Software Architecture S09

8/7/2019 Software Architecture S09

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Three-tier Architecture

Manuel Corona

David Nevarez


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Three-tier Architecture


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Comparison to MVC (Model View Control)

Not a triangle, but linear.

Uses

Web applications.

Advantages Modular

Interdependent of other components (reduce

coupling)

Has great control of permissions.


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Interpreter

Software Architecture

Vladimir Soto

Veronica Valenzuela


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What is it?

Given a language, define a representation for

its grammar along with an interpreter that

uses the representation to interpret sentences

in the language.

Map a domain to a language, the language to

a grammar, and the grammar to a hierarchical

object-oriented design.


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What does it solve?

A class of problems occurs repeatedly in a

well-defined and well-understood domain. If

the domain were characterized with a

"language", then problems could be easily

solved with an interpretation "engine".


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Example


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Conclusion

This pattern can be applied for parsing lightexpressions defined in simple grammars andsometimes in simple rule engines.

The Interpreter pattern has a limited area where itcan be applied.

We can discuss the Interpreter pattern only in termsof formal grammars but in this area there are better

solutions and this is the reason why this pattern isnot so frequently used.


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References

http://www.vincehuston.org/dp/interpreter.ht

ml

http://sourcemaking.com/design_patterns/interpreter

http://www.oodesign.com/interpreter-

pattern.html


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By Rick Lawler & Ray Diaz

Client-Server Model


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What is a client?

Any computer or program that makes a

request to a server


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What is the client server model?

Client Server model is

the relationship

between the client and

the server.


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Examples of client-server

Online Gaming

Surfing the internet


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Online gaming

Game console (client)

Central Server


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Internet browsing

Machine /browser (client)

Machine hosting the site (server)


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Distributed Architecture

Ortiz

Montgomery


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Distributed programming typically falls into one ofseveral basic architectures or categories:

DISTRIBUTED COMPUTING

- Client-server

- 3-tier architecture

- N-tier architecture

- Tight coupling


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- Client-server

Contacts the server for data, then formats and displays it to the user.Input at the client is committed back to the server when it represents a

permanent change.



- Tight coupling


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- Client-server

- 3-tier architecture Move the client intelligence to a middle tier so that stateless clients

can be used.


- Tight coupling


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- Client-server



Web applications which further forward their requests to other

enterprise services

-Tight coupling


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- Client-server



- Tight Coupling

A cluster of machines that closely work together, running a shared

process in parallel.


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Batch-Sequential Software

Architecture

David Mireles

Kris Villanueva


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Used for offline processing.

Data is (usually) held in files.

It is processed in a strict sequence by a small number of

standalone systems. Each system transforms the data and writes to a new file

before the next system processes it.

Processed

Data

Validated

Input

Input

Validate

Batch-Sequential Processing

Process Report

Validated

Input

Processed

Data Report


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Batch Sequential Architectures

Are a sub-set of Data Flow Architectures

Pipes and filters executes in parallel

Batch sequential does not

Examples:

Legacy mainframe systems

Compilers

Compression


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When to use BS Architecture

All data is already given.

Processes can be completely modularized.

There are no backward dependenciesbetween processes.

Pipelining the main processes is unnecessary,

impossible, or undesireable.


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Blackboard

David Gomez-Leon

Oscar A. Olivas


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Blackboard

This architecture is composed of knowledge

sources (KSs) and a single blackboard

KSs are programs that create, modify, or remove

messages from the blackboard.

The blackboard is a single repository of messages

and is the only mean of communication between

KSs. In general, a message may represent any form

of input/output between the KSs.


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Blackboard

Pros

KSs are completely independent from each other

and thus are easy to maintain.

The most optimal KS can be selected for any

specific message.

Cons

Complexity involved with communication withinthe blackboard

Complexity involved with which KS to select.


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Data as -c tric is a arc it ct r i

ic ata as s lay a cr cial r l


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Could be a combination of:

Use relational DBM system

Using dynamic table driven logic Using stored procedures that run on database

servers

using a shared database as the basis forcommunicating between parallel processes in

distributed computing applications


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Distribution: Database & UI Portions

Protocol needed

All interaction is accomplished through

database views or APIs.

