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  • When do instance variables get initialized and values assigned?

    - by AKh
    When doees the instance variable get initialized? Is it after the constructor block is done or before it? Consider this example: public abstract class Parent { public Parent(){ System.out.println("Parent Constructor"); init(); } public void init(){ System.out.println("parent Init()"); } } public class Child extends Parent { private Integer attribute1; private Integer attribute2 = null; public Child(){ super(); System.out.println("Child Constructor"); } public void init(){ System.out.println("Child init()"); super.init(); attribute1 = new Integer(100); attribute2 = new Integer(200); } public void print(){ System.out.println("attribute 1 : " +attribute1); System.out.println("attribute 2 : " +attribute2); } } public class Tester { public static void main(String[] args) { Parent c = new Child(); ((Child)c).print(); } } OUTPUT: Parent Constructor Child init() parent Init() Child Constructor attribute 1 : 100 attribute 2 : null When the memory for the atribute 1 & 2 are allocated in the heap ? Curious to know why is attribute 2 is NULL ? Are there any design flaws?

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  • Parse error: syntax error, unexpected T_STRING in...

    - by rabidmachine9
    I' making this class to catch twitter posts but I get the error : Parse error: syntax error, unexpected T_STRING in /Applications/XAMPP/xamppfiles/htdocs/classTest/Twitter.php on line 29 I cant find what's wrong...any ideas? class TwitterGrub{ function twitterCapture($user = 'myUsername',$password = 'myPass') { $ch = curl_init("https://twitter.com/statuses/user_timeline.xml"); curl_setopt($ch, CURLOPT_HEADER, 1); curl_setopt($ch,CURLOPT_TIMEOUT, 30); curl_setopt($ch,CURLOPT_USERPWD,$user . ":" . $password); curl_setopt($ch,CURLOPT_RETURNTRANSFER,1); curl_setopt ($ch, CURLOPT_SSL_VERIFYPEER, 0); curl_setopt ($ch, CURLOPT_SSL_VERIFYHOST, 0); $result=curl_exec ($ch); $data = strstr($result, '<?'); $xml = new SimpleXMLElement($data); return $xml; } function twitterDisplay($twitNum){ $xml = this->twitterCapture(); for($i= 0; $i<$twitNum; $i++){ echo "<div class='curvebox'>".$xml->status[$i]->text."</div>"; } } }

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  • What do I name classes whose only purpose is to act as a structure?

    - by Sergio Tapia
    For example, take my Actor class: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Drawing; namespace FreeIMDB { class Actor { public string Name { get; set; } public Image Portrait { get; set; } public DateTime DateOfBirth { get; set; } public List<string> ActingRoles { get; set; } public List<string> WritingRoles { get; set; } public List<string> ProducingRoles { get; set; } public List<string> DirectingRoles { get; set; } } } This class will only be used to stuff information into it, and allow other developers to get their values. What are these types of classes officially called? What is the correct nomenclature?

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  • Flash compiler error 1061: Call to a possibly undefined method run... but run exists!

    - by Zane Geiger
    So I've been working on making a game in Processing but I think Flash would be a better way to get more people playing it, so I've decided to learn Flash. The problem is that I keep getting really stupid errors on incredibly simple things. For instance, I want to make a 'Block' object to use in a platform game. So I make a new .as file, name it Block.as, and define the Block class within it like so: package { public class Block { public function Block() { // constructor code } public function run() { } } } I don't want to add the code yet, I just want to ensure that this works. So in my main timeline code, I try to create an instance of the Block object and execute its run method: var block1:Block = new Block(); block1.run(); Every time it gives me this inane error: Scene 1, Layer 'Layer 1', Frame 1, Line 2 1061: Call to a possibly undefined method run through a reference with static type Block. What undefined method!? It's defined RIGHT THERE in Block.as. The class file is even in the same folder and everything. I'm getting REALLY annoyed at how poorly Flash handles such a ridiculously simple project. Does anyone know why Flash hates me?

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  • Is it true that in most Object Oriented Programming Languages, an "i" in an instance method always r

    - by Jian Lin
    In the following code: <script type="text/javascript"> var i = 10; function Circle(radius) { this.r = radius; this.i = radius; } Circle.i = 123; Circle.prototype.area = function() { alert(i); } var c = new Circle(1); var a = c.area(); </script> What is being alerted? The answer is at the end of this question. I found that the i in the alert call either refers to any local (if any), or the global variable. There is no way that it can be the instance variable or the class variable even when there is no local and no global defined. To refer to the instance variable i, we need this.i, and to the class variable i, we need Circle.i. Is this actually true for almost all Object oriented programming languages? Any exception? Are there cases that when there is no local and no global, it will look up the instance variable and then the class variable scope? (or in this case, are those called scope?) the answer is: 10 is being alerted.

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  • Segmentation fault on instationation of more than 1 object

    - by ECE
    I have a class called "Vertex.hpp" which is as follows: #include <iostream> #include "Edge.hpp" #include <vector> using namespace std; /** A class, instances of which are nodes in an HCTree. */ class Vertex { public: Vertex(char * str){ *name=*str; } vector<Vertex*> adjecency_list; vector<Edge*> edge_weights; char *name; }; #endif When I instantiate an object of type Vector as follows: Vertex *first_read; Vertex *second_read; in.getline(input,256); str=strtok(input," "); first_read->name=str; str=strtok(NULL, " "); second_read->name=str; A segmentation fault occurs when more than 1 object of type Vector is instantiated. Why would this occur if more than 1 object is instantiated, and how can i allow multiple objects to be instantiated?

