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  • How to access base (super) class in Delphi?

    - by Niyoko Yuliawan
    In C# i can access base class by base keyword, and in java i can access it by super keyword. How to do that in delphi? suppose I have following code: type TForm3 = class(TForm) private procedure _setCaption(Value:String); public property Caption:string write _setCaption; //adding override here gives error end; implementation procedure TForm3._setCaption(Value: String); begin Self.Caption := Value; //it gives stack overflow end;

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  • Java Basics: create class object

    - by user1767853
    In C++: class Rectangle { int x, y; public: void set_values (int,int); int area () {return (x*y);} }; int main () { Rectangle rect; rect.set_values (3,4); } In Java: class Rectangle { int x, y; void set_values (int x,int y); int area () {return (x*y);} } public static void main(String[] args) { Rectangle rect=new Rectangle(3,4); } In C++ compiler will create rect object & reserve memory 4 bytes. I want to know How Java is creating object?

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  • How to apply stereotypes on UML Relationships' MemberEnds?

    - by Cristi Potlog
    I'm running this code on a UML Class Diagram, and it works just fine, but when trying to apply stereotypes from PropertiesEditor in Visual Studio for relationship ends (FirstRole and SecondRole), the stereotypes combo doesn't load even if in code there seems to be applicable stereotypes valid for association properties. What should I put in metaclasses tag in the UML profile except for IProperty? <metaclassMoniker name="/MyUmlProfile/Microsoft.VisualStudio.Uml.Classes.IProperty"/> This is the code: using Microsoft.VisualStudio.Uml.Classes; foreach( IShape shape in currentDiagram.GetSelectedShapes<IElement>() ) { IElement element = shape.GetElement(); foreach( IStereotype stereotype in element.ApplicableStereotypes ) { if( element is Microsoft.VisualStudio.Uml.Classes.IClass ) { IClass classItem = (IClass)element; if( classItem.SuperClasses.Count() > 0 ) { if( stereotype.Name == "SubclassAttribute" ) { element.ApplyStereotype( stereotype ); } } else if( stereotype.Name == "ClassAttribute" ) { element.ApplyStereotype( stereotype ); } } else if( element is Microsoft.VisualStudio.Uml.Classes.IProperty ) { IProperty property = (IProperty)element; if( property.Association != null ) { if( stereotype.Name == "Set" && property.UpperValue != null && property.UpperValue.ToString() == "*" ) { element.ApplyStereotype( stereotype ); } else if( stereotype.Name == "ManyToOne" && ( property.UpperValue == null || property.UpperValue.ToString() == "1" ) ) { element.ApplyStereotype( stereotype ); } } else if( stereotype.Name == "Property" ) { element.ApplyStereotype( stereotype ); } } } }

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  • How to use class_eval <<-"end_eval" in Ruby? Not parsing correctly

    - by viatropos
    I would like to define dynamic methods based on some options people give when instantiating it. So in their AR model, they'd do something like this: acts_as_something :class_name => "CustomClass" I'm trying to implement that like so: module MyModule def self.included(base) as = Config.class_name.underscore foreign_key = "#{as}_id" # 1 - class eval, throws these errors # ~/test-project/helpers/form.rb:45: syntax error, unexpected $undefined # @ ||= MyForm.new( # ^ # ~/test-project/helpers/form.rb:46: syntax error, unexpected ',' #~/test-project/helpers/form.rb:48: syntax error, unexpected ')', # expecting kEND from ~/test-project/helpers.rb:12:in `include' base.class_eval <<-"end_eval", __FILE__, __LINE__ attr_accessor :#{as} def #{as} @#{as} ||= MyForm.new( :id => self.#{foreign_key}, :title => self.title ) @#{as} end end_eval end end But it's throwing a bunch of errors I've printed in the comments. Am I using this incorrectly? What are some better ways I can define dynamic method names and dynamic names inside the method like this? I see people use this often instead of define_method (see these classes in resource_controller and couchrest toward the bottom). What I missing here? Thanks for the help

