setter

问题 I need to do some additional stuff in a setter method. But I get an infinite loop when doing so: I've got a core data object @interface Transaction : NSManagedObject @property (nonatomic, retain) NSDate * date; @end @implementation Transaction @dynamic date; -(void)setDate:(NSDate *)date { self.date = date; //additional stuff omitted } So, in that case I get an infinite loop. Okay so I searched on the net and modified my code in the following way and for every version I get compiler errors

问题 I have been searching for this online, but I can't seem to find something that is clear enough for me to understand. I have seen "similiar" questions on here about this in Java. class animal{ private $name; // traditional setters and getters public function setName($name){ $this->name = $name; } public function getName(){ return $this->name; } // animal constructors function __construct(){ // some code here } // vs function __construct($name){ $this->name = $name; echo $this->name; } } $dog =

问题 In short, when the property value changing, I have to update some logic in my code, for example: - (void)setProp:(NSString *)theProp { if (prop != theProp){ [prop release]; prop = [theProp copy]; [self myLogic]; } } or: - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { if ([keyPath isEqualToString:@"prop"]){ [self myLogic]; } } Which is the best way, and WHY? EDIT: I prefect the second way, because I don't know what

问题 I have a bean: <bean id="BasketLogic" class="efco.logic.EfcoBasketLogic" autowire="byType"> <property name="documentLogic" ref="DocumentLogic" /> <property name="stateAccess" ref="StateAccess" /> <property name="contextAccess" ref="ContextAccess" /> </bean> <bean id="EfcoErpService" autowire="byType" class="efco.erp.service.EfcoErpServiceImpl"> <constructor-arg ref="ErpConnector"/> </bean> documentLogic , stateAccess and contextAccess are fields on BasketLogicImpl And I do not have <context

问题 The code is from Stanford CS193p. I added a NSLog to check it out. The label seems not being initialized. Any idea? @interface AskerViewController() <UITextFieldDelegate> @property (weak, nonatomic) IBOutlet UILabel *questionLabel; @property (weak, nonatomic) NSString *question; @end @implementation AskerViewController @synthesize questionLabel = _questionLabel; @synthesize question = _question; - (void)setQuestion:(NSString *)question { _question = question; self.questionLabel.text =

问题 Consider the following code: var x = 0; var o = {}; function getter() { return x; } Object.defineProperty(o, "y", { get: getter, set: function (y) { x = y; Object.defineProperty(o, "y", { get: getter }); }, configurable: true }); My objective is to remove the setter and make the property o.y non-configurable after the setter has been called once. However it doesn't work as expected: > x // 0 > o.y // 0 > o.y = 1 // 1 > x // 1 > o.y // 1 > o.y = 2 // 2 > x // 2 > o.y // 2 So my code did not

问题 Looking for guidance on where to place code which is dependent upon changes to a property. For example, I have a view model which is used to hold state for an applications settings public SettingsViewModel(ISettingsRepository settings) { _settings = settings; // ... } For each change to a settings property we have to persist this change to the repository, and on some properties, other properties are affected, so additional code is required. I started off just adding this logic to the setter

问题 I am not familiar with templates, but I wonder, if it is possible to use them for setter and getter methods. For example in this situation: double exmlClass::getA(void) const { return a_; } void exmlClass::setA(const double& a) { a_ = a; } double exmlClass::getB(void) const { return b_; } As you can see, methods are almost the same, except they refer to another private variables (a_, b_, c_). Is there a more elegant way to write those functions or it is common practice to do like above in

问题 I have a base class with a property which has a setter method. Is there a way to invoke the setter in the base class from a derived class and add some more functionality to it just like we do with overriden methods using the base keyword. Sorry I should have added an example. Here is an example. Hope I get it right: public class A { public abstract void AProperty { set { // doing something here } } } public class B : A { public override void AProperty { set { // how to invoke the base class

问题 I have a base class with a property which has a setter method. Is there a way to invoke the setter in the base class from a derived class and add some more functionality to it just like we do with overriden methods using the base keyword. Sorry I should have added an example. Here is an example. Hope I get it right: public class A { public abstract void AProperty { set { // doing something here } } } public class B : A { public override void AProperty { set { // how to invoke the base class