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  • Why do memory-managed languages retain the `new` keyword?

    - by Channel72
    The new keyword in languages like Java, Javascript, and C# creates a new instance of a class. This syntax seems to have been inherited from C++, where new is used specifically to allocate a new instance of a class on the heap, and return a pointer to the new instance. In C++, this is not the only way to construct an object. You can also construct an object on the stack, without using new - and in fact, this way of constructing objects is much more common in C++. So, coming from a C++ background, the new keyword in languages like Java, Javascript, and C# seemed natural and obvious to me. Then I started to learn Python, which doesn't have the new keyword. In Python, an instance is constructed simply by calling the constructor, like: f = Foo() At first, this seemed a bit off to me, until it occurred to me that there's no reason for Python to have new, because everything is an object so there's no need to disambiguate between various constructor syntaxes. But then I thought - what's really the point of new in Java? Why should we say Object o = new Object();? Why not just Object o = Object();? In C++ there's definitely a need for new, since we need to distinguish between allocating on the heap and allocating on the stack, but in Java all objects are constructed on the heap, so why even have the new keyword? The same question could be asked for Javascript. In C#, which I'm much less familiar with, I think new may have some purpose in terms of distinguishing between object types and value types, but I'm not sure. Regardless, it seems to me that many languages which came after C++ simply "inherited" the new keyword - without really needing it. It's almost like a vestigial keyword. We don't seem to need it for any reason, and yet it's there. Question: Am I correct about this? Or is there some compelling reason that new needs to be in C++-inspired memory-managed languages like Java, Javascript and C#?

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  • how to architect this to make it unit testable

    - by SOfanatic
    I'm currently working on a project where I'm receiving an object via web service (WSDL). The overall process is the following: Receive object - add/delete/update parts (or all) of it - and return the object with the changes made. The thing is that sometimes these changes are complicated and there is some logic involved, other databases, other web services, etc. so to facilitate this I'm creating a custom object that mimics the original one but has some enhanced functionality to make some things easier. So I'm trying to have this process: Receive original object - convert/copy it to custom object - add/delete/update - convert/copy it back to original object - return original object. Example: public class Row { public List<Field> Fields { get; set; } public string RowId { get; set; } public Row() { this.Fields = new List<Field>(); } } public class Field { public string Number { get; set; } public string Value { get; set; } } So for example, one of the "actions" to perform on this would be to find all Fields in a Row that match a Value equal to something, and update them with some other value. I have a CustomRow class that represents the Row class, how can I make this class unit testable? Do I have to create an interface ICustomRow to mock it in the unit test? If one of the actions is to sum all of the Values in the Fields that have a Number equal to 10, like this function, how can design the custom class to facilitate unit tests. Sample function: public int Sum(FieldNumber number) { return row.Fields.Where(x => x.FieldNumber.Equals(number)).Sum(x => x.FieldValue); } Am I approaching this the wrong way?

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  • Java EE 6????????????????! ??????????????????????J2EE??????????J2EE??????JavaOne Tokyo 2012?????

