I have multiple similar configuration classes in my project.

@Configuration
public class configA {
  private final static String CONFIG_STRING = "configA";

  @Bean( name = "first"   CONFIG_STRING )
  public First first() {
    ...
  }

  @Bean( name = "second"   CONFIG_STRING )
  public Second second() {
    ...
  }
}

@Configuration
public class configB {
  private final static String CONFIG_STRING = "configB";

  @Bean( name = "first"   CONFIG_STRING )
  public First first() {
    ...
  }

  @Bean( name = "second"   CONFIG_STRING )
  public Second second() {
    ...
  }
}

They're all the same, only the CONFIG_STRING is different.

Can I refactor those classes?

CodePudding user response：

You can use Template Method in order to let subclasses override specific steps of the algorithm without changing its structure.

Here is an example below. If there is a method that keeps the shared behaviour, this approach would also be a good option.

BaseConfig:

@Configuration
public abstract class BaseConfig {

    protected abstract String first();

    protected abstract String second();
}

ConfigA:

@Configuration
public class ConfigA extends BaseConfig {

    private final static String CONFIG_STRING = "configA";

    @Override
    @Bean( name = "first"   CONFIG_STRING )
    protected String first() {
        return CONFIG_STRING;
    }

    @Override
    @Bean( name = "second"   CONFIG_STRING )
    protected String second() {
        return CONFIG_STRING;
    }
}

ConfigB:

@Configuration
public class ConfigB extends BaseConfig {

    private final static String CONFIG_STRING = "configB";

    @Override
    @Bean( name = "first"   CONFIG_STRING )
    protected String first() {
        return CONFIG_STRING;
    }

    @Override
    @Bean( name = "second"   CONFIG_STRING )
    protected String second() {
        return CONFIG_STRING;
    }
}