Allocation-free text utility

code/features-convert/summary-extraction/src/main/java/nu/marginalia/summary/heuristic/HeuristicTextUtil.java

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+package nu.marginalia.summary.heuristic;
+
+import org.apache.commons.lang3.StringUtils;
+
+import java.util.Collection;
+
+public class HeuristicTextUtil {
+
+    /** Return the number of occurrences of any word in the set of words in the text.
+     *
+     * The words must be all lower case, the text may be in any case. To count as a match,
+     * the word must be surrounded by non-alphabetic characters.
+     *
+     */
+    public static int countOccurrencesOfAnyWord(String text, Collection<String> wordsLc) {
+        if (StringUtils.isAllLowerCase(text)) {
+            return countOccurrencesOfAnyWordLowerCase(text, wordsLc);
+        }
+
+        int cnt = 0;
+        for (var word : wordsLc) {
+            if (containsWordInAnyCase(text, word)) {
+                cnt++;
+            }
+        }
+        return cnt;
+    }
+
+    public static boolean containsWordInAnyCase(String text, String wordLowerCase) {
+        int pos = StringUtils.indexOfIgnoreCase(text, wordLowerCase);
+        int wl = wordLowerCase.length();
+
+        while (pos >= 0) {
+            if (pos > 0) {
+                char c = text.charAt(pos - 1);
+                if (Character.isAlphabetic(c) || Character.isDigit(c)) {
+                    pos = StringUtils.indexOfIgnoreCase(text, wordLowerCase, pos + 1);
+                    continue;
+                }
+            }
+            if (pos + wl < text.length()) {
+                char c = text.charAt(pos + wl);
+                if (Character.isAlphabetic(c) || Character.isDigit(c)) {
+                    pos = StringUtils.indexOfIgnoreCase(text, wordLowerCase, pos + 1);
+                    continue;
+                }
+            }
+            return true;
+        }
+        return false;
+    }
+
+    public static int countOccurrencesOfAnyWordLowerCase(String textLc, Collection<String> wordsLc) {
+        int cnt = 0;
+        for (var word : wordsLc) {
+            if (containsWordAllLowerCase(textLc, word)) {
+                cnt++;
+            }
+        }
+        return cnt;
+    }
+
+    public static boolean containsWordAllLowerCase(String text, String wordLowerCase) {
+        int pos = text.indexOf(wordLowerCase);
+        int wl = wordLowerCase.length();
+
+        while (pos >= 0) {
+            if (pos > 0) {
+                char c = text.charAt(pos - 1);
+                if (Character.isAlphabetic(c) || Character.isDigit(c)) {
+                    pos = text.indexOf(wordLowerCase, pos + 1);
+                    continue;
+                }
+            }
+            if (pos + wl < text.length()) {
+                char c = text.charAt(pos + wl);
+                if (Character.isAlphabetic(c) || Character.isDigit(c)) {
+                    pos = text.indexOf(wordLowerCase, pos + 1);
+                    continue;
+                }
+            }
+            return true;
+        }
+        return false;
+    }
+
+}

code/features-convert/summary-extraction/src/test/java/nu/marginalia/summary/heuristic/HeuristicTextUtilTest.java

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+package nu.marginalia.summary.heuristic;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class HeuristicTextUtilTest {
+
+    @Test
+    void countOccurrencesOfAnyWord() {
+        String sentence = "B A Baracus was an expert with the Abacus";
+        assertEquals(4, HeuristicTextUtil.countOccurrencesOfAnyWord(sentence, Set.of("b", "a", "baracus", "abacus")));
+    }
+
+    @Test
+    void containsWordInAnyCase() {
+        String sentence = "B A Baracus was an expert with the Abacus";
+
+        assertTrue(HeuristicTextUtil.containsWordInAnyCase(sentence, "b"));
+        assertTrue(HeuristicTextUtil.containsWordInAnyCase(sentence, "a"));
+        assertTrue(HeuristicTextUtil.containsWordInAnyCase(sentence, "baracus"));
+        assertTrue(HeuristicTextUtil.containsWordInAnyCase(sentence, "abacus"));
+        assertFalse(HeuristicTextUtil.containsWordInAnyCase(sentence, "cus"));
+    }
+
+    @Test
+    void containsWordAllLowerCase() {
+        String sentence = "b a baracus was an expert with the abacus";
+
+        assertTrue(HeuristicTextUtil.containsWordInAnyCase(sentence, "b"));
+        assertTrue(HeuristicTextUtil.containsWordInAnyCase(sentence, "a"));
+        assertTrue(HeuristicTextUtil.containsWordInAnyCase(sentence, "baracus"));
+        assertTrue(HeuristicTextUtil.containsWordInAnyCase(sentence, "abacus"));
+        assertFalse(HeuristicTextUtil.containsWordInAnyCase(sentence, "cus"));
+    }
+
+}