Ví dụ dưới đây bao gồm 3 giao dịch lồng nhau. Chuỗi sự kiện như sau:
Để tạo một giao dịch lồng mới
- Tạo một đa giác mới và đưa nó vào trong Cơ sở dữ liệu.
- Bắt đầu giao dịch 1:
- Lựa chọn đa giác và lấy con trỏ tới nó. Mở để đọc.
- Tạo một khối đặc (extruded solid) từ đa giác.
- Tạo một khối trụ ở giữa đa giác mở rộng.
- Bắt đầu giao dịch 2: Trừ khối trụ từ khối đặc (Tạo một lỗ hổng ở giữa khối đặc).
- Bắt đầu giao dịch 3:
- Cắt một nửa khuôn mẫu dọc theo mặt phẳng X/Z và di chuyển nó quanh trục X để bạn có thể nhìn thấy hai mảnh.
- Hủy bỏ giao dịch được không nhỉ? Câu trả lời là có.
- Bắt đầu giao dịch 3 (bắt đầu lai): Cắt khuôn mẫu dọc theo mặt phẳng Y/Z và di chuyển nó quanh trục Y.
- Kết thúc giao dịch 3.
- Kết thúc giao dịch 2.
Chú ý: Nếu bạn muốn hủy bỏ tại điểm này, Giao dịch 2 và 3 cũng bị hủy đồng thời. Nếu bạn hủy bỏ một giao dịch vòng ngoài, mọi giao dịch lồng bên trong cũng bị hủy theo, thậm chí nếu chúng đã kết thúc thành công trước đó.
- Kết thúc giao dịch 1.
Dưới đây là mã nguồn của ví dụ:
void
transactCommand()
{
Adesk::Boolean interrupted;
Acad::ErrorStatus es = Acad::eOk;
AcDbObjectId savedCylinderId,savedExtrusionId;
// Create a poly and post it to the database.
//
acutPrintf("\nCreating a poly...Please supply the"
" required input.");
if ((es = createAndPostPoly()) != Acad::eOk)
return;
// Start a transaction.
//
AcTransaction *pTrans
= actrTransactionManager->startTransaction();
assert(pTrans != NULL);
acutPrintf("\n\n###### Started transaction one."
" ######\n");
// Select the poly and extrude it.
//
AcDbObject *pObj = NULL;
AsdkPoly *pPoly = NULL;
AcDb3dSolid *pSolid = NULL;
AcDbObjectId objId;
ads_name ename;
ads_point pickpt;
for (;;) {
switch (acedEntSel("\nSelect a polygon: ",
ename, pickpt))
{
case RTNORM:
acdbGetObjectId(objId, ename);
if ((es = pTrans->getObject(pObj, objId,
AcDb::kForRead)) != Acad::eOk)
{
acutPrintf("\nFailed to obtain an object"
" through transaction.");
actrTransactionManager->abortTransaction();
return;
}
assert(pObj != NULL);
pPoly = AsdkPoly::cast(pObj);
if (pPoly == NULL) {
acutPrintf("\nNot a polygon. Try again");
continue;
}
break;
case RTNONE:
case RTCAN:
actrTransactionManager->abortTransaction();
return;
default:
continue;
}
break;
}
// Now that a poly is created, convert it to a region
// and extrude it.
//
acutPrintf("\nWe will be extruding the poly.");
AcGePoint2d c2d = pPoly->center();
ads_point pt;
pt[0] = c2d[0]; pt[1] = c2d[1]; pt[2] = pPoly->elevation();
acdbEcs2Ucs(pt,pt,asDblArray(pPoly->normal()),Adesk::kFalse);
double height;
if (acedGetDist(pt, "\nEnter Extrusion height: ",
&height) != RTNORM)
{
actrTransactionManager->abortTransaction();
return;
}
if ((es = extrudePoly(pPoly, height,savedExtrusionId)) !=
Acad::eOk) {
actrTransactionManager->abortTransaction();
return;
}
// Create a cylinder at the center of the polygon of
// the same height as the extruded poly.
