uk.ac.open.crc.mdsc.engine

Class DiskSpellingDictionary

java.lang.Object

uk.ac.open.crc.mdsc.engine.ASpellSpellingDictionary

uk.ac.open.crc.mdsc.engine.DiskSpellingDictionary

All Implemented Interfaces:

SpellingDictionary

public class DiskSpellingDictionary
extends ASpellSpellingDictionary

An implementation of SpellDictionary that doesn't cache any words in memory. Avoids the huge footprint of HashedSpellingDictionary at the cost of relatively minor latency. A future version of this class that implements some caching strategies might be a good idea in the future, if there's any demand for it.

This class makes use of the "classic" Java IO library (java.io). However, it could probably benefit from the new IO APIs (java.nio), or those introduced in Java 8.

Since:

0.5

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	ready A flag indicating if the initial preparation or loading of the on disk dictionary is complete.

Fields inherited from class uk.ac.open.crc.mdsc.engine.ASpellSpellingDictionary

transformator

Constructor Summary

Constructors

Constructor and Description
DiskSpellingDictionary(java.io.File baseDirectory, java.io.File phoneticFile) Construct a spell dictionary on disk.

Method Summary

Modifier and Type	Method and Description
void	addWord(java.lang.String word) Adds another word to the dictionary.
protected void	buildNewDictionaryDatabase() Builds the file words database file and the contents file for the on disk dictionary.
java.util.List<java.lang.String>	getWords(java.lang.String code) Returns a list of words that have the same phonetic code.
boolean	isReady() Indicates if the initial preparation or loading of the on disk dictionary is complete.
protected void	loadIndex() Loads the index file from disk.

Methods inherited from class uk.ac.open.crc.mdsc.engine.ASpellSpellingDictionary

getPhoneticCode, getSuggestions, getSuggestions, isCorrect

Methods inherited from class java.lang.Object

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

Field Detail

ready

protected boolean ready

A flag indicating if the initial preparation or loading of the on disk dictionary is complete.

Constructor Detail

DiskSpellingDictionary

public DiskSpellingDictionary(java.io.File baseDirectory,
                              java.io.File phoneticFile)
                       throws java.io.FileNotFoundException,
                              java.io.IOException

Construct a spell dictionary on disk. The spell dictionary is created from words list(s) contained in file(s). A words list file is a file with one word per line. Words list files are located in a base/words dictionary where base is the path to words dictionary. The on disk spell dictionary is created in base/db dictionary and contains files:

• contents list the words files used for spelling.
• words.db the content of words files organized as a database of words.
• words.idx an index file to the words.db file content.

The contents file has a list of filename, size indicating the name and length of each files in the base/words dictionary. If one of theses files was changed, added or deleted before the call to the constructor, the process of producing new or updated words.db and words.idx files is started again.

The spellchecking process is then worked upon the words.db and words.idx files.

NB: the constructor may take a long time to run while it constructs or loads the dictionaries. The caller should run this constructor in a separate thread to avoid the calling thread being blocked.

NOTE: Do *not* create two instances of this class pointing to the same base unless you are sure that a new dictionary does not have to be created. In the future, some sort of external locking mechanism may be created that handles this scenario gracefully.

Parameters:

baseDirectory - the base directory in which SpellDictionaryDisk can expect to find its necessary files.

phoneticFile - the phonetic file used by the spellchecker.

Throws:

java.io.FileNotFoundException - indicates problems locating the files on the system

java.io.IOException - indicates problems reading the files

Method Detail

buildNewDictionaryDatabase

protected final void buildNewDictionaryDatabase()
                                         throws java.io.FileNotFoundException,
                                                java.io.IOException

Builds the file words database file and the contents file for the on disk dictionary.

Throws:

java.io.FileNotFoundException - if the files cannot be located

java.io.IOException

addWord

public void addWord(java.lang.String word)

Adds another word to the dictionary. This method is not yet implemented for this class.

Parameters:

word - The word to add.

getWords

public java.util.List<java.lang.String> getWords(java.lang.String code)

Returns a list of words that have the same phonetic code.

Specified by:

getWords in class ASpellSpellingDictionary

Parameters:

code - The phonetic code common to the list of words

Returns:

A list of words having the same phonetic code

isReady

public boolean isReady()

Indicates if the initial preparation or loading of the on disk dictionary is complete.

Returns:

the indication that the dictionary initial setup is done.

loadIndex

protected final void loadIndex()
                        throws java.io.IOException

Loads the index file from disk. The index file accelerates word lookup in the dictionary database file.

Throws:

java.io.IOException - if a problem is encountered reading the index file.