it.unimi.dsi.fastutil.objects

Class ObjectBigSpliterators.AbstractIndexBasedSpliterator<K>

java.lang.Object

it.unimi.dsi.fastutil.objects.AbstractObjectSpliterator<K>

it.unimi.dsi.fastutil.objects.ObjectBigSpliterators.AbstractIndexBasedSpliterator<K>

All Implemented Interfaces:

it.unimi.dsi.fastutil.objects.ObjectSpliterator<K>, java.util.Spliterator<K>

Direct Known Subclasses:

ObjectBigSpliterators.EarlyBindingSizeIndexBasedSpliterator, ObjectBigSpliterators.LateBindingSizeIndexBasedSpliterator

Enclosing class:

ObjectBigSpliterators

public abstract static class ObjectBigSpliterators.AbstractIndexBasedSpliterator<K>
extends it.unimi.dsi.fastutil.objects.AbstractObjectSpliterator<K>

A skeletal implementation for a spliterator backed by an index based data store. High performance concrete implementations (like the main Spliterator of BigArrayBigList) generally should avoid using this and just implement the interface directly, but should be decent for less performance critical implementations.

As the abstract methods in this class are used in inner loops, it is generally a good idea to override the class as final as to encourage the JVM to inline them (or alternatively, override the abstract methods as final).

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Spliterator

java.util.Spliterator.OfDouble, java.util.Spliterator.OfInt, java.util.Spliterator.OfLong, java.util.Spliterator.OfPrimitive<T,T_CONS,T_SPLITR extends java.util.Spliterator.OfPrimitive<T,T_CONS,T_SPLITR>>

Field Summary

Fields

Modifier and Type	Field and Description
protected long	pos The current position index, the index of the item to be given after the next call to tryAdvance(java.util.function.Consumer<? super K>).

Fields inherited from interface java.util.Spliterator

CONCURRENT, DISTINCT, IMMUTABLE, NONNULL, ORDERED, SIZED, SORTED, SUBSIZED

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractIndexBasedSpliterator(long initialPos)

Method Summary

Modifier and Type	Method and Description
int	characteristics()
protected long	computeSplitPoint() Compute where to split on the next trySplit(), given the current pos and getMaxPos() (or any other metric the implementation wishes to use).
long	estimateSize()
void	forEachRemaining(java.util.function.Consumer<? super K> action)
protected abstract K	get(long location) Get the item corresponding to the given index location.
protected abstract long	getMaxPos() The maximum pos can be, and is the logical end (exclusive) of the "range".
protected abstract it.unimi.dsi.fastutil.objects.ObjectSpliterator<K>	makeForSplit(long pos, long maxPos) Make a new spliterator to trySplit() starting with the given pos and ending at the given maxPos.
long	skip(long n)
boolean	tryAdvance(java.util.function.Consumer<? super K> action)
it.unimi.dsi.fastutil.objects.ObjectSpliterator<K>	trySplit()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Spliterator

getComparator, getExactSizeIfKnown, hasCharacteristics

Field Detail

pos

protected long pos

The current position index, the index of the item to be given after the next call to tryAdvance(java.util.function.Consumer<? super K>).

This value will be between minPos and getMaxPos() (exclusive) (on a best effort, so concurrent structural modifications may cause this to be violated, but that usually invalidates spliterators anyways). Thus pos being minPos + 2 would mean tryAdvance(java.util.function.Consumer<? super K>) was called twice and the next call will give the third element of this spliterator.

Constructor Detail

AbstractIndexBasedSpliterator

protected AbstractIndexBasedSpliterator(long initialPos)

Method Detail

get

protected abstract K get(long location)

Get the item corresponding to the given index location.

Do not advance pos in this method; the default tryAdvance(java.util.function.Consumer<? super K>) and forEachRemaining(java.util.function.Consumer<? super K>) methods takes care of this.

The location given will be between minPos and getMaxPos() (exclusive). Thus, a location of minPos + 2 would mean tryAdvance(java.util.function.Consumer<? super K>) was called twice and this method should return what the next call to #tryAdvance() should give.

getMaxPos

protected abstract long getMaxPos()

The maximum pos can be, and is the logical end (exclusive) of the "range".

If pos is equal to the return of this method, this means the last element has been returned and the next call to tryAdvance(java.util.function.Consumer<? super K>) will return false.

Usually set return the parent collection's size, but does not have to be (for example, sublists and subranges).

This method allows the implementation to decide how it binds on the size (late or early). However, ObjectBigSpliterators.EarlyBindingSizeIndexBasedSpliterator and ObjectBigSpliterators.LateBindingSizeIndexBasedSpliterator give an implementation of this method for the two most common strategies.

makeForSplit

protected abstract it.unimi.dsi.fastutil.objects.ObjectSpliterator<K> makeForSplit(long pos,
                                                                                   long maxPos)

Make a new spliterator to trySplit() starting with the given pos and ending at the given maxPos.

An implementation is free to look at the range given, and if it deems it too small to split further, return null. In which case, trySplit() will not modify the state of this spliterator.

Do not modify pos in this method; the default trySplit() method takes care of this.

To comply with the spec of Spliterator.ORDERED, this will only be called to create prefixes of the current sequence this spliterator is over, and this instance will start at the end of the returned sequence and have the same end point. As such, this method should also not change what getMaxPos() returns.

computeSplitPoint

protected long computeSplitPoint()

Compute where to split on the next trySplit(), given the current pos and getMaxPos() (or any other metric the implementation wishes to use).

If a value == pos or == getMaxPos() is returned, the trySplit() method will assume a split of size 0 was computed, and thus won't split or change state. If a value outside that range is returned, then trySplit() will throw IndexOutOfBoundsException. In particular, this means that no handling of overflow or underflow is performed.

characteristics

public int characteristics()

estimateSize

public long estimateSize()

tryAdvance

public boolean tryAdvance(java.util.function.Consumer<? super K> action)

forEachRemaining

public void forEachRemaining(java.util.function.Consumer<? super K> action)

skip

public long skip(long n)

trySplit

public it.unimi.dsi.fastutil.objects.ObjectSpliterator<K> trySplit()

Throws:

java.lang.IndexOutOfBoundsException - if the return of computeSplitPoint() was < pos or > {@link #getMaxPos()}.