/**
* Returns the index of the specified child in this node's child array. If the specified node is
* not a child of this node, returns <code>-1</code>. This method performs a linear search and is
* O(n) where n is the number of children.
*
* @param aChild the TreeNode to search for among this node's children
* @exception IllegalArgumentException if <code>aChild</code> is null
* @return an int giving the index of the node in this node's child array, or <code>-1</code> if
* the specified node is a not a child of this node
*/
public int getIndex(TreeNode aChild) {
if (aChild == null) {
throw new IllegalArgumentException("argument is null");
}
if (!isNodeChild(aChild)) {
return -1;
}
return children.indexOf(aChild); // linear search
}
