AsyncQueryRunner Interface

AsyncQueryRunner interface provides a way to execute SQL queries asynchronously in Java applications. This interface is part of the Apache Commons DbUtils library and can be used with any database that supports JDBC.

AsyncQueryRunner extends the QueryRunner interface which provides synchronous SQL query execution methods. Asynchronous variants of these methods are provided by the AsyncQueryRunner interface, allowing for non-blocking SQL queries.

Methods

• Future<Integer> update(DataSource dataSource, String sql, Object... params)

  Executes an SQL statement that updates a database.

  • dataSource - the JDBC DataSource to be used to execute the query
  • sql - the SQL statement to be executed
  • params - the parameters to be set in the SQL statement

  Returns a Future object that holds the update count.

• Future<T> query(DataSource dataSource, String sql, ResultSetHandler<T> rsh, Object... params)

  Executes an SQL query and returns the results.

  • dataSource - the JDBC DataSource to be used to execute the query
  • sql - the SQL statement to be executed
  • rsh - a ResultSetHandler object to convert the result set into an object of type T
  • params - the parameters to be set in the SQL statement

  Returns a Future object that holds the result of type T.

Usage

To use AsyncQueryRunner, create an instance of it and call its methods.

DataSource dataSource = getDataSource(); // obtain a JDBC DataSource
AsyncQueryRunner asyncQueryRunner = new AsyncQueryRunner();
Future<Integer> updateCount = asyncQueryRunner.update(dataSource, "UPDATE users SET name = ? WHERE id = ?", "John", 123);
Future<List<User>> results = asyncQueryRunner.query(dataSource, "SELECT * FROM users", new BeanListHandler<>(User.class));

You can use Future methods to check if the query has completed, retrieve the result or handle any exceptions that occurred during query execution.

try {
    Integer count = updateCount.get(); // waits for the query to finish and retrieves the result
    List<User> users = results.get();
} catch (InterruptedException | ExecutionException e) {
    // handle exception
}

Conclusion

AsyncQueryRunner is a useful interface for running SQL queries asynchronously in Java applications. It allows for non-blocking database queries and provides methods for handling the query results through the use of Future objects.