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  • AttributeError in my Python program regarding classes

    - by Axel Finkel
    I'm doing an exercise out of the Python book that involves creating a class and a subclass. I am getting the following error when I try to run the program: AttributeError: 'Customer' object has no attribute 'name', when it tries to go through this bit of code: self.name.append(name) As this is my first time dealing with classes and objects in Python, I'm sure I am making some overt mistake somewhere, but I can't seem to figure it out. I've looked over the documentation for creating classes and writing member functions, and it looks correct, but it is obviously not. I want the Customer subclass to inherit the name, address, and telephone attributes from the Person superclass, but it doesn't seem to be doing so? Here is my code: class Person: def __init__(self): self.name = None self.address = None self.telephone = None def changeName(self, name): self.name.append(name) def changeAddress(self, address): self.address.append(address) def changeTelephone(self, telephone): self.telephone.append(telephone) class Customer(Person): def __init__(self): self.customerNumber = None self.onMailingList = False def changeCustomerNumber(self, customerNumber): self.customerNumber.append(customerNumber) def changeOnMailingList(): if onMailingList == False: onMailingList == True else: onMailingList == False def main(): customer1 = Customer() name = 'Bob Smith' address = '123 Somewhere Road' telephone = '111 222 3333' customerNumber = '12345' customer1.changeName(name) customer1.changeAddress(address) customer1.changeTelephone(telephone) customer1.changeCustomerNumber(customerNumber) print("Customer name: " + customer1.name) print("Customer address: " + customer1.address) print("Customer telephone number: " + customer1.telephone) print("Customer number: " + customer1.customerNumber) print("On mailing list: " + customer1.OnMailingList) customer1.changeOnMailingList() print("On mailing list: " + customer1.OnMailingList) main()

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  • C++ class functions calling fortran subroutine

    - by user2863626
    Okay so I am trying to make my code work. It is a simple C++ program with a class "CArray". This class has 2 properties, the array size, and the value. I want the main C++ program to create two instances of the class CArray. In the class CArray, I have a function called "AddArray( CArray )" where it adds another array to the current array. The problem I am stuck with, is that I want the function "AddArray" to add the two arrays in fortran. I know, much more complicated, but that is what I need. I am having issues with linking the two inside the class code. #include <iostream> using namespace std; class CArray { public: CArray(); ~CArray(); int Size; int* Val; void SetSize( int ); void SetValues(); void GetArray(); extern "C" { void Add( int*, int*, int*, int*); void Subtract( int*, int*, int*, int*); void Muliply( int*, int*, int *, int* ); } void AddArray( CArray ); void SubtractArray( CArray ); void MultiplyArray( CArray ); }; Also here is the CArray function file. #include "Array.h" #include <iostream> using namespace std; CArray::CArray() { } CArray::~CArray() { } void CArray::SetSize( int s ) { Size = s; for ( int i=0; i<s; i++ ) { Val = new int[Size]; } } void CArray::SetValues() { for ( int i=0; i<Size; i++ ) { cout << "Element " << i+1 << ": "; cin >> Val[i]; } } void CArray::GetArray() { for ( int i=0; i<Size; i++ ) { cout << Val[i] << " "; } } void CArray::AddArray( CArray a ) { if ( Size == a.Size ) { Add(&Val, &a.Val); } else { cout << "Array dimensions do not agree!" << endl; } } void CArray::SubtractArray( CArray a ) { Subtract( &Val, &a, &Size, &a.Size); GetArray(); } Here is my Fortran code. module SubtractArrays use ico_c_binding implicit none contains subroutine Subtract(a,b,s1,s2) bind(c,name='Subtract') integer s1,s2 integer a(s1),b(s2) if ( s1.eq.s2 ) do i=1,s1 a(i) = a(i) - b(i) end return end end If someone could just help me with setting me up to send arrays of integers from C++ classes to fortran I would greatly appreciate it! Thank you, Josh Derrick

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  • How to loop through an array return from the Query of Mysql

    - by Jerry
    This might be easy for you guys but i could't get it. I have a php class that query the database and return the query result. I assign the result to an array and wants to use it on my main.php script. I have tried to use echo $var[0] or echo $var[1] but the output are 'array' instead of my value. Anyone can help me about this issue? Thanks a lot! My php class <?php class teamQuery { function teamQuery(){ } function getAllTeam(){ $connection = mysql_connect(DB_SERVER,DB_USER,DB_PASS); if (!$connection) { die("Database connection failed: " . mysql_error()); } $db_select = mysql_select_db(DB_NAME,$connection); if (!$db_select) { die("Database selection failed: " . mysql_error()); } $teamQuery=mysql_query("SELECT * FROM team", $connection); if (!$teamQuery){ die("database has errors: ".mysql_error()); } $ret = array(); while($row=mysql_fetch_array($teamQuery)){ $ret[]=$row; } mysql_free_result($teamQuery); return $ret; } } ?> My php on the main.php $getTeam=new teamQuery(); $team=$getTeam->getAllTeam(); //echo $team[0] or team[1] output 'array' string! // while($team){ // do something } can't work either // How to loop through the values?? Thanks!

