Exception while sorting a list of objects based on date property(String type)
I am trying to sort a list of Objects based on dates (In String). The dates are in string and the objects have date property value assigned "-" if there is no date with it.
I am doing the below code snippet to sort it however at one point it is giving me " Comparison method violates its general contract" exception. I am not able to figure out where the contract is breaking and how.
I looked into other threads but could not get much help.
Any inputs what could I be doing wrong?
Collections.sort(listOfObjects, new Comparator<ObjectType>(){
@Override
public int compare(ObjectType objectOne, ObjectType objectTwo) {
if(sortType.equalsIgnoreCase("asc")){
if(objectOne.getSomeDate().equalsIgnoreCase("-"))
return 1;
if(objectTwo.getDeliveryQueueResponseDTO().getSomeDate().equalsIgnoreCase("-"))
return -1;
sort = objectOne.getSomeDate().compareToIgnoreCase(objectTwo.getSomeDate());
}
else
sort = objectTwo.getSomeDate().compareToIgnoreCase(objectOne.getSomeDate());
}
return sort;
}
java collections comparator
asked Nov 15 '18 at 17:29
user3262365user3262365
248
add a comment |
I am trying to sort a list of Objects based on dates (In String). The dates are in string and the objects have date property value assigned "-" if there is no date with it.
I am doing the below code snippet to sort it however at one point it is giving me " Comparison method violates its general contract" exception. I am not able to figure out where the contract is breaking and how.
I looked into other threads but could not get much help.
Any inputs what could I be doing wrong?
Collections.sort(listOfObjects, new Comparator<ObjectType>(){
@Override
public int compare(ObjectType objectOne, ObjectType objectTwo) {
if(sortType.equalsIgnoreCase("asc")){
if(objectOne.getSomeDate().equalsIgnoreCase("-"))
return 1;
if(objectTwo.getDeliveryQueueResponseDTO().getSomeDate().equalsIgnoreCase("-"))
return -1;
sort = objectOne.getSomeDate().compareToIgnoreCase(objectTwo.getSomeDate());
}
else
sort = objectTwo.getSomeDate().compareToIgnoreCase(objectOne.getSomeDate());
}
return sort;
}
java collections comparator
asked Nov 15 '18 at 17:29
user3262365user3262365
248
add a comment |
I am trying to sort a list of Objects based on dates (In String). The dates are in string and the objects have date property value assigned "-" if there is no date with it.
I am doing the below code snippet to sort it however at one point it is giving me " Comparison method violates its general contract" exception. I am not able to figure out where the contract is breaking and how.
I looked into other threads but could not get much help.
Any inputs what could I be doing wrong?
Collections.sort(listOfObjects, new Comparator<ObjectType>(){
@Override
public int compare(ObjectType objectOne, ObjectType objectTwo) {
if(sortType.equalsIgnoreCase("asc")){
if(objectOne.getSomeDate().equalsIgnoreCase("-"))
return 1;
if(objectTwo.getDeliveryQueueResponseDTO().getSomeDate().equalsIgnoreCase("-"))
return -1;
sort = objectOne.getSomeDate().compareToIgnoreCase(objectTwo.getSomeDate());
}
else
sort = objectTwo.getSomeDate().compareToIgnoreCase(objectOne.getSomeDate());
}
return sort;
}
java collections comparator
asked Nov 15 '18 at 17:29
user3262365user3262365
248
I am trying to sort a list of Objects based on dates (In String). The dates are in string and the objects have date property value assigned "-" if there is no date with it.
I am doing the below code snippet to sort it however at one point it is giving me " Comparison method violates its general contract" exception. I am not able to figure out where the contract is breaking and how.
I looked into other threads but could not get much help.
Any inputs what could I be doing wrong?
Collections.sort(listOfObjects, new Comparator<ObjectType>(){
@Override
public int compare(ObjectType objectOne, ObjectType objectTwo) {
if(sortType.equalsIgnoreCase("asc")){
if(objectOne.getSomeDate().equalsIgnoreCase("-"))
return 1;
if(objectTwo.getDeliveryQueueResponseDTO().getSomeDate().equalsIgnoreCase("-"))
return -1;
sort = objectOne.getSomeDate().compareToIgnoreCase(objectTwo.getSomeDate());
}
else
sort = objectTwo.getSomeDate().compareToIgnoreCase(objectOne.getSomeDate());
}
return sort;
}
java collections comparator
java collections comparator
asked Nov 15 '18 at 17:29
user3262365user3262365
248
asked Nov 15 '18 at 17:29
user3262365user3262365
248
asked Nov 15 '18 at 17:29
user3262365user3262365
248
asked Nov 15 '18 at 17:29
user3262365user3262365
248
asked Nov 15 '18 at 17:29
user3262365user3262365
248
248
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
You should implement correctly the comparison between to "-" (empty dates).
