/**
* WordCache
* Copyright 2009 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
* first published 01.10.2009 on http://yacy.net
*
* 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 program in the file lgpl21.txt
* If not, see <http://www.gnu.org/licenses/>.
*/
package net.yacy.document;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ConcurrentModificationException;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.zip.GZIPInputStream;
import net.yacy.cora.sorting.OrderedScoreMap;
import net.yacy.kelondro.logging.Log;
import net.yacy.kelondro.util.MemoryControl;
/**
* provide a completion library for the did-you-mean class
*
*/
public class WordCache {
// common word cache
private static final int commonWordsMaxSize = (int) (MemoryControl.available() / 30000); // maximum size of common word cache
private static final int commonWordsMinLength = 5; // words must have that length at minimum
private static OrderedScoreMap<StringBuilder> commonWords = new OrderedScoreMap<StringBuilder>(StringBuilderComparator.CASE_INSENSITIVE_ORDER);
static {
Log.logConfig("WordCache", "commonWordsMaxSize = " + commonWordsMaxSize);
}
// dictionaries
private final File dictionaryPath;
final Map<String, Dictionary> dictionaries;
public static class Dictionary {
private final TreeSet<StringBuilder> dict; // the word dictionary
private final TreeSet<StringBuilder> tcid; // the dictionary of reverse words
public Dictionary(final File file) throws IOException {
this.dict = new TreeSet<StringBuilder>(StringBuilderComparator.CASE_INSENSITIVE_ORDER);
this.tcid = new TreeSet<StringBuilder>(StringBuilderComparator.CASE_INSENSITIVE_ORDER);
InputStream is = new FileInputStream(file);
if (file.getName().endsWith(".gz")) {
is = new GZIPInputStream(is);
}
final BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
String l;
StringBuilder sb;
try {
while ((l = reader.readLine()) != null) {
if (l.isEmpty() || l.charAt(0) == '#') {
continue;
}
l = l.trim().toLowerCase();
if (l.length() < 4) {
continue;
}
sb = new StringBuilder(l);
this.dict.add(sb);
this.tcid.add(reverse(sb));
}
} catch (final IOException e) {
// finish
}
}
/**
* read the dictionary and construct a set of recommendations to a given string
* @param s input value that is used to match recommendations
* @return set that contains all words that start or end with the input value
*/
public Set<StringBuilder> recommend(StringBuilder string) {
final Set<StringBuilder> ret = new HashSet<StringBuilder>();
SortedSet<StringBuilder> t = this.dict.tailSet(string);
for (final StringBuilder r: t) {
if (StringBuilderComparator.CASE_INSENSITIVE_ORDER.startsWith(r, string) && r.length() > string.length()) {
ret.add(r);
} else {
break;
}
}
string = reverse(string);
t = this.tcid.tailSet(string);
for (final StringBuilder r: t) {
if (StringBuilderComparator.CASE_INSENSITIVE_ORDER.startsWith(r, string) && r.length() > string.length()) {
ret.add(reverse(r));
} else {
break;
}
}
return ret;
}
/**
* check if the library contains the given word
* @param s the given word
* @return true if the library contains the word
*/
public boolean contains(final StringBuilder s) {
return this.dict.contains(s);
// if the above case is true then it is also true for this.tcid and vice versa
// that means it does not need to be tested as well
}
/**
* check if the library supports the given word
* A word is supported, if the library contains a word
* that starts or ends with the given word
* @param s the given word
* @return true if the library supports the word
*/
public boolean supports(StringBuilder string) {
SortedSet<StringBuilder> t = this.dict.tailSet(string);
for (final StringBuilder r: t) {
if (StringBuilderComparator.CASE_INSENSITIVE_ORDER.startsWith(string, r)) {
return true;
}
break;
}
string = reverse(string);
t = this.tcid.tailSet(string);
for (final StringBuilder r: t) {
if (StringBuilderComparator.CASE_INSENSITIVE_ORDER.startsWith(string, r)) {
return true;
}
break;
}
return false;
}
/**
* the size of the dictionary
* @return the number of words in the dictionary
*/
public int size() {
return this.dict.size();
}
/**
* a property that is used during the construction of recommendation:
* if the dictionary is too small, then the non-existence of constructed words
