SOA - How to define constant in SOA application?

In any project, we always have some constants needed to be defined. In Java, we can define them as constant by the follow keywords.
public static final


How could we define constant in SOA project to eliminate hard-coded text?
So far, in the SOA env, the only common place to put common value is the MDS. The DVM looks like the correct choice.

In the transformation, we can use DVM to get a constant value base on the name. Like in the follow condition, the DVM value will be used as an input parameter of the condition.

As the key is predefined, we don't need to change it when we change the DVM value. This will eliminate the hard-coded text in a transformation or assign.

All the data defined in DVM can be modified by SOA Composer after the application deployed. The composer URL is http://hostname:port/soa/composer or you can access composer from composer link in EM, which can be found in Applications Deployment.

The cross referencing feature enables you to dynamically integrate values between applications, whereas domain value maps enable you to specify values at design time and edit values at runtime. (Reference: 46 Working with Cross References of Developer's Guide for Oracle SOA Suite)