Package it.unimi.dsi.util

Class ByteBufferLongBigList

java.lang.Object

java.util.AbstractCollection<Long>

it.unimi.dsi.fastutil.longs.AbstractLongCollection

it.unimi.dsi.fastutil.longs.AbstractLongBigList

it.unimi.dsi.util.ByteBufferLongBigList

All Implemented Interfaces:

BigList<Long>, LongBigList, LongCollection, LongIterable, LongStack, Size64, Stack<Long>, FlyweightPrototype<ByteBufferLongBigList>, Comparable<BigList<? extends Long>>, Iterable<Long>, Collection<Long>

public class ByteBufferLongBigList
extends AbstractLongBigList
implements FlyweightPrototype<ByteBufferLongBigList>

A bridge between byte buffers and long big lists.

Java's memory-mapping facilities have the severe limitation of mapping at most Integer.MAX_VALUE bytes, as they expose the content of a file using a MappedByteBuffer. This class can expose a file of longs of arbitrary length as a LongBigList that is actually based on an array of MappedByteBuffers, each mapping a chunk of CHUNK_SIZE longs.

Instances of this class are not thread safe, but the copy() method provides a lightweight duplicate that can be accessed independently by another thread. Only chunks that are actually used will be duplicated lazily.

Author:

Sebastiano Vigna

Nested Class Summary

Nested classes/interfaces inherited from class it.unimi.dsi.fastutil.longs.AbstractLongBigList

AbstractLongBigList.LongSubList

Field Summary

Fields

Modifier and Type	Field	Description
static long	CHUNK_SIZE	The size in longs of a chunk created by map(FileChannel, ByteOrder, FileChannel.MapMode).

Constructor Summary

Constructors

Modifier	Constructor	Description
	ByteBufferLongBigList(ByteBuffer byteBuffer)	Creates a new byte-buffer long big list from a single ByteBuffer.
protected	ByteBufferLongBigList(ByteBuffer[] byteBuffer, long size, boolean[] readyToUse)	Creates a new byte-buffer long big list.

Method Summary

Modifier and Type	Method	Description
ByteBufferLongBigList	copy()	Returns a copy of this object, sharing state with this object as much as possible.
long	getLong(long index)
static ByteBufferLongBigList	map(FileChannel fileChannel)	Creates a new byte-buffer long big list by read-only mapping a given file channel using the standard Java (i.e., DataOutput) byte order (ByteOrder.BIG_ENDIAN).
static ByteBufferLongBigList	map(FileChannel fileChannel, ByteOrder byteOrder)	Creates a new byte-buffer long big list by read-only mapping a given file channel.
static ByteBufferLongBigList	map(FileChannel fileChannel, ByteOrder byteOrder, FileChannel.MapMode mapMode)	Creates a new byte-buffer long big list by mapping a given file channel.
long	set(long index, long value)
long	size64()

Methods inherited from class it.unimi.dsi.fastutil.longs.AbstractLongBigList

add, add, add, addAll, addAll, addAll, addAll, addAll, addAll, addElements, addElements, clear, compareTo, contains, ensureIndex, ensureRestrictedIndex, equals, get, getElements, hashCode, indexOf, indexOf, iterator, lastIndexOf, lastIndexOf, listIterator, listIterator, peek, peekLong, pop, popLong, push, push, rem, remove, removeElements, removeLong, set, size, size, subList, top, topLong, toString

Methods inherited from class it.unimi.dsi.fastutil.longs.AbstractLongCollection

add, contains, containsAll, remove, removeAll, retainAll, toArray, toLongArray, toLongArray

Methods inherited from class java.util.AbstractCollection

containsAll, isEmpty, removeAll, retainAll, toArray, toArray

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

containsAll, isEmpty, parallelStream, removeAll, retainAll, spliterator, stream, toArray, toArray, toArray

Methods inherited from interface it.unimi.dsi.fastutil.longs.LongCollection

add, contains, containsAll, remove, removeAll, removeIf, removeIf, retainAll, toArray, toLongArray, toLongArray

Methods inherited from interface it.unimi.dsi.fastutil.longs.LongIterable

forEach, forEach

Methods inherited from interface it.unimi.dsi.fastutil.Stack

isEmpty

Field Detail

CHUNK_SIZE

public static final long CHUNK_SIZE

The size in longs of a chunk created by map(FileChannel, ByteOrder, FileChannel.MapMode).

Constructor Detail

ByteBufferLongBigList

public ByteBufferLongBigList(ByteBuffer byteBuffer)

Creates a new byte-buffer long big list from a single ByteBuffer.

Parameters:

byteBuffer - the underlying byte buffer.

ByteBufferLongBigList

protected ByteBufferLongBigList(ByteBuffer[] byteBuffer,
                                long size,
                                boolean[] readyToUse)

Creates a new byte-buffer long big list.

Parameters:

byteBuffer - the underlying byte buffers.

size - the overall number of longs in the underlying byte buffers (i.e., the sum of the capacities of the byte buffers divided by eight).

readyToUse - an array parallel to byteBuffer specifying which buffers do not need to be duplicated before being used (the process will happen lazily); the array will be used internally by the newly created byte-buffer long big list.

Method Detail

map

public static ByteBufferLongBigList map(FileChannel fileChannel)
                                 throws IOException

Creates a new byte-buffer long big list by read-only mapping a given file channel using the standard Java (i.e., DataOutput) byte order (ByteOrder.BIG_ENDIAN).

Parameters:

fileChannel - the file channel that will be mapped.

Returns:

a new read-only byte-buffer long big list over the contents of fileChannel.

Throws:

IOException

See Also:

map(FileChannel, ByteOrder, MapMode)

map

public static ByteBufferLongBigList map(FileChannel fileChannel,
                                        ByteOrder byteOrder)
                                 throws IOException

Creates a new byte-buffer long big list by read-only mapping a given file channel.

Parameters:

fileChannel - the file channel that will be mapped.

byteOrder - a prescribed byte order.

Returns:

a new read-only byte-buffer long big list over the contents of fileChannel.

Throws:

IOException

See Also:

map(FileChannel, ByteOrder, MapMode)

map

public static ByteBufferLongBigList map(FileChannel fileChannel,
                                        ByteOrder byteOrder,
                                        FileChannel.MapMode mapMode)
                                 throws IOException

Creates a new byte-buffer long big list by mapping a given file channel.

Parameters:

fileChannel - the file channel that will be mapped.

byteOrder - a prescribed byte order.

mapMode - the mapping mode: usually FileChannel.MapMode.READ_ONLY, but if intend to make the list mutable, you have to pass FileChannel.MapMode.READ_WRITE.

Returns:

a new byte-buffer long big list over the contents of fileChannel.

Throws:

IOException

copy

public ByteBufferLongBigList copy()

Description copied from interface: FlyweightPrototype

Returns a copy of this object, sharing state with this object as much as possible.

Specified by:

copy in interface FlyweightPrototype<ByteBufferLongBigList>

Returns:

a copy of this object, sharing state with this object as much as possible.

getLong

public long getLong(long index)

Specified by:

getLong in interface LongBigList

set

public long set(long index,
                long value)

Specified by:

set in interface LongBigList

Overrides:

set in class AbstractLongBigList

size64

public long size64()

Specified by:

size64 in interface Size64