feat(rest): Api endpoint to retrieve package usage count

backend/common/src/main/java/org/eclipse/sw360/datahandler/db/ProjectRepository.java

@@ -220,7 +220,7 @@ public class ProjectRepository extends SummaryAwareRepository<Project> {
             "function(doc) {" +
                     "  if (doc.type == 'project' && doc.packageIds) {" +
                     "    for(var i in doc.packageIds) {" +
-                    "      emit(doc.packageIds[i], doc._id);" +
+                    "      emit(i, doc._id);" +
                     "    }" +
                     "  }" +
                     "}";

rest/resource-server/src/docs/asciidoc/packages.adoc

@@ -135,3 +135,44 @@ include::{snippets}/should_document_delete_package/curl-request.adoc[]
 
 ===== Example response
 include::{snippets}/should_document_delete_package/http-response.adoc[]
+
+
+[[resources-package-usage]]
+==== Get Package Usage Information
+
+A `GET` request to `/api/packages/{id}/usage` will get the usage information for a specific package, including whether the package is being used and the count of projects using it.
+
+===== Path parameters
+[cols="2,1,2"]
+|===
+|Name |Type |Description
+
+|id
+|String
+|The ID of the package to check usage for
+|===
+
+===== Response structure
+[cols="2,1,2"]
+|===
+|Path |Type |Description
+
+|count
+|Number
+|Number of projects using this package
+
+|isUsed
+|Boolean
+|Flag indicating if the package is used in any project
+|===
+
+===== Example request
+include::{snippets}/should_document_get_package_usage/curl-request.adoc[]
+
+===== Example response
+include::{snippets}/should_document_get_package_usage/http-response.adoc[]
+
+===== Error response
+When the package is not found:
+
+include::{snippets}/should_document_get_package_usage_not_found/http-response.adoc[]

rest/resource-server/src/main/java/org/eclipse/sw360/rest/resourceserver/packages/PackageController.java

@@ -52,6 +52,7 @@
 import org.eclipse.sw360.rest.resourceserver.core.HalResource;
 import org.eclipse.sw360.rest.resourceserver.core.OpenAPIPaginationHelper;
 import org.eclipse.sw360.rest.resourceserver.core.RestControllerHelper;
+import org.eclipse.sw360.rest.resourceserver.project.Sw360ProjectService;
 import org.eclipse.sw360.rest.resourceserver.release.Sw360ReleaseService;
 import org.eclipse.sw360.rest.resourceserver.user.Sw360UserService;
 import org.jetbrains.annotations.NotNull;
@@ -87,6 +88,9 @@ public class PackageController implements RepresentationModelProcessor<Repositor
     @NonNull
     private final SW360PackageService packageService;
 
+    @NonNull
+    private final Sw360ProjectService projectService;
+
     @NonNull
     private Sw360ReleaseService releaseService;
 
@@ -421,4 +425,41 @@ private ResponseEntity<CollectionModel<EntityModel<Package>>> getPackageResponse
         }
         return filterMap;
     }
+
+    @Operation(
+            summary = "Check if a package is being used and get the count.",
+            description = "Returns whether the package is being used and the total count of usages.",
+            tags = {"Packages"},
+            responses = {
+                    @ApiResponse(
+                            responseCode = "200", description = "Package usage information",
+                            content = {
+                                    @Content(mediaType = "application/json",
+                                            schema = @Schema(
+                                                    example = """
+                                                            {
+                                                              isUsed: true,
+                                                              count: 5
+                                                            }
+                                                            """
+                                            )
+                                    )
+                            }
+                    )
+            }
+    )
+
+    @RequestMapping(value = PACKAGES_URL + "/{id}/usage", method = RequestMethod.GET)
+    public ResponseEntity<Map<String, Object>> getPackageUsageInfo(
+            @Parameter(description = "The id of the package to check usage for")
+            @PathVariable("id") String id
+    ) throws TException {
+
+        Map<String, Object> response = new HashMap<>();
+        int usageCount = projectService.getProjectCountByPackageId(id);
+        response.put("isUsed", usageCount > 0);
+        response.put("count", usageCount);
+
+        return new ResponseEntity<>(response, HttpStatus.OK);
+    }
 }

rest/resource-server/src/main/java/org/eclipse/sw360/rest/resourceserver/project/Sw360ProjectService.java

