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| </div><div id='content' class='page-1'><div class='row'><div class='row-fluid'><div class='col-lg-3'><ul class='nav-sidebar'><li><a href='./'>Blog index</a></li><li class='active'><a href='#doc'>Groovy Haiku processing</a></li><li><a href='#_example_1_finding_the_distinct_letters' class='anchor-link'>Example 1: Finding the distinct letters</a></li><li><a href='#_example_2_splitting_letters_into_unique_and_duplicate_partitions' class='anchor-link'>Example 2: Splitting letters into unique and duplicate partitions</a></li><li><a href='#_example_3_finding_the_top_used_letters' class='anchor-link'>Example 3: Finding the top used letters</a></li><li><a href='#_example_3_other_variations' class='anchor-link'>Example 3: Other variations</a></li><li><a href='#_further_information' class='anchor-link'>Further information</a></li></ul><br/><ul class='nav-sidebar'><li style='padding: 0.35em 0.625em; background-color: #eee'><span>Related posts</span></li><li><a href='./deep-learning-and-eclipse-collections'>Deep Learning and Eclipse Collections</a></li><li><a href='./groovy-null-processing'>Groovy Processing Nulls In Lists</a></li><li><a href='./deck-of-cards-with-groovy'>Deck of cards with Groovy, JDK collections and Eclipse Collections</a></li><li><a href='./groovy-list-processing-cheat-sheet'>Groovy List Processing Cheat Sheet</a></li><li><a href='./lego-bricks-with-groovy'>Lego Bricks with Groovy</a></li><li><a href='./wordle-checker'>Checking Wordle with Groovy</a></li><li><a href='./calculating-fibonacci-with-groovy-revisited'>Calculating Fibonacci with Groovy revisited</a></li><li><a href='./zipping-collections-with-groovy'>Zipping Collections with Groovy</a></li><li><a href='./fruity-eclipse-collections'>Fruity Eclipse Collections</a></li></ul></div><div class='col-lg-8 col-lg-pull-0'><a name='doc'></a><h1>Groovy Haiku processing</h1><p><span>Author: <i>Paul King</i></span><br/><span>Published: 2023-11-07 07:22PM</span></p><hr/><div id="preamble"> |
| <div class="sectionbody"> |
| <div class="paragraph"> |
| <p>This blog looks at some Groovy solutions for the examples in the |
| <a href="https://medium.com/javarevisited/haiku-for-java-using-text-blocks-6b7862ccd067">Haiku for Java using Text Blocks</a> post by <a href="https://twitter.com/TheDonRaab">Donald Raab</a>. In his example, |
| he is making use of Java text blocks, but Groovy already supports similar functionality |
| with its multi-line strings, so we won’t elaborate further on that aspect.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Here is some of Donald’s creative writing:</p> |
| </div> |
| <div class="paragraph"> |
| <p><span class="image"><img src="https://miro.medium.com/v2/resize:fit:1400/format:webp/1*zcMH0Q37PFrGS4bC2EHqiw.png" alt="text of Donald Raab’s haikus"></span></p> |
| </div> |
| <div class="paragraph"> |
| <p>In his examples, he processes those examples in various ways. We’ll look at doing the same |
| examples using Groovy.</p> |
| </div> |
| <div class="paragraph"> |
| <p>There has also been an excellent follow-on discussion of these examples in a recent |
| <a href="https://www.youtube.com/watch?v=wW7uzc61tZ8">JEP Café video</a> by |
| <a href="https://twitter.com/JosePaumard">José Paumard</a>.</p> |
| </div> |
| <div class="paragraph"> |
| <p>If you want more background about the examples, we highly recommend reading Donald’s |
| <a href="https://medium.com/javarevisited/haiku-for-java-using-text-blocks-6b7862ccd067">blog</a> |
| or watching José’s |
| <a href="https://www.youtube.com/watch?v=wW7uzc61tZ8">video</a>.</p> |
| </div> |
| </div> |
| </div> |
| <div class="sect1"> |
| <h2 id="_example_1_finding_the_distinct_letters">Example 1: Finding the distinct letters</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"> |
| <p>In this example, we want to see all the individual letters used in the haiku text. |
| We will disregard any punctuation characters and convert all letters to lowercase |
| since we don’t care about the distinction of case.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Here is the Groovy code:</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="prettyprint highlight"><code data-lang="groovy">assert haiku.codePoints().toArray() |
| .findAll(Character::isAlphabetic) |
| .collect(Character::toLowerCase) |
| .toUnique() |
| .collect(Character::toString) |
