diff --git a/hapi-fhir-base/src/main/java/ca/uhn/fhir/util/BundleUtil.java b/hapi-fhir-base/src/main/java/ca/uhn/fhir/util/BundleUtil.java
index d48969ae5ca..1d48b6a8fa9 100644
--- a/hapi-fhir-base/src/main/java/ca/uhn/fhir/util/BundleUtil.java
+++ b/hapi-fhir-base/src/main/java/ca/uhn/fhir/util/BundleUtil.java
@@ -12,6 +12,8 @@ import org.apache.commons.lang3.tuple.Pair;
 import org.hl7.fhir.instance.model.api.*;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Objects;
 import java.util.function.Consumer;
@@ -170,6 +172,39 @@ public class BundleUtil {
 		return entryListAccumulator.getList();
 	}
 
+	static int WHITE = 1;
+	static int GRAY = 2;
+	static int BLACK = 3;
+
+	public static IBaseBundle topologicalSort(FhirContext theContext, IBaseBundle theBundle) {
+		boolean isPossible = true;
+		HashMap<String, Integer> color = new HashMap<String, Integer>();
+		HashMap<String, List<String>> adjList = new HashMap<>();
+		List<String> topologicalOrder = new ArrayList<>();
+
+		List<List<String>> prerequisites = new ArrayList<>();
+
+		List<BundleEntryParts> bundleEntryParts = toListOfEntries(theContext, theBundle);
+		for (BundleEntryParts bundleEntryPart : bundleEntryParts) {
+			IBaseResource resource = bundleEntryPart.getResource();
+			String resourceId = resource.getIdElement().toString();
+			if (resourceId == null) {
+				if (bundleEntryPart.getFullUrl() != null) {
+					resourceId = bundleEntryPart.getFullUrl();
+				}
+			}
+			List<ResourceReferenceInfo> allResourceReferences = theContext.newTerser().getAllResourceReferences(resource);
+			String finalResourceId = resourceId;
+			allResourceReferences
+				.forEach(refInfo -> {
+					prerequisites.add(Arrays.asList(finalResourceId, refInfo.getResourceReference().getReferenceElement().getValue()));
+				});
+
+		}
+		System.out.println("zoop!!");
+		return null;
+	}
+
 
 	public static void processEntries(FhirContext theContext, IBaseBundle theBundle, Consumer<ModifiableBundleEntry> theProcessor) {
 		RuntimeResourceDefinition bundleDef = theContext.getResourceDefinition(theBundle);
diff --git a/hapi-fhir-jpaserver-base/src/test/java/ca/uhn/fhir/jpa/dao/r4/TransactionHookTest.java b/hapi-fhir-jpaserver-base/src/test/java/ca/uhn/fhir/jpa/dao/r4/TransactionHookTest.java
index 9b31ae1bce3..57e4ae32ec6 100644
--- a/hapi-fhir-jpaserver-base/src/test/java/ca/uhn/fhir/jpa/dao/r4/TransactionHookTest.java
+++ b/hapi-fhir-jpaserver-base/src/test/java/ca/uhn/fhir/jpa/dao/r4/TransactionHookTest.java
@@ -7,6 +7,7 @@ import ca.uhn.fhir.jpa.api.model.DaoMethodOutcome;
 import ca.uhn.fhir.rest.api.server.storage.DeferredInterceptorBroadcasts;
 import ca.uhn.fhir.rest.server.exceptions.ResourceGoneException;
 import ca.uhn.fhir.rest.server.exceptions.ResourceVersionConflictException;
+import ca.uhn.fhir.util.BundleUtil;
 import ca.uhn.test.concurrency.PointcutLatch;
 import com.google.common.collect.ListMultimap;
 import org.hl7.fhir.instance.model.api.IBaseResource;
@@ -14,7 +15,9 @@ import org.hl7.fhir.instance.model.api.IIdType;
 import org.hl7.fhir.r4.model.Bundle;
 import org.hl7.fhir.r4.model.DiagnosticReport;
 import org.hl7.fhir.r4.model.Observation;
+import org.hl7.fhir.r4.model.Organization;
 import org.hl7.fhir.r4.model.Patient;
+import org.hl7.fhir.r4.model.Quantity;
 import org.hl7.fhir.r4.model.Reference;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
@@ -41,6 +44,7 @@ public class TransactionHookTest extends BaseJpaR4SystemTest {
 	@Autowired
 	private IInterceptorService myInterceptorService;
 
+
 	@BeforeEach
 	public void beforeEach() {
 		myInterceptorService.registerAnonymousInterceptor(Pointcut.STORAGE_TRANSACTION_PROCESSED,  myPointcutLatch);
@@ -49,6 +53,44 @@ public class TransactionHookTest extends BaseJpaR4SystemTest {
 		myInterceptorService.registerAnonymousInterceptor(Pointcut.STORAGE_PRECOMMIT_RESOURCE_DELETED,  myPointcutLatch);
 	}
 
+	@Test
+	public void testTopologicalTransactionSorting() {
+
+		Bundle b = new Bundle();
+		Bundle.BundleEntryComponent bundleEntryComponent = b.addEntry();
+		final Observation obs1 = new Observation();
+		obs1.setStatus(Observation.ObservationStatus.FINAL);
+		obs1.setSubject(new Reference("Patient/P1"));
+		obs1.setValue(new Quantity(4));
+		obs1.setId("Observation/O1");
+		bundleEntryComponent.setResource(obs1);
+		bundleEntryComponent.getRequest().setMethod(Bundle.HTTPVerb.POST).setUrl("Observation");
+
+		bundleEntryComponent = b.addEntry();
+		final Observation obs2 = new Observation();
+		obs2.setStatus(Observation.ObservationStatus.FINAL);
+		obs2.setValue(new Quantity(4));
+		obs2.setId("Observation/O2");
+		bundleEntryComponent.setResource(obs2);
+		bundleEntryComponent.getRequest().setMethod(Bundle.HTTPVerb.POST).setUrl("Observation");
+
+		Bundle.BundleEntryComponent patientComponent = b.addEntry();
+		Patient pat1 = new Patient();
+		pat1.setId("Patient/P1");
+		pat1.setManagingOrganization(new Reference("Organization/Org1"));
+		patientComponent.setResource(pat1);
+		patientComponent.getRequest().setMethod(Bundle.HTTPVerb.POST).setUrl("Patient");
+
+		Bundle.BundleEntryComponent organizationComponent = b.addEntry();
+		Organization org1 = new Organization();
+		org1.setId("Organization/Org1");
+		organizationComponent.setResource(org1);
+		organizationComponent.getRequest().setMethod(Bundle.HTTPVerb.POST).setUrl("Patient");
+
+		BundleUtil.topologicalSort(myFhirCtx, b);
+
+	}
+
 	@Test
 	public void testHookShouldContainParamsForAllCreateUpdateDeleteInvocations() throws InterruptedException {