Class IntToDoubleMap
- java.lang.Object
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- org.apache.lucene.util.collections.IntToDoubleMap
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public class IntToDoubleMap extends Object
An Array-based hashtable which maps primitive int to a primitive double.
The hashtable is constracted 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.
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Field Summary
Fields Modifier and Type Field Description static double
GROUND
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Constructor Summary
Constructors Constructor Description IntToDoubleMap()
Constructs a map with default capacity.IntToDoubleMap(int capacity)
Constructs a map with given capacity.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected int
calcBaseHashIndex(int key)
Calculating the baseHash index using the internalhashFactor
.void
clear()
Empties the map.boolean
containsKey(int key)
Checks if a given key exists in the map.boolean
containsValue(double value)
Checks if the given value exists in the map.
This method iterates over the collection, trying to find an equal object.boolean
equals(Object o)
protected int
find(int key)
Find the actual index of a given key.double
get(int key)
Returns the value mapped with the given key.protected void
grow()
Grows the map.int
hashCode()
boolean
isEmpty()
DoubleIterator
iterator()
Returns a new iterator for the mapped double values.IntIterator
keyIterator()
Returns an iterator on the map keys.double
put(int key, double v)
Inserts the <key,value> pair into the map.double
remove(int key)
Removes a <key,value> pair from the map and returns the mapped value, orDouble.NaN
if the none existed.int
size()
double[]
toArray()
Translates the mapped pairs' values into an array of Objectsdouble[]
toArray(double[] a)
Translates the mapped pairs' values into an array of TString
toString()
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Field Detail
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GROUND
public static final double GROUND
- See Also:
- Constant Field Values
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Constructor Detail
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IntToDoubleMap
public IntToDoubleMap()
Constructs a map with default capacity.
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IntToDoubleMap
public IntToDoubleMap(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.
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Method Detail
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calcBaseHashIndex
protected int calcBaseHashIndex(int key)
Calculating the baseHash index using the internalhashFactor
.- Parameters:
key
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clear
public void clear()
Empties the map. Generates the "Empty" space list for later allocation.
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containsKey
public boolean containsKey(int 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.
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containsValue
public boolean containsValue(double value)
Checks if the given value exists in the map.
This method iterates over the collection, trying to find an equal object.- Parameters:
value
- double value that is checked against the map data.- Returns:
- true if the value exists in the map, false otherwise.
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find
protected int find(int key)
Find the actual index of a given key.- Parameters:
key
-- Returns:
- index of the key. zero if the key wasn't found.
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get
public double get(int key)
Returns the value mapped with the given key.- Parameters:
key
- int who's mapped object we're interested in.- Returns:
- a double value mapped by the given key. Double.NaN if the key wasn't found.
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grow
protected void grow()
Grows the map. Allocates a new map of double the capacity, and fast-insert the old key-value pairs.
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isEmpty
public boolean isEmpty()
- Returns:
- true if the map is empty. false otherwise.
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iterator
public DoubleIterator iterator()
Returns a new iterator for the mapped double values.
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keyIterator
public IntIterator keyIterator()
Returns an iterator on the map keys.
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put
public double put(int key, double v)
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
Double.NaN
if the key didn't exist.
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remove
public double remove(int key)
Removes a <key,value> pair from the map and returns the mapped value, orDouble.NaN
if the none existed.- Parameters:
key
- used to find the value to remove- Returns:
- the removed value or
Double.NaN
if none existed.
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size
public int size()
- Returns:
- number of pairs currently in the map
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toArray
public double[] toArray()
Translates the mapped pairs' values into an array of Objects- Returns:
- a double array of all the values currently in the map.
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toArray
public double[] toArray(double[] 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 use whatever space we need, setting the one after the true data asDouble.NaN
.- Returns:
- an array containing the elements of the list, using the given parameter if big enough, otherwise allocate an appropriate array and return it.
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