Varredura em árvore binária

@Override
    public void preOrder() throws EmptyTreeException {
        if ( isEmpty () )
            throw new EmptyTreeException( this.getClass().getName() );

        preOrder ( getRoot () );
    }

    private void preOrder ( BinaryTreeNode<type> node ) {
        node.visit ();

        if ( node.hasLeftSon () )
            preOrder ( node.getLeftSon () );

        if ( node.hasRightSon () )
            preOrder ( node.getRightSon () );
    }

    @Override
    public void inOrder() throws EmptyTreeException {
        if ( isEmpty () )
            throw new EmptyTreeException( this.getClass().getName() );

        inOrder ( getRoot () );
    }

    private void inOrder ( BinaryTreeNode<type> node ) {
        if ( node.hasLeftSon () )
            inOrder ( node.getLeftSon () );

        node.visit ();

        if ( node.hasRightSon () )
            inOrder ( node.getRightSon () );
    }

    @Override
    public void postOrder() throws EmptyTreeException {
        if ( isEmpty () )
            throw new EmptyTreeException( this.getClass().getName() );

        postOrder ( getRoot () );
    }

    private void postOrder ( BinaryTreeNode<type> node ) {
        if ( node.hasLeftSon() )
            postOrder ( node.getLeftSon () );

        if ( node.hasRightSon() )
            postOrder ( node.getRightSon () );

        node.visit ();
    }