This is a custom synonym search module for the Jahia xCM platform that enables integrating different synonym search policies.
This module is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version
This module was developed by Benjamin Papez and 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.
The status of this development is a "Prototype" and is not targeted to be deployed and run on a production instance of Jahia xCM.
Module is targeted to be deployed to Jahia xCM version 6.5 (or later).
There are different approaches to use synonym queries. One can either use query time or index time synonym expansion. Jahia with this module supports both.
- Query time expansion
When deciding to use query time expansion, then synonym search will be done only for terms which start with ~ (tilde). Either the users need to know this syntax or one could make a search template, which automatically adds the tilde if the user clicks on a provided checkbox to also look for synonyms. Query time synonym expansion is limited to single terms and does not work with phrases.
- Index time expansion
With index time expansion all the synonyms are expanded already during indexing time, so synonyms will always be active on search and there is no need to explicitly set the tilde. The disadvantage of index time synonym expansion is that whenever you change the synonym dictionary, you need to recreate the whole index. The advantage iof index time expansion is that you can also use synonyms for phrases and also that the relevancy calculation will be more correct than with using query time expansion (see explanation in Solr ).
For both approaches you can decide whether you want to use a custom built synonym dictionary or whether you want to use an available synonym dictionary, like for instance the WordNet synonym dictionary. The custom build dictionary is enough if you want to just provide domain-specific synonyms like abbreviations or product names.
Jahia xCM version 6.5 already provides a synonym search capability out of the box (you do not need to install this module for it). It simply uses a Java properties file in which you can configure custom synonyms.
To activate it you need to configure the following files:
..\WEB-INF\etc\repository\jackrabbit\repository.xml ..\WEB-INF\var\repository\workspaces\default\workspace.xml ..\WEB-INF\var\repository\workspaces\live\workspace.xml
You need to add the following setting to the Workspace->SearchIndex element:
<param name="synonymProviderClass" value="org.apache.jackrabbit.core.query.lucene.PropertiesSynonymProvider"/> <param name="synonymProviderConfigPath" value="synonyms.properties"/>
The path interpreted relative to the index directory, which on default is:
..\WEB-INF\var\repository\workspaces\default\index\ ..\WEB-INF\var\repository\workspaces\live\index\
The syntax of the properties file is simply:
word1=word2 word3=word1 word2=word4
In the above case word1 will have as synonyms word2 and word3, whereas word2 will have as synonyms word1 and word4. The limitation of this syntax is, that the same word can not appear twice on the left hand side of the equation as only the last will be taken.
In order to use the existing English WordNet synonym dictionary, you can deploy this custom module to Jahia and then in the same files as mentioned above configure the Workspace->SearchIndex element and set:
<param name="synonymProviderClass" value="org.apache.jackrabbit.core.query.wordnet.WordNetSynonyms"/>
This way whenever the user prefixes a term with the tilde (e.g. ~construction) it will also search for words with a similar meaning.
Jahia already uses Apache Solr to offer faceting support, so we also provide with this module an integration of the Solr based SynonymFilter, which is used to expand words with their synonyms during indexing time.
To use it you first need to deploy this custom module and configure the same files as mentioned above, just that now you need to modify the exisiting "analyzer" parameter in the element Workspace->SearchIndex->:
<param name="analyzer" value="org.jahia.services.search.analyzer.SynonymAnalyzer"/>
After deploying the module, there will be a synonyms.txt file in the WEB-INFlibsynonymSearch-*.jar. This file has some example synonyms for testing. You can create your own synonyms.txt file and place it under WEB-INFclasses.
Notice that whenever you make changes in the synonyms.txt dictionary, you will manually trigger a reindexing of your site, by shutting the server down, deleting all indexes under:
..\WEB-INF\var\repository\workspaces\default\index\ ..\WEB-INF\var\repository\workspaces\live\index\
and then again start the server, which will automatically re-create the indexes on startup.
The syntax of the synonyms.txt file is explained in this Solr Wiki article
The synonym, ignoreCase, expand and tokenizerFactory parameters can be set in the file:
..\modules\synonymSearch\resources\JahiaSynonymSearch.properties
With index time synonym expansion you do not need to use the tilde during query time, as synonyms will be already automatically searched.