//
double radius = (pPoly->startPoint()
- pPoly->center()).length() * 0.5;
pSolid = new AcDb3dSolid;
assert(pSolid != NULL);
pSolid->createFrustum(height, radius, radius, radius);
AcGeMatrix3d mat(AcGeMatrix3d::translation(
pPoly->elevation()*pPoly->normal())*
AcGeMatrix3d::planeToWorld(pPoly->normal()));
pSolid->transformBy(mat);
// Move it up again by half the height along
// the normal.
//
AcGeVector3d x(1, 0, 0), y(0, 1, 0), z(0, 0, 1);
AcGePoint3d moveBy(pPoly->normal()[0] * height * 0.5,
pPoly->normal()[1] * height * 0.5,
pPoly->normal()[2] * height * 0.5);
mat.setCoordSystem(moveBy, x, y, z);
pSolid->transformBy(mat);
addToDb(pSolid, savedCylinderId);
actrTransactionManager
->addNewlyCreatedDBRObject(pSolid);
pSolid->draw();
acutPrintf("\nCreated a cylinder at the center of"
" the poly.");
// Start another transaction. Ask the user to select
// the extruded solid followed by selecting the
// cylinder. Make a hole in the extruded solid by
// subtracting the cylinder from it.
//
pTrans = actrTransactionManager->startTransaction();
assert(pTrans != NULL);
acutPrintf("\n\n###### Started transaction two."
" ######\n");
AcDb3dSolid *pExtrusion, *pCylinder;
if ((es = getASolid("\nSelect the extrusion: ", pTrans,
AcDb::kForWrite, savedExtrusionId, pExtrusion))
!= Acad::eOk)
{
actrTransactionManager->abortTransaction();
actrTransactionManager->abortTransaction();
return;
}
assert(pExtrusion != NULL);
if ((es = getASolid("\nSelect the cylinder: ", pTrans,
AcDb::kForWrite, savedCylinderId, pCylinder))
!= Acad::eOk)
{
actrTransactionManager->abortTransaction();
actrTransactionManager->abortTransaction();
return;
}
assert(pCylinder != NULL);
pExtrusion->booleanOper(AcDb::kBoolSubtract, pCylinder);
pExtrusion->draw();
acutPrintf("\nSubtracted the cylinder from the"
" extrusion.");
// At this point, the cylinder is a NULL solid. Erase it.
//
assert(pCylinder->isNull());
pCylinder->erase();
// Start another transaction and slice the resulting
// solid into two halves.
//
pTrans = actrTransactionManager->startTransaction();
assert(pTrans != NULL);
acutPrintf("\n\n##### Started transaction three."
" ######\n");
AcGeVector3d vec, normal;
AcGePoint3d sp,center;
pPoly->getStartPoint(sp);
pPoly->getCenter(center);
vec = sp - center;
normal = pPoly->normal().crossProduct(vec);
normal.normalize();
AcGePlane sectionPlane(center, normal);
AcDb3dSolid *pOtherHalf = NULL;
pExtrusion->getSlice(sectionPlane, Adesk::kTrue,
pOtherHalf);
assert(pOtherHalf != NULL);
// Move the other half three times the vector length
// along the vector.
//
moveBy.set(vec[0] * 3.0, vec[1] * 3.0, vec[2] * 3.0);
mat.setCoordSystem(moveBy, x, y, z);
pOtherHalf->transformBy(mat);
AcDbObjectId otherHalfId;
addToDb(pOtherHalf, otherHalfId);
actrTransactionManager
->addNewlyCreatedDBRObject(pOtherHalf);
pOtherHalf->draw();
pExtrusion->draw();
acutPrintf("\nSliced the resulting solid into half"
" and moved one piece.");
// Now abort transaction three, to return to the hole in
// the extrusion.
//
Adesk::Boolean yes = Adesk::kTrue;
if (getYOrN("\nLet's abort transaction three, yes?"
