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## org.neo4j.helpers.collection
Class IteratorUtil

    java.lang.Object
      org.neo4j.helpers.collection.IteratorUtil

    public abstract class IteratorUtil

extends Object

Contains common functionality regarding `Iterator`s.

Constructor Summary
`IteratorUtil()`

Method Summary
`static
`<C extends Collection<T>,T> C`
` | `addToCollection(Iterator<T> iterator, C collection)` Adds all the items in `iterator` to `collection`.
`static
`<T> Iterable<T>`
` | `asIterable(Iterator<T> iterator)` Exposes `iterator` as an `Iterable`.
`static
`<T> int`
` | `count(Iterator<T> iterator)` Counts the number of items in the `iterator` by looping through it.
`static
`<T> T`
` | `singleValueOrNull(Iterator<T> iterator)` Returns the given iterator's only value or `null` if there was no items in the iterator.

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

Constructor Detail

### IteratorUtil

    public IteratorUtil()

Method Detail

### singleValueOrNull

    public static <T> T singleValueOrNull(Iterator<T> iterator)

  Returns the given iterator's only value or `null` if there was no items in the iterator. If there is more than one value in the iterator an `IllegalArgumentException` will be thrown.

  Type Parameters:
    `T` - the type of items in `iterator`.
  Parameters:
    `iterator` - the `Iterator` to get items from.
  Returns:
    the only value in the `iterator`, or `null` if no value was found. Throws `IllegalArgumentException` if more than one value was found.

### addToCollection

    public static <C extends Collection<T>,T> C addToCollection(Iterator<T> iterator,
                                                                C collection)

  Adds all the items in `iterator` to `collection`.

  Type Parameters:
    `C` - the type of `Collection` to add to items to.
    `T` - the type of items in the collection and iterator.
  Parameters:
    `iterator` - the `Iterator` to grab the items from.
    `collection` - the `Collection` to add the items to.
  Returns:
    the `collection` which was passed in, now filled with the items from `iterator`.

### asIterable

    public static <T> Iterable<T> asIterable(Iterator<T> iterator)

  Exposes `iterator` as an `Iterable`. It breaks the contract of `Iterable` in that it returns the supplied iterator instance for each call to `iterable()` on the returned `Iterable` instance. This method mostly exists to make it easy to use an `Iterator` in a for-loop.

  Type Parameters:
    `T` - the type of items in the iterator.
  Parameters:
    `iterator` - the iterator to expose as an `Iterable`.
  Returns:
    the supplied iterator posing as an `Iterable`.

### count

    public static <T> int count(Iterator<T> iterator)

  Counts the number of items in the `iterator` by looping through it.

  Type Parameters:
    `T` - the type of items in the iterator.
  Parameters:
    `iterator` - the `Iterator` to count items in.
  Returns:
    the number of found in `iterator`.

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