Programming language: Clojure
License: GNU General Public License v3.0 or later
Latest version: v0.9.0-SNAPSHOT

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Based on the "Natural Language Processing" category.
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  • Lingua

    The most accurate natural language detection library for Java and the JVM, suitable for long and short text alike

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License pipeline status Maven Central

Beagle is a detector of interesting things in text. Its intended use is in-stream search applications. Suppose you need to monitor a stream of text documents such as web crawl results, chat messages, or corporate documents in order to identify keywords, phrases, regexes, and complex search queries of interest. With Beagle you can quickly be up and running with such a system, allowing you to focus on productively monitoring your documents.

Beagle is based on the Lucene monitor library which is based on Luwak.


Phrase Annotator Usage

(require '[beagle.phrases :as phrases])

(let [dictionary [{:text "to be annotated" :id "1"}]
      highlighter-fn (phrases/highlighter dictionary)]
  (highlighter-fn "before annotated to be annotated after annotated"))
=> ({:text "to be annotated", :type "LABEL", :dict-entry-id "1", :meta {}, :begin-offset 17, :end-offset 32})

;; Case sensitivity is controlled per dictionary entry 
(let [dictionary [{:text "TO BE ANNOTATED" :id "1" :case-sensitive? false}]
      highlighter-fn (phrases/highlighter dictionary)]
  (highlighter-fn "before annotated to be annotated after annotated"))
=> ({:text "to be annotated", :type "LABEL", :dict-entry-id "1", :meta {}, :begin-offset 17, :end-offset 32})

;; ASCII folding is controlled per dictionary entry
(let [dictionary [{:text "TÖ BE ÄNNÖTÄTED" :id "1" :case-sensitive? false :ascii-fold? true}]
      highlighter-fn (phrases/highlighter dictionary)]
  (highlighter-fn "before annotated to be annotated after annotated"))
=> ({:text "to be annotated", :type "LABEL", :dict-entry-id "1", :meta {}, :begin-offset 17, :end-offset 32})

;; Stemming is supported for multiple languages per dictionary entry
(let [dictionary [{:text "Kaunas" :id "1" :stem? true :stemmer :lithuanian}]
      highlighter-fn (phrases/highlighter dictionary)]
  (highlighter-fn "Kauno miestas"))
=> ({:text "Kauno", :type "PHRASE", :dict-entry-id "1", :meta {}, :begin-offset 0, :end-offset 5})

;; Phrases also support slop (i.e. terms edit distance) per dictionary entry
(let [txt "before start and end after"
      dictionary [{:text "start end" :id "1" :slop 1}]
      highlighter-fn (phrases/highlighter dictionary)]
  (highlighter-fn txt))
=> ({:text "start and end", :type "PHRASE", :dict-entry-id "1", :meta {}, :begin-offset 7, :end-offset 20})

;; Every phrase can specify which tokenizer to use
(let [txt "[URGENT!] Do this immediately!"
      dictionary [{:text "[URGENT!]" :id "a" :tokenizer :whitespace}
                  {:text "[URGENT!]" :id "b" :tokenizer :standard}]
      highlighter-fn (phrases/highlighter dictionary)]
  (clojure.pprint/pprint (highlighter-fn txt)))
({:text "[URGENT!]",
  :type "PHRASE",
  :dict-entry-id "a",
  :meta {},
  :begin-offset 0,
  :end-offset 9}
 {:text "URGENT",
  :type "PHRASE",
  :dict-entry-id "b",
  :meta {},
  :begin-offset 1,
  :end-offset 7})

;; Ensure that phrase terms are matched in the provided order
;; e.g. NOT preserving order (default)
(let [txt "Mill Token"
      dictionary [{:text "Token Mill" :slop 2 :in-order? false}]
      highlighter-fn (phrases/highlighter dictionary)]
  (highlighter-fn txt))
=> [{:text "Mill Token" :type "PHRASE" :dict-entry-id "0" :meta {} :begin-offset 0 :end-offset 10}]
;; e.g. Preserving order
(let [txt "Mill Token"
      dictionary [{:text "Token Mill" :slop 2 :in-order? true}]
      highlighter-fn (phrases/highlighter dictionary)]
  (highlighter-fn txt))
=> ()

