I have a requirement to get the count of employees where employee name contains "kumar" and age is greater than 26. I am using Java 8 streams to iterate over the collection and I'm able to find employee count with above said condition.
But, in the meantime, I need to print the employee details.
Here's my code using Java 8 streams:
public static void main(String[] args) {
List<Employee> empList = new ArrayList<>();
empList.add(new Employee("john kumar", 25));
empList.add(new Employee("raja", 28));
empList.add(new Employee("hari kumar", 30));
long count = empList.stream().filter(e -> e.getName().contains("kumar"))
.filter(e -> e.getAge() > 26).count();
System.out.println(count);
}
Traditional way:
public static void main(String[] args){
List<Employee> empList = new ArrayList<>();
empList.add(new Employee("john kumar", 25));
empList.add(new Employee("raja", 28));
empList.add(new Employee("hari kumar", 30));
int count = 0;
for (Employee employee : empList) {
if(employee.getName().contains("kumar")){
if(employee.getAge() > 26)
{
System.out.println("emp details :: " + employee.toString());
count++;
}
}
}
System.out.println(count);
}
Whatever I am printing in the traditional way, I want to achieve the same using streams also.
How do I print a message within each iteration when using streams?
You could use the Stream.peek(action)
method to log info about each object of your stream :
long count = empList.stream().filter(e -> e.getName().contains("kumar"))
.filter(e -> e.getAge() > 26)
.peek(System.out::println)
.count();
The peek
method allows performing an action on each element from the stream as they are consumed. The action must conform to the Consumer
interface: take a single parameter t
of type T
(type of the stream element) and return void
.
Rather unclear, what you actually want, but this might help:
Lambdas (like your Predicate
) can be written in two ways:
Without brackets like this: e -> e.getAge() > 26
or
...filter(e -> {
//do whatever you want to do with e here
return e -> e.getAge() > 26;
})...
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