设计模式java——职责链模式

职责链模式（Chain of Responsibility）：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它为止。

职责链模式Demo：

/**
 * 2018年4月7日下午10:03:29
 */
package com.Designpattern;

/**
 * @author xinwenfeng
 *
 */
public class TestChainOfResponsibility {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		ChainHandler teacher = new teacherHandler();
		ChainHandler director = new directorHandler();
		ChainHandler schoolmaster = new schoolmasterHandler();
		teacher.setNextHandler(director);
		director.setNextHandler(schoolmaster);
		teacher.handle(4);
		teacher.handle(22);
		teacher.handle(55);
		teacher.handle(500);
		System.out.println("=======================");
		//恰好主任不在
		teacher.setNextHandler(schoolmaster);//老师直接找校长
		teacher.handle(4);
		teacher.handle(22);
		teacher.handle(55);
		teacher.handle(500);
	}

}
abstract class ChainHandler{
	protected ChainHandler nextHandler;
	public void setNextHandler(ChainHandler nextHandler) {
		this.nextHandler = nextHandler;
	}
	public abstract void handle(int days);
}
class teacherHandler extends ChainHandler{

	@Override
	public void handle(int days) {
		if(days <= 7) {
			System.out.println("OK，老师批准假期（天）："+days);
		}else {
			System.out.println("老师无法批准 "+days+" 天");
			nextHandler.handle(days);
		}
	}
	
}
class directorHandler extends ChainHandler{

	@Override
	public void handle(int days) {
		if(days <= 30) {
			System.out.println("OK，主任批准假期（天）："+days);
		}else {
			System.out.println("主任无法批准 "+days+" 天");
			nextHandler.handle(days);
		}
	}
	
}
class schoolmasterHandler extends ChainHandler{

	@Override
	public void handle(int days) {
		if(days >= 360) {
			System.out.println("校长认为假期太长，需要先考虑考虑。");
		}else {
			System.out.println("OK，校长批准假期（天）："+days);
		}
	}
	
}

结果：