synchronization

Iphone syncing via cable

由 拈花ヽ惹草 提交于 2019-12-13 02:33:58
问题 I've made an IPhone App that communicates to a service by calling a webservice and exchanging data as xml. For this to take place, there should be WIFI access. What I'm trying to do now is to do the same but in places without WIFI access. The only way I can think of doing this would be through the USB cable (dock cable?). Unfortunately, no amount of searching online has revealed a way to do this. Is it even possible? Does anyone know how to do this? Some pointers on at least where to look for

java: adding values to a map by multiple threads (is it possible ?)

由 丶灬走出姿态 提交于 2019-12-13 02:15:11
问题 is it thread safe to add elements to a Map by multiple threads at the same time ? Like if 10 threads add an element to a Map at exactly the same time, is the Map going to have 10 elements or 1 ? UPDATE: I don't need to iterate through this map, all I need is to add, remove and get elements by key 回答1: Check if ConcurrentHashMap fits your case. 回答2: There are several ways to handle this: Use a Hashtable. This isn't generally recommended. Hashtable predates the Java Collections Framework from

SymmetricDS: Which approach should I use to synchronize specific tables?

由 帅比萌擦擦* 提交于 2019-12-13 01:53:25
问题 I'm testing SymmetricDS and I'm having some doubt about which approach I should use to synchronize some specific tables. I have two application, the first is a ERP and the second is a PDV. Some tables can be synchronized to all PDV databases, however, in some tables the row should synchronize to a specific PDV instance: In this diagram, the red rectangles show which table need synchronize, and the green arrow show the column where we can identify which SymmetricDS instance will synchronize.

Use “regular” variable to synchronize threads

由 99封情书 提交于 2019-12-13 01:33:48
问题 If I have only two threads, and I want one of them to wait for the other to reach a certain point, is it safe to do the following: bool wait = true; //Thread 1: while(wait) ; wait = true; //re-arm the signal //Thread 2: /* Preform here the code that needs to complete before Thread 1 continues */ wait = false; Basically, if one thread only writes to it and the other only reads, can there be a problem? I assume a read or a write of a single bool is atomic, and even if not, I don't see how it

Can WaitHandle.WaitOne with ExitContext flag be used without ContextBoundObject class?

由 元气小坏坏 提交于 2019-12-13 00:57:12
问题 MSDN documentation suggests that there may be other ways of using ExitContext flag. See WaitHandle.WaitOne() What other ways are there to enter a non-default context outside of using a ContextBoundObject inherited class? (I can't use ContextBoundObject in my application) 回答1: The clue is in this sentence. Even if you are currently executing a method on a class that does not derive from ContextBoundObject, like String, you can be in a nondefault context if a ContextBoundObject is on your stack

Consistent reading and writing a file in python

由 核能气质少年 提交于 2019-12-12 23:38:03
问题 I'm a Python beginner and facing the following : I have a script periodically reading a settings file and doing something according to those settings . I have another script triggered by some UI that writes the settings file with user input values. I use the ConfigParser module to both read and write the file. I am wondering if this scenario is capable of leading into an inconsistent state (like in middle of reading the settings file, the other script begins writing). I am unaware if there

What effect does the monitor object have in synchronized block?

由 邮差的信 提交于 2019-12-12 20:52:35
问题 After hours of reading i am still struggling to understand what the monitor object exactly does. A demo to show what i mean: public class Demo { public static Bathroom bathroom = new Bathroom(); public static Kitchen kitchen = new Kitchen(); public static void main(String[] args) { (new Thread(new Roommate("bob"))).start(); (new Thread(new Roommate("john"))).start(); (new Thread(new Mom())).start(); } } class Bathroom { public void use(String who) { synchronized (Demo.kitchen) { System.out

What does it mean by “partial ordering” and “total ordering” in the discussion of Lamport's synchronization Algorithm?

由 ぐ巨炮叔叔 提交于 2019-12-12 19:24:57
问题 What I understand is, partial ordering and total ordering are two sets of rules. Partial ordering has Three rules: (1) if a an b are two events in the same process and a comes before b, then a->b. (2) ... (3) ... What is total ordering then? Why are the named so? 回答1: Those names stem form the fact that in a partial order not all elements are comparable while in a total order all elements are comparable: A partial order on the elements of a set is defined by three properties that have to hold

glFenceSync alternative in OpenGL ES 2.0

由 懵懂的女人 提交于 2019-12-12 18:54:07
问题 I see that glFenceSync does not exist in OpenGL ES 2.0, it was added only in OpenGL ES 3.0. Does OpenGL ES 2.0 offer any alternative of syncing between CPU and GPU, aside from the brutal force glFinish ? 回答1: In glext.h . GL_API GLsync glFenceSyncAPPLE(GLenum condition, GLbitfield flags) __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_6_0); I am pretty sure this is what you want. Anyway available only on iOS 6.0 or later. 回答2: You have different calls in OpenGL ES 2.0 that give some insight into

避免过度使用synchronization

由 倾然丶 夕夏残阳落幕 提交于 2019-12-12 17:08:32
【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 避免过度使用synchronization avoid excessive synchronization 避免过度使用synchronization Here is an example,which implements an observable set wrapper.It allow clients to subscribe to notifications when elements are added to the set.this is the Observer pattern. for brevity`s, the class does not provide notifications when elements are removed from the set. 这有一个观察着封装的set，它允许客户端订阅添加元素的通知，为了简介，没有提供移出元素的通知。 Observers subscribe to notifications by invoking the addObserver method and unsubscribe by invoking the removeObserver method. In both cases, an instance of the callback
订阅 synchronization