人的特色只有好人與坏人嗎?

有位仁兄在Java版的回應中問了我這樣一個問題，這問題是多麼富有哲學性，但既然在Java板出現了，就一定要認真地用Java的方式來回答。

話說，人類是萬物之靈，所以人類也是物件的一種。然而要具體形容一個人，除了外觀，當然還有道德、職業、學經歷、聲望這些因素等等…這些要素，在還沒有能夠具體形容這
些要素前，我們能做的，就是暫時將人類塑造為一個簡陋的抽象類別。

package universe.earth;

public abstract class Human {
protected boolean isNormal;
protected boolean isGoodGuy;
protected String sex;
protected double weight;
protected double height;
protected double BMI;
public Human(){}
public abstract boolean IsNormal(boolean eyebrow);
public abstract boolean IsGoodGuy(String skill);
public abstract void setBMI(double weight, double height); }

基本上，人類又可分為帶把與沒帶把的！所以我們接下來就要實做男人類別(帶把的)，這個類別繼承自Human這個抽象類別。

package universe.earth;

public class Male extends Human{

// Of course, this a male class
public Male(){
sex = "male";
this.isNormal = true;
this.isGoodGuy = false; // 人心險惡，先認為不是好人吧！
}

// Is his look normal?
public boolean IsNormal(boolean eyebrow){
if(eyebrow){
this.isNormal = true;
}else{
this.isNormal = false;
}
return isNormal;
}

// Is he a good guy?
public boolean IsGoodGuy(String skill){
if(skill == null || skill.equalsIgnoreCase("java")){
this.isGoodGuy = true;
}else{
this.isGoodGuy = false; // Are you a C# user?;
}
return isGoodGuy;
}

// Check his body is strong, weak, or normal.
public void setBMI(double weight, double height){
this.weight = weight;
this.height = height;
BMI = 10000*weight/Math.pow(height, 2);
}

// overridden toString()
public String toString(){
String description = "He is a " + sex +".\n";
if(isNormal && isGoodGuy && BMI >0){
description += "Good! You should make friend with him.";
}else if(!isNormal && isGoodGuy && BMI >0){
description += "He might be a good friend, but don't laught at his eyebow.";
}else if(!isNormal && !isGoodGuy && BMI >0){
description += "Please, he's just with no eyebrow!";
}else if(BMI <> 0){
description += "You might win at this fight!";
}else if(BMI > 24.9){
description += "Run! Frost! Run!";
}else {
description += "It's a even fight!";
}
return description+"\n";
}
}

好！我們做到這，我們已經可以基於一個人有沒有眉毛、專長、以及BMI決定這個人好不好相處。為了簡單測試，所以我們開始將這個male類別實例化。

package universe.earth;

public class JudgeHuman {
public final static void main(String[] args){
Male thisGuy = new Male();
// 路上兩人相見，不熟悉！
System.out.println("You haven't analyze who he is...");
System.out.println(thisGuy.toString());
// 然後你推測他的身高體重，算出他的BMI...
thisGuy.setBMI(100,183);
System.out.println("After you know his BMI...");
System.out.println(thisGuy.toString());
// 然後你又看了一下他的臉，發現他沒有眉毛！
thisGuy.IsNormal(false);
System.out.println("After you analyze his face...");
System.out.println(thisGuy.toString());
// 最後他告訴你，他原來是個java程式設計師！
thisGuy.IsGoodGuy("java");
System.out.println("After you know his skills...");
System.out.println(thisGuy.toString());
}
}

將這個Java application執行後的結果如下：

You haven't analyze who he is...
He is a male.
It's a even fight!

After you know his BMI...
He is a male.
Run! Frost! Run!

After you analyze his face...
He is a male.
Please, he's just with no eyebrow!

After you know his skills...
He is a male.
He might be a good friend, but don't laught at his eyebow.


所以，最後要回答的結論就是…「人的特色當然不是只有好人或壞人囉！」