Class ObjectToFloatMap<K>
- java.lang.Object
-
- org.apache.lucene.util.collections.ObjectToFloatMap<K>
-
public class ObjectToFloatMap<K> extends Object
An Array-based hashtable which maps Objects of generic type T to primitive float values.
The hashtable is constructed with a given capacity, or 16 as a default. In case there's not enough room for new pairs, the hashtable grows.
Capacity is adjusted to a power of 2, and there are 2 * capacity entries for the hash. The pre allocated arrays (for keys, values) are at length of capacity + 1, when index 0 is used as 'Ground' or 'NULL'.
The arrays are allocated ahead of hash operations, and form an 'empty space' list, to which the key,value pair is allocated.- WARNING: This API is experimental and might change in incompatible ways in the next release.
-
-
Constructor Summary
Constructors Constructor Description ObjectToFloatMap()
Constructs a map with default capacity.ObjectToFloatMap(int capacity)
Constructs a map with given capacity.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected int
calcBaseHashIndex(K key)
Calculating the baseHash index using the internalhashFactor
.void
clear()
Empties the map.boolean
containsKey(K key)
Checks if a given key exists in the map.boolean
containsValue(float o)
Checks if the given object exists in the map.
This method iterates over the collection, trying to find an equal object.boolean
equals(Object o)
protected int
find(K key)
Find the actual index of a given key.float
get(K key)
Returns the float mapped with the given key.protected void
grow()
Grows the map.int
hashCode()
boolean
isEmpty()
FloatIterator
iterator()
Returns a new iterator for the mapped floats.Iterator<K>
keyIterator()
Returns an iterator on the map keys.float
put(K key, float e)
Inserts the <key,value> pair into the map.float
remove(K key)
Removes a <key,value> pair from the map and returns the mapped value, orFloat.NaN
if the none existed.int
size()
float[]
toArray()
Translates the mapped pairs' values into an array of Objectsfloat[]
toArray(float[] a)
Translates the mapped pairs' values into an array of TString
toString()
-
-
-
Constructor Detail
-
ObjectToFloatMap
public ObjectToFloatMap()
Constructs a map with default capacity.
-
ObjectToFloatMap
public ObjectToFloatMap(int capacity)
Constructs a map with given capacity. Capacity is adjusted to a native power of 2, with minimum of 16.- Parameters:
capacity
- minimum capacity for the map.
-
-
Method Detail
-
calcBaseHashIndex
protected int calcBaseHashIndex(K key)
Calculating the baseHash index using the internalhashFactor
.- Parameters:
key
-
-
clear
public void clear()
Empties the map. Generates the "Empty" space list for later allocation.
-
containsKey
public boolean containsKey(K key)
Checks if a given key exists in the map.- Parameters:
key
- that is checked against the map data.- Returns:
- true if the key exists in the map. false otherwise.
-
containsValue
public boolean containsValue(float o)
Checks if the given object exists in the map.
This method iterates over the collection, trying to find an equal object.- Parameters:
o
- object that is checked against the map data.- Returns:
- true if the object exists in the map (in .equals() meaning). false otherwise.
-
find
protected int find(K key)
Find the actual index of a given key.- Parameters:
key
-- Returns:
- index of the key. zero if the key wasn't found.
-
get
public float get(K key)
Returns the float mapped with the given key.- Parameters:
key
- object who's mapped float we're interested in.- Returns:
- a float mapped by the given key. Float.NaN if the key wasn't found.
-
grow
protected void grow()
Grows the map. Allocates a new map of double the capacity, and fast-insert the old key-value pairs.
-
isEmpty
public boolean isEmpty()
- Returns:
- true if the map is empty. false otherwise.
-
iterator
public FloatIterator iterator()
Returns a new iterator for the mapped floats.
-
put
public float put(K key, float e)
Inserts the <key,value> pair into the map. If the key already exists, this method updates the mapped value to the given one, returning the old mapped value.- Returns:
- the old mapped value, or
Float.NaN
if the key didn't exist.
-
remove
public float remove(K key)
Removes a <key,value> pair from the map and returns the mapped value, orFloat.NaN
if the none existed.- Parameters:
key
- used to find the value to remove- Returns:
- the removed value or
Float.NaN
if none existed.
-
size
public int size()
- Returns:
- number of pairs currently in the map
-
toArray
public float[] toArray()
Translates the mapped pairs' values into an array of Objects- Returns:
- an object array of all the values currently in the map.
-
toArray
public float[] toArray(float[] a)
Translates the mapped pairs' values into an array of T- Parameters:
a
- the array into which the elements of the list are to be stored, if it is big enough; otherwise, use as much space as it can.- Returns:
- an array containing the elements of the list
-
-