PezDispenser.java... What is happening?

Hey,

So we have a class called PezDispenser. The class holds onto a variable called mCharacterName. M is used to define that it's a member variable. Meaning any method in the class will be able to use the value of this variable once set. It's private so only methods within this class can use it. So in order to access the variable, I need to instantiate or create the class. That is what PezDispenser dispenser = new PezDispenser(); is for. More on that in a minute.

If I had mCharacterName defined in a method. The variable would only exist while the method was being run. By defining it above as a member variable or class owned variable, it's available while the class exists. Not just while running a particular method.

Next, we have a pezDispenser constructor. I know this because the constructor has the same name as the class. This means that when the class is created. The constructor is what creates it. Every class has a constructor, but if you do not define one. A no argument default constructor is called. Which doesn't do anything. It's there even if you don't see it. When you see a constructor it's because when the class is first built, it needs to be built a specific way. We do this using the constructor. I need to pass a String into the constructor, a characterName of type String. When the class is instantiated using PezDispenser dispenser = new PezDispenser(); I pass in a string name. This way, when the class is built for the first time. It sets the mCharacterName to whatever i passed into the constructor when I instantiated the class. Like below

PezDispenser dispenser = new PezDispenser('Ryan'); This creates the class below, and the constructor runs and assigns mCharacterName to my name, Ryan.

Then I have a method inside the class PezDispenser, that is getCharacterName(). When I call this method from the instantiated class, I can use the dot notation.

PezDispenser dispenser = new PezDispenser('Ryan'); -- creates the class and sets mCharacterName to Ryan via constructor

use the reference "dispenser" from the line above. To call getCharacterName.

dispenser.getCharacterName() -- this will return Ryan. Because when the class was created, I passed in Ryan as the characterName. Which was assigned to mCharacterName name by the constructor. The variable is private, so I can't just call it like a static variable. I need to instantiate the class, Call a method of that class because remember. Since it's private, only methods within the class can access the variable. So I instantiate the class. Set characterName to my name. Then I use dot notation using the reference to the class and the method in that class, to call the private member variable mCharacterName. This value get's passed back to the class I am working in and wallah, I have what I need.

Does this help clear up your confusion? At least for now? Let me know if not, because it is a concept hard to explain.

public class PezDispenser { 
      private String mCharacterName;

      public PezDispenser(String characterName) { 
             mCharacterName = characterName; 
}

      public String getCharacterName() {
           return mCharacterName;
}

Great explanation, Ryan !!!! THis helps a lot ...

Thank you Ryan. This helps me understand this alot better. :D