subclass

问题 Groovy is so powerful I wonder whether there's an easy way to do this. The scenario: I have an abstract class, AbstractSequence . Then I have two (more in reality) subclasses, called say CasedSequence and LowerCaseSequence . Each of these concrete classes has to have an "identity map", i.e. like a Set but where it is possible to extract an element based on functional equality (overriding of equals and hashCode ). So we have: class CasedSequence extends AbstractSequence { static Map

问题 I want to put all attribute names in SubClass to a list, I want to do that in Base class. How can I do that? My method now is: class Base(): def __init__(self): # print SubClass' new attribues' names ('aa' and 'bb' for example) for attr in dir(self): if not hasattr(Base, attr): print attr class SubClass(Base): aa = '' bb = '' is there a better way to do that ? Thanks for any help. 回答1: As the @JohnZwinck suggested in a comment, you're almost certainly making a design mistake if you need to do

问题 I'm trying to center the text in a edit control vertically, after some research I found I have to process the WM_NCCALCSIZE message. So i've subclassed my edit control, but the WM_NCCALCSIZE message is never sent. Am I doing something wrong? EDIT: So i'm processing the WM_NCCALCSIZE message fine, and I have a 3d border created by passing WS_EX_CLIENTEDGE to CreateWindowEx . But if I disable windows themes by killing the theme service, the border goes away on the control thats processing the

问题 I have a method set in my superclass... public void explain() { for (Item item: Instances) { System.out.println(item.getname + " is in location " + item.place): } } I need to override this same method in the subclass to print out the original output message but the new instance for this method needs to print out different values that have been set in the subclass I'm confused with the overriding bit (as I know little about it) and would like an explanation. 回答1: So just give the method in

问题 I've looked around here find an answer to my question and I can't. How do you call a subclass method from a superclass in Java? Basically what I'm looking to do is this: I have a method called exec that takes a String as a parameter for a command. I want to be able to call the exec method in the subclass that the developer has overridden from the superclass without knowing the subclasses name ahead of time. This is like the way the Thread class works. I'm not looking to do what every answer I

问题 I've looked around here find an answer to my question and I can't. How do you call a subclass method from a superclass in Java? Basically what I'm looking to do is this: I have a method called exec that takes a String as a parameter for a command. I want to be able to call the exec method in the subclass that the developer has overridden from the superclass without knowing the subclasses name ahead of time. This is like the way the Thread class works. I'm not looking to do what every answer I

问题 Here's my general problem space: I have a byte/bit protocol with a device over I2C. I've got a "database" of the commands to fully describe all the bitfields types and values and enumerations. I have a class to consume the database and a i2c driver/transactor so that I can then call commands and get responses. MyProtocol = Protocol('database.xml',I2CDriver()) theStatus = MyProtocol.GET_STATUS() creates the proper byte stream for the GET_STATUS command, sends it over the i2c and returns the

问题 Im subclassing parseUser , so when i look for user i use : query.getFirstInBackground(new GetCallback<MySubClass>() { @Override public void done(MySubClass user, ParseException e) { but when i need to user getCurrentUser or logInInBackground i getting ParseUser instead of MySubClass . i user this methods : MySubClass.logInInBackground(userName, "", new LogInCallback() { @Override public void done(ParseUser u, ParseException arg1) { } }); but i want the callback to return MySubClass object

问题 I tried a very simple implementation, like this: @implementation ScrollingTextField - (void)scrollWheel:(NSEvent *)event { self.doubleValue -= event.scrollingDeltaY; } @end I bound the value of the scrolling text field to some other object. Scrolling now updates the visible text on the text field just fine. However, the bound value does not change. Why does the bound value not change? Or: How can I make the bound value recognize the change? 回答1: The bound value doesn't change by Apple's

问题 How do I make the single image uploader do different actions depending on the model it is creating the image for? I have one image uploader, and I want to upload images for Users and for Posts. For the user, I want the original image & thumbnail (70x70). For the Posts, I want the original image and featured thumbnail (260x180). I could just make 3 versions for every image and just call the desired one, but that's probably really bad since it would clog my storage database. I looked at: