# Popular Design Patterns

This is an excerpt from Code Complete by Steve McConnell. 

Table 5-1 Popular Design Patterns

*Abstract Factory*
Supports creation of sets of related objects by specifying the kind of set but not the kinds of each specific object.

*Adapter*
Converts the interface of a class to a different interface.

*Bridge*
Builds an interface and an implementation in such a way that either can vary without the other varying.

*Composite*
Consists of an object that contains additional objects of its own type so that client code can interact with the top-level object and not concern itself with all the detailed objects.

*Decorator*
Attaches responsibilities to an object dynamically, without creating specific subclasses for each possible configuration of responsibilities.

*Facade*
Provides a consistent interface to code that wouldn’t otherwise offer a consistent interface.

*Factory Method*
Instantiates classes derived from a specific base class without needing to keep track of the individual derived classes anywhere but the Factory Method.

*Iterator*
A server object that provides access to each element in a set sequentially.

*Observer*
Keeps multiple objects in synch with one another by making an object responsible for notifying the set of related objects about changes to any member of the set.

*Singleton*
Provides global access to a class that has one and only one instance.

*Strategy*
Defines a set of algorithms or behaviors that are dynamically interchangeable with each other.

*Template Method*
Defines the structure of an algorithm but leaves some of the detailed implementation to subclasses.