRIPTION,"From your Camera"); imageUri = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values); image = (ImageView) findViewById(R.id.ImageView01); Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri); startActivityForResult(intent, CAMERA_PIC_REQUEST); //save the image buttons Button save = (Button) findViewById(R.id.Button01); Button close = (Button) findViewById(R.id.Button02); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (requestCode == CAMERA_PIC_REQUEST && resultCode == RESULT_OK) { try{ thumbnail = MediaStore.Images.Media.getBitmap(getContentResolver(), imageUri); image.setImageBitmap(thumbnail); } catch(Exception e){ e.printStackTrace(); } } else{ finish(); } } public void myClickHandler(View view) { switch (view.getId()) { case R.id.Button01: finish(); break; case R.id.Button02: dicard(); } } private void dicard(){ getContentResolver().delete(imageUri, null, null); finish(); }

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  • exit /B 0 does not work

    - by murxx
    I have the following problem: I have created a batch script which calls itself in there (for being able to write a log in parallel). In the script I start another process (like start startServer.bat) which starts up a java process and keeps opened up all the time. In my original script I wait 30 seconds, check if the process is running and do an: exit /B 0 Unfortunately that does not work, the window shows that the exit /B 0 is being evaluated, but the window still keeps open. When I close the window with the other process (meaning the "child" processes started up in my .bat) my script continues its run. So: scriptA.bat -> in there I call: start startServer.bat -> wait 30 seconds -> check is server is started -> exit /B 0 Process hangs up! What's very odd, if I wrap another script around, like: scriptB.bat -> call scriptA.bat -----> in there I call: start startServer.bat -----> wait 30 seconds -----> check if server is started -----> exit /B 0 -> scriptA.bat continues without any hangup! I also tried the same with exit 0 (without /B) also, same result! In the first case it hangs up, in the second case my window closes as expected... Has anyone of you ever had such a problem before and knows what's wrong here? Process hangs up!

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  • my dialog box did not show up whene i compile it using sdk 7.1,

    - by zirek
    hello and welcom everyone .. i'd like to build a win32 application using sdk 7.1, i create the dialog box using visual c++ 2012 resource editor, i copy resource.rc and resource.h to my folder and i write this simple main.cpp file: #include <windowsx.h> #include <Windows.h> #include <tchar.h> #include "resource.h" #define my_PROCESS_MESSAGE(hWnd, message, fn) \ case(message): \ return( \ SetDlgMsgResult(hWnd, uMsg, \ HANDLE_##message((hWnd), (wParam), (lParam), (fn)) )) \ LRESULT CALLBACK DlgProc(HWND, UINT, WPARAM, LPARAM); BOOL Cls_OnInitDialog(HWND hwnd, HWND hwndFocus, LPARAM lParam); void Cls_OnCommand(HWND hwnd, int id, HWND hwndCtl, UINT codeNotify); int WINAPI _tWinMain( HINSTANCE hInstance, HINSTANCE, LPTSTR, int iCmdLine ) { DialogBoxParam( hInstance, MAKEINTRESOURCE(IDD_INJECTOR), NULL, (DLGPROC) DlgProc, NULL ); return FALSE; } LRESULT CALLBACK DlgProc( HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam ) { switch (uMsg) { my_PROCESS_MESSAGE(hwnd, WM_INITDIALOG, Cls_OnInitDialog); my_PROCESS_MESSAGE(hwnd, WM_COMMAND, Cls_OnCommand); default: break; } return DefWindowProc(hwnd, uMsg, wParam, lParam); } BOOL Cls_OnInitDialog(HWND hwnd, HWND hwndFocus, LPARAM lParam) { return TRUE; } void Cls_OnCommand(HWND hwnd, int id, HWND hwndCtl, UINT codeNotify) { switch(id) { case IDCANCEL: EndDialog(hwnd, id); break; default: break; } } then i use the following command line to compile my code, wich i found on this forum cl main.cpp /link /SUBSYSTEM:WINDOWS user32.lib my problem is that my dialog box did not show up, and when i use procexp, to see what happen, i found that that my application is created then closed in the same time, and what make me wondering is that its working fine on visual c++ 2012. my sdk 7.1, installed correctly, i testing it against a basic window without any resource file any ideas, ill be really thankful Best, Zirek

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  • How to catch non exist requested URL in Java servlet ?

