code: public ScriptEnvironment getEnvironment(String environmentName) {
        Preconditions.checkArgument(StringUtils.isNotNullOrBlank(environmentName),
                                    "Environment name cannot be null or empty"
                                   );
        ScriptEngine engine = engineManager.getEngineByName(environmentName);
        Preconditions.checkArgument(engine != null, environmentName + " is an unknown.");
        environmentName = engine.getFactory().getEngineName();
        if (!environments.containsKey(environmentName)) {
           environments.put(environmentName, new ScriptEnvironment(engine));
        }
        return environments.get(environmentName);
     }
docs: Gets the scripting environment given the environment name.
  
  @param environmentName the scripting environment name
  @return the scripting environment