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  • .NET/C#: How to remove/minimize code clutter while 'triggering' Events

    - by eibhrum
    Hi, I just wanna find out if there's a way I could minimize code clutter in my application. I have written code/s similar to this: private void btnNext_MouseEnter(object sender, System.Windows.Input.MouseEventArgs e) { btnNext.Opacity = 1; } private void btnNext_MouseLeave(object sender, System.Windows.Input.MouseEventArgs e) { btnNext.Opacity = 0.5; } private void btnShowAll_MouseEnter(object sender, System.Windows.Input.MouseEventArgs e) { btnShowAll.Opacity = 1; } private void btnShowAll_MouseLeave(object sender, System.Windows.Input.MouseEventArgs e) { btnShowAll.Opacity = 0.5; } private void btnPrev_MouseEnter(object sender, System.Windows.Input.MouseEventArgs e) { btnPrev.Opacity = 1; } private void btnPrev_MouseLeave(object sender, System.Windows.Input.MouseEventArgs e) { btnPrev.Opacity = 0.5; } private void btnSearch_MouseEnter(object sender, System.Windows.Input.MouseEventArgs e) { btnSearch.Opacity = 1; } private void btnSearch_MouseLeave(object sender, System.Windows.Input.MouseEventArgs e) { btnSearch.Opacity = 0.5; } private void btnSearchStore_MouseEnter(object sender, System.Windows.Input.MouseEventArgs e) { btnSearchStore.Opacity = 1; } private void btnSearchStore_MouseLeave(object sender, System.Windows.Input.MouseEventArgs e) { btnSearchStore.Opacity = 0.5; } private void btnCloseSearch_MouseEnter(object sender, System.Windows.Input.MouseEventArgs e) { btnCloseSearch.Opacity = 1; } private void btnCloseSearch_MouseLeave(object sender, System.Windows.Input.MouseEventArgs e) { btnCloseSearch.Opacity = 0.5; } private void btnHome_MouseEnter(object sender, System.Windows.Input.MouseEventArgs e) { btnHome.Opacity = 1; } private void btnHome_MouseLeave(object sender, System.Windows.Input.MouseEventArgs e) { btnHome.Opacity = 0.5; } and so on and so forth... Do I need to create a 'function' that will run initially? Or do I have to create another class just so I can 'organize' them? Any suggestions?

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  • Idiomatic Scala way to deal with base vs derived class field names?

    - by Gregor Scheidt
    Consider the following base and derived classes in Scala: abstract class Base( val x : String ) final class Derived( x : String ) extends Base( "Base's " + x ) { override def toString = x } Here, the identifier 'x' of the Derived class parameter overrides the field of the Base class, so invoking toString like this: println( new Derived( "string" ).toString ) returns the Derived value and gives the result "string". So a reference to the 'x' parameter prompts the compiler to automatically generate a field on Derived, which is served up in the call to toString. This is very convenient usually, but leads to a replication of the field (I'm now storing the field on both Base and Derived), which may be undesirable. To avoid this replication, I can rename the Derived class parameter from 'x' to something else, like '_x': abstract class Base( val x : String ) final class Derived( _x : String ) extends Base( "Base's " + _x ) { override def toString = x } Now a call to toString returns "Base's string", which is what I want. Unfortunately, the code now looks somewhat ugly, and using named parameters to initialize the class also becomes less elegant: new Derived( _x = "string" ) There is also a risk of forgetting to give the derived classes' initialization parameters different names and inadvertently referring to the wrong field (undesirable since the Base class might actually hold a different value). Is there a better way? Edit: To clarify, I really only want the Base values; the Derived ones just seem necessary for initializing the Base ones. The example only references them to illustrate the ensuing issues. It might be nice to have a way to suppress automatic field generation if the derived class would otherwise end up hiding a base class field.

