责任链模式
1.责任链模式简介
责任链模式(Chain of Responsibility Pattern)为请求创建了一个接收者对象的链。这种模式给予请求的类型,对请求的发送者和接收者
进行解耦。属于行为型模式。
在这种模式中,通常每个接收者都包含对另一个接收者的引用,构成一个单向链表。如果一个对象不能处理该请求,那么它会把相同的请求传
给下一个接收者,依此类推。
可以避免请求发送者与接收者耦合在一起,客户只需要将请求发送到职责链上即可,无须关心请求的处理细节和请求的传递。让多个对象都有
可能接收请求,将这些对象连接成一条链,并且沿着这条链传递请求,直到有对象处理它为止。
2.试验Demo
abstract class Logger { public static int DEBUG = 1; public static int INFO = 2; public static int ERROR = 3; protected int level; protected Logger nextLogger; public Logger(int level) { this.level = level; } public void setNext(Logger nextLogger) { this.nextLogger = nextLogger; } public void print(int level, String message) { if (level <= this.level) { write(message); } else { if (nextLogger != null) { nextLogger.print(level, message); } } } abstract public void write(String message); } class DebugLogger extends Logger { public DebugLogger(int level) { super(level); } public void write(String message) { System.out.println("DebugLogger: " + message); } } class InfoLogger extends Logger { public InfoLogger(int level) { super(level); } public void write(String message) { System.out.println("InfoLogger: " + message); } } class ErrorLogger extends Logger { public ErrorLogger(int level) { super(level); } public void write(String message) { System.out.println("ErrorLogger: " + message); } } public class ChainPatternDemo { public static void main(String args[]) { Logger logger = createLoggerChain(); logger.print(Logger.DEBUG, "This is a debug message"); logger.print(Logger.INFO, "This is a info message"); logger.print(Logger.ERROR, "This is a error message"); } public static Logger createLoggerChain() { Logger debug = new DebugLogger(Logger.DEBUG); Logger info = new InfoLogger(Logger.INFO); Logger error = new ErrorLogger(Logger.ERROR); debug.setNext(info); info.setNext(error); return debug; } }
参考:https://i.cnblogs.com/EditPosts.aspx?opt=1
posted on 2019-04-16 22:58 Hello-World3 阅读(123) 评论(0) 编辑 收藏 举报