Apache Solr is a search platform built on Apache Lucene. It provides powerful indexing and search capabilities along with features like real-time indexing, faceted search, caching, and replication. Solr configuration is done through XML files that define aspects like tokenization, stemming, synonyms, and stop words. Solr uses REST services and exposes a HTTP interface to provide search functionality in a stateless manner.

1. APACHE SOLR
A LITTLE INTRODUCTION TO SEARCH
ENGINES.

2. TECHNOLOGIES
Mainly, We are gonna talk about these
“technologies”:
● Apache SOLR
● Maven
● Rest Services, Java, Lucene, Google, and
many more...

3. Lucene
● Library which provides high performance text
operations.
● Inverted index.
● Plain text.
● Different operations with text i.e: delete articles.
● Since Java 1.4
● Indexes stored in disc.

4. Lucene
● Less dependency with index size.
● Higher text search flexibility. Synonyms,
phonetics searches...
● Ranking.
All these features does Lucene better than
DataBases when text searches are necessary
in our applications.

5. Lucene

6. SOLR
● Http access to Lucene
● Caches to improve performane
● Admin web interface
● XML configuration
● Faceted search
● Distributed service
● Solrj client

7. SOLR
Basic search configuration
Parameter Description
q What is searched (Name: Music)
rows Max results shown
facets Faceted search
sort It sorts the results i.e: name asc
fl Fields returned by the server
fq Caching results
... More and more parameters

8. SOLR
Advanced search:
● It's configurated through the xml files.
– Tokens
– Stemming
– Synonyms
– Stop words
– N-Gamas

9. SOLR
The Solr Home directory typically contains the following subdirectories...
conf/
This directory is mandatory and must contain your solrconfig.xml
and schema.xml. Any other optional configuration files would also
be kept here.
data/
This directory is the default location where Solr will keep your
index, and is used by the replication scripts for dealing with
snapshots. You can override this location in the solrconfig.xml
and scripts.conf files. Solr will create this directory if it
does not already exist.
lib/
This directory is optional. If it exists, Solr will load any Jars
found in this directory and use them to resolve any "plugins"
specified in your solrconfig.xml or schema.xml (ie: Analyzers,
Request Handlers, etc...). Alternatively you can use the <lib>
syntax in solrconfig.xml to direct Solr to your plugins. See the
example solrconfig.xml file for details.
bin/
This directory is optional. It is the default location used for
keeping the replication scripts .

10. SOLR

11. REST Services
Set of architectural principles:
● Use HTTP methods explicitly.
● Stateless.
● Expose directory structure-like URIs.
● Transfer XML, JavaScript Object Notation
(JSON), or both.

12. Maven
● Project life cycle control.
● Test, compile, install, deployment...
● Control of dependencies
● Many plugins
● Community