The technical principles of the POJO MVCC framework in the Java library analysis

The technical principles of the POJO MVCC framework in the Java library analysis Introduction: MVCC (Multi -version concurrent control) is a database control method for processing concurrent access.POJO (ordinary Java object) refers to a simple Java object, which does not depend on a specific framework or library.The POJO MVCC framework combines the advantages of MVCC and POJO, which is used in concurrent control in the Java class library.This article will analyze the technical principles of the POJO MVCC framework in the Java class library and provide the necessary Java code examples. 1. Overview of the POJO MVCC framework The POJO MVCC framework is a lightweight Java concurrent control framework. By adopting multiple version concurrent control technology, the management of concurrent operation of the Java object is realized.It can provide efficient concurrent control in a multi -threaded environment to ensure the consistency and reliability of the data. Second, multi -version concurrent control technology principles 1. Data version management: In the POJO MVCC framework, each Java object saves multiple versions of data, and each version has a unique identification number (usually an increasing serial number or timestamp).When a thread needs to read or modify the object, it uses the latest version number to access the data of the object to ensure that the data read or modify is the latest. 2. Read operation: When a thread needs to read the object, it obtains the current version of the object.If the version of the current version does not match the version when reading the data, it means that the other threads have modified the object, and the thread needs to re -obtain the latest version of the data.This can avoid reading the expired data and improve the efficiency of concurrent reading. 3. Write operation: When a thread needs to modify the object, it first obtains the current version of the object and creates a new version to save the modified data.In this way, different threads can modify different versions of the same object at the same time and will not affect each other.After the thread is completed, submit the new version of the data and update the current version into a new version. Third, POJO MVCC framework example code Below is a simple example of the Java class, using the POJO MVCC framework for concurrent control: public class Person { private String name; private int age; // Construction method, getter and setter public static void main(String[] args) { // Create a concurrent control object MVCC<Person> mvcc = new MVCC<>(); // The initial version of the creation object Person person = new Person("Alice", 25); long version = mvcc.createVersion(person); // Create concurrent reading thread Thread readerThread = new Thread(() -> { // Obtain the current version of the concurrent control object long currentVersion = mvcc.getCurrentVersion(); // Obtain data from the object according to the version number Person currentPerson = mvcc.getDataByVersion(currentVersion); // Read the object data System.out.println("Name: " + currentPerson.getName() + ", Age: " + currentPerson.getAge()); }); // Create concurrent modification threads Thread writerThread = new Thread(() -> { // Obtain the current version of the concurrent control object long currentVersion = mvcc.getCurrentVersion(); // Obtain data from the object according to the version number Person currentPerson = mvcc.getDataByVersion(currentVersion); // Modify the object data currentPerson.setName("Bob"); currentPerson.setAge(30); // Create a new version and submit a modification long newVersion = mvcc.createVersion(currentPerson); mvcc.commit(newVersion); }); // Starting thread writerThread.start(); readerThread.start(); } } In the above examples, we perform concurrent control operations through the method provided by the MVCC class, using multiple versions of concurrent control technology to ensure the consistency of the concurrent read and write. in conclusion: The POJO MVCC framework achieves efficient concurrent control through multiple versions of concurrent control technology in the Java library, ensuring the consistency and reliability of the data.Developers can use the POJO MVCC framework to process the concurrent operation of the Java object and improve the concurrent performance of the code.