Merge pull request #40 from onaio/flatten_location_hierarchy

Flatten the LocationHierarchy endpoint response

README.md

@@ -308,6 +308,19 @@ Example:
 [GET] /List?_id=<some-id>&_count=<page-size>&_page=<page-number>&_sort=<some-sort>
 ```
 
+##### LocationHierarchy list mode
+
+The LocationHierarchy endpoint supports two response formats: tree and list. By
+default, the response format remains a tree, providing hierarchical location
+data. In addition, clients can request the endpoint to return location resources
+in a flat list format by providing a request parameter `mode=list`.
+
+Example:
+
+```
+[GET] /LocationHierarchy?identifier=<some-location-id>&mode=list&_count=<page-size>&_page=<page-number>&_sort=<some-sort>
+```
+
 #### Important Note:
 
 Developers, please update your client applications accordingly to accommodate

exec/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>org.smartregister</groupId>
     <artifactId>opensrp-gateway-plugin</artifactId>
-    <version>1.0.8</version>
+    <version>1.0.9</version>
   </parent>
 
   <artifactId>exec</artifactId>
@@ -70,7 +70,7 @@
     <dependency>
       <groupId>org.smartregister</groupId>
       <artifactId>plugins</artifactId>
-      <version>1.0.8</version>
+      <version>1.0.9</version>
     </dependency>
 
     <dependency>

plugins/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>org.smartregister</groupId>
     <artifactId>opensrp-gateway-plugin</artifactId>
-    <version>1.0.8</version>
+    <version>1.0.9</version>
   </parent>
 
   <artifactId>plugins</artifactId>

plugins/src/main/java/org/smartregister/fhir/gateway/plugins/BaseEndpoint.java

@@ -1,38 +1,11 @@
 package org.smartregister.fhir.gateway.plugins;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-import java.util.UUID;
-
 import javax.servlet.http.HttpServlet;
 
-import org.hl7.fhir.r4.model.Bundle;
-import org.hl7.fhir.r4.model.Resource;
+import ca.uhn.fhir.context.FhirContext;
+import ca.uhn.fhir.parser.IParser;
 
 public abstract class BaseEndpoint extends HttpServlet {
-    public Bundle createBundle(List<Resource> resourceList) {
-        Bundle responseBundle = new Bundle();
-        List<Bundle.BundleEntryComponent> bundleEntryComponentList = new ArrayList<>();
-
-        for (Resource resource : resourceList) {
-            bundleEntryComponentList.add(new Bundle.BundleEntryComponent().setResource(resource));
-        }
-
-        responseBundle.setEntry(bundleEntryComponentList);
-        responseBundle.setTotal(bundleEntryComponentList.size());
-        return responseBundle;
-    }
-
-    public Bundle createEmptyBundle(String requestURL) {
-        Bundle responseBundle = new Bundle();
-        responseBundle.setId(UUID.randomUUID().toString());
-        Bundle.BundleLinkComponent linkComponent = new Bundle.BundleLinkComponent();
-        linkComponent.setRelation(Bundle.LINK_SELF);
-        linkComponent.setUrl(requestURL);
-        responseBundle.setLink(Collections.singletonList(linkComponent));
-        responseBundle.setType(Bundle.BundleType.SEARCHSET);
-        responseBundle.setTotal(0);
-        return responseBundle;
-    }
+    protected final FhirContext fhirR4Context = FhirContext.forR4();
+    protected final IParser fhirR4JsonParser = fhirR4Context.newJsonParser().setPrettyPrint(true);
 }

plugins/src/main/java/org/smartregister/fhir/gateway/plugins/CacheHelper.java

@@ -6,6 +6,7 @@
 
 import org.apache.commons.lang3.StringUtils;
 import org.hl7.fhir.r4.model.DomainResource;
+import org.hl7.fhir.r4.model.Location;
 
 import com.github.benmanes.caffeine.cache.Cache;
 import com.github.benmanes.caffeine.cache.Caffeine;
@@ -16,6 +17,8 @@ public enum CacheHelper {
 
     Cache<String, DomainResource> resourceCache;
 
+    Cache<String, List<Location>> locationListCache;
+
     CacheHelper() {
         cache =
                 Caffeine.newBuilder()
@@ -27,6 +30,11 @@ public enum CacheHelper {
                         .expireAfterWrite(getCacheExpiryDurationInSeconds(), TimeUnit.SECONDS)
                         .maximumSize(DEFAULT_CACHE_SIZE)
                         .build();
+        locationListCache =
+                Caffeine.newBuilder()
+                        .expireAfterWrite(getCacheExpiryDurationInSeconds(), TimeUnit.SECONDS)
+                        .maximumSize(DEFAULT_CACHE_SIZE)
+                        .build();
     }
 
     private int getCacheExpiryDurationInSeconds() {

plugins/src/main/java/org/smartregister/fhir/gateway/plugins/Constants.java

@@ -33,6 +33,8 @@ public class Constants {
     public static final String DEFAULT_RELATED_ENTITY_TAG_URL =
             "https://smartregister.org/related-entity-location-tag-id";
     public static final String ROLE_ALL_LOCATIONS = "ALL_LOCATIONS";
+    public static final String MODE = "mode";