| .join() == 'breakingthoupvmwcdflsy'</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>We made a slight change compared to what is in the blog and video. |
| We used <code>codePoints()</code> instead of <code>chars()</code>. |
| While Donald’s current haiku text doesn’t contain any surrogate pairs, |
| we might as well be ready to handle any if they appear in the future. |
| You can see here that the following smiley face emoji is encoded |
| with two characters:</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="prettyprint highlight"><code data-lang="groovy">assert "😃".codePoints().mapToObj(Character::toString).toList()[0].size() == 2</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>And we are sure it’s only a matter of time before such symbols start appearing |
| more frequently in someone’s haiku.</p> |
| </div> |
| </div> |
| </div> |
| <div class="sect1"> |
| <h2 id="_example_2_splitting_letters_into_unique_and_duplicate_partitions">Example 2: Splitting letters into unique and duplicate partitions</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"> |
| <p>In the next example, we want to count the number of occurrences of each letter |
| and distinguish between letters which are duplicated multiple times and any |
| letters which might occur only once.</p> |
| </div> |
| <div class="paragraph"> |
| <p>We are going to use a map to store letters seen (the key) |
| and the number of times they occur (the value). |
| We’ll create a condition which is true for the map entries |
| which are seen only once.</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="prettyprint highlight"><code data-lang="groovy">var uniqueAndDuplicatePartitions = e -> e.value == 1</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>We use Groovy’s <code>countBy</code> method to create our map and then the <code>split</code> |
| method with our previous condition. This partitions the map into the unique |
| and duplicate sets.</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="prettyprint highlight"><code data-lang="groovy">assert haiku.codePoints().toArray() |
| .findAll(Character::isAlphabetic) |
| .collect(Character::toLowerCase) |
| .collect(Character::toString) |
| .countBy{ it } |
| .split(uniqueAndDuplicatePartitions) |
| *.size() == [0, 22]</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>When we check the sizes of the two sets, we discover that no letters occur only once |
| and that all letters are duplicated.</p> |
| </div> |
| </div> |
| </div> |
| <div class="sect1"> |
| <h2 id="_example_3_finding_the_top_used_letters">Example 3: Finding the top used letters</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"> |
| <p>Our final example is a variant of the previous example. |
| Instead of just finding unique and duplicate characters, |
| we want to find the three most frequently occurring letters.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Like before, we need a condition. This time, once |
| that we will use for sorting (in reverse order):</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="prettyprint highlight"><code data-lang="groovy">var byCountDescending = e -> -e.value</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>Now, we just sort using our condition and take the first 3.</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="prettyprint highlight"><code data-lang="groovy">assert haiku.codePoints().toArray() |
| .findAll(Character::isAlphabetic) |
| .collect(Character::toLowerCase) |
| .collect(Character::toString) |
| .countBy{ it } |
| .sort(byCountDescending) |
| .take(3) == [e:94, t:65, i:62]</code></pre> |
| </div> |
| </div> |
| </div> |
| </div> |
| <div class="sect1"> |
| <h2 id="_example_3_other_variations">Example 3: Other variations</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"> |
| <p>We can also use Eclipse Collections for this:</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="prettyprint highlight"><code data-lang="groovy">var top3 = Strings.asCodePoints(haiku) |
| .select(Character::isAlphabetic) |
| .collectInt(Character::toLowerCase) |
| .collect(Character::toString) |
| .toBag() |
| .topOccurrences(3) |
| |
| [e:94, t:65, i:62].eachWithIndex{ k, v, i -> |
| assert top3[i] == PrimitiveTuples.pair(k, v) |
| }</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>Using the <code>Bag</code> and its <code>topOccurrences</code> method have done much of the hard work for us. |
| In fact, this solution also has a behavioral difference in the presence of ties which |
| we’ll come back to later.</p> |