@@ -1888,4 +1888,21 @@ private static PaginationData pageableToPaginationData(
         return new PaginationData().setDisplayStart((int) pageable.getOffset())
                 .setRowsPerPage(pageable.getPageSize()).setSortColumnNumber(column.getValue()).setAscending(ascending);
     }
+
+    public int getProjectCountByPackageId(String packageId) throws TException {
+        ThriftClients thriftClients = new ThriftClients();
+        ProjectService.Iface projectClient = thriftClients.makeProjectClient();
+        int count;
+        try {
+            count = projectClient.getProjectCountByPackageId(packageId);
+        } catch (SW360Exception sw360Exp) {
+            if (sw360Exp.getErrorCode() == 404) {
+                throw new ResourceNotFoundException("Requested Package Id Not Found");
+            }
+            else {
+                throw sw360Exp;
+            }
+        }
+        return count;
+    }
 }

rest/resource-server/src/test/java/org/eclipse/sw360/rest/resourceserver/restdocs/PackageSpecTest.java

@@ -51,6 +51,7 @@
 import org.eclipse.sw360.datahandler.thrift.users.UserGroup;
 import org.eclipse.sw360.rest.resourceserver.TestHelper;
 import org.eclipse.sw360.rest.resourceserver.packages.SW360PackageService;
+import org.eclipse.sw360.rest.resourceserver.project.Sw360ProjectService;
 import org.eclipse.sw360.rest.resourceserver.release.Sw360ReleaseService;
 import org.hamcrest.Matchers;
 import org.junit.Before;
@@ -60,6 +61,7 @@
 import org.springframework.hateoas.MediaTypes;
 import org.springframework.test.context.bean.override.mockito.MockitoBean;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.data.rest.webmvc.ResourceNotFoundException;
 
 @RunWith(SpringJUnit4ClassRunner.class)
 public class PackageSpecTest extends TestRestDocsSpecBase {
@@ -76,6 +78,9 @@ public class PackageSpecTest extends TestRestDocsSpecBase {
     @MockitoBean
     private Sw360ReleaseService releaseServiceMock;
 
+    @MockitoBean
+    private Sw360ProjectService projectServiceMock;
+
     private Package package1;
     private Package package2;
     private Package package3;
@@ -465,4 +470,36 @@ public void should_document_delete_package() throws Exception {
                 .accept(MediaTypes.HAL_JSON))
                 .andExpect(status().isOk());
     }
+
+    @Test
+    public void should_document_get_package_usage() throws Exception {
+        String packageId = package1.getId();
+        int projectCount = 5;
+
+        given(projectServiceMock.getProjectCountByPackageId(packageId)).willReturn(projectCount);
+
+        mockMvc.perform(get("/api/packages/" + packageId + "/usage")
+                        .header("Authorization", TestHelper.generateAuthHeader(testUserId, testUserPassword))
+                        .accept(MediaTypes.HAL_JSON))
+                .andExpect(status().isOk())
+                .andDo(this.documentationHandler.document(
+                        responseFields(
+                                fieldWithPath("count").description("Number of projects using this package"),
+                                fieldWithPath("isUsed").description("Flag indicating if the package is used in any project")
+                        )));
+    }
+
+    @Test
+    public void should_document_get_package_usage_not_found() throws Exception {
+        String packageId = "non-existent-id";
+
+        given(projectServiceMock.getProjectCountByPackageId(packageId))
+                .willThrow(new ResourceNotFoundException("Could not find package with id: " + packageId));
+
+        mockMvc.perform(get("/api/packages/" + packageId + "/usage")
+                        .header("Authorization", TestHelper.generateAuthHeader(testUserId, testUserPassword))
+                        .accept(MediaTypes.HAL_JSON))
+                .andExpect(status().isNotFound());
+    }
+
 }