在图中的多个节点下方添加子树

Question

I am using Java JUNG 2.0.1 version. I understand basics of JUNG API.

I have a tree with root vertex as 1 [see Input graph]. Basically, I want to remove an edge (from:1 to:3) ie have sub-tree where root is vertex 3 and add it below vertex 2 and vertex 5 separately [see Output graph].

I used getSubTree() and addSubTree() of TreeUtils.java. But, it gives error with stack trace : java.lang.IllegalArgumentException: Tree must not already contain child abc at edu.uci.ics.jung.graph.DelegateTree.addChild(DelegateTree.java:182) at edu.uci.ics.jung.graph.DelegateTree.addEdge(DelegateTree.java:102) at edu.uci.ics.jung.graph.util.TreeUtils.addFromSubTree(TreeUtils.java:139) at edu.uci.ics.jung.graph.util.TreeUtils.addSubTree(TreeUtils.java:100)

Input graph :

Output graph :

Answer 1

Marco13@ is correct. Graph elements (nodes and edges) are required to be unique; think of them as elements of a set.

If you want two nodes to have the same label (or value, or some other associated data), there are several ways to go about doing this, as discussed here: http://sourceforge.net/apps/trac/jung/wiki/JUNGManual#UserData