Dynamic configuration from Java classes to Java Config

[aruld]

I have some configuration which are set by the users using java class. I would like to pass on these configuration to Spring Java Config classes. How do I achieve this in SJC?

For instance, the database configuration is set in the Configuration java class (custom code). I would like to pull the database configuration from this custom class and dynamically pass these parameters to DataSourceConfiguration (SJC).

Appreciate any insight into this.

[Chris Beams]

I believe you've gotten this question answered via other channels - is that right?

[aruld]

Chris,

SystemPropertiesValueSource does not really solve my problem as my application could run within a J2SE/J2EE container, as I do not have control over other libraries within the same JVM could possibly override the system properties.

So, I am looking for some kind of setters on these configuration objects which could be invoked just after context initialization.

Basically, I should be able to set some of the database configuration properties at runtime without using any of the existing properties resolvers (System, Environment).

        JavaConfigApplicationContext context = new JavaConfigApplicationContext(ApplicationConfiguration.class);
        Configuration configuration = new Configuration();//my application config class
        configuration.setDatabaseType("MYSQL");
        configuration.setDriver("com.mysql.jdbc.Driver");
        configuration.setUrl("jdbc:mysql://localhost:3306/sjc");
        configuration.setUsername("root");
        configuration.setPassword("mysql");
        overrideConfiguration(configuration);//this should somehow override the configuration originally initialized by the application context
        DataSource ds = context.getBean(BasicDataSource.class);
        Connection conn = ds.getConnection();

Is it possible to achieve something like this in SJC?

Appreciate your clarification.

Thanks!
Arul

[aruld]

Chris,

I was able to resolve this issue after going through some of the system tests.

Btw, did you had a chance to look in to the code which I submitted for http://jira.springframework.org/browse/SJC-150?

-Arul

[Chris Beams]

Re: SJC-150 - not yet, but I haven't forgotten about it. Thanks again for submitting.

[aruld]

Hi Chris,

I have the following test case which fails to override the bean configuration after context creation. Could you please correct me if I am missing something in my configuration?

import static junit.framework.Assert.assertEquals;
import org.junit.Test;
import org.springframework.config.java.annotation.Bean;
import org.springframework.config.java.annotation.Configuration;
import org.springframework.config.java.context.JavaConfigApplicationContext;
import org.springframework.jdbc.datasource.DriverManagerDataSource;

import javax.sql.DataSource;
import java.sql.Connection;

public class TestConfiguration {

  @Test
  public void testOverrideConfig() throws Exception {
    JavaConfigApplicationContext context = new JavaConfigApplicationContext(DataSourceConfiguration.class);
    //override default configuration
    DefaultConfig customConfig = context.getBean(DefaultConfig.class);
    customConfig.setDriverClass("com.mysql.jdbc.Driver");
    customConfig.setJdbcUrl("jdbc:mysql://localhost/test");
    customConfig.setUser("root");
    customConfig.setPassword("mysql");
    DataSource dataSource = context.getBean(DataSource.class);
    Connection connection = dataSource.getConnection();
    assertEquals("MySQL", connection.getMetaData().getDatabaseProductName());
  }

  @Configuration
  static class DataSourceConfiguration {
    //default driver configuration    
    private String driverClass = "org.hsqldb.jdbcDriver";
    private String jdbcUrl = "jdbc:hsqldb:mem:test";
    private String user = "sa";
    private String password = "";

    @Bean
    public DefaultConfig defaultConfig() {
      DefaultConfig defaultConfig = new DefaultConfig(driverClass, jdbcUrl, user, password);
      return defaultConfig;
    }

    @Bean
    public DataSource dataSource() {
      DriverManagerDataSource dataSource = new DriverManagerDataSource();
      DefaultConfig config = defaultConfig();

      dataSource.setDriverClassName(config.getDriverClass());
      dataSource.setUrl(config.getJdbcUrl());
      dataSource.setUsername(config.getUser());
      dataSource.setPassword(config.getPassword());
      return dataSource;
    }

  }

  static class DefaultConfig {
    private String driverClass;
    private String jdbcUrl;
    private String user;
    private String password;

    DefaultConfig(String driverClass, String jdbcUrl, String user, String password) {
      this.driverClass = driverClass;
      this.jdbcUrl = jdbcUrl;
      this.user = user;
      this.password = password;
    }

    public String getDriverClass() {
      return driverClass;
    }

    public void setDriverClass(String driverClass) {
      this.driverClass = driverClass;
    }

    public String getJdbcUrl() {
      return jdbcUrl;
    }

    public void setJdbcUrl(String jdbcUrl) {
      this.jdbcUrl = jdbcUrl;
    }

    public String getUser() {
      return user;
    }

    public void setUser(String user) {
      this.user = user;
    }

    public String getPassword() {
      return password;
    }

    public void setPassword(String password) {
      this.password = password;
    }

  }
}

Thanks!
Arul

[Chris Beams]

The DataSource bean (like all beans) is eagerly instantiated during the construction of JavaConfigApplicationContext. So, by the time you reset the values in DefaultConfig, it's too late.

