Dom Software Architecture Week 8
This week I want to go more in depth on the topics which I discussed in last week’s blog 7. Resource tier, Service tier and connectivity. I will also add one more new topics Client tier.
Resource tier:
Enterprise Information System (EIS) usually holds data that use used by the servicer of the software or application. It is were most data and sensor feeding information is kept.
Databases are typically used to persist data in a centralized repository designed in compliance with a relational model. Other types include hierarchal databases and native XML databases. Each type of database is tasked with handling centralized persistence of data that may be retrieved later for a variety of purposes. Databases vary in size and complexity based on the amount and nature of the data stored, and may be supplemented by classic filesystems or other data-storage mechanisms.
Directories: Lookup mechanisms that persist and maintain records containing information about users. One example is user authentication information or data pertaining to user information.
Service tier
Service invocation layer: This layer is where listeners are implemented to recognized events that trigger services that require an action by the system. I capable of using several different adapters or event listeners to allow invocation of services. Example (SOAP or XML over HTTP)
Service Container: What Service Container does is carry out a service invocation request. This happens until either successfully concluded or until it hits a error.
Client tier
Controller: This is where the master logic that run all aspects of client tier is held. Its where decision wit respect to security and enforcement are made. An example made in the book is if the client is a browser then all media rendering and communication manangement is made by the core browser ligic
Data/state management: This area allows the system to hold on to data used or mutated by the client. This is important for reason like rollback and for auditing purposes. “Companies like Google and Adobe are getting very aggressive in developing advanced functionality with respect to data and state management to allow online and offline experiences to blend (i.e., using Google Gears and the Adobe Integrated Runtime, or AIR). Mozilla’s Firefox browser now supports connections to SQLite databases as well.”
