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  • Strange casting problem with tm structure

    - by egiakoum1984
    I have the following casting problem when my data structure sSpecificData contains a field of type tm: typedef struct { unsigned char data[10000]; } sDataBuffer; typedef struct { int m_Id; sDataBuffer m_Data; } sData; typedef struct { int m_value1; int m_value2; tm m_Date; } sSpecificData; const int SPECIFIC_SVC_DATA_SIZE = sizeof(sSpecificData); typedef struct { int m_Id; sSpecificData m_Data; } sMyData; int main(void) { sData svc; sMyData* ptr1 = (sMyData*) &svc; sSpecificData* ptr2; ptr2 = (sSpecificData*) &svc.m_Data; ptr1->m_Data.m_value1 = 90; ptr1->m_Data.m_value2 = 80; cout << ptr1->m_Data.m_value1 << endl; cout << ptr1->m_Data.m_value2 << endl; cout << ptr2->m_value1 << endl; cout << ptr2->m_value2 << endl; return 0; } Without the field "tm m_Date;" as part of the sSpecificData, the output is correct: 90 80 90 80 With the field "tm m_Date;" as part of the sSpecificData, the output is wrong: 90 80 0 <-- ! 90 <-- ! Is there any idea why my example doesn't work when there is field of type tm as part of the sSpecificData? Thanks!

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  • Passing Object to Service in WCF

    - by hgulyan
    Hi, I have my custom class Customer with its properties. I added DataContract mark above the class and DataMember to properties and it was working fine, but I'm calling a service class's function, passing customer instance as parameter and some of my properties get 0 values. While debugging I can see my properties values and after it gets to the function, some properties' values are 0. Why it can be so? There's no code between this two actions. DataContract mark workes fine, everything's ok. Any suggestions on this issue? I tried to change ByRef to ByVal, but it doesn't change anything. Why it would pass other values right and some of integer types just 0? Maybe the answer is simple, but I can't figure it out. Thank You. <DataContract()> Public Class Customer Private Type_of_clientField As Integer = -1 <DataMember(Order:=1)> Public Property type_of_client() As Integer Get Return Type_of_clientField End Get Set(ByVal value As Integer) Type_of_clientField = value End Set End Property End Class <ServiceContract(SessionMode:=SessionMode.Allowed)> <DataContractFormat()> Public Interface CustomerService <OperationContract()> Function addCustomer(ByRef customer As Customer) As Long End Interface type_of_client properties value is 6 before I call addCustomer function. After it enters that function the value is 0. UPDATE: The issue is in instance creating. When I create an instance of a class on client side, that is stored on service side, some of my properties pass 0 or nothing, but when I call a function of a service class, that returns a new instance of that class, it works fine. What's is the difference? Could that be serialization issue?

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  • How to copy an array of char pointers with a larger list of char pointers?

    - by Casey Link
    My function is being passed a struct containing, among other things, a NULL terminated array of pointers to words making up a command with arguments. I'm performing a glob match on the list of arguments, to expand them into a full list of files, then I want to replace the passed argument array with the new expanded one. The globbing is working fine, that is, g.gl_pathv is populated with the list of expected files. However, I am having trouble copying this array into the struct I was given. #include <glob.h> struct command { char **argv; // other fields... } void myFunction( struct command * cmd ) { char **p = cmd->argv; char* program = *p++; // save the program name (e.g 'ls', and increment to the first argument glob_t g; memset(&g, 0, sizeof(g)); int res = glob(*p, 0, NULL, &g); *p++ // increment while (*p) { glob(*p++, GLOB_APPEND, NULL, &g); // append the matches } // here i want to replace cmd->argv with the expanded g.gl_pathv memcpy(cmd->argv, g.gl_pathv, g.gl_pathc ); // this doesn't work globfree(&g); }

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  • Spring MVC handle button event in list

