How to reference a constant in Spring Expression Language

Question

i am quite new to Spring and i have a bean declaration as follows.

    <bean id="mybean" class="" scope="prototype">
       <property name='typeOf' value='#{typeOfBuilder.getKeyFor("OPEN_DATE").getId()}'/>    
</bean> 

typeOf is a type of Integer which is the key of another table which typeOfBuilder builds by Key which is OPEN_DATE in this case.

this code works OK but have a limitation. OPEN_DATE is a constant in a NON-MANAGE Spring Bean something like follows.

public final class Constants
{
     public final static String KEY_FOR_OPEN_DATE = "OPEN_DATE";     
} 

and is strongly recommend to be able to reference to it!!.

something like this.

<util:constant id="PATH_TO_CONSTANT" static-field="myPath"/>
<property name='typeOf' value='#{typeOfBuilder.getKeyFor(PATH_TO_CONSTANT).getId()}'/>  

any help is hugely appreciate.

Solution

The special 'T' operator can be used to specify an instance of java.lang.Class (the 'type'). Static methods are invoked using this operator as well.

Try the code below.

<property name='typeOf' value='#{typeOfBuilder.getKeyFor(T(some.package.Constants).KEY_FOR_OPEN_DATE).getId()}'/>