•3-(or
more)-tier architecture - Web browser
front-ends, legacy (e.g. databases, HPC
modules) backends; fat middleware
•Use as appropriate the alternative / competing Middleware models:
–Java RMI+
EJB (Enterprise Javabean) - single language solution by Sun
–CORBA - all languages solution by OMG
–COM - multi-language solution by Microsoft
–SOAP/XML - emergent solution by the Web Consortium
•Each model has different tradeoffs (most elegant, powerful, fastest, simplest)
•POW attempts to integrate various models and services in terms of multi-protocol
middleware servers
•Note Java
is often the best language to build middleware whether this is Java or some other
distributed object model
–Most commercial
Java activity is on Server not Client