| </div> |
| <div class="paragraph"> |
| <p>We can of course use the Stream API as is done in both the blog and video. |
| Here is the Groovy equivalent:</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="prettyprint highlight"><code data-lang="groovy">assert haiku.codePoints() |
| .filter(Character::isAlphabetic) |
| .map(Character::toLowerCase) |
| .mapToObj(Character::toString) |
| .collect(Collectors.groupingBy( |
| Function.identity(), |
| Collectors.counting() |
| )) |
| .entrySet() |
| .stream() |
| .sorted(Map.Entry.comparingByValue().reversed()) |
| .limit(3) |
| .toList() |
| .collectEntries() == [e:94, t:65, i:62]</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>The video makes the point that the above code is quite technical in nature in |
| that you need to keep track of how we are using the map to model our problem |
| domain in order to understand what each processing step is doing.</p> |
| </div> |
| <div class="paragraph"> |
| <p>It suggests using records to better capture a little domain model |
| and make our code more intuitive. Let’s look at doing the same thing on Groovy.</p> |
| </div> |
| <div class="paragraph"> |
| <p>Here are three records that we will use:</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="prettyprint highlight"><code data-lang="groovy">record Letter(int codePoint) { |
| Letter(int codePoint) { |
| this.codePoint = Character.toLowerCase(codePoint) |
| } |
| } |
| |
| record LetterCount(int count) implements Comparable<LetterCount> { |
| int compareTo(LetterCount other) { |
| Integer.compare(this.count, other.count) |
| } |
| } |
| |
| record LetterByCount(Letter letter, LetterCount count) { |
| LetterByCount(Letter letter, Integer count) { |
| this(letter, new LetterCount(count)) |
| } |
| static Comparator<? super LetterByCount> comparingByCount() { |
| Comparator.comparing(LetterByCount::count) |
| } |
| |
| }</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>Now our <em>collecting</em> and <em>sorting</em> steps are in terms of our domain model, |
| and it is a little easier to understand:</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="prettyprint highlight"><code data-lang="groovy">assert haiku.codePoints().toArray() |
| .findAll(Character::isAlphabetic) |
| .collect(Letter::new) |
| .countBy{ it } |
| .collect(LetterByCount::new) |
| .toSorted(LetterByCount.comparingByCount().reversed()) |
| .take(3) |
| *.letter |
| *.codePoint |
| .collect(Character::toString) == ['e', 't', 'i']</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>The video also goes into an interesting difference with the Eclipse Collections |
| version. The <code>topOccurrences</code> method from the bag class handles ties and in |
| the case of a tie returns both occurrences. There aren’t any ties in the top |
| 3 occurrences, nor indeed the top 14, but if you call <code>topOccurrences(15)</code>, |
| then 16 occurrences are returned. We can follow the suggestion in the video |
| which gives us the following Groovy code:</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="prettyprint highlight"><code data-lang="groovy">var byCountReversed = e -> -e.key |
| assert haiku.codePoints().toArray() |
| .findAll(Character::isAlphabetic) |
| .collect(Character::toLowerCase) |
| .collect(Character::toString) |
| .countBy{ it } |
| .groupBy{ k, v -> v } |
| .sort(byCountReversed) |
| .take(15) |
| *.value.sum()*.key == ['e', 't', 'i', 'a', |
| 'o', 'n', 's', 'r', |
| 'h', 'd', 'w', 'l', |
| 'u', 'm', 'p', 'c']</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>We are essentially doing two <em>grouping</em> statements, the first as part of <code>countBy</code> |
| and then a subsequent <code>groupBy</code> on values. As we can see, if we look at the top |
| 15 occurrences, 16 values are returned.</p> |
| </div> |
| </div> |
| </div> |
| <div class="sect1"> |
| <h2 id="_further_information">Further information</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"> |
| <p>Referenced sites:</p> |
| </div> |
| <div class="paragraph"> |
| <p><a href="https://www.youtube.com/watch?v=wW7uzc61tZ8" class="bare">https://www.youtube.com/watch?v=wW7uzc61tZ8</a></p> |
| </div> |
| <div class="paragraph"> |
| <p><a href="https://medium.com/javarevisited/haiku-for-java-using-text-blocks-6b7862ccd067" class="bare">https://medium.com/javarevisited/haiku-for-java-using-text-blocks-6b7862ccd067</a></p> |
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