Building and Integrating Snowball Stemmer for OpenNLP

This guide outlines the steps to build the Snowball compiler, generate stemmer classes, and integrate them into OpenNLP.

Prerequisites

  • A Unix-like environment with make installed.
  • Access to the Snowball repository.
  • The OpenNLP repository checked out locally.

Procedure

1. Clone and Build the Snowball Compiler

Clone the Snowball repository and build the compiler using make:

git clone https://github.com/snowballstem/snowball.git
cd snowball
make

This will generate the snowball compiler in the root directory of the repository.

Run the Snowball Compiler

Run the Snowball compiler to generate the stemmer code.

#!/bin/bash

# Define an array of languages
languages=("arabic" "catalan" "danish" "dutch" "english" "finnish" "french" "german" "greek" "hungarian" "indonesian" "irish" "italian" "norwegian" "porter" "portuguese" "romanian" "russian" "spanish" "swedish" "turkish")

# Base paths
snowball_exec_path="../snowball"
output_base="../../../../IdeaProjects/opennlp/opennlp-tools/src/main/java/opennlp/tools/stemmer/snowball"

# Loop through the languages and execute the command
for lang in "${languages[@]}"; do
  "${snowball_exec_path}" "${lang}.sbl" -java -o "${output_base}/${lang}Stemmer"
done

Usage:

  1. Save this script as generate_stemmers.sh at the appropriate location.
  2. Make it executable with chmod +x generate_stemmers.sh.
  3. Run it using ./generate_stemmers.sh.

Manually Reformat Code to Match OpenNLP Style

  • Open the generated Java files in your preferred IDE or text editor.
  • Reformat the code to match the OpenNLP code style. This may include:
  • Adjusting indentation.
  • Renaming variables or methods as needed.
  • Ensuring proper spacing and alignment.

Add License Information

  • Ensure each generated file includes the appropriate license information for both Snowball and OpenNLP.