Java Interface to the Phrase Highlighter


import lt.tokenmill.beagle.phrases.Annotation;
import lt.tokenmill.beagle.phrases.Annotator;
import lt.tokenmill.beagle.phrases.DictionaryEntry;

import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;

public class Main {
    public static void main(String[] args) {
        DictionaryEntry dictionaryEntry = new DictionaryEntry("test phrase");
        Annotator annotator = new Annotator(Arrays.asList(dictionaryEntry));
        Collection<Annotation> annotations = annotator.annotate("This is my test phrase");
        annotations.forEach(s -> System.out.println("Annotated: \'" + s.text() + "\' at offset: " + s.beginOffset() + ":" + s.endOffset()));

// => Annotated: 'test phrase' at offset: 11:22

The available options for the Java API are explained with examples in the Java Interface for Phrase Highlighting wiki page.

All the options that are present in the Clojure interface are also available for use in Java, just convert Clojure keywords to Java strings, e.g.

:case-sensitive? => "case-sensitive?"

Project Setup with Maven

The library is deployed in the Maven Central Repository and you can just add the beagle dependency to your pom.xml:


Lucene Query Support


(require '[beagle.lucene-alpha :as lucene])

(let [txt "some text this other that"
        dictionary [{:text "this AND that" :id "1" :slop 1}]
        annotator-fn (lucene/annotator dictionary)]
  (annotator-fn txt {}))
=> ({:text "this AND that", :type "QUERY", :dict-entry-id "1", :meta {}})


The performance was measured on a desktop PC with Ubuntu 19.04 and 8-core Ryzen 1700.

The test setup was for news articles and dictionary made up of names of city names in USA.

Code and data for benchmarking and more benchmarks can be found here.


Average time spent per document ranged from 1.58 ms for dictionary of 5k phrases to 4.58 ms per document for 80k phrases.

[alt text](charts/st-avg-per-doc.png)

Throughput of docs analyzed ranged from 626 docs/sec for dictionary of 5k phrases to 210 docs/sec for 80k phrases.

[alt text](charts/st-throughput-per-sec.png)

Max time spent per document has couple of spikes when processing a document takes ~1000ms. These spikes should have been caused either by GC pauses, or JVM deoptimizations. Aside from those spikes, max time ranges grows steadily from 15 ms to 72 ms as the dictionary size grows.

Min time spent per document is fairly stable for any dictionary size and is about 0.45 ms. Most likely these are the cases when Presearcher haven't found any candidate queries to run against the document.

[alt text](charts/st-min-max-per-doc.png)


Using core.async pipeline time spent per single doc ranged from 3.38 ms for dictionary of 5k phrases to 15.34 ms per document for 80k phrases.

[alt text](charts/mt-avg-per-doc.png)

Total time spent to process all 10k docs ranged from 2412 ms for dictionary of 5k phrases to 12595 ms per document for 80k phrases.

[alt text](charts/mt-total.png)

Throughput of docs analyzed ranged from 4143 docs/sec for dictionary of 5k phrases to 793 docs/sec for 80k phrases.

[alt text](charts/mt-throughput-per-sec.png)

Max time spent per document has risen fairy steady from 24.15 ms for dictionary of 10k phrases to 113.45 ms per document for 60k phrases.

Min time spent per document varied from 0.6 ms for dictionary of 10k phrases to 1.1 ms per document for 55k phrases.

[alt text](charts/mt-min-max-per-doc.png)

Conclusions about Performance

Processing of a one document on average is faster in the single-thread mode by roughly by 3x compared to multi-threaded mode but even in multi-threaded mode one document rarely takes more than 10 ms.

In multi-threaded mode throughput grows with the number on CPU cores almost linearly: 4143/8=518 docs per core per sec in multi-threaded mode while in single-thread mode 626 docs per core per sec.

Dictionary Readers

Three file formats are supported: csv, edn, json.

CSV Dictionary Format

Separator: "," Escape: "\""

The first line MUST be a header.