Nearly all application behavior (including

screen navigation) is handled in the database.


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P2P

Saucedo


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Equal nodes that act as clients and servers at

the same time.

Sometimes there can exist a central server

which assists in the communication between

peers.

P2P uses connectivity to between many

computers in a network and the collective

bandwidth of all partakers rather than a

central resource such as a server.

An important goal in P2P networks is that all

clients provide resources, including

bandwidth, storage space, and computing

power.

Many P2P systems use stronger peers (super-peers, super-nodes) as servers and client-

peers are connected in a star-like fashion to a

single super-peer.


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Valeria Fierro

Neith Estrada


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This architecture is composed of two basic entitiesthe plug-in host and the plug-in itself.

The host could be an application, operating system,or even another plug-in. The plug-in hosts code is

structured such that certain well-defined areas offunctionality can be provided by an external moduleof code.

Plug-ins are written and compiled entirely separately

from the host, typically by another developer. Whenthe host code is executed, it uses whatevermechanism is provided by the plug-in architecture tolocate compatible plug-ins and load them, thusadding capabilities to the host that were not

previously available.


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Useful when you are designing extensible

software.

For ex

ample, Notepad++ has a plug-inarchitecture where you place a .dll file in the

plugins folder, and it adds functionality to the

application that wasn't there, such as color-

picking, or snippet insertion, or many otherthings (a wide range of functionality).

Eclipse Plug-in Architecture


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Search-Oriented

Rodrigo Nuez; Brenda Medina


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Search Oriented Software Architecture

Search engine is the main integration

component of the architectural layer

As opposed to the traditional relational database

management system

Keyboard search instead of SQL queries


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Benefit: rapid response time and more

convenient, in terms as SQL versus keyboard

search

Drawback: The data tier is not as organized

Search Oriented Software Architecture


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Service Oriented

Carmen Avila

Leonel Villagomez

Cesar Yeep


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Group of services that communicate with

each other.


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Is a design for linking computational resources

(principally applications and data) on demand

to achieve the desired results for service

consumers (either end users or other

services).


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The process of communication involves either

simple data-passing or two or more services

coordinating some activity.

Intercommunication implies the need for

some means of connecting two or more

services to each other.


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Aservice:

Is a logical representation of a repeatable

business activity that has a specifiedoutcome (e.g., provide weather data)

Is self-contained

May be composed of other services

Is a black box to consumers of the

service

SOA is an architectural style that supports

service orientation.

Service orientation is a way of thinking in

terms of services and service-based

development and the outcomes of

services.


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To associates individual SOA objectsorchestration is used.

Orchestration is the ability to control howinformation flows and services (behaviors)

interact to form solutions.


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SOA promotes the goal of separating users

(consumers) from the service

implementations. Services can therefore be

run on various distributed platforms and be

accessed across networks. This can also

maximize reuse of services


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Reusable Use of Service, not reuse by copying of code/implementation.

Abstracted Service is abstracted from the implementation.

PublishedPrecise, published specification functionality of service interface, not

implementation.

FormalFormal contract between endpoints places obligations on provider and

consumer.

RelevantFunctionality presented at a granularity recognized by the user as a

meaningful service.


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Shared Nothing

Joshua Martinez

Antonio Garza


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Shared Nothing Architecture

Info from:

Wikipedia.org

The Case for Shared Nothing by Michael Stonebraker

University of California


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Shared Nothing

What:

is a distributed computing architecture in which

each node is independent and self-sufficient, and

there is no single point of contention across thesystem.

Useful?

Mostly used in web development because of itsscalability, system can keep growing just by adding

nodes.


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Shared Nothing

Additional Properties

Each node has its own private memory, disks and

input/output devices.

A SN system may assign applications and partition

data among nodes, with each node having

responsibility for a particular task.

Drawback Maintenance and tuning becomes really hard.


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Shared Nothing

Examples:

Processors not sharing neither peripherals nor

memory.

hierarchical systems

GRID systems.


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Space Based Architecture

Applications consist of self-sufficientprocessing-units.


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Space Based Architecture

Documents

Software Architecture S09