public boolean hasNext() {
            while (next == null && collector.hasNext()) {
              IDeviceSchemaInfo temp = collector.next();
              if (filterVisitor.process(showDevicesPlan.getSchemaFilter(), temp)) {
                next = temp;
              }
            }
            return next != null;
          }
Currently, this method is only used for pin node get from mNodeCache

@param node
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/pbtree/MTreeBelowSGCachedImpl.java