Package org.predict4all.nlp.ngram.trie

Class StaticNGramTrieNode

java.lang.Object

org.predict4all.nlp.ngram.trie.AbstractNGramTrieNode<StaticNGramTrieNode>

org.predict4all.nlp.ngram.trie.StaticNGramTrieNode

public class StaticNGramTrieNode
extends AbstractNGramTrieNode<StaticNGramTrieNode>

Represent a static ngram trie node : when node are used only to retrieve information and compute probabilities, but children are never updated.
This node is particular because children node are loaded on demand from a FileChannel.
This node is produced in a read only version : to create this node, DynamicNGramTrieNode and TrainingNGramDictionary should be used.

Field Summary

Fields inherited from class org.predict4all.nlp.ngram.trie.AbstractNGramTrieNode

children, childrenBackoffWeight, childrenPosition, DYNAMIC_TRIE_NODE_SIZE_BYTE, frequency, STATIC_TRIE_NODE_SIZE_BYTE

Constructor Summary

Constructors

Constructor	Description
StaticNGramTrieNode()

Method Summary

Modifier and Type	Method	Description
boolean	checkChildrenLoading(java.nio.channels.FileChannel fileChannel)	Check that children for this node are loaded. If not, try to load children from the given fileChannel.
int	getChildrenSize()
StaticNGramTrieNode	getNodeFor(java.nio.channels.FileChannel fileChannel, int[] prefix, int index)	Will try to retrieve a node for a given prefix. Load needed node on demand while browsing the trie. Children of the returned node are not loaded yet.
int	readNodeInformation(java.nio.ByteBuffer buffWrite)	Read the node information contained into the given buffer to this node (without any check).

Methods inherited from class org.predict4all.nlp.ngram.trie.AbstractNGramTrieNode

compact, getChildren, getChildrenBackoffWeight, getFrequency

Methods inherited from class java.lang.Object

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

Constructor Detail

StaticNGramTrieNode

public StaticNGramTrieNode()

Method Detail

getNodeFor

public StaticNGramTrieNode getNodeFor(java.nio.channels.FileChannel fileChannel,
                                      int[] prefix,
                                      int index)
                               throws java.io.IOException

Will try to retrieve a node for a given prefix.
Load needed node on demand while browsing the trie.
Children of the returned node are not loaded yet.

Parameters:

fileChannel - the file channel containing the trie structure.

prefix - ngram prefix

index - index in prefix (0 = full prefix)

Returns:

the node found for the given prefix (or null if the trie doesn't contains any node for the given prefix)

Throws:

java.io.IOException - if children can't be read for a node

checkChildrenLoading

public boolean checkChildrenLoading(java.nio.channels.FileChannel fileChannel)
                             throws java.io.IOException

Check that children for this node are loaded.
If not, try to load children from the given fileChannel.

Parameters:

fileChannel - file channel containing the trie structure.

Returns:

true if there is children and children are loaded.

Throws:

java.io.IOException - if there is children, but they can't be loaded

readNodeInformation

public int readNodeInformation(java.nio.ByteBuffer buffWrite)

Read the node information contained into the given buffer to this node (without any check).

Parameters:

buffWrite - the buffer containing node information.

Returns:

this node word id (read from buffer)

getChildrenSize

public int getChildrenSize()

Specified by:

getChildrenSize in class AbstractNGramTrieNode<StaticNGramTrieNode>

Returns:

the different children count (not the total children count)