lucene-ir-engine is an extremely simple Java application based on Apache Tika and Apache Lucene. It provides the following features:

• Parsing and extraction of metadata and text content from various documents;
• Indexing of plain text and metadata in order to create an inverted index related to parsed documents;
• Performing a simple search by term within a previously created inverted index.

To perform the tasks above, ir-engine uses two Java libraries:

• Apache Tika (1.20) provides Java APIs to detect and extract metadata and data from heterogenous file formats using existing parser libraries.
• Apache Lucene (7.6.0) is a powerful Java library for indexing and searching of text.

lucene-ir-engine is a Maven project organized as follows:

• lib: This directory includes all the JAR files required at runtime. Currently, it contains only the package lucene-backward-codecs-5.3.0.jar for backwards compatibility.

• pom.xml: It is an XML file that contains information about the project and configuration details used by Maven to build the project.

• src: This directory includes source files. It contains also the shell scripts to easily execute the utilities provided by lucene-ir-engine. These scripts are located into src/main/bin.

• README.txt: This README plain-text file.

To build the project, you can type the following command:

mvn clean install

To run the utilities of lucene-ir-engine, you can launch the following scripts (in /src/main/bin):

• indexer.sh aims at indexing metadata and text extracted from heterogeneous documents:

./indexer.sh -i /path/to/data_dir -o /path/to/index_dir -l /path/to/log_file -p /path/to/jar [-update] [-fork] [-ocr]

• searcher.sh aims at performing search queries against previously built Lucene indexes:

./searcher.sh -i /path/to/index_dir -s seed

• lister.sh aims at extracting the list of keywords in the Lucene indexes:

./lister.sh -i /path/to/index_dir -o /path/to/output_file

Furthermore, the scripts for Microsoft Windows systems are provided into the same directory.

A suitable dataset for testing lucene-ir-engine is govdocs1 provided by (Digital Corpora](http://digitalcorpora.org/corpora/files)

The last release of lucene-ir-engine relies on Apache Lucene 5.3.0. Lucene 5.x still supports the numerous 4.x index formats, whereas support for 3.x indexes has been removed. Therefore, lucene-ir-engine is able to perform queries against 4.x indexes if the package lucene-backward-codecs-5.3.0.jar is provided in the classpath. Currently, the script searcher.sh requires that package, that is located into the lib directory.

Apache License, version 2.0