methods

问题 I am programming a small game for my school assignment, the game is a simple 2D game with monsters, items and bullets. Basically you run around and tries to collect all the item coins, the monsters tries to prevent you and you can shoot them down with the bullets that you collect. Very simple. The question is, i have added the monsters, items, walls, player and bullets to a static class named LiveObjects, these objects can i then access from any place in the code. Is it a bad practice? Whats

问题 This method shall take two objects of the same type and return one of those objects by random: public static <T> T random(T o1, T o2) { return Math.random() < 0.5 ? o1 : o2; } Now, why does the compiler accept two parameters with distinctive types? random("string1", new Integer(10)); // Compiles without errors EDIT: Now that I know that both parameters are getting implicitly upcasted, I wonder why the compiler does complain when calling the following method: public static <T> List<T>

问题 This might just be a question of personal taste and workflow, but in case it's more than that, I feel I should ask anyway. In Java, what differences are there between creating an instance via constructor and via a static method (which returns the instance)? For example, take this bit of code from a project I'm working on (written up by hand at time of posting, so some shortcuts and liberties are taken): Plugin main; Map<int, int> map; public Handler(Plugin main) { this.main = main; } public

问题 This might just be a question of personal taste and workflow, but in case it's more than that, I feel I should ask anyway. In Java, what differences are there between creating an instance via constructor and via a static method (which returns the instance)? For example, take this bit of code from a project I'm working on (written up by hand at time of posting, so some shortcuts and liberties are taken): Plugin main; Map<int, int> map; public Handler(Plugin main) { this.main = main; } public

问题 To be short, suppose I have a string 'next' , next = "123rpq" and I can apply a str method .isdigit() to 'next' . So my question is how to check the implementation of this method. Hence is there a thing like inspect.getsource(somefunction) to get the source code of a 'method'? UPDATE: see comment about variable name 'next' below. 回答1: For modules, classes, functions and a few other objects you can use inspect.getfile or inspect.getsourcefile . However, for builtin objects and methods this

问题 JTable header not showing... My JTable header wont show even if add it into a container like JScrollPane...tell me why is it happen and how can i fix it or debug it.. I search through internet and all they saying is add container to your jtable, i did but still my header are not showing. public void table(){ try{ rs = stat.executeQuery("SELECT * FROM payments;"); Vector<String> header = new Vector<String>(); header.add("PAYMENT"); header.add("AMOUNT"); header.add("MODIFIER"); header.add("DATE

问题 My question: Why is callNextMethod() not passing arguments as expected to the next method? Situation: Say I have two hierarchical classes foo and bar ( bar is subclass of foo ) for which I have a method foobar that can dispatch for both classes (i.e., has methods for both classes). Furthermore, the method for the (sub)class bar calls the method for foo after some calculations with callNextMethod() . Both methods have the same additional argument (with default) that should be passed to the

问题 Are there any plans to implement ruby behavior similar to the CoffeeScript feature of specifying an instance variable name in a method argument list? Like class User def initialize(@name, age) # @name is set implicitly, but @age isn't. # the local variable "age" will be set, just like it currently works. end end I'm aware of this question: in Ruby can I automatically populate instance variables somehow in the initialize method? , but all the solutions (including my own) don't seem to fit the

问题 I want to create a Procedure that its parameter is also a procedure. Is it possible? I created some procedures to be used as parameters below: Private Sub Jump(xStr as string) Msgbox xStr & " is jumping." End Sub Private Sub Run(xStr as string) Msgbox xStr & " is jumping." End Sub this procedure should call the procedure above: Private Sub ExecuteProcedure(?, StringParameter) '- i do not know what to put in there ? ' - name of the procedure with parameter End Sub usage: ExecuteProcedure(Jump,

问题 [].every(i => i instanceof Node) // -> true Why does the every method on arrays in JavaScript return true when the array is empty. I'm trying to do type assertion like so... const isT = (val, str) => typeof val === str const nT = (val, str) => !isT(val, str) const is = {} is.Undef = (...args) => args.every(o => isT(o, 'undefined')) is.Def = (...args) => args.every(o => nT(o, 'undefined')) is.Null = (...args) => args.every(o => o === null) is.Node = (...args) => args.every(o => o instanceof