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  • Accessing data stored in another unit Delphi

    - by Hendriksen123
    In Unit2 of my program i have the following code: TValue = Record NewValue, OldValue, SavedValue : Double; end; TData = Class(TObject) Public EconomicGrowth : TValue; Inflation : TValue; Unemployment : TValue; CurrentAccountPosition : TValue; AggregateSupply : TValue; AggregateDemand : TValue; ADGovernmentSpending : TValue; ADConsumption : TValue; ADInvestment : TValue; ADNetExports : TValue; OverallTaxation : TValue; GovernmentSpending : TValue; InterestRates : TValue; IncomeTax : TValue; Benefits : TValue; TrainingEducationSpending : TValue; End; I then declare Data : TData in the Var. when i try to do the following however in Unit1: ShowMessage(FloatToStr(Unit2.Data.Inflation.SavedValue)); I get an EAccessViolation message. Is there any way to access the data stored in 'Data' from Unit1 without getting errors?

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  • How to use URLClassLoader to load a *.class file?

    - by DeletedAccount
    I'm playing around with Reflection and I thought I'd make something which loads a class and prints the names of all fields in the class. I've made a small hello world type of class to have something to inspect: kent@rat:~/eclipsews/SmallExample/bin$ ls IndependentClass.class kent@rat:~/eclipsews/SmallExample/bin$ java IndependentClass Hello! Goodbye! kent@rat:~/eclipsews/SmallExample/bin$ pwd /home/kent/eclipsews/SmallExample/bin kent@rat:~/eclipsews/SmallExample/bin$ Based on the above I draw two conclusions: It exists at /home/kent/eclipsews/SmallExample/bin/IndependentClass.class It works! (So it must be a proper .class-file which can be loaded by a class loader) Then the code which is to use Reflection: (Line which causes an exception is marked) import java.lang.reflect.Field; import java.net.MalformedURLException; import java.net.URL; import java.net.URLClassLoader; public class InspectClass { @SuppressWarnings("unchecked") public static void main(String[] args) throws ClassNotFoundException, MalformedURLException { URL classUrl; classUrl = new URL("file:///home/kent/eclipsews/SmallExample/bin/IndependentClass.class"); URL[] classUrls = { classUrl }; URLClassLoader ucl = new URLClassLoader(classUrls); Class c = ucl.loadClass("IndependentClass"); // LINE 14 for(Field f: c.getDeclaredFields()) { System.out.println("Field name" + f.getName()); } } } But when I run it I get: Exception in thread "main" java.lang.ClassNotFoundException: IndependentClass at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at java.lang.ClassLoader.loadClass(ClassLoader.java:251) at InspectClass.main(InspectClass.java:14) My questions: What am I doing wrong above? How do I fix it? Is there a way to load several class files and iterate over them?

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  • Can a function return an object? Objective-C and NSMutableArray

    - by seaworthy
    I have an NSMutableArray. It's members eventually become members of an array instance in a class. I want to put the instantiantion of NSMutable into a function and to return an array object. If I can do this, I can make some of my code easier to read. Is this possible? Here is what I am trying to figure out. //Definition: > function Objects (float a, float b) { > NSMutableArray *array = [[NSMutableArray alloc] init]; > [array addObject:[NSNumber numberWithFloat:a]]; > [array addObject:[NSNumber numberWithFloat:b]]; > //[release array]; ???????? return array; > } //Declaration: Math *operator = [[Math alloc] init]; [operator findSum:Objects(20.0,30.0)]; My code compiles if I instantiate NSMutableArray right before I send the message to the receiver. I know I can have an array argument along with the method. What I have problem seeing is how to use a function and to replace the argument with a function call. Any help is appreciated. I am interested in the concept not in suggestions to replace the findSum method.

