package yqlib import ( "fmt" "container/list" logging "gopkg.in/op/go-logging.v1" ) type DataTreeNavigator interface { // given a list of CandidateEntities and a expressionNode, // this will process the list against the given expressionNode and return // a new list of matching candidates GetMatchingNodes(matchingNodes *list.List, expressionNode *ExpressionNode) (*list.List, error) } type dataTreeNavigator struct { } func NewDataTreeNavigator() DataTreeNavigator { return &dataTreeNavigator{} } func (d *dataTreeNavigator) GetMatchingNodes(matchingNodes *list.List, expressionNode *ExpressionNode) (*list.List, error) { if expressionNode == nil { log.Debugf("getMatchingNodes - nothing to do") return matchingNodes, nil } log.Debugf("Processing Op: %v", expressionNode.Operation.toString()) if log.IsEnabledFor(logging.DEBUG) { for el := matchingNodes.Front(); el != nil; el = el.Next() { log.Debug(NodeToString(el.Value.(*CandidateNode))) } } log.Debug(">>") handler := expressionNode.Operation.OperationType.Handler if handler != nil { return handler(d, matchingNodes, expressionNode) } return nil, fmt.Errorf("Unknown operator %v", expressionNode.Operation.OperationType) }