The design principle of the T Rex framework and its application in the Java class library

T Rex (Template Realization Extensions) framework is a powerful tool for providing templates for Java programmers to achieve expansion functions.It is based on the Java dynamic agency and reflection mechanism, which aims to simplify the writing of universal code and the elimination of repeated code.The T Rex framework depends mainly on two core concepts: template objects and template methods. The design principle of the T Rex framework mainly includes the following aspects: 1. Template object: The T Rex framework creates a template object by creating a set of interfaces or inheriting an abstract class to define the basic structure of the template.The method in the template object can be covered or modified by the quilt class to meet specific business needs. 2. Template method: The template method is the core concept of the T Rex framework. It defines the basic execution process of the template object.The template method can be rewritten by subclasses to achieve specific business logic.In the template method, the T Rex framework provides a series of extension points, which can be used to insert custom logic. 3. Dynamic proxy and reflection mechanism: The T Rex framework uses the Java dynamic proxy and reflection mechanism to achieve dynamic replacement of the template object method.Through dynamic agents, the T Rex framework can generate an agent object during runtime. This object can intercept the call of the template object method and modify the behavior when necessary. The T Rex framework is widely used in the Java library.It can be applied to various scenarios that need to implement template mode, such as: 1. Database operation: In the database operation, the T Rex framework can help developers to achieve some general logic, such as transaction management and connecting pool management.Developers only need to define a template object for a database operation, and then customize the specific SQL query and update operation by implementing the template method. 2. Web framework: In Web development, the T Rex framework can be used to implement the template object of the controller layer.For example, developers can define a template object to process HTTP requests, and implement public logic such as parsing and verification of request parameters in the template method, and authority verification. 3. Message processing: The T Rex framework can be applied to the message processing system, such as consumers in the message queue.Developers can define a template object with a message processing, and then process the specific message logic by implementing the template method. The following is a simple example code that demonstrates the application of the T Rex framework in the database operation: // Define the template object of the database operation interface DatabaseTemplate { <T> T executeQuery(String sql, RowMapper<T> rowMapper); void executeUpdate(String sql); } // Implement the template object class DatabaseTemplateImpl implements DatabaseTemplate { @Override public <T> T executeQuery(String sql, RowMapper<T> rowMapper) { // Execute the SQL query operation, and use Rowmapper to mappart the result as the Java object // ... // omit specific implementation } @Override public void executeUpdate(String sql) { // Execute SQL update operation // ... // omit specific implementation } } // Define the template method class UserDao { private DatabaseTemplate databaseTemplate; public UserDao(DatabaseTemplate databaseTemplate) { this.databaseTemplate = databaseTemplate; } public User findUserById(int id) { String sql = "SELECT * FROM users WHERE id = ?"; return databaseTemplate.executeQuery(sql, new UserRowMapper()); } public void updateUser(User user) { String sql = "UPDATE users SET name = ?, age = ? WHERE id = ?"; databaseTemplate.executeUpdate(sql); } } // Customized mountaineers interface RowMapper<T> { T mapRow(ResultSet rs); } class UserRowMapper implements RowMapper<User> { @Override public User mapRow(ResultSet rs) { // Map the data in ResultSet as a User object // ... // omit specific implementation } } // Example usage DatabaseTemplate databaseTemplate = new DatabaseTemplateImpl(); UserDao userDao = new UserDao(databaseTemplate); User user = userDao.findUserById(1); user.setName("John"); userDao.updateUser(user); In the above example, we first define a database -operated template object `databaseTemplate` and implement two methods of the object's method` executequry` and `ExecuteupDate`.We then define a `UserDao` class. The method in this class complete the database operation by calling the method of the` databaseTemplate` object.Finally, we used the `databaseTemplateimpl` as the implementation class of the template object, and created a` UserDao` object for database operation. In short, the T Rex framework is based on the design principles of template objects and template methods. It is widely used in the Java class libraries that are widely used in various scenarios that need to realize template patterns. It provides convenience of code reuse and expansion, and improves development efficiency.