Package org.apache.hadoop.util

Class LightWeightResizableGSet<K,E extends K>

java.lang.Object

org.apache.hadoop.util.LightWeightGSet<K,E>

org.apache.hadoop.util.LightWeightResizableGSet<K,E>

Type Parameters:

K - Key type for looking up the elements

E - Element type, which must be (1) a subclass of K, and (2) implementing LightWeightGSet.LinkedElement interface.

All Implemented Interfaces:

java.lang.Iterable<E>, GSet<K,E>

@Private
public class LightWeightResizableGSet<K,E extends K>
extends LightWeightGSet<K,E>

A low memory footprint GSet implementation, which uses an array for storing the elements and linked lists for collision resolution. If the size of elements exceeds the threshold, the internal array will be resized to double length. This class does not support null element. This class is thread safe.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.util.LightWeightGSet

LightWeightGSet.LinkedElement, LightWeightGSet.SetIterator

Field Summary

Fields inherited from class org.apache.hadoop.util.LightWeightGSet

entries, hash_mask, modification, size

Fields inherited from interface org.apache.hadoop.util.GSet

LOG

Constructor Summary

Constructors

Constructor	Description
LightWeightResizableGSet()
LightWeightResizableGSet(int initCapacity)
LightWeightResizableGSet(int initCapacity, float loadFactor)

Method Summary

Modifier and Type	Method	Description
protected void	expandIfNecessary()	Checks if we need to expand, and expands if necessary.
E	get(K key)	Return the stored element which is equal to the given key.
void	getIterator(java.util.function.Consumer<java.util.Iterator<E>> consumer)
E	put(E element)	Add/replace an element.
E	remove(K key)	Remove the element corresponding to the given key.
protected void	resize(int cap)	Resize the internal table to given capacity.
int	size()

Methods inherited from class org.apache.hadoop.util.LightWeightGSet

actualArrayLength, clear, computeCapacity, contains, convert, getIndex, iterator, printDetails, remove, toString, values

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

LightWeightResizableGSet

public LightWeightResizableGSet(int initCapacity,
                                float loadFactor)

LightWeightResizableGSet

public LightWeightResizableGSet()

LightWeightResizableGSet

public LightWeightResizableGSet(int initCapacity)

Method Detail

put

public E put(E element)

Description copied from interface: GSet

Add/replace an element. If the element does not exist, add it to the set. Otherwise, replace the existing element. Note that this operation is similar to Map.put(Object, Object) but is different from Set.add(Object) which does not replace the existing element if there is any.

Specified by:

put in interface GSet<K,E extends K>

Overrides:

put in class LightWeightGSet<K,E extends K>

Parameters:

element - The element being put.

Returns:

the previous stored element if there is any. Otherwise, return null.

get

public E get(K key)

Description copied from interface: GSet

Return the stored element which is equal to the given key. This operation is similar to Map.get(Object).

Specified by:

get in interface GSet<K,E extends K>

Overrides:

get in class LightWeightGSet<K,E extends K>

Parameters:

key - The given key.

Returns:

The stored element if it exists. Otherwise, return null.

remove

public E remove(K key)

Description copied from interface: GSet

Remove the element corresponding to the given key. This operation is similar to Map.remove(Object).

Specified by:

remove in interface GSet<K,E extends K>

Overrides:

remove in class LightWeightGSet<K,E extends K>

Parameters:

key - The key of the element being removed.

Returns:

If such element exists, return it. Otherwise, return null.

size

public int size()

Specified by:

size in interface GSet<K,E extends K>

Overrides:

size in class LightWeightGSet<K,E extends K>

Returns:

The size of this set.

getIterator

public void getIterator(java.util.function.Consumer<java.util.Iterator<E>> consumer)

resize

protected void resize(int cap)

Resize the internal table to given capacity.

Parameters:

cap - capacity.

expandIfNecessary

protected void expandIfNecessary()

Checks if we need to expand, and expands if necessary.