com.chemaxon.calculations.io

Interface CloseableIterator<T>

Type Parameters:

T - iterated type

All Superinterfaces:

java.lang.AutoCloseable, java.io.Closeable, java.util.Iterator<T>

All Known Implementing Classes:

com.chemaxon.calculations.io.CloseableAbstractIterator, MemoizingIterator, SmilesMemoizingMoleculeIterator

@Beta
 @PublicAPI
public interface CloseableIterator<T>
extends java.util.Iterator<T>, java.io.Closeable

Closeable iterator. The iterator requires explicit closing, reaching the last element should not result in implicit close. IOException potentially thrown from a delegate Closeable.close() is expected to be wrapped in to an IllegalStateException.

For providing an implementation one can use CloseableIterators.wrap(java.util.Iterator), CloseableIterators.wrap(java.util.Iterator, java.io.Closeable) or .

Please note that this interface is marked with @Beta annotation, so it can be subject of incompatible changes or removal in later releases.

Author:

Gabor Imre

Method Summary

Modifier and Type	Method and Description
default void	close()
default CloseableIterator<T>	forward(long maxItems) Forward this instance by discarding items.
default CloseableIterator<T>	limit(long limit) Return a view limiting the returned element count.
default CloseableIterator<T>	limit(long limit, java.util.function.Consumer<java.lang.Long> afterLimitReachedOrNull) Return a view limiting the returned element count.
default <U> CloseableIterator<U>	transform(java.util.function.Function<T,U> transformation) Apply a transformation of the elements of this Iterator.
default <U> CloseableIterator<U>	transformIterator(java.util.function.Function<java.util.Iterator<T>,java.util.Iterator<U>> processor) Apply a transformation on this Iterator.
default <U> CloseableIterator<U>	transformMultipleElements(java.util.function.Function<java.util.Iterator<T>,U> constructNext) Transform multiple elements into a single element.

Methods inherited from interface java.util.Iterator

forEachRemaining, hasNext, next, remove

Method Detail

close

default void close()
            throws java.lang.IllegalStateException

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface java.io.Closeable

Throws:

java.lang.IllegalStateException

transform

default <U> CloseableIterator<U> transform(java.util.function.Function<T,U> transformation)

Apply a transformation of the elements of this Iterator.

Type Parameters:

U - Transformed type

Parameters:

transformation - Transformation to apply on returned elements

Returns:

Transformed view of this Iterator

forward

default CloseableIterator<T> forward(long maxItems)

Forward this instance by discarding items.

Parameters:

maxItems - Item count to discard.

Returns:

Reference to this instance

limit

default CloseableIterator<T> limit(long limit)

Return a view limiting the returned element count.

Parameters:

limit - Max number of elements returned by the view

Returns:

limiting view

limit

default CloseableIterator<T> limit(long limit,
                                   java.util.function.Consumer<java.lang.Long> afterLimitReachedOrNull)

Return a view limiting the returned element count.

Parameters:

limit - Max number of elements returned by the view

afterLimitReachedOrNull - Optional callback to invoke when limit reached. Will be invoked from Iterator.hasNext() the first time it returns false. The role of this callback is to optionally sign that reading elements stopped because of reaching the specified limit. When no call made to Iterator.hasNext() after reaching this limit no callback invocation will be made. Also when when Iterator.next() invoked after reaching the limit it will throw a NoSuchElementException but no callback invocation will be made.

Returns:

limiting view

transformIterator

default <U> CloseableIterator<U> transformIterator(java.util.function.Function<java.util.Iterator<T>,java.util.Iterator<U>> processor)

Apply a transformation on this Iterator.

Type Parameters:

U - Type of transformed elements

Parameters:

processor - Function to call on this instance

Returns:

Transformed Iterator

transformMultipleElements

default <U> CloseableIterator<U> transformMultipleElements(java.util.function.Function<java.util.Iterator<T>,U> constructNext)

Transform multiple elements into a single element.

Type Parameters:

U - Type of transformed elements

Parameters:

constructNext - Function to create next element

Returns:

Transformed Iterator