Mixing
Optional cannot be converted to Int (for use on GUI Progress Bar)
I am receiving below error, when I try to set value on a JProgressBar.
"Optional cannot be converted to Int"
Could someone please advise any workarounds/Solution??
public GUI(){
initComponents();
tL = new TasksToDo();
jProgressBar1.setValue(tL.retrieveTotalHours());// [Where my error occurs]}
}
And from the TaskToDo Class, Originally I set this to ArrayList but the warnings said needed to switch to Optional:
public class TasksToDo {
public static ArrayList<Task> taskList;
public TasksToDo(){
taskList = new ArrayList<Task>();
taskList.add(new Task(0,"Whitepaper", "Write first draft of Whitepaper", 7));
taskList.add(new Task(1,"Create Database Structure", "Plan required fields and tables", 1));
taskList.add(new Task(2,"Setup ODBC Connections", "Create the ODBC Connections between SVR1 to DEV-SVR", 2));
}
public void addTask (int taskId, String taskTitle, String taskDescription, int taskHours){}
public ArrayList<Task> retrieveTask(){
return taskList;
}
public Optional<Integer> retrieveTotalHours(){
return taskList.stream().map(e -> e.getTaskHours()).reduce(Integer::sum);
}
}
java netbeans stream optional jprogressbar
edited Nov 21 '18 at 10:53
Suryavel TR
2,46311420
asked Nov 21 '18 at 9:16
craig157craig157
155
add a comment |
I am receiving below error, when I try to set value on a JProgressBar.
"Optional cannot be converted to Int"
Could someone please advise any workarounds/Solution??
public GUI(){
initComponents();
tL = new TasksToDo();
jProgressBar1.setValue(tL.retrieveTotalHours());// [Where my error occurs]}
}
And from the TaskToDo Class, Originally I set this to ArrayList but the warnings said needed to switch to Optional:
public class TasksToDo {
public static ArrayList<Task> taskList;
public TasksToDo(){
taskList = new ArrayList<Task>();
taskList.add(new Task(0,"Whitepaper", "Write first draft of Whitepaper", 7));
taskList.add(new Task(1,"Create Database Structure", "Plan required fields and tables", 1));
taskList.add(new Task(2,"Setup ODBC Connections", "Create the ODBC Connections between SVR1 to DEV-SVR", 2));
}
public void addTask (int taskId, String taskTitle, String taskDescription, int taskHours){}
public ArrayList<Task> retrieveTask(){
return taskList;
}
public Optional<Integer> retrieveTotalHours(){
return taskList.stream().map(e -> e.getTaskHours()).reduce(Integer::sum);
}
}
java netbeans stream optional jprogressbar
edited Nov 21 '18 at 10:53
Suryavel TR
2,46311420
asked Nov 21 '18 at 9:16
craig157craig157
155
add a comment |
I am receiving below error, when I try to set value on a JProgressBar.
"Optional cannot be converted to Int"
Could someone please advise any workarounds/Solution??
public GUI(){
initComponents();
tL = new TasksToDo();
jProgressBar1.setValue(tL.retrieveTotalHours());// [Where my error occurs]}
}
And from the TaskToDo Class, Originally I set this to ArrayList but the warnings said needed to switch to Optional:
public class TasksToDo {
public static ArrayList<Task> taskList;
public TasksToDo(){
taskList = new ArrayList<Task>();
taskList.add(new Task(0,"Whitepaper", "Write first draft of Whitepaper", 7));
taskList.add(new Task(1,"Create Database Structure", "Plan required fields and tables", 1));
taskList.add(new Task(2,"Setup ODBC Connections", "Create the ODBC Connections between SVR1 to DEV-SVR", 2));
}
public void addTask (int taskId, String taskTitle, String taskDescription, int taskHours){}
public ArrayList<Task> retrieveTask(){
return taskList;
}
public Optional<Integer> retrieveTotalHours(){
return taskList.stream().map(e -> e.getTaskHours()).reduce(Integer::sum);
}
}
java netbeans stream optional jprogressbar
edited Nov 21 '18 at 10:53
Suryavel TR
2,46311420
asked Nov 21 '18 at 9:16
craig157craig157
155
I am receiving below error, when I try to set value on a JProgressBar.