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  • Implement two functions with the same name but different, non-covariant return types due to multiple abstract base classes

    - by user1508167
    If I have two abstract classes defining a pure virtual function with the same name, but different, non-covariant return types, how can I derive from these and define an implementation for both their functions? #include <iostream> class ITestA { public: virtual ~ITestA() {}; virtual float test() =0; }; class ITestB { public: virtual ~ITestB() {}; virtual bool test() =0; }; class C : public ITestA, public ITestB { public: /* Somehow implement ITestA::test and ITestB::test */ }; int main() { ITestA *a = new C(); std::cout << a->test() << std::endl; // should print a float, like "3.14" ITestB *b = dynamic_cast<ITestB *>(a); if (b) { std::cout << b->test() << std::endl; // should print "1" or "0" } delete(a); return 0; } As long as I don't call C::test() directly there's nothing ambiguous, so I think that it should work somehow and I guess I just didn't find the right notation yet. Or is this impossible, if so: Why?

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  • Class Problem (c++ and prolog)

    - by Joshua Green
    I am using the C++ interface to Prolog (the classes and methods of SWI-cpp.h). For working out a simple backtracking that john likes mary and emma and sara: likes(john, mary). likes(john, emma). likes(john, ashley). I can just do: { PlFrame fr; PlTermv av(2); av[0] = PlCompound("john"); PlQuery q("likes", av); while (q.next_solution()) { cout << (char*)av[1] << endl; } } This works in a separate code, so the syntax is correct. But I am also trying to get this simple backtracking to work within a class: class UserTaskProlog { public: UserTaskProlog(ArRobot* r); ~UserTaskProlog(); protected: int cycles; char* argv[1]; ArRobot* robot; void logTask(); }; This class works fine, with my cycles variable incrementing every robot cycle. However, when I run my main code, I get an Unhandled Exception error message: UserTaskProlog::UserTaskProlog(ArRobot* r) : robotTaskFunc(this, &UserTaskProlog::logTask) { cycles = 0; PlEngine e(argv[0]); PlCall("consult('myFile.pl')"); robot->addSensorInterpTask("UserTaskProlog", 50, &robotTaskFunc); } UserTaskProlog::~UserTaskProlog() { robot->remSensorInterpTask(&robotTaskFunc); // Do I need a destructor here for pl? } void UserTaskProlog::logTask() { cycles++; cout << cycles; { PlFrame fr; PlTermv av(2); av[0] = PlCompound("john"); PlQuery q("likes", av); while (q.next_solution()) { cout << (char*)av[1] << endl; } } } I have my opening and closing brackets for PlFrame. I have my frame, my query, etc... The exact same code that backtracks and prints out mary and emma and sara. What am I missing here that I get an error message? Here is what I think the code should do: I expect mary and emma and sara to be printed out once, every time cycles increments. However, it opens SWI-cpp.h file automatically and points to class PlFrame. What is it trying to tell me? I don't see anything wrong with my PlFrame class declaration. Thanks,

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  • CSS class not having an effect on a div

    - by ETFairfax
    Hi Peeps, The following is an section of my css file plus some HTML. Can anyone tell me when I put class="containerHeader selected" (as is on Test Header A) the background colour is not being set to Red??? Cheers, ET Fairfax. div#builderContainer { margin-top: 15px; width: 390px; height: 700px; border: solid 0px #CCCCCC; background-repeat: no-repeat; } div#builderContainer .container { display: none; -moz-border-radius: 4px; -webkit-border-radius: 4px; border-radius: 4px; /* Corner radius */ border: solid 1px #999999; } div#builderContainer .container div:hover { background-color: #EEEEEE; } div#builderContainer .containerHeader { -moz-border-radius: 4px; -webkit-border-radius: 4px; border-radius: 4px; background: #93c3cd url(images/ui-bg_diagonals-small_50_93c3cd_40x40.png) 50% 50% repeat; border-bottom: solid 0px #999999; margin: 0px; margin-top: 25px; padding: 10px; /* display: none; */ border: solid 1px #999999; font-weight: bold; font-family: Verdana; background-color: #FFF; cursor: pointer; vertical-align: middle; } div#builderContainer .containerHeader:hover { background: #ccd232 url(images/ui-bg_diagonals-small_75_ccd232_40x40.png) 50% 50% repeat; } div#builderContainer .containerHeader:active { background: #db4865 url(images/ui-bg_diagonals-small_40_db4865_40x40.png) 50% 50% repeat; } div#builderContainer .containerHeader .selected { background-color: Red; } <div id="builderContainer"> <div class="containerHeader selected" id="CHA">Test Header A</div> <div class="container" id="CA"></div> <div class="containerHeader" id="CHB">Test Header B</div> <div class="container" id="CB"></div> </div>

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  • synchronizing XML nodes between class and file using C#

