将Java建造者模式转为Apex时遇变量访问问题求助

问题概述 #

将Java建造者模式代码转换为Apex时，在ScrewBuilder类中调用chiller.setCoolingCapacity()等方法时提示变量不可见，即使将字段改为public也无法解决。

核心错误原因 #

1. Apex默认访问修饰符为private：Java中未指定修饰符的成员是包级私有，但Apex中未指定修饰符的成员默认是private。因此ChillerBuilder中的chiller变量和getChiller()方法默认是private，导致子类ScrewBuilder无法直接访问chiller，Director类也无法调用getChiller()。
2. Math.round()参数类型不匹配：Apex的Math.round()仅接受Decimal类型参数，直接传入double值会编译报错。
3. 部分成员未明确访问修饰符：未指定修饰符的字段/方法会因Apex默认规则导致访问权限问题。

修正后的完整代码 #

1. RefrigerationType枚举 #

public enum RefrigerationType {
    R134, R12
}

2. Chiller实体类 #

public class Chiller {
    private Double coolingCapacity;
    private Double compressorPower;
    private Double EER;
    private RefrigerationType refrigerationType;

    public void setCoolingCapacity(Double coolingCapacity) {
        this.coolingCapacity = coolingCapacity;
    }

    public void setCompressorPower(Double compressorPower) {
        this.compressorPower = compressorPower;
    }

    public void setEER(Double EER) {
        this.EER = EER;
    }

    public void setRefrigerationType(RefrigerationType refrigerationType) {
        this.refrigerationType = refrigerationType;
    }

    public override String toString() {
        Integer roundedEER = Math.round(Double.valueOf(EER).toDecimal());
        return 'Chiller [Cooling capacity = ' + coolingCapacity + 
               ' compressor power input = ' + compressorPower + 
               ' EER = ' + roundedEER +
               ' refrigeration type is ' + refrigerationType + ']';
    }
}

3. ChillerBuilder抽象类 #

public abstract class ChillerBuilder {
    protected Chiller chiller;
    public void createChiller() {
        chiller = new Chiller();
    }

    public abstract void buildCapacity();
    public abstract void buildCompressorPower();
    public abstract void buildEER();
    public abstract void buildRefrigerationType();

    public Chiller getChiller() {
        return chiller;
    }
}

4. ScrewBuilder具体建造者 #

public class ScrewBuilder extends ChillerBuilder {
    public override void buildCapacity() {
        Double capacity = ((12-7)*1042*1000/3600);
        chiller.setCoolingCapacity(capacity);
    }

    public override void buildCompressorPower() {
        Double power = ((12-7)*1042*1000/3600)*0.83;
        chiller.setCompressorPower(power);
    }

    public override void buildEER() {
        Double eer = ((12-7)*1042*1000/3600)/(((12-7)*1042*1000/3600)*0.83);
        chiller.setEER(eer);
    }

    public override void buildRefrigerationType() {
        chiller.setRefrigerationType(RefrigerationType.R134);
    }
}

5. Director指挥者类 #

public class Director {
    private ChillerBuilder builder;

    public void setBuilder(ChillerBuilder b) {
        builder = b;
    }

    public Chiller buildChiller() {
        builder.createChiller();
        builder.buildCapacity();
        builder.buildCompressorPower();
        builder.buildEER();
        builder.buildRefrigerationType();
        return builder.getChiller();
    }
}

关键修改说明 #

1. 将ChillerBuilder中的chiller变量改为protected，确保子类ScrewBuilder可以访问该成员。
2. 将ChillerBuilder的getChiller()方法改为public，让Director类能够调用获取构建好的Chiller实例。
3. 修正Chiller类toString()中的Math.round()调用，将Double转换为Decimal后再传入，匹配方法参数要求。
4. 明确所有成员的访问修饰符，避免Apex默认private规则带来的访问权限问题。
5. 调整方法命名为Apex标准驼峰命名法，提升代码可读性。

内容的提问来源于stack exchange，提问作者user20695159