    - by ??? 03
    Java EE???????Java EE???????????????·????????????Core J2EE Patterns(J2EE????)?????????????????????10???????????????? “????????????”?????????????Java EE??????6?????????WebLogic Server?????????????·???????????????J2EE???????????????????????????????2012?4???????JavaOne Tokyo 2012??????????Java EE 6???J2EE???????????????? ???????????????????????????????J2EE????????????????????Java EE 6??????J2EE???????????????(???)? J2EE???????????3???????????J2EE(J2EE 1.4???Java EE)????????????????????????????????????????J2EE???????????J2EE?????????????????????????????????????????????????????????????????J2EE?????????????·?????????????????????????Core J2EE Patterns??????? ??J2EE?????????10?????????????????????????????Java EE???????????????????????????????????????????????????J2EE?????????????????????/???????????????????????????????J2EE????????????????????3??????????? ?????? ?????????????? ???????????????????1?????????????Java EE 6????????EJB 3.1?JPA(Java Persistence API) 2.0?CDI(Contexts and Dependency Injection) 1.0????????????????????2???????????·????????????????????·?????Java EE????????????????????????3???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????(??)???????????????????????????????(???) Anemic?“??DOM”??????????????????????????????DOM????????????????????Java EE??????????????????????????????·?????????DOM(Domain Object Model)????????????????????? ?????????·???????????????????????????????????????Anemic(??)???DOM?????????????????????????????????????????????????????????????????????????????????Anemic?DOM??????????????????????????????????????????????????????·????????????????Java EE 6??????????????????????????DOM????????????????????????????????????????????????????????????????·???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????DOM??????????????????????????????/????????????????????????????????????????????DOM?????????????DOM?Java EE????????????????????????????(???) ???DOM??????????J2EE???Java EE 6??????????????????????????J2EE??????????????????????Anemic???DOM?????????????????????????DOM???????DAO(Data Access Object)?????????????????????????????????DOM???????????????DOM?????????????????????????????????????????????????????????Java EE???Java EE 6??????JPA 2.0????????????DOM??????????????????????????????DOM????????????????????? ???JPA???????????????????????Java EE????J2EE?????????????????Java EE???????????????????????Java EE????????????DOM?????????????????????????????????????????????????????DOM?????????????????????Java EE???????????????????????????(???)????????????3???????????? ?????????????? ????????????? ????? ?????????????????10????????????J2EE?????????????????????????????????????????????????????????????????Session Fac,ade?Application Service?Business Object(Composite Entity)???????????????Transfer Object?Value List Handler?????????????????????????????????????????????????????????????????????Java EE???????????????????????????????????Business Delegate?Service Locator??????????????Java EE??????????????? Session Fac,ade??????????????????????????????????????????????????????????????Session Fac,ade????????Application Service?Business Object????????????????????????????????Java EE 6???????????????(????)??????????????????Session Fac,ade???????????????????·?????????????????????????????????Application Service?????????????????????·????????????????????????Business Object??????????·?????????POJO??????????????????????????????????????????????????????????????????? J2EE??????????????Java EE 6???????????????????????????????????????Java EE???DAO?Domain Store?????????????Service Activator?Web Service Broker???API??????????????????? ????DAO?????·???????????????????????????????????????????1???????????????·???????????????????????????????????????????????????????????????????????(????)?????????????????????????????????DAO??????????EntityManager???????????????????????????????????DAO?????????????????????????????????????????????????????????????Criteria Object????????????????????????DAO??????????????????????DAO?????????????????? ???Service Activator????????????????????????????????????????????????JMS(Java Message Service)?MDB(Message Driven Bean)????????????????Java EE 6??????EJB 3.1????Session Bean?????·????????????@Asynchronous?????????????????????????????????Future?????????????????????????????????????????Java EE 6?????????????????????Service Activator????????????????? ????????·?????????????????????????????????????????????MDB?????????????????????????????????@Asynchronous?????????SLA????????????????????????????????????????????????????????? ??????????????Web???????????????????????????????????????????JSF(Java Server Faces)?????????????????????JSF???????????????????Intercepting Filter??????????????????????????????????JSF???????????? ??????????J2EE???????????????????????????Java EE?????????????????????????????????????Session Fac,ade?Business Object????Application Service??????????????????????????????????????????????Java EE??????????????????????????????????????????????????????????????????????????????????????????????????????????????

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  • Can a telephony.Phone object be instantiated through the sdk?

    - by Tyler
    I am trying to get a phone object so that I can call and conference two numbers from within my application. I have tried using the static PhoneFactory.makeDefaultPhones((Context)this) but have not had any luck. String phoneFactoryName = "com.android.internal.telephony.PhoneFactory"; String phoneName = "com.android.internal.telephony.Phone"; Class phoneFactoryClass = Class.forName(phoneFactoryName); Class phoneClass = Class.forName(phoneName); Method getDefaultPhone = phoneFactoryClass.getMethod("getDefaultPhone"); Object phoneObject = getDefaultPhone.invoke(null); Error - Caused by java.lang.RuntimeException: PhoneFactory.getDefaultPhone must be called from Looper thread

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  • How should I pass an object wrapping an API to a class using that API?

    - by Billy ONeal
    Hello everyone :) This is a revised/better written version of the question I asked earlier today -- that question is deleted now. I have a project where I'm getting started with Google Mock. I have created a class, and that class calls functions whithin the Windows API. I've also created a wrapper class with virtual functions wrapping the Windows API, as described in the Google Mock CheatSheet. I'm confused however at how I should pass the wrapper into my class that uses that object. Obviously that object needs to be polymorphic, so I can't pass it by value, forcing me to pass a pointer. That in and of itself is not a problem, but I'm confused as to who should own the pointer to the class wrapping the API. So... how should I pass the wrapper class into the real class to facilitate mocking?