    - by Sarah Vessels
    I'm trying to write an IXmlSerializable class that stays synced with an XML file. The XML file has the following format: <?xml version="1.0" encoding="utf-8" ?> <configuration> <logging> <logLevel>Error</logLevel> </logging> ...potentially other sections... </configuration> I have a DllConfig class for the whole XML file and a LoggingSection class for representing <logging> and its contents, i.e., <logLevel>. DllConfig has this property: [XmlElement(ElementName = LOGGING_TAG_NAME, DataType = "LoggingSection")] public LoggingSection Logging { get; protected set; } What I want is for the backing XML file to be updated (i.e., rewritten) when a property is set. I already have DllConfig do this when Logging is set. However, how should I go about doing this when Logging.LogLevel is set? Here's an example of what I mean: var config = new DllConfig("path_to_backing_file.xml"); config.Logging.LogLevel = LogLevel.Information; // not using Logging setter, but a // setter on LoggingSection, so how // does path_to_backing_file.xml // have its contents updated? My current solution is to have a SyncedLoggingSection class that inherits from LoggingSection and also takes a DllConfig instance in the constructor. It declares a new LogLevel that, when set, updates the LogLevel in the base class and also uses the given DllConfig to write the entire DllConfig out to the backing XML file. Is this a good technique? I don't think I can just serialize SyncedLoggingSection by itself to the backing XML file, because not all of the contents will be written, just the <logging> node. Then I'd end up with an XML file containing only the <logging> section with its updated <logLevel>, instead of the entire config file with <logLevel> updated. Hence, I need to pass an instance of DllConfig to SyncedLoggingSection. It seems almost like I want an event handler, one in DllConfig that would notice when particular properties (i.e., LogLevel) in its properties (i.e., Logging) were set. Is such a thing possible?

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  • Winforms: calling entry form function from a different class

    - by samy
    I'm kinda new to programming and got a question on what is a good practice. I created a class that represents a ball and it has a function Jump() that use 2 timers and get the ball up and down. I know that in Winforms you got to call Invalidate() every time you want to repaint the screen, or part of it. I didn't find a good way to do that, so I reference the form in my class, and called Invalidate() inside my ball class every time I need to repaint to ball movement. (this works but I got a feeling that this is not a good practice) Here is the class I created: public class Ball { public Form1 parent;//----> here is the reference to the form public Rectangle ball; Size size; public Point p; Timer timerBallGoUp = new Timer(); Timer timerBallGDown = new Timer(); public int ballY; public Ball(Size _size, Point _p) { size = _size; p = _p; ball = new Rectangle(p, size); } public void Jump() { ballY = p.Y; timerBallGDown.Elapsed += ballGoDown; timerBallGDown.Interval = 50; timerBallGoUp.Elapsed += ballGoUp; timerBallGoUp.Interval = 50; timerBallGoUp.Start(); } private void ballGoUp(object obj,ElapsedEventArgs e) { p.Y++; ball.Location = new Point(ball.Location.X, p.Y); if (p.Y >= ballY + 50) { timerBallGoUp.Stop(); timerBallGDown.Start(); } parent.Invalidate(); // here i call parent.Invalidate() 1 } private void ballGoDown(object obj, ElapsedEventArgs e) { p.Y--; ball.Location = new Point(ball.Location.X, p.Y); if (p.Y <= ballY) { timerBallGDown.Stop(); timerBallGoUp.Start(); } parent.Invalidate(); // here i call parent.Invalidate() 2 } } I'm wondring if there is a better way to do that? (sorry for my english)

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  • Turn class "Interfaceable"

    - by scooterman
    Hi folks, On my company system, we use a class to represent beans. It is just a holder of information using boost::variant and some serialization/deserialization stuff. It works well, but we have a problem: it is not over an interface, and since we use modularization through dlls, building an interface for it is getting very complicated, since it is used in almost every part of our app, and sadly interfaces (abstract classes ) on c++ have to be accessed through pointers, witch makes almost impossible to refactor the entire system. Our structure is: dll A: interface definition through abstract class dll B: interface implementation there is a painless way to achieve that (maybe using templates, I don't know) or I should forget about making this work and simply link everything with dll B? thanks Edit: Here is my example. this is on dll A BeanProtocol is a holder of N dataprotocol itens, wich are acessed by a index. class DataProtocol; class UTILS_EXPORT BeanProtocol { public: virtual DataProtocol& get(const unsigned int ) const { throw std::runtime_error("Not implemented"); } virtual void getFields(std::list<unsigned int>&) const { throw std::runtime_error("Not implemented"); } virtual DataProtocol& operator[](const unsigned int ) { throw std::runtime_error("Not implemented"); } virtual DataProtocol& operator[](const unsigned int ) const { throw std::runtime_error("Not implemented"); } virtual void fromString(const std::string&) { throw std::runtime_error("Not implemented"); } virtual std::string toString() const { throw std::runtime_error("Not implemented"); } virtual void fromBinary(const std::string&) { throw std::runtime_error("Not implemented"); } virtual std::string toBinary() const { throw std::runtime_error("Not implemented"); } virtual BeanProtocol& operator=(const BeanProtocol&) { throw std::runtime_error("Not implemented"); } virtual bool operator==(const BeanProtocol&) const { throw std::runtime_error("Not implemented"); } virtual bool operator!=(const BeanProtocol&) const { throw std::runtime_error("Not implemented"); } virtual bool operator==(const char*) const { throw std::runtime_error("Not implemented"); } virtual bool hasKey(unsigned int field) const { throw std::runtime_error("Not implemented"); } }; the other class (named GenericBean) implements it. This is the only way I've found to make this work, but now I want to turn it in a truly interface and remove the UTILS_EXPORT (which is an _declspec macro), and finally remove the forced linkage of B with A.