" [Y] : ", Adesk::kTrue, yes,interrupted) == Acad::eOk
&& yes == Adesk::kTrue)
{
acutPrintf("\n\n$$$$$$ Aborting transaction"
" three. $$$$$$\n");
actrTransactionManager->abortTransaction();
acutPrintf("\nBack to the un-sliced solid.");
pExtrusion->draw();
char option[256];
acedGetKword("\nHit any key to continue.", option);
} else {
acutPrintf("\n\n>>>>>> Ending transaction three."
" <<<<<<\n");
actrTransactionManager->endTransaction();
}
// Start another transaction (three again). This time,
// slice the solid along a plane that is perpendicular
// to the plane we used last time: that is the slice
// we really wanted.
//
pTrans = actrTransactionManager->startTransaction();
assert(pTrans != NULL);
acutPrintf("\n\n##### Started transaction three."
" ######\n");
moveBy.set(normal[0] * 3.0, normal[1] * 3.0,
normal[2] * 3.0);
normal = vec;
normal.normalize();
sectionPlane.set(center, normal);
pOtherHalf = NULL;
pExtrusion->getSlice(sectionPlane, Adesk::kTrue,
pOtherHalf);
assert(pOtherHalf != NULL);
mat.setCoordSystem(moveBy, x, y, z);
pOtherHalf->transformBy(mat);
addToDb(pOtherHalf, otherHalfId);
actrTransactionManager
->addNewlyCreatedDBRObject(pOtherHalf);
pOtherHalf->draw();
pExtrusion->draw();
acutPrintf("\nSliced the resulting solid into half"
" along a plane");
acutPrintf("\nperpendicular to the old one and moved"
" one piece.");
// Now, give the user the option to end all the transactions.
//
yes = Adesk::kFalse;
if (getYOrN("\nAbort transaction three?: ",
Adesk::kFalse, yes,interrupted) == Acad::eOk
&& yes == Adesk::kTrue)
{
acutPrintf("\n\n$$$$$$ Aborting transaction"
" three. $$$$$$\n");
actrTransactionManager->abortTransaction();
acutPrintf("\nBack to the un-sliced solid.");
} else {
acutPrintf("\n\n>>>>>> Ending transaction three."
" <<<<<<\n");
actrTransactionManager->endTransaction();
}
yes = Adesk::kFalse;
if (getYOrN("\nAbort transaction two?: ",
Adesk::kFalse, yes,interrupted) == Acad::eOk
&& yes == Adesk::kTrue)
{
acutPrintf("\n\n$$$$$$ Aborting transaction two."
" $$$$$$\n");
actrTransactionManager->abortTransaction();
acutPrintf("\nBack to separate extrusion and"
" cylinder.");
} else {
acutPrintf("\n\n>>>>>> Ending transaction two."
" <<<<<<\n");
actrTransactionManager->endTransaction();
}
yes = Adesk::kFalse;
if (getYOrN("\nAbort transaction one?: ",
Adesk::kFalse, yes,interrupted) == Acad::eOk
&& yes == Adesk::kTrue)
{
acutPrintf("\n\n$$$$$$ Aborting transaction one."
" $$$$$$\n");
actrTransactionManager->abortTransaction();
acutPrintf("\nBack to just the Poly.");
} else {
actrTransactionManager->endTransaction();
acutPrintf("\n\n>>>>>> Ending transaction one."
" <<<<<<\n");
}
}
static Acad::ErrorStatus
createAndPostPoly()
{
int nSides = 0;
while (nSides < 3) {
acedInitGet(INP_NNEG, "");
switch (acedGetInt("\nEnter number of sides: ",
&nSides))
{
case RTNORM:
if (nSides < 3)
acutPrintf("\nNeed at least 3 sides.");
break;
default:
return Acad::eInvalidInput;
}
}
ads_point center, startPt, normal;
if (acedGetPoint(NULL, "\nLocate center of polygon: ",
center) != RTNORM)
{
return Acad::eInvalidInput;
}
startPt[0] = center[0];
startPt[1] = center[1];
startPt[2] = center[2];
while (asPnt3d(startPt) == asPnt3d(center)) {
switch (acedGetPoint(center,
"\nLocate start point of polygon: ", startPt)) {
case RTNORM:
if (asPnt3d(center) == asPnt3d(startPt))
acutPrintf("\nPick a point different"
" from the center.");
break;
default:
return Acad::eInvalidInput;
}
}
// Set the normal to the plane of the polygon to be
// the same as the Z direction of the current UCS,
// (0, 0, 1) since we also got the center and
// start point in the current UCS. (acedGetPoint()
// returns in the current UCS.)