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  • Python OOP and lists

    - by Mikk
    Hi, I'm new to Python and it's OOP stuff and can't get it to work. Here's my code: class Tree: root = None; data = []; def __init__(self, equation): self.root = equation; def appendLeft(self, data): self.data.insert(0, data); def appendRight(self, data): self.data.append(data); def calculateLeft(self): result = []; for item in (self.getLeft()): if (type(item) == type(self)): data = item.calculateLeft(); else: data = item; result.append(item); return result; def getLeft(self): return self.data; def getRight(self): data = self.data; data.reverse(); return data; tree2 = Tree("*"); tree2.appendRight(44); tree2.appendLeft(20); tree = Tree("+"); tree.appendRight(4); tree.appendLeft(10); tree.appendLeft(tree2); print(tree.calculateLeft()); It looks like tree2 and tree are sharing list "data"? At the moment I'd like it to output something like [[20,44], 10, 4], but when I tree.appendLeft(tree2) I get RuntimeError: maximum recursion depth exceeded, and when i even won't appendLeft(tree2) it outputs [10, 20, 44, 4] (!!!). What am I missing here? I'm using Portable Python 3.0.1. Thank you

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  • I'm making a simulated tv

    - by Jam
    I need to make a tv that shows the user the channel and the volume, and shows whether or not the television is on. I have the majority of the code made, but for some reason the channels won't switch. I'm fairly unfamiliar with how properties work, and I think that's what my problem here is. Help please. class Television(object): def __init__(self, __channel=1, volume=1, is_on=0): self.__channel=__channel self.volume=volume self.is_on=is_on def __str__(self): if self.is_on==1: print "The tv is on" print self.__channel print self.volume else: print "The television is off." def toggle_power(self): if self.is_on==1: self.is_on=0 return self.is_on if self.is_on==0: self.is_on=1 return self.is_on def get_channel(self): return channel def set_channel(self, choice): if self.is_on==1: if choice>=0 and choice<=499: channel=self.__channel else: print "Invalid channel!" else: print "The television isn't on!" channel=property(get_channel, set_channel) def raise_volume(self, up=1): if self.is_on==1: self.volume+=up if self.volume>=10: self.volume=10 print "Max volume!" else: print "The television isn't on!" def lower_volume(self, down=1): if self.is_on==1: self.volume-=down if self.volume<=0: self.volume=0 print "Muted!" else: print "The television isn't on!" def main(): tv=Television() choice=None while choice!="0": print \ """ Television 0 - Exit 1 - Toggle Power 2 - Change Channel 3 - Raise Volume 4 - Lower Volume """ choice=raw_input("Choice: ") print if choice=="0": print "Good-bye." elif choice=="1": tv.toggle_power() tv.__str__() elif choice=="2": change=raw_input("What would you like to change the channel to?") tv.set_channel(change) tv.__str__() elif choice=="3": tv.raise_volume() tv.__str__() elif choice=="4": tv.lower_volume() tv.__str__() else: print "\nSorry, but", choice, "isn't a valid choice." main() raw_input("Press enter to exit.")

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  • Problem with for-loop in python

    - by Protean
    This code is supposed to be able to sort the items in self.array based upon the order of the characters in self.order. The method sort runs properly until the third iteration, unil for some reason the for loop seems to repeat indefinitely. What is going on here? class sorting_class: def __init__(self): self.array = ['ca', 'bd', 'ac', 'ab'] #An array of strings self.arrayt = [] self.globali = 0 self.globalii = 0 self.order = ['a', 'b', 'c', 'd'] #Order of characters self.orderi = 0 self.carry = [] self.leave = [] self.sortedlist = [] def sort(self): for arrayi in self.arrayt: #This should only loop for the number items in self.arrayt. However, the third time this is run it seems to loop indefinitely. print ('run', arrayi) #Shows the problem if self.order[self.orderi] == arrayi[self.globali]: self.carry.append(arrayi) else: if self.globali != 0: self.leave.append(arrayi) def srt(self): self.arrayt = self.array my.sort() #First this runs the first time. while len(self.sortedlist) != len(self.array): if len(self.carry) == 1: self.sortedlist.append(self.carry) self.arrayt = self.leave self.leave = [] self.carry = [] self.globali = 1 self.orderi = 0 my.sort() elif len(self.carry) == 0: if len(self.leave) != 0: #Because nothing matches 'aa' during the second iteration, this code runs the third time" self.arrayt = self.leave self.globali = 1 self.orderi += 1 my.sort() else: self.arrayt = self.array self.globalii += 1 self.orderi = self.globalii self.globali = 0 my.sort() self.orderi = 0 else: #This is what runs the second time. self.arrayt = self.carry self.carry = [] self.globali += 1 my.sort() my = sorting_class() my.srt()

