public List<Expression> copyDerivedExpressions(Map alreadyDone) {
   if (this.derivedExpressions == null) {
     return null;
   }
   List<Expression> derivedExpressionsCopy;
   synchronized (this) {
     derivedExpressionsCopy = new ArrayList(this.derivedExpressions);
   }
   List<Expression> result = new ArrayList(derivedExpressionsCopy.size());
   for (Expression exp : derivedExpressionsCopy) {
     result.add(exp.copiedVersionFrom(alreadyDone));
   }
   return result;
 }
  /**
   * INTERNAL: Used in case outer joins should be printed in FROM clause. Each of the additional
   * tables mapped to expressions that joins it.
   */
  public Map additionalExpressionCriteriaMap() {
    if (getDescriptor() == null) {
      return null;
    }

    HashMap tablesJoinExpressions = new HashMap();
    Vector tables = getDescriptor().getTables();
    // skip the main table - start with i=1
    int tablesSize = tables.size();
    if (shouldUseOuterJoin()) {
      for (int i = 1; i < tablesSize; i++) {
        DatabaseTable table = (DatabaseTable) tables.elementAt(i);
        Expression joinExpression =
            (Expression) getDescriptor().getQueryManager().getTablesJoinExpressions().get(table);
        joinExpression = getBaseExpression().twist(joinExpression, this);
        tablesJoinExpressions.put(table, joinExpression);
      }
    }
    if (isUsingOuterJoinForMultitableInheritance()) {
      List childrenTables = getDescriptor().getInheritancePolicy().getChildrenTables();
      tablesSize = childrenTables.size();
      for (int i = 0; i < tablesSize; i++) {
        DatabaseTable table = (DatabaseTable) childrenTables.get(i);
        Expression joinExpression =
            (Expression)
                getDescriptor()
                    .getInheritancePolicy()
                    .getChildrenTablesJoinExpressions()
                    .get(table);
        joinExpression = getBaseExpression().twist(joinExpression, this);
        tablesJoinExpressions.put(table, joinExpression);
      }
    }

    return tablesJoinExpressions;
  }
  /**
   * INTERNAL: Used in case outer joins should be printed in FROM clause. Each of the additional
   * tables mapped to expressions that joins it.
   */
  public Map additionalExpressionCriteriaMap() {
    if (getDescriptor() == null) {
      return null;
    }

    HashMap tablesJoinExpressions = null;
    if (isUsingOuterJoinForMultitableInheritance()) {
      tablesJoinExpressions = new HashMap();
      List childrenTables = getDescriptor().getInheritancePolicy().getChildrenTables();
      for (int i = 0; i < childrenTables.size(); i++) {
        DatabaseTable table = (DatabaseTable) childrenTables.get(i);
        Expression joinExpression =
            getDescriptor().getInheritancePolicy().getChildrenTablesJoinExpressions().get(table);
        if (getBaseExpression() != null) {
          joinExpression = getBaseExpression().twist(joinExpression, this);
        } else {
          joinExpression = twist(joinExpression, this);
        }
        tablesJoinExpressions.put(table, joinExpression);
      }
    }

    return tablesJoinExpressions;
  }