I am using java 8
I have a model class like
class Student{
String name;
List<Subject> subjects1;
List<Subject> subjects2;
List<Subject> subjects3;
// getters & setters
}
class Subject{
String sub;
Integer marks;
boolean status;
// getters & setters
}
status may be true or false.
Now if the status is false then I have to remove those objects from the subjects list
How to do it in Streams?
Thanks in advance.
To remove objects, you can directly use removeIf method in java 8.
student.getSubjects().removeIf(subject -> !subject.isStatus());
Here's how you do it:
List<Student> studentsWithTrueStatus = students
.stream()
.filter( s -> s.status )
.collect(Collectors.toList());
students. It does not really remove anything.
If there are multiple lists of Subject in Student class, they may be joined using Stream.of and then applying removeIf in forEach:
// Some utility class MyClass
public static void removeSubjects(Student student) {
Stream.of(student.getSubjects1(), student.getSubjects2(), student.getSubjects3())
.filter(Objects::nonNull) // filter out null lists if any
.forEach(subjects -> subjects.removeIf(sub -> !sub.isStatus()));
}
If there is a list of students, then the reference to the above implemented method may be used for each student:
List<Students> students = Arrays.asList(...); // setup students list
students.forEach(MyClass::removeSubjects);
First ensure the list of subjects is not null or empty. Then utilise removeIf() method.
List<Subject> subjectList = student.getSubjects();
if((null != subjectList) && (subjectList.size() > 0)) {
subjectList.removeIf(sub -> !(sub.isStatus()));
}