"Optional cannot be converted to Int"
Could someone please advise any workarounds/Solution??
public GUI(){
initComponents();
tL = new TasksToDo();
jProgressBar1.setValue(tL.retrieveTotalHours());// [Where my error occurs]}
}
And from the TaskToDo Class, Originally I set this to ArrayList but the warnings said needed to switch to Optional:
public class TasksToDo {
public static ArrayList<Task> taskList;
public TasksToDo(){
taskList = new ArrayList<Task>();
taskList.add(new Task(0,"Whitepaper", "Write first draft of Whitepaper", 7));
taskList.add(new Task(1,"Create Database Structure", "Plan required fields and tables", 1));
taskList.add(new Task(2,"Setup ODBC Connections", "Create the ODBC Connections between SVR1 to DEV-SVR", 2));
}
public void addTask (int taskId, String taskTitle, String taskDescription, int taskHours){}
public ArrayList<Task> retrieveTask(){
return taskList;
}
public Optional<Integer> retrieveTotalHours(){
return taskList.stream().map(e -> e.getTaskHours()).reduce(Integer::sum);
}
}
java netbeans stream optional jprogressbar
java netbeans stream optional jprogressbar
edited Nov 21 '18 at 10:53
Suryavel TR
2,46311420
asked Nov 21 '18 at 9:16
craig157craig157
155
edited Nov 21 '18 at 10:53
Suryavel TR
2,46311420
asked Nov 21 '18 at 9:16
craig157craig157
155
edited Nov 21 '18 at 10:53
Suryavel TR
2,46311420
edited Nov 21 '18 at 10:53
Suryavel TR
2,46311420
edited Nov 21 '18 at 10:53
Suryavel TR
2,46311420
2,46311420
asked Nov 21 '18 at 9:16
craig157craig157
155
asked Nov 21 '18 at 9:16
craig157craig157
155
asked Nov 21 '18 at 9:16
craig157craig157
155
155
add a comment |
add a comment |
4 Answers
4
active
oldest
votes
You have to unwrap the optional and grab the value in it like this. Otherwise you can't assign an Optional where int is needed.
tL.retrieveTotalHours().orElse(0);
answered Nov 21 '18 at 9:21
Ravindra RanwalaRavindra Ranwala
9,34731636
1
That's worked perfectly! Thanks Ravindra
– craig157
Nov 21 '18 at 9:41
add a comment |
An Optional means that the value need not be there. It is basically there to force the caller to explicitly decide what to when a value does not exist. In your case, you can specifify a default value:
jProgressBar1.setValue(tL.retrieveTotalHours().orElse(0));
However, your retrieveTotalHours method probably should not return an Optional in the first place. Stream.reduce returns Optional.empty() when the stream is empty, but in your case it probably should return 0 when the list of tasks is empty. So you can do:
public int retrieveTotalHours(){
return taskList.stream().map(e -> e.getTaskHours()).reduce(0, Integer::sum);
}
(The 0 argument is the identity, which is returned when the stream is empty.)
or even:
public int retrieveTotalHours(){
return taskList.stream().mapToInt(e -> e.getTaskHours()).sum();
}
answered Nov 21 '18 at 9:39
HoopjeHoopje
10k52544
Thank you for breaking it down Hoopje
– craig157
Nov 21 '18 at 10:38
add a comment |
Well, basically, an Optional<Integer> is not assignment compatible with int.