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  • How would you code an efficient Circular Buffer in Java or C#

    - by Cheeso
    I want a simple class that implements a fixed-size circular buffer. It should be efficient, easy on the eyes, generically typed. EDIT: It need not be MT-capable, for now. I can always add a lock later, it won't be high-concurrency in any case. Methods should be: .Add and I guess .List, where I retrieve all the entries. On second thought, Retrieval I think should be done via an indexer. At any moment I will want to be able to retrieve any element in the buffer by index. But keep in mind that from one moment to the next Element[n] may be different, as the Circular buffer fills up and rolls over. This isn't a stack, it's a circular buffer. Regarding "overflow": I would expect internally there would be an array holding the items, and over time the head and tail of the buffer will rotate around that fixed array. But that should be invisible from the user. There should be no externally-detectable "overflow" event or behavior. This is not a school assignment - it is most commonly going to be used for a MRU cache or a fixed-size transaction or event log.

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  • What does it mean to pass a &variable to a function? E.g., string& insert ( size_t pos1, const strin

    - by Bob Montgomery
    I understand passing a pointer, and returning a pointer: char * strcat ( char * destination, const char * source ); You're passing a variable that contains the address to a char; returning the same. But what does it mean to pass something using the reference operator? Or to return it? string& insert ( size_t pos1, const string& str ); I mean, I understand what actually happens, I just don't understand the notation. Why isn't the notation this instead: string * insert ( size_t pos1, const string * str ); //made up I presume it has something to do with passing/returning the instance of a class, but what? Is this syntax valid; if not why not and if so what does it mean? char & strcat ( char & destination, const char & source ); //made up (all of the function declarations, except the last made-up two, are from http://www.cplusplus.com )

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  • [C++] A minimalistic smart array (container) class template

