code: package it.unibz.inf.ontop.iq.node.normalization;
  
  import it.unibz.inf.ontop.iq.IQTree;
  import it.unibz.inf.ontop.iq.IQTreeCache;
  import it.unibz.inf.ontop.iq.node.LeftJoinNode;
  import it.unibz.inf.ontop.utils.VariableGenerator;
  
  public interface LeftJoinNormalizer {
  
  
      IQTree normalizeForOptimization(LeftJoinNode ljNode, IQTree initialLeftChild, IQTree initialRightChild,
                                      VariableGenerator variableGenerator,
                                      IQTreeCache treeCache);
  }
  