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  • Getting my string value from my form into my class( not another form)

    - by jovany
    Hello all, I have a question regarding the some data which is being transfered from one form to my class. It's not going quite the way i'd like to , so I figured maybe there is someone who could help me. This is my code in my class Public Class DrawableTextBox Inherits Drawable Dim i_testString As Integer Private s_InsertLabel As String Private drawFont As Font Public Sub New(ByVal fore_color As Color, ByVal fill_color As Color, Optional ByVal line_width As Integer = 0, Optional ByVal new_x1 As Integer = 0, Optional ByVal new_y1 As Integer = 0, Optional ByVal new_x2 As Integer = 1, Optional ByVal new_y2 As Integer = 1) MyBase.New(fore_color, fill_color, line_width) X1 = new_x1 Y1 = new_y1 X2 = new_x2 Y2 = new_y2 Trace.WriteLine(s_InsertLabel) End Sub Friend WriteOnly Property _textBox() As String Set(ByVal Value As String) s_InsertLabel = Value Trace.WriteLine(s_InsertLabel) End Set End Property ' Draw the object on this Graphics surface. Public Overrides Sub Draw(ByVal gr As System.Drawing.Graphics) ' Make a Rectangle representing this rectangle. Dim rect As Rectangle = GetBounds() ' Fill the rectangle as usual. Dim fill_brush As New SolidBrush(FillColor) gr.FillRectangle(fill_brush, rect) fill_brush.Dispose() ' See if we're selected. If IsSelected Then ' Draw the rectangle highlighted. Dim highlight_pen As New Pen(Color.Yellow, LineWidth) gr.DrawRectangle(highlight_pen, rect) highlight_pen.Dispose() ' Draw grab handles. Trace.WriteLine("drawing the lines for my textbox") DrawGrabHandle(gr, X1, Y1) DrawGrabHandle(gr, X1, Y2) DrawGrabHandle(gr, X2, Y2) DrawGrabHandle(gr, X2, Y1) Else 'TextBox() Dim fg_pen As New Pen(Color.Red, LineWidth) 'Dim fontSize As Single = 0.1 + ((Y2 - Y1) / 2) Dim fontSize As Single = 20 Try Dim drawFont As New Font("Arial", fontSize, FontStyle.Bold) Trace.WriteLine(s_InsertLabel) gr.DrawString(s_InsertLabel, drawFont, Brushes.Brown, X1, Y1) Catch ex As ArgumentException End Try gr.DrawRectangle(Pens.Azure, rect) ' gr.DrawRectangle(fg_pen, rect) fg_pen.Dispose() End If End Sub Public Function GetValueString(ByVal ValueType As String) Return ValueType End Function ' Return the object's bounding rectangle. Public Overrides Function GetBounds() As System.Drawing.Rectangle Return New Rectangle( _ Min(X1, X2), _ Min(Y1, Y2), _ Abs(100), _ Abs(30)) Trace.WriteLine("don't forget to make variables in GetBounds DrawableTextbox") End Function ' Return True if this point is on the object. Public Overrides Function IsAt(ByVal x As Integer, ByVal y As Integer) As Boolean Return (x >= Min(X1, X2)) AndAlso _ (x <= Max(X1, X2)) AndAlso _ (y >= Min(Y1, Y2)) AndAlso _ (y <= Max(Y1, Y2)) End Function ' Move the second point. Public Overrides Sub NewPoint(ByVal x As Integer, ByVal y As Integer) X2 = x Y2 = y End Sub ' Return True if the object is empty (e.g. a zero-length line). Public Overrides Function IsEmpty() As Boolean Return (X1 = X2) AndAlso (Y1 = Y2) End Function End Class I've got a form with a textbox( form1) in which the text is being inserted and passed through a buttonclick (al via properties). As you can see I've placed several traces and in the property of the class my trace works fine , however if I look in my Draw function it is already gone. And I get a blank trace. Does anyone know what's happening here. thanks in advance. (forgive me I'm new )

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  • Blob object not working properly even though the class is seralized

    - by GustlyWind
    I have class which is seralized and does convert a very large amount of data object to blob to save it to database.In the same class there is decode method to convert blob to the actual object.Following is the code for encode and decode of the object. private byte[] encode(ScheduledReport schedSTDReport) { byte[] bytes = null; try { ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(bos); oos.writeObject(schedSTDReport); oos.flush(); oos.close(); bos.close(); //byte [] data = bos.toByteArray(); //ByteArrayOutputStream baos = new ByteArrayOutputStream(); //GZIPOutputStream out = new GZIPOutputStream(baos); //XMLEncoder encoder = new XMLEncoder(out); //encoder.writeObject(schedSTDReport); //encoder.close(); bytes = bos.toByteArray(); //GZIPOutputStream out = new GZIPOutputStream(bos); //out.write(bytes); //bytes = bos.toByteArray(); } catch (Exception e) { _log.error("Exception caught while encoding/zipping Scheduled STDReport", e); } decode(bytes); return bytes; } /* * Decode the report definition blob back to the * ScheduledReport object. */ private ScheduledReport decode(byte[] bytes) { ByteArrayInputStream bais = new ByteArrayInputStream(bytes); ScheduledReport sSTDR = null; try { ObjectInputStream ois = new ObjectInputStream(bais); //GZIPInputStream in = new GZIPInputStream(bais); //XMLDecoder decoder = new XMLDecoder(in); sSTDR = (ScheduledReport)ois.readObject();//decoder.readObject(); //decoder.close(); } catch (Exception e) { _log.error("IOException caught while decoding/unzipping Scheduled STDReport", e); } return sSTDR; } The problem here is whenver I change something else in this class means any other method,a new class version is created and so the new version the class is unable to decode the originally encoded blob object. The object which I am passing for encode is also seralized object but this problem exists. Any ideas thanks

