chery

• Inheritance


  Use the keyword EXTEND to inherit other class, it is basically inheriting a class to another class
• Parent Class


  Also called Super class or base class
• Child Class


  Also called derived class or sub class
• Interface


  Blueprint of a class, We use IMPLEMENT keywords to implement an interface in class. If the class implements the interface the class now called a CONCRETE CLASS. Also only public method are used in interface, and only handle methods with no attributes.
• Design Pattern


  Solution to software design and also known as pre-made blueprints
• Pattern


  High level solution where we don't have a exact sequence of actions to achieve a goal
• Algorithm


  Need to follow step procedures to achieve a goal
• The invention of Design Patterns

  First described by Christopher Alexander in Pattern Language: Towns, Buildings, Construction. In 1994, Erich Gamma, John Visslides, Ralph Johnson, and Richard Helm got the idea from Christopher to apply the patterns in programming. They published a book "Design Patterns: Elements of Reusable Object-Oriented Software" which had 23 features.
• The Gang of Four (GoF) book


  The book by Erich Gamma, John Visslides, Ralph Johnson, and Richard Helm on Design Patterns
• Why we need to learn Design Patterns


  • It is a toolkit of tried and tested solution in software design. It teaches you to solve problems using object oriented design. It enables better communication with developers.
• Criticism of Design Patterns

  • Kludges for weak programming languages
  • Inefficient solutions
  • Unjustified used
• Idioms


  The most basic and low level design patterns
• Architectural Patterns


  The high level design patterns
• 3 Categories of Design Patterns

  • Structural Patterns
  • Creational Patterns
  • Behavioral Patterns
• Facade Pattern


  A structural design pattern that provides a simplified interface to a number of complex sets of subsystems. The facade is a wrapper that hides the interactions between these subsystems and makes it easy to use. The objective is to simplify the process or the function calls.
• Decorator Pattern


  A structural design pattern that attaches additional responsibilities to a class dynamically using wrapper objects called decorators. The objective is to extend an object's behaviour dynamically using composition.
• Factory Method Pattern


  A creational design pattern that creates a method in superclass and instantiates in subclass. The objective is to encapsulate the object logic to separate it from business logic.
• Singleton Pattern

  A creational design pattern that ensures only one instance of an object exists and is accessible globally. The objective is to have more control over a global object.
• Observer Pattern


  A behavioral design pattern that defines a one-to-many relationship between objects such that when the state of an object (publisher) changes, the other objects (subscribers) are notified.
• Chain of Responsibility Pattern

  A behavioral design pattern that allows you to create a chain of objects, where each object in the chain has the ability to either handle a request or pass it on to the next object in the chain.
• Scripting Languages


  Primarily used to build and automate tasks for websites and web applications while using an existing program. Useful for extracting information from a dataset.
• Server-side Scripting


  Occurs on the back-end. Used to create dynamic pages and can access the file system residing at the webserver. A server-side environment that runs on a scripting language is a web server.
• Client-side Scripting


  Executed on web browsers. Used to create visually appealing websites for users.
• All scripting languages are programming languages, but not all programming languages are scripting languages.
• Scripting Techniques


  • Text Processing
  • Automation
  • Modularity
  • Error Handling
  • Interfacing with APIs
  • Shell Scripting
  • Documentation and Comments
  • Version Control
  • Testing and Debugging
  • Optimization
• Role of Scripting Languages

  • Automation
  • Rapid Prototyping
  • Glue Language
  • Web Development
  • Customization and Extension