How to compare an element from ArrayList with a specific String?

Question

I am currently working on a quiz game. In the following public void Run(), I want to validate the user input String answerwith the correct answers: answersList.forEach(new String.

I am trying to do this with a boolean. But I receive this error message: "Cannot resolve constructor 'String(boolean)'. How do I do to solve this issue?

Initialization of the private volatile boolean:

class Broadcaster extends Thread {
private volatile boolean check_point = true;

public boolean getFlag() {
    System.out.println("getFlag is running");
    return this.check_point;

}

And after BufferedReader, PrintStrem and so on...

  public void run() {
    while (true) {
        try {
            List<String> answersList = new ArrayList<>();
            try (Stream<String> answersStream = Files.lines(Paths.get(answersFile))) {
                answersList = answersStream
                        .map(String::toLowerCase)
                        .collect(Collectors.toList());
            } catch (IOException a) {
                a.printStackTrace();
                System.out.println("The timer isn't working correctly");
            }
            if (answersList.forEach(new String(equals(answer)))) { //ERROR MESSAGE
                write.println("Right Answer");
                points++;
                check_point = true;

            } else {
                write.println("Wrong Answer");
                check_point = false;
            }
        } catch (Exception e) {
            System.out.println("Some problem with the validation");
         }
     }
   }
}

the problem is that you're passing the result of "equals(answer)" which is a boolean value to the constructor of the String hence there is no String constructor which takes a boolean value and even if you were to remove the "equals()" you'd still get an error because the forEach method accepts a Consumer. please specify all the code needed and what you want the end result to be. — Ousmane D.
– Ousmane D., Commented Apr 7, 2017 at 20:01

Ousmane D. · Accepted Answer · 2017-04-07 20:13:11Z

1

But I receive this error message: "Cannot resolve constructor 'String(boolean)'. How do I do to solve this issue?

the problem is that you're passing the result of "equals(answer)" which is a boolean value to the constructor of the String hence there is no String constructor which takes a boolean value.

now to solve the issue you can either use lambda expression like this:

if(answersList.stream().anyMatch(str -> str.equals(answer))){
    write.println("Right Answer");
    points++;
    check_point = true;
}else{
    write.println("Wrong Answer");
    check_point = false;    
}

or simply:

if(answersList.contains(answer)){
    write.println("Right Answer");
    points++;
    check_point = true;
}else{
   write.println("Wrong Answer");
   check_point = false;
}

edited Apr 7, 2017 at 20:13

answered Apr 7, 2017 at 20:06

Ousmane D.

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2 Comments

Josef Lundström Over a year ago

Thank you, Ousmane for your answer. I did accept this answer because it was according to what I tried to achieve in the first place. Thank you all who wanted to help me...

Ousmane D. Over a year ago

@JosefLundström glad to know it helped! :).

Ben Arnao · Accepted Answer · 2017-04-07 20:06:35Z

1

For the same reason String s = new String(false); results in an error, you can't create a string object from a boolean value.

try this...

if (answersList.forEach(new String(Boolean.toString(equals(answer)))))

I feel like you're making what you're trying to do way more complicated than it has to be though...

answered Apr 7, 2017 at 20:06

Ben Arnao

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3 Comments

Ousmane D. Over a year ago

this wouldn't compile because the forEach takes as an argument a Consumer.

Ben Arnao Over a year ago

Why are you supplying it with a String then?

Ousmane D. Over a year ago

.anyMatch() returns a boolean value. as for the "forEach" a Consumer takes in an argument but doesn't return anything, that's basically what i am getting at.

Ousmane D. · Accepted Answer · 2017-04-07 20:36:16Z

1

I think the easiest way is to use

answersList.contains(answer)

instead of

answersList.forEach(new String(equals(answer)))

edited Apr 7, 2017 at 20:36

Ousmane D.

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answered Apr 7, 2017 at 20:02

Ivan Pronin

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