adapter design-pattern2015

Object Oriented Programming

Design Patterns

The Adapter Pattern

An example of Object Oriented PHP

Implementation for

< https://www.drupal.org/project/oop_design_patterns >

OOP Design Patterns

Links

Drupal.org: VicOnt, nafes

Presentation Code:

https://www.drupal.org/project/oop_design_patterns

https://www.drupal.org/project/oop_examples


OOP Design Patterns: The Gang of Four!

It all started around 1994 when a group of 4 IBM programmers:

Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides

based on their coding experience , were able to observe and document

a set of about 23 common problems and their best accepted solutions


OOP Design Patterns

What are design patterns?

Recurring solutions to common software development challenges


O

OOP Design Patterns

Some common software development challenges:

➢ Building new applications while leveraging existing codebases

➢ Building/enhancing applications securely, quickly and effectively

➢ Integrating new and existing applications

➢ Multiple developers programming the same product

➢ Few developers programming many products

➢ Varying, sometimes unknown, data sources, OS, Setups


OOP Design Patterns

What are design patterns not?

a) They are not the end to all of your coding challenges.

b) They are not a requirement of object oriented programming.

c) They are not a substitute for application code and logic.

d) They are not always the best solution for the job.

e) They are not always the easiest concept to grasp and/or use.


b) DDT DRY DOT OnceAndOnlyOnce KISS/YAGNI PARETODon’t Do Twice Don’t Repeat Yourself Do One Thing Each and every declaration of behavior should appear Once (For) You ain't gonna need it 80effort/20functionality

normalization in the RelationalModel and removing redundancies 80%of code is crap

Programmers’ Code, Rule #27, Rules are best broken by those who have mastered them

OOP Design Patterns

GOF Classification for patterns

CreationalWhat: deal with object creation mechanisms

How: somehow controlling the object

creation

Example: Abstract Factory

Create a series of related objects without

specifying their distinct classes.

Usually all classes implements the same

interface.


StructuralWhat: ease/simplify the design

How: by identifying a simple way to realize

relationships between entities.

Example: Adapter/Wrapper

Translate one interface for a class into a

compatible interface –by providing it’s interface

to clients while using the original interface.

BehavioralWhat: identify common communication

patterns between objects

How: realizing these patterns

Example: Template Method

A skeleton of an algorithm, well-suited for

framework libraries. The user implements

one method and the superclass do the job.

OOP Design Patterns

The Adapter Pattern

Purpose: allows the interface of an existing class to be used from another interface. It is often used to make existing classes work with others without modifying their source code.

Examples where Adapter Pattern may help:

• I want to add search capabilities to my application and support

multiple search engines such as Google, Yahoo, Bing…

• Have an image loader for different kinds of images JPG, GIF, PNG…

• Use different Email providers: Gmail, Hotmail, YahooMail…

• Use different data sources: Db, XML, TXT, CSV…

• Connect to different Db: MySQL, PostgreSQL, MSSQL, Oracle

• Have multiple downloads using different protocols: HTTP, HTTPS, FTP…

• Use different payment providers: Moneris, AuthorizeNet, Skrill…


OOP Design Patterns

If Client and Adaptee are incompatible, we may create a new class called Adapter, and place it in between Target and Adaptee.Components become compatible with each other through Adapter.As long as some component integrates incompatible interfaces, it can be considered an adapter.


Usually Adaptee classimplementsthe Target interface.

Client and Adapteeare compatible!

OOP Design Patterns

PHP Adapter: When you've opened a can of worms, then the

only way to seal them again - Is using a bigger jar


The Interface

Incompatible

classes

OOP Design Patterns

Design patterns are a great way to modularize your code

and create reusable structures.

But they mean nothing if they go unused.

Go code something.


OOP Design PatternsThe Problem: multiple Payment Providers


OOP Design PatternsThe Solution: Adapter/Wrapper for Providers 1, 3

< https://www.drupal.org/project/oop_design_patterns >Scope res op

OOP Design PatternsThe Solution: Adapter/Wrapper for Provider 2


OOP Design PatternsAdapter Pattern: UML diagram, programming to the interface


OOP Design PatternsAdapter Pattern: Easy of use, programming to the interface

OOP Design PatternsAdapter Pattern: Drupal 7 implementation


OOP Design PatternsAdapter Pattern: Drupal 8 implementation


OOP Design Patterns

CodeCase in action:


OOP Design Patterns

To be Continued...

Controller (GenRespAsignSoftPatt), Facade (GOF)

➢ Probably one of the most common patterns in OOP

➢ One of the most powerful patterns in development

➢ Opens a wealth of new possibilities, when understood

➢ Very flexible when favoring composition over inheritance

➢ Encapsulates what changes to allow for greater extendability


OOP Design Patterns

Acknowledgments

Donquixote (Andreas Hennings)

For PHP Class loading suite (PSR-4)

https://www.drupal.org/project/xautoload

Nafes (Nik Alexandrov)

For Starting OOP examples in Drupal

https://www.drupal.org/project/oop_examples


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