Data Source

The data-source module provides a flexible way to configure and manage JDBC data sources in light-4j applications. It wraps HikariCP to provide high-performance connection pooling.

Overview

Unlike the simple javax.sql.DataSource configuration in service.yml, the data-source module offers:

• Support for multiple data sources.
• Detailed HikariCP configuration.
• Encrypted password support.
• Separation of concerns (DataSource config vs. Service config).

Dependency

Add the following dependency to your pom.xml:

<dependency>
    <groupId>com.networknt</groupId>
    <artifactId>data-source</artifactId>
    <version>${version.light-4j}</version>
</dependency>
<dependency>
    <groupId>com.zaxxer</groupId>
    <artifactId>HikariCP</artifactId>
</dependency>
<!-- Add your JDBC driver dependency here (e.g., mysql-connector-java, postgresql) -->

Configuration

Configuration is primarily handled in datasource.yml.

datasource.yml

You can define multiple data sources by giving them unique names (e.g., PostgresDataSource, H2DataSource).

# Example Configuration
PostgresDataSource:
  DriverClassName: org.postgresql.ds.PGSimpleDataSource
  jdbcUrl: jdbc:postgresql://postgresdb:5432/mydb
  username: postgres
  # Password can be encrypted using the light-4j decryptor
  password: CRYPT:747372737...
  maximumPoolSize: 10
  connectionTimeout: 30000
  # Optional HikariCP settings
  settings:
    autoCommit: true
  # Optional driver parameters
  parameters:
    ssl: 'false'

H2DataSource:
  DriverClassName: org.h2.jdbcx.JdbcDataSource
  jdbcUrl: jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1
  username: sa
  password: sa

service.yml

You need to register the data sources in service.yml so they can be injected or retrieved via SingletonServiceFactory.

singletons:
  # Register the Decryptor for encrypted passwords
  - com.networknt.utility.Decryptor:
      - com.networknt.decrypt.AESDecryptor

  # Register specific Data Sources
  - com.networknt.db.GenericDataSource:
      - com.networknt.db.GenericDataSource:
          - java.lang.String: PostgresDataSource
      - com.networknt.db.GenericDataSource:
          - java.lang.String: H2DataSource

  # Or specific implementations if available
  - javax.sql.DataSource:
      - com.networknt.db.GenericDataSource::getDataSource:
          - java.lang.String: PostgresDataSource

Usage

Getting a DataSource

You can retrieve the DataSource instance using SingletonServiceFactory.

import com.networknt.service.SingletonServiceFactory;
import com.networknt.db.GenericDataSource;
import javax.sql.DataSource;

public class MyDao {
    public void query() {
        // Option 1: Get the GenericDataSource wrapper
        GenericDataSource genericDs = SingletonServiceFactory.getBean(GenericDataSource.class); 
        // Note: If you have multiple, you might need getBean(Class, name) or check how it's registered.
        
        // Option 2: If registered as javax.sql.DataSource
        DataSource ds = SingletonServiceFactory.getBean(DataSource.class);
        
        try (Connection conn = ds.getConnection()) {
            // ... use connection
        }
    }
}

Multiple Data Sources

If you have multiple data sources, it is best to register them by name in service.yml and retrieve them by name or class if you created specific subclasses.

// Retrieving by name if registered as such (requires custom registration logic or specific class beans)
GenericDataSource postgres = (GenericDataSource) SingletonServiceFactory.getBean("PostgresDataSource");

Features

Encrypted Passwords

You can use the light-4j encryption tool to encrypt database passwords. Prefix the encrypted string with CRYPT: in datasource.yml or secret.yml.

Setting Configuration

The settings map in datasource.yml matches the setXxx methods of HikariDataSource. For example:

settings:
  autoCommit: false
  idleTimeout: 60000