@Override
public void meet(SqlCase node) throws RuntimeException {
super.meet(node);
List<Entry> entries = node.getEntries();
for (SqlCase.Entry e : entries) {
if (e.getCondition() instanceof SqlNull) {
node.removeEntry(e);
} else if (e.getCondition() instanceof FalseValue) {
node.removeEntry(e);
} else if (e.getCondition() instanceof TrueValue) {
node.truncateEntries(e);
break;
}
}
entries = node.getEntries();
if (entries.isEmpty()) {
replace(node, new SqlNull());
} else if (entries.size() == 1) {
Entry entry = entries.get(0);
if (entry.getCondition() instanceof TrueValue) {
replace(node, entry.getResult().clone());
} else if (entry.getCondition() instanceof FalseValue) {
replace(node, new SqlNull());
} else if (entry.getCondition() instanceof SqlNot) {
SqlNot not = (SqlNot) entry.getCondition();
if (not.getArg() instanceof SqlIsNull) {
SqlIsNull is = (SqlIsNull) not.getArg();
if (is.getArg().equals(entry.getResult())) {
replace(node, entry.getResult().clone());
}
}
}
}
}
@Override
public void meet(SqlIsNull node) throws RuntimeException {
super.meet(node);
SqlExpr arg = node.getArg();
if (arg instanceof SqlNull) {
replace(node, new TrueValue());
} else if (arg instanceof SqlConstant<?>) {
replace(node, new FalseValue());
} else if (arg instanceof SqlCase) {
SqlExpr rep = null;
SqlExpr prev = null;
SqlCase scase = (SqlCase) arg;
for (Entry entry : scase.getEntries()) {
SqlExpr condition = entry.getCondition();
if (rep == null) {
rep = and(condition.clone(), isNull(entry.getResult().clone()));
prev = not(condition.clone());
} else {
rep =
or(rep, and(and(prev.clone(), condition.clone()), isNull(entry.getResult().clone())));
prev = and(prev, not(condition.clone()));
}
}
replace(node, or(rep, prev.clone()));
}
}
@Override
public void meet(SqlCompare node) throws RuntimeException {
super.meet(node);
SqlExpr left = node.getLeftArg();
SqlExpr right = node.getRightArg();
if (left instanceof SqlNull || right instanceof SqlNull) {
replace(node, new SqlNull());
}
}
@Override
public void meet(SelectQuery node) throws RuntimeException {
super.meet(node);
List<SqlExpr> filters = node.getFilters();
for (int i = filters.size() - 1; i >= 0; i--) {
if (filters.get(i) instanceof TrueValue) {
node.removeFilter(filters.get(i));
}
}
}
@Override
public void meet(SqlLowerCase node) throws RuntimeException {
super.meet(node);
if (node.getArg() instanceof SqlNull) {
replace(node, new SqlNull());
} else if (node.getArg() instanceof SqlConstant) {
SqlConstant arg = (SqlConstant) node.getArg();
String lower = arg.getValue().toString().toLowerCase(Locale.US);
replace(node, str(lower));
}
}
@Override
public void meet(SqlConcat node) throws RuntimeException {
super.meet(node);
SqlExpr left = node.getLeftArg();
SqlExpr right = node.getRightArg();
if (left instanceof StringValue && right instanceof StringValue) {
StringValue l = (StringValue) left;
StringValue r = (StringValue) right;
replace(node, new StringValue(l.getValue() + r.getValue()));
}
}
@Override
public void meet(SqlOr node) throws RuntimeException {
super.meet(node);
SqlExpr left = node.getLeftArg();
SqlExpr right = node.getRightArg();
if (left instanceof TrueValue || right instanceof TrueValue) {
replace(node, new TrueValue());
} else if (left instanceof FalseValue && right instanceof FalseValue) {
replace(node, new FalseValue());
} else if (left instanceof FalseValue) {
replace(node, right.clone());
} else if (right instanceof FalseValue) {
replace(node, left.clone());
} else if (right instanceof SqlNull && andAllTheWay(node)) {
replace(node, left.clone());
} else if (left instanceof SqlNull && andAllTheWay(node)) {
replace(node, right.clone());
} else if (right instanceof SqlNull && left instanceof SqlNull) {
replace(node, new SqlNull());
} else if (left instanceof SqlNull && right instanceof SqlOr) {
SqlOr r = (SqlOr) right;
SqlExpr rleft = r.getLeftArg();
SqlExpr rright = r.getRightArg();
if (rleft instanceof SqlNull || rright instanceof SqlNull) {
replace(node, right.clone());
}
} else if (right instanceof SqlNull && left instanceof SqlOr) {
SqlOr l = (SqlOr) left;
SqlExpr lleft = l.getLeftArg();
SqlExpr lright = l.getRightArg();
if (lleft instanceof SqlNull || lright instanceof SqlNull) {
replace(node, left.clone());
}
} else if (right instanceof SqlNull && left instanceof SqlAnd) {
// value IS NOT NULL AND value = ? OR NULL
// -> value = ?
