Package com.puresoltechnologies.streaming.iterators

Class AbstractStreamIterator<T>

java.lang.Object

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

Type Parameters:

T - is the element type of the iterator.

All Implemented Interfaces:

StreamIterator<T>, Iterator<T>

Direct Known Subclasses:

CompositeStreamIterator, ConvertingStreamIterator, FilteringStreamIterator, InputStreamIterator, StackedStreamIterator, StreamIteratorPipe

public abstract class AbstractStreamIterator<T>
extends Object
implements StreamIterator<T>

This is an abstract implementation of an iterator to be used as base class for more complex iterators to assure the Iterator contract. Because this is a stream iterator meant for complex streams, null values are not supported.

Author:

Rick-Rainer Ludwig

Constructor Summary

Constructors

Constructor	Description
AbstractStreamIterator()

Method Summary

Modifier and Type	Method	Description
protected abstract T	findNext()	This method looks for the next entry to be returned.
boolean	hasNext()
T	next()	This method overwrites Iterator.next() with a one change: The resulting element is never null.
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, of, spliterator, stream

Constructor Detail

AbstractStreamIterator

public AbstractStreamIterator()

Method Detail

findNext

protected abstract T findNext()

This method looks for the next entry to be returned. If no further entry is found, null is returned.

Returns:

An object of T is returned representing the next entry to be returned by the iterator. null is returned in case no more entries are available.

hasNext

public final boolean hasNext()

Specified by:

hasNext in interface Iterator<T>

next

public final T next()

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.

peek

public final T peek()

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.