public void generateExpressionsIfNecessary() {
    if (this.viewPathType == ViewPathType.FULL_PATH_LIST
        || this.viewPathType == ViewPathType.PATHS_GROUP) {
      if (this.fullPathList != null) {
        this.expressionsList = new ArrayList<>();
        for (PartialPath path : this.fullPathList) {
          TimeSeriesOperand tsExpression = new TimeSeriesOperand(path);
          this.expressionsList.add(tsExpression);
        }
      }
    } else if (this.viewPathType == ViewPathType.QUERY_STATEMENT) {
      // no nothing. expressions should be set by setExpressionsList
    } else if (this.viewPathType == ViewPathType.BATCH_GENERATION) {
      // source paths has no intoItem. target paths should not be converted to expression.
    }
  }
A class to save all paths' info in targetPaths and sourcePaths except query statement.

<p>fullPathList: CREATE VIEW root.db.device.temp AS root.ln.d.s01 PathGroup: CREATE VIEW
root.db(device.temp, status) AS root.ln(d.s01, wf.abc.s02)
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/view/ViewPaths.java