opennlp.tools.ml.model

Class IndexHashTable<T>

java.lang.Object

opennlp.tools.ml.model.IndexHashTable<T>

public class IndexHashTable<T>
extends Object

The IndexHashTable is a hash table which maps entries of an array to their index in the array. All entries in the array must be unique otherwise a well-defined mapping is not possible.

The entry objects must implement Object.equals(Object) and Object.hashCode() otherwise the behavior of this class is undefined.

The implementation uses a hash table with open addressing and linear probing.

The table is thread safe and can concurrently accessed by multiple threads, thread safety is achieved through immutability. Though its not strictly immutable which means, that the table must still be safely published to other threads.

Constructor Summary

Constructors

Constructor and Description
IndexHashTable(T[] mapping, double loadfactor) Initializes the current instance.

Method Summary

Methods

Modifier and Type	Method and Description
int	get(T key) Retrieves the index for the specified key.
int	size() Retrieves the size.
T[]	toArray(T[] array)

Methods inherited from class java.lang.Object

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

Constructor Detail

IndexHashTable

public IndexHashTable(T[] mapping,
              double loadfactor)

Initializes the current instance. The specified array is copied into the table and later changes to the array do not affect this table in any way.

Parameters:

mapping - the values to be indexed, all values must be unique otherwise a well-defined mapping of an entry to an index is not possible

loadfactor - the load factor, usually 0.7

Throws:

IllegalArgumentException - if the entries are not unique

Method Detail

get

public int get(T key)

Retrieves the index for the specified key.

Parameters:

key -

Returns:

the index or -1 if there is no entry to the keys

size

public int size()

Retrieves the size.

Returns:

the number of elements in this map.

toArray

public T[] toArray(T[] array)