Visitor

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(Description)
(Description)
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==Description==
 
==Description==
  
The Visitor describes three major roles:
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The Visitor describes three distinct components:
 
*Object Structure: Provides a visitor with access to its elements
 
*Object Structure: Provides a visitor with access to its elements
 
*Element: Accepts visits
 
*Element: Accepts visits
 
*Visitor: Accesses an element to perform operations
 
*Visitor: Accesses an element to perform operations
 
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Figure 1 graphically describes these Visitor pattern interactions.
[[image:Visitor.JPG|frame|centre|A UML class diagram representing the Visitor structure]]
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[[image:Visitor.JPG|frame|centre|'''Figure 1: A UML class diagram representing the Visitor structure''']]

Revision as of 12:21, 30 July 2008

Introduction

The Visitor is a behavioural pattern. It allows the designer to define new operations on an object structure and its elements, without modifying the object structure itself.

Description

The Visitor describes three distinct components:

  • Object Structure: Provides a visitor with access to its elements
  • Element: Accepts visits
  • Visitor: Accesses an element to perform operations

Figure 1 graphically describes these Visitor pattern interactions.

Figure 1: A UML class diagram representing the Visitor structure
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