You have at least a couple of options.

1) make the DataSource bean @Bean(lazy=Lazy.TRUE).
2) make the DataSource bean @Bean(scope=DefaultScopes.PROTOTYPE)

The second option isn't likely to be viable though - if you have multiple objects depending on DataSource, you'll want them all talking to the same instance, I'm sure.

- C

[aruld]

Thanks Chris.

It worked like a charm as always with SJC

-Arul

[Chris Beams]

great news!

[aruld]

Hi Chris,

This works only if I include DataSourceConfiguration to the JavaConfigApplicationContext. If I include both DataSourceConfiguration and JpaConfiguration, the override does not work. It always falls back to the default datasource.

Here is my configuration classes for your reference.

JpaConfiguration

@Configuration
@AnnotationDrivenTx
@AnnotationDrivenConfig
@Import({DataSourceConfiguration.class})
public abstract class JpaConfiguration extends ConfigurationSupport {

  @ExternalBean
  abstract DataSource dataSource();

  @Bean
  public JpaVendorAdapter jpaVendorAdapter() {
    HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();
    adapter.setShowSql(true);
    adapter.setGenerateDdl(false);
    adapter.setDatabasePlatform("org.hibernate.dialect.MySQLInnoDBDialect");
    return adapter;
  }

  @Bean(lazy = Lazy.TRUE)
  public EntityManagerFactory entityManagerFactory() {
    Properties jpaProperties = new Properties();
    jpaProperties.put("hibernate.dialect", "org.hibernate.dialect.MySQLInnoDBDialect");
    jpaProperties.put("hibernate.show_sql", true);

    LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
    em.setPersistenceUnitName("myPU");
    em.setJpaDialect(jpaDialect());
    em.setJpaProperties(jpaProperties);
    em.setDataSource(dataSource());
    em.setJpaVendorAdapter(jpaVendorAdapter());
    em.setLoadTimeWeaver(loadTimeWeaver());
    return this.getObject(em, EntityManagerFactory.class);
  }

  @Bean
  public JpaDialect jpaDialect() {
    return new HibernateJpaDialect();
  }

  @Bean
  public InstrumentationLoadTimeWeaver loadTimeWeaver() {
    return new InstrumentationLoadTimeWeaver();
  }

  @Bean(lazy = Lazy.TRUE)
  public PlatformTransactionManager transactionManager() {
    JpaTransactionManager txManager = new JpaTransactionManager();
    txManager.setEntityManagerFactory(entityManagerFactory());
    txManager.setJpaDialect(jpaDialect());
    txManager.setDataSource(dataSource());
    return txManager;
  }
}

DataSourceConfiguration

@Configuration
public abstract class DataSourceConfiguration extends ConfigurationSupport {
  @Bean(lazy = Lazy.TRUE)
  public DataSource dataSource() {
    DriverManagerDataSource dataSource = new DriverManagerDataSource();
    CustomConfiguration config = customConfiguration();
    dataSource.setDriverClassName(config.getDriverClass());
    dataSource.setUrl(config.getJdbcUrl());
    dataSource.setUsername(config.getJdbcUsername());
    dataSource.setPassword(config.getJdbcPassword());
    return dataSource;

  }

  @Bean
  public CustomConfiguration customConfiguration() {
    String driverClass = "org.h2.Driver";
    String jdbcUrl = "jdbc:h2:mem:test";
    String user = "sa";
    String password = "";

    CustomConfiguration config = new CustomConfiguration();
    config.setDriverClass(driverClass);
    config.setJdbcUrl(jdbcUrl);
    config.setJdbcUsername(user);
    config.setJdbcPassword(password);
    return config;
  }
}

CustomConfiguration

public class CustomConfiguration {
  private String driverClass;
  private String jdbcUrl;
  private String jdbcUsername;
  private String jdbcPassword;
  //getters/setters omitted
}

Test

  @Test
  public void testOverrideConfig() throws Exception {
    JavaConfigApplicationContext context = new JavaConfigApplicationContext(DataSourceConfiguration.class, JpaConfiguration.class);
    //override default configuration
    CustomConfiguration customConfig = context.getBean(CustomConfiguration.class);
    customConfig.setDriverClass("com.mysql.jdbc.Driver");
    customConfig.setJdbcUrl("jdbc:mysql://localhost/test");
    customConfig.setJdbcUsername("root");
    customConfig.setJdbcPassword("secret");
    DataSource dataSource = context.getBean(DataSource.class);
    Connection connection = dataSource.getConnection();
    assertEquals("MySQL", connection.getMetaData().getDatabaseProductName());

  }

Please clarify this issue.

Thanks!
Arul