[JAVA][Beginning Java 8 Games Development]

Chapter 12 ■ Setting Boundaries for Your Action Figure in 2D: Using the Node Class LocalToParent Attribute
Modifying the iBagel Instantiation: Adding a Java this Keyword to the Method Call
Open up your .createGameActors() method structure using the + expand icon on the left side of NetBeans. Add a
this keyword at the “head” or front of the list of parameters that you are passing into the Bagel() constructor method call.
Your newly revised Java statement should look like the following code, which is also shown highlighted in Figure 12-5:
iBagel = new Bagel(this, "M150 0 L75 200 L225 200 Z", 0,0, iB0,iB1,iB2,iB3,iB4,iB5,iB6,iB7,iB8);
Figure 12-5. Modify the iBagel instantiation to add a Java this keyword to the Bagel() constructor method parameters
As you can see in Figure 12-5, your Java code is error-free, which means that you have now passed a copy of your
InvinciBagel.java class’s (or the object created by it, however you prefer to look at it) context into the Bagel class (or
more precisely, into the object which is created by your use of the Bagel() constructor method). What is contained
in the digital context structure of the this object is beyond the scope of a beginner book, but suffice it to say that the
this keyword will pass over a complete structural reference to an object. This reference contains all of the contextual
information which would be needed to give the object that it is being passed to enough information to be able to put
everything into “digital perspective” (context) regarding the class that is passing the this reference object over, in our
case, this will be the InvinciBagel class (object) passing contextual information about itself to the Bagel class (object).
This will include your object structure (variables, constants, methods, etc.) for the object as well as state information
relating to more complex things that relate to use of system memory and thread usage. Think of passing one object’s
context information to another object using the Java this keyword as wiring them together, so to speak, so that your
receiving object can peer into the sending object by using the this object reference.
Now that the this reference (contextual object) for the InvinciBagel class (object) has been passed to the Bagel
class (object) by using the Java this keyword inside of the Bagel() constructor method, we have now create a far more
industry standard link between these two classes. We can now proceed to change our Bagel .update() method so that
it uses the new .is() method calls to get the four different Boolean variable values (states) from the InvinciBagel object
reference that it now has. We will need this data to be able to move our InvinciBagel character around on the screen.
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