    - by GigaPr
    Hi, i created a list of Users <div class="usersList"> <c:forEach items="${users}" var="user"> <div class="listElementAction"> <c:out value="${user.id}"/> </div> <div class="listElement"> <c:out value="${user.firstName}"/> </div> <div class="listElement"> <c:out value="${user.lastName}"/> </div> <div class="listElement"> <c:out value="${user.username}"/> </div> <div class="listElementAction"> <input type="button" name="Edit" title="Edit" value="Edit" /> </div> <div class="listElementAction"> <input type="image" src="images/delete.png" name="image" value="${user.id}" alt="Delete" onclick="return confirm('Do you want to delete ${user.username}?')" > </div> <br /> </c:forEach> </div> and my controler looks like this public class UsersController implements Controller { private UserServiceImplementation userServiceImplementation; public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ModelAndView modelAndView = new ModelAndView("users"); modelAndView.addObject("users", this.userServiceImplementation.get()); return modelAndView; } public UserServiceImplementation getUserServiceImplementation() { return userServiceImplementation; } public void setUserServiceImplementation(UserServiceImplementation userServiceImplementation) { this.userServiceImplementation = userServiceImplementation; } } How can i handle the delete and edit button event?

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  • PHP regex - find and replace

    - by jay
    Hi, I am trying to do this regex match and replace but not able to do it. Example <SPAN class="one">first content here</SPAN> <SPAN class="two">second content here </SPAN> <SPAN class="three">one; two; three; and more.</span> <SPAN class="four">more content here.</span> I want to find each set of the span tags and replace with something like this Find <SPAN class="one">first content here</SPAN> Change to <one>first content here</one> same way the the rest of the span tags. class="one", class="two" and so on are the only key identifier which I use in the regex match expression. So if I find a span tag with these class then I want to do the replace. My main issue is that I am not able to find the occurrence of first closing tag so what it does is it finds from the start to end which is of no use. So far I have been trying to do this using notepad++ but just found that it has its limitations so any php help would be appreciated. regards

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  • WPF and events from dynamically created controls

    - by OKB
    Hi, I need some help to implement a common behavior in some controls. In my WPF application, I have a main form that contains a panel and a button: Ok The button will run a Save method when clicked.The Save method reads some data from the form and saves the data to a database. The panel is populated with dynamically created controls (such as textbox, dropdownlists, etc). The main form instantiates a MainViewModel class. This MainViewModel class instantiates a class called UIFactory. So we have 3 levels here. In the UIFactory class the controls is being created. The Panel from the main form is sent as a parameter to a method in the MainModelView class called GenerateUI. This GenerateUI method in the MainViewModel class calls a GenerateControls method on the UIFactory class that takes the same panel as a parameter. The GenerateControls method in the UIFactory class then adds dynamically created controls on the panel. What I want to achieve is that whenever the user hits ENTER when he is typing in one of those dynamically created controls e.g a textbox, I want that behavior to be the same as clicking on the button in my main form. But how do I do that? I thought of implementing Routed events on my controls, but I can't figure out how to do it. Could you please advise me on how to achieve my goal? Best Regards, OKB

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  • Discriminator based on joined property

    - by Andrew
    Suppose I have this relationship: abstract class Base { int Id; int JoinedId; ... } class Joined { int Id; int Discriminator; ... } class Sub1 : Base { ... } class Sub2 : Base { ... } for the following tables: table Base ( Id int, JoinedId int, ... ) table Joined ( Id int, Discriminator int, ... ) I would like to set up a table-per-hierarchy inheritance mapping for the Base, Sub1, Sub2 relationships, but using the Disciminator property from the Joined class as the discriminator. Here's the general idea for the mapping file: <class name="Base" table="Base"> <id name="Id"><generator class="identity"/></id> <discriminator /> <!-- ??? or <join> or <many-to-one>? --> <subclass name="Sub1" discriminator-value="1">...</subclass> <subclass name="Sub2" discriminator-value="2">...</subclass> </class> Is there any way of accomplishing something like this with the <discriminator>, <join>, or <many-to-one>? NHiberante seems to assume the discriminator is a column on the given table (which makes sense to me.. I know this is unorthodox). Thanks.

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  • APC values randomly disappear

    - by Michael
    I'm using APC for storing a map of class names to class file paths. I build the map like this in my autoload function: $class_paths = apc_fetch('class_paths'); // If the class path is stored in application cache - search finished. if (isset($class_paths[$class])) { return require_once $class_paths[$class]; // Otherwise search in known places } else { // List of places to look for class $paths = array( '/src/', '/modules/', '/libs/', ); // Search directories and store path in cache if found. foreach ($paths as $path) { $file = DOC_ROOT . $path . $class . '.php'; if (file_exists($file)) { echo 'File was found in => ' . $file . '<br />'; $class_paths[$class] = $file; apc_store('class_paths', $class_paths); return require_once $file; } } } I can see as more and more classes are loaded, they are added to the map, but at some point the apc_fetch returns NULL in the middle of a page request, instead of returning the map. Getting => class_paths Array ( [MCS\CMS\Helper\LayoutHelper] => /Users/mbl/Documents/Projects/mcs_ibob/core/trunk/src/MCS/CMS/Helper/LayoutHelper.php [MCS\CMS\Model\Spot] => /Users/mbl/Documents/Projects/mcs_ibob/core/trunk/src/MCS/CMS/Model/Spot.php ) Getting => class_paths {null} Many times the cached value will also be gone between page requests. What could be the reason for this? I'm using APC as an extension (PECL) running PHP 5.3.