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  • Silverlight Project - Setting Reference to Copy Local false not working.

    - by cmaduro
    Why is it that when my Silverlight project is built, the output directory contains a bunch of culture specific directories: ar\System.Windows.Controls.resources.dll bg\System.Windows.Controls.resources.dll ca\System.Windows.Controls.resources.dll etc etc etc Also the root of the build output contains: System.Xml.Linq.dll System.windows.Controls.dll I have gone through the projects in my solution and made sure that "Copy Local" is set to false for all the referances of the mentioned dll files. Those 2 files were set to true, but I did switch them to false. Despite my effort to google an answer, I remain stuck.

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  • Exception with Subsonic 2.2, SQLite and Migrations

    - by Holger Amann
    Hi, I'm playing with Migrations and created a simple migration like public class Migration001 : Migration { public override void Up() { TableSchema.Table testTable = CreateTableWithKey("TestTable"); } public override void Down() { } } after executing sonic.exe migrate I'm getting the following output: Setting ConfigPath: 'App.config' Building configuration from c:\tmp\MigrationTest\MigrationTest\App.config Adding connection to SQLiteProvider Found 1 migration files Current DB Version is 0 Migrating to 001_Init (1) There was an error running migration (001_Init): SQLite error near "IDENTITY": syntax error Stack Trace: at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] argum ents, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] argume nts, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwn er) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invoke Attr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisib ilityChecks) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invoke Attr, Binder binder, Object[] parameters, CultureInfo culture) at SubSonic.CodeRunner.RunAndExecute(ICodeLanguage lang, String sourceCode, S tring methodName, Object[] parameters) in D:\@SubSonic\SubSonic\SubSonic.Migrati ons\CodeRunner.cs:line 95 at SubSonic.Migrations.Migrator.ExecuteMigrationCode(String migrationFile) in D:\@SubSonic\SubSonic\SubSonic.Migrations\Migrator.cs:line 177 at SubSonic.Migrations.Migrator.Migrate() in D:\@SubSonic\SubSonic\SubSonic.M igrations\Migrator.cs:line 141 Any hints?

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  • How can I stop Silverlight DataForm immediately saving changes back to underlying object?

    - by Simon_Weaver
    I have a Silverlight master-details DataForm where the DataForm represents a street address. When I edit the Address1 textbox, the value gets automatically committed to the bound Address object once focus leaves the textbox. If I hit the Cancel button, then any changes are undone because Address implements IEditableObject and saves its state. The problem is that since any change is immediately propagated to the underlying object it will be shown in the master grid before the user has actually hit Save. I also have other locations where this data is shown. This is not a very good user experience. I've tried OneWay binding but then I can't commit back without manually copying all the fields over. The only thing I can think of doing is to create a copy of the data first or using OneWay binding, but they both seem a little clumsy. Does DataForm support this way of working?

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  • WPF binding and pointers

    - by Eran
    hey guys, I have a WPF application that contains windows with few user controls and Coordinator object. the window and all its user controls pointing to an object, which instace is in the Coordinator, by thier DataContext. the problem is that I want to change this object (e.g. create new object()) in the Coordinator but I want all the dataContexts to point to the new object. I tried to send the object by ref to the window constructor but it didn't help. any idea about how can I rewrite the memory location that all pointers are pointing to? (I don't want to repalce the properties in object since its a lot of work nor to use a middle object that points to the replaced object) Thanks Eran

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  • Android: howto parse URL String with spaces to URI object?

    - by Mannaz
    I have a string representing an URL containing spaces and want to convert it to an URI object. If is simple try to do String myString = "http://myhost.com/media/mp3s/9/Agenda of swine - 13. Persecution Ascension_ leave nothing standing.mp3"; URI myUri = new URI(myString); it gives me java.net.URISyntaxException: Illegal character in path at index X where index X is the position of the first space in the URL string. How can i parse myStringinto a URI object?

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  • How do I manage disposing an object when I use IoC?

