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## org.neo4j.helpers.collection
Class PagingIterator<T>

    java.lang.Object
      org.neo4j.helpers.collection.CachingIterator<T>
          org.neo4j.helpers.collection.PagingIterator<T>

Type Parameters:
  `T` - the type of items in this iterator.

All Implemented Interfaces:
  Iterator<T>, ListIterator<T>

    public class PagingIterator<T>

extends CachingIterator<T>

A `CachingIterator` which can more easily divide the items into pages, where optionally each page can be seen as its own `Iterator` instance for convenience using `nextPage()`.

Author:
  Mattias Persson

Constructor Summary
`PagingIterator(Iterator<T> source, int pageSize)` Creates a new paging iterator with `source` as its underlying `Iterator` to lazily get items from.

Method Summary
`Iterator<T>` | `nextPage()` Returns a new `Iterator` instance which exposes the current page as its own iterator, which fetches items lazily from the underlying iterator.
`int` | `page()`
`int` | `page(int newPage)` Sets the current page of the iterator.

Methods inherited from class org.neo4j.helpers.collection.CachingIterator
`add, current, hasNext, hasPrevious, next, nextIndex, position, position, previous, previousIndex, remove, set`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### PagingIterator

    public PagingIterator(Iterator<T> source,
                          int pageSize)

  Creates a new paging iterator with `source` as its underlying `Iterator` to lazily get items from.

  Parameters:
    `source` - the underlying `Iterator` to lazily get items from.
    `pageSize` - the max number of items in each page.

Method Detail

### page

    public int page()

  Returns:
    the page the iterator is currently at, starting a `0`. This value is based on the `CachingIterator.position()` and the page size.

### page

    public int page(int newPage)

  Sets the current page of the iterator. `0` means the first page.

  Parameters:
    `newPage` - the current page to set for the iterator, must be non-negative. The next item returned by the iterator will be the first item in that page.
  Returns:
    the page before changing to the new page.

### nextPage

    public Iterator<T> nextPage()

  Returns a new `Iterator` instance which exposes the current page as its own iterator, which fetches items lazily from the underlying iterator. It is discouraged to use an `Iterator` returned from this method at the same time as using methods like `CachingIterator.next()` or `CachingIterator.previous()`, where the results may be unpredictable. So either use only `nextPage()` (in conjunction with `page(int)` if necessary) or go with regular `CachingIterator.next()`/`CachingIterator.previous()`.

  Returns:
    the next page as an `Iterator`.

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