tree in java

Can you help me to draw the tree? First we assign the parent node. when child node(x) come we must check the condition. there are three condition such as x<5,5<=x<10 and 10<=x<15 after that we have to add the child in order to condition. Here we have more than two children. After that we want to calculate the average of children and create a parent which average of children. Like following tree.

            (3+7+12)/3=7(root)
            /   |   \
           x<5   /          |    \   10<=x<15
          /         5<=x<10 |      \
    /           |       \
      (1+2+3)/3= 3         (6+8)/2=7     (11+13)/2 =12
    |             /  \             / \
         /  |  \             /    \       /   \
        /   |   \               /      \         /     \
        1   2   3              6        8       11     13