CODEWITHSUNDEEP
javaarraylistiterator
JAN
JAN

Reputation: 21875

Re-initialization of iterator of ArrayList does not work

Given the following : 

    // get the list of the players , in order to start the game 
    ArrayList<String> players = this.m_maze.getPlayers();
    // human side 
    String humanPlayer = iterator.next();
    String computerPlayer = null;
    // define iterator for the players 

    Iterator<String> iterator = players.iterator();     
    boolean humanSide = true ,computerSide = false;    // assume the human player is starting the game 


    // controller - start a game between the players , at least two players are playing 

    while (this.m_rounds > 0)  
    {

        if (humanSide == false && computerSide == true) // then this is the turn of the human side 
        {
            if (iterator.hasNext() == false)
            {
                // reinitialize the iterator
                Iterator<String> iterator = players.iterator();

            }
            while (iterator.hasNext())


                        // more code

I try to reuse the iterator but I get a "Duplicate local variable iterator" compilation error. How can I reuse that iterator ? Thanks ,Ron

EDIT :

            if (iterator.hasNext() == false)
            {
                // reinitialize the iterator
                iterator = players.iterator();

            }
            while (iterator.hasNext())
            {
                computerPlayer = iterator.next();

                // computer decides what would be his next move , between 1 - 3

Upvotes: 0

Views: 2592

Answers (5)

Navneeth G
Navneeth G

Reputation: 7305

Don't use iterators like this, it can mess things up, just do it the old way, I mean using the famous Mr. Iterator "i". Moreover the code would look more sensible.

    while(m_rounds > 0){

        if(i == players.size()) {
            i = 0;
        }

        currentPlayer = players.get(i);

        //Do what you want to do with the current player...

        ...

        //Next
        i++;


    }

A small suggestion, do you really need both the flags, i mean the humanSide and computerSide? Won't using just one suffice? Your if-else block would look a lot more simpler and clear:

if(humanSide) {

   //Hope this move wouldn't crush your logic.

} else {

  //Algorithm based awesome move.

}

Upvotes: 1

clstrfsck
clstrfsck

Reputation: 14837

I think google guava has pretty much what you want with Iterators#cycle.

Use it like this:

    Iterator<String> iterator = Iterators.cycle(players.iterator());

...and you will never run out of players.

Upvotes: 1

JAN
JAN

Reputation: 21875

Okay just remove the Iterator<String> , meaning is , when reusing that iterator just write : iterator = players.iterator();

Thank you all !!

Upvotes: 0

cheeken
cheeken

Reputation: 34675

Don't re-declare the variable; just assign it.

if (iterator.hasNext() == false) {
    iterator = players.iterator();
}

You should be careful about nested loop behavior. Is your real intent to have have the following block

while (iterator.hasNext()) { ... }

actually check for this condition?

while (iterator.hasNext() && (this.m_rounds > 0)) { ... }

Upvotes: 3

gprathour
gprathour

Reputation: 15333

You have put Iterator<String> iterator = players.iterator(); in your loop.

So each time it tries to create variable with name iterator.

Just put it's declaration out of the loop... like 

 Iterator<String> iterator;     //here ****
 while (this.m_rounds > 0)  
   {

    if (humanSide == false && computerSide == true) // then this is the turn of the human side 
    {
        if (iterator.hasNext() == false)
        {
            // reinitialize the iterator
            iterator = players.iterator();

        }
        while (iterator.hasNext())

Upvotes: 1

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