/// <summary>Adds an outer join descriptor that defines how the streams are related via outer joins. <para /> For joining Count streams, add Count-1 outer join qualifiers. </summary>
/// <param name="outerJoinQualifier">is the type of outer join and the fields in the outer join</param>
/// <returns>from clause</returns>
public FromClause Add(OuterJoinQualifier outerJoinQualifier)
{
OuterJoinQualifiers.Add(outerJoinQualifier);
return(this);
}
/// <summary>Creates a from-clause that lists 2 projected streams joined via outer join. </summary>
/// <param name="stream">first stream in outer join</param>
/// <param name="outerJoinQualifier">qualifies the outer join</param>
/// <param name="streamSecond">second stream in outer join</param>
/// <returns>from clause</returns>
public static FromClause Create(Stream stream, OuterJoinQualifier outerJoinQualifier, Stream streamSecond)
{
return(new FromClause(stream, outerJoinQualifier, streamSecond));
}
/// <summary>Ctor for an outer join between two streams. </summary>
/// <param name="streamOne">first stream in outer join</param>
/// <param name="outerJoinQualifier">type of outer join and fields joined on</param>
/// <param name="streamTwo">second stream in outer join</param>
public FromClause(Stream streamOne, OuterJoinQualifier outerJoinQualifier, Stream streamTwo)
: this(streamOne)
{
Add(streamTwo);
OuterJoinQualifiers.Add(outerJoinQualifier);
}
/// <summary>Renders the from-clause in textual representation. </summary>
/// <param name="writer">to output to</param>
/// <param name="includeFrom">flag whether to add the "from" literal</param>
/// <param name="formatter">for NewLine-whitespace formatting</param>
public void ToEPLOptions(TextWriter writer, EPStatementFormatter formatter, bool includeFrom)
{
String delimiter = "";
if (includeFrom)
{
formatter.BeginFrom(writer);
writer.Write("from");
}
if ((OuterJoinQualifiers == null) || (OuterJoinQualifiers.Count == 0))
{
bool first = true;
foreach (Stream stream in Streams)
{
writer.Write(delimiter);
formatter.BeginFromStream(writer, first);
first = false;
stream.ToEPL(writer, formatter);
delimiter = ",";
}
}
else
{
if (OuterJoinQualifiers.Count != (Streams.Count - 1))
{
throw new ArgumentException("Number of outer join qualifiers must be one less then the number of streams.");
}
bool first = true;
for (int i = 0; i < Streams.Count; i++)
{
Stream stream = Streams[i];
formatter.BeginFromStream(writer, first);
first = false;
stream.ToEPL(writer, formatter);
if (i > 0)
{
OuterJoinQualifier qualCond = OuterJoinQualifiers[i - 1];
if (qualCond.Left != null)
{
writer.Write(" on ");
qualCond.Left.ToEPL(writer, ExpressionPrecedenceEnum.MINIMUM);
writer.Write(" = ");
qualCond.Right.ToEPL(writer, ExpressionPrecedenceEnum.MINIMUM);
if (qualCond.AdditionalProperties.Count > 0)
{
foreach (PropertyValueExpressionPair pair in qualCond.AdditionalProperties)
{
writer.Write(" and ");
pair.Left.ToEPL(writer, ExpressionPrecedenceEnum.MINIMUM);
writer.Write(" = ");
pair.Right.ToEPL(writer, ExpressionPrecedenceEnum.MINIMUM);
}
}
}
}
if (i < Streams.Count - 1)
{
OuterJoinQualifier qualType = OuterJoinQualifiers[i];
writer.Write(" ");
writer.Write(qualType.JoinType.GetText());
writer.Write(" outer join");
}
}
}
}