    - by Frank
    My objects are stored online in two different places : <1 On my nmjava.com site, where I can put them in a directory called "Dir_My_App/Dir_ABC/" <2 On Google App Engine datastore When my Java app runs it checks both places for the objects, I designed the app so that it tries to get an object from a Url, it doesn't care whether it's an object in a directory or an object returned by a servlet. My_Object Get_Object(String Site_Url,String Object_Path) { ... get object by the name of Object_Path from the Site_Url ... } Now the request Url for my web site nmjava.com might look like this : http://nmjava.com/Dir_My_App/Dir_ABC/My_Obj_123 [ In a directory ] Or in the case of Google App Engine servlet : http://nm-java.appspot.com/Check_License/Dir_My_App/Dir_ABC/My_Obj_123 [ Non exist ] The "Object_Path" was generated by my app automatically. It can now get the object from my site by the above method like this : My_Object Get_Object("http://nmjava.com","/Dir_My_App/Dir_ABC/My_Obj_123"); In the Google App Engine, my servlet is running and ready to serve the object, if the request comes in correctly, but since I don't want to design my app to know whether the object is in one site's directory or in other site's datastore, I need to design the servlet to catch the non exist Url, such as the one above, and be able to make a call : My_Object Get_Object("http://nm-java.appspot.com/Check_License","/Dir_My_App/Dir_ABC/My_Obj_123"); So my question is : When a request comes into the servlet with a non exist Url, how should it catch it and analyze the url in order to respond properly, in my case it should know that : http://nm-java.appspot.com/Check_License/Dir_My_App/Dir_ABC/My_Obj_123 is asking for the object "My_Obj_123" [ ignore the dirs ] and return the object from the datastore. Now I'm getting this : Error: Not Found The requested URL /Check_License/Dir_My_App/Dir_ABC/My_Obj_123 was not found on this server. Where in my servlet and how do I detect the request for this non exist Url ?

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  • BASIC Menu-driven program repeates twice after successful completion of first task.

    - by Zazu
    Hello, Im using Plato3 to write C programs. Im creating a menu-driven program but want to test out the basic concept of getting it to work #include<stdio.h> #include<ctype.h> int function1(); main(){ char s; do{ puts("\n choose the following"); puts("(P)rint\n"); puts("(Q)uit\n"); scanf("%c",&s); s=toupper(s); switch (s){ case 'P' : function1(); break; case 'Q' : return -1; break; } }while (function1()==0); } int function1(){ printf("Hello World"); return 0; } The problem is that once function1() returns the value 0, the whole program is echoed ... why ? Example : Running the program gives this : Hello WorldHellow World choose the following (P)rint (Q)uit Hello World choose the following (P)rint (Q)uit -- Any idea why ? Please help, thanks !!!!

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  • SVG rotation animation having problems on chrome for jelly bean, is there a workaround?

    - by Metalskin
    I've got a strange problem with chrome on jellybean running svg animations triggered from javascript. This JSFiddle example works fine on chrome and firefox on linux, but when I run it on android with chrome I get the final step of the animation painted at the beginning of the animation. I've tried this on both an Nexus 7 and Transformer Prime, they both have the problem. I've tested using firefox on the android devices and the problem doesn't exist. So I'm presuming that it's a defect with chrome. However I've seen other animations using svg that do not have this problem in chrome on jellybean. Is anyone aware of a way to get around this problem, or is there something that I'm doing in my animation/js that is a possible cause of the problem? I've now created a bug report at code.google.com, however I still need a workaround, if anyone can help me (or in case I'm doing something stupid). I've now discovered that this is reproducible on chrome for linux (and I suspect windows). If you click on the button to start the animation before the previous animation has completed then the problem occurs. In this case the hand is drawn at the end of the 45 degree sweep before it starts the sweep. I now suspect that I should be calling something to stop the animation before I change the animation. Anyway, hopefully someone can resolve this problem.

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  • Cocoa NSTextField Drag & Drop Requires Subclass... Really?

