Java设计模式-责任链模式

责任链原理：

责任链模式是指使多个对象都有机会处理请求，从而避免请求的发送者和接收者之间的耦合关系。将这些对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理它为止。

代码实例：

购买请求

package factorymode.simplefactory.chain;
public class PurchaseRequest {
    private int type = 0;
    private int Number = 0;
    private float price = 0;
    private int ID = 0;
    public PurchaseRequest(int type, int number, float price) {
        this.type = type;
        Number = number;
        this.price = price;
//        this.ID = ID;
    }
    public float GetSum() {
        return Number * price;
    }
    public int getType() {
        return type;
    }
    public void setType(int type) {
        this.type = type;
    }
    public int getNumber() {
        return Number;
    }
    public void setNumber(int number) {
        Number = number;
    }
    public float getPrice() {
        return price;
    }
    public void setPrice(float price) {
        this.price = price;
    }
    public int getID() {
        return ID;
    }
    public void setID(int ID) {
        this.ID = ID;
    }
}

处理对象的父类

package factorymode.simplefactory.chain;
public abstract class Approver {
    Approver successor;
    String name;
    public Approver(String name) {
        this.name = name;
    }
    public abstract void ProcesssRequest(PurchaseRequest request);
    public void SetSuccessor(Approver successor) {
        this.successor = successor;
    }
}

组长请求者

package factorymode.simplefactory.chain;
public class GroupApprover extends Approver {
    public GroupApprover(String name) {
        super(name);
    }
    @Override
    public void ProcesssRequest(PurchaseRequest request) {
        if ( request.GetSum() < 5000 ) {
            System.out.println("This request " + request.getID()
                + "will be handled by " + this.name);
        } else {
            successor.ProcesssRequest(request);
        }
    }
}

部长请求者

package factorymode.simplefactory.chain;
public class DepartmentApprover extends Approver {
    public DepartmentApprover(String name) {
        super(name);
    }
    @Override
    public void ProcesssRequest(PurchaseRequest request) {
        if ( ( 5000 <= request.GetSum()) && (request.GetSum() < 10000) ) {
            System.out.println("This request " + request.getID()
                    + "will be handled by " + this.name);
        } else {
            successor.ProcesssRequest(request);
        }
    }
}

发送请求客户端

package factorymode.simplefactory.chain;
public class Client {
    public Client() {
    }
    public PurchaseRequest sendRequest(int type, int Number, float price ) {
        return new PurchaseRequest(type, Number, price);
    }
}

主程序

package factorymode.simplefactory.chain;
public class Main {
    public static void main(String[] args) {
        Client mclient = new Client();
        Approver groupleader = new GroupApprover("Tom");
        Approver departmentleader = new DepartmentApprover("Jerry");
        groupleader.SetSuccessor(departmentleader);
        departmentleader.SetSuccessor(groupleader);
        groupleader.ProcesssRequest(mclient.sendRequest(1,100, 40));
        groupleader.ProcesssRequest(mclient.sendRequest(2,200,40));
    }
}