But Integer is (after unboxing) ... so change:
jProgressBar1.setValue(tL.retrieveTotalHours());
to
jProgressBar1.setValue(tL.retrieveTotalHours().orElse(0));
Note that you must provide an integer value when you call setValue. Null or "nothing" is not acceptable.
answered Nov 21 '18 at 9:24
Stephen CStephen C
518k70572928
Thanks Stephen - the orElse(0) did the trick! And yes this field must have a value over 0.1
– craig157
Nov 21 '18 at 9:42
add a comment |
If you are only interested in the sum of hours, you don't need the Optional and can make it simpler:
public int retrieveTotalHours()
{
return taskList.stream().mapToInt(e -> e.getTaskHours()).sum();
}
answered Nov 21 '18 at 9:40
rogerklrogerkl
312
Thanks Roger - I will be doing this on another field so will try your method too
– craig157
Nov 21 '18 at 9:44
add a comment |
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
You have to unwrap the optional and grab the value in it like this. Otherwise you can't assign an Optional where int is needed.
tL.retrieveTotalHours().orElse(0);
answered Nov 21 '18 at 9:21
Ravindra RanwalaRavindra Ranwala
9,34731636
1
That's worked perfectly! Thanks Ravindra
– craig157
Nov 21 '18 at 9:41
add a comment |
You have to unwrap the optional and grab the value in it like this. Otherwise you can't assign an Optional where int is needed.
tL.retrieveTotalHours().orElse(0);
answered Nov 21 '18 at 9:21
Ravindra RanwalaRavindra Ranwala
9,34731636
1
That's worked perfectly! Thanks Ravindra
– craig157
Nov 21 '18 at 9:41
add a comment |
You have to unwrap the optional and grab the value in it like this. Otherwise you can't assign an Optional where int is needed.
tL.retrieveTotalHours().orElse(0);
answered Nov 21 '18 at 9:21
Ravindra RanwalaRavindra Ranwala
9,34731636
You have to unwrap the optional and grab the value in it like this. Otherwise you can't assign an Optional where int is needed.
tL.retrieveTotalHours().orElse(0);
answered Nov 21 '18 at 9:21
Ravindra RanwalaRavindra Ranwala
9,34731636
answered Nov 21 '18 at 9:21
Ravindra RanwalaRavindra Ranwala
9,34731636
answered Nov 21 '18 at 9:21
Ravindra RanwalaRavindra Ranwala
9,34731636
answered Nov 21 '18 at 9:21
Ravindra RanwalaRavindra Ranwala
9,34731636
9,34731636
1
That's worked perfectly! Thanks Ravindra
– craig157
Nov 21 '18 at 9:41
add a comment |
1
That's worked perfectly! Thanks Ravindra
– craig157
Nov 21 '18 at 9:41
1
1
That's worked perfectly! Thanks Ravindra
– craig157
Nov 21 '18 at 9:41
That's worked perfectly! Thanks Ravindra
– craig157
Nov 21 '18 at 9:41
add a comment |
An Optional means that the value need not be there. It is basically there to force the caller to explicitly decide what to when a value does not exist. In your case, you can specifify a default value:
jProgressBar1.setValue(tL.retrieveTotalHours().orElse(0));
However, your retrieveTotalHours method probably should not return an Optional in the first place. Stream.reduce returns Optional.empty() when the stream is empty, but in your case it probably should return 0 when the list of tasks is empty. So you can do:
public int retrieveTotalHours(){
return taskList.stream().map(e -> e.getTaskHours()).reduce(0, Integer::sum);
}
(The 0 argument is the identity, which is returned when the stream is empty.)
or even:
public int retrieveTotalHours(){
return taskList.stream().mapToInt(e -> e.getTaskHours()).sum();
}
answered Nov 21 '18 at 9:39
HoopjeHoopje
10k52544
Thank you for breaking it down Hoopje
– craig157
Nov 21 '18 at 10:38
add a comment |
An Optional means that the value need not be there. It is basically there to force the caller to explicitly decide what to when a value does not exist. In your case, you can specifify a default value:
jProgressBar1.setValue(tL.retrieveTotalHours().orElse(0));
However, your retrieveTotalHours method probably should not return an Optional in the first place. Stream.reduce returns Optional.empty() when the stream is empty, but in your case it probably should return 0 when the list of tasks is empty. So you can do:
public int retrieveTotalHours(){
return taskList.stream().map(e -> e.getTaskHours()).reduce(0, Integer::sum);
}
(The 0 argument is the identity, which is returned when the stream is empty.)