    - by legends2k
    I've written a (array) container class template (lets call it smart array) for using it in the BREW platform (which doesn't allow many C++ constructs like STD library, exceptions, etc. It has a very minimal C++ runtime support); while writing this my friend said that something like this already exists in Boost called MultiArray, I tried it but the ARM compiler (RVCT) cries with 100s of errors. I've not seen Boost.MultiArray's source, I've just started learning template only lately; template meta programming interests me a lot, although am not sure if this is strictly one, which can be categorised thus. So I want all my fellow C++ aficionados to review it ~ point out flaws, potential bugs, suggestions, optimisations, etc.; somthing like "you've not written your own Big Three which might lead to...". Possibly any criticism that'll help me improve this class and thereby my C++ skills. smart_array.h #include <vector> using std::vector; template <typename T, size_t N> class smart_array { vector < smart_array<T, N - 1> > vec; public: explicit smart_array(vector <size_t> &dimensions) { assert(N == dimensions.size()); vector <size_t>::iterator it = ++dimensions.begin(); vector <size_t> dimensions_remaining(it, dimensions.end()); smart_array <T, N - 1> temp_smart_array(dimensions_remaining); vec.assign(dimensions[0], temp_smart_array); } explicit smart_array(size_t dimension_1 = 1, ...) { static_assert(N > 0, "Error: smart_array expects 1 or more dimension(s)"); assert(dimension_1 > 1); va_list dim_list; vector <size_t> dimensions_remaining(N - 1); va_start(dim_list, dimension_1); for(size_t i = 0; i < N - 1; ++i) { size_t dimension_n = va_arg(dim_list, size_t); assert(dimension_n > 0); dimensions_remaining[i] = dimension_n; } va_end(dim_list); smart_array <T, N - 1> temp_smart_array(dimensions_remaining); vec.assign(dimension_1, temp_smart_array); } smart_array<T, N - 1>& operator[](size_t index) { assert(index < vec.size() && index >= 0); return vec[index]; } size_t length() const { return vec.size(); } }; template<typename T> class smart_array<T, 1> { vector <T> vec; public: explicit smart_array(vector <size_t> &dimension) : vec(dimension[0]) { assert(dimension[0] > 0); } explicit smart_array(size_t dimension_1 = 1) : vec(dimension_1) { assert(dimension_1 > 0); } T& operator[](size_t index) { assert(index < vec.size() && index >= 0); return vec[index]; } size_t length() { return vec.size(); } }; Sample Usage: #include <iostream> using std::cout; using std::endl; int main() { // testing 1 dimension smart_array <int, 1> x(3); x[0] = 0, x[1] = 1, x[2] = 2; cout << "x.length(): " << x.length() << endl; // testing 2 dimensions smart_array <float, 2> y(2, 3); y[0][0] = y[0][1] = y[0][2] = 0; y[1][0] = y[1][1] = y[1][2] = 1; cout << "y.length(): " << y.length() << endl; cout << "y[0].length(): " << y[0].length() << endl; // testing 3 dimensions smart_array <char, 3> z(2, 4, 5); cout << "z.length(): " << z.length() << endl; cout << "z[0].length(): " << z[0].length() << endl; cout << "z[0][0].length(): " << z[0][0].length() << endl; z[0][0][4] = 'c'; cout << z[0][0][4] << endl; // testing 4 dimensions smart_array <bool, 4> r(2, 3, 4, 5); cout << "z.length(): " << r.length() << endl; cout << "z[0].length(): " << r[0].length() << endl; cout << "z[0][0].length(): " << r[0][0].length() << endl; cout << "z[0][0][0].length(): " << r[0][0][0].length() << endl; // testing copy constructor smart_array <float, 2> copy_y(y); cout << "copy_y.length(): " << copy_y.length() << endl; cout << "copy_x[0].length(): " << copy_y[0].length() << endl; cout << copy_y[0][0] << "\t" << copy_y[1][0] << "\t" << copy_y[0][1] << "\t" << copy_y[1][1] << "\t" << copy_y[0][2] << "\t" << copy_y[1][2] << endl; return 0; }

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  • How to add a class to just upper element of trigger with Jquery?

    - by Ahmet Kemal
    Hello, I am working on a Jquery accordion stuff. I want to add a class to the div that contains the accordion trigger <a> tag. You can look at my code. I want to add "first" class name to just first "newsitems" class when clicked "Recession fashion in Japan Video" title. <!-- news items starts--> <div class="newsitems"> <h3 class="business"> <a href="#" title="expand"><img src="images/expand_icon.gif" alt="collapse" class="collpase" /> Recession fashion in Japan Video</a> </h3> <p class="timestamp">0100hrs</p> </div> <!-- news items ends--> <!-- news items starts--> <div class="newsitems"> <h3 class="sports"> <a href="#" title="expand"><img src="images/expand_icon.gif" alt="collapse" class="collpase" /> Murray survives five-set thriller at Wimbledon</a> </h3> <p class="timestamp">0100hrs</p> </div> <!-- news items ends-->

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  • Domain validates but won't save

    - by marko
    I have the following setup. Class, say, Car that has a CarPart (belongsTo=[car:Car]). When I'm creating a Car I also want to create som default CarParts, so I do def car = new Car(bla bla bla) def part = new CarPart(car:car) Now, when I do car.validate() or part.validate() it seems fine. But when I do if(car.save && part.save() I get this exception: 2012-03-24 14:02:21,943 [http-8080-4] ERROR util.JDBCExceptionReporter - Batch entry 0 insert into car_part (version, car_id, id) values ('0', '297', '298') was aborted. Call getNextException to see the cause. 2012-03-24 14:02:21,943 [http-8080-4] ERROR util.JDBCExceptionReporter - ERROR: value too long for type character varying(6) 2012-03-24 14:02:21,943 [http-8080-4] ERROR events.PatchedDefaultFlushEventListener - Could not synchronize database state with session org.hibernate.exception.DataException: Could not execute JDBC batch update Stacktrace follows: java.sql.BatchUpdateException: Batch entry 0 insert into car_part (version, deal_id, id) values ('0', '297', '298') was aborted. Call getNextException to see the cause. at org.postgresql.jdbc2.AbstractJdbc2Statement$BatchResultHandler.handleError(AbstractJdbc2Statement.java:2621) at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1837) at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:407) at org.postgresql.jdbc2.AbstractJdbc2Statement.executeBatch(AbstractJdbc2Statement.java:2754) at $Proxy20.flush(Unknown Source) at ristretto.DealController$_closure5.doCall(DealController.groovy:109) at ristretto.DealController$_closure5.doCall(DealController.groovy) at java.lang.Thread.run(Thread.java:722) Any ideas?

