The design principles and implementation methods of the POJO MVCC framework in the Java class library
POJO MVCC (PLAIN OELD JAVA Object Multi-Version Concurrency Control) is a multi-version concurrent control framework implemented in the Java library.It is a combination of POJO design principles and MVCC concurrent control theory, and aims to provide a simple and easy -to -use concurrent control solution.
Design Principles:
1. Use POJO principle: POJO refers to ordinary Java objects without any special restrictions or constraints.The design of the POJO MVCC framework should follow the POJO principle as much as possible so that developers can easily integrate and use it.
2. Efficiency: The framework should adopt high -efficiency data structures and algorithms to ensure that it can be quickly and accurately processed in high concurrency conditions.
3. Scalability: The framework should have good scalability, so that developers can customize and expand according to their own needs.
4. Independence: The framework should be independent with the specific business logic, which can be suitable for various application scenarios.
Implementation:
The following is an example of a simple POJO MVCC framework:
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class MVCCFramework<T> {
private Map<Long, T> dataMap;
private Map<Long, Long> versionMap;
private ReadWriteLock lock;
public MVCCFramework() {
dataMap = new HashMap<>();
versionMap = new HashMap<>();
lock = new ReentrantReadWriteLock();
}
public void put(long id, T data) {
lock.writeLock().lock();
try {
dataMap.put(id, data);
versionMap.put(id, System.currentTimeMillis());
} finally {
lock.writeLock().unlock();
}
}
public T get(long id) {
lock.readLock().lock();
try {
return dataMap.get(id);
} finally {
lock.readLock().unlock();
}
}
public T get(long id, long version) {
lock.readLock().lock();
try {
Long dataVersion = versionMap.get(id);
if (dataVersion != null && dataVersion <= version) {
return dataMap.get(id);
}
return null;
} finally {
lock.readLock().unlock();
}
}
public long getVersion(long id) {
lock.readLock().lock();
try {
return versionMap.getOrDefault(id, 0L);
} finally {
lock.readLock().unlock();
}
}
}
In the above example, the MVCCFRAMEWORK class is the core implementation of the POJO MVCC framework.It uses a data Map (DataMap) and a version of Map (VersionMap) to store data objects and version information.Readwritelock is used to provide data on the compilation of data.The put () method is used to store data objects and version information into the corresponding MAP. The get () method is used to obtain data objects based on the ID. The get () method can also obtain the data object according to the specified version.Get the version information of the data object of the specified ID.
When using this framework, developers can store any type of data objects into the framework as needed, and read and control access to the read and control according to the ID and version number.For example:
MVCCFramework<String> framework = new MVCCFramework<>();
framework.put(1L, "Hello");
framework.put(2L, "World");
System.out.println (framework.get (1L)); // Output: Hello
System.out.println (framework.get (2L)); // Output: World
System.out.println (Framework.getVersion (1L)); // Output: The number of milliseconds in the current time
System.out.println (Framework.getVersion (2L)); // Output: milliseconds in the current time
The above example demonstrates how to store and read the data object of String type and output its version information.Developers can store any type of data objects into the frame according to their needs and implement custom concurrent access control strategies.
