What are the 5 types of middleware?
- Transaction-oriented
- Procedure-oriented
- Object-oriented
- Message-oriented
- Service-oriented
What are the advantages of Transaction-Oriented middleware?
- Provides ACID properties across distributed database
- Perform transaction across distributed machines
What are the disadvantages of Transaction-Oriented middleware?
- Doesn’t scale
- Components are large-grained
What are the advantages of Procedure-Oriented middleware?
- Make remote call (abstraction)
- Encourages distribution
What are the disadvantages of Procedure-Oriented middleware?
- Tight binding
- Can’t reliably detect failure
- Language dependent
What are the advantages of Object-Oriented middleware?
- Encapsulated state
- Strong interfaces which define ways to access the objects
- No explicit de-allocation
What are the disadvantages of Object-Oriented middleware?
- Challenging to develop IDL
- Need to find a uniform way to interact with object references
What are the advantages of Message-Oriented middleware?
- Location transparent
- Provides an abstraction for routing
- Asynchronous
- Dynamically add new components (more specialised)
- Define QoS guarantees
What are the disadvantages of Message-Oriented middleware?
- Sender doesn’t know if their message has been received
- Can only be tackled at a system level
- Potentially more complex function in the server
What are the advantages of Service-Oriented middleware?
- No notion of state
- Services are accessed using endpoints
What are the disadvantages of Service-Oriented middleware?
- Heavy messages because state is in messages
- Less intuitive
- Doesn’t map to every application
