Building Android Library From Scratch

ExampleClient.java

public class ExampleClient {
  public static final String ENVIRONMENT_DEV = "DEV";
  public static final String ENVIRONMENT_PROD = "PROD";
  public static final String ENVIRONMENT_STAGING = "STG";

  @Retention(RetentionPolicy.SOURCE)
  @StringDef({ENVIRONMENT_DEV, ENVIRONMENT_PROD, ENVIRONMENT_STAGING})
  public @interface Environment {
  }

  private ExampleClient(Context context, String key, int logLevel, @Environment String environment) {

  }


  private static Builder {

    private Context context;
    private String key; 
    private int logLevel;
    private String environment

    public Builder(Context context, String key) {
      this.context = context;
      this.key = key;
    }

    public Builder setLogLevel(int logLevel) {
      this.logLevel = logLevel;
      return this;
    }

    public Builder setEnvironment(@Environment String environment) {
      this.environment = environment;
      return this;
    }

    public ExampleClient build() {
      return new ExampleClient(this.context, this.key, this.logLevel, this.environment)
    }

  }

}