public void visit(QueryGroupPatterns group)
{
ArrayList groupJoins = new ArrayList();
Hashtable variableMentionsWithinThisGroup = new Hashtable();
bool allPatternsAreMatchable = true;
foreach (Pattern pattern in group.Patterns)
{
if (!(pattern.GetSubject() is Variable) && !itsResourcesIndexedByNode.Contains(pattern.GetSubject()))
{
allPatternsAreMatchable = false;
}
else if (!(pattern.GetPredicate() is Variable) && !itsResourcesIndexedByNode.Contains(pattern.GetPredicate()))
{
allPatternsAreMatchable = false;
}
else if (!(pattern.GetObject() is Variable) && !itsResourcesIndexedByNode.Contains(pattern.GetObject()))
{
allPatternsAreMatchable = false;
}
}
if (allPatternsAreMatchable)
{
foreach (Pattern pattern in group.Patterns)
{
++itsStatementTableCount;
string tableName = "s" + itsStatementTableCount;
ArrayList constraints = new ArrayList();
bool referencesExternalVariables = false;
if (ProcessPatternTerm(pattern.GetSubject(), tableName, "subjectHash", constraints, variableMentionsWithinThisGroup))
{
referencesExternalVariables = true;
}
if (ProcessPatternTerm(pattern.GetPredicate(), tableName, "predicateHash", constraints, variableMentionsWithinThisGroup))
{
referencesExternalVariables = true;
}
if (ProcessPatternTerm(pattern.GetObject(), tableName, "objectHash", constraints, variableMentionsWithinThisGroup))
{
referencesExternalVariables = true;
}
constraints.Add(tableName + ".graphId=" + itsResourceMap.GetHashCode());
if (itsStatementTableCount > 1)
{
StringBuilder join = new StringBuilder();
if (referencesExternalVariables && itsOptionalNestingDepth > 0)
{
join.Append("LEFT OUTER ");
}
join.Append("JOIN Statements " + tableName + " ON ");
bool doneFirst = false;
foreach (string constraint in constraints)
{
if (constraint != null && constraint.Length > 0)
{
if (doneFirst)
{
join.Append(" AND ");
}
join.Append(constraint);
doneFirst = true;
}
}
groupJoins.Add(join.ToString());
}
else
{
foreach (string constraint in constraints)
{
if (constraint != null && constraint.Length > 0)
{
itsWhereTerms.Add(constraint);
}
}
}
}
itsJoins.AddRange(groupJoins);
}
else
{
if (itsOptionalNestingDepth == 0)
{
NoSolutionIsPossible();
}
}
}