java 职责链模式（大话设计模式）

职责链模式：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。将这个对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理为止。【组合】

/**
 * 处理请求的接口
 * 
 * @author administrator
 *
 */
public abstract class Handler {

    protected Handler successor;

    public void setSuccessor(Handler successor) {
	this.successor = successor;
    }

    public abstract void handleRequest(int request);
}

// 具体处理者类，处理它所负责的请求，可访问它的后继者，如果可处理该请求，则处理，否则转给它的后继者处理
class ConcreteHandlerA extends Handler {

    @Override
    public void handleRequest(int request) {
	if (request >= 0 && request <= 10) {
	    System.out.println(this.getClass().getName() + "处理了请求" + request);
	} else if (successor != null) {
	    successor.handleRequest(request);
	}
    }

}

class ConcreteHandlerB extends Handler {

    @Override
    public void handleRequest(int request) {
	if (request > 10 && request <= 20) {
	    System.out.println(this.getClass().getName() + "处理了请求" + request);
	} else if (successor != null) {
	    successor.handleRequest(request);
	}
    }

}

class ConcreteHandlerC extends Handler {

    @Override
    public void handleRequest(int request) {
	if (request > 20 && request <= 30) {
	    System.out.println(this.getClass().getName() + "处理了请求" + request);
	} else if (successor != null) {
	    successor.handleRequest(request);
	}
    }

}
/**
 * 向链上的具体处理者对象提交请求
 * 
 * @author administrator
 *
 */
public class Client {
    public static void main(String[] args) {

	Handler handlerA = new ConcreteHandlerA();
	Handler handlerB = new ConcreteHandlerB();
	Handler handlerC = new ConcreteHandlerC();

	handlerA.setSuccessor(handlerB);
	handlerB.setSuccessor(handlerC);

	int[] requests = { 2, 14, 5, 6, 8, 23, 12, 21 };

	for (int i : requests) {
	    handlerA.handleRequest(i);
	}
    }

}

案例 请假

/**
 * 责任链模式(Chain of Responsibility)
 * 抽象管理者
 */
public abstract class Manager {

    protected String name;
    // 管理者的上级
    protected Manager superior;

    public Manager(String name) {
        this.name = name;
    }

    // 设置管理者的上级
    public void setSuperior(Manager superior) {
        this.superior = superior;
    }

    // 申请请求
    public abstract void requestApplications(Request request);

}
/**
 * 责任链模式(Chain of Responsibility)
 * 总监
 */
public class Majordomo extends Manager {

    public Majordomo(String name) {
        super(name);
    }

    @Override
    public void requestApplications(Request request) {
        if (request.getRequestType() == "请假" && request.getNumber() <= 5) {
            System.out.println(name + ": " + request.getRequestContent() + " 数量" + request.getNumber() + " 被批准");
        } else {
            if (superior != null) {
                superior.requestApplications(request);
            }
        }
    }

}
/**
 * 责任链模式(Chain of Responsibility)
 * 总经理
 */
public class GeneralManager extends Manager {

    public GeneralManager(String name) {
        super(name);
    }

    @Override
    public void requestApplications(Request request) {
        if (request.getRequestType() == "请假") {
            System.out.println(name + ": " + request.getRequestContent() + " 数量" + request.getNumber() + " 被批准");
        } else if (request.getRequestType() == "加薪" && request.getNumber() <= 500) {
            System.out.println(name + ": " + request.getRequestContent() + " 数量" + request.getNumber() + " 被批准");
        } else if (request.getRequestType() == "加薪" && request.getNumber() > 500) {
            System.out.println(name + ": " + request.getRequestContent() + " 数量" + request.getNumber() + " 再说吧");
        }
    }

}
/**
 * 责任链模式(Chain of Responsibility)
 * 经理
 */
public class CommonManager extends Manager {

    public CommonManager(String name) {
        super(name);
    }

    @Override
    public void requestApplications(Request request) {
        if (request.getRequestType() == "请假" && request.getNumber() <= 2) {
            System.out.println(name + ": " + request.getRequestContent() + " 数量" + request.getNumber() + " 被批准");
        } else {
            if (superior != null) {
                superior.requestApplications(request);
            }
        }
    }

}
/**
 * 责任链模式(Chain of Responsibility)
 * 申请
 */
public class Request {
    // 申请类别
    private String requestType;
    // 申请内容
    private String requestContent;
    // 数量
    private int number;

    public String getRequestType() {
        return requestType;
    }

    public void setRequestType(String requestType) {
        this.requestType = requestType;
    }

    public String getRequestContent() {
        return requestContent;
    }

    public void setRequestContent(String requestContent) {
        this.requestContent = requestContent;
    }

    public int getNumber() {
        return number;
    }

    public void setNumber(int number) {
        this.number = number;
    }

}
/**
 * 责任链模式(Chain of Responsibility)
 * 客户端main方法
 */
public class Client {

    public static void main(String[] args) {
        CommonManager commonManager = new CommonManager("经理");
        Majordomo majordomo = new Majordomo("总监");
        GeneralManager generalManager = new GeneralManager("总经理");
        commonManager.setSuperior(majordomo);
        majordomo.setSuperior(generalManager);

        Request request = new Request();
        request.setRequestType("请假");
        request.setRequestContent("小菜请假");
        request.setNumber(1);
        commonManager.requestApplications(request);

        Request request2 = new Request();
        request2.setRequestType("请假");
        request2.setRequestContent("小菜请假");
        request2.setNumber(4);
        commonManager.requestApplications(request2);

        Request request3 = new Request();
        request3.setRequestType("加薪");
        request3.setRequestContent("小菜请求加薪");
        request3.setNumber(500);
        commonManager.requestApplications(request3);

        Request request4 = new Request();
        request4.setRequestType("加薪");
        request4.setRequestContent("小菜请求加薪");
        request4.setNumber(1000);
        commonManager.requestApplications(request4);
    }

}