The Adapter pattern is a structural design pattern that allows the interface of a class to be converted into another interface expected by the client. Python provides a flexible way to implement the Adapter pattern. The following is a complete example code of using Python to implement the Adapter pattern: ```python #Target interface class Target: def request(self): pass #Classes that need to be adapted class Adaptee: def specific_request(self): print("Adaptee specific_request") #Adapter Class class Adapter(Target): def __init__(self, adaptee): self.adaptee = adaptee def request(self): self.adaptee.specific_request() #Client code def client_code(target): target.request() #Creating Adapt Objects adaptee = Adaptee() adapter = Adapter(adaptee) #Client directly uses adapter client_code(adapter) ``` In the above code, we defined the Target interface and implemented the Adaptee class, which contains the specific requests we need to adapt to (specific_request). Then, we created an adapter class Adapter, which inherits from the Target interface and takes the Adaptee object as a parameter in the constructor. Finally, in the client code, we instantiated the Adaptee object and the Adapter object, and used the Adapter object to call the request() method to adapt to specific requests of the Adaptee class. Running the above code will output "Adaptee specific_request", which indicates that the Adapter pattern successfully adapts the interface of the Adaptee class to the Target interface.

The Adapter pattern HandlerAdapter in the Spring framework is used to adapt different types of processors (Handlers) and the calling methods of DispatcherServlet. According to different processor types, Spring will use different HandlerAdapters to adapt the calling method of the processor to the calling method of the DispatcherServlet. HandlerAdapter is an interface that defines the methods of a processor adapter, including determining whether the processor supports it, executing the processor, and so on. There are multiple different types of HandlerAdapter implementation classes in the Spring framework, including SimpleControllerHandlerAdapter, HttpRequestHandlerAdapter, HandlerExceptionResolverAdapter, and so on. The following is the complete source code of the HandlerAdapter interface in the Spring framework: ```java public interface HandlerAdapter { boolean supports(Object handler); @Nullable ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception; long getLastModified(HttpServletRequest request, Object handler); } ``` The core idea of the Adapter pattern is to unify different types of processors into a standard calling method through the adapter, so that the caller does not need to care about the specific type of processor, and directly uses the adapter to call. In the Spring framework, the HandlerAdapter plays this role by adapting different types of processors to the calling methods of DispatcherServlet, enabling unified processing of different types of processors in DispatcherServlet. Summary: 1. HandlerAdapter is one of the applications of the Adapter pattern in the Spring framework, which is used to adapt different types of processors to the calling method of DispatcherServlet. There are multiple different types of HandlerAdapter implementation classes in the Spring framework, each of which is adapted to a specific type of processor. The HandlerAdapter interface defines the methods that the adapter must implement, including determining whether it supports processors, executing processors, and so on. 4. The core idea of the Adapter pattern is to unify objects of different types into a standard invocation method through the adapter, so that the caller does not need to care about the specific types of objects. In the Spring framework, HandlerAdapters adapt different types of processors to the calling method of DispatcherServlet, enabling unified processing of different types of processors in DispatcherServlet.

In the Android framework, Adapter pattern is a pattern used to bind data sources to UI elements. BaseAdapter is a basic adapter class in the Android framework that provides some basic methods and functions for displaying the content of data sources. The BaseAdapter class is located in the android.widget package and is an abstract class that needs to be inherited to create a custom adapter. Here is the complete source code of the BaseAdapter: ```java public abstract class BaseAdapter { //Returns the total number of data items in the data source public abstract int getCount(); //Returns the data item at the specified location public abstract Object getItem(int position); //Returns the unique identifier of a data item at a specified location public abstract long getItemId(int position); //Returns the view used to display the specified location public abstract View getView(int position, View convertView, ViewGroup parent); //Returns the number of types used to display the view at the specified location public int getViewTypeCount() { return 1; } //Returns the view type where the data item at the specified location is located public int getItemViewType(int position) { return 0; } //Returns whether the view at the specified location is available public boolean isEnabled(int position) { return true; } //Returns the ID of the view, if any public long getItemIdAtPosition(int position) { return getItemId(position); } //Remove the specified data item from the adapter public void remove(Object object) { } } ``` Summary: Adapter pattern is a common design mode in Android development, which is mainly used to bind data sources with UI elements to achieve data display and interaction. BaseAdapter is a basic adapter class in the Android framework that provides some basic methods and functions. By inheriting the BaseAdapter class, we can customize the adapter and implement various methods according to actual needs to meet different business needs. By using BaseAdapter, various complex list and grid layouts can be achieved, and data sources and views can be easily managed, achieving dynamic updates of data and reuse of views. At the same time, BaseAdapter also provides some extension methods, such as removing specified data items, to facilitate operations on the data source. It should be noted that although BaseAdapter provides some basic implementation methods, not all methods need to be implemented in custom adapters, and can be selectively implemented according to actual needs.

In the Spring framework, the Adapter pattern is used to adapt different types of processors to a unified processor interface. Among them, HandlerAdapter is an interface used to define the specifications of processor adapters. The Spring framework provides multiple different types of HandlerAdapters to adapt to different types of processors. The function of a HandlerAdapter is to adapt processors (such as Controller, HttpRequestHandler, etc.) to a unified processor interface, so that different types of processors can be executed by calling unified processing methods through the interface. ```java public interface HandlerAdapter { boolean supports(Object handler); ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception; } ``` There are two methods defined in the HandlerAdapter interface: -Supports (Object handler): Determine whether the adapter supports the given processor type. -Handle (HttpServletRequest request, HttpServletResponse response, Object handler): Process the request and execute the adapted processor. The HandlerAdapter in Spring implements these two methods, which are used to adapt different types of processors to a unified processor interface. Spring provides multiple implementation classes for HandlerAdapters, such as RequestMappingHandlerAdapters, SimpleControllerHandlerAdapters, etc., to adapt to different types of processors. The specific code implementation is as follows: ```java public class SimpleControllerHandlerAdapter implements HandlerAdapter { public boolean supports(Object handler) { return (handler instanceof SimpleController); } public ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { return ((SimpleController) handler).handleRequest(request, response); } } ``` The above code is an implementation of SimpleControllerHandlerAdapter, which is adapted to processors that implement the SimpleController interface. Its supports method determines whether the given processor is of type SimpleController, and the handle method calls the handler's handleRequest method to process the request. Summary: The Adapter pattern is widely used in the Spring framework, especially in the process of processing requests. The HandlerAdapter pattern enables the framework to adapt to different types of processors and handle requests through a unified interface. This can reduce the code complexity of the framework, improve code reusability and flexibility. With the support of HandlerAdapters, the Spring framework can adapt to various types of processors and manage and schedule them uniformly.