+    public static final String LIST = "list";
 
     public interface Literals {
         String EQUALS = "=";

plugins/src/main/java/org/smartregister/fhir/gateway/plugins/LocationHierarchyEndpoint.java

@@ -8,6 +8,7 @@
 import javax.servlet.http.HttpServletResponse;
 
 import org.apache.http.HttpStatus;
+import org.hl7.fhir.r4.model.Bundle;
 import org.smartregister.model.location.LocationHierarchy;
 
 import com.google.fhir.gateway.TokenVerifier;
@@ -38,21 +39,32 @@ protected void doGet(HttpServletRequest request, HttpServletResponse response)
         try {
             RestUtils.checkAuthentication(request, tokenVerifier);
             String identifier = request.getParameter(Constants.IDENTIFIER);
+            String mode = request.getParameter(Constants.MODE);
 
-            LocationHierarchy locationHierarchy =
-                    locationHierarchyEndpointHelper.getLocationHierarchy(identifier);
             String resultContent;
+            if (Constants.LIST.equals(mode)) {
+                Bundle resultBundle =
+                        locationHierarchyEndpointHelper.getPaginatedLocations(request);
+                resultContent = fhirR4JsonParser.encodeResourceToString(resultBundle);
 
-            if (org.smartregister.utils.Constants.LOCATION_RESOURCE_NOT_FOUND.equals(
-                    locationHierarchy.getId())) {
-                resultContent =
-                        fhirR4JsonParser.encodeResourceToString(
-                                createEmptyBundle(
-                                        request.getRequestURL() + "?" + request.getQueryString()));
             } else {
-                resultContent =
-                        fhirR4JsonParser.encodeResourceToString(
-                                createBundle(Collections.singletonList(locationHierarchy)));
+                LocationHierarchy locationHierarchy =
+                        locationHierarchyEndpointHelper.getLocationHierarchy(identifier);
+
+                if (org.smartregister.utils.Constants.LOCATION_RESOURCE_NOT_FOUND.equals(
+                        locationHierarchy.getId())) {
+                    resultContent =
+                            fhirR4JsonParser.encodeResourceToString(
+                                    Utils.createEmptyBundle(
+                                            request.getRequestURL()
+                                                    + "?"
+                                                    + request.getQueryString()));
+                } else {
+                    resultContent =
+                            fhirR4JsonParser.encodeResourceToString(
+                                    Utils.createBundle(
+                                            Collections.singletonList(locationHierarchy)));
+                }
             }
             response.setContentType("application/json");
             response.getOutputStream().print(resultContent);

plugins/src/main/java/org/smartregister/fhir/gateway/plugins/LocationHierarchyEndpointHelper.java

@@ -4,12 +4,16 @@
 import static org.smartregister.utils.Constants.LOCATION_RESOURCE_NOT_FOUND;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import javax.annotation.Nullable;
+import javax.servlet.http.HttpServletRequest;
 
 import org.hl7.fhir.r4.model.Bundle;
 import org.hl7.fhir.r4.model.Location;
+import org.hl7.fhir.r4.model.Resource;
 import org.hl7.fhir.r4.model.StringType;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -56,7 +60,7 @@ public LocationHierarchy getLocationHierarchyCore(String locationId) {
         LocationHierarchy locationHierarchy = new LocationHierarchy();
         if (location != null) {
             logger.info("Building Location Hierarchy of Location Id : " + locationId);
-            locationHierarchyTree.buildTreeFromList(getLocationHierarchy(locationId, location));
+            locationHierarchyTree.buildTreeFromList(getDescendants(locationId, location));
             StringType locationIdString = new StringType().setId(locationId).getIdElement();
             locationHierarchy.setLocationId(locationIdString);
             locationHierarchy.setId(LOCATION_RESOURCE + locationId);
@@ -69,11 +73,21 @@ public LocationHierarchy getLocationHierarchyCore(String locationId) {
         return locationHierarchy;
     }
 
-    private List<Location> getLocationHierarchy(String locationId, Location parentLocation) {
-        return descendants(locationId, parentLocation);
+    private List<Location> getLocationHierarchyLocations(
+            String locationId, Location parentLocation) {
+        List<Location> descendants;
+
+        if (CacheHelper.INSTANCE.skipCache()) {
+            descendants = getDescendants(locationId, parentLocation);
+        } else {
+            descendants =
