locking

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I'm reading the Book Java Concurrency in Practice . In chapter 15, they are talking about the nonblocking algorithms and the compare-and-swap (CAS) method. It is written that CAS perform much better than the locking methods. I want to ask the people who already worked with both of these concepts and would like to hear when you are preferring which one of these concepts? Is it really so much faster? For me, the usage of locks is much clearer and easier to understand and maybe even better to maintain (please correct me if I am wrong) . Should

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Wondering if there’s a plugin or best way of setting up an ActiveRecord class so that, for example, when a record enter the "published" state, certain attributes are frozen so that they could not be tampered with. 回答1: You can freeze an entire AR::B object by setting @readonly to true (in a method), but that will lock out all attributes. The way I would recommend is by defining attribute setter methods that check for the current state before passing to super: class Post < ActiveRecord::Base def author=(author) super unless self.published?

In a Java threaddump I found the following: "TP-Processor184" daemon prio=10 tid=0x00007f2a7c056800 nid=0x47e7 waiting for monitor entry [0x00007f2a21278000] java.lang.Thread.State: BLOCKED (on object monitor) at org.apache.jackrabbit.core.state.SharedItemStateManager.getNonVirtualItemState(SharedItemStateManager.java:1725) - locked <0x0000000682f99d98> (a org.apache.jackrabbit.core.state.SharedItemStateManager) at org.apache.jackrabbit.core.state.SharedItemStateManager.getItemState(SharedItemStateManager.java:257) "TP-Processor137" daemon prio=10 tid=0x00007f2a7c00f800 nid=0x4131 waiting for

How Should I Request a Non-Blocking Lock? Why doesn't Ruby's File#flock work as expected when separate attempts are made to lock a file? Locking the file in a block is not the correct solution for this issue because the point is to show the behavior of locking on persistent locks. Using File#flock inside a block releases the lock when the block exits, so it doesn't demonstrate the problem properly. File#flock fails in a variety of ways, especially when requesting a non-blocking lock. Some examples follow. Failing Examples with File#flock Infinite wait when using multiple exclusive locks, since

I'm receiving an incoming C2DM notification while the screen is locked. I'd like to wake up the screen and display the notification message on top of the lock screen using an Activity. I'm launching the notification Activity from my C2DM BroadcastReceiver as follows: Intent new_intent= new Intent().setClass( context, EIAlertDialog.class ); new_intent.addFlags( Intent.FLAG_ACTIVITY_CLEAR_TOP ); new_intent.addFlags( Intent.FLAG_ACTIVITY_NEW_TASK ); context.startActivity( new_intent ); and within the notification Activity's onCreate method, I wake up the screen as follows: PowerManager

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: lock(dictionaryX) { dictionaryX.TryGetValue(key, out value); } is locking necessary while doing lookups to a Dictionary ? THe program is multithreaded, and while adding key/value to dict. dict is being locked. 回答1: Locking is only needed when you are synchronizing access to a resource between threads. As long as there are not mulitple threads involved then locking is not needed here. In the context of updating and reading the value from multiple threads, yes a lock is absolutely necessary. In fact if you're using 4.0 you should consider