targetTreeComponent=treeMapperMigration.m_oldTargetTree;
m_table=Maps.newHashMap();
List<String> mapList=old.getMapList();
Transform transform=new Transform();
for (String line : mapList) {
Mapping m = MapStringFormat.parse(line);
String targetDE=m.getTargetPath().toString();
String expr=m.getExpression();
Node target=targetTreeComponent.findNode_expandTreeIfNotExist(targetDE);
if(target!=null)m_mappedTargetSet.add(target);
Set<Node> delist=Utils.getSourceExpressionList(sourceTreeComponent, expr, transform);
if(delist==null)delist=Sets.newHashSet();
m_mappedSourceSet.addAll(delist);