Decorator design pattern
The decorator design pattern is a structural pattern that dynamically adds responsibilities or behavior to an object by wrapping it with objects that preserve its interface.
Software Design for Python Programmers
The Decorator Design Pattern is a structural design pattern that dynamically attaches additional responsibilities to an object by wrapping it with objects that share its interface.
- How it is used
- Models runtime extension of object responsibilities when inheritance or aggregation would hardcode the available variations.
- How deep it goes
- Explains the pattern through a flawed ticket design, wrapper classes, recursive cost delegation, and a generic role mapping.
- Examples
- Uses base tickets, pregame parties, VIP seating, and repeated drink coupons to demonstrate inflexible attributes and flexible wrapper chains.
- What you can do after
- Build it from scratch by defining a shared component, a wrapper holding that component, and decorators that extend delegated behavior.
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Object-Oriented Software Design in C++
A structural design pattern that attaches additional responsibilities to an object dynamically through wrapper objects that preserve the wrapped object's interface.
- How it is used
- Uses wrapper objects to add ticket attributes and behaviors dynamically while keeping decorated and undecorated tickets interchangeable.
- How deep it goes
- Explains the problem, refactoring, inheritance structure, nested delegation, and C++ implementation, but does not discuss broader trade-offs.
- Examples
- Demonstrates base tickets decorated with party access, VIP seating, and repeated drink coupons.
- What you can do after
- Builds a C++ decorator chain that calculates combined responsibilities through a shared Ticket interface.
Read how Object-Oriented Software Design in C++ explains decorator design pattern →
Related concepts
- design patternkind of · A design pattern is a reusable, general solution structure for a recurring software design problem in a particular context.
- inheritancealternative to · Inheritance is a mechanism by which a child type or element receives properties, values, or behavior from a parent, subject to system rules and possible overrides.
- hardcodingaddresses · Hardcoding is embedding fixed values, rules, configuration, or behavioral choices directly in a program or its implementation rather than supplying or deriving them separately.
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