// build the new treemodel by evaluating the preconditions
TreeEvaluation treeEval = new TreeEvaluation();
GenericTreeModel treeModel = new GenericTreeModel();
CourseNode rootCn = userCourseEnv.getCourseEnvironment().getRunStructure().getRootNode();
NodeEvaluation rootNodeEval = rootCn.eval(userCourseEnv.getConditionInterpreter(), treeEval);
TreeNode treeRoot = rootNodeEval.getTreeNode();
treeModel.setRootNode(treeRoot);
// find the treenode that corresponds to the node (!= selectedTreeNode since
// we built the TreeModel anew in the meantime
TreeNode newCalledTreeNode = treeEval.getCorrespondingTreeNode(courseNode);
if (newCalledTreeNode == null) {
// the clicked node is not visible anymore!
// if the new calculated model does not contain the selected node anymore
// (because of visibility changes of at least one of the ancestors
// -> issue an user infomative msg
// nclr: the new treemodel, not visible, no selected nodeid, no
// calledcoursenode, no nodeconstructionresult
nclr = new NodeClickedRef(treeModel, false, null, null, null);
} else {
// calculate the NodeClickedRef
// 1. get the correct (new) nodeevaluation
NodeEvaluation nodeEval = (NodeEvaluation) newCalledTreeNode.getUserObject();
if (nodeEval.getCourseNode() != courseNode) throw new AssertException("error in structure");
if (!nodeEval.isVisible()) throw new AssertException("node eval not visible!!");
// 2. start with the current NodeEvaluation, evaluate overall accessiblity
// per node bottom-up to see if all ancestors still grant access to the
// desired node
boolean mayAccessWholeTreeUp = mayAccessWholeTreeUp(nodeEval);
String newSelectedNodeId = newCalledTreeNode.getIdent();
if (!mayAccessWholeTreeUp) {
// we cannot access the node anymore (since e.g. a time constraint
// changed), so give a (per-node-configured) explanation why and what
// the access conditions would be (a free form text, should be
// nontechnical).