Libresource maintain an index of all ressources. It allows users to perform keywords search on a subtree.
The search can be filtered by URI pattern and/or resource type. The search engine is case insensitive and the accentuated characters (éàèê...) are replaced during the indexation.
Note: the content of some file on the platform are indexed too (text files, ms-word files, ms-exel files, openoffice files, xml files...)
The search engine is based on the lucene framework (
http://jakarta.apache.org/lucene).
Figure 1 - LibreSource search engine
Search query syntax :
Query syntax is available in
lucene site.
Here is a short description of availables query syntaxs :
Wildcard Searches
To perform a single character wildcard search use the "?" symbol.
To perform a multiple character wildcard search use the "*" symbol.
The single character wildcard search looks for terms that match that with the
single character replaced. For example, to search for "text" or "test" you can use
the search: te?t
Multiple character wildcard searches looks for 0 or more characters. For
example, to search for test, tests or tester, you can use the search: test*
You can also use the wildcard searches in the middle of a term. te*t
Note: You cannot use a * or ? symbol as the first character of a search.
Fuzzy Searches
To do a fuzzy search use the tilde, "~", symbol at the end of a Single word
Term. For example to search for a term similar in spelling to "roam" use the fuzzy
search: roam~
This search will find terms like foam and roams
Proximity Searches
To do a proximity search use the tilde, "~", symbol at the end of a Phrase. For
example to search for a "apache" and "jakarta" within 10 words of each other in
a document use the search: "jakarta apache"~10
Boosting a Term
To boost a term use the caret, "^", symbol with a boost factor (a number) at
the end of the term you are searching. The higher the boost factor, the more
relevant the term will be.
Boosting allows you to control the relevance of a document by boosting its
term. For example, if you are searching for jakarta apache
and you want the term "jakarta" to be more relevant boost it using the ^
symbol along with the boost factor next to the term. You would type:
jakarta^4 apache
This will make documents with the term jakarta appear more
relevant. You can also boost Phrase Terms as in the example:
"jakarta apache"^4 "jakarta lucene"
By default, the boost factor is 1. Although the boost factor must be positive, it
can be less than 1 (e.g. 0.2)
BOOLEAN OPERATORS
Boolean operators allow terms to be combined through logic operators.
Lucene supports AND, "+", OR, NOT and "-" as Boolean operators(Note:
Boolean operators must be ALL CAPS).
OR
The OR operator is the default conjunction operator. This means that if there
is no Boolean operator between two terms, the OR operator is used. The OR
operator links two terms and finds a matching document if either of the terms
exist in a document. This is equivalent to a union using sets. The symbol || can
be used in place of the word OR.
To search for documents that contain either "jakarta apache" or just "jakarta"
use the query: "jakarta apache" jakarta or "jakarta apache" OR jakarta
AND
The AND operator matches documents where both terms exist anywhere in
the text of a single document. This is equivalent to an intersection using sets.
The symbol && can be used in place of the word AND.
To search for documents that contain "jakarta apache" and "jakarta lucene"
use the query: "jakarta apache" AND "jakarta lucene"
+
The "+" or required operator requires that the term after the "+" symbol exist
somewhere in a the field of a single document.
To search for documents that must contain "jakarta" and may contain "lucene"
use the query: +jakarta apache
NOT
The NOT operator excludes documents that contain the term after NOT. This
is equivalent to a difference using sets. The symbol ! can be used in place of the
word NOT.
To search for documents that contain "jakarta apache" but not "jakarta lucene"
use the query: "jakarta apache" NOT "jakarta lucene"
Note: The NOT operator cannot be used with just one term. For example, the
following search will return no results: NOT "jakarta apache"
-
The "-" or prohibit operator excludes documents that contain the term after the
"-" symbol.
To search for documents that contain "jakarta apache" but not "jakarta lucene"
use the query: "jakarta apache" -"jakarta lucene"