ormbatchchange.h
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#ifndef OSDEV_COMPONENTS_ORMBATCHCHANGE_H
#define OSDEV_COMPONENTS_ORMBATCHCHANGE_H
#include <set>
#include <QVariant>
#include "timestamp.h"
namespace osdev {
namespace components {
/**
* @brief Describes a change that should happen or has happened on a BatchUpdate or MergeUpdate table.
*/
class OrmBatchChange
{
public:
/**
* @brief Creates an invalid OrmBatchChange.
* @note The only way to make an OrmBatchChange valid is by assigning a valid OrmBatchChange to it.
*/
OrmBatchChange();
/**
* @brief Create an OrmBatchChange with a change description.
* @param ts A valid timestamp (not checked).
* @param foreignId The value that should be pointed to.
* @param changeSet The set of record identifiers of records that should point to the given foreignId.
*/
OrmBatchChange(const Timestamp& ts, const QVariant& foreignId, const std::set<QVariant>& changeSet);
// Default copyable and movable.
OrmBatchChange(const OrmBatchChange&) = default;
OrmBatchChange& operator=(const OrmBatchChange&) = default;
OrmBatchChange(OrmBatchChange&&) = default;
OrmBatchChange& operator=(OrmBatchChange&&) = default;
/**
* @brief Process an already executed change on this change.
* The changeset of this object can be reshaped as a result.
* @param change A known change.
* @param exclusiveUpdate Flag that indicates if the change should be processed in an exclusive way.
* @return true to indicate this change is still valid and false otherwise.
* @note An exclusiveUpdate means that all records that are not mentioned in the change set will not point to the given foreignId.
*/
bool processChange(const OrmBatchChange& change, bool exclusiveUpdate);
/**
* @brief Changes are ordered w.r.t. each other by their timestamp.
*/
bool operator<(const OrmBatchChange& rhs) const
{
return m_changeTimestamp < rhs.m_changeTimestamp;
}
/**
* @brief Change the timestamp of this change.
* This is necessary when the change is recorded to be permanent. It then becomes the latest change.
* @param ts The new timestamp (no checks).
*/
void setTimestamp(const Timestamp& ts)
{
m_changeTimestamp = ts;
}
/**
* @return The timestamp of this change.
*/
const Timestamp& timestamp() const
{
return m_changeTimestamp;
}
/**
* @return The foreinId of this change.
*/
QVariant foreignId() const
{
return m_foreignId;
}
/**
* @return The change set of this change.
*/
std::set<QVariant> changeSet() const
{
return m_changeSet;
}
/**
* @return true if this change is valid, false otherwise.
*/
bool valid() const
{
return m_valid;
}
/**
* @brief Static method to convert a QList<QVariant> to an std::set<QVariant>.
* @param lst The QList<QVariant> to convert.
* @return the converted set.
*/
static std::set<QVariant> toSet(const QList<QVariant>& lst);
/**
* @brief Static method to convert an std::set<QVariant> to a QList<QVariant>.
* @param variantSet The set of variants to convert.
* @return the converted QList.
*/
static QList<QVariant> toList(const std::set<QVariant>& variantSet);
private:
Timestamp m_changeTimestamp; ///< The timestamp of this change.
QVariant m_foreignId; ///< The foreignId that should be pointed to.
std::set<QVariant> m_changeSet; ///< The set of record identifiers that describe the change.
bool m_valid; ///< Flag that indicates if this change is valid.
};
} /* End namespace components */
} /* End namespace osdev */
#endif /* OSDEV_COMPONENTS_ORMBATCHCHANGE_H */