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  • Learning OOP in PHP, trying to refactor my code. Can't connect to database anymore.

    - by Cortopasta
    Thought I understood how classes work, then I tried this code: class user { var $dbcon; var $dbinfo; var $con; var $error; function dbConnect() { $this->dbinfo['server'] = "localhost"; $this->dbinfo['database'] = "foolish_faith"; $this->dbinfo['user'] = "user"; $this->dbinfo['password'] = "password"; $this->con = "mysql:host=".$dbinfo['server']."; dbname=".$dbinfo['database']; $this->dbcon = new PDO($con, $dbinfo['user'], $dbinfo['password']); $this->dbcon->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); $this->error = $this->dbcon->errorInfo(); if ($error[0] != "") { print "Error!"; print_r($error); } } } Now it just spits out this error: Fatal error: Uncaught exception 'PDOException' with message 'invalid data source name' in E:\PortableApps\xampp\htdocs\dbcon.php:24 Stack trace: #0 E:\PortableApps\xampp\htdocs\dbcon.php(24): PDO-__construct('', NULL, NULL) #1 E:\PortableApps\xampp\htdocs\login.php(4): user-dbConnect() #2 {main} thrown in E:\PortableApps\xampp\htdocs\dbcon.php on line 24 Can anybody see what I'm doing wrong, as I'm sure it has to do with my lack of knowledge when it comes to classes?

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  • Java Matrix Transpose strangeness going on

    - by user1459976
    ok so im making my own Matrix class. and i have a transpose method that transposes a matrix. this is the block in the main method Matrix m1 = new Matrix(4,2); m1.fillMatrix(1,2,3,4,5,6,7,8); System.out.println("before " + m1.toString()); m1.transpose(); System.out.println("after " + m1.toString()); this is where it gets messed up, at m1.transpose(); in the transpose() method public Matrix transpose() { if(isMatrix2) { Matrix tempMatrix = new Matrix(row, col); // matrix2 contents are emptied once this line is executed for(int i=0; i < row; i++) { for(int j=0; j < col; j++) tempMatrix.matrix2[i][j] = matrix2[i][j]; } so for some reason, the tempMatrix.matrix2 has the same id as this.matrix2. so when the codes executes Matrix tempMatrix = new Matrix(row,col); then the contents of this.matrix2 is emptied. anyone know what might be going on here?

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  • Python OOP - object has no attribute

    - by user1744269
    I am attempting to learn how to program. I really do want to learn how to program; I love the building and design aspect of it. However, in Java and Python, I have tried and failed with programs as they pertain to objects, classes, methods.. I am trying to develop some code for a program, but im stumped. I know this is a simple error. However I am lost! I am hoping someone can guide me to a working program, but also help me learn (criticism is not only expected, but APPRECIATED). class Converter: def cTOf(self, numFrom): numFrom = self.numFrom numTo = (self.numFrom * (9/5)) + 32 print (str(numTo) + ' degrees Farenheit') return numTo def fTOc(self, numFrom): numFrom = self.numFrom numTo = ((numFrom - 32) * (5/9)) return numTo convert = Converter() numFrom = (float(input('Enter a number to convert.. '))) unitFrom = input('What unit would you like to convert from.. ') unitTo = input('What unit would you like to convert to.. ') if unitFrom == ('celcius'): convert.cTOf(numFrom) print(numTo) input('Please hit enter..') if unitFrom == ('farenheit'): convert.fTOc(numFrom) print(numTo) input('Please hit enter..')