normal[X] = 0.0;
normal[Y] = 0.0;
normal[Z] = 1.0;
acdbUcs2Wcs(normal, normal, Adesk::kTrue);
acdbUcs2Ecs(center, center, normal, Adesk::kFalse);
acdbUcs2Ecs(startPt, startPt, normal, Adesk::kFalse);
double elev = center[2];
AcGePoint2d cen = asPnt2d(center),
start = asPnt2d(startPt);
AcGeVector3d norm = asVec3d(normal);
AsdkPoly *pPoly = new AsdkPoly;
if (pPoly==NULL)
return Acad::eOutOfMemory;
Acad::ErrorStatus es;
if ((es=pPoly->set(cen, start, nSides, norm,
"transactPoly",elev))!=Acad::eOk)
return es;
pPoly->setDatabaseDefaults(
acdbHostApplicationServices()->workingDatabase());
postToDb(pPoly);
return Acad::eOk;
}
// Extrudes the poly to a given height.
//
static Acad::ErrorStatus
extrudePoly(AsdkPoly* pPoly, double height, AcDbObjectId& savedExtrusionId)
{
Acad::ErrorStatus es = Acad::eOk;
// Explode to a set of lines.
//
AcDbVoidPtrArray lines;
pPoly->explode(lines);
// Create a region from the set of lines.
//
AcDbVoidPtrArray regions;
AcDbRegion::createFromCurves(lines, regions);
assert(regions.length() == 1);
AcDbRegion *pRegion
= AcDbRegion::cast((AcRxObject*)regions[0]);
assert(pRegion != NULL);
// Extrude the region to create a solid.
//
AcDb3dSolid *pSolid = new AcDb3dSolid;
assert(pSolid != NULL);
pSolid->extrude(pRegion, height, 0.0);
for (int i = 0; i < lines.length(); i++) {
delete (AcRxObject*)lines[i];
}
for (i = 0; i < regions.length(); i++) {
delete (AcRxObject*)regions[i];
}
// Now we have a solid. Add it to database, then
// associate the solid with a transaction. After
// this, transaction management is in charge of
// maintaining it.
//
pSolid->setPropertiesFrom(pPoly);
addToDb(pSolid, savedExtrusionId);
actrTransactionManager
->addNewlyCreatedDBRObject(pSolid);
pSolid->draw();
return Acad::eOk;
}
static Acad::ErrorStatus
getASolid(char* prompt,
AcTransaction* pTransaction,
AcDb::OpenMode mode,
AcDbObjectId checkWithThisId,
AcDb3dSolid*& pSolid)
{
AcDbObject *pObj = NULL;
AcDbObjectId objId;
ads_name ename;
ads_point pickpt;
for (;;) {
switch (acedEntSel(prompt, ename, pickpt)) {
case RTNORM:
AOK(acdbGetObjectId(objId, ename));
if (objId != checkWithThisId) {
acutPrintf("\n Select the proper"
" solid.");
continue;
}
AOK(pTransaction->getObject(pObj, objId, mode));
assert(pObj != NULL);
pSolid = AcDb3dSolid::cast(pObj);
if (pSolid == NULL) {
acutPrintf("\nNot a solid. Try again");
AOK(pObj->close());
continue;
}
break;
case RTNONE:
case RTCAN:
return Acad::eInvalidInput;
default:
continue;
}
break;
}
return Acad::eOk;
}
