fair beepi

items can then be used as the final classification result. The detailed algorithm details are as follows:1, input data record, is the attribute value of a strip.2, the value of the property to do a number substitution (according to the column from the top down to find the attribute value), similar to Apriori in the transaction records.3, according to the transaction record, the Apriori algorithm is calculated and the frequent itemsets are excavated.4, enter the property values of the query, fin

than a sync lock, and it provides a framework for locks that allow for more flexibility in using locks, but it is even more difficult to use.Juc lock in package, including: Lock interface, Readwritelock interface, Locksupport blocking primitives, condition conditions, abstractownablesynchronizer/ Abstractqueuedsynchronizer/abstractqueuedlongsynchronizer three abstract classes, Reentrantlock exclusive locks, Reentrantreadwritelock read and write locks. Since Countdownlatch,cyclicbarrier and sema

Partition Replica Assignment implementation principle and resource isolation scheme: Http://www.cnblogs.com/yurunmiao/p/5550906.htmlFlume filechannel Optimization (extension) Practice Guide:/HTTP// Www.cnblogs.com/yurunmiao/p/5603097.html2. Hadoop yarn Cluster resource management in our Hadoop yarn cluster, the cluster resource Manager uses the Fair Scheduler (Fairscheduler), which divides the resources by business parties and assigns a separate que

isolation scheme: Http://www.cnblogs.com/yurunmiao/p/5550906.htmlFlume filechannel Optimization (extension) Practice Guide:/HTTP// Www.cnblogs.com/yurunmiao/p/5603097.html2. Hadoop yarn Cluster resource management in our Hadoop yarn cluster, the cluster resource Manager uses the Fair Scheduler (Fairscheduler), which divides the resources by business parties and assigns a separate queue to each business party. This queue is associated with a certain

Synchronized keyword combined with the object's monitor, the JVM provides us with a "built-in lock" semantics, the lock is simple, does not require us to care about locking and release the lock process, we only need to tell the virtual machine which code blocks need to lock, other details will be implemented by the compiler and the virtual machine itself.Our "Built-in lock" can be understood as a built-in feature of the JVM, so a significant problem is that it does not support the customization

Features of RPR Technology RPR is a new MAC layer protocol that optimizes data service transmission in a ring structure. It can adapt to multiple physical layers (such as SDH, Ethernet, and DWDM ), it can effectively transmit data, voice, images, and other business types. It integrates the economic, flexible, and scalable features of the Ethernet technology, while absorbing the advantages of 50 ms fast protection of SDH ring network, it also has technical advantages such as automatic network to

synchronized is not available, thread A will need to reapply for the lock at this point. But this creates a problem because thread a already holds the lock on the object and is requesting a lock on the object, so that thread a waits for a lock that will never be acquired. And because synchronized and lock have the ability to be reentrant, so this phenomenon will not occur. 2. Can break lock Interruptible Lock: As the name suggests, is the lock that can be interrupted accordingly. In Java, synch

the lowest ratio; then select one of the jobs in the queue by the following policy: Select by job priority and commit time order, Consider both user resource limits and memory limits.3. Fair Scheduler Fair SchedulerFair scheduling is a method of assigning job resources, which is designed to allow all jobs to acquire equal shared resources on average over time. all jobs have the same resourcesWhen a single

application Wait time limitIn addition to waiting for external notifications, there is another way to avoid deadlocks, which is to wait for a limited time.We can use the Trylock () method to do a time-limited waitif (Lock.trylock (5, Timeunit.seconds)) {}else {}The Trylock () method receives two parameters, one representing the wait length, and the other representing the timing unit.The Reentrantlock.trylock () method can also be run without parameters directly. In this case, the current thread

; Boolean trylock (); Boolean Trylock (long time, Timeunit unit) throws interruptedexception; void unlock (); Condition newcondition ();The Reentrantlock class has a static internal abstract class sync, which inherits the Abstractqueuedsynchronizer class, The Abstractqueuedsynchronizer class inherits from Abstractownablesynchronizer. There are also two static inner classes in the Reentrantlock class, namely Nonfairsync (non-fair lock) and Fair

