Is it possible to inject Static Enumerated Properties?

[arlevitt]

I am currently injecting properties into a "Car" object. My question below specifically refers to a static enumerated "Direction" type that I also describe below. Here is a simplified version of the Car:

public class Car
{
  public Direction direction;
  public int speed;
  ...
}

My "Direction" class is a static enumeration. Thus, its enumerated types would be accessed in the following manner:

Car car = new Car(Direction.EAST, 55);

The code for the direction class looks like this:

public class Direction
{
    private final String direction;
    
    public static Direction NORTH = new Direction("North");
    public static Direction SOUTH = new Direction("South");
    public static Direction EAST = new Direction("East");
    public static Direction WEST = new Direction("West");
    
    // notice the PRIVATE constructor   
    private Direction(String direction)
    {
        this.direction = direction;
    }
    
    public String toString()
    {
        return this.direction;
    }
}

Refer here for a complete pattern description from Effective Java.

My Spring Xml file is the typical Spring.xml:

<beans>
  ...
  <bean id="car1" class="edu.psu.sweng.model.Car">     
    <constructor-arg index="0">
      <ref bean="east"/>
    </constructor-arg>
    <constructor-arg index="1>
      <value>70</value>
    </constructor-arg>
  </bean>
         
  <!-- Direction Enumerations -->
  <bean id="east" class="edu.psu.sweng.model.Direction" singleton="false">
    <constructor-arg>
      <value>East</value>
    </constructor-arg>
  </bean>
   ...
</beans>

When I refer to the "east" bean, it creates a Direction class, but it is not created properly as one of the enumerated types. I believe this may be a legal operation because Spring is using reflection. I have tried this with and without using [singleton="false"] on the "east" bean. However, I am wondering if anyone knows how to access and inject one of the static types that i have defined. (ie: Direction.EAST instead of just "East")
Any help would be appreciated.

[robh]

It certainly is possible. Take a look at the JavaDoc for FieldRetrievingFactoryBean.

Rob

[arlevitt]

Yes Rob, thank you... here is the answer I came up with, which currently works!
The key here is with the "staticField" property name. The property name MUST be called "staticField".

<bean id="east" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean">
  <property name="staticField">
    <value>edu.psu.sweng.model.Direction.EAST</value>
  </property>
</bean>

[eguy66]

Sweet!
I just joined the forum, because I had exactly the same question. I entered "enumeration" as my search criterion, found this thread, and have my answer. Life is good.
Thanks!
Ed