Goals

• Specify the types of objects to create using the prototype instance and create new objects by copying this prototype.
• Create one instance of the class to use as the source for all future instances.
• The new operator is considered …

Example of "Builder" desnig pattern in Python

"""
Separate the construction of a complex object from its representation so
that the same construction process can create different representations.
"""
 
import abc
 
 
class Director:
    """
    Construct an object using the Builder …

Discussion. The forte of Builder is constructing a complex object step by step. An abstract base class declares the standard construction process, and concrete derived classes define the appropriate implementation for each step of the process. In this example, "distributed …

Example of "Builder" design pattern in Java

/* "Product" */
class Pizza {
    private String dough = "";
    private String sauce = "";
    private String topping = "";
 
    public void setDough(String dough) {
        this.dough = dough;
    }
 
    public void setSauce(String …

This pattern is ideal where you want to isolate your application from the implementation of the concrete classes. For example if you wanted to overlay Delphi's VCL with a common VCL layer for both 16 and 32 bit applications, you …

Goals

Object pooling can greatly improve performance; it is most effective in situations where the cost of initializing an instance of a class is high and the rate of instantiation of the class is high, while the number of instances …

Abstract Factory classes are often implemented with Factory Methods, but they can also be implemented using Prototype. Abstract Factory might store a set of Prototypes from which to clone and return product objects.

• Factory Method: creation through inheritance.
• Prototype: creation …

An example of a design pattern An abstract factory in PHP

<?php
/*
 *  Abstract Factory classes
 */
 
abstract class DB_Abstraction_Factory {
    protected $settings = array();
    protected function __construct() {
        $this->settings = Settings::getInstance();
    }
 
    abstract public function createInstance();
}
 
class …

Goals

• We define an interface for creating an object, but let the subclasses decide which class to create. A factory method allows you to instantiate a class for subclasses.
• Definition of a "virtual" constructor.
• The new operator is harmful.

Problems …

The weekend was not in vain. For a couple of days, I managed to write enough functional support for uploading photos through the WYSIWYG website editor. What I would like to inform the users of the site in the form …