"not empty", which is more readable (and more efficient) than the implementation of each lock with only one wait setting. Conditionmethods are wait notify notifyAll similar to, and methods, named await , and, respectively, signal signalAll because they cannot overwrite Object the corresponding method.Back to top of pageIt's not fairIf you look at Javadoc, you'll see that ReentrantLock a parameter to the constructor is a Boolean value that allows you to choose whether you want a

The Java.util.concurrent.locks package provides a framework interface and class for lock and wait conditions, unlike built-in synchronization and monitors. The framework allows for more flexibility in using locks and conditions, but at the expense of more difficult syntax.The lock interface supports locking rules that differ in semantics (reentrant, fair, and so on) and can be used in the context of non-blocking structures, including Hand-over-hand an

I. OverviewStructure:Java.lang.Object Java.util.concurrent.locks.ReentrantLockDisclaimer:reentrantlockLockSerializableA reentrant mutex Lock that has the synchronized same basic behavior and semantics as the implicit monitor lock accessed by using methods and statements, but is more powerful.ReentrantLockWill be owned by a thread that has recently successfully acquired the lock and has not released the lock. When a lock is not owned by another thread, the calling lock thread succeeds in acquiri

http://blog.csdn.net/vickyway/article/details/50113429 https://zhuanlan.zhihu.com/p/29227508 Synchronousqueue is a special blocking queue, unlike Linkedblockingqueue, Arrayblockingqueue, and Priorityblockingqueue, which has no capacity inside. Any queue operation needs to wait for the other thread's outbound operations, and vice versa. If the synchronousqueue is used in the producer/consumer model, then the equivalent of the producer and consumer hand trade, that is, if the producer produces a

more than one condition variable associated with it. This simplifies the development of many concurrency algorithms.For example, 条件（Condition） the Javadoc shows an example of a bounded buffer implementation that uses two condition variables, "not full" and "not empty", which is more readable (and more efficient) than the implementation of each lock with only one wait setting. Conditionmethods are wait notify notifyAll similar to, and methods, named await , and, respectively, signal signalAll be

not possible because synchronized and lock have reentrant features.2. Interruptible LockInterruptible Lock: As the name implies, is a lock that can be broken accordingly.In Java, synchronized is not an interruptible lock, and lock is an interruptible lock.If a thread A is executing the code in the lock, and another threads B is waiting to acquire the lock, it may be because the wait time is too long, and the other thing is not waiting, and we can let it break itself or interrupt it in another t

The use and principle analysis of Semaphore in JUC, Semaphore is also a Synchronizer in Java, unlike Countdownlatch and cyclebarrier, the internal counter is incremented, so what is the internal implementation of Semaphore? It?The Semaphore semaphore is also a synchronization container in Java, unlike Countdownlatch and Cyclicbarrier, where the counters inside it are incremented. In order to be able to list the internal structure of semaphore, we first need to look at the Semaphore class diagram

very ingenious, for the FIFO queue of various operations in the AQS has been implemented,AQS subclasses generally only need to rewrite tryacquire (int arg) and tryrelease (int ARG) two methods .The realization of ReentrantlockThere is an abstract class sync in Reentrantlock:Private final sync sync; /** * Base of synchronization control for this lock. subclassed * into fair and nonfair versions below. Uses AQS State to * represent the numbe

() { for(intj = 0; J ) {test.increase (); } }}From this code you can see that the re-entry lock has a display of operating procedures compared to synchronized, we need to manually define the verification lock, verify the release lock, but also because of this, the re-entry lock logic control flexibility is better than synchronized.Fair lockIn most cases, lock applications are unfair. If a thread 1 requests lock a first, and then thread 2 also requests lock A, then when lock A is available, w

Reprint Source: http://www.cnblogs.com/lxmyhappy/p/7380073.html1. What are the locks inJava ? Fair Lock / non-fair lock Can be re-entered lock Exclusive lock / share lock Mutex / read/write lock optimistic lock / pessimistic lock Segmented lock bias Lock / Lightweight lock / heavyweight Lock Spin lock Java implements the lock has two kinds of syntax, one is the syn