Spring profiles

As Java projects pass from development into production it is sometimes necessary to use different suites of project dependencies and settings, loaded as a profile. In a typical Spring project this can be achieved following a project structure such as:

A class service.LoaderService

package com.diffblue.service;
import com.diffblue.loader.Loader;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
// Simple service implementation
@Service
public class LoaderService {
  private final Loader loader;
  @Autowired
  public LoaderService(Loader loader) {
    this.loader = loader;
  }
  public String getMessage() {
    return "service + " + loader.getMessage();
  }
}

has an instance of an interface loader.Loader.

package com.diffblue.loader;
// Example interface.
public interface Loader {
  String getMessage();
}

Another class loader.MyLoader implements that interface,

package com.diffblue.loader;
/**
* Simple implementation of a loader.
*/
public class MyLoader implements Loader {
  private final String message;
  public MyLoader(String message) {
    this.message = message;
  }
  public String getMessage() {
    return message;
  }
}

which is used to supply the loader.Loader interface.

This is done in a class config.ProductionConfig where the user has the possibility to configure the loader by using the @Configuration and @Profile() annotations:

package com.diffblue.config;
import com.diffblue.loader.Loader;
import com.diffblue.loader.MyLoader;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Profile;
/**
* Load a "production" loader when we're not
* using the test-scenario profile.
*/
@Configuration
@Profile("!test-scenario")
public class ProductionConfig {
  @Bean
  public Loader getLoader() {
    return new MyLoader("production");
  }
}

The class config.ProductionConfig should be annotated with @Profile("!test-scenario") in production mode:

When using IntelliJ, the Spring profile in use must be declared in Run > Edit Configurations > VM Options:

In development mode, the annotation @Profile("test-scenario"), should be used in a class config.TestConfig placed in the test directory:

package com.diffblue.config;
import com.diffblue.loader.Loader;
import com.diffblue.loader.MyLoader;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Profile;
/**
* Load a "test" loader when we are using the test-scenario profile.
*/
@Configuration
@ComponentScan
@Profile("test-scenario")
public class TestConfig {
  @Bean
  public Loader getLoader() {
    return new MyLoader("test");
  }
}

which configures a test loader through the loader.TestLoader also placed in the test directory

package com.diffblue.loader;
import org.springframework.context.annotation.Profile;
/**
* Simple implementation of a loader.
*/
@Profile("test-scenario")
public class TestLoader implements Loader {
  private final String message = "static-test-loader";
  public String getMessage() {
    return message;
  }
}

These two classes are placed in the test directory in order to be isolated from a run in the production mode.

To use a specific profile in development mode, the --active-profiles option must be used:

dcover create --active-profiles=test-scenario