Java拦截过滤器模式 (Intercepting Filter )实现方法

package com.demo.gof;
public interface Filter {
   public void execute(String request);
}

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

package com.demo.gof;
public class DebugFilter implements Filter {
   public void execute(String request){
      System.out.println("request log: " + request);
   }
}

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

package com.demo.gof;
import java.util.ArrayList;
import java.util.List;
public 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;
   }
}

package com.demo.gof;
public 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);
   }
}

package com.demo.gof;
public class Client {
   FilterManager filterManager;
   public void setFilterManager(FilterManager filterManager){
      this.filterManager = filterManager;
   }
   public void sendRequest(String request){
      filterManager.filterRequest(request);
   }
}

package com.demo.gof;
public class InterceptingFilterDemo {
   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");
   }
}