or even:
public int retrieveTotalHours(){
return taskList.stream().mapToInt(e -> e.getTaskHours()).sum();
}
answered Nov 21 '18 at 9:39
HoopjeHoopje
10k52544
Thank you for breaking it down Hoopje
– craig157
Nov 21 '18 at 10:38
add a comment |
An Optional means that the value need not be there. It is basically there to force the caller to explicitly decide what to when a value does not exist. In your case, you can specifify a default value:
jProgressBar1.setValue(tL.retrieveTotalHours().orElse(0));
However, your retrieveTotalHours method probably should not return an Optional in the first place. Stream.reduce returns Optional.empty() when the stream is empty, but in your case it probably should return 0 when the list of tasks is empty. So you can do:
public int retrieveTotalHours(){
return taskList.stream().map(e -> e.getTaskHours()).reduce(0, Integer::sum);
}
(The 0 argument is the identity, which is returned when the stream is empty.)
or even:
public int retrieveTotalHours(){
return taskList.stream().mapToInt(e -> e.getTaskHours()).sum();
}
answered Nov 21 '18 at 9:39
HoopjeHoopje
10k52544
An Optional means that the value need not be there. It is basically there to force the caller to explicitly decide what to when a value does not exist. In your case, you can specifify a default value:
jProgressBar1.setValue(tL.retrieveTotalHours().orElse(0));
However, your retrieveTotalHours method probably should not return an Optional in the first place. Stream.reduce returns Optional.empty() when the stream is empty, but in your case it probably should return 0 when the list of tasks is empty. So you can do:
public int retrieveTotalHours(){
return taskList.stream().map(e -> e.getTaskHours()).reduce(0, Integer::sum);
}
(The 0 argument is the identity, which is returned when the stream is empty.)
or even:
public int retrieveTotalHours(){
return taskList.stream().mapToInt(e -> e.getTaskHours()).sum();
}
answered Nov 21 '18 at 9:39
HoopjeHoopje
10k52544
answered Nov 21 '18 at 9:39
HoopjeHoopje
10k52544
answered Nov 21 '18 at 9:39
HoopjeHoopje
10k52544
answered Nov 21 '18 at 9:39
HoopjeHoopje
10k52544
10k52544
Thank you for breaking it down Hoopje
– craig157
Nov 21 '18 at 10:38
add a comment |
Thank you for breaking it down Hoopje
– craig157
Nov 21 '18 at 10:38
Thank you for breaking it down Hoopje
– craig157
Nov 21 '18 at 10:38
Thank you for breaking it down Hoopje
– craig157
Nov 21 '18 at 10:38
add a comment |
Well, basically, an Optional<Integer> is not assignment compatible with int.
But Integer is (after unboxing) ... so change:
jProgressBar1.setValue(tL.retrieveTotalHours());
to
jProgressBar1.setValue(tL.retrieveTotalHours().orElse(0));
Note that you must provide an integer value when you call setValue. Null or "nothing" is not acceptable.
answered Nov 21 '18 at 9:24
Stephen CStephen C
518k70572928
Thanks Stephen - the orElse(0) did the trick! And yes this field must have a value over 0.1
– craig157
Nov 21 '18 at 9:42
add a comment |
Well, basically, an Optional<Integer> is not assignment compatible with int.
But Integer is (after unboxing) ... so change:
jProgressBar1.setValue(tL.retrieveTotalHours());
to
jProgressBar1.setValue(tL.retrieveTotalHours().orElse(0));
Note that you must provide an integer value when you call setValue. Null or "nothing" is not acceptable.
answered Nov 21 '18 at 9:24
Stephen CStephen C
518k70572928
Thanks Stephen - the orElse(0) did the trick! And yes this field must have a value over 0.1
– craig157
Nov 21 '18 at 9:42
add a comment |
Well, basically, an Optional<Integer> is not assignment compatible with int.
