Transcript Component Technology

Component Technology
•
•
•
•
•
objects versus components -- definitions
interoperability
requirements for distribution
a simple workgroup application
extending hush with CORBA
Additional keywords and phrases:
(D)COM, Java, CORBA, OLE, persistent objects, ODMG,
workgroup
Postacademische Cursus Informatie Technologie
vrije Universiteit
amsterdam
Objects versus components
Subsections:
Definitions
The technology matrix
Component myths
Postacademische Cursus Informatie Technologie
vrije Universiteit
amsterdam
Definitions
Component
substitutability
unit of independent deployment
unit of third party composition
no persistent state
Object
identity
unit of instantiation
(persistent) state
encapsulation of state and behavior
Postacademische Cursus Informatie Technologie
vrije Universiteit
amsterdam
A software component is a unit of
composition with contractually
specified interfaces and explicit
context dependencies only. A
software component can be
deployed independently and is
subject to composition by third
parties.
Szyperski
Postacademische Cursus Informatie Technologie
vrije Universiteit
amsterdam
The technology matrix
distribution mobility language platform reflection
COM
*
+/DCOM
+
*
+/+/CORBA
+
*
*
+/Java/Beans
classes
Java
*
+
Java/RMI
+
classes
Java
*
+
Voyager
+
objects
Java
*
+
Postacademische Cursus Informatie Technologie
vrije Universiteit
amsterdam
Components:
Myths
and
Reality
component-ware allows for combining components
if semantical issues can be resolved
component-ware simplifies software distribution and maintenance
development becomes more complex
component-ware support mega applications
it affects performance significantly
component-ware is a revolution
wrong, it is an evolution from OO and C/S
Postacademische Cursus Informatie Technologie
unknown source
vrije Universiteit
amsterdam
Component Questions
• How to describe the interaction between components?
• How to manage variety and flexibility?
• How to guarantee critical system-wide properties?
Postacademische Cursus Informatie Technologie
vrije Universiteit
amsterdam