Iterators.Abstract

java.lang.Object
- io.atlassian.fugue.Iterators.Unmodifiable<A>
- - io.atlassian.fugue.Iterators.Abstract<A>

All Implemented Interfaces:

java.util.Iterator<A>

Direct Known Subclasses:

Iterables.CollectingIterable.Iter, Iterables.Cycle.Iter, Iterables.Drop.Iter, Iterables.Join.Iter, Iterables.Memoizer.Iter, Iterables.MergeSortedIterable.Iter, Iterables.Take.Iter, Iterables.UnfoldingIterable.Iter

Enclosing class:

Iterators
```
abstract static class Iterators.Abstract<A>
extends Iterators.Unmodifiable<A>
```
A template implementation of the Iterator interface, so clients can more easily implement Iterator for some patterns of iteration.
An example is an iterator that skips over null elements in a backing iterator. This could be implemented as:
```
 

   public static Iterator<String> filterNulls(final Iterator<String> in) {
     return new AbstractIterator<String>() {
       protected String computeNext() {
         while (in.hasNext()) {
           String s = in.next();
           if (s != null) {
             return s;
           }
         }
         return endOfData();
       }
     };
   }
 
```
This class supports iterators that include null elements.
This class is a re-implentation of the Guava AbstractIterator class.
Since:

3.0

Nested Class Summary

Nested Classes
Modifier and Type Class Description

private static class Iterators.Abstract.State

Field Summary

Fields
Modifier and Type Field Description

private A next

private Iterators.Abstract.State state

Constructor Summary

Constructors
Modifier Constructor Description

protected Abstract()
Constructor for use by subclasses.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`protected abstract A`	`computeNext()`	The next element.
`protected A`	`endOfData()`	Implementations of `computeNext()` must invoke this method when there are no elements left in the iteration.
`boolean`	`hasNext()`
`A`	`next()`
`private boolean`	`tryToComputeNext()`

Methods inherited from class io.atlassian.fugue.Iterators.Unmodifiable
remove

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

Methods inherited from interface java.util.Iterator
forEachRemaining

- Field Detail
  - state
```
private Iterators.Abstract.State state
```
  - next
```
private A next
```
- Constructor Detail
  - Abstract
```
protected Abstract()
```
    Constructor for use by subclasses.
- Method Detail
  - computeNext
```
protected abstract A computeNext()
```
    The next element.
    Note: the implementation must call endOfData() when there are no elements left in the iteration. Failure to do so could result in an infinite loop.
  - endOfData
```
protected final A endOfData()
```
    Implementations of computeNext() must invoke this method when there are no elements left in the iteration.
    
    Returns:
    
    null; a convenience so your computeNext implementation can use the simple statement return endOfData();
  - hasNext
```
public final boolean hasNext()
```
  - tryToComputeNext
```
private boolean tryToComputeNext()
```
  - next
```
public final A next()
```