Tomcat Architecture Series-1.Overview & Basic Concepts

//Simplified representation of Tomcat's architecture
Server (Top-level container)
└── Service
    ├── Connector (HTTP/AJP)
    └── Container (Engine)
        └── Host
            └── Context
                └── Wrapper

public interface Server {
    // The main server component
    public Service[] findServices();
    public void addService(Service service);
    public void removeService(Service service);
}

public interface Service {
    // Combines one or more Connectors with a Container
    public Container getContainer();
    public void setContainer(Container container);
    public Connector[] findConnectors();
}

public interface Connector {
    // Handles communication with clients
    public void setPort(int port);
    public void setProtocol(String protocol);
    public Container getContainer();
}

// Simplified request processing flow
public class RequestProcessor {
    public void process(Request request, Response response) {
        // 1. Parse HTTP request
        connector.parse(request);
        
        // 2. Create request/response objects
        Request req = new Request(request);
        Response res = new Response(response);
        
        // 3. Process through container pipeline
        container.getPipeline().invoke(req, res);
        
        // 4. Send response
        response.send();
    }
}

public interface Lifecycle {
    public void init();
    public void start();
    public void stop();
    public void destroy();
}

public interface Pipeline {
    public Valve getBasic();
    public void setBasic(Valve valve);
    public void addValve(Valve valve);
}

<!-- Example server.xml configuration -->
<Server port="8005" shutdown="SHUTDOWN">
    <Service name="Catalina">
        <Connector port="8080" protocol="HTTP/1.1"/>
        <Engine name="Catalina" defaultHost="localhost">
            <Host name="localhost" appBase="webapps"/>
        </Engine>
    </Service>
</Server>