Interface ResultListRowTransformer<S,Q extends FlexibleRelationalPathBase<R>,R>

Type Parameters:
S - schema type
Q - type of entity path
R - row type related to the ResultListRowTransformer

public interface ResultListRowTransformer<S,Q extends FlexibleRelationalPathBase<R>,R>
Helps with row transformation of result lists, possibly in stateful context. This kind of transformation still has access to low-level row data if necessary. Typical example is container's owner OID which is lost in the container itself. For example, row-by-row transformation can collect information for some additional processing which can be executed by implementing finishTransformation(). Alternatively, the result list of tuples can be processed first with beforeTransformation(java.util.List<com.querydsl.core.Tuple>, Q), for instance to fetch owner objects for the whole container list in a single query. The reason for this is that transform(com.querydsl.core.Tuple, Q) already needs to return actual containers from the owner object. Leaving this fetch to finishTransformation() would require this method to transform the list again and replace "bare" containers with the real ones from owner objects. Finish method is useful when the objects in the final result list needs to be enriched, but not when they need to be replaced. (If this is necessary later, just add result list as parameter and returned value as well.)
  • Method Summary

    Modifier and Type
    Method
    Description
    default void
    beforeTransformation(List<com.querydsl.core.Tuple> rowTuples, Q entityPath)
    This allows preprocessing of results before the transformation.
    default void
    This method is called after all the rows were transformed and allows for additional final shake-up for more complex stateful transformations.
    transform(com.querydsl.core.Tuple rowTuple, Q entityPath)
    Transforms row tuple to the midPoint object.
  • Method Details

    • beforeTransformation

      default void beforeTransformation(List<com.querydsl.core.Tuple> rowTuples, Q entityPath) throws SchemaException
      This allows preprocessing of results before the transformation. One example is to load owner objects for containers.
      Throws:
      SchemaException
    • transform

      S transform(com.querydsl.core.Tuple rowTuple, Q entityPath)
      Transforms row tuple to the midPoint object.
    • finishTransformation

      default void finishTransformation() throws SchemaException
      This method is called after all the rows were transformed and allows for additional final shake-up for more complex stateful transformations.
      Throws:
      SchemaException