![]() AssertJ - AssertJ provides a rich set of assertions, truly helpful error messages, improves test code readability.Junit - is a simple framework to write repeatable tests.Lombok - is a java library that spicing up your java.Java - is a systems and applications programming language.Tests run: 32, Failures: 0, Errors: 0, Skipped: 0Īlso, if you do package or install goals, the tests launch automatically. FileQueue accepts a generic type of arbitrary length: only batched queue optionĪdd some data to the queue to the end of the queue. the amount of elements in one WAL file. the maximum allowed compressed file's size the place where compressed files stores. the maximum allowed amount of WAL files before compression corruptionHandler( new M圜orruptionHandler()) If 'false' - the previous files will be removed restores from disk or not, during startup. folder( "/folder/where/store/queue/files") the default folder for all queue's files the name of the queue, used in file patterns ![]() NOTICE: you also could instantiate WAL maxCount option and batchSize to Integer.MAX_VALUE and use flush and compress by yourself in fully manual manner. This kind of queue suits well when your need more performant queue and you don't afraid to lose some amount of data, or you are ready to control it your self by periodically invoking the flush method. Writes and reads to/from the disk operations are batched and it boosts the queue's performance, but you always should remember that in case of unexpected crash you could lose your head or tail data. You can specify a batchSize option, which tells to the queue builder how many elements could be store in memory, before writing to the disk. It is the most reliable kind of the FileQueue īatched - a concept of tail and head buffers is present here. It suits for cases, when you don't want to lose your data at all and you don't care about performance. There is no buffers or something in-memory. Synced - every add operation is flushes on disk immediately and every poll reads the items from the disk directly. There are two main FileQueue implementations: close - flushes and closes the files descriptors of the queue. compress - manually compress all WAL-files into a compressed file flush - flushes all this queue's data to the disk diskSize - tells the amount of bytes, which the queue takes on the disk longSize - returns the number of elements in this queue with wide range, than int The differences between the FileQueue and the Java-default interfaces are the following: ![]() When the amount of that files is sufficiently (specified in the config, see below) that files merges to a big compressed file, the next portions of WAL-files to the next compressed-file and etc. The queue data writes on the disk in a small files, named WAL-files. The code above creates synced FileQueue implementation with default config. TransferQueue is a specialized BlockingQueue in which code that adds an element to the queue has the option of waiting (blocking) for code in another thread to retrieve the element.FileQueue queue = FileQueue. SynchronousQueue a simple rendezvous mechanism that uses the BlockingQueue interface.DelayQueue a time-based scheduling queue backed by a heap.PriorityBlockingQueue an unbounded blocking priority queue backed by a heap.ArrayBlockingQueue a bounded FIFO blocking queue backed by an array.LinkedBlockingQueue an optionally bounded FIFO blocking queue backed by linked nodes.This interface is implemented by the following classes: The package contains a set of synchronized Queue interfaces and classes.īlockingQueue extends Queue with operations that wait for the queue to become nonempty when retrieving an element and for space to become available in the queue when storing an element. For ordered traversal, consider using Arrays.sort(pq.toArray()). The iterator provided in method iterator is not guaranteed to traverse the elements of the PriorityQueue in any particular order. PriorityQueue and its iterator implement all of the optional methods of the Collection and Iterator interfaces. If multiple elements are tied for least value, the head is one of those elements ties are broken arbitrarily. The head of the queue is the least element with respect to the specified ordering. The queue retrieval operations poll, remove, peek, and element access the element at the head of the queue. This queue orders elements according to the order specified at construction time, which can be the elements' natural ordering or the ordering imposed by an explicit Comparator. PriorityQueue class is a priority queue based on the heap data structure. General-Purpose Queue ImplementationsĪs mentioned in the previous section, LinkedList implements the Queue interface, providing first in, first out (FIFO) queue operations for add, poll, and so on. The Queue implementations are grouped into general-purpose and concurrent implementations.
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