Supported header keys: ["text" "type" "id" "synonyms" "case-sensitive?" ":ascii-fold?" "meta"]

Order is not important.

Under synonyms, there should be a list of string separated by ";" Under meta, there should be a list of strings separated by ";". Even number of strings is expected. In case of odd number, last one is ignored.

Dictionary Validator

Accepts any number of dictionaries to validate as long as they are provided in pairs as '"/path/to/dictionary/file" "file-type"'

Supported File Types

  • csv
  • json
  • edn


  • If any dictionary is invalid exception will be thrown with exit status 1



To use validator directly execute command: clj -m beagle.validator "/path/to/dictionary/file" "file-type" "/path/to/dictionary/file2" "file-type" & ...

clj -m beagle.validator "your-dict.csv" "csv" "your-other-dict.json" "json"


Example in Gitlab CI:

  stage: dictionary-validation
  when: always
  image: tokenmill/beagle-dictionary-validator
    - >
      /path/to/dict.csv csv
      /path/to/dict.json json
      /path/to/dict.edn edn

Dictionary Optimizer

Supported optimizations:

  • Remove duplicate dictionary entries
  • Merge synonyms
  • Synonyms and text equality check

There are cases when dictionary entries can't be merged:

  • Differences in text analysis


(require '[beagle.dictionary-optimizer :as optimizer])

; Remove duplicates
(let [dictionary [{:text "TO BE ANNOTATED" :id "1"}
                  {:text "TO BE ANNOTATED"}]]
  (optimizer/optimize dictionary))
=> ({:text "TO BE ANNOTATED", :id "1"})

; Merge synonyms
(let [dictionary [{:text "TO BE ANNOTATED" :synonyms ["ONE"]}
                  {:text "TO BE ANNOTATED" :synonyms ["TWO"]}]]
  (optimizer/optimize dictionary))
=> ({:text "TO BE ANNOTATED", :synonyms ("TWO" "ONE")})

; Synonyms and text equality check
(let [dictionary [{:text "TO BE ANNOTATED" :synonyms ["TO BE ANNOTATED"]}]]
  (optimizer/optimize dictionary))
=> ({:text "TO BE ANNOTATED", :synonyms ["TO BE ANNOTATED"]})

; Can't be merged because of differences in text analysis
(let [dictionary [{:text "TO BE ANNOTATED" :case-sensitive? true}
                  {:text "TO BE ANNOTATED" :case-sensitive? false}]]
  (optimizer/optimize dictionary))
=> ({:text "TO BE ANNOTATED", :case-sensitive? true} {:text "TO BE ANNOTATED", :case-sensitive? false})

Annotation Merger

Only annotations of the same type are merged.

Handled cases:

  • Duplicate annotations
  • Nested annotations


(require '[beagle.annotation-merger :as merger])

(let [dictionary [{:text "TEST"}
                  {:text "This TEST is"}]
      highlighter-fn (phrases/highlighter dictionary)
      annotations (highlighter-fn "This TEST is")]
  (println "Annotations: " annotations)
  (merger/merge-same-type-annotations annotations))
Annotations:  ({:text TEST, :type PHRASE, :dict-entry-id 0, :meta {}, :begin-offset 5, :end-offset 9} {:text This TEST is, :type PHRASE, :dict-entry-id 1, :meta {}, :begin-offset 0, :end-offset 12})
=> ({:text "This TEST is", :type "PHRASE", :dict-entry-id "1", :meta {}, :begin-offset 0, :end-offset 12})

;; You can also inline the need of merging annotations
(let [dictionary [{:text "TEST"}
                  {:text "This TEST is"}]
      highlighter-fn (phrases/highlighter dictionary)]
  (highlighter-fn "This TEST is" {:merge-annotations? true}))
=> ({:text "This TEST is", :type "PHRASE", :dict-entry-id "1", :meta {}, :begin-offset 0, :end-offset 12})


Copyright © 2019 TokenMill UAB.

Distributed under the The Apache License, Version 2.0.

*Note that all licence references and agreements mentioned in the Beagle README section above are relevant to that project's source code only.