com.google.common.collect
Class AbstractSequentialIterator<T>

java.lang.Object
  com.google.common.collect.UnmodifiableIterator<T>
      com.google.common.collect.AbstractSequentialIterator<T>

All Implemented Interfaces:

Iterator<T>

@GwtCompatible
public abstract class AbstractSequentialIterator<T>
extends UnmodifiableIterator<T>

This class provides a skeletal implementation of the Iterator interface for sequences whose next element can always be derived from the previous element. Null elements are not supported, nor is the UnmodifiableIterator.remove() method.

Example:

   Iterator<Integer> powersOfTwo = 
       new AbstractSequentialIterator<Integer>(1) {
         protected Integer computeNext(Integer previous) {
           return (previous == 1 << 30) ? null : previous * 2;
         }
       };

Since:

12.0 (in Guava as AbstractLinkedIterator since 8.0)

Author:

Chris Povirk

Constructor Summary

protected

AbstractSequentialIterator(T firstOrNull) Creates a new iterator with the given first element, or, if firstOrNull is null, creates a new empty iterator.

Method Summary

protected abstract T	computeNext(T previous) Returns the element that follows previous, or returns null if no elements remain.
boolean	hasNext()
T	next()

Methods inherited from class com.google.common.collect.UnmodifiableIterator

remove

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AbstractSequentialIterator

protected AbstractSequentialIterator(@Nullable
                                     T firstOrNull)

Creates a new iterator with the given first element, or, if firstOrNull is null, creates a new empty iterator.

Method Detail

computeNext

protected abstract T computeNext(T previous)

Returns the element that follows previous, or returns null if no elements remain. This method is invoked during each call to next() in order to compute the result of a future call to next().

hasNext

public final boolean hasNext()

next

public final T next()