CODEWITHSUNDEEP
javaif-statementjava-stream
user18665270
user18665270

Reputation: 69

How to rewrite For-loop and If-statement with Java 8 Streams

My code:

final List<Employee> empList= getEmployeeList();
String empid = "1234";
Employee selectedEmp = new Employee();

for (Employee e1: empList) {
    if (empid .equals(e1.getEmpid()))
        selectedEmp = e1;
    }
}

Now I want to rewrite the above code in Java 8.

I've tried the following, but without success. I can't figure out translate the if-statement:

empList.stream()
    .foreach( <how to apply if condition here>)

Upvotes: 0

Views: 305

Answers (1)

Alexander Ivanchenko
Alexander Ivanchenko

Reputation: 28988

forEach() isn't the appropriate tool here.

Firstly there's a method Iterable.forEach() which you can invoke directly on a list without creating a stream, secondly Stream.forEach() is not encouraged to be used in such a way by the Stream API documentation, it should be used with care in cases when you have no other tools suitable for the task.

Instead, you can use combination filter() + findFirst(), which produces result of type Optional.

To provide a default value for the case when employee wasn't found (like in your code a dummy Employee object created via no-args constructor) you can use Optional.orElseGet() which expects a Supplier that would be applied only when needed (when optional is empty).

public Employee findEmployee(String empid) {
    
    return getEmployeeList().stream()
        .filter(e -> empid.equals(e.getEmpid()))
        .findFirst()
        .orElseGet(Employee::new);
}

I strongly recommend you to get familiar with these tutorials on streams and lambda expressions

Upvotes: 8

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