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责任链模式(chain of responsbility)

责任链模式定义如下:

  avoid coupling the sender of a request to its receiver by giving more than one object a chance to handle the request.Chain the receiving objects and pass the request along the chain until an object handles it.

  (使得多个对象都有机会处理请求,从而避免了请求的发送者和接受者之间的耦合关系。将这些对象连成一条链,并沿着这条链条传递请求,直到有对象处理为止)

应用:

责任链模式的优点:

  责任链模式非常显著的优点是将请求和处理分开。请求者可以不用知道是谁处理的,处理者可以不用直到请求的全貌,两者解耦和,提高系统灵活性。

责任链模式的缺点:

  1、性能问题,每个请求都是从链头遍历到链尾,特别是链比较长的时候,性能问题非常显著。

  2、调试不方便,处理链中或许设计子递归,调试逻辑复杂。

使用意见:

  给链设置一个最大长度,避免出现过长的链,使得性能最佳。

package chainOfResponsibility;

public interface Handle {
    String doHandle(String str);
}
package chainOfResponsibility;

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

public class HandleChain {
    
    private List<Handle> list = new ArrayList<Handle>();
    
    public HandleChain addHandle(Handle e) {
        list.add(e);
        return this;
    }
    public String doHandle(String str){
        String result = str;
        for (Handle handle : list) {
            result = handle.doHandle(result);
        }
        return result;
    }
}
package chainOfResponsibility;

public class LineHandle implements Handle{

    @Override
    public String doHandle(String str) {
        return str.replaceAll("html", "wangye");
    }

}
package chainOfResponsibility;

public class NameHandle implements Handle{

    @Override
    public String doHandle(String str) {
        return str.replace("name", "nyx");
    }

}
package chainOfResponsibility;

public class SexHandle implements Handle{

    @Override
    public String doHandle(String str) {
        return str.replace("1", "男");
    }

}
package test;

import chainOfResponsibility.HandleChain;
import chainOfResponsibility.LineHandle;
import chainOfResponsibility.NameHandle;
import chainOfResponsibility.SexHandle;

public class Main {
    public static void main(String[] args) {
        LineHandle lh = new LineHandle();
        NameHandle nh = new NameHandle();
        SexHandle sh = new SexHandle();
        HandleChain hc = new HandleChain();
        hc.addHandle(lh).addHandle(nh).addHandle(sh);
        String str = "--111---name---html--";
        String res = hc.doHandle(str);
        System.out.println(res);
    }
}

最后结果:

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责任链模式(chain of responsbility)