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  • jquery child selector problems

    - by codedude
    I have a basic website nav layout that looks like this: <li class="folder parent_folder"> <a href="#">Some Folder</a> <ul class="submenu"> <li class="file"><a href="#">An awesome file</a></li> <li class="file"><a href="#">An awesome file</a></li> <li class="file"><a href="#">An awesome file</a></li> <li class="file"><a href="#">An awesome file</a></li> <li class="file"><a href="#">An awesome file</a></li> <li class="file"><a href="#">An awesome file</a></li> </ul> I have several of these throughout the site's page. Using jquery, I'm trying to make it so that when you click "li.parent_folder" "ul.submenu" disappears and then reappears when you click "li.parent_folder" again. I can get it to do this but I have a problem. When I click on the "li.parent_folder" all the "ul.submenu" disapear instead of just the one that is the child of it. What would be the correct jquery code to accomplish this? (Oh, I'm using jquery ui also in this project What I have right now is this: $('li.parent_folder').click(function() { $('li.parent_folder ul.submenu').hide(); });

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  • seg fault at the end of program after executing everything?

    - by Fantastic Fourier
    Hello all, I wrote a quick program which executes every statement before giving a seg fault error. struct foo { int cat; int * dog; }; void bar (void * arg) { printf("o hello bar\n"); struct foo * food = (struct foo *) arg; printf("cat meows %i\n", food->cat); printf("dog barks %i\n", *(food->dog)); } void main() { int cat = 4; int * dog; dog = &cat; printf("cat meows %i\n", cat); printf("dog barks %i\n", *dog); struct foo * food; food->cat = cat; food->dog = dog; printf("cat meows %i\n", food->cat); printf("dog barks %i\n", *(food->dog)); printf("time for foo!\n"); bar(food); printf("begone!\n"); cat = 5; printf("cat meows %i\n", cat); printf("dog barks %i\n", *dog); // return 0; } which gives a result of cat meows 4 dog barks 4 cat meows 4 dog barks 4 time for foo! o hello bar cat meows 4 dog barks 4 begone! cat meows 5 dog barks 5 Segmentation fault (core dumped) I'm not really sure why it seg faults at the end? Any comments/insights are deeply appreciated.

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  • Common lisp, CFFI, and instantiating c structs

    - by andrew
    Hi, I've been on google for about, oh, 3 hours looking for a solution to this "problem." I'm trying to figure out how to instantiate a C structure in lisp using CFFI. I have a struct in c: struct cpVect{cpFloat x,y;} Simple right? I have auto-generated CFFI bindings (swig, I think) to this struct: (cffi:defcstruct #.(chipmunk-lispify "cpVect" 'classname) (#.(chipmunk-lispify "x" 'slotname) :double) (#.(chipmunk-lispify "y" 'slotname) :double)) This generates a struct "VECT" with slots :X and :Y, which foreign-slot-names confirms (please note that I neither generated the bindings or programmed the C library (chipmunk physics), but the actual functions are being called from lisp just fine). I've searched far and wide, and maybe I've seen it 100 times and glossed over it, but I cannot figure out how to create a instance of cpVect in lisp to use in other functions. Note the function: cpShape *cpPolyShapeNew(cpBody *body, int numVerts, cpVect *verts, cpVect offset) Takes not only a cpVect, but also a pointer to a set of cpVects, which brings me to my second question: how do I create a pointer to a set of structs? I've been to http://common-lisp.net/project/cffi/manual/html_node/defcstruct.html and tried the code, but get "Error: Unbound variable: PTR" (I'm in Clozure CL), not to mention that looks to only return a pointer, not an instance. I'm new to lisp, been going pretty strong so far, but this is the first real problem I've hit that I can't figure out. Thanks!

