Fix bug in SubmodelService: The Call of GetSubmodelMeta Changes The InMemory Storage Object

basyx.common/basyx.core/src/main/java/org/eclipse/digitaltwin/basyx/core/exceptions/FailedToDeepCopyException.java

@@ -0,0 +1,12 @@
+package org.eclipse.digitaltwin.basyx.core.exceptions;
+
+public class FailedToDeepCopyException extends RuntimeException {
+
+    public FailedToDeepCopyException(String objId, Throwable e) {
+        super(getMessage(objId), e);
+    }
+
+    private static String getMessage(String objId) {
+        return "Failed to deep copy object with id " + objId;
+    }
+}

basyx.submodelrepository/basyx.submodelrepository-backend/src/main/java/org/eclipse/digitaltwin/basyx/submodelrepository/backend/CrudSubmodelRepository.java

@@ -35,10 +35,6 @@
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
-import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.DeserializationException;
-import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.SerializationException;
-import org.eclipse.digitaltwin.aas4j.v3.dataformat.json.JsonDeserializer;
-import org.eclipse.digitaltwin.aas4j.v3.dataformat.json.JsonSerializer;
 import org.eclipse.digitaltwin.aas4j.v3.model.OperationVariable;
 import org.eclipse.digitaltwin.aas4j.v3.model.Reference;
 import org.eclipse.digitaltwin.aas4j.v3.model.Submodel;
@@ -54,6 +50,7 @@
 import org.eclipse.digitaltwin.basyx.core.pagination.PaginationInfo;
 import org.eclipse.digitaltwin.basyx.core.pagination.PaginationSupport;
 import org.eclipse.digitaltwin.basyx.http.Base64UrlEncoder;
+import org.eclipse.digitaltwin.basyx.serialization.SubmodelMetadataUtil;
 import org.eclipse.digitaltwin.basyx.submodelrepository.SubmodelRepository;
 import org.eclipse.digitaltwin.basyx.submodelservice.SubmodelService;
 import org.eclipse.digitaltwin.basyx.submodelservice.SubmodelServiceFactory;
@@ -255,7 +252,7 @@ public Submodel getSubmodelByIdMetadata(String submodelId) throws ElementDoesNot
 
 		Submodel submodel = getSubmodel(submodelId);
 
-		return getSubmodelDeepCopy(submodel);
+		return SubmodelMetadataUtil.extractMetadata(submodel);
 	}
 
 	@Override
@@ -303,23 +300,6 @@ private void throwIfMissingId(Collection<Submodel> submodels) {
 		submodels.stream().map(Submodel::getId).forEach(this::throwIfSubmodelIdEmptyOrNull);
 	}
 
-	private Submodel getSubmodelDeepCopy(Submodel submodel) {
-
-		try {
-			String submodelAsJSON = new JsonSerializer().write(submodel);
-
-			Submodel submodelDeepCopy = new JsonDeserializer().read(submodelAsJSON, Submodel.class);
-
-			submodelDeepCopy.setSubmodelElements(null);
-
-			return submodelDeepCopy;
-		} catch (DeserializationException e) {
-			throw new RuntimeException("Unable to deserialize the Submodel", e);
-		} catch (SerializationException e) {
-			throw new RuntimeException("Unable to serialize the Submodel", e);
-		}
-	}
-
 	private SubmodelService getSubmodelServiceOrThrow(String submodelId) {
 		Submodel submodel = submodelBackend.findById(submodelId).orElseThrow(() -> new ElementDoesNotExistException(submodelId));
 

basyx.submodelservice/basyx.submodelservice-core/src/main/java/org/eclipse/digitaltwin/basyx/serialization/SubmodelMetadataUtil.java