    - by ipmcc
    Until today, I've never had occasion to use anything other than an NSWindow itself as an NSDraggingDestination. When using a window as a one-size-fits-all drag destination, the NSWindow will pass those messages on to its delegate, allowing you to handle drops without subclassing NSWindow. The docs say: Although NSDraggingDestination is declared as an informal protocol, the NSWindow and NSView subclasses you create to adopt the protocol need only implement those methods that are pertinent. (The NSWindow and NSView classes provide private implementations for all of the methods.) Either a window object or its delegate may implement these methods; however, the delegate’s implementation takes precedence if there are implementations in both places. Today, I had a window with two NSTextFields on it, and I wanted them to have different drop behaviors, and I did not want to allow drops anywhere else in the window. The way I interpret the docs, it seems that I either have to subclass NSTextField, or make some giant spaghetti-conditional drop handlers on the window's delegate that hit-checks the draggingLocation against each view in order to select the different drop-area behaviors for each field. The centralized NSWindow-delegate-based drop handler approach seems like it would be onerous in any case where you had more than a small handful of drop destination views. Likewise, the subclassing approach seems onerous regardless of the case, because now the drop handling code lives in a view class, so once you accept the drop you've got to come up with some way to marshal the dropped data back to the model. The bindings docs warn you off of trying to drive bindings by setting the UI value programmatically. So now you're stuck working your way back around that too. So my question is: "Really!? Are those the only readily available options? Or am I missing something straightforward here?" Thanks.

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  • Error loading il8n console in CakePHP 1.3

    - by inkedmn
    I'm trying to generate the .po files for the site I'm working with. When I run this command from within the console directory: Warning: strtotime(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'America/Los_Angeles' for 'PDT/-7.0/DST' instead in /Users/bkelly/Development/[redacted]/www/trunk/about/trunk/cake/libs/cache.php on line 570 Warning: strtotime(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'America/Los_Angeles' for 'PDT/-7.0/DST' instead in /Users/bkelly/Development/[redacted]/www/trunk/about/trunk/cake/libs/cache.php on line 570 Error: Class Il8nShell could not be loaded. This also happens if I issue ./cake il8n help . The bake console seems to load fine (no errors, takes me to the expected menu). I'm running CakePHP 1.3.0 under Mac OSX 10.6 (using MAMP). Cake appears to be functioning normally otherwise. Thanks!

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  • Capacity Allocation

    - by user1708730
    I am new to VB in Excel. I have a unique requirement for capacity allocation which I want to automate using excel VB and facing hard time doing so, hope you can help. The objective is to maximize profit by allocating maximum capacity to those products which have highest profit potential first. Every Month I get demand along with backlogs of previous month. I need to allocate capacity to backlogs of previous month first and then only the remaining capacity for fresh demand. There are two primary constraints: 1.The number of working days in a month (variable) 2. Not all products can be made on every production line and out of same product may be different for each production line Also there will be losses whenever there is a change over from one SKU to another depending upon the Variant Type and size of next product. If there is variant change then 8 hours of production loss needs to be accounted and 4 hours in case of size change(8 hours in case of both). I have attached sample data(Actual data has 10 production lines and 50 products) https://rapidshare.com/files/1822719405/Sample%20Data.xlsx?bin=1 Thanks in advance for help!

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  • Best way to implement plugin framework - are DLLs the only way (C/C++ project)?

    - by Microkernel
    Introduction: I am currently developing a document classifier software in C/C++ and I will be using Naive-Bayesian model for classification. But I wanted the users to use any algorithm that they want(or I want in the future), hence I went to separate the algorithm part in the architecture as a plugin that will be attached to the main app @ app start-up. Hence any user can write his own algorithm as a plugin and use it with my app. Problem Statement: The way I am intending to develop this is to have each of the algorithms that user wants to use to be made into a DLL file and put into a specific directory. And at the start, my app will search for all the DLLs in that directory and load them. My Questions: (1) What if a malicious code is made as a DLL (and that will have same functions mandated by plugin framework) and put into my plugins directory? In that case, my app will think that its a plugin and picks it and calls its functions, so the malicious code can easily bring down my entire app down (In the worst case could make my app as a malicious code launcher!!!). (2) Is using DLLs the only way available to implement plugin design pattern? (Not only for the fear of malicious plugin, but its a generic question out of curiosity :) ) (3) I think a lot of softwares are written with plugin model for extendability, if so, how do they defend against such attacks? (4) In general what do you think about my decision to use plugin model for extendability (do you think I should look at any other alternatives?) Thank you -MicroKernel :)

