static-methods

问题 I've been trying to pickle an object which contains references to static class methods. Pickle fails (for example on module.MyClass.foo ) stating it cannot be pickled, as module.foo does not exist. I have come up with the following solution, using a wrapper object to locate the function upon invocation, saving the container class and function name: class PicklableStaticMethod(object): """Picklable version of a static method. Typical usage: class MyClass: @staticmethod def doit(): print "done"

问题 Can someone please explain how the following syntax works? public static <K, V> HashMap<K, V> getMap(){ return new HashMap<K, V>(); } As in, if this method was implemented in a non instantiable util class of my own this can be used as a static factory method to create map instances, right? Map<Integer, String> myMap = MyUtil.getMap(); would then return a new HashMap with Integer keys and String values for its entries, am I right? If so, how are the types of the key and entry of map being

问题 I am wondering do all the local variables become static if we declare them in a static method ? for example: public static void A(){ int x [] = {3,2}; changeX(x); for (int i = 0; i< x.length; i++){ System.out.println(x[i]); // this will print -1 and 1 } } private static void changeX(int[] x){ x[0] = -1; x[1] = 1; } As far as I understand that Java is pass by value always, but why the state of X has changed after we made the changeX call ? Can anyone explain that please ? and can anyone

问题 Are static methods in Java always resolved at compile time? 回答1: Yes, it is thoroughly investigated and explained in this thread on Sun's forums: New To Java - No late binding for static methods Several quotes: When the compiler compiles that class it decides at compile time which exact method is called for each static method call (that's the big difference to non-static method calls: the exact method to be called is only decided at runtime in those cases). Calling static methods only ever

问题 Currently using a large platform in PHP. The server it's hosted on has recently been upgraded to PHP 5.4. Since, I've received many error messages like: [Sat May 26 19:04:41 2012] [error] PHP Strict Standards: Non-static method Config::getData() should not be called statically, assuming $this from incompatible context in /xxx/Config.inc.php on line 35 The example method is defined as (note the lack of 'static' keyword): function &getData() { $configData =& Registry::get('configData', true,

问题 Say, I have a reference to a Class object with SomeType having a static method. Is there a way to call that method w/o instantiating SomeType first? Preferably not escaping strong typing. EDIT: OK, I've screwed up. interface Int{ void someMethod(); } class ImplOne implements Int{ public void someMethod() { // do something } } Class<? extends Int> getInt(){ return ImplOne.class; } In this case someMethod() can't be static anyways. 回答1: A static method, by definition, is called on a class and

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed last year . I'm reading Programming Scala. At the beginning of chapter 4, the author comments that Java supports static methods, which are "not-so-pure OO concepts." Why is this so? 回答1: One reason that static methods aren't very OO that hasn't been mentioned so far is that interfaces and

问题 I've just recently started my intermediate course in C# programming and I'm learning how to create multiple classes and creating methods to use in my program. It's a very new topic to me so I apologize if it's something very obvious or stupid. I am getting below message in all of my methods: Cannot access static method in non-static context Code in method class: public static int Add(params int[] numbers) { var sum = 0; foreach (var n in numbers) { sum += n; } return sum; } public static int

问题 I've just recently started my intermediate course in C# programming and I'm learning how to create multiple classes and creating methods to use in my program. It's a very new topic to me so I apologize if it's something very obvious or stupid. I am getting below message in all of my methods: Cannot access static method in non-static context Code in method class: public static int Add(params int[] numbers) { var sum = 0; foreach (var n in numbers) { sum += n; } return sum; } public static int

问题 EDIT: Really sorry, I mean Java! As for what I think, I would say the first contains if statement is for s == null or length 0, but I'm confused as to what to put in the return spaceCount(s.substring(1, ......)) + ......; part. I'm trying to use some if statements to write a function that takes a string as a parameter and recursively coutns the number of blanks spaces " " it has. So far I have public static int spaceCount (string s) { if ( ...... ) { return 0; } char c = s.charAt(0); if (....