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Iterator Pattern

  • Method to move through (iterate through) the elements of something
  • Retrieve an iterator, which remembers its position and allows you to move to the next element
  • Retrieve/create an iterator, which remembers its position and allows you to move to the next element

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Java support for Iterator and Iterable​

Iterator interface exists. For each loops can be used with them - simplified version

public interface Iterator<T>{
    boolean hasNext();
    T next();
}

Iterable interface also exists, to create an Iterator.

Two interfaces to know​

  • Iterable (on the container to iterate through). Interface with a method to create an iterator
  • Iterator <T> iterator()
  • Iterator (object to do the iteration). Interface to allow checking if there is a next object and if so retrieving it and moving on
  • boolean hasNext() \n T next()