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  • JPA entitylisteners and @embeddable

    - by seanizer
    I have a class hierarchy of JPA entities that all inherit from a BaseEntity class: @MappedSuperclass @EntityListeners( { ValidatorListener.class }) public abstract class BaseEntity implements Serializable { // other stuff } I want all entities that implement a given interface to be validated automatically on persist and/or update. Here's what I've got. My ValidatorListener: public class ValidatorListener { private enum Type { PERSIST, UPDATE } @PrePersist public void checkPersist(final Object entity) { if (entity instanceof Validateable) { this.check((Validateable) entity, Type.PERSIST); } } @PreUpdate public void checkUpdate(final Object entity) { if (entity instanceof Validateable) { this.check((Validateable) entity, Type.UPDATE); } } private void check(final Validateable entity, final Type persist) { switch (persist) { case PERSIST: if (entity instanceof Persist) { ((Persist) entity).persist(); } if (entity instanceof PersistOrUpdate) { ((PersistOrUpdate) entity).persistOrUpdate(); } break; case UPDATE: if (entity instanceof Update) { ((Update) entity).update(); } if (entity instanceof PersistOrUpdate) { ((PersistOrUpdate) entity).persistOrUpdate(); } break; default: break; } } } and here's my Validateable interface that it checks against (the outer interface is just a marker, the inner contain the methods): public interface Validateable { interface Persist extends Validateable { void persist(); } interface PersistOrUpdate extends Validateable { void persistOrUpdate(); } interface Update extends Validateable { void update(); } } All of this works, however I would like to extend this behavior to Embeddable classes. I know two solutions: call the validation method of the embeddable object manually from the entity validation method: public void persistOrUpdate(){ // validate my own properties first // then manually validate the embeddable property: myEmbeddable.persistOrUpdate(); // this works but I'd like something that I don't have to call manually } use reflection, checking all properties to see if their type is of one of their interface types. This would work, but it's not pretty. Is there a more elegant solution?

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  • Solr : how do i index and search several fields?

    - by sbrattla
    Hi, I've set up my first 'installation' of Solr, where each index (document) represents a musical work (with properties like number (int), title (string), version (string), composers (string) and keywords (string)). I've set the field 'title' as the default search field. However, what do I do when I would like to do a query on all fields? I'd like to give users the opportunity to search in all fields, and as far as I've understood there is at least two options for this: (1) Specify which fields the query should be made against. (2) Set up the Solr configuration with copyfields, so that values added to each of the fields will be copied to a 'catch-all'-like field which can be used for searching. However, in this case, i am uncertain how things would turn out when i take into consideration that the data types are not all the same for the various fields (the various fields will to a lesser og greater degree go through filters, but as copyfield values are taken from their original fields before the values have been run through their original fields' filters, i would have to apply one single filter to all values on the copyfield. This, again, would result in integers being 'filtered' just as strings would). Is this a case where i should use copyfields? At first glance, it seems a bit more 'flexible' to rather just search on all fields. However, maybe there's a cost? All feedback appreciated! Thanks!

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  • Delphi: Transporting Objects to remote computers

    - by pr0wl
    Hallo. I am writing a tier2 ordering software for network usage. So we have client and server. On the client I create Objects of TBest in which the Product ID, the amount and the user who orders it are saved. (So this is a item of an Order). An order can have multiple items and those are saved in an array to later send the created order to the server. The class that holds the array is called TBestellung. So i created both TBest.toString: string; and TBest.fromString(source: string): TBest; Now, I send the toString result to the server via socket and on the server I create the object using fromString (its parsing the attributes received). This works as intended. Question: Is there a better and more elegant way to do that? Serialisation is a keyword, yes, but isn't that awful / difficult when you serialize an object (TBestellung in this case) that contains an Array of other Objects (TBest in this case)? //Small amendment: Before it gets asked. Yes I should create an extra (static) class for toString and fromString because otherwise the server needs to create an "empty" TBest in order to be able to use fromString.