SqlAnd l = (SqlAnd) left;
SqlExpr lleft = l.getLeftArg();
SqlExpr lright = l.getRightArg();
SqlExpr isNotNull = arg(arg(lleft, SqlNot.class), SqlIsNull.class);
SqlExpr isNotEq = other(lright, isNotNull, SqlEq.class);
if (isNotEq instanceof SqlConstant) {
replace(node, lright);
}
}
}
@Override
public void meet(SqlEq node) throws RuntimeException {
super.meet(node);
SqlExpr left = node.getLeftArg();
SqlExpr right = node.getRightArg();
if (left instanceof SqlNull || right instanceof SqlNull) {
replace(node, new SqlNull());
} else if (left instanceof SqlConstant<?> && right instanceof SqlConstant<?>) {
SqlConstant<?> l = (SqlConstant<?>) left;
SqlConstant<?> r = (SqlConstant<?>) right;
if (l.getValue().equals(r.getValue())) {
replace(node, new TrueValue());
} else {
replace(node, new FalseValue());
}
}
}
@Override
public void meet(SqlNot node) throws RuntimeException {
super.meet(node);
SqlExpr arg = node.getArg();
if (arg instanceof TrueValue) {
replace(node, new FalseValue());
} else if (arg instanceof FalseValue) {
replace(node, new TrueValue());
} else if (arg instanceof SqlNull) {
replace(node, new SqlNull());
} else if (arg instanceof SqlNot) {
SqlNot not = (SqlNot) arg;
replace(node, not.getArg().clone());
} else if (arg instanceof SqlOr) {
SqlOr or = (SqlOr) arg;
replace(node, and(not(or.getLeftArg().clone()), not(or.getRightArg().clone())));
}
}
@Override
public void meet(SqlAnd node) throws RuntimeException {
super.meet(node);
SqlExpr left = node.getLeftArg();
SqlExpr right = node.getRightArg();
if (left instanceof FalseValue || right instanceof FalseValue) {
replace(node, new FalseValue());
} else if (left instanceof TrueValue && right instanceof TrueValue) {
replace(node, new TrueValue());
} else if (left instanceof TrueValue) {
replace(node, right.clone());
} else if (right instanceof TrueValue) {
replace(node, left.clone());
} else if (right instanceof SqlNull || left instanceof SqlNull) {
replace(node, new SqlNull());
} else if (right instanceof SqlNot && ((SqlNot) right).getArg().equals(left)) {
replace(node, new FalseValue());
} else if (left instanceof SqlNot && ((SqlNot) left).getArg().equals(right)) {
replace(node, new FalseValue());
}
}
@Override
public <X extends Exception> void visit(RdbmsQueryModelVisitorBase<X> visitor) throws X {
visitor.meet(this);
}