If you don't you get that a="-" and b="-" you have that compare(a,b)==1 and compare(b,a)==1 so a>b and b>a which don't make sense.
answered Nov 15 '18 at 17:40
minusminus
1,8411113
I figured it out. Thanks buddy.
– user3262365
Nov 15 '18 at 17:56
add a comment |
It basically means your comparator is not transitive. For more details, look at this question:
"Comparison method violates its general contract!"
answered Nov 15 '18 at 17:35
mjuarezmjuarez
10.2k73954
Can you point out in my code where it is not transitive?
– user3262365
Nov 15 '18 at 17:36
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
You should implement correctly the comparison between to "-" (empty dates).
If you don't you get that a="-" and b="-" you have that compare(a,b)==1 and compare(b,a)==1 so a>b and b>a which don't make sense.
answered Nov 15 '18 at 17:40
minusminus
1,8411113
I figured it out. Thanks buddy.
– user3262365
Nov 15 '18 at 17:56
add a comment |
You should implement correctly the comparison between to "-" (empty dates).
If you don't you get that a="-" and b="-" you have that compare(a,b)==1 and compare(b,a)==1 so a>b and b>a which don't make sense.
answered Nov 15 '18 at 17:40
minusminus
1,8411113
I figured it out. Thanks buddy.
– user3262365
Nov 15 '18 at 17:56
add a comment |
You should implement correctly the comparison between to "-" (empty dates).
If you don't you get that a="-" and b="-" you have that compare(a,b)==1 and compare(b,a)==1 so a>b and b>a which don't make sense.
answered Nov 15 '18 at 17:40
minusminus
1,8411113
You should implement correctly the comparison between to "-" (empty dates).
If you don't you get that a="-" and b="-" you have that compare(a,b)==1 and compare(b,a)==1 so a>b and b>a which don't make sense.
answered Nov 15 '18 at 17:40
minusminus
1,8411113
answered Nov 15 '18 at 17:40
minusminus
1,8411113
answered Nov 15 '18 at 17:40
minusminus
1,8411113
answered Nov 15 '18 at 17:40
minusminus
1,8411113
1,8411113
I figured it out. Thanks buddy.
– user3262365
Nov 15 '18 at 17:56
add a comment |
I figured it out. Thanks buddy.
– user3262365
Nov 15 '18 at 17:56
I figured it out. Thanks buddy.
– user3262365
Nov 15 '18 at 17:56
I figured it out. Thanks buddy.
– user3262365
Nov 15 '18 at 17:56
add a comment |
It basically means your comparator is not transitive. For more details, look at this question:
"Comparison method violates its general contract!"
answered Nov 15 '18 at 17:35
mjuarezmjuarez
10.2k73954
Can you point out in my code where it is not transitive?
– user3262365
Nov 15 '18 at 17:36
add a comment |
It basically means your comparator is not transitive. For more details, look at this question:
"Comparison method violates its general contract!"
answered Nov 15 '18 at 17:35
mjuarezmjuarez
10.2k73954
Can you point out in my code where it is not transitive?
– user3262365
Nov 15 '18 at 17:36
add a comment |
It basically means your comparator is not transitive. For more details, look at this question:
"Comparison method violates its general contract!"
answered Nov 15 '18 at 17:35
mjuarezmjuarez
10.2k73954
It basically means your comparator is not transitive. For more details, look at this question:
"Comparison method violates its general contract!"
answered Nov 15 '18 at 17:35
mjuarezmjuarez
10.2k73954
answered Nov 15 '18 at 17:35
mjuarezmjuarez
10.2k73954
answered Nov 15 '18 at 17:35
mjuarezmjuarez
10.2k73954
answered Nov 15 '18 at 17:35
mjuarezmjuarez
10.2k73954
10.2k73954
Can you point out in my code where it is not transitive?
– user3262365
Nov 15 '18 at 17:36
add a comment |
Can you point out in my code where it is not transitive?
– user3262365
Nov 15 '18 at 17:36
Can you point out in my code where it is not transitive?
– user3262365
Nov 15 '18 at 17:36
Can you point out in my code where it is not transitive?
– user3262365
Nov 15 '18 at 17:36
add a comment |
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