    - by Aval
    How do I manage disposing an object when I use IoC? My case it is Ninject. // normal explicit dispose using (var dc = new EFContext) { } But sometimes I need to keep the context longer or between function calls. So I want to control this behavior through IoC scope. // if i use this way. how do i make sure object is disposed. var dc = ninject.Get<IContext>() // i cannot use this since the scope can change to singleton. right ?? using (var dc = ninject.Get<IContext>()) { } Sample scopes Container.Bind<IContext>().To<EFContext>().InSingletonScope(); Container.Bind<IContext>().To<EFContext>().InRequestScope();

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  • Does binarywriter.flush() also flush the underlying filestream object?

    - by jacob sebastian
    I have got a code snippet as follows: Dim fstream = new filestream(some file here) dim bwriter = new binarywriter(fstream) while not end of file read from source file bwriter.write() bwriter.flush() end while The question I have is the following. When I call bwriter.flush() does it also flush the fstream object? Or should I have to explicitly call fstream.flush() such as given in the following example: while not end of file read from source file bwriter.write() bwriter.flush() fstream.flush() end while A few people suggested that I need to call fstream.flush() explicitly to make sure that the data is written to the disk (or the device). However, my testing shows that the data is written to the disk as soon as I call flush() method on the bwriter object. Can some one confirm this?

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  • Extending User object in Django: User model inheritance or use UserProfile?

    - by Chris
    To extend the User object with custom fields, the Django docs recommend using UserProfiles. However, according to this answer to a question about this from a year or so back: extending django.contrib.auth.models.User also works better now -- ever since the refactoring of Django's inheritance code in the models API. And articles such as this lay out how to extend the User model with custom fields, together with the advantages (retrieving properties directly from the user object, rather than through the .get_profile()). So I was wondering whether there is any consensus on this issue, or reasons to use one or the other. Or even what the Django team currently think?

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  • Best Practice: QT4 QList<Mything*>... on Heap, or QList<Mything> using reference?

    - by Mike Crowe
    Hi Folks, Learning C++, so be gentle :)... I have been designing my application primarily using heap variables (coming from C), so I've designed structures like this: QList<Criteria*> _Criteria; // ... Criteria *c = new Criteria(....); _Criteria.append(c); All through my program, I'm passing pointers to specific Criteria, or often the list. So, I have a function declared like this: QList<Criteria*> Decision::addCriteria(int row,QString cname,QString ctype); Criteria * Decision::getCriteria(int row,int col) which inserts a Criteria into a list, and returns the list so my GUI can display it. I'm wondering if I should have used references, somehow. Since I'm always wanting that exact Criteria back, should I have done: QList<Criteria> _Criteria; // .... Criteria c(....); _Criteria.append(c); ... QList<Criteria>& Decision::addCriteria(int row,QString cname,QString ctype); Criteria& Decision::getCriteria(int row,int col) (not sure if the latter line is syntactically correct yet, but you get the drift). All these items are specific, quasi-global items that are the core of my program. So, the question is this: I can certainly allocate/free all my memory w/o an issue in the method I'm using now, but is there are more C++ way? Would references have been a better choice (it's not too late to change on my side). TIA Mike

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  • Why eGet() in EMF returns Object rather than EObject?

    - by Gabriel Šcerbák
    I am working on some code using the EMF framework in Java, but it is really hard to use, e.g. I cannot implement OCL-like query API on top of EMF which would be type-safe. One of the reasons is that eGet() for a EStructuralFeature return just an Object, not EObject. So anything I would write must use much of null checking, type checking and type casting which is unsafe, not performant and cannot be generalized in a reusable way. Why doesn't EMF generate dummy implementations with EObject wrappers for arbitrary Object value? Implementing the EObject and hence the EClass interfaces even with simple throw UnsupportedOperationException is really a pain (the APIs are too big). The same holds for the eContainer() method which makes navigatinng the model upwards painful.

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  • Is it possible to reference the Azure SDK 1.1 Microsoft.WindowsAzure.* assemblies from a .NET 4.0 Cl

    - by tjrobinson
    I have a WPF application targetting the .NET 4.0 Client Profile which needs to use the Microsoft.WindowsAzure.* assemblies provided in the Windows Azure SDK 1.1. The problem is that these assemblies have a runtime version of v2.0.50727. I am able to add references to them from my WPF project but they're not recognised. I've read about the side by side execution capabilities of .NET 4.0 but does this require both the .NET 2.0 and the .NET 4.0 frameworks to be installed? Is there anything from Microsoft on when a new SDK might be available that contains assemblies targeting .NET 4.0?

