Derived classes should perform whatever conversion logic is required on the specified attribute.
For instance if the attribute changed from a float to a double, you would want to read a float from the input stream and write it into the attribute (making it a double).
Exactly what you do in this process will be dictated by the schema changes you've made.
It is expected that you will read all data from the input stream that is associated with the attribute in question, whether it is single or multi-valued. So, obviously, you should be familiar with the serializeValue()/deserializeValue() functions associated with the the DmcType??? data type in question.
For multi-valued attributes, the next piece of data in the input stream will be the number of values that need to be deserialized. Have a look at DmcAttribute.deserializeIt() to see how this is done.
@param dis the input stream.
@param attr the attribute container that was constructed at the current versionof the schema.