public abstract class AbstractBuy {	public abstract void doBuy();}

public class BuilderUtil {	public String message; 	public boolean flag;		private boolean isCotinue=true;	/**是否可以购买**/	public BuilderUtil isBuy(boolean f){		if(isCotinue){			if(f){				message="可以购买";				flag=true;				isCotinue=true;			}else{				message="不可以购买";				flag=false;				isCotinue=false;			}		}		return this;	}	/**是否有足够的钱买**/	public BuilderUtil isMoney(double fy){		if(isCotinue){			if(fy >=1000){				message="钱不够";				flag=false;				isCotinue=false;			}else{				message="有足够的钱";				flag=true;				isCotinue=true;			}		}		return this;	}		public BuilderUtil isAvalioble(double money,AbstractBuy buy){		buy.doBuy();		return this;	}	public String getMessage() {		return message;	}	public void setMessage(String message) {		this.message = message;	}	public boolean isFlag() {		return flag;	}	public void setFlag(boolean flag) {		this.flag = flag;	}}

测试

public class BuilderTest {	public static void main(String[] args) {		BuilderUtil builderUtil=new BuilderUtil();		BuilderUtil builder=builderUtil.isBuy(false).isMoney(10000);		System.out.println(builder.getMessage());	}}