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  • XmlAttribute/XmlText cannot be used to encode complex type

    - by Conrad C
    I want to serialize a class Ticket into xml. I get the error :"XmlAttribute/XmlText cannot be used to encode complex type" because of my customfield class. This is how the xml for customfields should look like ( the attribute array is nesseray but I don't understand how to create it): <custom_fields type="array"> <custom_field name="Standby Reason" id="6"> <value/> </custom_field> <custom_field name="Close Date" id="84"> Class Ticket public class Ticket { [XmlElement("custom_fields")] public CustomFields Custom_fields { get; set; } Class CustomFields [Serializable] public class CustomFields { [XmlAttribute("array")] public List<CustomField> custom_field { get; set; } Class CustomField [Serializable] public class CustomField { [XmlIgnore] public string Name { get; set; } [XmlElement] public int Id { get; set; } [XmlElement] public string Value { get; set; }

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  • compiling and running java on windows

    - by artur grzesiak
    I thought the task should be fairly easy, but my understanding of javac and java in general is rather poor. I am using Windows8 and would like to compile a single file.java that makes use of other classes. I successfully (at least without any warnings) compiled my file by calling: javac -cp relative_path_to_needed_classes relative_path_to_file_java\file.java Now if I want to run the result of compilation (file.class) by calling: java -cp relative_path_to_needed_classes relative_path_to_file_java\file I get: Error: Could not find or load main class relative_path_to_file_java\file I was trying a lot of combination to modify the -cp (eg. by adding .\;relative_path_to_file;) but still the closest where I get is: Exception in thread "main" java.lang.NoClassDefFoundError : relative_path_to_file\file (wrong name: file) The file from (wrong name: file) is the name of the file and the name of the public class within the file. I was reading a lot on SO and other sources but could not figure out what is wrong. Btw. as a result of compilation some other classes were created: file$1.class file$name1.class file$name2.class (where name1 and name2 are names of private classes within file.java) My questions are: What is (the most) probably source of my error / what am I doing wrong? What is the purpose of file$1.class? What is the minimum I should specify in -cp? May encoding play any role? Do every java class have to reside in a package? (rather not directly related to my issue) Do order of paths specified in -cp play any role in runtime?

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  • libpcap read packet size

    - by spicyramen
    I started to write an application which will read RTP/H.264 video packets from an existing .pcap file, I need to read the packet size. I tried to use packet-len or header-len, but it never displays the right number of bytes for packets (I'm using wireshark to verify packet size - under Length column). How to do it? This is part of my code: while (packet = pcap_next(handle,&header)) { u_char *pkt_ptr = (u_char *)packet; struct ip *ip_hdr = (struct ip *)pkt_ptr; //point to an IP header structure struct pcap_pkthdr *pkt_hdr =(struct pcap_pkthdr *)packet; unsigned int packet_length = pkt_hdr->len; unsigned int ip_length = ntohs(ip_hdr->ip_len); printf("Packet # %i IP Header length: %d bytes, Packet length: %d bytes\n",pkt_counter,ip_length,packet_length); Packet # 0 IP Header length: 180 bytes, Packet length: 104857664 bytes Packet # 1 IP Header length: 52 bytes, Packet length: 104857600 bytes Packet # 2 IP Header length: 100 bytes, Packet length: 104857600 bytes Packet # 3 IP Header length: 100 bytes, Packet length: 104857664 bytes Packet # 4 IP Header length: 52 bytes, Packet length: 104857600 bytes Packet # 5 IP Header length: 100 bytes, Packet length: 104857600 bytes Another option I tried is to use: pkt_ptr- I get: read_pcapfile.c:67:43: error: request for member ‘len’ in something not a structure or union

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  • JUnit confusion: use 'extend Testcase' or '@Test' ?

