Package com.puresoltechnologies.streaming.iterators

Class CountingStreamIterator<T>

java.lang.Object

com.puresoltechnologies.streaming.iterators.CountingStreamIterator<T>

Type Parameters:

T -

All Implemented Interfaces:

StreamIterator<T>, Iterator<T>

public class CountingStreamIterator<T>
extends Object
implements StreamIterator<T>

This is an Iterator decorator to count the elements retrieved via next().

Author:

Rick-Rainer Ludwig

Constructor Summary

Constructors

Constructor	Description
CountingStreamIterator(StreamIterator<T> origin)
CountingStreamIterator(Iterator<T> origin)

Method Summary

Modifier and Type	Method	Description
long	getCount()	Returns the count of the elements retrieved by next() so far.
boolean	hasNext()
T	next()	This method overwrites Iterator.next() with a one change: The resulting element is never null.
static <V,I extends Iterator<V>> CountingStreamIterator<V>	of(I streamIterator)	This method
T	peek()	This method returns the next element which will be returned by next(), without moving forward.

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.puresoltechnologies.streaming.iterators.StreamIterator

empty, filter, flatMap, map, spliterator, stream

Constructor Detail

CountingStreamIterator

public CountingStreamIterator(Iterator<T> origin)

CountingStreamIterator

public CountingStreamIterator(StreamIterator<T> origin)

Method Detail

of

public static <V,I extends Iterator<V>> CountingStreamIterator<V> of(I streamIterator)

This method

Parameters:

streamIterator -

Returns:

getCount

public final long getCount()

Returns the count of the elements retrieved by next() so far.

Returns:

A long is returned providing the current count.

hasNext

public final boolean hasNext()

Specified by:

hasNext in interface Iterator<T>

next

public final T next()
             throws NoSuchElementException

Description copied from interface: StreamIterator

This method overwrites Iterator.next() with a one change: The resulting element is never null.

Specified by:

next in interface Iterator<T>

Specified by:

next in interface StreamIterator<T>

Returns:

An object of generic type T is returned. If the stream has reached its end, a NoSuchElementException is thrown. Iterator.hasNext() will returned false in this case and should be asked for the presence of more elements in advance. The result is never null.

Throws:

NoSuchElementException - is thrown in case the stream has reached its end.

peek

public final T peek()
             throws NoSuchElementException

Description copied from interface: StreamIterator

This method returns the next element which will be returned by next(), without moving forward.

Specified by:

peek in interface StreamIterator<T>

Returns:

An object of generic type T is returned. If the stream has reached its end, a NoSuchElementException is thrown. Iterator.hasNext() will returned false in this case and should be asked for the presence of more elements in advance. The result is never null.

Throws:

NoSuchElementException - is thrown in case the stream has reached its end.