31) intercepting filter design pattern

类别：

 

问题：

 

方案：

 

 

 

示例：

 

import java.util.ArrayList;
import java.util.List;

public class InterceptingFilterPatternDemo {
    public static void main(String[] args) {
        FilterManager filterManager = new FilterManager(new Target());
        filterManager.setFilter(new AuthenticationFilter());
        filterManager.setFilter(new DebugFilter());
        Client client = new Client();
        client.setFilterManager(filterManager);
        client.sendRequest("home");
    }
}

interface Filter {
    public void execute(String request);
}

class AuthenticationFilter implements Filter {
    public void execute(String request) {
        System.out.println("filter Authenticating : " + request);
    }
}

class DebugFilter implements Filter {
    public void execute(String request) {
        System.out.println("filter Log: " + request);
    }
}

class Target {
    public void execute(String request) {
        System.out.println("target Executing : " + request);
    }
}

class FilterChain {
    private List<Filter> filters = new ArrayList<Filter>();
    private Target target;

    public void addFilter(Filter filter) {
        filters.add(filter);
    }

    public void execute(String request) {
        for (Filter filter : filters) {
            filter.execute(request);
        }
        target.execute(request);
    }

    public void setTarget(Target target) {
        this.target = target;
    }
}

class FilterManager {
    FilterChain filterChain;

    public FilterManager(Target target) {
        filterChain = new FilterChain();
        filterChain.setTarget(target);
    }

    public void setFilter(Filter filter) {
        filterChain.addFilter(filter);
    }

    public void filterRequest(String request) {
        filterChain.execute(request);
    }
}

class Client {
    FilterManager filterManager;

    public void setFilterManager(FilterManager filterManager) {
        this.filterManager = filterManager;
    }

    public void sendRequest(String request) {
        filterManager.filterRequest(request);
    }
}

 

filter Authenticating : home
filter Log: home
target Executing : home

 

应用：

 

不足：(

 

优化：）