132 lines
4.5 KiB
C++
132 lines
4.5 KiB
C++
|
#ifndef SECONDO_RECORD_ADAPTER_H
|
||
|
|
#define SECONDO_RECORD_ADAPTER_H
|
||
|
|
|
||
|
|
#include "Algebras/DBService2/DatabaseAdapter.hpp"
|
||
|
|
|
||
|
|
#include "NestedList.h"
|
||
|
|
|
||
|
|
extern NestedList* nl;
|
||
|
|
extern boost::recursive_mutex nlparsemtx;
|
||
|
|
|
||
|
|
#include <loguru.hpp>
|
||
|
|
|
||
|
|
namespace DBService
|
||
|
|
{
|
||
|
|
|
||
|
|
template<typename RecordType, typename RecordAdapterType>
|
||
|
|
class Record;
|
||
|
|
|
||
|
|
/*
|
||
|
|
|
||
|
|
Similar to the type mapping of Secondo Algebra modules, within the ORM
|
||
|
|
there is a need to map objects represented as nested list into
|
||
|
|
data structures. In the ORM these data structures are substypes of the
|
||
|
|
Record class.
|
||
|
|
|
||
|
|
In order to achieve the transformation of the nested listed list
|
||
|
|
representation into the Record subclass the Adapter Pattern is used.
|
||
|
|
See: https://refactoring.guru/design-patterns/adapter/cpp/example
|
||
|
|
|
||
|
|
The Adapter implictly acts as a factory method
|
||
|
|
(https://refactoring.guru/design-patterns/factory-method) to construct
|
||
|
|
Record objects such as Nodes, Relations, etc.
|
||
|
|
|
||
|
|
|
||
|
|
Template classes do not have a cpp file as their definition needs
|
||
|
|
to be done inside the header file.
|
||
|
|
See: https://bit.ly/3fKw1IS
|
||
|
|
*/
|
||
|
|
template <class RecordType, class RecordAdapterType>
|
||
|
|
class SecondoRecordAdapter {
|
||
|
|
public:
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
Builds a vector of shared_ptr T (Nodes) from a resultList obtained
|
||
|
|
e.g. by executing a find statement.
|
||
|
|
|
||
|
|
The resultListOffset sets the offset from which relevant records
|
||
|
|
within the nested list are to be expected.
|
||
|
|
It is assumed that relevent entries are contained in the NL in a
|
||
|
|
particular attribute order.
|
||
|
|
*/
|
||
|
|
static std::vector<std::shared_ptr<RecordType> >
|
||
|
|
buildVectorFromNestedList(
|
||
|
|
std::string database, std::shared_ptr<DatabaseAdapter> dbAdapter,
|
||
|
|
ListExpr resultList, int resultListOffset = 0) {
|
||
|
|
|
||
|
|
std::vector<std::shared_ptr<RecordType> > records;
|
||
|
|
|
||
|
|
/* The resultList contains a header which we are not interested in.
|
||
|
|
* Example:
|
||
|
|
* (
|
||
|
|
* (rel (tuple ((Host text) (Port int) (Config text) (DiskPath text)
|
||
|
|
* (ComPort int) (TransferPort int) (TID tid))))
|
||
|
|
* (
|
||
|
|
* ('localhost' 1245 '' '/home/doesnt_exist/secondo' 9941 9942 1)
|
||
|
|
* ('localhost' 1245 '' '/home/doesnt_exist/secondo' 9941 9942 2)
|
||
|
|
* ('localhost' 1245 '' '/home/doesnt_exist/secondo' 9941 9942 3)
|
||
|
|
* ('localhost' 1245 '' '/home/doesnt_exist/secondo' 9941 9942 4)
|
||
|
|
* )
|
||
|
|
* )
|
||
|
|
*
|
||
|
|
* The list of records is the 2nd element
|
||
|
|
*/
|
||
|
|
|
||
|
|
LOG_F(INFO, "%s", "Acquiring lock for nlparsemtx...");
|
||
|
|
boost::unique_lock<boost::recursive_mutex> nlLock(nlparsemtx);
|
||
|
|
LOG_F(INFO, "%s", "Successfully acquired lock for nlparsemtx...");
|
||
|
|
|
||
|
|
ListExpr recordList = nl->Second(resultList);
|
||
|
|
|
||
|
|
while ( !nl->IsEmpty(recordList) ) {
|
||
|
|
|
||
|
|
// Obtain a record from the list of records.
|
||
|
|
// ('localhost' 1245 '' '/home/doesnt_exist/secondo' 9941 9942 1)
|
||
|
|
ListExpr currentRecordNL = nl->First(recordList);
|
||
|
|
|
||
|
|
std::shared_ptr<RecordType> currentRecord =
|
||
|
|
buildObjectFromNestedList(database, currentRecordNL,
|
||
|
|
resultListOffset);
|
||
|
|
|
||
|
|
currentRecord->setDatabase(database);
|
||
|
|
currentRecord->setDatabaseAdapter(dbAdapter);
|
||
|
|
|
||
|
|
records.push_back(currentRecord);
|
||
|
|
|
||
|
|
// Set the recordList to the reduced List without the currentRow
|
||
|
|
recordList = nl->Rest(recordList);
|
||
|
|
}
|
||
|
|
|
||
|
|
return records;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
Factory method constructing Record substypes from a given nested list
|
||
|
|
acting as an Adapter.
|
||
|
|
|
||
|
|
Input is a nested list.
|
||
|
|
Returns a newly constructed Record object of the Type T (e.g. Node).
|
||
|
|
*/
|
||
|
|
static std::shared_ptr<RecordType> buildObjectFromNestedList(
|
||
|
|
std::string database, ListExpr recordAsNestedList,
|
||
|
|
int resultListOffset = 0) {
|
||
|
|
|
||
|
|
/*
|
||
|
|
The static_cast makes the buildObjectFromNestedList implementation
|
||
|
|
"pluggable". When configuring specific SecondoRecordAdapter, e.g.
|
||
|
|
the SecondoRelationAdapter the SecondoRelationAdapter can inherit
|
||
|
|
from the SecondoRecordAdapter and override the buildObjectFromNestedList
|
||
|
|
function.
|
||
|
|
|
||
|
|
See: https://www.youtube.com/watch?v=-WV9vWjhI3g&ab_channel=BoQian
|
||
|
|
*/
|
||
|
|
|
||
|
|
return RecordAdapterType::buildObjectFromNestedList(
|
||
|
|
database, recordAsNestedList, resultListOffset);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace DBService
|
||
|
|
|
||
|
|
#endif
|