public SqlRexConvertlet get(SqlCall call) {
SqlRexConvertlet convertlet;
final SqlOperator op = call.getOperator();
// Is there a convertlet for this operator
// (e.g. SqlStdOperatorTable.plusOperator)?
convertlet = (SqlRexConvertlet) map.get(op);
if (convertlet != null) {
return convertlet;
}
// Is there a convertlet for this class of operator
// (e.g. SqlBinaryOperator)?
Class<? extends Object> clazz = op.getClass();
while (clazz != null) {
convertlet = (SqlRexConvertlet) map.get(clazz);
if (convertlet != null) {
return convertlet;
}
clazz = clazz.getSuperclass();
}
// Is there a convertlet for this class of expression
// (e.g. SqlCall)?
clazz = call.getClass();
while (clazz != null) {
convertlet = (SqlRexConvertlet) map.get(clazz);
if (convertlet != null) {
return convertlet;
}
clazz = clazz.getSuperclass();
}
return null;
}
public <T> T unwrap(Class<T> clazz) {
if (clazz.isInstance(this)) {
return clazz.cast(this);
}
return parent.unwrap(clazz);
}