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  • Is there a language or design pattern that allows the *removal* of object behavior or properties in a class hierarchy?

    - by Sebastien Diot
    A well-know shortcoming of traditional class hierarchies is that they are bad when it comes to model the real world. As an example, trying to represent animals species with classes. There are actually several problems when doing that, but one that I never saw a solution to is when a sub-class "looses" a behavior or properties that was defined in a super-class, like a penguin not being able to fly (there are probably better examples, but that's the first one that comes to my mind, having seen "Madagascar 2" recently). On the one hand, you don't want to define for every property and behavior some flag that specifies if it is at all present, and check it every time before accessing that behavior or property. You would just like to say that birds can fly, simply and clearly, in the Bird class. But then it would be nice if one could define "exceptions" afterward, without having to use some horrible hacks everywhere. This often happens when a system has been productive for a while. You suddenly find an "exception" that doesn't fit in the original design at all, and you don't want to change a large portion of your code to accommodate it. So, is there some language or design patterns that can cleanly handle this problem, without requiring major changes to the "super-class", and all the code that uses it? Even if a solution only handle a specific case, several solutions might together form a complete strategy. [EDIT] Forgot about the Liskov Substitution Principle. That is why you can't do it. Assuming you define "traits/interfaces" for all major "feature groups", you can freely implement traits in different branches of the hierarchy, like the Flying trait could be implemented by Birds, and some special kind of squirrels and fish. So my question could amount to "How could I un-implement a trait?" If your super-class is a Java Serializable, you have to be one too, even if there is no way for you to serialize your state, for example if you contained a "Socket". So one way to do it is to always define all your traits in pair from the start: Flying and NotFlying (which would throw UnsupportedOperationExceiption, if not checked against). The Not-trait would not define any new interface, and could be simply checked for. Sounds like a "cheap" solution, in particular if used from the start.

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  • Is it better to load up a class with methods or extend member functionality in a local subclass?

    - by Calvin Fisher
    Which is better? Class #1: public class SearchClass { public SearchClass (string ProgramName) { /* Searches LocalFile objects, handles exceptions, and puts results into m_Results. */ } DateTime TimeExecuted; bool OperationSuccessful; protected List<LocalFile> m_Results; public ReadOnlyCollection<LocalFile> Results { get { return new ReadOnlyCollection<LocalFile>(m_Results); } } #region Results Filters public DateTime OldestFileModified { get { /* Does what it says. */ } } public ReadOnlyCollection<LocalFile> ResultsWithoutProcessFiles() { return new ReadOnlyCollection<LocalFile> ((from x in m_Results where x.FileTypeID != FileTypeIDs.ProcessFile select x).ToList()); } #endregion } Or class #2: public class SearchClass { public SearchClass (string ProgramName) { /* Searches LocalFile objects, handles exceptions, and puts results into m_Results. */ } DateTime TimeExecuted; bool OperationSuccessful; protected List<LocalFile> m_Results; public ReadOnlyCollection<LocalFile> Results { get { return new ReadOnlyCollection<LocalFile>(m_Results); } } public class SearchResults : ReadOnlyCollection<LocalFile> { public SearchResults(IList<LocalFile> iList) : base(iList) { } #region Results Filters public DateTime OldestFileModified { get { /* Does what it says. */ } } public ReadOnlyCollection<LocalFile> ResultsWithoutProcessFiles() { return new ReadOnlyCollection<LocalFile> ((from x in this where x.FileTypeID != FileTypeIDs.ProcessFile select x).ToList()); } #endregion } } ...with the implication that OperationSuccessful is accompanied by a number of more interesting properties on how the operation went, and OldestFileModified and ResultsWithoutProcessFiles() also have several more siblings in the Results Filters section.

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