ENH: Add function for extracting all triples with a given predicate

src/main/ExternalTripleStore.kt

@@ -28,3 +28,10 @@ fun extractPrefixes(catalog: QueryCatalog): Map<String, String> {
     val matches = catalog.values.map { query -> regex.findAll(query) }.asSequence().flatten()
     return matches.map { match -> Pair(match.groupValues[0], match.groupValues[1]) }.toMap()
 }
+
+fun createExtractionQuery(query: ParsedSparqlQuery): String {
+    val prefix = query.prefixes.map { entry -> "PREFIX ${entry.key}: ${entry.value}" }.joinToString(separator = "\n")
+    val predicates = query.predicates.joinToString(separator = " ")
+    val select = "SELECT ?graph ?s ?p ?o {\nVALUES ?p { $predicates }\nGRAPH ?graph {?s ?p ?o}}"
+    return "$prefix\n$select"
+}

src/test/TestExternalTripleStore.kt

@@ -1,5 +1,8 @@
+import com.github.statnett.loadflowservice.ParsedSparqlQuery
+import com.github.statnett.loadflowservice.createExtractionQuery
 import com.github.statnett.loadflowservice.parseQuery
 import org.junit.jupiter.api.Test
+import kotlin.test.assertEquals
 import kotlin.test.assertTrue
 
 class TestExternalTripleStore {
@@ -10,4 +13,19 @@ class TestExternalTripleStore {
         assertTrue { queryContent.predicates.containsAll(expect) }
         assertTrue { queryContent.prefixes.isNotEmpty() }
     }
+
+    @Test
+    fun `test create extraction query`() {
+        val parsedQuery =
+            ParsedSparqlQuery(
+                mapOf("md" to "<http://md>", "cim" to "<http://cim>"),
+                setOf("cim:a", "md:b"),
+            )
+
+        val expectedQuery = (
+            "PREFIX md: <http://md>\nPREFIX cim: <http://cim>\nSELECT ?graph ?s ?p ?o {\n" +
+                "VALUES ?p { cim:a md:b }\nGRAPH ?graph {?s ?p ?o}}"
+        )
+        assertEquals(createExtractionQuery(parsedQuery), expectedQuery)
+    }
 }