如何使我的程序将下面的示例创建限制为4个，以便当我尝试创建第五个学校时，它会显示一条错误消息，“学校无法注册，已达到最大值”。一如既往地谢谢你

public class Driver {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Header h1 = new Header();
        h1.schoolHeader();
        School s1 = new School("Pascoe Vale High School", "101");
        School s2 = new School("North Melbourne Primary School", "102");
        School s3 = new School("St Aloysuis College", "103");
        School s4 = new School("Coburg High School", "104");
        School s5 = new School("Chuka Nwobi High School", "105");
    }
}

class School {
    public static int objCount = 0;
    private static String regId;
    private String name;

    School(String name, String regId) {
        this.name = name;
        this.regId = regId;
        System.out.println("***Successfully registered " + getName());
        objCount++;
    }

    public void registerHeader() {
        System.out.println("--- Registering Participating Schools---");
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getRegId() {
        return regId;
    }
    public void setRegId(String regId) {
        this.regId = regId;
    }
}