use an enum to specify the request source

application/src/main/java/org/opentripplanner/routing/algorithm/raptoradapter/transit/RaptorTransferIndex.java

@@ -28,14 +28,11 @@ public RaptorTransferIndex(
 
   /**
    * Create an index to be put into the transfer cache
-   *
-   * @param isRuntimeRequest true if the request originates from the client during the runtime,
-   *                         false if the request comes from transferCacheRequests in router-config.json
    */
   public static RaptorTransferIndex create(
     List<List<Transfer>> transfersByStopIndex,
     StreetSearchRequest request,
-    boolean isRuntimeRequest
+    RequestSource requestSource
   ) {
     var forwardTransfers = new ArrayList<List<RaptorTransfer>>(transfersByStopIndex.size());
     var reversedTransfers = new ArrayList<List<RaptorTransfer>>(transfersByStopIndex.size());
@@ -49,7 +46,7 @@ public static RaptorTransferIndex create(
     var stopIndices = IntStream.range(0, transfersByStopIndex.size());
     // we want to always parallelize the cache building during the startup
     // and only parallelize during runtime requests if the feature flag is on
-    if (!isRuntimeRequest || OTPFeature.ParallelRouting.isOn()) {
+    if (requestSource == RequestSource.CONFIG || OTPFeature.ParallelRouting.isOn()) {
       stopIndices = stopIndices.parallel();
     }
     stopIndices.forEach(fromStop -> {

application/src/main/java/org/opentripplanner/routing/algorithm/raptoradapter/transit/RequestSource.java

@@ -0,0 +1,12 @@
+package org.opentripplanner.routing.algorithm.raptoradapter.transit;
+
+public enum RequestSource {
+  /**
+   * The request comes from transferCacheRequests in router-config.json
+   */
+  CONFIG,
+  /**
+   * The request comes from a client routing request
+   */
+  RUNTIME,
+}

application/src/main/java/org/opentripplanner/routing/algorithm/raptoradapter/transit/request/RaptorRequestTransferCache.java

@@ -7,6 +7,7 @@
 import java.util.Objects;
 import java.util.concurrent.ExecutionException;
 import org.opentripplanner.routing.algorithm.raptoradapter.transit.RaptorTransferIndex;
+import org.opentripplanner.routing.algorithm.raptoradapter.transit.RequestSource;
 import org.opentripplanner.routing.algorithm.raptoradapter.transit.Transfer;
 import org.opentripplanner.routing.api.request.RouteRequest;
 import org.opentripplanner.routing.api.request.StreetMode;
@@ -39,7 +40,7 @@ public void put(List<List<Transfer>> transfersByStopIndex, RouteRequest request)
     final RaptorTransferIndex raptorTransferIndex = RaptorTransferIndex.create(
       transfersByStopIndex,
       cacheKey.request,
-      false
+      RequestSource.CONFIG
     );
 
     LOG.info("Initializing cache with request: {}", cacheKey.options);
@@ -59,7 +60,11 @@ private CacheLoader<CacheKey, RaptorTransferIndex> cacheLoader() {
       @Override
       public RaptorTransferIndex load(CacheKey cacheKey) {
         LOG.info("Adding runtime request to cache: {}", cacheKey.options);
-        return RaptorTransferIndex.create(cacheKey.transfersByStopIndex, cacheKey.request, true);
+        return RaptorTransferIndex.create(
+          cacheKey.transfersByStopIndex,
+          cacheKey.request,
+          RequestSource.RUNTIME
+        );
       }
     };
   }