protected Operation transform(DeleteOperation delA, DeleteOperation delB) {
int posA = delA.getPosition();
int lenA = delA.getTextLength();
int posB = delB.getPosition();
int lenB = delB.getTextLength();
if (posB >= (posA + lenA)) {
/*
* Operation A is completely before operation B.
*/
return delA;
} else if (posA >= (posB + lenB)) {
/*
* Operation A starts at the end or after operation B. Index of
* operation A' must be reduced by the length of the text of
* operation B.
*/
return new DeleteOperation(posA - lenB, delA.getText());
} else {
/*
* Operation A and operation B are overlapping.
*/
if ((posB <= posA) && ((posA + lenA) <= (posB + lenB))) {
/*
* Operation B starts before or at the same position like
* operation A and ends after or at the same position like
* operation A.
*/
return new NoOperation();
} else if ((posB <= posA) && ((posA + lenA) > (posB + lenB))) {
/*
* Operation B starts before or at the same position like
* operation A and ends before operation A.
*/
return new DeleteOperation(posB, delA.getText().substring(posB + lenB - posA, lenA));
} else if ((posB > posA) && ((posB + lenB) >= (posA + lenA))) {
/*
* Operation B starts after operation A and ends after or at the
* same position like operation A.
*/
return new DeleteOperation(posA, delA.getText().substring(0, posB - posA));
} else {
/*
* Operation B is fully in operation A.
*/
return new DeleteOperation(
posA,
delA.getText().substring(0, posB - posA)
+ delA.getText().substring(posB + lenB - posA, lenA));
}
}
}
protected Operation transform(DeleteOperation delA, InsertOperation insB) {
int posA = delA.getPosition();
int lenA = delA.getTextLength();
int posB = insB.getPosition();
int lenB = insB.getTextLength();
if (posB >= (posA + lenA)) {
/*
* Operation B is completely after operation A.
*/
return delA;
} else if (posB <= posA) {
/*
* Operation B starts before or at the same position like operation
* A
*/
return new DeleteOperation(posA + lenB, delA.getText());
} else {
/*
* Operation B (insert) is in the range of operation A (delete).
* Operation A' must be split up into two delete operations. (A):
* "123456" (A'): "1" "23456"
*/
DeleteOperation del1 = new DeleteOperation(posA, delA.getText().substring(0, posB - posA));
DeleteOperation del2 =
new DeleteOperation(posA + lenB, delA.getText().substring(posB - posA, lenA));
return new SplitOperation(del1, del2);
}
}
protected Operation transform(InsertOperation insA, DeleteOperation delB) {
int posA = insA.getPosition();
int posB = delB.getPosition();
int lenB = delB.getTextLength();
if (posA <= posB) {
/*
* Operation A starts before or at the same position like operation
*/
return insA;
} else if (posA > (posB + lenB)) {
/*
* Operation A starts after operation B. Index of operation A' must
* be reduced by the length of the text of operation B.
*/
return new InsertOperation(posA - lenB, insA.getText(), insA.getOrigin());
} else {
/*
* Operation A starts in operation B. Index of A' must be the index
* of operation B.
*/
return new InsertOperation(posB, insA.getText(), insA.getOrigin());
}
}