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  • Cannot instantiate abstract class or interface : problem while persisting

    - by sammy
    i have a class campaign that maintains a list of AdGroupInterfaces. im going to persist its implementation @Entity @Table(name = "campaigns") public class Campaign implements Serializable,Comparable<Object>,CampaignInterface { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @OneToMany ( cascade = {CascadeType.ALL}, fetch = FetchType.EAGER, targetEntity=AdGroupInterface.class ) @org.hibernate.annotations.Cascade( value = org.hibernate.annotations.CascadeType.DELETE_ORPHAN ) @org.hibernate.annotations.IndexColumn(name = "CHOICE_POSITION") private List<AdGroupInterface> AdGroup; public Campaign() { super(); } public List<AdGroupInterface> getAdGroup() { return AdGroup; } public void setAdGroup(List<AdGroupInterface> adGroup) { AdGroup = adGroup; } public void set1AdGroup(AdGroupInterface adGroup) { if(AdGroup==null) AdGroup=new LinkedList<AdGroupInterface>(); AdGroup.add(adGroup); } } AdGroupInterface's implementation is AdGroups. when i add an adgroup to the list in campaign, campaign c; c.getAdGroupList().add(new AdGroups()), etc and save campaign it says"Cannot instantiate abstract class or interface :" AdGroupInterface its not recognizing the implementation just before persisting... Whereas Persisting adGroups separately works. when it is a member of another entity, it doesnt get persisted. import java.io.Serializable; import java.util.List; import javax.persistence.*; @Entity @DiscriminatorValue("1") @Table(name = "AdGroups") public class AdGroups implements Serializable,Comparable,AdGroupInterface{ /** * */ private static final long serialVersionUID = 1L; private Long Id; private String Name; private CampaignInterface Campaign; private MonetaryValue DefaultBid; public AdGroups(){ super(); } public AdGroups( String name, CampaignInterface campaign) { super(); this.Campaign=new Campaign(); Name = name; this.Campaign = campaign; DefaultBid = defaultBid; AdList=adList; } @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="AdGroup_Id") public Long getId() { return Id; } public void setId(Long id) { Id = id; } @Column(name="AdGroup_Name") public String getName() { return Name; } public void setName(String name) { Name = name; } @ManyToOne @JoinColumn (name="Cam_ID", nullable = true,insertable = false) public CampaignInterface getCampaign() { return Campaign; } public void setCampaign(CampaignInterface campaign) { this.Campaign = campaign; } } what am i missing?? please look into it ...

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  • Class hierarchy problem (with generic's variance!)

    - by devoured elysium
    The problem: class StatesChain : IState, IHasStateList { private TasksChain tasks = new TasksChain(); ... public IList<IState> States { get { return _taskChain.Tasks; } } IList<ITask> IHasTasksCollection.Tasks { get { return _taskChain.Tasks; } <-- ERROR! You can't do this in C#! I want to return an IList<ITask> from an IList<IStates>. } } Assuming the IList returned will be read-only, I know that what I'm trying to achieve is safe (or is it not?). Is there any way I can accomplish what I'm trying? I wouldn't want to try to implement myself the TasksChain algorithm (again!), as it would be error prone and would lead to code duplication. Maybe I could just define an abstract Chain and then implement both TasksChain and StatesChain from there? Or maybe implementing a Chain<T> class? How would you approach this situation? The Details: I have defined an ITask interface: public interface ITask { bool Run(); ITask FailureTask { get; } } and a IState interface that inherits from ITask: public interface IState : ITask { IState FailureState { get; } } I have also defined an IHasTasksList interface: interface IHasTasksList { List<Tasks> Tasks { get; } } and an IHasStatesList: interface IHasTasksList { List<Tasks> States { get; } } Now, I have defined a TasksChain, that is a class that has some code logic that will manipulate a chain of tasks (beware that TasksChain is itself a kind of ITask!): class TasksChain : ITask, IHasTasksList { IList<ITask> tasks = new List<ITask>(); ... public List<ITask> Tasks { get { return _tasks; } } ... } I am implementing a State the following way: public class State : IState { private readonly TaskChain _taskChain = new TaskChain(); public State(Precondition precondition, Execution execution) { _taskChain.Tasks.Add(precondition); _taskChain.Tasks.Add(execution); } public bool Run() { return _taskChain.Run(); } public IState FailureState { get { return (IState)_taskChain.Tasks[0].FailureTask; } } ITask ITask.FailureTask { get { return FailureState; } } } which, as you can see, makes use of explicit interface implementations to "hide" FailureTask and instead show FailureState property. The problem comes from the fact that I also want to define a StatesChain, that inherits both from IState and IHasStateList (and that also imples ITask and IHasTaskList, implemented as explicit interfaces) and I want it to also hide IHasTaskList's Tasks and only show IHasStateList's States. (What is contained in "The problem" section should really be after this, but I thought puting it first would be way more reader friendly). (pff..long text) Thanks!

