Structural design patterns describe how classes can be combined to form larger structures. These larger structures can generally be easier to work with and hide a lot of the complexity of the individual classes. Most of the patterns in the structural pattern category involve connections between objects.
There are seven well-known patterns that are part of the structural design pattern type:
Adapter: This allows classes with incompatible interfaces to work together
Bridge: This is used to separate the abstract elements of a class from the implementation so that the two can vary
Composite: This allows us to treat a group of objects as a single object
Decorator: This lets us add or override behavior in an existing method of an object
Façade: This provides a simplified interface for a larger and more complex body of code
Flyweight: This allows us to reduce the resources needed to create and use a large number of similar objects