Constructor that uses Constructors

Here is the constructor. This constructor creates two objects by using their constructors. References to the new objects are copied into the corresponding instance variables of the new Tree.

The int variables are initialized in the usual way. A toString() method has been added.

The height of the tree is the height of the trunk plus the height of the branches. Include additional attributes in the toString() method if you wish.

// Tree.java
//
public class Tree
{
  // instance variables
  private double x, y, z;
  private Cone branches;
  private Cylinder trunk;  
  
  // constructor
  public Tree( double trRad, double trHeight, double brRad, double brHeight, double x, double y, double z)
  {
    trunk = new Cylinder( trRad, trHeight );
    branches = new Cone( brRad, brHeight );
    this.x = x; this.y = y; this.z = z;
  }
  
  // methods
  public String toString()
  {
    double totalHeight = branches.getHeight() + trunk.getHeight();
    double width = branches.getRadius();
    return "Tree. Height: "  + totalHeight + ", width: " + width ;
  }
  
  // more methods to come ...
  
}

A wise programmer tests early and often. Here is a testing class:

// TreeTester.java
//
public class TreeTester
{
  public static void main( String[] args )
  {
    double trunkR = 1.0, trunkH = 5.0, branchR = 25.0, branchH = 50.0 ;
    
    Tree myTree = new Tree( trunkR, trunkH, branchR, branchH, 1, 2, 3  );
    System.out.println("myTree: " + myTree + "\n");
  }
}

When you compile TreeTester.java the compiler will also compile Tree.java, Cone.java, and Cylinder.java if they in the same directory and need to be compiled. When TreeTester.class is run, the run-time system will use the class files when needed.

C:\JSource> javac TreeTester.java
C:\JSource> dir
Mode                LastWriteTime         Length Name
----                -------------         ------ ----
-a----         9/1/2017  11:32 PM           1179 Cone.class
-a----         9/1/2017  11:25 PM            936 Cone.java
-a----        8/30/2017   7:15 PM            741 Cylinder.class
-a----        8/29/2017   8:26 PM            884 Cylinder.java
-a----        9/22/2019  12:04 PM           1073 Tree.class
-a----        9/22/2019  12:03 PM            693 Tree.java
-a----        9/22/2019  12:20 PM            981 TreeTester.class
-a----        9/22/2019  12:03 PM            314 TreeTester.java

The program prints out:

C:\JSource> java TreeTester
myTree: Tree. Height: 55.0, width: 25.0

Here is a picture of a BlueJ version of the same code: BlueJ Tree