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  • conflicting declaration when filling a static std::map class member variable

    - by Max
    I have a class with a static std::map member variable that maps chars to a custom type Terrain. I'm attempting to fill this map in the class's implementation file, but I get several errors. Here's my header file: #ifndef LEVEL_HPP #define LEVEL_HPP #include <bitset> #include <list> #include <map> #include <string> #include <vector> #include "libtcod.hpp" namespace yarl { namespace level { class Terrain { // Member Variables private: std::bitset<5> flags; // Member Functions public: explicit Terrain(const std::string& flg) : flags(flg) {} (...) }; class Level { private: static std::map<char, Terrain> terrainTypes; (...) }; } } #endif and here's my implementation file: #include <bitset> #include <list> #include <map> #include <string> #include <vector> #include "Level.hpp" #include "libtcod.hpp" using namespace std; namespace yarl { namespace level { /* fill Level::terrainTypes */ map<char,Terrain> Level::terrainTypes['.'] = Terrain("00001"); // clear map<char,Terrain> Level::terrainTypes[','] = Terrain("00001"); // clear map<char,Terrain> Level::terrainTypes['\''] = Terrain("00001"); // clear map<char,Terrain> Level::terrainTypes['`'] = Terrain("00001"); // clear map<char,Terrain> Level::terrainTypes[178] = Terrain("11111"); // wall (...) } } I'm using g++, and the errors I get are src/Level.cpp:15: error: conflicting declaration ‘std::map, std::allocator yarl::level::Level::terrainTypes [46]’ src/Level.hpp:104: error: ‘yarl::level::Level::terrainTypes’ has a previous declaration as ‘std::map, std::allocator yarl::level::Level::terrainTypes’ src/Level.cpp:15: error: declaration of ‘std::map, std::allocator yarl::level::Level::terrainTypes’ outside of class is not definition src/Level.cpp:15: error: conversion from ‘yarl::level::Terrain’ to non-scalar type ‘std::map, std::allocator ’ requested src/Level.cpp:15: error: ‘yarl::level::Level::terrainTypes’ cannot be initialized by a non-constant expression when being declared I get a set of these for each map assignment line in the implementation file. Anyone see what I'm doing wrong? Thanks for your help.

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  • Class template specializations with shared functionality

    - by Thomas
    I'm writing a simple maths library with a template vector type: template<typename T, size_t N> class Vector { public: Vector<T, N> &operator+=(Vector<T, N> const &other); // ... more operators, functions ... }; Now I want some additional functionality specifically for some of these. Let's say I want functions x() and y() on Vector<T, 2> to access particular coordinates. I could create a partial specialization for this: template<typename T> class Vector<T, 3> { public: Vector<T, 3> &operator+=(Vector<T, 3> const &other); // ... and again all the operators and functions ... T x() const; T y() const; }; But now I'm repeating everything that already existed in the generic template. I could also use inheritance. Renaming the generic template to VectorBase, I could do this: template<typename T, size_t N> class Vector : public VectorBase<T, N> { }; template<typename T> class Vector<T, 3> : public VectorBase<T, 3> { public: T x() const; T y() const; }; However, now the problem is that all operators are defined on VectorBase, so they return VectorBase instances. These cannot be assigned to Vector variables: Vector<float, 3> v; Vector<float, 3> w; w = 5 * v; // error: no conversion from VectorBase<float, 3> to Vector<float, 3> I could give Vector an implicit conversion constructor to make this possible: template<typename T, size_t N> class Vector : public VectorBase<T, N> { public: Vector(VectorBase<T, N> const &other); }; However, now I'm converting from Vector to VectorBase and back again. Even though the types are the same in memory, and the compiler might optimize all this away, it feels clunky and I don't really like to have potential run-time overhead for what is essentially a compile-time problem. Is there any other way to solve this?

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  • Getting error "Association references unmapped class" when using interfaces in model

    - by Bjarke
    I'm trying to use the automap functionality in fluent to generate a DDL for the following model and program, but somehow I keep getting the error "Association references unmapped class: IRole" when I call the GenerateSchemaCreationScript method in NHibernate. When I replace the type of the ILists with the implementation of the interfaces (User and Role) everything works fine. What am I doing wrong here? How can I make fluent use the implemented versions of IUser and IRole as defined in Unity? public interface IRole { string Title { get; set; } IList<IUser> Users { get; set; } } public interface IUser { string Email { get; set; } IList<IRole> Roles { get; set; } } public class Role : IRole { public virtual string Title { get; set; } public virtual IList<IUser> Users { get; set; } } public class User : IUser { public virtual string Email { get; set; } public virtual IList<IRole> Roles { get; set; } } I use the following program to generate the DDL using the GenerateSchemaCreationScript in NHibernate: class Program { static void Main(string[] args) { var ddl = new NHibernateSessionManager(); ddl.BuildConfiguration(); } } public class NHibernateSessionManager { private ISessionFactory _sessionFactory; private static IUnityContainer _container; private static void InitContainer() { _container = new UnityContainer(); _container.RegisterType(typeof(IUser), typeof(User)); _container.RegisterType(typeof(IRole), typeof(Role)); } public ISessionFactory BuildConfiguration() { InitContainer(); return Fluently.Configure().Database(MsSqlConfiguration.MsSql2008 .ConnectionString("ConnectionString")) .Mappings(m => m.AutoMappings.Add( AutoMap.AssemblyOf<IUser>())) .ExposeConfiguration(BuildSchema) .BuildSessionFactory(); } private void BuildSchema(Configuration cfg) { var ddl = cfg.GenerateSchemaCreationScript(new NHibernate.Dialect.MsSql2008Dialect()); System.IO.File.WriteAllLines("Filename", ddl); } }

