CODEWITHSUNDEEP
java
Max_Salah
Max_Salah

Reputation: 2497

How to implement Blacklist in java

I would like to implement a method isInBlackList(String element), which return true, if element is founded in the blacklist. I have the following code:

public boolean isInBlackList(String element) {
        Set<String> blackList = new HashSet<String>();
        blackList.add("element1");
        blackList.add("element2");
        ...
        .....
        blackList.add("element20");

        return blackList.contains(element);
    }

What is bothering me is that I have to write add() method 20 times. Any better idea? it does not have to be implemented with Set.

Upvotes: 1

Views: 5427

Answers (5)

newuser
newuser

Reputation: 8466

Try this way,

Set<String> blackList = new HashSet<String>();

    public static void main(String[] args)
    {
        Test12 ss = new Test12();
        ss.populateBlackList();  // if the blacklist is fixed means you can call this in constructor 
        System.out.println(ss.isInBlackList("element1"));
    }

    private void populateBlackList() // make it as an seperate method dont populate at all time
    {
        for (int i = 1; i <= 20; i++)
        {
            blackList.add("element" + i);
        }
    }

    public boolean isInBlackList(String element) //finding the blackList
    {
        return blackList.contains(element);
    }

Upvotes: 1

Patrick
Patrick

Reputation: 831

You can make blacklist a field of your class and initialize it with :

Set<String> blackList = new HashSet<String>(Arrays.asList("element1", ...));

Upvotes: 1

Rahul Tripathi
Rahul Tripathi

Reputation: 172528

You may try like this:

Set<String> blackList = new HashSet<String>(Arrays.asList("element1", "element2", "element3"));

Upvotes: 3

ccjmne
ccjmne

Reputation: 9628

The simplest way I can think of is the following:

final List<String> blackList = Arrays.asList("element1", "element2", "element3");

As you can see, that's... really minimalist, and still works :)

Upvotes: 2

stinepike
stinepike

Reputation: 54692

  1. declare blackList as a member variable and initialize it in constructor.

  2. just use a for loop to add the elements

    for( int i = 1; i<=20; i++){ 

    string s = "element"+i;
    blackList.add(s);
}

Upvotes: 0

Related Questions