code: private void initFilter() {
          EntityMetadata metadata = KunderaMetadataManager.getEntityMetadata(kunderaMetadata, entityClass);
          Metamodel metaModel = kunderaMetadata.getApplicationMetadata().getMetamodel(getPersistenceUnit());
          EntityType entityType = metaModel.entity(entityClass);
  
          if (null == filter) {
              List<String> clauses = new ArrayList<String>();
              addDiscriminatorClause(clauses, entityType);
              return;
          }
          WhereClause whereClause = KunderaQueryUtils.getWhereClause(getJpqlExpression());
  
          KunderaQueryUtils.traverse(whereClause.getConditionalExpression(), metadata, kunderaMetadata, this, false);
  
          for (Object filterClause : filtersQueue) {
  
              if (!(filterClause instanceof String)) {
                  onTypedParameter(((FilterClause) filterClause));
              }
  
          }
  
          addDiscriminatorClause(null, entityType);
      }
docs: Inits the filter.