org.apache.hadoop.hdfs.util

类 LightWeightGSet<K,E extends K>

java.lang.Object

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

类型参数:

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.

所有已实现的接口:

Iterable<E>, GSet<K,E>

public class LightWeightGSet<K,E extends K>
extends Object
implements GSet<K,E>

A low memory footprint GSet implementation, which uses an array for storing the elements and linked lists for collision resolution. No rehash will be performed. Therefore, the internal array will never be resized. This class does not support null element. This class is not thread safe.

嵌套类概要

嵌套类

限定符和类型	类和说明
static interface	LightWeightGSet.LinkedElement Elements of LightWeightGSet.

字段概要

字段

限定符和类型	字段和说明
static org.apache.commons.logging.Log	LOG

构造器概要

构造器

构造器和说明
LightWeightGSet(int recommended_length)

方法概要

方法

限定符和类型	方法和说明
void	clear()
static int	computeCapacity(double percentage, String mapName) Let t = percentage of max memory.
boolean	contains(K key) Does this set contain an element corresponding to the given key?
E	get(K key) Return the stored element which is equal to the given key.
Iterator<E>	iterator()
void	printDetails(PrintStream out) Print detailed information of this object.
E	put(E element) Add/replace an element.
E	remove(K key) Remove the element corresponding to the given key.
int	size()
String	toString()

从类继承的方法 java.lang.Object

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

字段详细资料

LOG

public static final org.apache.commons.logging.Log LOG

构造器详细资料

LightWeightGSet

public LightWeightGSet(int recommended_length)

参数:

recommended_length - Recommended size of the internal array.

方法详细资料

size

public int size()

指定者:

size 在接口中 GSet<K,E extends K>

返回:

The size of this set.

get

public E get(K key)

从接口复制的说明: GSet

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

指定者:

get 在接口中 GSet<K,E extends K>

参数:

key - The given key.

返回:

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

contains

public boolean contains(K key)

从接口复制的说明: GSet

Does this set contain an element corresponding to the given key?

指定者:

contains 在接口中 GSet<K,E extends K>

参数:

key - The given key.

返回:

true if the given key equals to a stored element. Otherwise, return false.

put

public E put(E element)

从接口复制的说明: 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.

指定者:

put 在接口中 GSet<K,E extends K>

参数:

element - The element being put.

返回:

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

remove

public E remove(K key)

从接口复制的说明: GSet

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

指定者:

remove 在接口中 GSet<K,E extends K>

参数:

key - The key of the element being removed.

返回:

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

iterator

public Iterator<E> iterator()

指定者:

iterator 在接口中 Iterable<E extends K>

toString

public String toString()

覆盖:

toString 在类中 Object

printDetails

public void printDetails(PrintStream out)

Print detailed information of this object.

computeCapacity

public static int computeCapacity(double percentage,
                  String mapName)

Let t = percentage of max memory. Let e = round(log_2 t). Then, we choose capacity = 2^e/(size of reference), unless it is outside the close interval [1, 2^30].

clear

public void clear()

指定者:

clear 在接口中 GSet<K,E extends K>