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  • C++ socket protocol design issue (ring inclusion)

    - by Martin Lauridsen
    So I have these two classes, mpqs_client and client_protocol. The mpqs_client class handles a Boost socket connection to a server (sending and receiving messages with some specific format. Upon receiving a message, it calls a static method, parse_message(..), in the class client_protocol, and this method should analyse the message received and perform some corresponding action. Given some specific input, the parse_message method needs to send some data back to the server. As mentioned, this happens through the class mpqs_client. So I could, from mpqs_client, pass "this" to parse_message(..) in client_protocol. However, this leads to a two-way association relationship between the two classes. Something which I reckon is not desireable. Also, to implement this, I would need to include the other in each one, and this gives me a terrible pain. I am thinking this is more of a design issue. What is the best solution here? Code is posted below. Class mpqs_client: #include "mpqs_client.h" mpqs_client::mpqs_client(boost::asio::io_service& io_service, tcp::resolver::iterator endpoint_iterator) : io_service_(io_service), socket_(io_service) { ... } ... void mpqs_client::write(const network_message& msg) { io_service_.post(boost::bind(&mpqs_client::do_write, this, msg)); } Class client_protocol: #include "../network_message.hpp" #include "../protocol_consts.h" class client_protocol { public: static void parse_message(network_message& msg, mpqs_sieve **instance_, mpqs_client &client_) { ... switch (type) { case MPQS_DATA: ... break; case POLYNOMIAL_DATA: ... break; default: break; } }

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  • JPA - Real primary key generated ID for references

    - by Val
    I have ~10 classes, each of them, have composite key, consist of 2-4 values. 1 of the classes is a main one (let's call it "Center") and related to other as one-to-one or one-to-many. Thinking about correct way of describing this in JPA I think I need to describe all the primary keys using @Embedded / @PrimaryKey annotations. Question #1: My concern is - does it mean that on the database level I will have # of additional columns in each table referring to the "Center" equal to number of column in "Center" PK? If yes, is it possible to avoid it by using some artificial unique key for references? Could you please give an idea how real PK and the artificial one needs to be described in this case? Note: The reason why I would like to keep the real PK and not just use the unique id as PK is - my application have some data loading functionality from external data sources and sometimes they may return records which I already have in local database. If unique ID will be used as PK - for new records I won't be able to do data update, since the unique ID will not be available for just downloaded ones. At the same time it is normal case scenario for application and it just need to update of insert new records depends on if the real composite primary key matches. Question #2: All of the 10 classes have common field "date" which I described in an abstract class which each of them extends. The "date" itself is never a key, but it always a part of composite key for each class. Composite key is different for each class. To be able to use this field as a part of PK should I describe it in each class or is there any way to use it as is? I experimented with @Embedded and @PrimaryKey annotations and always got an error that eclipselink can't find field described in an abstract class. Thank you in advance! PS. I'm using latest version of eclipselink & H2 database.

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  • App crashes frequently at time when UIActionSheet would be presented

    - by Jim Hankins
    I am getting the following error intermittently when a call is made to display an action sheet. Assertion failure in -[UIActionSheet showInView:] Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid parameter not satisfying: view != nil' Now in this case I've not changed screens. The UIActionSheet is presented when a local notification is fired and I have an observer call a local method on this view as such: I have the property marked as strong. When the action sheet is dismissed I also set it to nil. I am using a story board for the UI. It's fairly repeatable to crash it, perhaps less than 5 tries. (Thankfully I have that going for me). Any suggestions what to try next? I'm really pulling my hair out on this one. Most of the issues I've seen on this topic are pointing to the crash occurring once the selection is made. In my case it's at presentation and intermittently. Also for what it's worth, this particular view is several stacks deep in an embedded navigation controller. Hometableviewdetail selectviewController in question. This same issue occurs so far in testing on iOS 5.1 and iOS 6. I'm presuming it's something to do with how the show InView is being targeted. self.actionSheet = [[UIActionSheet alloc] initWithTitle:@"Select Choice" delegate:self cancelButtonTitle:@"Not Yet" destructiveButtonTitle:@"Do this Now" otherButtonTitles:nil]; [self.actionSheet showInView:self.parentViewController.tabBarController.view];

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