TableGroup.java

TableGroupImpl ... {
  private final TableReference primaryRef;
  private final BiFunction<TableReference,String,TableReferenceJoin> joinCreator;

	private List<TableReferenceJoin> tableJoins;
  ...

  @Override
	public TableReference resolveTableReference(String tableExpression) {
    if ( primaryRef... ) {
      ...
    }

    TableReferenceJoin existing = null;
    if ( tableJoins == null ) {
      tableJoins = new ...;
    }
    else {
      for (TableReferenceJoin trj : tableJoins ) {
        if ( ... ) {
          existing = trj;
          break;
        }
      }
    }

    if ( existing != null ) {
      return existing;
    }

    final TableReferenceJoin trj = joinCreator.apply( primaryRef, tableExpression );
    tableJoins.add( trj );
    return trj;
  }
}