I am trying to implement a toArray() method on a list. Initially I got an error saying I could only iterate over an array or an instance of java.lang.iterable when using the for each loop, so I did some research and tried using the Iterator. However, now it looks like it's stuck in something like a recursive loop (I think). Here is the section of my code I'm having trouble with:
public Object[] toArray(){
Object[] arr = new Object[this.size()]
int i = 0;
for(E e: this){
arr[i] = e;
i++;
}
return arr;
}
@Override
public Iterator<E> iterator() {
return this.iterator();
}
I've narrowed it down to how I've defined my public Iterator<E> iterator()
method since the program works ok if I use other values instead of this
in the foreach loop. The error I'm getting is Exception in thread "main"java.lang.StackOverflowError at arrayIndexList.ArrayIndexList.iterator(ArrayIndexList.java:158)
repeated exactly as it is over and over again, but not in an infinite loop since it terminates. When I click ArrayIndexList.java:158
it takes me to the return this.iterator()
in my code. What am I missing here?
First, you need to pass the Class<E>
to your constructor and save it so you can construct your array type properly in toArray()
- and return an E[]
. Then you can wrap that with a List
and return the iterator()
of that. Like,
private Class<E> cls; // <-- make sure you assign this in your constructor
public E[] toArray() {
E[] arr = Array.newInstance(cls, this.size()); // <-- here is how you get an E[]
int i = 0;
for (E e : this) {
arr[i] = e;
i++;
}
return arr;
}
@Override
public Iterator<E> iterator() {
return Arrays.asList(this.toArray()).iterator();
}
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