Implementation of the adapter design pattern in the Spring Framework

Spring Framework uses the adapter design pattern to implement a lot of functionality across the framework transparently. The following are some listed classes based on the adapter design pattern in the Spring Framework:

• JpaVendorAdapter
• HibernateJpaVendorAdapter
• HandlerInterceptorAdapter
• MessageListenerAdapter
• SpringContextResourceAdapter
• ClassPreProcessorAgentAdapter
• RequestMappingHandlerAdapter
• AnnotationMethodHandlerAdapter
• WebMvcConfigurerAdapter

The UML diagram for the adapter pattern

Let's understand the preceding UML diagram that illustrates the components of the adapter design pattern:

• The Target Interface: This is the desired interface class that will be used by the clients
• The Adapter class: This class is a wrapper class that implements the desired target interface and modifies the specific request available from the Adaptee class
• The Adaptee class: This is the class that is used by the Adapter class to reuse the existing functionalities and modify them for desired use
• Client: This class will interact with the Adapter class

Let's look at the following sample implementation of the adapter design pattern.