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  • Is there any way to achieve multiple inheritance in php?

    - by Starx
    Lets say I have a parent class class parent { } ..... This parent has three sub class class child1 { } class child2 { } class child3 { } and these child classes have further smaller parts like class child1subpar1 { } class child1subpar2 { public function foo() { echo "hi"; } } class child2subpar1 { } class child2subpar2 { } Now, how to sum this whole up like class child1 extends child1subpar1, child1subpar2 { } class child2 extends child2subpar1, childsubpar1 { } class parent extends child1,child2,child3 { } I need to execute the methods in its inherited classes and do something like this $objparent = new parent; $objparent - foo();

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  • Pointers to class fields

    - by newbie_cpp
    My task is as follows : Using pointers to class fields, create menu allowing selection of ice, that Person can buy in Ice shop. Buyer will be charged with waffel and ice costs. Selection of ice and charging buyers account must be shown in program. Here's my Person class : #include <iostream> using namespace std; class Iceshop { const double waffel_price = 1; public: } class Person { static int NUMBER; char* name; int age; const int number; double plus, minus; public: class Account { int number; double resources; public: Account(int number, double resources) : number(number), resources(resources) {} } Person(const char* n, int age) : name(strcpy(new char[strlen(n)+1],n)), number(++NUMBER), plus(0), minus(0), age(age) {} Person::~Person(){ cout << "Destroying resources" << endl; delete [] name; } friend void show(Person &p); int* take_age(){ return &age; } char* take_name(){ return name; } void init(char* n, int a) { name = n; age = a; } Person& remittance(double d) { plus += d; return *this; } Person& paycheck(double d) { minus += d; return *this; } Account* getAccount(); }; int Person:: Person::Account* Person::getAccount() { return new Account(number, plus - minus); } void Person::Account::remittance(double d){ resources = resources + d; } void Person::Account::paycheck(double d){ resources = resources - d; } void show(Person *p){ cout << "Name: " << p->take_name() << "," << "age: " << p->take_age() << endl; } int main(void) { Person *p = new Person; p->init("Mary", 25); show(p); p->remittance(100); system("PAUSE"); return 0; } How to start this task ? Where and in what form should I store menu options ?

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  • How to return a property name when comparing two properties at class-level

    - by CodeMonkey
    Hi I have implemented an 'EqualTo' Validation Attribute, that compares two Properties of an object, during ModelBinding in ASP.NET MVC 2. The problem I have is not with it not working, because it does work. The problem is, when I do my request - which is an ajax request - I get back errors to my front-end, where it sets a class on the input fields to indicate invalid input. What it does is iterate through a list of Errors (in a JsonResult), and set a class. This is all dandy. But the ValidationAtrribute I am having trouble with is set at a Class-level, i.e., it's not like other ValidationAttributes where you set something like "[Required]" or something like that. [AttributeUsage(AttributeTargets.Class, AllowMultiple=true, Inherited=false)] public class EqualToAttribute : ValidationAttribute { public String SourceProperty { get; set; } public String MatchProperty { get; set; } public EqualToAttribute(string source, string match) { SourceProperty = source; MatchProperty = match; } public override Boolean IsValid(Object value) { Type objectType = value.GetType(); PropertyInfo[] properties = objectType.GetProperties(); object sourceValue = new object(); object matchValue = new object(); Type sourceType = null; Type matchType = null; int counter = 0; foreach (PropertyInfo propertyInfo in properties) { if (propertyInfo.Name == SourceProperty || propertyInfo.Name == MatchProperty) { if (counter == 0) { sourceValue = propertyInfo.GetValue(value, null); sourceType = propertyInfo.GetValue(value, null).GetType(); } if (counter == 1) { matchValue = propertyInfo.GetValue(value, null); matchType = propertyInfo.GetValue(value, null).GetType(); } counter++; if (counter == 2) { break; } } } if (sourceType != null && matchType != null) { return sourceValue.ToString().Equals(matchValue.ToString()); //return Convert.ChangeType(sourceValue, sourceType) == Convert.ChangeType(matchValue, matchType); } return false; } private object _typeId = new object(); public override object TypeId { get { return this._typeId; } } } Now this code works, except for the fact that the validation process does not return which Property failed. And I simply can't figure out how to make it return one of the two. In reality I don't care which one it returns.. because both are failing.. Do you have an idea how to make it return the/or both Property/Properties that is/are failing.

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