I am a longtime C++ programmer and I'm trying to understand how I would
phrase a common idiom in Java.  Consider the following program in C++,
which reads tokens either from an istringstream (in memory) or from cin
(the console input):

#include <string>
#include <sstream>
#include <iostream>

using namespace std;

void readTokensFromStream(istream &in) {

 string s;

 while(in >> s) {
   cout << "read from token: '" << s << "'" << endl;
 }
}

int main() {

 istringstream fromMem("a man a plan a canal panama");

 readTokensFromStream(fromMem);

 readTokensFromStream(cin);

 return 0;
}

I'd like to be able to write something similar in Java, but it doesn't
appear so easy there.  Whereas in C++, both istringstream and cin are
istreams, in Java you have StringReader (a reader, not a stream) and
System.in (an InputStream, not a reader).  Is there a way to find a
common interface or adapter between the stream and reader/writer worlds
so that the program above can be elegantly stated in Java?  My
definition of elegant would involve abstracting out the difference so
that readTokensFromStream could continue to be a single non-overloaded
method.

Thanks in advance.
Jordan