wro4j-maven-plugin/src/main/java/ro/isdc/wro/maven/plugin/support/ResourceChangeHandler.java
public static ResourceChangeHandler create(final WroManagerFactory managerFactory, final Log log) {
    notNull(managerFactory, "WroManagerFactory was not set");
    notNull(log, "Log was not set");
    return new ResourceChangeHandler().setManagerFactory(managerFactory).setLog(log);
  }
public static ResourceChangeHandler create(final WroManagerFactory managerFactory, final Log log) {
    notNull(managerFactory, "WroManagerFactory was not set");
    notNull(log, "Log was not set");
    return new ResourceChangeHandler().setManagerFactory(managerFactory).setLog(log);
  }
Factory method which requires all mandatory fields.