/// <summary>
/// Executes this operation
/// </summary>
/// <param name="rows">Rows in pipeline. These are only used if a left part of the join was not specified.</param>
/// <returns></returns>
public override IEnumerable <Row> Execute(IEnumerable <Row> rows)
{
Initialize();
Guard.Against(left == null, "Left branch of a join cannot be null");
Guard.Against(right == null, "Right branch of a join cannot be null");
var leftRows = new EventRaisingEnumerator(left, left.Execute(leftRegistered ? null : rows)).GetEnumerator();
leftRows.MoveNext();
var leftRow = (Row)leftRows.Current;
var rightRows = new EventRaisingEnumerator(right, right.Execute(null)).GetEnumerator();
rightRows.MoveNext();
var rightRow = (Row)rightRows.Current;
while (leftRow != null && rightRow != null)
{
var match = MatchJoinCondition(leftRow, rightRow);
Row mergedRow = null;
if (match == 0)
{
mergedRow = MergeRows(leftRow, rightRow);
leftRow = leftRows.MoveNext()
? (Row)leftRows.Current
: null;
rightRow = rightRows.MoveNext()
? (Row)rightRows.Current
: null;
}
else if (match < 0)
{
if ((JoinType & JoinType.Left) != 0)
{
mergedRow = MergeRows(leftRow, new Row());
}
else
{
LeftOrphanRow(leftRow);
}
leftRow = leftRows.MoveNext()
? (Row)leftRows.Current
: null;
}
else if (match > 0)
{
if ((JoinType & JoinType.Right) != 0)
{
mergedRow = MergeRows(new Row(), rightRow);
}
else
{
RightOrphanRow(rightRow);
}
rightRow = rightRows.MoveNext()
? (Row)rightRows.Current
: null;
}
if (mergedRow != null)
{
yield return(mergedRow);
}
}
if (leftRow == null && rightRow != null && (JoinType & JoinType.Right) != 0)
{
yield return(MergeRows(new Row(), rightRow));
}
}
/// <summary>
/// Executes this operation
/// </summary>
/// <param name="rows">Rows in pipeline. These are only used if a left part of the join was not specified.</param>
/// <returns></returns>
public override IEnumerable <Row> Execute(IEnumerable <Row> rows)
{
Initialize();
Guard.Against(left == null, "Left branch of a join cannot be null");
Guard.Against(right == null, "Right branch of a join cannot be null");
var matchedRightRows = new Dictionary <Row, object>();
var rightEnumerable = new CachingEnumerable <Row>(
new EventRaisingEnumerator(right, right.Execute(null))
);
var execute = left.Execute(leftRegistered ? null : rows);
foreach (Row leftRow in new EventRaisingEnumerator(left, execute))
{
var leftNeedOuterJoin = true;
currentLeftRow = leftRow;
foreach (Row rightRow in rightEnumerable)
{
currentRightRow = rightRow;
if (MatchJoinCondition(leftRow, rightRow))
{
leftNeedOuterJoin = false;
matchedRightRows[rightRow] = null;
yield return(MergeRows(leftRow, rightRow));
}
}
if (leftNeedOuterJoin)
{
var emptyRow = new Row();
emptyRow[IsEmptyRowMarker] = IsEmptyRowMarker;
currentRightRow = emptyRow;
if (MatchJoinCondition(leftRow, emptyRow))
{
yield return(MergeRows(leftRow, emptyRow));
}
else
{
LeftOrphanRow(leftRow);
}
}
}
foreach (Row rightRow in rightEnumerable)
{
if (matchedRightRows.ContainsKey(rightRow))
{
continue;
}
currentRightRow = rightRow;
var emptyRow = new Row();
emptyRow[IsEmptyRowMarker] = IsEmptyRowMarker;
currentLeftRow = emptyRow;
if (MatchJoinCondition(emptyRow, rightRow))
{
yield return(MergeRows(emptyRow, rightRow));
}
else
{
RightOrphanRow(rightRow);
}
}
}