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/*
Jazzy - a Java library for Spell Checking
Copyright (C) 2001 Mindaugas Idzelis
Full text of license can be found in LICENSE.txt
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package com.swabunga.spell.engine;
import java.io.EOFException;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.LinkedList;
import java.util.List;
/**
* Another implementation of SpellDictionary that doesn't cache any
* words in memory. Avoids the huge footprint of
* SpellDictionaryHashMap 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 implementation requires a special dictionary file, with "code*word"
* lines sorted by code. It's using a dichotomy algorithm to search for words in
* the dictionary
*
* @author Damien Guillaume
* @version 0.1
*/
public class SpellDictionaryDichoDisk extends SpellDictionaryASpell {
/** Holds the dictionary file for reading */
private RandomAccessFile dictFile = null;
/** dictionary and phonetic file encoding */
private String encoding = null;
/**
* Dictionary convenience Constructor.
*
* @param wordList The file containing the words list for the dictionary
* @throws java.io.FileNotFoundException indicates problems locating the
* words list file on the system
* @throws java.io.IOException indicates problems reading the words list
* file
*/
public SpellDictionaryDichoDisk(File wordList)
throws FileNotFoundException, IOException {
super((File) null);
dictFile = new RandomAccessFile(wordList, "r");
}
/**
* Dictionary convenience Constructor.
*
* @param wordList The file containing the words list for the dictionary
* @param encoding Uses the character set encoding specified
* @throws java.io.FileNotFoundException indicates problems locating the
* words list file on the system
* @throws java.io.IOException indicates problems reading the words list
* file
*/
public SpellDictionaryDichoDisk(File wordList, String encoding)
throws FileNotFoundException, IOException {
super((File) null);
this.encoding = encoding;
dictFile = new RandomAccessFile(wordList, "r");
}
/**
* Dictionary constructor that uses an aspell phonetic file to build the
* transformation table.
*
* @param wordList The file containing the words list for the dictionary
* @param phonetic The file to use for phonetic transformation of the
* wordlist.
* @throws java.io.FileNotFoundException indicates problems locating the
* file on the system
* @throws java.io.IOException indicates problems reading the words list
* file
*/
public SpellDictionaryDichoDisk(File wordList, File phonetic)
throws FileNotFoundException, IOException {
super(phonetic);
dictFile = new RandomAccessFile(wordList, "r");
}
/**
* Dictionary constructor that uses an aspell phonetic file to build the
* transformation table.
*
* @param wordList The file containing the words list for the dictionary
* @param phonetic The file to use for phonetic transformation of the
* wordlist.
* @param encoding Uses the character set encoding specified
* @throws java.io.FileNotFoundException indicates problems locating the
* file on the system
* @throws java.io.IOException indicates problems reading the words list
* file
*/
public SpellDictionaryDichoDisk(File wordList, File phonetic,
String encoding) throws FileNotFoundException, IOException {
super(phonetic, encoding);
this.encoding = encoding;
dictFile = new RandomAccessFile(wordList, "r");
}
/**
* Add a word permanently to the dictionary (and the dictionary file).
* not implemented !
*
* @param word The word to add.
*/
public void addWord(String word) {
System.err
.println("error: addWord is not implemented for SpellDictionaryDichoDisk");
}
/**
* Search the dictionary file for the words corresponding to the code within
* positions p1 - p2
*/
private List dichoFind(String code, long p1, long p2)
throws IOException {
// System.out.println("dichoFind("+code+","+p1+","+p2+")");
long pm = (p1 + p2) / 2;
dictFile.seek(pm);
String l;
if (encoding == null)
l = dictFile.readLine();
else
l = dictReadLine();
pm = dictFile.getFilePointer();
if (encoding == null)
l = dictFile.readLine();
else
l = dictReadLine();
long pm2 = dictFile.getFilePointer();
if (pm2 >= p2)
return (seqFind(code, p1, p2));
int istar = l.indexOf('*');
if (istar == -1)
throw new IOException("bad format: no * !");
String testcode = l.substring(0, istar);
int comp = code.compareTo(testcode);
if (comp < 0)
return (dichoFind(code, p1, pm - 1));
else if (comp > 0)
return (dichoFind(code, pm2, p2));
else {
List l1 = dichoFind(code, p1, pm - 1);
List l2 = dichoFind(code, pm2, p2);
String word = l.substring(istar + 1);
l1.add(word);
l1.addAll(l2);
return (l1);
}
}
private List seqFind(String code, long p1, long p2)
throws IOException {
// System.out.println("seqFind("+code+","+p1+","+p2+")");
List list = new LinkedList();
dictFile.seek(p1);
while (dictFile.getFilePointer() < p2) {
String l;
if (encoding == null)
l = dictFile.readLine();
else
l = dictReadLine();
int istar = l.indexOf('*');
if (istar == -1)
throw new IOException("bad format: no * !");
String testcode = l.substring(0, istar);
if (testcode.equals(code)) {
String word = l.substring(istar + 1);
list.add(word);
}
}
return (list);
}
/**
* Read a line of dictFile with a specific encoding
*/
private String dictReadLine() throws IOException {
int max = 255;
byte b = 0;
byte[] buf = new byte[max];
int i = 0;
try {
for (; b != '\n' && b != '\r' && i < max - 1; i++) {
b = dictFile.readByte();
buf[i] = b;
}
} catch (EOFException ex) {
}
if (i == 0)
return ("");
String s = new String(buf, 0, i - 1, encoding);
return (s);
}
/**
* Returns a list of strings (words) for the code.
*
* @param code The phonetic code common to the list of words
* @return A list of words having the same phonetic code
*/
public List getWords(String code) {
// System.out.println("getWords("+code+")");
List list;
try {
list = dichoFind(code, 0, dictFile.length() - 1);
// System.out.println(list);
} catch (IOException ex) {
System.err.println("IOException: " + ex.getMessage());
list = new LinkedList();
}
return list;
}
}