    - by Rabarberski
    I've found the proper use (or at least the documentation) of JUnit very confusing. This question serves both as a future reference and as a real question. If I've understood correctly, there are two main approaches to create and run a JUnit test: Approach A: create a class that extends TestCase, and start test methods with the word test. When running the class as a JUnit Test (in Eclipse), all methods starting with the word test are automatically run. import junit.framework.TestCase; public class DummyTestA extends TestCase { public void testSum() { int a = 5; int b = 10; int result = a + b; assertEquals(15, result); } } Approach B: create a 'normal' class and prepend a @Test annotation to the method. Note that you do NOT have to start the method with the word test. import org.junit.*; import static org.junit.Assert.*; public class DummyTestB { @Test public void Sum() { int a = 5; int b = 10; int result = a + b; assertEquals(15, result); } } Mixing the two seems not to be a good idea, see e.g. this stackoverflow question: Now, my questions(s): What is the preferred approach, or when would you use one instead of the other? Approach B allows for testing for exceptions by extending the @Test annotation like in @Test(expected = ArithmeticException.class). But how do you test for exceptions when using approach A? When using approach A, you can group a number of test classes in a test suite. TestSuite suite = new TestSuite("All tests");<br/> suite.addTestSuite(DummyTestA.class); suite.addTestSuite(DummyTestAbis.class);` But this can't be used with approach B (since each testclass should subclass TestCase). What is the proper way to group tests for approach B?

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  • Diamond problem in C++

    - by Jack
    I know the diamond problem. I am using gcc compiler. I have some scenarios I need explanation about. 1) class A{ public: virtual void eat(){cout<<"A eat\n";} }; class B:public A{ public: void eat(){ cout<<"B eat\n";}}; class C:public A{ public: void eat(){ cout<<"C eat\n";}}; class D:public B,C{ public: void eat(){ cout<<"D eat\n";}}; int main() { A * a = new D(); a->eat(); getch(); return 0; } Why doesn't this work? 2) class A{ public: void eat(){cout<<"A eat\n";} }; class B:virtual public A{ public: void eat(){ cout<<"B eat\n";}}; class C:virtual public A{ public: void eat(){ cout<<"C eat\n";}}; class D: public B,C{ public: void eat(){ cout<<"D eat\n";}}; int main() { A * a = new D(); a->eat(); getch(); return 0; } When I do this what happens in the background. How does the ambiguity get removed. Is the concept of vtables involved here?

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  • the error in the stringbuilder

    - by Kubi
    string rowString = "<tr id=\"row1\" bgcolor=\"#FFFFFF\" onMouseOver=\"this.bgColor='#EEEEEE';\" onMouseOut=\"this.bgColor='#FFFFFF';\" style=\"cursor:pointer;\">" + "<td bgcolor=\"#FFFFFF\"><img src=\"images/"+"-companylogofilename-"+"\" width=\"108\" height=\"32\" alt=\""+"-companyname-"+"\" /></td>" + //turkish.airlines.jpg airlineiconfilename, airline name "<td class=\"table_content\">{0}</td>" + "<td class=\"table_content\">{1}</td>" + "<td class=\"table_content\">{2}</td>" + "<td class=\"table_content\">{3}</td>" + "<td class=\"table_content\">{4}</td>" + "<td class=\"table_content\"><table width=\"98%\" border=\"0\" cellspacing=\"0\" cellpadding=\"0\">" + "<tr><td class=\"table_content\">{5}</td>" + "<td width=\"20\" align=\"right\">" + "<a href=\"default.aspx\" onClick=\"return hs.htmlExpand(this, { headingText: '{6} - {7}', width: 600, height: 215, targetX: 'row1 400px', targetY: 'row1 40px' })\">" + "<img src=\"images/arrow.png\" width=\"13\" height=\"16\" border=\"0\" class=\"tip\" onMouseOver=\"tooltip('Click for Details.');\" onMouseOut=\"exit();\" />" + "</a>"; accordionHTML.Append(String.Format(rowString, flight.Get_AirlineCode(), flight.Get_Clase(), flight.Get_Departure(), flight.Get_DeprtDate(), flight.Get_DeprtTime(), flight.Get_Destination(), flight.Get_Departure(), flight.Get_Destination())); Hi, Can someone please help me to find the mistake above ? I am getting an error as "Input string was not correct !"; Thanks in advance,

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  • Question about passing data using intents

