Once the solution structure is defined, every component can be designed in detail. The detailed design is mostly influenced by the functional requirements of the system and the relationship between the components which form the system. Tools such as UML can be used to identify the component relationships. This is where design patterns can be leveraged to improve the quality of the system. Design patterns are categorized into three types – structural, behavioral, and creational. Structural patterns are used to define the composition of objects and behavioral patterns are used to define the communications and algorithms within and across objects. Creational patterns are concerned with the instantiation of objects.