Best way to compare an iterator values and an enum for matching values in java

I have an iterator that loops through a values with a simple hasNext() function. I also have an enum that contains certain values. I would like to find all the matching values between the enum and the iterator.

I'm trying to do this hopefully with the best performance both runtime and space wise.
Thanks.

For reference to code (it's a simple straightforward case but feel free to ask for more code:

Iterator iterator = user.userTasks.iterator(); //loops through current users tasks
        while(iterator.hasNext()) {
            UserTask userTask = (userTask)iterator.next();
            //want to compare userTask above with values from a java enum for any matches

The enum has a string field and that is what I'm trying to match to this iterators field too. So, a field of the iterator to a field of the enum.

Based on your description, you need to match the enum field with and Iterator field.

First lets create an ENUM with a String field.
<!-- language: java -->
public enum ExampleEnum {

    ONE("one"),
    TWO("two"),
    THREE("three"),
    FOUR("four");
    
    private String eName;
	 
    ExampleEnum(String eName) {
        this.eName = eName;
    }
    
    public String geteName(){
        return eName;
    }
    
    public static Stream<ExampleEnum> stream() {
        return Stream.of(ExampleEnum.values()); 
    }
}

Use a simple ArrayList as an Iterator in your case replace it with UserTask Iterator.

<!-- language: java -->

String[] arr = {"one", "five", "six", "three", "eleven", "two", "four"};
List<String> arrayList = Arrays.asList(arr);
Iterator<String> iterator = arrayList.iterator();

while(iterator.hasNext()){
    String compare = iterator.next();
	ExampleEnum.stream()
    .filter(d -> d.geteName().equals(compare))
    .forEach(System.out::println);
}

I'm using Java 8, I guess in Java 9 can be done more easily.