singleton

问题 A day ago my application was one EAR, containing one WAR, one EJB JAR, and a couple of utility JAR files. I had a POJO singleton class in one of those utility files, it worked, and all was well with the world: EAR |--- WAR |--- EJB JAR |--- Util 1 JAR |--- Util 2 JAR |--- etc. Then I created a second WAR and found out (the hard way) that each WAR has its own ClassLoader, so each WAR sees a different singleton, and things break down from there. This is not so good. EAR |--- WAR 1 |--- WAR 2 |-

问题 So there's this so-called module pattern for creating singletons with private members: var foo = (function () { var _foo = 'private!'; return { foo: function () { console.log(_foo); }, bar: 'public!' } })(); There's also this method that I found on my own, but haven't seen anything written about: var foo = new function () { var _foo = 'private!'; this.bar = 'public!'; this.foo = function () { console.log(_foo); }; } I'm thinking there must be a reason why nobody writes about this while there

问题 I have created a spring aspect to handle Retry mechanism. I have also created a Retry annotation. Following is the code for Retry annotation and an aspect which processes this annotation. @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.METHOD) public @interface Retry { /** * List of exceptions for which we need to retry method invocation. * * @return Array of classes. */ Class<?>[] exceptions(); /** * Number of retries. Default is 3. * * @return Number of retires. */ int retries()

问题 I have created a spring aspect to handle Retry mechanism. I have also created a Retry annotation. Following is the code for Retry annotation and an aspect which processes this annotation. @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.METHOD) public @interface Retry { /** * List of exceptions for which we need to retry method invocation. * * @return Array of classes. */ Class<?>[] exceptions(); /** * Number of retries. Default is 3. * * @return Number of retires. */ int retries()

问题 I know actionscript does not allowed private contstructor at any time and But if i want to write a sinlgleton class in action script So how to implement it in actionscript. Can anyone provide an sample example of a singleton pattern in actionscript? 回答1: I use something like this: package singletons { [Bindable] public class MySingleton { private static var _instance:MySingleton; public function MySingleton(e:Enforcer) { if(e == null) { throw new Error("Hey! You can't do that! Call

问题 I have some services in my asp.net mvc application that listen for AMQP messages and invoke methods. No controllers depend on this, so it won't get instantiated on its own. I could instantiate it manually, explicitly providing its dependencies with kernel.Get but it feels like I shouldn't have to do that. Can I make Ninject instantiate classes in singleton scope eagerly even when nothing else depends on it? 回答1: You cannot have ninject instantiate stuff in case you don't ask it to instantiate

问题 I'm having trouble in getting the singleton pattern to initialize a instance variable in smalltalk. (here is a link to another implementation for clarification) this is what I have: new ^UniqueInstance ifNil: [UniqueInstance := self basicNew. UniqueInstance: instanceVar := Object new. ]. that last line (UniqueInstance: instanceVar := Object new.) doesn't work, but that's basically what I need to do: instantiate instanceVar as an Object before returning UniqueInstance back to the caller.

问题 I need to execute a function when a variable value changes. I have a singleton class containing a shared variable called labelChange . Values of this variable are taken from another class called Model . I have two VC classes, one of them has a button and a label and the second only a button. When the button in the first VC class is pressed I am updating the label with this func: func updateLabel(){ self.label.text = SharingManager.sharedInstance.labelChange } But I want to call the same

问题 I have following class "Singleton" to handle SQLite connection and to make sure to have 1 instance of connection for whole process/app: public class DBController { private static DBController instance = new DBController(); private static DBHelper dbHelper; public static DBController getInstance() { return instance; } public SQLiteDatabase dbOpen(Context context) { if(dbHelper == null) dbHelper = new DBHelper(context); return dbHelper.getWritableDatabase(); } } And DBHelper class itself:

问题 I have a server side application where clients can request to reload the configuration. If a client request to reload the configuration, this should not be done immediately, but with an delay of 1 minute. If another client also requests to reload the configuration in the same minute, this request should be ignored. My idea is to schedule a task with a ScheduledExecutorService like: ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor(); service.schedule(new