@@ -0,0 +1,73 @@
+/*******************************************************************************
+ * Copyright (C) 2024 the Eclipse BaSyx Authors
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * 
+ * SPDX-License-Identifier: MIT
+ ******************************************************************************/
+
+package org.eclipse.digitaltwin.basyx.serialization;
+
+import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.DeserializationException;
+import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.SerializationException;
+import org.eclipse.digitaltwin.aas4j.v3.dataformat.json.JsonDeserializer;
+import org.eclipse.digitaltwin.aas4j.v3.dataformat.json.JsonSerializer;
+import org.eclipse.digitaltwin.aas4j.v3.model.Submodel;
+import org.eclipse.digitaltwin.basyx.core.exceptions.FailedToDeepCopyException;
+
+public final class SubmodelMetadataUtil {
+
+    private SubmodelMetadataUtil() {
+    }
+
+    /**
+     * Returns a new submodel that only contains the metadata of the given submodel.
+     *
+     * @param submodel
+     * @return A new submodel with the metadata of the given submodel.
+     */
+    public static Submodel extractMetadata(Submodel submodel) {
+        Submodel submodelDeepCopy = deepCopy(submodel);
+
+        submodelDeepCopy.setSubmodelElements(null);
+
+        return submodelDeepCopy;
+    }
+
+    /**
+     * Deep copy a submodel.
+     * 
+     * @param submodel
+     * @return A deep copy of the submodel.
+     * 
+     * @throws FailedToDeepCopyException
+     * 
+     */
+    public static Submodel deepCopy(Submodel submodel) {
+        try {
+            String submodelAsJSON = new JsonSerializer().write(submodel);
+
+            return new JsonDeserializer().read(submodelAsJSON, Submodel.class);
+
+        } catch (DeserializationException | SerializationException e) {
+            throw new FailedToDeepCopyException(submodel.getId(), e);
+        }
+    }
+}

basyx.submodelservice/basyx.submodelservice-http/src/main/java/org/eclipse/digitaltwin/basyx/submodelservice/http/SubmodelServiceHTTPApiController.java

@@ -46,6 +46,7 @@
 import org.eclipse.digitaltwin.basyx.http.pagination.PagedResult;
 import org.eclipse.digitaltwin.basyx.http.pagination.PagedResultPagingMetadata;
 import org.eclipse.digitaltwin.basyx.pagination.GetSubmodelElementsResult;
+import org.eclipse.digitaltwin.basyx.serialization.SubmodelMetadataUtil;
 import org.eclipse.digitaltwin.basyx.submodelservice.SubmodelService;
 import org.eclipse.digitaltwin.basyx.submodelservice.value.SubmodelElementValue;
 import org.eclipse.digitaltwin.basyx.submodelservice.value.SubmodelValueOnly;
@@ -164,9 +165,8 @@ public ResponseEntity<Submodel> getSubmodelMetadata(@Parameter(in = ParameterIn.
 			"core" }, defaultValue = "deep")) @Valid @RequestParam(value = "level", required = false, defaultValue = "deep") String level) {
 
 		Submodel submodel = service.getSubmodel();
-		submodel.setSubmodelElements(null);
 
-		return new ResponseEntity<Submodel>(submodel, HttpStatus.OK);
+		return new ResponseEntity<>(SubmodelMetadataUtil.extractMetadata(submodel), HttpStatus.OK);
 	}
 
 	@Override
@@ -320,5 +320,4 @@ private void closeInputStream(InputStream fileInputstream) {
 			e.printStackTrace();
 		}
 	}
-
 }

basyx.submodelservice/basyx.submodelservice-http/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/http/SubmodelServiceSubmodelTestSuiteHTTP.java

@@ -25,13 +25,16 @@
 
 package org.eclipse.digitaltwin.basyx.submodelservice.http;
 
+import static org.junit.Assert.assertEquals;
+
 import java.io.FileNotFoundException;
 import java.io.IOException;
 
 import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
 import org.apache.hc.core5.http.ParseException;
 import org.eclipse.digitaltwin.basyx.http.serialization.BaSyxHttpTestUtils;
 import org.junit.Test;
+import org.springframework.http.HttpStatus;
 
 /**
  * Base testsuite for all Submodel Service HTTP tests related to the Submodel
@@ -63,6 +66,19 @@ public void getSubmodelMetadata() throws IOException, ParseException {
 		BaSyxHttpTestUtils.assertSameJSONContent(expected, submodelMetadata);
 	}
 
+	@Test
+	public void getSubmodelMetadata_preservesSubmodel() throws IOException, ParseException {
+
+		String submodelBefore = BaSyxHttpTestUtils.getResponseAsString(BaSyxHttpTestUtils.executeGetOnURL(getURL()));
+
+		CloseableHttpResponse response = BaSyxHttpTestUtils.executeGetOnURL(getSubmodelMetadataURL());
+		assertEquals(HttpStatus.OK.value(), response.getCode());
+
+		String submodelAfter = BaSyxHttpTestUtils.getResponseAsString(BaSyxHttpTestUtils.executeGetOnURL(getURL()));
+
+		BaSyxHttpTestUtils.assertSameJSONContent(submodelBefore, submodelAfter);
+	}
+
 	private String getSubmodelMetadataURL() {
 		return getURL() + "/$metadata";
 	}