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  • Dynamic Linq help, different errors depending on object passed as parameter?

    - by sah302
    I have an entityDao that is inherbited by everyone of my objectDaos. I am using Dynamic Linq and trying to get some generic queries to work. I have the following code in my generic method in my EntityDao : public abstract class EntityDao<ImplementationType> where ImplementationType : Entity { public ImplementationType getOneByValueOfProperty(string getProperty, object getValue){ ImplementationType entity = null; if (getProperty != null && getValue != null) { LCFDataContext lcfdatacontext = new LCFDataContext(); //Generic LINQ Query Here entity = lcfdatacontext.GetTable<ImplementationType>().Where(getProperty + " =@0", getValue).FirstOrDefault(); //.Where(getProperty & "==" & CStr(getValue)) } //lcfdatacontext.SubmitChanges() //lcfdatacontext.Dispose() return entity; } }         Then I do the following method call in a unit test (all my objectDaos inherit entityDao): [Test] public void getOneByValueOfProperty() { Accomplishment result = accomplishmentDao.getOneByValueOfProperty("AccomplishmentType.Name", "Publication"); Assert.IsNotNull(result); } The above passes (AccomplishmentType has a relationship to accomplishment) Accomplishment result = accomplishmentDao.getOneByValueOfProperty("Description", "Can you hear me now?"); Accomplishment result = accomplishmentDao.getOneByValueOfProperty("LocalId", 4); Both of the above work Accomplishment result = accomplishmentDao.getOneByValueOfProperty("Id", New Guid("95457751-97d9-44b5-8f80-59fc2d170a4c"))       Does not work and says the following: Operator '=' incompatible with operand types 'Guid' and 'Guid Why is this happening? Guid's can't be compared? I tried == as well but same error. What's even moreso confusing is that every example of Dynamic Linq I have seen simply usings strings whether using the parameterized where predicate or this one I have commented out: //.Where(getProperty & "==" & CStr(getValue)) With or without the Cstr, many datatypes don't work with this format. I tried setting the getValue to a string instead of an object as well, but then I just get different errors (such as a multiword string would stop comparison after the first word). What am I missing to make this work with GUIDs and/or any data type? Ideally I would like to be able to just pass in a string for getValue (as I have seen for every other dynamic LINQ example) instead of the object and have it work regardless of the data Type of the column.

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  • Is it possible to connect slots of a model object to the GUI in QT4 -Designer?

    - by Robert0
    So I try to build a Model-View window using QTDesigner and C++. For that reason I created a QOBject derived class as my model. It provides slots and signals to access it like: setFileName(QString) or fileNameChanged(QString). I got a little into using signal drag and drop in QTDesigner and found it quite VA-Smalltalk-Like nice. After a while I was wondering if I could also connect my model to this. So is it possible to somehow introduce my model object into the Window/GUI and let QTDesigner connect signals and slots from the model object to the GUI. In essence: Write for me: connect( model, SIGNAL(fileNameChanged(QString)), ui->labelFn, SLOT(setText(QString))) connect( ui-textEdit2, SIGNAL(textChanged(QString)), model, SLOT(setFileName(QString))) Thanks for explaining

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  • iphone, get the object count without performing a fetch?

    - by Andrew
    Hi, I seem to recall that it's possible to return the resulting object count from an NSPredicate in CoreData without actually performing a fetch, but I can't find any reference to this. Can someone confirm that I wasn't dreaming (sad dream to have!), and would this be safe to do in another thread? Thanks Andy

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  • Can Automapper populate a strongly typed object from the data in a NameValueCollection?

    - by Seth Petry-Johnson
    Can Automapper map values from a NameValueCollection onto an object, where target.Foo receives the value stored in the collection under the "Foo" key? I have a business object that stores some data in named properties and other data in a property bag. Different views make different assumptions about the data in the property bag, which I capture in page-specific view models. I want to use AutoMapper to map both the "inherent" attributes (the ones that always exist) as well as the "dynamic" attributes (the ones that vary per view and may or may not exist).

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