* is not relevant for the construction of artificially constructed words
* If this property returns true, all other words must be in the dictionary
* @param minimumWords
* @return
*/
public boolean isRelevant(final int minimumWords) {
return this.dict.size() >= minimumWords;
}
public Set<StringBuilder> getWords() {
return this.dict;
}
}
public Map<String, Dictionary> getDictionaries() {
return this.dictionaries;
}
/**
* create a new dictionary
* This loads all files that ends with '.words'
* The files must have one word per line
* Comment lines may be given and are encoded as line starting with '#'
* @param dictionaryPath path to a directory with library files
*/
public WordCache(final File dictionaryPath) {
this.dictionaryPath = dictionaryPath;
this.dictionaries = new ConcurrentHashMap<String, Dictionary>();
reload();
}
/**
* add a word to the generic dictionary
* @param word
*/
public static void learn(final StringBuilder word) {
if (word == null) {
return;
}
if (word.length() < commonWordsMinLength) {
return;
}
if (MemoryControl.shortStatus()) {
commonWords.clear();
}
commonWords.inc(word);
if (!(commonWords.sizeSmaller(commonWordsMaxSize))) {
commonWords.shrinkToMaxSize(commonWordsMaxSize / 2);
}
}
public static void learn(Set<String> wordset) {
for (String s: wordset) {
learn(new StringBuilder(s));
}
}
/**
* scan the input directory and load all dictionaries (again)
*/
public void reload() {
if (this.dictionaryPath == null || !this.dictionaryPath.exists()) {
return;
}
final String[] files = this.dictionaryPath.list();
for (final String f: files) {
if (f.endsWith(".words")) {
try {
Dictionary dict = new Dictionary(new File(this.dictionaryPath, f));
this.dictionaries.put(f.substring(0, f.length() - 6), dict);
} catch (final IOException e) {
Log.logException(e);
}
}
}
}
private static StringBuilder reverse(final StringBuilder s) {
final StringBuilder sb = new StringBuilder(s.length());
for (int i = s.length() - 1; i >= 0; i--) {
sb.append(s.charAt(i));
}
return sb;
}
/**
* read the dictionary and construct a set of recommendations to a given string
* @param s input value that is used to match recommendations
* @return set that contains all words that start or end with the input value
*/
public Set<StringBuilder> recommend(StringBuilder string) {
Set<StringBuilder> ret = new HashSet<StringBuilder>();
for (Dictionary dict: this.dictionaries.values()) {
ret.addAll(dict.recommend(string));
}
final SortedMap<StringBuilder, AtomicInteger> u = commonWords.tailMap(string);
StringBuilder vv;
try {
for (final Map.Entry<StringBuilder, AtomicInteger> v: u.entrySet()) {
vv = v.getKey();
if (StringBuilderComparator.CASE_INSENSITIVE_ORDER.startsWith(vv, string) && vv.length() > string.length()) {
ret.add(vv);
} else {
break;
}
}
} catch (final ConcurrentModificationException e) {}
return ret;
}
/**
* check if the library contains the given word
* @param s the given word
* @return true if the library contains the word
*/
public boolean contains(final StringBuilder s) {
for (Dictionary dict: this.dictionaries.values()) {
if (dict.contains(s)) {
return true;
}
}
return false;
}
/**
* check if the library supports the given word
* A word is supported, if the library contains a word
* that starts or ends with the given word
* @param s the given word
* @return true if the library supports the word
*/
public boolean supports(StringBuilder string) {
for (Dictionary dict: this.dictionaries.values()) {
if (dict.supports(string)) {
return true;
}
}
return false;
}
/**
* the size of the dictionary
* @return the number of words in the dictionary
*/
public int size() {
int size = 0;
for (Dictionary dict: this.dictionaries.values()) {
size += dict.size();
}
return size;
}
/**
* a property that is used during the construction of recommendation:
* if the dictionary is too small, then the non-existence of constructed words
* is not relevant for the construction of artificially constructed words
* If this property returns true, all other words must be in the dictionary
* @param minimumWords
* @return
*/
public boolean isRelevant(final int minimumWords) {
for (Dictionary dict: this.dictionaries.values()) {
if (dict.isRelevant(minimumWords)) {
return true;
}
}
return false;
}
}