Java设计模式-----Chain of Responsibility职责链模式

 源自：http://www.blogjava.net/flustar/archive/2007/12/14/cor.html

Chain of Responsibility职责链模式：

为了避免请求的发送者和接收者之间的耦合关系，使多个接受对象都有机会处理请求。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。

例子：

public class Boy {private boolean hasCar; // 是否有车private boolean hasHouse; // 是否有房private boolean hasResponsibility; // 是否有责任心public Boy() {}public Boy(boolean hasCar, boolean hasHouse, boolean hasResponsibility) {this.hasCar = hasCar;this.hasHouse = hasHouse;this.hasResponsibility = hasResponsibility;}public boolean isHasCar() {return hasCar;}public void setHasCar(boolean hasCar) {this.hasCar = hasCar;}public boolean isHasHouse() {return hasHouse;}public void setHasHouse(boolean hasHouse) {this.hasHouse = hasHouse;}public boolean isHasResponsibility() {return hasResponsibility;}public void setHasResponsibility(boolean hasResponsibility) {this.hasResponsibility = hasResponsibility;}}public interface Handler { public void handleRequest(Boy boy);}public class HouseHandler implements Handler {private Handler handler;public HouseHandler(Handler handler) {this.handler = handler;}public Handler getHandler() {return handler;}public void setHandler(Handler handler) {this.handler = handler;}public void handleRequest(Boy boy) {if (boy.isHasHouse()) {System.out.println("没想到吧，我还有房子");} else {System.out.println("我也没有房");handler.handleRequest(boy);}}}public class CarHandler implements Handler {private Handler handler;public CarHandler(Handler handler) {this.handler = handler;}public Handler getHandler() {return handler;}public void setHandler(Handler handler) {this.handler = handler;}public void handleRequest(Boy boy) {if (boy.isHasCar()) {System.out.println("呵呵，我有辆车");} else {System.out.println("我没有车");handler.handleRequest(boy);}}}public class ResponsibilityHandler implements Handler {private Handler handler;public ResponsibilityHandler(Handler handler) {this.handler = handler;}public Handler getHandler() {return handler;}public void setHandler(Handler handler) {this.handler = handler;}public void handleRequest(Boy boy) {if (boy.isHasResponsibility()) {System.out.println("我只有一颗带Responsibility的心");} else {System.out.println("更没有责任心");handler.handleRequest(boy);}}}public class Girl {public static void main(String[] args) {Boy boy = new Boy(false, false, true);// 这个boy没有车，也没有房，不过很有责任心Handler handler = new CarHandler(new HouseHandler(new ResponsibilityHandler(null)));// 也可以使用setHanlder方法handler.handleRequest(boy);}}