    - by Joe K 1973
    Hi everyone, I'm trying to modify the Notepad tutorial (the Notepadv3 solution) to take in a value into the NoteEdit class, given to by the Notepadv3 class. I've successfully used .putExtra in the OnListItemClick method to place the value into the NoteEdit class, but I'm struggling to do this for the createNote method; I'm getting a force close when I try to create a new note. I bet there's a simple solution, but I'm pretty new to Java & Android and would very much appreciate your help. Here's the code in question in the Notepadv3 class: private void createNote() { Intent i = new Intent(this, NoteEdit.class); i.putExtra("key", 1); startActivityForResult(i, ACTIVITY_CREATE); } @Override protected void onListItemClick(ListView l, View v, int position, long id) { super.onListItemClick(l, v, position, id); Intent i = new Intent(this, NoteEdit.class); i.putExtra(NotesDbAdapter.KEY_ROWID, id); i.putExtra("key", 1); startActivityForResult(i, ACTIVITY_EDIT); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent intent) { super.onActivityResult(requestCode, resultCode, intent); fillData(); } And here's the receiving code in the NoteEdit class: mRowId = savedInstanceState != null ? savedInstanceState.getLong(NotesDbAdapter.KEY_ROWID) : null; if (mRowId == null) { Bundle extras = getIntent().getExtras(); mRowId = extras != null ? extras.getLong(NotesDbAdapter.KEY_ROWID) : null; value = extras.getInt("key"); } I'm fairly sure that (mRowId == null) is not true when I'm using the createNote method so therefore getExtras won't be called. One of my questions would be how can I make my NoteEdit class get this value when I use the createNote method? I'm new to this so sorry if this is a simple question for you all. Thanks, Joe

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  • [JAX-B] How can I ignore a superclass?

    - by MrSpandex
    I'm trying to write a web service for the java.util.logging api. So I wrote a class MyLogRecord that inherits from LogRecord. I annotated this class with JAX-B annotations, including @XmlAccessorType(XmlAccessType.NONE) so it would ignore non-annotated fields and properties. When I start up tomcat, I get errors that java.util.logging.Level and other java.util.logging classes do not have a default constructor, but none of my annotated methods make any reference to the Level class or any of the other java.util.logging classes. These are referenced by the parent class. My sub-class has everything it needs defined. How can I get JAX-B to ignore the parent class completely? Update: I found another post on this, which suggests modifying the parent class. This is obviously not possible because I am extending a java.util class. IS there any way to do this without modifying the superclass? Update2: I found a thread on java.net for a similar problem. That thread resulted in an enhancement request, which was marked as a duplicate of another issue, which resulted in the @XmlTransient annotation. The comments on these bug reports lead me to believe this is impossible in the current spec.

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  • static block instance block java Order

    - by Rollerball
    Having read this question In what order are the different parts of a class initialized when a class is loaded in the JVM? and the related JLS. I would like to know in more detail why for example having class Animal (superclass) and class Dog (subclass) as following: class Animal { static{ System.out.println("This is Animal's static block speaking"): } { System.out.println("This is Animal's instance block speaking"); } class Dog{ static{ System.out.println("This is Dog's static block speaking"); } { System.out.println("This is Dog's instance block speaking"); } public static void main (String [] args) { Dog dog = new Dog(); } } Ok before instantiating a class its direct superclass needs to be initialized (therefore all the statics variables and block need to be executed). So basically the question is: Why after initializing the static variables and static blocks of the super class, control goes down to the subclass for static variables initialization rather then finishing off the initialization of also the instance member? The control goes like: superclass (Animal): static variables and static blocks subclass (Dog): static variables and static blocks superclass (Animal): instance variables and instance blocks sublcass (Dog):instance variables and instance blocks What is the reason why it is in this way rather than : superclass -> static members superclass -> instance members subclass -> static members sublcass-> instance members

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  • function pointers callbacks C

    - by robUK
    Hello, I have started to review callbacks. I found this link: http://stackoverflow.com/questions/142789/what-is-a-callback-in-c-and-how-are-they-implemented which has a good example of callback which is very similar to what we use at work. However, I have tried to get it to work, but I have many errors. #include <stdio.h> /* Is the actual function pointer? */ typedef void (*event_cb_t)(const struct event *evt, void *user_data); struct event_cb { event_cb_t cb; void *data; }; int event_cb_register(event_ct_t cb, void *user_data); static void my_event_cb(const struct event *evt, void *data) { /* do some stuff */ } int main(void) { event_cb_register(my_event_cb, &my_custom_data); struct event_cb *callback; callback->cb(event, callback->data); return 0; } I know that callback use function pointers to store an address of a function. But there is a few things that I find I don't understand. That is what is meet by "registering the callback" and "event dispatcher"? Many thanks for any advice,

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  • How to bundle extension methods requiring configuration in a library

