public SPFPerson lookup(String identifier) {
		boolean isReachable = mSearchInterface.lookup(identifier);
		if (isReachable) {
			return new SPFPerson(identifier);
		} else {
			return null;
		}
	}
public SPFPerson lookup(String identifier) {
		boolean isReachable = mSearchInterface.lookup(identifier);
		if (isReachable) {
			return new SPFPerson(identifier);
		} else {
			return null;
		}
	}
public SPFPerson lookup ( String identifier ) { boolean isReachable = mSearchInterface . lookup ( identifier ) ; if ( isReachable ) { return new SPFPerson ( identifier ) ; } else { return null ; } }
Allows to retrieve a reference to a remote person given its identifier.
This reference is valid until the given person is reachable from the
proximity middleware.

@param identifier
@return
Allows to retrieve a reference to a remote person given its identifier . This reference is valid until the given person is reachable from the proximity middleware .