notify

问题 This link http://msdn.microsoft.com/en-us/library/aa772153(VS.85).aspx says: You can register up to five notification requests on a single LDAP connection. You must have a dedicated thread that waits for the notifications and processes them quickly. When you call the ldap_search_ext function to register a notification request, the function returns a message identifier that identifies that request. You then use the ldap_result function to wait for change notifications. When a change occurs,

问题 How can the wait() and notify() methods be called on Objects that are not Threads? That doesn\'t really make sense, does it? Surely, it must make sense, however, because the two methods are available for all Java objects. Can someone provide an explanation? I am having trouble understanding how to communicate between threads using wait() and notify() . 回答1: Locking is about protecting shared data. The lock is on the data structure being protected. The threads are the things accessing the data

问题 If I just use synchronized, not wait/notify method, will it still keep thread-safe ? What\'s the difference ? Thx in advance. 回答1: Using synchronized makes a method / block accessible by only on thread at a time. So, yes, it's thread-safe. The two concepts are combined, not mutually-exclusive. When you use wait() you need to own the monitor on that object. So you need to have synchronized(..) on it before that. Using .wait() makes the current thread stop until another thread calls .notify()

问题 I have 3 threads 1st printing A 2nd printing B 3rd printing C I want to print in sequence A B C A B C A B C and so on..... So I wrote the program below, but I am not able to achieve the same. I am aware of the problem that when status=1 at that time say for example B1 and C1 thread are waiting and when I do notifyAll() both waiting thread wake up and depending on CPU allocation it might print B or C. in this case I want only B to be printed after A. what modification I need to do. public

问题 Why are the wait() and notify() methods declared in the Object class, rather than the Thread class? 回答1: Because, you wait on a given Object (or specifically, its monitor) to use this functionality. I think you may be mistaken on how these methods work. They're not simply at a Thread-granularity level, i.e. it is not a case of just calling wait() and being woken up by the next call to notify() . Rather, you always call wait() on a specific object, and will only be woken by calls to notify on

问题 Say I have a queue full of tasks which I need to submit to an executor service. I want them processed one at a time. The simplest way I can think of is to: Take a task from the queue Submit it to the executor Call .get on the returned Future and block until a result is available Take another task from the queue... However, I am trying to avoid blocking completely. If I have 10,000 such queues, which need their tasks processed one at a time, I\'ll run out of stack space because most of them

问题 Can I get a complete simple scenario i.e. tutorial that suggest how this should be used, specifically with a Queue? 回答1: The wait() and notify() methods are designed to provide a mechanism to allow a thread to block until a specific condition is met. For this I assume you're wanting to write a blocking queue implementation, where you have some fixed size backing-store of elements. The first thing you have to do is to identify the conditions that you want the methods to wait for. In this case,