How to display all employee details on the basis of name as input given by user-CodePudding

I am trying to prepare an employee search program.

Requirement: I have an ArrayList "employee" which is holding data of multiple employees (like : name, employeeID, location, DOJ, etc). Now I need to prepare a method say "findEmployee" which will have "name" as input and it return all the associated details with that employee. In case no such employee found then it should throw an exception.

What I have written:

private static List<Employee> employee = new ArrayList<>();

public Employee findEmployee(String Name) throws emplyeeNotFoundException {
 for(Employee value : employee) {
  if(value.getName().equals(Name)) {
  return value;
 }
 else {
  throw new emplyeeNotFoundException(Name);
 }
}
}

Here Employee is the main class and getName() is the method to get the name of employee.

Issue: I am aware that above logic will not work as it will throw exception every time if condition does not meet the requirement. Can anyone suggest me how I need to write this code so that it will check the complete employee list and only throw exception when no data found? Also if it found the employee name in arraylist it should return all its details and come out of loop.

CodePudding user response：

public Employee findEmployee(String Name) throws emplyeeNotFoundException {
    boolean isFound = false;
    for(Employee value : employee) {
        if(value.getName().equals(Name)) {
            return value;
        }
    }
    throw new emplyeeNotFoundException(Name); 
}

If the value is present, returns the value.
If not present, the loop ends and at this point nothing is returned. Hence the Exception is thrown.

CodePudding user response：

You can throw exception after loop over all the array (meaning you dont fount any employee), and if do found the function will end on the return.

private static List<Employee> employee = new ArrayList<>();

public Employee findEmployee(String Name) throws emplyeeNotFoundException {
  for(Employee value : employee) {
    if(value.getName().equals(Name)) {
      return value;
    }
  }
  throw new emplyeeNotFoundException(Name);
}

CodePudding user response：

Stream-based solution

You can use apply filter() with your condition and then findFirst() as a terminal operation, which will produce an optional result Optional<Employee>.

And finally, apply orElseThrow() on the optional object, that will either retrieve the employee or will throw an exception if optional is empty.

One of the flavors on orElseThrow() expects a supplier as an argument, so we can the exception that be thrown if result wasn't found.

return employee.stream()
    .filter(emp -> emp.getName().equals(name))
    .findFirst()
    .orElseThrow(() -> new EmplyeeNotFoundException(name));

Sidenote:

adhere to the Java naming conventions when you're giving names to your classes, methods, etc. Names of classes should start with a capital letter - EmplyeeNotFoundException, and variable-name with a lower case letter - name.