(query) Always generate an ngram alternative, suppresses generation of multiple identical query branches

code/functions/search-query/java/nu/marginalia/functions/searchquery/query_parser/QueryExpansion.java

@@ -11,6 +11,7 @@ import org.apache.commons.lang3.StringUtils;
 
 import java.util.*;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
 /** Responsible for expanding a query, that is creating alternative branches of query execution
  *  to increase the number of results
@@ -23,7 +24,8 @@ public class QueryExpansion {
     private final List<ExpansionStrategy> expansionStrategies = List.of(
             this::joinDashes,
             this::splitWordNum,
-            this::joinTerms
+            this::joinTerms,
+            this::ngramAll
     );
 
     @Inject
@@ -63,6 +65,22 @@ public class QueryExpansion {
     }
 
 
+    public void ngramAll(QWordGraph graph) {
+        List<QWord> parts = new ArrayList<>();
+
+        for (var qw : graph) {
+            if (qw.isBeg() || qw.isEnd())
+                continue;
+
+            parts.add(qw);
+        }
+
+        if (parts.size() > 1) {
+            graph.addVariantForSpan(parts.getFirst(), parts.getLast(),
+                    parts.stream().map(QWord::word).collect(Collectors.joining("_")));
+        }
+    }
+
     // Turn 'MP3' into 'MP-3'
     public void splitWordNum(QWordGraph graph) {
         for (var qw : graph) {

code/functions/search-query/java/nu/marginalia/functions/searchquery/query_parser/model/QWord.java

@@ -2,6 +2,8 @@ package nu.marginalia.functions.searchquery.query_parser.model;
 
 import ca.rmen.porterstemmer.PorterStemmer;
 
+import java.util.Objects;
+
 public record QWord(
         int ord,
         boolean variant,
@@ -48,4 +50,22 @@ public record QWord(
     public String toString() {
         return STR."q{\{word}}";
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        QWord qWord = (QWord) o;
+        return variant == qWord.variant && Objects.equals(word, qWord.word) && Objects.equals(stemmed, qWord.stemmed) && Objects.equals(isOriginal(), qWord.isOriginal());
+    }
+
+    @Override
+    public int hashCode() {
+        int result = Boolean.hashCode(variant);
+        result = 31 * result + Objects.hashCode(stemmed);
+        result = 31 * result + Objects.hashCode(word);
+        result = 31 * result + Objects.hashCode(isOriginal());
+        return result;
+    }
 }

code/functions/search-query/java/nu/marginalia/functions/searchquery/query_parser/model/QWordGraph.java

@@ -19,8 +19,8 @@ public class QWordGraph implements Iterable<QWord> {
     public record QWordGraphLink(QWord from, QWord to) {}
 
     private final List<QWordGraphLink> links = new ArrayList<>();
-    private final Map<QWord, List<QWord>> fromTo = new HashMap<>();
+    private final Map<Integer, List<QWord>> fromTo = new HashMap<>();
-    private final Map<QWord, List<QWord>> toFrom = new HashMap<>();
+    private final Map<Integer, List<QWord>> toFrom = new HashMap<>();
 
     private int wordId = 0;
 
@@ -79,8 +79,8 @@ public class QWordGraph implements Iterable<QWord> {
 
     public void addLink(QWord from, QWord to) {
         links.add(new QWordGraphLink(from, to));
-        fromTo.computeIfAbsent(from, k -> new ArrayList<>()).add(to);
+        fromTo.computeIfAbsent(from.ord(), k -> new ArrayList<>()).add(to);
-        toFrom.computeIfAbsent(to, k -> new ArrayList<>()).add(from);
+        toFrom.computeIfAbsent(to.ord(), k -> new ArrayList<>()).add(from);
     }
 
     public List<QWordGraphLink> links() {
@@ -103,20 +103,20 @@ public class QWordGraph implements Iterable<QWord> {
     }
 
     public List<QWord> getNext(QWord word) {
-        return fromTo.getOrDefault(word, List.of());
+        return fromTo.getOrDefault(word.ord(), List.of());
     }
     public List<QWord> getNextOriginal(QWord word) {
-        return fromTo.getOrDefault(word, List.of())
+        return fromTo.getOrDefault(word.ord(), List.of())
                 .stream()
                 .filter(QWord::isOriginal)
                 .toList();
     }
 
     public List<QWord> getPrev(QWord word) {
-        return toFrom.getOrDefault(word, List.of());
+        return toFrom.getOrDefault(word.ord(), List.of());
     }
     public List<QWord> getPrevOriginal(QWord word) {
-        return toFrom.getOrDefault(word, List.of())
+        return toFrom.getOrDefault(word.ord(), List.of())
                 .stream()
                 .filter(QWord::isOriginal)
                 .toList();