Tree Implementations - Data Structures and Abstractions with Java - page 608

if ((leftTree != null ) && !leftTree.isEmpty())
root.setLeftChild(leftTree.root);
if ((rightTree != null ) && !rightTree.isEmpty())
{

if (rightTree != leftTree)
root.setRightChild(rightTree.root);
else
root.setRightChild(rightTree.root.copy());
} // end if
if ((leftTree != null ) && (leftTree != this ))
leftTree.clear();
if ((rightTree != null ) && (rightTree != this ))
rightTree.clear();
} // end privateSetTree

Question 2 At the end of the implementation of privateSetTree , can you set rightTree to
null instead of invoking clear ? Explain.

Accessor and Mutator Methods
24.9

The public methods getRootData , isEmpty , and clear are easy to implement. In addition
to these methods, we define several protected methods— setRootData , setRootNode , and
getRootNode —that will be useful in the implementation of a subclass. The implementa-
tions of these methods follow:

public T getRootData()
{

T rootData = null ;
if (root != null )
rootData = root.getData();
return rootData;
} // end getRootData
public boolean isEmpty()
{

VideoNote

Binary tree operations

return root == null ;
} // end isEmpty
public void clear()
{

root = null ;
} // end clear
protected void setRootData(T rootData)
{

root.setData(rootData);
} // end setRootData
protected void setRootNode(BinaryNodeInterface<T> rootNode)
{

root = rootNode;
} // end setRootNode
protected BinaryNodeInterface<T> getRootNode()
{

return root;
} // end getRootNode