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org.dizitart.no2.internals.NitriteTextIndexingService Maven / Gradle / Ivy
/*
*
* Copyright 2017-2018 Nitrite author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.dizitart.no2.internals;
import org.dizitart.no2.NitriteId;
import org.dizitart.no2.exceptions.FilterException;
import org.dizitart.no2.exceptions.IndexingException;
import org.dizitart.no2.fulltext.TextIndexingService;
import org.dizitart.no2.fulltext.TextTokenizer;
import org.dizitart.no2.store.NitriteMap;
import java.io.IOException;
import java.util.*;
import java.util.concurrent.ConcurrentSkipListSet;
import static org.dizitart.no2.exceptions.ErrorCodes.IE_FAILED_TO_WRITE_FTS_DATA;
import static org.dizitart.no2.exceptions.ErrorCodes.IE_REMOVE_FULL_TEXT_INDEX_FAILED;
import static org.dizitart.no2.exceptions.ErrorMessage.*;
import static org.dizitart.no2.util.IndexUtils.sortByScore;
/**
* @author Anindya Chatterjee.
*/
class NitriteTextIndexingService implements TextIndexingService {
private TextTokenizer tokenizerService;
private IndexMetaService indexMetaService;
private final Object indexLock = new Object();
NitriteTextIndexingService(TextTokenizer textTokenizer, IndexMetaService indexMetaService) {
this.tokenizerService = textTokenizer;
this.indexMetaService = indexMetaService;
}
@Override
public void createIndex(NitriteId id, String field, String text) {
createOrUpdate(id, field, text);
}
@Override
public void updateIndex(NitriteId id, String field, String text) {
createOrUpdate(id, field, text);
}
@Override
public void deleteIndex(NitriteId id, String field, String text) {
try {
NitriteMap> indexMap
= indexMetaService.getIndexMap(field);
Set words = tokenizerService.tokenize(text);
for (String word : words) {
ConcurrentSkipListSet nitriteIds = indexMap.get(word);
if (nitriteIds != null) {
nitriteIds.remove(id);
if (nitriteIds.isEmpty()) {
indexMap.remove(word);
} else {
indexMap.put(word, nitriteIds);
}
}
}
} catch (IOException ioe) {
throw new IndexingException(errorMessage(
"failed to remove full-text index data for " + field + " with id " + id,
IE_REMOVE_FULL_TEXT_INDEX_FAILED));
}
}
@Override
public void deleteIndexesByField(String field) {
indexMetaService.dropIndex(field);
}
@Override
public Set searchByIndex(String field, String searchString) {
try {
if (searchString.startsWith("*") || searchString.endsWith("*")) {
return searchByWildCard(field, searchString);
} else {
return searchExactByIndex(field, searchString);
}
} catch (IOException ioe) {
throw new IndexingException(FAILED_TO_QUERY_FTS_DATA, ioe);
}
}
@Override
public void drop() {
// nothing to do. already handled by IndexingService
}
@Override
public void clear() {
// nothing to do. already handled by IndexingService
}
@Override
public void commit() {
// nothing to do.
}
@Override
public void close() {
// nothing to do.
}
private void createOrUpdate(NitriteId id, String field, String text) {
try {
NitriteMap> indexMap
= indexMetaService.getIndexMap(field);
Set words = tokenizerService.tokenize(text);
for (String word : words) {
ConcurrentSkipListSet nitriteIds = indexMap.get(word);
synchronized (indexLock) {
if (nitriteIds == null) {
nitriteIds = new ConcurrentSkipListSet<>();
}
}
nitriteIds.add(id);
indexMap.put(word, nitriteIds);
}
} catch (IOException ioe) {
throw new IndexingException(errorMessage(
"could not write full-text index data for " + text,
IE_FAILED_TO_WRITE_FTS_DATA), ioe);
}
}
private Set searchByWildCard(String field, String searchString) {
if (searchString.contentEquals("*")) {
throw new FilterException(STAR_NOT_A_VALID_SEARCH_STRING);
}
StringTokenizer stringTokenizer = new StringTokenizer(searchString);
if (stringTokenizer.countTokens() > 1) {
throw new FilterException(MULTIPLE_WORDS_WITH_WILD_CARD);
}
if (searchString.startsWith("*") && !searchString.endsWith("*")) {
return searchByLeadingWildCard(field, searchString);
} else if (searchString.endsWith("*") && !searchString.startsWith("*")) {
return searchByTrailingWildCard(field, searchString);
} else {
String term = searchString.substring(1, searchString.length() - 1);
return searchContains(field, term);
}
}
private Set searchByTrailingWildCard(String field, String searchString) {
if (searchString.equalsIgnoreCase("*")) {
throw new FilterException(INVALID_SEARCH_TERM_TRAILING_STAR);
}
NitriteMap> indexMap
= indexMetaService.getIndexMap(field);
Set idSet = new LinkedHashSet<>();
String term = searchString.substring(0, searchString.length() - 1);
for (Map.Entry> entry : indexMap.entrySet()) {
String key = (String) entry.getKey();
if (key.startsWith(term.toLowerCase())) {
idSet.addAll(entry.getValue());
}
}
return idSet;
}
private Set searchContains(String field, String term) {
NitriteMap> indexMap
= indexMetaService.getIndexMap(field);
Set idSet = new LinkedHashSet<>();
for (Map.Entry> entry : indexMap.entrySet()) {
String key = (String) entry.getKey();
if (key.contains(term.toLowerCase())) {
idSet.addAll(entry.getValue());
}
}
return idSet;
}
private Set searchByLeadingWildCard(String field, String searchString) {
if (searchString.equalsIgnoreCase("*")) {
throw new FilterException(INVALID_SEARCH_TERM_LEADING_STAR);
}
NitriteMap> indexMap
= indexMetaService.getIndexMap(field);
Set idSet = new LinkedHashSet<>();
String term = searchString.substring(1);
for (Map.Entry> entry : indexMap.entrySet()) {
String key = (String) entry.getKey();
if (key.endsWith(term.toLowerCase())) {
idSet.addAll(entry.getValue());
}
}
return idSet;
}
private Set searchExactByIndex(String field, String searchString) throws IOException {
NitriteMap> indexMap
= indexMetaService.getIndexMap(field);
Set words = tokenizerService.tokenize(searchString);
Map scoreMap = new HashMap<>();
for (String word : words) {
ConcurrentSkipListSet nitriteIds = indexMap.get(word);
if (nitriteIds != null) {
for (NitriteId id : nitriteIds) {
Integer score = scoreMap.get(id);
if (score == null) {
scoreMap.put(id, 1);
} else {
scoreMap.put(id, score + 1);
}
}
}
}
Map sortedScoreMap = sortByScore(scoreMap);
return sortedScoreMap.keySet();
}
}
