Integration Exercise: Java Library Wrapper

Exercise Summary

• You should create a gem using JRuby that wraps an existing Java library.
• Your gem should work with a Java library that doesn't already have a good wrapper.
• You should make the API for your library look and feel like Ruby, not Java.

Wrapping cue.language

For this assignment, I'm wrapping the cue.language library, which handles "counting strings, identifying languages, and removing stop words."

How to Use It

It's All In the TextComb Module

There are methods for splitting up text:

require 'text_comb'

string = "He must be a little nuts. He is. I mean he just isn't well
          screwed on is he?"

p TextComb.words(string).to_a

# prints:
["He", "must", "be", "a", "little", "nuts", "He", "is", "I", "mean"...

TextComb.sentences(string).each do |sentence|
  p sentence
end

# prints:
"He must be a little nuts. "
"He is. "
"I mean he just isn't well screwed on is he?"

TextComb.ngrams(string, 5).each do |ngram|
  p ngram
end

# prints:
"He must be a little"
"must be a little nuts"
"I mean he just isn't"
...

TextComb can take a guess at the language, and use the appropriate stop-words:

string = "That's a great mustache, grandma!"
TextComb.ngrams(string, 2, :stop_words=>:guess).to_a

# returns:
["great mustache", "mustache grandma"]

If it picks wrong, and you know what you're dealing with, you can specify:

TextComb.ngrams(string, 3, :stop_words=>:Croatian).each do |ngram|
  puts ngram
end

If you're curious, TextComb will tell you how it guessed:

string = "J'ai la moutarde dans ma moustache."
TextComb.guess_language(string).to_s   # "French"

Mix-in TextComb::StringExtensions

Extend a string with TextComb::StringExtensions, and it'll have those methods:

require 'text_comb'

motto = "I came. I saw. I hacked."
motto.extend(TextComb::StringExtensions)

motto.sentences.to_a    # ["I came. ", "I saw. ", "I hacked."]
motto.words.to_a.uniq   # ["I", "came", "saw", "hacked"]

Stop-words for n-grams work the same way, too.

string = "I saw red roosters at Ted's farm."
string.extend(TextComb::StringExtensions)
string.ngrams(2, :stop_words => :English).to_a

# returns:
["saw red", "red roosters", "Ted's farm"]

Make a TextComb::String

TextComb::String includes TextComb::StringExtensions, but delegates everything else to its string. It's like mixing TextComb::StringExtensions into your own string.

require 'text_comb'

littany = TextComb::String.new("I must not fear.")
littany.ngrams(3).to_a   # ["I must not", "must not fear"]

Even handier, there's the TextComb.string method to save you some finger-tapping.

require 'text_comb'
littany = TextComb.string("I must not fear.")
littany.words.to_a  # -> ["I", "must", "not", "fear."]

littany.guess_language.to_s  # -> :English

Future Plans

• code(TextComb.ngrams) currently yields whole strings - maybe split them into Arrays of words.