getter

I'm trying to use Python's @property decorator on a dict in a class. The idea is that I want a certain value (call it 'message') to be cleared after it is accessed. But I also want another value (call it 'last_message') to contain the last set message, and keep it until another message is set. In my mind, this code would work: >>> class A(object): ... def __init__(self): ... self._b = {"message": "", ... "last_message": ""} ... @property ... def b(self): ... b = self._b ... self._b["message"] = "" ... return b ... @b.setter ... def b(self, value): ... self._b = value ... self._b["last_message"

class a { get b() { delete this.b; return this.b = 1; } } var c = { get b() { delete this.b; return this.b = 1; } } console.log(c.b); // works as expected console.log((new a()).b); // throws error The above code should work fine but the last line throws. Uncaught TypeError: Cannot set property b of # which has only a getter(…) Clearly the getter is not being deleted in class whereas it works fine in object. I am on latest stable chrome. Lazy Getter MDN Entry The getter of the class sits on the .prototype object, not on this , that's why your attempt to delete it fails (and, as Jeremy points

Is there a way to get a get/set behaviour on an array? I imagine something like this: var arr = ['one', 'two', 'three']; var _arr = new Array(); for (var i = 0; i < arr.length; i++) { arr[i].__defineGetter__('value', function (index) { //Do something return _arr[index]; }); arr[i].__defineSetter__('value', function (index, val) { //Do something _arr[index] = val; }); } Array access is no different to normal property access. array[0] means array['0'] , so you can define a property with name '0' and intercept access to the first array item through that. However, that does make it impractical for

Related to a previous example, i tried to monitor my get/set methods on the server (when they are called, and how often). So, my actual been look such : @ManagedBean(name="selector") @RequestScoped public class Selector { @ManagedProperty(value="#{param.profilePage}") private String profilePage; public String getProfilePage() { if(profilePage==null || profilePage.trim().isEmpty()) { this.profilePage="main"; } System.out.println("GET "+profilePage); return profilePage; } public void setProfilePage(String profilePage) { this.profilePage=profilePage; System.out.println("SET "+profilePage); } }