Proxy Pattern

Purpose

• Allows for object level access contro lby acting as a pass through entity or a placeholder object.

 

Use when

• Access contorl for the original object is required.
• Added functionality is required when an object is accessed.

 

Proxy Pattern

• Proxy pattern provides a surrogate or placeholder for another object to contorl access to it.

 

 

The Roles of Helper Objects

• Request From Client to Server
  - Client Side : The client calls a method on the client helper, as if the cleint helper were the actual service. Then the client helper takes care of forwarding that request to the server.
  - Server Side : The service helper receives the request from the client helper, via a Socket connection, unpacks the information about the call and then invokes the real method on the real service object.
• Reply From Server to Client
  - Server Side : The service helper gets the return value from the service, packs it, and ships it back to the client helper.
  - Client Side : The client helper unpacks the information and returns the value to the client object.

 

Serialization basics

• Serialization
  - the process of transforming an in-memory object to a byte stream.
• Deserialization
  - the inverse process of reconstructiong an object from a byte stream to the same state in which the object was previously serialized.
• An empty interface is called a marker interface.