alexander-efremov / aho-corasick-optimized

aho-corasick-optimized

Implementation of the Aho-Corasick string matching algorithm, which supposed to be Garbage Collector friendly. The automaton implemented using only the primitive data types in order to avoid Autoboxing and Unboxing conversions.

Usage

This implementation is self-sufficient. You can directly copy this class to your project: https://github.com/lagodiuk/aho-corasick-optimized/blob/master/src/main/java/com/lahodiuk/ahocorasick/AhoCorasickOptimized.java

public class Example {

	public static void main(String[] args) {
	
		// Construction of the the automaton
		AhoCorasickOptimized ac = new AhoCorasickOptimized("he", "she", "his", "hers");

		// The same automaton can be used for matching inside different texts
		String text1 = "ushers";
		System.out.println("\n Matching inside text 1: " + text1);
		// In case, when the pattern is found - the callback will be activated:
		ac.match(text1, (start, end, found) -> System.out.printf("%s: [%d..%d]%n", found, start, end));

		// Example of finding substrings inside another text
		String text2 = "ushers ushers ushers ushers ushers abc 123 xyz he she";
		System.out.println("\n Matching inside text 2: " + text2);
		ac.match(text2, (start, end, found) -> System.out.printf("%s: [%d..%d]%n", found, start, end));

		// The structure of automaton can be visualized using Graphviz format
		System.out.println("\n Graphviz structure of automaton:");
		System.out.println(ac.generateGraphvizAutomatonRepresentation(false))
	}
}

The generated automaton can be visualized using Graphviz software

Reference

The Aho-Corasick string matching algorithm, described in the paper: "Efficient String Matching: An Aid to Bibliographic Search", Alfred V. Aho, Margaret J. Corasick, Bell Laboratories, 1975