+                    CacheHelper.INSTANCE.locationListCache.get(
+                            locationId, key -> getDescendants(locationId, parentLocation));
+        }
+        return descendants;
     }
 
-    public List<Location> descendants(String locationId, Location parentLocation) {
+    public List<Location> getDescendants(String locationId, Location parentLocation) {
 
         Bundle childLocationBundle =
                 getFhirClientForR4()
@@ -93,14 +107,14 @@ public List<Location> descendants(String locationId, Location parentLocation) {
                 Location childLocationEntity = (Location) childLocation.getResource();
                 allLocations.add(childLocationEntity);
                 allLocations.addAll(
-                        descendants(childLocationEntity.getIdElement().getIdPart(), null));
+                        getDescendants(childLocationEntity.getIdElement().getIdPart(), null));
             }
         }
 
         return allLocations;
     }
 
-    private @Nullable Location getLocationById(String locationId) {
+    public @Nullable Location getLocationById(String locationId) {
         Location location = null;
         try {
             location =
@@ -111,4 +125,43 @@ public List<Location> descendants(String locationId, Location parentLocation) {
         }
         return location;
     }
+
+    public Bundle getPaginatedLocations(HttpServletRequest request) {
+        String identifier = request.getParameter(Constants.IDENTIFIER);
+        String pageSize = request.getParameter(Constants.PAGINATION_PAGE_SIZE);
+        String pageNumber = request.getParameter(Constants.PAGINATION_PAGE_NUMBER);
+        Map<String, String[]> parameters = new HashMap<>(request.getParameterMap());
+
+        int count =
+                pageSize != null
+                        ? Integer.parseInt(pageSize)
+                        : Constants.PAGINATION_DEFAULT_PAGE_SIZE;
+        int page =
+                pageNumber != null
+                        ? Integer.parseInt(pageNumber)
+                        : Constants.PAGINATION_DEFAULT_PAGE_NUMBER;
+
+        int start = Math.max(0, (page - 1)) * count;
+        Location parentLocation = getLocationById(identifier);
+        List<Location> locations = getLocationHierarchyLocations(identifier, parentLocation);
+        List<Resource> resourceLocations = new ArrayList<>(locations);
+        int totalEntries = locations.size();
+
+        int end = Math.min(start + count, resourceLocations.size());
+        List<Resource> paginatedResourceLocations = resourceLocations.subList(start, end);
+        Bundle resultBundle;
+
+        if (locations.isEmpty()) {
+            resultBundle =
+                    Utils.createEmptyBundle(
+                            request.getRequestURL() + "?" + request.getQueryString());
+        } else {
+            resultBundle = Utils.createBundle(paginatedResourceLocations);
+            StringBuilder urlBuilder = new StringBuilder(request.getRequestURL());
+            Utils.addPaginationLinks(
+                    urlBuilder, resultBundle, page, totalEntries, count, parameters);
+        }
+
+        return resultBundle;
+    }
 }

plugins/src/main/java/org/smartregister/fhir/gateway/plugins/PractitionerDetailEndpoint.java

@@ -14,15 +14,11 @@
 
 import com.google.fhir.gateway.TokenVerifier;
 
-import ca.uhn.fhir.context.FhirContext;
-import ca.uhn.fhir.parser.IParser;
 import ca.uhn.fhir.rest.server.exceptions.AuthenticationException;
 
 @WebServlet("/PractitionerDetail")
 public class PractitionerDetailEndpoint extends BaseEndpoint {
     private final TokenVerifier tokenVerifier;
-    private final FhirContext fhirR4Context = FhirContext.forR4();
-    private final IParser fhirR4JsonParser = fhirR4Context.newJsonParser().setPrettyPrint(true);
     private final PractitionerDetailsEndpointHelper practitionerDetailsEndpointHelper;
 
     public PractitionerDetailEndpoint() throws IOException {
@@ -47,12 +43,12 @@ protected void doGet(HttpServletRequest request, HttpServletResponse response)
                     practitionerDetails.getId())) {
                 resultContent =
                         fhirR4JsonParser.encodeResourceToString(
-                                createEmptyBundle(
+                                Utils.createEmptyBundle(
                                         request.getRequestURL() + "?" + request.getQueryString()));
             } else {
                 resultContent =
                         fhirR4JsonParser.encodeResourceToString(
-                                createBundle(Collections.singletonList(practitionerDetails)));
+                                Utils.createBundle(Collections.singletonList(practitionerDetails)));
             }
 
             response.setContentType("application/json");