Package com.identityworksllc.iiq.common.iterators

Class BatchingIterator<ObjectType>

java.lang.Object

com.identityworksllc.iiq.common.iterators.BatchingIterator<ObjectType>

Type Parameters:

ObjectType -

All Implemented Interfaces:

AutoCloseable, Iterator<List<ObjectType>>, sailpoint.tools.CloseableIterator<List<ObjectType>>

public class BatchingIterator<ObjectType>
extends Object
implements AutoCloseable, sailpoint.tools.CloseableIterator<List<ObjectType>>, Iterator<List<ObjectType>>

An iterator that batches up the inputs into batches of size ‘batchSize’, then returns them in chunks.

The last batch may, of course, be smaller than the batch size.

Similar to the Guava Iterators.partition(Iterator, int)

Constructor Summary

Constructors

Constructor	Description
BatchingIterator(Iterator<? extends ObjectType> input, int batchSize)	Constructor

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the iterator by flushing the input iterator
boolean	hasNext()	Retrieves the next batch of items and returns true if the batch is not empty.
List<ObjectType>	next()	Returns the next item, which is derived during hasNext().

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, remove

Constructor Detail

BatchingIterator

public BatchingIterator(Iterator<? extends ObjectType> input,
                        int batchSize)

Constructor

Parameters:

input - The iterator being wrapped by this transformer

batchSize - The batch size

Method Detail

close

public void close()

Closes the iterator by flushing the input iterator

Specified by:

close in interface AutoCloseable

Specified by:

close in interface sailpoint.tools.CloseableIterator<ObjectType>

hasNext

public boolean hasNext()

Retrieves the next batch of items and returns true if the batch is not empty.

Note that if this iterator wraps something slow (e.g., an iterator that is streaming from disk or something), hasNext() will take a while.

You MUST call hasNext() before any call to next() will work properly.

Specified by:

hasNext in interface sailpoint.tools.CloseableIterator<ObjectType>

Specified by:

hasNext in interface Iterator<ObjectType>

Returns:

True if the batch is not empty and next() will return a value

next

public List<ObjectType> next()

Returns the next item, which is derived during hasNext().

The result is always an immutable copy of the internal state of this class.

Specified by:

next in interface sailpoint.tools.CloseableIterator<ObjectType>

Specified by:

next in interface Iterator<ObjectType>

Returns:

The next item

Throws:

NoSuchElementException - if hasNext() has not been invoked or if it returned false