    - by Greg
    Hi, I would like to develop a library that I can re-use to add various methods involved in navigating/searching through a graph (nodes/relationships, or if you like vertexs/edges). The generic requirements would be: There are existing classes in the main project that already implement the equivalent of the graph class (which contains the lists of nodes / relationships), node class and relationship class (which links nodes together) - the main project likely already has persistence mechanisms for the info (e.g. these classes might be built using Entity Framework for persistance) Methods would need to be added to each of these 3 classes: (a) graph class - methods like "search all nodes", (b) node class - methods such as "find all children to depth i", c) relationship class - methods like "return relationship type", "get parent node", "get child node". I assume there would be a need to inform the library with the extending methods the class names for the graph/node/relationships table (as different project might use different names). To some extent it would need to be like how a generics collection works (where you pass the classes to the collection so it knows what they are). Need to be a way to inform the library of which node property to use for equality checks perhaps (e.g. if it were a graph of webpages the equality field to use might be the URI path) I'm assuming that using abstract base classes wouldn't really work as this would tie usage down to have to use the same persistence approach, and same class names etc. Whereas really I want to be able to, for a project that has "graph-like" characteristics, the ability to add graph searching/walking methods to it.

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  • What is sr-only in Bootstrap 3?

    - by kanarifugl
    I wonder what the class sr-only is? Is it important or can I remove it? Works fine without and no explanation is given in the documentations. Here's my example: <div class="btn-group"> <button type="button" class="btn btn-info btn-md">Departments</button> <button type="button" class="btn btn-info dropdown-toggle btn-md" data-toggle="dropdown"> <span class="caret"></span> <span class="sr-only">Toggle Dropdown</span> </button> <ul class="dropdown-menu" role="menu"> <li><a href="#">Sales</a></li> <li><a href="#">Technical</a></li> <li class="divider"></li> <li><a href="#">Show all</a></li> </ul> </div>

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  • How to define a collection in a POCO in Entity Framework 4?

    - by Stef
    Lets say I've a Team class which contains 0 or more Players. The Player class is easy: public class Player { public long Id { get; set; } public string Name { get; set; } public Team Team { get; set; } } But whats the best to define the Team class? Option 1 public class Team { public long Id { get; set; } public string Name { get; set; } public ICollection<Player> Players { get; set; } } Option 2: public class Team { public Team() { Players = new Collection<Player>(); } public long Id { get; set; } public string Name { get; set; } public ICollection<Player> Players { get; set; } } Option 3: public class Team { public long Id { get; set; } public string Name { get; set; } public IQueryable<Player> Players { get; set; } } Option 4: public class Team { public long Id { get; set; } public string Name { get; set; } public ObjectSet<Player> Players { get; set; } }

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  • RBG to CbyCr conversion code

    - by user1446688
    I am wondering why this code does not work. Basically it is supposed to convert between RGB and CbYCr. When I convert from RGB to CbYCr then back to RGB I do not get the original RGB values. What is wrong with this code? #define MIN(a,b) (((a)<(b))?(a):(b)) #define MAX(a,b) (((a)(b))?(a):(b)) struct _rgb { int R; int G; int B; }; typedef struct _rgb rgb; struct _cbycr { int Cb; int Y; int Cr; }; typedef struct _cbycr cbycr; void cbycr2rgb(rgb *c, double Y, double Cb, double Cr) { int r = (int)(Y + 1.40200 * (Cr - 0x80)); int g = (int)(Y - 0.34414 * (Cb - 0x80) - 0.71414 * (Cr - 0x80)); int b = (int)(Y + 1.77200 * (Cb - 0x80)); c->R = MAX(0, MIN(255, r)); c->G = MAX(0, MIN(255, g)); c->B = MAX(0, MIN(255, b)); } void rgb2cbycr(cbycr *c, int R, int G, int B) { c->Y = (int)(0.299 * R + 0.587 * G + 0.114 * B); c->Cb = (int)(-0.16874 * R - 0.33126 * G + 0.50000 * B); c->Cr =(int)(0.50000 * R - 0.41869 * G - 0.08131 * B); } int main() { cbycr _cbycr; rgb _rgb; _rgb.R = 50; _rgb.G = 50; _rgb.B = 50; rgb2cbycr(&_cbycr, _rgb.R, _rgb.G, _rgb.B); cbycr2rgb(&_rgb, _cbycr.Y, _cbycr.Cb, _cbycr.Cr); printf("rgb=%d %d %d\n", _rgb.R, _rgb.G, _rgb.B); return 0; } output: rgb=0 185 0

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