But Integer is (after unboxing) ... so change:
jProgressBar1.setValue(tL.retrieveTotalHours());
to
jProgressBar1.setValue(tL.retrieveTotalHours().orElse(0));
Note that you must provide an integer value when you call setValue. Null or "nothing" is not acceptable.
answered Nov 21 '18 at 9:24
Stephen CStephen C
518k70572928
Well, basically, an Optional<Integer> is not assignment compatible with int.
But Integer is (after unboxing) ... so change:
jProgressBar1.setValue(tL.retrieveTotalHours());
to
jProgressBar1.setValue(tL.retrieveTotalHours().orElse(0));
Note that you must provide an integer value when you call setValue. Null or "nothing" is not acceptable.
answered Nov 21 '18 at 9:24
Stephen CStephen C
518k70572928
answered Nov 21 '18 at 9:24
Stephen CStephen C
518k70572928
answered Nov 21 '18 at 9:24
Stephen CStephen C
518k70572928
answered Nov 21 '18 at 9:24
Stephen CStephen C
518k70572928
518k70572928
Thanks Stephen - the orElse(0) did the trick! And yes this field must have a value over 0.1
– craig157
Nov 21 '18 at 9:42
add a comment |
Thanks Stephen - the orElse(0) did the trick! And yes this field must have a value over 0.1
– craig157
Nov 21 '18 at 9:42
Thanks Stephen - the orElse(0) did the trick! And yes this field must have a value over 0.1
– craig157
Nov 21 '18 at 9:42
Thanks Stephen - the orElse(0) did the trick! And yes this field must have a value over 0.1
– craig157
Nov 21 '18 at 9:42
add a comment |
If you are only interested in the sum of hours, you don't need the Optional and can make it simpler:
public int retrieveTotalHours()
{
return taskList.stream().mapToInt(e -> e.getTaskHours()).sum();
}
answered Nov 21 '18 at 9:40
rogerklrogerkl
312
Thanks Roger - I will be doing this on another field so will try your method too
– craig157
Nov 21 '18 at 9:44
add a comment |
If you are only interested in the sum of hours, you don't need the Optional and can make it simpler:
public int retrieveTotalHours()
{
return taskList.stream().mapToInt(e -> e.getTaskHours()).sum();
}
answered Nov 21 '18 at 9:40
rogerklrogerkl
312
Thanks Roger - I will be doing this on another field so will try your method too
– craig157
Nov 21 '18 at 9:44
add a comment |
If you are only interested in the sum of hours, you don't need the Optional and can make it simpler:
public int retrieveTotalHours()
{
return taskList.stream().mapToInt(e -> e.getTaskHours()).sum();
}
answered Nov 21 '18 at 9:40
rogerklrogerkl
312
If you are only interested in the sum of hours, you don't need the Optional and can make it simpler:
public int retrieveTotalHours()
{
return taskList.stream().mapToInt(e -> e.getTaskHours()).sum();
}
answered Nov 21 '18 at 9:40
rogerklrogerkl
312
answered Nov 21 '18 at 9:40
rogerklrogerkl
312
answered Nov 21 '18 at 9:40
rogerklrogerkl
312
answered Nov 21 '18 at 9:40
rogerklrogerkl
312
312
Thanks Roger - I will be doing this on another field so will try your method too
– craig157
Nov 21 '18 at 9:44
add a comment |
Thanks Roger - I will be doing this on another field so will try your method too
– craig157
Nov 21 '18 at 9:44
Thanks Roger - I will be doing this on another field so will try your method too
– craig157
Nov 21 '18 at 9:44
Thanks Roger - I will be doing this on another field so will try your method too
– craig157
Nov 21 '18 at 9:44
add a comment |
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