com.hankcs.algorithm

Class AhoCorasickDoubleArrayTrie<V>

java.lang.Object

com.hankcs.algorithm.AhoCorasickDoubleArrayTrie<V>

All Implemented Interfaces:

Serializable

public class AhoCorasickDoubleArrayTrie<V>
extends Object
implements Serializable

An implementation of Aho Corasick algorithm based on Double Array Trie

Author:

hankcs

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AhoCorasickDoubleArrayTrie.Hit<V> A result output
static interface	AhoCorasickDoubleArrayTrie.IHit<V> Processor handles the output when hit a keyword
static interface	AhoCorasickDoubleArrayTrie.IHitCancellable<V> Callback that allows to cancel the search process.
static interface	AhoCorasickDoubleArrayTrie.IHitFull<V> Processor handles the output when hit a keyword, with more detail

Field Summary

Fields

Modifier and Type	Field and Description
protected int[]	base base array of the Double Array Trie structure
protected int[]	check check array of the Double Array Trie structure
protected int[]	fail fail table of the Aho Corasick automata
protected int[]	l the length of every key
protected int[][]	output output table of the Aho Corasick automata
protected int	size the size of base and check array
protected V[]	v outer value array

Constructor Summary

Constructors

Constructor and Description
AhoCorasickDoubleArrayTrie()

Method Summary

Modifier and Type	Method and Description
void	build(Map<String,V> map) Build a AhoCorasickDoubleArrayTrie from a map
int	exactMatchSearch(String key) match exactly by a key
AhoCorasickDoubleArrayTrie.Hit<V>	findFirst(String text) Search first match in string
V	get(int index) Pick the value by index in value array Notice that to be more efficiently, this method DO NOT check the parameter
V	get(String key) Get value by a String key, just like a map.get() method
void	load(ObjectInputStream in) Load data from [ObjectInputStream]
boolean	matches(String text) Checks that string contains at least one substring
void	parseText(char[] text, AhoCorasickDoubleArrayTrie.IHit<V> processor) Parse text
void	parseText(char[] text, AhoCorasickDoubleArrayTrie.IHitFull<V> processor) Parse text
List<AhoCorasickDoubleArrayTrie.Hit<V>>	parseText(CharSequence text) Parse text
void	parseText(CharSequence text, AhoCorasickDoubleArrayTrie.IHit<V> processor) Parse text
void	parseText(CharSequence text, AhoCorasickDoubleArrayTrie.IHitCancellable<V> processor) Parse text
void	save(ObjectOutputStream out) Save
boolean	set(String key, V value) Update a value corresponding to a key
int	size()
protected int	transition(int current, char c) transition of a state
protected int	transitionWithRoot(int nodePos, char c) transition of a state, if the state is root and it failed, then returns the root

Methods inherited from class java.lang.Object

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

Field Detail

check

protected int[] check

check array of the Double Array Trie structure

base

protected int[] base

base array of the Double Array Trie structure

fail

protected int[] fail

fail table of the Aho Corasick automata

output

protected int[][] output

output table of the Aho Corasick automata

v

protected V[] v

outer value array

l

protected int[] l

the length of every key

size

protected int size

the size of base and check array

Constructor Detail

AhoCorasickDoubleArrayTrie

public AhoCorasickDoubleArrayTrie()

Method Detail

parseText

public List<AhoCorasickDoubleArrayTrie.Hit<V>> parseText(CharSequence text)

Parse text

Parameters:

text - The text

Returns:

a list of outputs

parseText

public void parseText(CharSequence text,
                      AhoCorasickDoubleArrayTrie.IHit<V> processor)

Parse text

Parameters:

text - The text

processor - A processor which handles the output

parseText

public void parseText(CharSequence text,
                      AhoCorasickDoubleArrayTrie.IHitCancellable<V> processor)

Parse text

Parameters:

text - The text

processor - A processor which handles the output

parseText

public void parseText(char[] text,
                      AhoCorasickDoubleArrayTrie.IHit<V> processor)

Parse text

Parameters:

text - The text

processor - A processor which handles the output

parseText

public void parseText(char[] text,
                      AhoCorasickDoubleArrayTrie.IHitFull<V> processor)

Parse text

Parameters:

text - The text

processor - A processor which handles the output

matches

public boolean matches(String text)

Checks that string contains at least one substring

Parameters:

text - source text to check

Returns:

true if string contains at least one substring

findFirst

public AhoCorasickDoubleArrayTrie.Hit<V> findFirst(String text)

Search first match in string

Parameters:

text - source text to check

Returns:

first match or null if there are no matches

save

public void save(ObjectOutputStream out)
          throws IOException

Save

Parameters:

out - An ObjectOutputStream object

Throws:

IOException - Some IOException

load

public void load(ObjectInputStream in)
          throws IOException,
                 ClassNotFoundException

Load data from [ObjectInputStream]

Parameters:

in - An ObjectInputStream object

Throws:

IOException - If can't read the file from path

ClassNotFoundException - If the class doesn't exist or matched

get

public V get(String key)

Get value by a String key, just like a map.get() method

Parameters:

key - The key

Returns:

value if exist otherwise it return null

set

public boolean set(String key,
                   V value)

Update a value corresponding to a key

Parameters:

key - the key

value - the value

Returns:

successful or not（failure if there is no key）

get

public V get(int index)

Pick the value by index in value array
Notice that to be more efficiently, this method DO NOT check the parameter

Parameters:

index - The index

Returns:

The value

transition

protected int transition(int current,
                         char c)

transition of a state

Parameters:

current -

c -

Returns:

transitionWithRoot

protected int transitionWithRoot(int nodePos,
                                 char c)

transition of a state, if the state is root and it failed, then returns the root

Parameters:

nodePos -

c -

Returns:

build

public void build(Map<String,V> map)

Build a AhoCorasickDoubleArrayTrie from a map

Parameters:

map - a map containing key-value pairs

exactMatchSearch

public int exactMatchSearch(String key)

match exactly by a key

Parameters:

key - the key

Returns:

the index of the key, you can use it as a perfect hash function

size

public int size()

Returns:

the size of the keywords