org.apache.flink.runtime.operators.resettable

Class BlockResettableIterator<T>

java.lang.Object

org.apache.flink.runtime.operators.resettable.BlockResettableIterator<T>

All Implemented Interfaces:

Iterator<T>, MemoryBlockIterator, ResettableIterator<T>

public class BlockResettableIterator<T>
extends Object
implements ResettableIterator<T>

Implementation of an iterator that fetches a block of data into main memory and offers resettable access to the data in that block.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	closed
protected SimpleCollectingOutputView	collectingView
protected ArrayList<MemorySegment>	emptySegments
protected ArrayList<MemorySegment>	fullSegments
protected Iterator<T>	input
static org.slf4j.Logger	LOG
protected int	numRecordsInBuffer
protected int	numRecordsReturned
protected RandomAccessInputView	readView
protected TypeSerializer<T>	serializer

Constructor Summary

Constructors

Constructor and Description
BlockResettableIterator(MemoryManager memoryManager, Iterator<T> input, TypeSerializer<T> serializer, int numPages, AbstractInvokable ownerTask)
BlockResettableIterator(MemoryManager memoryManager, TypeSerializer<T> serializer, int numPages, AbstractInvokable ownerTask)

Method Summary

Modifier and Type	Method and Description
void	close() This method closes the iterator and releases all resources.
protected T	getNextRecord(T reuse)
boolean	hasFurtherInput() Checks, whether the input that is blocked by this iterator, has further elements available.
boolean	hasNext()
T	next()
boolean	nextBlock() Move the iterator to the next memory block.
void	open()
void	remove()
void	reopen(Iterator<T> input)
void	reset() Resets the iterator.
protected boolean	writeNextRecord(T record)

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

Field Detail

LOG

public static final org.slf4j.Logger LOG

input

protected Iterator<T> input

readView

protected final RandomAccessInputView readView

collectingView

protected final SimpleCollectingOutputView collectingView

serializer

protected final TypeSerializer<T> serializer

numRecordsInBuffer

protected int numRecordsInBuffer

numRecordsReturned

protected int numRecordsReturned

emptySegments

protected final ArrayList<MemorySegment> emptySegments

fullSegments

protected final ArrayList<MemorySegment> fullSegments

closed

protected volatile boolean closed

Constructor Detail

BlockResettableIterator

public BlockResettableIterator(MemoryManager memoryManager,
                               Iterator<T> input,
                               TypeSerializer<T> serializer,
                               int numPages,
                               AbstractInvokable ownerTask)
                        throws MemoryAllocationException

Throws:

MemoryAllocationException

BlockResettableIterator

public BlockResettableIterator(MemoryManager memoryManager,
                               TypeSerializer<T> serializer,
                               int numPages,
                               AbstractInvokable ownerTask)
                        throws MemoryAllocationException

Throws:

MemoryAllocationException

Method Detail

reopen

public void reopen(Iterator<T> input)
            throws IOException

Throws:

IOException

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<T>

next

public T next()

Specified by:

next in interface Iterator<T>

remove

public void remove()

Specified by:

remove in interface Iterator<T>

reset

public void reset()

Description copied from interface: ResettableIterator

Resets the iterator.

Specified by:

reset in interface ResettableIterator<T>

nextBlock

public boolean nextBlock()
                  throws IOException

Description copied from interface: MemoryBlockIterator

Move the iterator to the next memory block. The next memory block starts at the first element that was not in the block before. A special case is when no record was in the block before, which happens when this function is invoked two times directly in a sequence, without calling hasNext() or next in between. Then the block moves one element.

Specified by:

nextBlock in interface MemoryBlockIterator

Returns:

True if a new memory block was loaded, false if there were no further records and hence no further memory block.

Throws:

IOException - Thrown, when advancing to the next block failed.

hasFurtherInput

public boolean hasFurtherInput()

Checks, whether the input that is blocked by this iterator, has further elements available. This method may be used to forecast (for example at the point where a block is full) whether there will be more data (possibly in another block).

Returns:

True, if there will be more data, false otherwise.

close

public void close()

This method closes the iterator and releases all resources. This method works both as a regular shutdown and as a canceling method. The method may be called multiple times and will not produce an error.

open

public void open()

writeNextRecord

protected boolean writeNextRecord(T record)
                           throws IOException

Throws:

IOException

getNextRecord

protected T getNextRecord(T reuse)
                   throws IOException

Throws:

IOException