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Java leaking this in constructor [duplicate]

吃可爱长大的小学妹 提交于 2019-11-26 13:21:49
This question already has an answer here: Leaking this in constructor warning 10 answers Why do IDE's complain about "leaking this in constructor"? I've always assumed that it's just bad practice. But I actually never found why it is bad. Leaking the this reference in the constructor (not controller) is dangerous, especially in a multithreaded environment. This is because the object is not fully constructed until the constructor call finishes. Leaking this from the constructor thus means that the external world gets access to an object which is not yet fully constructed. This may not

How do I pass the this context to a function?

喜你入骨 提交于 2019-11-26 12:44:22
I thought this would be something I could easily google, but maybe I'm not asking the right question... How do I set whatever "this" refers to in a given javascript function? for example, like with most of jQuery's functions such as: $(selector).each(function() { //$(this) gives me access to whatever selector we're on }); How do I write/call my own standalone functions that have an appropriate "this" reference when called? I use jQuery, so if there's a jQuery-specific way of doing it, that'd be ideal. jAndy Javascripts .call() and .apply() methods allow you to set the context for a function.

Android: why must use getBaseContext() instead of this

落花浮王杯 提交于 2019-11-26 12:36:27
问题 this often to reference to current context. But, at some case, why we must use getBaseContext() instead of this . (It means when use this will notice error). Here is my example: Spinner spinner = (Spinner) findViewById(R.id.spinner); spinner.setAdapter(adapter); spinner.setOnItemSelectedListener(new OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?>arg0, View arg1, int arg2, long arg3){ Toast.makeText(getBaseContext(),\"SELECTED\", Toast.LENGTH_SHORT).show(); /

&#39;this&#39; does not work properly in another event. I&#39;m clueless as to why [duplicate]

﹥>﹥吖頭↗ 提交于 2019-11-26 12:33:23
This question already has an answer here: Javascript “addEventListener” Event Fires on Page Load [duplicate] 2 answers Short story, I don't know why it's not working, I've tried Console.Log() to figure out what 'this' is and the event just keeps passing window. It's a click event that's suppose to activate effects on a certain figure in this carousel, which is why I can't just individually search for class (at least to my knowledge). Any fix from the smarter? var carFigure = null; //----------The Events $('.figure').click(toggleCarousel(this)); //$('.figure').mouseover(stopCarousel(this)); //$

Leaking this in constructor warning

我只是一个虾纸丫 提交于 2019-11-26 12:18:55
I'd like to avoid (most of the) warnings of Netbeans 6.9.1, and I have a problem with the 'Leaking this in constructor' warning. I understand the problem, calling a method in the constructor and passing " this " is dangerous, since " this " may not have been fully initialized. It was easy to fix the warning in my singleton classes, because the constructor is private and only called from the same class. Old code (simplified): private Singleton() { ... addWindowFocusListener(this); } public static Singleton getInstance() { ... instance = new Singleton(); ... } New code (simplified): private

How does require() in node.js work?

我与影子孤独终老i 提交于 2019-11-26 12:06:21
问题 I tried this: // mod.js var a = 1; this.b = 2; exports.c = 3; // test.js var mod = require(\'./mod.js\'); console.log(mod.a); // undefined console.log(mod.b); // 2 console.log(mod.c); // 3, so this === exports? So I image that require() may be implement like this: var require = function (file) { var exports = {}; var run = function (file) { // include \"file\" here and run }; run.apply(exports, [file]); return exports; } Is that right? Please help me to understand require(), or where can I

Why is &#39;this&#39; a pointer and not a reference?

人盡茶涼 提交于 2019-11-26 12:05:02
I was reading the answers to this question C++ pros and cons and got this doubt while reading the comments. programmers frequently find it confusing that "this" is a pointer but not a reference. another confusion is why "hello" is not of type std::string but evaluates to a char const* (pointer) (after array to pointer conversion) – Johannes Schaub - litb Dec 22 '08 at 1:56 That only shows that it doesn't use the same conventions as other (later) languages. – le dorfier Dec 22 '08 at 3:35 I'd call the "this" thing a pretty trivial issue though. And oops, thanks for catching a few errors in my

Java: Class.this

孤人 提交于 2019-11-26 11:56:23
问题 I have a Java program that looks like this. public class LocalScreen { public void onMake() { aFuncCall(LocalScreen.this, oneString, twoString); } } What does LocalScreen.this means in aFuncCall ? 回答1: LocalScreen.this refers to this of the enclosing class. This example should explain it: public class LocalScreen { public void method() { new Runnable() { public void run() { // Prints "An anonymous Runnable" System.out.println(this.toString()); // Prints "A LocalScreen object" System.out

Use of “this” keyword in C++ [duplicate]

自作多情 提交于 2019-11-26 11:52:49
问题 Possible Duplicate: Is excessive use of this in C++ a code smell When should you use the \"this\" keyword in C++? Is there any reason to use this-> In C++, is the keyword this usually omitted? For example: Person::Person(int age) { _age = age; } As opposed to: Person::Person(int age) { this->_age = age; } 回答1: Yes, it is not required and is usually omitted. It might be required for accessing variables after they have been overridden in the scope though: Person::Person() { int age; this->age =

Does using $this instead of $(this) provide a performance enhancement?

淺唱寂寞╮ 提交于 2019-11-26 11:50:36
Assume I have the following example: Example One $('.my_Selector_Selected_More_Than_One_Element').each(function() { $(this).stuff(); $(this).moreStuff(); $(this).otherStuff(); $(this).herStuff(); $(this).myStuff(); $(this).theirStuff(); $(this).children().each(function(){ howMuchStuff(); }); $(this).tooMuchStuff(); // Plus just some regular stuff $(this).css('display','none'); $(this).css('font-weight','bold'); $(this).has('.hisBabiesStuff').css('color','light blue'); $(this).has('.herBabiesStuff').css('color','pink'); } Now, it could be: Example Two $('.my_Selector_Selected_More_Than_One